Research ArticleAntidepressant Effects of Mallotus oppositifoliusin Acute Murine Models

Kennedy K E Kukuia1 Priscilla K Mante2 Eric Woode2

Elvis O Ameyaw3 and Donatus W Adongo2

1 Department of Pharmacology University of Ghana Medical School College of Health Sciences University of Ghana Accra Ghana2Department of Pharmacology Faculty of Pharmacy and Pharmaceutical Sciences Kwame Nkrumah Universityof Science and Technology Kumasi Ghana

3Department of Biomedical and Forensic Sciences School of Biological Science University of Cape Coast Cape Coast Ghana

Correspondence should be addressed to Eric Woode ewoodepharmknustedugh

Received 25 November 2013 Accepted 18 December 2013 Published 12 March 2014

Academic Editors P S DrsquoAquila A Fernandez-Guasti and S Mingmalairak

Copyright copy 2014 Kennedy K E Kukuia et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

Objective Hydroalcoholic extract of leaves of Mallotus oppositifolius (MOE) a plant used for CNS conditions in Ghana wasinvestigated for acute antidepressant effects in the forced swimming (FST) and tail suspension tests (TST) Results In bothFST and TST MOE (10 30 and 100mg kgminus1) significantly decreased immobility periods and frequencies A 3-day pretreatmentwith 200mg kgminus1 ip para-chlorophenylalanine (PCPA) a tryptophan hydroxylase inhibitor reversed the decline in immobilityand the increase of swimming score induced by MOE in the modified FST Pretreatment with reserpine alone (1mg kgminus1) 120572-methyldopa alone (400mg kgminus1 ip) or a combination of both drugs failed to reverse the decline in immobility or the increasein swimming score caused by the extract in the modified FST The extract potentiated the frequency of head twitch responsesinduced by 5-hydroxytryptamine Pretreatmentwith d-serine (600mg kgminus1 ip) glycineNMDAagonist abolished the behaviouraleffects of MOE while d-cycloserine (25mg kgminus1 ip) a glycineNMDA partial agonist potentiated it in both TST and modifiedFST Conclusion The extract exhibited antidepressant effects in mice which is mediated by enhancement of serotoninergicneurotransmission and inhibition of glycineNMDA receptor activation

1 Introduction

Depression is an extremely common pathological complexwith psychological neuroendocrine and pathological symp-toms [1] It is a leading cause of disability worldwide andhas a very significant impact on morbidity mortality andhealth care cost [2ndash4] Disconcertion in monoaminergicneurotransmission especially serotonin and noradrenalineneurotransmission is considered the major cause of theobserved symptoms of depression Unfortunately the efficacyof these medications is unsatisfactory and multiple sideeffects are common [5] It is estimated that about 40of patients have conditions refractory to current medica-tions Furthermore these drugs require at least 2ndash4 weeksof administration before producing clinically meaningfulimprovement in the symptoms [6] These reasons underpin

the need for novel therapeutic agents with less side effectsand faster onset of action [7 8] Also both preclinical andclinical studies support the role of NMDA receptor antago-nists as possible therapeutic agents for depression [5 9 10]For instance ketamine and memantine have demonstratedrapid and profound antidepressant effects clinically [11 12]Numerous behavioural studies have further demonstratedthat antagonists and partial agonists at the glycine coagonistsite of the NMDA receptor have antidepressant potentialswith less severe side effects [13] While the search of newerantidepressants continues renewed interest in medicinalplants for exampleMallotus oppositifolius for the treatmentof many CNS disorders has been on the ascendancy [14ndash16]

Despite the use of Mallotus oppositifolius in treatingpsychiatric and affective disorders in Ghana there is noscientific data on its antidepressant effect Thus the present

Hindawi Publishing CorporationISRN PharmacologyVolume 2014 Article ID 324063 12 pageshttpdxdoiorg1011552014324063

2 ISRN Pharmacology

study investigated the effect of the hydroalcoholic leaf extractof the plant in acute antidepressant modelsmdashthe forcedswim (FST) and tail suspension tests (TST) The effectsof the extract on the monoaminergic system (serotoninand noradrenaline) as well as the glycineNMDA receptorcomplex were investigated in order to elucidate the possiblemechanism(s) of action of the extract

2 Materials

Leaves of the plantMallotus oppositifoliuswere collected fromthe wild around the Kwame Nkrumah University of Scienceand Technology (KNUST) Kumasi Ghana (6∘4110158406410158401015840N1∘33101584042810158401015840W) and authenticated at the Department of HerbalMedicine of the Faculty of Pharmacy and Pharmaceuti-cal Sciences KNUST Kumasi where a voucher specimen(KNUSTFP03509) has been deposited After air-drying for7 days the leaves were pulverized with a hammer-mill andthe powder extracted by cold maceration using 70 (vv)ethanol in water over a period of 72 h The resulting extractwas concentrated under moderate temperature (60∘C) andpressure to a syrupy mass on a rotary evaporator The syrupymass was then dried to a dark brown semisolid mass usingwater bath and kept in a desiccator till it was ready to be usedThe final yield was 95 (ww) This is subsequently referredto asMallotus oppositifolius extract (MOE) or extract

21 Animals Male ICRmice were obtained from and housedat the animal facility of the Department of PharmacologyKNUST Kumasi GhanaThe animals were housed in groupsof five in stainless steel cages (34times47times18 cm) with soft woodshavings as bedding fed with normal commercial pellet diet(GAFCO Tema) given water ad libitum and maintainedunder laboratory conditions All animals used in these studieswere treated in accordance with the Guide for the Careand Use of Laboratory Animals [17] and experiments wereapproved by the College Ethics Committee

22 Chemicals Fluoxetine hydrochloride (Prozac) wasfrom Eli Lilly and Co Basingstoke England Imipraminehydrochloride (Tofranil) from Mallinckrodt Pharmaceuti-cals Ireland Desipramine hydrochloride d-serine d-cycloserine 120572-methyldopa reserpine and para-chloro-phenylalanine were purchased from Sigma-Aldrich Inc StLouis MO USA

23 Forced Swimming Test (FST) The FST was based on thatdescribed by Porsolt et al [18] Mice were divided into tengroups of five animals each and received the vehicle (water)extract (10 30 or 100mg kgminus1 po) or the standard referencedrugs fluoxetine (3 10 or 30mg kgminus1 po) imipramine (310 or 30mg kgminus1 po) One hour after oral administration ofthe test compoundsmicewere gently placed individually intotransparent cylindrical polyethylene tanks (25 cmhigh 10 cminternal diameter) containing water (25 to 28∘C) up to a levelof 20 cm and left there for 5min Each session was recordedby a video camera suspended approximately 100 cm abovethe cylinders An observer scored the duration of immobility

(when mouse floated upright in the water and made onlysmall movements to keep its head above water) during thelast 5min test from the videotapes with the aid of the publicdomain software JWatcher Version 10 (University of Cali-fornia Los Angeles USA andMacquarie University SydneyAustralia available at httpwwwjwatcheruclaedu)

24 Tail Suspension Test The TST was carried out as pre-viously described by Steru et al [19] Mice were allowed toacclimatize to the room for 35ndash4 h before the test Groupsof ten mice were treated with MOE (10 30 or 100mg kgminus1po) fluoxetine (3 10 or 30mg kgminus1 po) and imipramine(3 10 or 30mg kgminus1 po) or vehicle One hour after oraladministration of the test compoundsmicewere individuallysuspended by the tail from a horizontal bar (distance fromfloor = 30 cm) using adhesive tape (distance from tip of tail= 1 cm) Duration of immobility defined as the absence ofall movement except for those required for respiration wasrecorded by an observer for 5min from video recordingsof the test as described above for forced swimming testMice that climbed up on their tails during the test sessionwere gently pulled down and testing continued Mice thatcontinued to climb their tails were excluded from the study

25 Involvement of Noradrenergic Systems Mice were pre-treatedwith reserpine andor120572-methyldopa (120572-MD) in orderto investigate the possible role of noradrenergic system inthe actions of MOE [20] The doses of 120572-MD and reserpinewere chosen on the basis of work done by others [20 21] Todeplete newly synthesized pools of noradrenaline (NE) anddopamine (DA) mice were treated with a single dose of 120572-MD (400mg kgminus1 ip) 35 hours before behavioural testingTo deplete vesicular pools of NE and DA mice were treatedwith a single dose of reserpine (1mg kgminus1 sc) 24 h beforebehavioral testing In an effort to deplete both the vesicularand cytoplasmic pools of NE and DA mice were pretreatedwith a combination of reserpine (1mg kgminus1 sc 24 h beforebehavioral testing) and 120572-MD (200mg kgminus1 ip 35 hoursbefore behavioral testing) respectively

26 Involvement of Serotoninergic Systems Mice weregrouped into groups of five (5) forming ten (20) groupspCPA (200mg kgminus1 ip) was administered once daily for3 consecutive days to some of the animals On the fourthday group 1 received saline without pretreatment group 2received pCPA after pretreatment groups 3 to 5 receivedMOE (10 30 and 100mg kgminus1) without pretreatment groups6 to 8 received MOE (10 30 and 100mg kgminus1 po) afterpretreatment groups 9 to 11 received fluoxetine (3 10 and30mg kgminus1 po) alone groups 12 to 14 received fluoxetine(3 10 and 30mg kgminus1 po) after pretreatment groups 15ndash17received imipramine (3 10 and 30mg kgminus1 po) aloneand finally groups 18ndash20 received imipramine (3 10 and30mg kgminus1 po) after pretreatment After the tail suspensionsessions mice were taken through the modified forcedswimming test The modified forced swimming test followedthe same procedure described above except that the depth of

ISRN Pharmacology 3

water was changed to 20 cm For tail suspension immobilityperiod was scored whilst for the modified swimming testmean immobility counts mean swimming counts and meanclimbing counts were scored

27 Involvement of GlycineNMDA Neurotransmission Micewere divided into 2 groups A and B Groups A and B werefurther subdivided into 6 groups each (119899 = 8) Brieflyfive groups of mice from group A received d-cycloserine(25mg kgminus1 ip) and 30min after the first three groupsreceived an oral dose of the extract (10ndash100mg kgminus1) withthe last two groups receiving either fluoxetine (10mg kgminus1)or desipramine (10mg kgminus1 ip) The sixth group receivedonly d-cycloserine Again five groups of mice from groupB received d-serine (600mg kgminus1) and 30min after thefirst three groups received an oral dose of the extract (10ndash100mg kgminus1) with the last two groups receiving either flu-oxetine (10mg kgminus1 po) or desipramine (10mg kgminus1 ip)The sixth group from group B received only d-serine Theforced swim and tail suspension tests were used as describedabove to investigate the antidepressant mechanism Pedallingbehaviour was defined as the continuous movement of thepaw of the mice without moving the body while curling wasdefined as the raising of the head of the mouse towards itshind paws

28 Statistics GraphPad Prism for Windows version 403(GraphPad Software San Diego CA USA) was used forall data and statistical analyses 119875 lt 005 was consideredstatistically significant In all the tests a sample size of tenanimals (119899 = 10) were used The time-course curves weresubjected to two-way (treatment times time) repeated measuresanalysis of variance (ANOVA) with Bonferronirsquos post hoc testTotal immobility time distance travelled and time takento find the hidden platform and change in weight for eachtreatment were calculated in arbitrary unit as the area underthe curve (AUC) Differences in AUCs were analysed byANOVA followed by Newman Keulsrsquo post hoc test

3 Results

31 Forced Swimming and Tail Suspension Tests MOE (10ndash100mg kgminus1 po) administered 60min before the test periodsignificantly decreased the frequency of immobility (119865

319

=

2147 119875 lt 0001) (Figure 1(a)) and immobility periods ofmice (119865

319

= 1434 119875 lt 0001) (Figure 1(d)) in a dosedependent manner in the FST In the TST both frequency(119865654

= 0486 119875 = 08159) (Figures 2(a) 2(b) and 2(c))and duration (119865

652

= 2557 119875 lt 0001) (Figures 2(d)2(e) and 2(f)) of immobility decreased indicating significantantidepressant activity

32 Involvement of Noradrenergic Mechanisms Pretreat-ment with reserpine (1mg kgminus1 sc) alone 120572-methyldopa(400mg kgminus1 po) alone or a concomitant administration ofreserpine (1mg kgminus1 sc) and 120572-methyldopa (200mg kgminus1po) did not reverse the decline in immobility caused by

the extract MOE (10ndash100mg kgminus1 po) in the forced swimtest (FST) (Figures 3(a) 3(d) and 3(g)) Results obtainedfor fluoxetine-treated groups (FLX) (3ndash30mg kgminus1 po) weresimilar to that of the extract-treated groups (Figures 3(b)3(e) and 3(h)) In contrast the antidepressant effect ofimipramine (IMI) was reversed by either reserpine alone120572-methyldopa alone or a concomitant administration ofreserpine and 120572-methyldopa (Figures 3(c) 3(f) and 3(i))

33 Involvement of Serotoninergic Mechanism Pretreatmentof mice with pCPA (200mg kgminus1) abolished the antidepres-sant effect ofMOE (10ndash100mg kgminus1 po) and fluoxetine FLX(3ndash30mg kgminus1 po) but not imipramine IMI (3ndash30mg kgminus1po) in the FST The mean counts for immobility (119865

732

=

1463 119875 lt 00001) (Figure 4(a)) swimming (119865732

= 4474119875 lt 00001) (Figure 4(d)) and climbing (119865

732

= 1121 119875 =03742) (Figure 4(g)) in the extract-treated group after pCPApretreatment did not show any difference when comparedwith the control Similar results as above were observed forFLX-treated groups but not imipramine (Figures 4(b)-4(c)4(e)-4(f) and 4(h)-4(i))

In an attempt to investigate the possible involvementof 5-HT

2A receptor activation in the antidepressant actionof the extract mice were given 5-hydroxytryptophan afterextract pretreatment to induced head twitch responses Itwas observed from the time course curve that the extractas well as fluoxetine increased the head twitch responsessignificantly for the period of 30 minutes (Figures 5(a) and5(c)) Response peaked after 15 minutes One-way ANOVAfollowed by Newman Keulsrsquo test of the areas under the curve(AUCs) showed a dose dependent increase in the head twitchresponse for both extract and fluoxetine (Figures 5(b) and5(d))

34 Involvement of GlycineNMDA Receptor Complex In theTST MOE (100mg kgminus1 po) fluoxetine FLX (10mg kgminus1po) and desipramine DSP (10mg kgminus1 ip) exhibited sig-nificant antidepressant effect by decreasing mean immobilityscore which was reversed by d-serine DS (600mg kgminus1 ip)pretreatment (Figure 6(a)) Pretreatment with d-cycloserineDCS (25mg kgminus1 ip) potentiated the effect of MOE andFLX (but not DSP) by further decreasing mean immobilityscore (Figure 6(b)) MOE alone did not affect curling scoreand this was not changed by DS pretreatment (Figure 6(e))FLX and DSP alone caused slight increase in the curlingscore which was reversed by DS Pretreatment with DCSsignificantly increased curling score of MOE but caused onlya modest increase in both FLX and DSP treated groups(Figure 6(f)) MOE DS DCS FLX and DSP alone increasedswinging score DS pretreatment partially inhibited swingingbehaviour byMOE but totally in FLX andDSP treated groups(Figure 6(c)) DCS pretreatment also inhibited swingingbehaviour by MOE and DSP but not FLX (Figure 6(d))

In the forced swim test MOE FLX and DSP decreasedimmobility score and this was reversed by DS pretreatment(Figure 7(a)) Pretreatment with DCS potentiated the effectof MOE and FLX (but not DSP) by further decreasing

4 ISRN Pharmacology

Freq

uenc

y14

12

10

8

6

4

2

0

Ctrl 10 30 100

lowastlowastlowastlowast lowastlowastlowast

lowastlowastlowast

MOE (mg kgminus1)

(a)

3 10 30

lowastlowastlowast

lowastlowastlowastlowastlowastlowast lowastlowastlowastlowastlowastlowast

lowastlowastlowast

FLX (mg kgminus1)

(b)

3 10 30

lowastlowast

lowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

daggerdaggerdagger

daggerdaggerdagger

daggerdaggerdagger

IMI (mg kgminus1)

(c)

MobilityImmobility

Dur

atio

n (s

)

350

300

250

200

150

100

50

0

daggerdaggerdaggerdaggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

Ctrl 10 30 100

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

MOE (mg kgminus1)

(d)

daggerdaggerdagger daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowastlowastlowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

lowastlowastlowast

3 10 30

MobilityImmobility

FLX (mg kgminus1)

(e)

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

3 10 30

MobilityImmobility

IMI (mg kgminus1)

(f)

Figure 1 Effects of extract MOE (10ndash100mg kgminus1) fluoxetine FLX (3ndash30mg kgminus1) and imipramine IMI (3ndash30mg kgminus1) treatment on (ab and c) the frequency of mobility and immobility and (d e and f) duration of mobility and immobility in the FST Data are presented asgroup means plusmn SEM significantly different from control lowastlowastlowast119875 lt 0001 lowastlowast119875 lt 001 (one-way ANOVA followed by Newman Keulsrsquo test)daggerdaggerdagger

119875 lt 0001 comparison between effect and dose (two-way ANOVA followed by Bonferronirsquos test)

immobility score (Figure 7(b)) MOE and FLX unlike DSPincreased swimming behaviour which was inhibited by DSbut increased by DCS pretreatment (Figures 7(c) and 7(d))Climbing scores were decreased by both MOE and FLX andthis was not affected by both DS and DCS pretreatment(Figures 7(e) and 7(f)) DSP on the contrary increasedclimbing score which was unaffected by DCS pretreatmentbut decreased by DS

4 Discussion

Results of the study demonstrated that MOE has significantantidepressant effect in both the forced swimming and thetail suspension tests In both animal models percentageimmobility and frequency of immobility were decreased byextract treatment Reduction in immobility has been used asthe primary index for antidepressant effect of test substancesin these modelsmdashalmost all antidepressants in clinical use

induce a decrease in immobility in rodents whilst other drugsfail to give the same response [22 23]

Preclinical and clinical studies suggest that depletionof a monoamine implicated in depression pathophysiologymay abolish the antidepressant effect of a substance if thesubstance depends on that particular monoamine for itsantidepressant effect [20 24]Hencewhen 5-HTwas depletedby pretreating mice for 3 days with the tryptophan hydrox-ylase inhibitor para-chlorophenylalanine (pCPA) the effectsof drugs that act by enhancing 5-HT neurotransmission wereabolished [25 26] while those that act on noradrenergicpathways were not affected [26ndash28] The inhibition of theantidepressant effect of MOE by pCPA in both TST andFST suggests that its antidepressant effect is dependenton enhancement of serotoninergic neurotransmission Thelack of antidepressant effect of fluoxetine in pCPA-treatedmice is consistent with the hypothesis that fluoxetine elicitsits acute behavioural effects by increasing extracellular 5-HT after blockade of the serotonin transporter [29] The

ISRN Pharmacology 5

Freq

uenc

y10

8

6

4

2

0

Ctrl 10 30 100

lowast

MOE (mg kgminus1)

(a)

10 303

lowast

lowast

FLX (mg kgminus1)

(b)

10 303

lowast

lowastlowast

IMI (mg kgminus1)

(c)

Dur

atio

n (s

)

350

300

250

200

150

100

50

0

MobilityImmobility

Ctrl 10 30 100

daggerdagger daggerdagger

daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast lowastlowastlowast lowastlowastlowast

lowastlowastlowast lowastlowastlowast

lowastlowastlowast

MOE (mg kgminus1)

(d)

MobilityImmobility

10 303

daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

FLX (mg kgminus1)

(e)

MobilityImmobility

10 303

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

IMI (mg kgminus1)

(f)

Figure 2 Effect of the extract MOE (10 30 and 100mg kgminus1) fluoxetine FLX (3 10 and 30mg kgminus1) and imipramine IMI (3 10 and30mg kgminus1) treatment on the (a b and c) frequency of mobility and immobility and (d e and f) duration of mobility and immobility in theTST Data are presented as group means plusmn SEM lowastlowastlowast119875 lt 0001 lowastlowast119875 lt 001 compared to vehicle-treated group (one-way ANOVA followedby Newman Keulsrsquo test) daggerdaggerdagger119875 lt 0001 comparison effect and dose (two-way ANOVA followed by Bonferronirsquos test)

extract and fluoxetine increased swimming score which wasreversed with pCPA pretreatment further supporting theiraction on the serotoninergic system [27 30] Both MOE andfluoxetine did not affect mean climbing score suggesting thattheir behavioural effect may not depend on noradrenergicpathways

Further evidence suggesting that the extract enhances 5-HTneurotransmissionwas derived from its ability to increasehead twitch responses induced by 5-HTP The head twitchresponse (HTR) in rodents induced by 5-hydroxytryptophan(5-HTP) a precursor of 5-HT [31] is considered as a specificbehavioural model for the activation of serotoninergic neu-ron specifically 5-HT

2A receptors [32]Thus it can be inferredthat MOE may be acting via direct or indirect activation of5-HT2A receptors Fluoxetine also increased the frequency of

HTRsThis result is consistentwith a number of studieswherefluoxetine elicited similar responses [33 34]

The present experiments also examined the role of nora-drenaline and dopamine in the acute behavioural effects of

the extract in the modified FST by using drugs that interferewith their neurotransmitter synthesis or release Depletionwith 120572-methyldopa an L-aromatic amino acid decarboxylaseinhibitor that inhibits the biosynthesis of catecholamines and5-HT [35] failed to attenuate the behavioural effects of MOEand fluoxetine while that of imipramine was abolished Thissuggests that MOE may not be affected by the biosynthesisof noradrenaline or dopamine Moreover when vesicularpools were depleted by reserpine the decrease in immobilityelicited by MOE or fluoxetine was not affected Here againthe effect of imipramine was attenuated Reserpine is anirreversible inhibitor of the vesicular monoamine transporter2 (VMAT-2) which is located primarily within the CNS andis responsible for transporting monoamines from the cyto-plasm into secretory vesicles [36 37] Treatment with reser-pine therefore leads to depletion of vesicular monoaminestoresmdashboth serotonin and noradrenaline [38] suggestingboth serotonin and noradrenaline might be important inthe antidepressant effects of imipramine The inability of

6 ISRN Pharmacology

Ctrl 10 30 100

lowastlowastlowastlowast

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lowastlowastlowast

lowastlowastlowastlowastlowastlowastIm

mob

ility

tim

e (s)

100

80

60

40

20

0

Untreated120572-MD-treated

MOE (mg kgminus1)

(a)

lowast

lowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowastlowastlowastlowast

Untreated

3 10 30

120572-MD-treated

FLX (mg kgminus1)

(b)

lowast

daggerdagger

daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

Untreated

3 10 30

120572-MD-treated

IMI (mg kgminus1)

(c)

lowastlowast

lowastlowast lowastlowastlowastlowastlowast

lowastlowastlowastlowastlowastlowast

UntreatedReserpinised

Ctrl 10 30 100

Imm

obili

ty ti

me (

s)

100

80

60

40

20

0

MOE (mg kgminus1)

(d)

lowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowast

3 10 30

UntreatedReserpinised

FLX (mg kgminus1)

(e)

lowast

daggerdaggerdagger

daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

3 10 30

UntreatedReserpinised

IMI (mg kgminus1)

(f)

daggerdagger

lowastlowastlowastlowastlowast

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Untreated

120

Imm

obili

ty ti

me (

s)

100

80

60

40

20

0

Ctrl 10 30 100

120572-MDres-treated

MOE (mg kgminus1)

(g)

lowast

lowastlowastlowast

lowastlowastlowast lowastlowastlowast

lowastlowastlowastlowastlowastlowast

3 10 30

Untreated120572-MDres-treated

FLX (mg kgminus1)

(h)

lowastlowast

daggerdaggerdaggerdaggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

3 10 30

Untreated120572-MDres-treated

IMI (mg kgminus1)

(i)

Figure 3 Effects of (andashc) reserpine alone (dndashf) 120572-methyldopa 120572-MD alone or (gndashi) both reserpine and 120572-methyldopa on duration ofimmobility of MOE (10ndash100mg kgminus1 po) fluoxetine (3ndash30mg kgminus1 po) and imipramine (3ndash30mg kgminus1 po) treatment in the FST Dataare presented as mean plusmn SEM of 5 animals significantly different from control lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 by one-way ANOVA followed byNewman Keulsrsquo test dagger119875 lt 005 daggerdagger119875 lt 001 and daggerdaggerdagger119875 lt 0001 significant difference between treatment and dose (two-way ANOVA withBonferroni post hoc test)

ISRN Pharmacology 7

Ctrl 10 30 100

Imm

obili

ty ti

me (

s)

60

40

50

20

10

30

0

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

MOE (mg kgminus1)

(a)

3 10 30

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

FLX (mg kgminus1)

(b)

3 10 30

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

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IMI (mg kgminus1)

(c)

Swim

min

g tim

e (s)

40

50

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10

30

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(d)

3 10 30

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FLX (mg kgminus1)

(e)

3 10 30

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IMI (mg kgminus1)

(f)

Clim

bing

tim

e (s)

40

50

20

10

30

0

Ctrl 10 30 100

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MOE (mg kgminus1)

(g)

3 10 30

dagger

dagger

lowastlowastlowast

UntreatedPCPA-treated

FLX (mg kgminus1)

(h)

3 10 30

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

UntreatedPCPA-treated

IMI (mg kgminus1)

(i)

Figure 4 Effects of pCPA (200mg kgminus1) pretreatment on the (andashc) mean immobility counts (dndashf) swimming counts and (gndashi) climbingcounts of oral doses of extract MOE (10ndash100mg kgminus1) fluoxetine FLX (3ndash30mg kgminus1) and IMI (3ndash30mg kgminus1) treated groups in the FSTData are presented as mean plusmn SEM significantly different from control lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 by Newman Keulsrsquo test daggerdaggerdagger119875 lt 0001(two-way ANOVA followed by Bonferronirsquos post test comparison between drug treatment and dose)

8 ISRN Pharmacology

0

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Num

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f hea

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itche

s

AUC

MOEMOEMOE10mg kgminus1

30mg kgminus1100mg kgminus1

(a)

0 5 10 15 20 25 30

Time (min)Ctrl

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

0

5

10

15

20

25

30

35

Num

ber o

f hea

d tw

itche

sFLX

FLXFLX

Ctrl 3 10 30

160

120

80

40

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AUC

3mg kgminus110mg kgminus130mg kgminus1

(b)

Figure 5 Effect of MOE (10ndash100mg kgminus1 po) and fluoxetine (3ndash30mg kgminus1 po) on the time course curve of head twitch response test andtheir corresponding AUCs (a and b) in the same test represented as bar graphs Data was presented as mean plusmn SEM (119899 = 6) lowastlowastlowast119875 lt 0001lowastlowast

119875 lt 001 compared to vehicle-treated group (one-way ANOVA followed by Newman Keulsrsquo test)

reserpine pretreatment to reverse the antidepressant effectsof the extract and fluoxetine however seems to suggest thatreserpine does not affect vesicular storage of 5-HT to thesame extent as that of noradrenaline In fact this assertionis consistent with the results obtained by OrsquoLeary et aland Woode et al [20 39]mdashthe former demonstrating thatreserpine at the dose used produced a 93 and 95 depletionof cortical noradrenaline and dopamine content respectivelyand a 78 depletion of 5-HT To inhibit synthesis as wellas deplete vesicular pools of noradrenaline and dopaminemice were pretreated with both reserpine and 120572-methyldopaResults were similar to effects observed when mice weretreated with reserpine alone The work published by OrsquoLearyet al [20] indicated that when reserpine was combined with120572-methyl para-tyrosine AMPT (NE and DA biosyntheticinhibitor) a depletion of cortical DA (95) NE (97) and 5-HT (78) was observedThe combination had only a modesteffect on NE and DA but failed to affect 5-HT Though 120572-methyldopa was used instead of the AMPT used by OrsquoLearyand colleagues the results from the combined effect ofreserpine and 120572-methyldopa did not differ significantly fromwhen reserpine was used alone Amore recent publication byWoode et al [39] used 120572-methyldopa and similar results wasobserved These results demonstrate that the antidepressanteffect of MOE may not be dependent on noradrenergicneurotransmission

Both clinical and preclinical studies support the antide-pressant activity of antagonists on functional glycineNMDAreceptor complex These compounds are thought to havelower side effect profiles compared to the competitive and

noncompetitive NMDA antagonists The effect of MOE onglutamatergic neurotransmission was assessed by pretreatingmice with d-serine (DS) a full agonist on glycineNMDAreceptors or d-cycloserine (DCS) a partial agonist onthese receptors In both the TST and FST DS reversedthe decline in immobility by MOE and fluoxetine but DCSpretreatment potentiated the decline demonstrating thatMOE may be acting as an antagonist on the glycineNMDAreceptor complex In contrast the decrease in immobilityof desipramine was reversed by DS but DCS had no effecton it This suggests that the antidepressant effect of bothserotonin and noradrenaline-based compounds depends onthe inhibition of the glycineNMDA receptor complex butthe enhancement of antidepressant activity depends on theserotoninergic pathway and not the noradrenaline pathway[40] This explains why the antidepressant effect of theextract fluoxetine and desipramine was abolished by d-serine but only the effect of the extract and fluoxetine(which act via serotoninergic pathway) was potentiated by d-cycloserine Moreover MOE increased curling score in theTST slightly (suggestive of opioidergic activity) though notsignificant Pretreatment with DCS significantly increasedcurling score of MOE but did not affect both FLX and DSPtreated groups DS pretreatment partially inhibited pedalingbehaviour byMOEbut totally in FLX andDSP treated groupsDCS pretreatment also inhibited pedaling behaviour byMOEand DSP but not FLX According to Berrocoso et al [41]opioids decrease immobility score while increasing curlingbehaviour in mice This suggests that the extract on its ownmay have little effect on opioidergic activity but may interact

ISRN Pharmacology 9

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

daggerdaggerdagger

daggerdaggerdagger

daggerdaggerdagger

Ctrl MOE FLX DSP

50

40

30

20

10

0

Imm

obili

ty ti

me (

s)

(a)

Ctrl MOE FLX DSP

50

40

30

20

10

0

Imm

obili

ty ti

me (

s)

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

daggerdaggerdagger

daggerdaggerdagger

(b)

lowast

lowastlowast

lowastlowastlowast

dagger

daggerdagger

30

25

20

15

10

5

0

Peda

lling

tim

e (s)

Ctrl MOE FLX DSP

(c)

lowast

lowast

lowast

daggerdaggerdagger

30

25

20

15

10

5

0

Peda

lling

tim

e (s)

Ctrl MOE FLX DSP

(d)

Ctrl MOE FLX DSP

UntreatedD-serine-treated

60

Curli

ng ti

me (

s)

50

40

30

20

10

0

lowastlowastlowast

daggerdagger

(e)

daggerdagger

Ctrl MOE FLX DSP

Untreated

60

Curli

ng ti

me (

s)

50

40

30

20

10

0

lowastlowastlowast

lowastlowast

D-cycloserine-treated

(f)

Figure 6 Effects of d-serine (DS) or d-cycloserine (DCS) pretreatment on (a b) mean immobility count (c d) pedalling count and (e f)curling count of extractMOE (100mg kgminus1) fluoxetine FLX (10mg kgminus1) anddesipramineDSP (10mg kgminus1) treatment in the tail suspensiontest (TST) Data are presented as Means plusmn SEM significantly different from control lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 by Newman Keulrsquos testSignificant difference between treatments dagger119875 lt 005 daggerdagger119875 lt 001 and daggerdaggerdagger119875 lt 0001

10 ISRN Pharmacology

Imm

obili

ty ti

me (

s)

60

50

40

30

20

10

0

Ctrl MOE FLX DSP

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

(a)

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

Imm

obili

ty ti

me (

s)

60

50

40

30

20

10

0

Ctrl MOE FLX DSP

daggerdagger

(b)

Swim

min

g tim

e (s)

80

60

40

20

0

Ctrl MOE FLX DSP

lowastlowastlowast lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

daggerdaggerdagger

(c)

Swim

min

g tim

e (s)

80

60

40

20

0

Ctrl MOE FLX DSP

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

daggerdaggerdagger

daggerdagger

lowastlowast

(d)

Clim

bing

tim

e (s)

50

40

30

20

10

8

6

4

2

0

lowastlowast

UntreatedD-serine-treated

lowast

lowast

Ctrl MOE FLX DSP

(e)

Clim

bing

tim

e (s)

50

40

30

20

10

8

6

4

2

0

lowastlowastlowastlowastlowastlowast

UntreatedD-cycloserine-treated

lowast

lowast

dagger

Ctrl MOE FLX DSP

(f)

Figure 7 Effects of d-serine (DS) or d-cycloserine (DCS) pretreatment on (a b) mean immobility count (c d) swimming count and (ef) climbing count of extract MOE (100mg kgminus1) fluoxetine FLX (10mg kgminus1) and desipramine DSP (10mg kgminus1) treatment in the forcedswimming test (FST) Data are presented as means plusmn SEM significantly different from control lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 by Newman Keulrsquostest Significant difference between treatments dagger119875 lt 005 daggerdagger119875 lt 001 and daggerdaggerdagger119875 lt 0001

ISRN Pharmacology 11

with opioid receptors when combined with DCS In the FSTMOE and FLX unlike DSP increased swimming behaviourwhich is sensitive to selective serotonin reuptake inhibitors(SSRIs) and 5HT agonists [22 42] This behavior exhibitedbyMOE and fluoxetine-treated mice was inhibited by DS butincreased byDCS pretreatment further supporting the theorythat antidepressant effect of serotonin based drugs dependson the inhibition of the glycineNMDA receptor complexand the enhancement of antidepressant activity dependson the serotoninergic pathway [40] Climbing scores weredecreased by both MOE and FLX and this was not affectedby both DS and DCS pretreatment This confirms theirlack of noradrenergic activity DSP a selective noradrenergicreuptake inhibitor on the contrary increased climbing scorewhich was unaffected by DCS pretreatment but decreasedby DS It is worth mentioning that the extract fluoxetinedesipramine alone or their combination with either d-serineor d-cycloserine did not impair motor coordination Thusthe behavioural effect observed can be attributed to drugtreatment alone

5 Conclusion

The present study shows that Mallotus oppositifolius hasantidepressant-like effect in mice and this may be mediatedvia enhancement of serotoninergic neurotransmission andinhibition of glycineNMDA receptor complex activationThe antidepressant effect of the extract may be devoid ofnoradrenergic mechanisms

Conflict of Interests

The authors declare that they have no conflict of interests

References

[1] P V Holmes ldquoRodent models of depression reexaminingvalidity without anthropomorphic inferencerdquo Critical Reviewsin Neurobiology vol 15 no 2 pp 143ndash174 2003

[2] J Alonso M C Angermeyer S Bernert et al ldquoPrevalence ofmental disorders in Europe results from the European Study ofthe Epidemiology ofMental Disorders (ESEMeD) projectrdquoActaPsychiatrica Scandinavica Supplement vol 109 no 420 pp 21ndash27 2004

[3] T B Ustun J L Ayuso-Mateos S Chatterji C Mathers and CJ L Murray ldquoGlobal burden of depressive disorders in the year2000rdquo British Journal of Psychiatry vol 184 pp 386ndash392 2004

[4] H Gilmour and S B Patten ldquoDepression and work impair-mentrdquo Health Reports vol 18 no 1 pp 9ndash22 2007

[5] E Poleszak B Szewczyk E Kedzierska P Wlaz A Pilcand G Nowak ldquoAntidepressant- and anxiolytic-like activity ofmagnesium in micerdquo Pharmacology Biochemistry and Behaviorvol 78 no 1 pp 7ndash12 2004

[6] P Skolnick P Popik and R Trullas ldquoGlutamate-based antide-pressants 20 years onrdquo Trends in Pharmacological Sciences vol30 no 11 pp 563ndash569 2009

[7] J F Cryan A Markou and I Lucki ldquoAssessing antidepressantactivity in rodents recent developments and future needsrdquoTrends in Pharmacological Sciences vol 23 no 5 pp 238ndash2452002

[8] E J Nestler M Barrot R J DiLeone A J Eisch S J Gold andLMMonteggia ldquoNeurobiology of depressionrdquoNeuron vol 34no 1 pp 13ndash25 2002

[9] R Trullas and P Skolnick ldquoFunctional antagonists at theNMDA receptor complex exhibit antidepressant actionsrdquo Euro-pean Journal of Pharmacology vol 185 no 1 pp 1ndash10 1990

[10] M Siwek D Dudek I A Paul et al ldquoZinc supplementationaugments efficacy of imipramine in treatment resistant patientsa double blind placebo-controlled studyrdquo Journal of AffectiveDisorders vol 118 no 1ndash3 pp 187ndash195 2009

[11] R M Berman A Cappiello A Anand et al ldquoAntidepressanteffects of ketamine in depressed patientsrdquo Biological Psychiatryvol 47 no 4 pp 351ndash354 2000

[12] C A Zarate Jr N E Brutsche L Ibrahim et al ldquoReplicationof Ketaminersquos antidepressant efficacy in bipolar depression arandomized controlled add-on trialrdquo Biological Psychiatry vol71 no 11 pp 939ndash946 2012

[13] W-L Zhu S-J Wang M-M Liu et al ldquoGlycine siteN-methyl-D-aspartate receptor antagonist7-CTKA producesrapid antidepressant-like effects in male ratsrdquo Journal of Psychi-atry amp Neuroscience vol 38 no 5 pp 306ndash316 2013

[14] S Akhondzadeh and S H Abbasi ldquoHerbal medicine inthe treatment of Alzhelmerrsquos diseaserdquo American Journal ofAlzheimerrsquos Disease and other Dementias vol 21 no 2 pp 113ndash118 2006

[15] D P Briskin ldquoMedicinal plants and phytomedicines Linkingplant biochemistry and physiology to human healthrdquo PlantPhysiology vol 124 no 2 pp 507ndash514 2000

[16] R M Darwish and T A Aburjai ldquoEffect of ethnomedicinalplants used in folklore medicine in Jordan as antibiotic resis-tant inhibitors on Escherichia colirdquo BMC Complementary andAlternative Medicine vol 10 article 9 2010

[17] NRC Guideforthe Careand Useof Laboratory Animals TheNational Academies Press 1996

[18] R D Porsolt M Le Pichon and M Jalfre ldquoDepression a newanimal model sensitive to antidepressant treatmentsrdquo Naturevol 266 no 5604 pp 730ndash732 1977

[19] L Steru R Chermat B Thierry and P Simon ldquoThe tailsuspension test a new method for screening antidepressants inmicerdquo Psychopharmacology vol 85 no 3 pp 367ndash370 1985

[20] O F OrsquoLeary A J Bechtholt J J Crowley T E Hill M EPage and I Lucki ldquoDepletion of serotonin and catecholaminesblock the acute behavioral response to different classes ofantidepressant drugs in the mouse tail suspension testrdquo Psy-chopharmacology vol 192 no 3 pp 357ndash371 2007

[21] P L M van Giersbergen E van Duinkerken C G J SweepV M Wiegant J M van Ree and W de Jong ldquo120572-Methyldopainduces a naltrexone-insensitive antinociception and hypo-motility in ratsrdquo British Journal of Pharmacology vol 99 no 3pp 467ndash472 1990

[22] J F Cryan M E Page and I Lucki ldquoDifferential behav-ioral effects of the antidepressants reboxetine fluoxetine andmoclobemide in a modified forced swim test following chronictreatmentrdquo Psychopharmacology vol 182 no 3 pp 335ndash3442005

[23] B Petit-Demouliere F Chenu and M Bourin ldquoForced swim-ming test in mice a review of antidepressant activityrdquo Psy-chopharmacology vol 177 no 3 pp 245ndash255 2005

[24] P L Delgado H L Miller R M Salomon et al ldquoTryptophan-depletion challenge in depressed patients treated withdesipramine or fluoxetine implications for the role of

12 ISRN Pharmacology

serotonin in the mechanism of antidepressant actionrdquoBiological Psychiatry vol 46 no 2 pp 212ndash220 1999

[25] A L Eckeli F Dach and A L S Rodrigues ldquoAcute treatmentswith GMP produce antidepressant-like effects in micerdquo Neu-roReport vol 11 no 9 pp 1839ndash1843 2000

[26] E C Gavioli CW Vaughan GMarzola et al ldquoAntidepressant-like effects of the nociceptinorphanin FQ receptor antago-nist UFP-101 new evidence from rats and micerdquo Naunyn-Schmiedebergrsquos Archives of Pharmacology vol 369 no 6 pp547ndash553 2004

[27] M E Page M J Detke A Dalvi L G Kirby and I LuckildquoSerotonergic mediation of the effects of fluoxetine but notdesipramine in the rat forced swimming testrdquo Psychopharma-cology vol 147 no 2 pp 162ndash167 1999

[28] M E Page and I Lucki ldquoEffects of acute and chronic reboxetinetreatment on stress-inducedmonoamine efflux in the rat frontalcortexrdquo Neuropsychopharmacology vol 27 no 2 pp 237ndash2472002

[29] F P Bymaster W Zhang P A Carter et al ldquoFluoxetinebut not other selective serotonin uptake inhibitors increasesnorepinephrine and dopamine extracellular levels in prefrontalcortexrdquo Psychopharmacology vol 160 no 4 pp 353ndash361 2002

[30] D T Chau P V Rada K Kim R A Kosloff and B G HoebelldquoFluoxetine alleviates behavioral depression while decreasingacetylcholine release in the nucleus accumbens shellrdquoNeuropsy-chopharmacology vol 36 no 8 pp 1729ndash1737 2011

[31] S J Corne R W Pickering and B T Warner ldquoA methodfor assessing the effects of drugs on the central actions of5-hydroxytryptaminerdquo British Journal of Pharmacology andChemotherapy vol 20 pp 106ndash120 1963

[32] S Schreiber and C G Pick ldquoFluoxetine for blepharospasminteraction of serotonin and dopaminerdquo Journal of Nervous andMental Disease vol 183 no 11 pp 719ndash721 1995

[33] W D Essman A Singh and I Lucki ldquoSerotonergic propertiesof cocaine effects on a 5-HT2 receptor-mediated behavior andon extracellular concentrations of serotonin and dopaminerdquoPharmacology Biochemistry and Behavior vol 49 no 1 pp 107ndash113 1994

[34] L-F Xu W-J Chu X-Y Qing et al ldquoProtopine inhibits sero-tonin transporter and noradrenaline transporter and has theantidepressant-like effect in mice modelsrdquoNeuropharmacologyvol 50 no 8 pp 934ndash940 2006

[35] GWDeMuth and SHAckerman ldquo120572-Methyldopa and depres-sion a clinical study and review of the literaturerdquo AmericanJournal of Psychiatry vol 140 no 5 pp 534ndash538 1983

[36] J Ji J L Mcdermott and D E Dluzen ldquoSex differences inK+-evoked striatal dopamine output from superfused striataltissue fragments of reserpine-treated CD-1 micerdquo Journal ofNeuroendocrinology vol 19 no 9 pp 725ndash731 2007

[37] R R Metzger J M Brown V Sandoval et al ldquoInhibitoryeffect of reserpine ondopamine transporter functionrdquoEuropeanJournal of Pharmacology vol 456 no 1ndash3 pp 39ndash43 2002

[38] M Fukui R M Rodriguiz J Zhou et al ldquoVmat2 heterozygousmutant mice display a depressive-like phenotyperdquo Journal ofNeuroscience vol 27 no 39 pp 10520ndash10529 2007

[39] E Woode E Boakye-Gyasi N Amidu C Ansah and MDuwiejua ldquoAnxiolytic and antidepressant effects of a leafextract ofPalisota hirsutaK Schum (Commelinaceae) inmicerdquoInternational Journal of Pharmacology vol 6 no 1 pp 1ndash172010

[40] E Poleszak P Wlaz B Szewczyk et al ldquoA complexinteraction between glycineNMDA receptors andserotonergicnoradrenergic antidepressants in the forcedswim test in micerdquo Journal of Neural Transmission vol 118 no11 pp 1535ndash1546 2011

[41] E Berrocoso K Ikeda I Sora et al ldquoActive behavioursproduced by antidepressants and opioids in the mouse tailsuspension testrdquoThe International Journal of Neuropsychophar-macology vol 61 no 1 pp 151ndash162 2012

[42] J F Cryan and I Lucki ldquoAntidepressant-like behavioral effectsmediated by 5-hydroxytryptamine(2C) receptorsrdquo Journal ofPharmacology andExperimentalTherapeutics vol 295 no 3 pp1120ndash1126 2000

Submit your manuscripts athttpwwwhindawicom

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Pharmaceutics

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MEDIATORSINFLAMMATION

of

2 ISRN Pharmacology

study investigated the effect of the hydroalcoholic leaf extractof the plant in acute antidepressant modelsmdashthe forcedswim (FST) and tail suspension tests (TST) The effectsof the extract on the monoaminergic system (serotoninand noradrenaline) as well as the glycineNMDA receptorcomplex were investigated in order to elucidate the possiblemechanism(s) of action of the extract

2 Materials

Leaves of the plantMallotus oppositifoliuswere collected fromthe wild around the Kwame Nkrumah University of Scienceand Technology (KNUST) Kumasi Ghana (6∘4110158406410158401015840N1∘33101584042810158401015840W) and authenticated at the Department of HerbalMedicine of the Faculty of Pharmacy and Pharmaceuti-cal Sciences KNUST Kumasi where a voucher specimen(KNUSTFP03509) has been deposited After air-drying for7 days the leaves were pulverized with a hammer-mill andthe powder extracted by cold maceration using 70 (vv)ethanol in water over a period of 72 h The resulting extractwas concentrated under moderate temperature (60∘C) andpressure to a syrupy mass on a rotary evaporator The syrupymass was then dried to a dark brown semisolid mass usingwater bath and kept in a desiccator till it was ready to be usedThe final yield was 95 (ww) This is subsequently referredto asMallotus oppositifolius extract (MOE) or extract

21 Animals Male ICRmice were obtained from and housedat the animal facility of the Department of PharmacologyKNUST Kumasi GhanaThe animals were housed in groupsof five in stainless steel cages (34times47times18 cm) with soft woodshavings as bedding fed with normal commercial pellet diet(GAFCO Tema) given water ad libitum and maintainedunder laboratory conditions All animals used in these studieswere treated in accordance with the Guide for the Careand Use of Laboratory Animals [17] and experiments wereapproved by the College Ethics Committee

22 Chemicals Fluoxetine hydrochloride (Prozac) wasfrom Eli Lilly and Co Basingstoke England Imipraminehydrochloride (Tofranil) from Mallinckrodt Pharmaceuti-cals Ireland Desipramine hydrochloride d-serine d-cycloserine 120572-methyldopa reserpine and para-chloro-phenylalanine were purchased from Sigma-Aldrich Inc StLouis MO USA

23 Forced Swimming Test (FST) The FST was based on thatdescribed by Porsolt et al [18] Mice were divided into tengroups of five animals each and received the vehicle (water)extract (10 30 or 100mg kgminus1 po) or the standard referencedrugs fluoxetine (3 10 or 30mg kgminus1 po) imipramine (310 or 30mg kgminus1 po) One hour after oral administration ofthe test compoundsmicewere gently placed individually intotransparent cylindrical polyethylene tanks (25 cmhigh 10 cminternal diameter) containing water (25 to 28∘C) up to a levelof 20 cm and left there for 5min Each session was recordedby a video camera suspended approximately 100 cm abovethe cylinders An observer scored the duration of immobility

(when mouse floated upright in the water and made onlysmall movements to keep its head above water) during thelast 5min test from the videotapes with the aid of the publicdomain software JWatcher Version 10 (University of Cali-fornia Los Angeles USA andMacquarie University SydneyAustralia available at httpwwwjwatcheruclaedu)

24 Tail Suspension Test The TST was carried out as pre-viously described by Steru et al [19] Mice were allowed toacclimatize to the room for 35ndash4 h before the test Groupsof ten mice were treated with MOE (10 30 or 100mg kgminus1po) fluoxetine (3 10 or 30mg kgminus1 po) and imipramine(3 10 or 30mg kgminus1 po) or vehicle One hour after oraladministration of the test compoundsmicewere individuallysuspended by the tail from a horizontal bar (distance fromfloor = 30 cm) using adhesive tape (distance from tip of tail= 1 cm) Duration of immobility defined as the absence ofall movement except for those required for respiration wasrecorded by an observer for 5min from video recordingsof the test as described above for forced swimming testMice that climbed up on their tails during the test sessionwere gently pulled down and testing continued Mice thatcontinued to climb their tails were excluded from the study

25 Involvement of Noradrenergic Systems Mice were pre-treatedwith reserpine andor120572-methyldopa (120572-MD) in orderto investigate the possible role of noradrenergic system inthe actions of MOE [20] The doses of 120572-MD and reserpinewere chosen on the basis of work done by others [20 21] Todeplete newly synthesized pools of noradrenaline (NE) anddopamine (DA) mice were treated with a single dose of 120572-MD (400mg kgminus1 ip) 35 hours before behavioural testingTo deplete vesicular pools of NE and DA mice were treatedwith a single dose of reserpine (1mg kgminus1 sc) 24 h beforebehavioral testing In an effort to deplete both the vesicularand cytoplasmic pools of NE and DA mice were pretreatedwith a combination of reserpine (1mg kgminus1 sc 24 h beforebehavioral testing) and 120572-MD (200mg kgminus1 ip 35 hoursbefore behavioral testing) respectively

26 Involvement of Serotoninergic Systems Mice weregrouped into groups of five (5) forming ten (20) groupspCPA (200mg kgminus1 ip) was administered once daily for3 consecutive days to some of the animals On the fourthday group 1 received saline without pretreatment group 2received pCPA after pretreatment groups 3 to 5 receivedMOE (10 30 and 100mg kgminus1) without pretreatment groups6 to 8 received MOE (10 30 and 100mg kgminus1 po) afterpretreatment groups 9 to 11 received fluoxetine (3 10 and30mg kgminus1 po) alone groups 12 to 14 received fluoxetine(3 10 and 30mg kgminus1 po) after pretreatment groups 15ndash17received imipramine (3 10 and 30mg kgminus1 po) aloneand finally groups 18ndash20 received imipramine (3 10 and30mg kgminus1 po) after pretreatment After the tail suspensionsessions mice were taken through the modified forcedswimming test The modified forced swimming test followedthe same procedure described above except that the depth of

ISRN Pharmacology 3

water was changed to 20 cm For tail suspension immobilityperiod was scored whilst for the modified swimming testmean immobility counts mean swimming counts and meanclimbing counts were scored

27 Involvement of GlycineNMDA Neurotransmission Micewere divided into 2 groups A and B Groups A and B werefurther subdivided into 6 groups each (119899 = 8) Brieflyfive groups of mice from group A received d-cycloserine(25mg kgminus1 ip) and 30min after the first three groupsreceived an oral dose of the extract (10ndash100mg kgminus1) withthe last two groups receiving either fluoxetine (10mg kgminus1)or desipramine (10mg kgminus1 ip) The sixth group receivedonly d-cycloserine Again five groups of mice from groupB received d-serine (600mg kgminus1) and 30min after thefirst three groups received an oral dose of the extract (10ndash100mg kgminus1) with the last two groups receiving either flu-oxetine (10mg kgminus1 po) or desipramine (10mg kgminus1 ip)The sixth group from group B received only d-serine Theforced swim and tail suspension tests were used as describedabove to investigate the antidepressant mechanism Pedallingbehaviour was defined as the continuous movement of thepaw of the mice without moving the body while curling wasdefined as the raising of the head of the mouse towards itshind paws

28 Statistics GraphPad Prism for Windows version 403(GraphPad Software San Diego CA USA) was used forall data and statistical analyses 119875 lt 005 was consideredstatistically significant In all the tests a sample size of tenanimals (119899 = 10) were used The time-course curves weresubjected to two-way (treatment times time) repeated measuresanalysis of variance (ANOVA) with Bonferronirsquos post hoc testTotal immobility time distance travelled and time takento find the hidden platform and change in weight for eachtreatment were calculated in arbitrary unit as the area underthe curve (AUC) Differences in AUCs were analysed byANOVA followed by Newman Keulsrsquo post hoc test

3 Results

31 Forced Swimming and Tail Suspension Tests MOE (10ndash100mg kgminus1 po) administered 60min before the test periodsignificantly decreased the frequency of immobility (119865

319

=

2147 119875 lt 0001) (Figure 1(a)) and immobility periods ofmice (119865

319

= 1434 119875 lt 0001) (Figure 1(d)) in a dosedependent manner in the FST In the TST both frequency(119865654

= 0486 119875 = 08159) (Figures 2(a) 2(b) and 2(c))and duration (119865

652

= 2557 119875 lt 0001) (Figures 2(d)2(e) and 2(f)) of immobility decreased indicating significantantidepressant activity

32 Involvement of Noradrenergic Mechanisms Pretreat-ment with reserpine (1mg kgminus1 sc) alone 120572-methyldopa(400mg kgminus1 po) alone or a concomitant administration ofreserpine (1mg kgminus1 sc) and 120572-methyldopa (200mg kgminus1po) did not reverse the decline in immobility caused by

the extract MOE (10ndash100mg kgminus1 po) in the forced swimtest (FST) (Figures 3(a) 3(d) and 3(g)) Results obtainedfor fluoxetine-treated groups (FLX) (3ndash30mg kgminus1 po) weresimilar to that of the extract-treated groups (Figures 3(b)3(e) and 3(h)) In contrast the antidepressant effect ofimipramine (IMI) was reversed by either reserpine alone120572-methyldopa alone or a concomitant administration ofreserpine and 120572-methyldopa (Figures 3(c) 3(f) and 3(i))

33 Involvement of Serotoninergic Mechanism Pretreatmentof mice with pCPA (200mg kgminus1) abolished the antidepres-sant effect ofMOE (10ndash100mg kgminus1 po) and fluoxetine FLX(3ndash30mg kgminus1 po) but not imipramine IMI (3ndash30mg kgminus1po) in the FST The mean counts for immobility (119865

732

=

1463 119875 lt 00001) (Figure 4(a)) swimming (119865732

= 4474119875 lt 00001) (Figure 4(d)) and climbing (119865

732

= 1121 119875 =03742) (Figure 4(g)) in the extract-treated group after pCPApretreatment did not show any difference when comparedwith the control Similar results as above were observed forFLX-treated groups but not imipramine (Figures 4(b)-4(c)4(e)-4(f) and 4(h)-4(i))

In an attempt to investigate the possible involvementof 5-HT

2A receptor activation in the antidepressant actionof the extract mice were given 5-hydroxytryptophan afterextract pretreatment to induced head twitch responses Itwas observed from the time course curve that the extractas well as fluoxetine increased the head twitch responsessignificantly for the period of 30 minutes (Figures 5(a) and5(c)) Response peaked after 15 minutes One-way ANOVAfollowed by Newman Keulsrsquo test of the areas under the curve(AUCs) showed a dose dependent increase in the head twitchresponse for both extract and fluoxetine (Figures 5(b) and5(d))

34 Involvement of GlycineNMDA Receptor Complex In theTST MOE (100mg kgminus1 po) fluoxetine FLX (10mg kgminus1po) and desipramine DSP (10mg kgminus1 ip) exhibited sig-nificant antidepressant effect by decreasing mean immobilityscore which was reversed by d-serine DS (600mg kgminus1 ip)pretreatment (Figure 6(a)) Pretreatment with d-cycloserineDCS (25mg kgminus1 ip) potentiated the effect of MOE andFLX (but not DSP) by further decreasing mean immobilityscore (Figure 6(b)) MOE alone did not affect curling scoreand this was not changed by DS pretreatment (Figure 6(e))FLX and DSP alone caused slight increase in the curlingscore which was reversed by DS Pretreatment with DCSsignificantly increased curling score of MOE but caused onlya modest increase in both FLX and DSP treated groups(Figure 6(f)) MOE DS DCS FLX and DSP alone increasedswinging score DS pretreatment partially inhibited swingingbehaviour byMOE but totally in FLX andDSP treated groups(Figure 6(c)) DCS pretreatment also inhibited swingingbehaviour by MOE and DSP but not FLX (Figure 6(d))

In the forced swim test MOE FLX and DSP decreasedimmobility score and this was reversed by DS pretreatment(Figure 7(a)) Pretreatment with DCS potentiated the effectof MOE and FLX (but not DSP) by further decreasing

4 ISRN Pharmacology

Freq

uenc

y14

12

10

8

6

4

2

0

Ctrl 10 30 100

lowastlowastlowastlowast lowastlowastlowast

lowastlowastlowast

MOE (mg kgminus1)

(a)

3 10 30

lowastlowastlowast

lowastlowastlowastlowastlowastlowast lowastlowastlowastlowastlowastlowast

lowastlowastlowast

FLX (mg kgminus1)

(b)

3 10 30

lowastlowast

lowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

daggerdaggerdagger

daggerdaggerdagger

daggerdaggerdagger

IMI (mg kgminus1)

(c)

MobilityImmobility

Dur

atio

n (s

)

350

300

250

200

150

100

50

0

daggerdaggerdaggerdaggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

Ctrl 10 30 100

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

MOE (mg kgminus1)

(d)

daggerdaggerdagger daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowastlowastlowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

lowastlowastlowast

3 10 30

MobilityImmobility

FLX (mg kgminus1)

(e)

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

3 10 30

MobilityImmobility

IMI (mg kgminus1)

(f)

Figure 1 Effects of extract MOE (10ndash100mg kgminus1) fluoxetine FLX (3ndash30mg kgminus1) and imipramine IMI (3ndash30mg kgminus1) treatment on (ab and c) the frequency of mobility and immobility and (d e and f) duration of mobility and immobility in the FST Data are presented asgroup means plusmn SEM significantly different from control lowastlowastlowast119875 lt 0001 lowastlowast119875 lt 001 (one-way ANOVA followed by Newman Keulsrsquo test)daggerdaggerdagger

119875 lt 0001 comparison between effect and dose (two-way ANOVA followed by Bonferronirsquos test)

immobility score (Figure 7(b)) MOE and FLX unlike DSPincreased swimming behaviour which was inhibited by DSbut increased by DCS pretreatment (Figures 7(c) and 7(d))Climbing scores were decreased by both MOE and FLX andthis was not affected by both DS and DCS pretreatment(Figures 7(e) and 7(f)) DSP on the contrary increasedclimbing score which was unaffected by DCS pretreatmentbut decreased by DS

4 Discussion

Results of the study demonstrated that MOE has significantantidepressant effect in both the forced swimming and thetail suspension tests In both animal models percentageimmobility and frequency of immobility were decreased byextract treatment Reduction in immobility has been used asthe primary index for antidepressant effect of test substancesin these modelsmdashalmost all antidepressants in clinical use

induce a decrease in immobility in rodents whilst other drugsfail to give the same response [22 23]

Preclinical and clinical studies suggest that depletionof a monoamine implicated in depression pathophysiologymay abolish the antidepressant effect of a substance if thesubstance depends on that particular monoamine for itsantidepressant effect [20 24]Hencewhen 5-HTwas depletedby pretreating mice for 3 days with the tryptophan hydrox-ylase inhibitor para-chlorophenylalanine (pCPA) the effectsof drugs that act by enhancing 5-HT neurotransmission wereabolished [25 26] while those that act on noradrenergicpathways were not affected [26ndash28] The inhibition of theantidepressant effect of MOE by pCPA in both TST andFST suggests that its antidepressant effect is dependenton enhancement of serotoninergic neurotransmission Thelack of antidepressant effect of fluoxetine in pCPA-treatedmice is consistent with the hypothesis that fluoxetine elicitsits acute behavioural effects by increasing extracellular 5-HT after blockade of the serotonin transporter [29] The

ISRN Pharmacology 5

Freq

uenc

y10

8

6

4

2

0

Ctrl 10 30 100

lowast

MOE (mg kgminus1)

(a)

10 303

lowast

lowast

FLX (mg kgminus1)

(b)

10 303

lowast

lowastlowast

IMI (mg kgminus1)

(c)

Dur

atio

n (s

)

350

300

250

200

150

100

50

0

MobilityImmobility

Ctrl 10 30 100

daggerdagger daggerdagger

daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast lowastlowastlowast lowastlowastlowast

lowastlowastlowast lowastlowastlowast

lowastlowastlowast

MOE (mg kgminus1)

(d)

MobilityImmobility

10 303

daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

FLX (mg kgminus1)

(e)

MobilityImmobility

10 303

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

IMI (mg kgminus1)

(f)

Figure 2 Effect of the extract MOE (10 30 and 100mg kgminus1) fluoxetine FLX (3 10 and 30mg kgminus1) and imipramine IMI (3 10 and30mg kgminus1) treatment on the (a b and c) frequency of mobility and immobility and (d e and f) duration of mobility and immobility in theTST Data are presented as group means plusmn SEM lowastlowastlowast119875 lt 0001 lowastlowast119875 lt 001 compared to vehicle-treated group (one-way ANOVA followedby Newman Keulsrsquo test) daggerdaggerdagger119875 lt 0001 comparison effect and dose (two-way ANOVA followed by Bonferronirsquos test)

extract and fluoxetine increased swimming score which wasreversed with pCPA pretreatment further supporting theiraction on the serotoninergic system [27 30] Both MOE andfluoxetine did not affect mean climbing score suggesting thattheir behavioural effect may not depend on noradrenergicpathways

Further evidence suggesting that the extract enhances 5-HTneurotransmissionwas derived from its ability to increasehead twitch responses induced by 5-HTP The head twitchresponse (HTR) in rodents induced by 5-hydroxytryptophan(5-HTP) a precursor of 5-HT [31] is considered as a specificbehavioural model for the activation of serotoninergic neu-ron specifically 5-HT

2A receptors [32]Thus it can be inferredthat MOE may be acting via direct or indirect activation of5-HT2A receptors Fluoxetine also increased the frequency of

HTRsThis result is consistentwith a number of studieswherefluoxetine elicited similar responses [33 34]

The present experiments also examined the role of nora-drenaline and dopamine in the acute behavioural effects of

the extract in the modified FST by using drugs that interferewith their neurotransmitter synthesis or release Depletionwith 120572-methyldopa an L-aromatic amino acid decarboxylaseinhibitor that inhibits the biosynthesis of catecholamines and5-HT [35] failed to attenuate the behavioural effects of MOEand fluoxetine while that of imipramine was abolished Thissuggests that MOE may not be affected by the biosynthesisof noradrenaline or dopamine Moreover when vesicularpools were depleted by reserpine the decrease in immobilityelicited by MOE or fluoxetine was not affected Here againthe effect of imipramine was attenuated Reserpine is anirreversible inhibitor of the vesicular monoamine transporter2 (VMAT-2) which is located primarily within the CNS andis responsible for transporting monoamines from the cyto-plasm into secretory vesicles [36 37] Treatment with reser-pine therefore leads to depletion of vesicular monoaminestoresmdashboth serotonin and noradrenaline [38] suggestingboth serotonin and noradrenaline might be important inthe antidepressant effects of imipramine The inability of

6 ISRN Pharmacology

Ctrl 10 30 100

lowastlowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowastIm

mob

ility

tim

e (s)

100

80

60

40

20

0

Untreated120572-MD-treated

MOE (mg kgminus1)

(a)

lowast

lowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowastlowastlowastlowast

Untreated

3 10 30

120572-MD-treated

FLX (mg kgminus1)

(b)

lowast

daggerdagger

daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

Untreated

3 10 30

120572-MD-treated

IMI (mg kgminus1)

(c)

lowastlowast

lowastlowast lowastlowastlowastlowastlowast

lowastlowastlowastlowastlowastlowast

UntreatedReserpinised

Ctrl 10 30 100

Imm

obili

ty ti

me (

s)

100

80

60

40

20

0

MOE (mg kgminus1)

(d)

lowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowast

3 10 30

UntreatedReserpinised

FLX (mg kgminus1)

(e)

lowast

daggerdaggerdagger

daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

3 10 30

UntreatedReserpinised

IMI (mg kgminus1)

(f)

daggerdagger

lowastlowastlowastlowastlowast

lowastlowastlowastlowastlowastlowastlowastlowastlowastlowastlowastlowast

Untreated

120

Imm

obili

ty ti

me (

s)

100

80

60

40

20

0

Ctrl 10 30 100

120572-MDres-treated

MOE (mg kgminus1)

(g)

lowast

lowastlowastlowast

lowastlowastlowast lowastlowastlowast

lowastlowastlowastlowastlowastlowast

3 10 30

Untreated120572-MDres-treated

FLX (mg kgminus1)

(h)

lowastlowast

daggerdaggerdaggerdaggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

3 10 30

Untreated120572-MDres-treated

IMI (mg kgminus1)

(i)

Figure 3 Effects of (andashc) reserpine alone (dndashf) 120572-methyldopa 120572-MD alone or (gndashi) both reserpine and 120572-methyldopa on duration ofimmobility of MOE (10ndash100mg kgminus1 po) fluoxetine (3ndash30mg kgminus1 po) and imipramine (3ndash30mg kgminus1 po) treatment in the FST Dataare presented as mean plusmn SEM of 5 animals significantly different from control lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 by one-way ANOVA followed byNewman Keulsrsquo test dagger119875 lt 005 daggerdagger119875 lt 001 and daggerdaggerdagger119875 lt 0001 significant difference between treatment and dose (two-way ANOVA withBonferroni post hoc test)

ISRN Pharmacology 7

Ctrl 10 30 100

Imm

obili

ty ti

me (

s)

60

40

50

20

10

30

0

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

MOE (mg kgminus1)

(a)

3 10 30

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

FLX (mg kgminus1)

(b)

3 10 30

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowast lowastlowastlowast

lowastlowastlowast

dagger

IMI (mg kgminus1)

(c)

Swim

min

g tim

e (s)

40

50

20

10

30

0

Ctrl 10 30 100

daggerdaggerdagger daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast lowastlowastlowast

lowastlowastlowast

MOE (mg kgminus1)

(d)

3 10 30

daggerdaggerdagger

daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

lowastlowast

FLX (mg kgminus1)

(e)

3 10 30

lowast

IMI (mg kgminus1)

(f)

Clim

bing

tim

e (s)

40

50

20

10

30

0

Ctrl 10 30 100

UntreatedPCPA-treated

MOE (mg kgminus1)

(g)

3 10 30

dagger

dagger

lowastlowastlowast

UntreatedPCPA-treated

FLX (mg kgminus1)

(h)

3 10 30

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

UntreatedPCPA-treated

IMI (mg kgminus1)

(i)

Figure 4 Effects of pCPA (200mg kgminus1) pretreatment on the (andashc) mean immobility counts (dndashf) swimming counts and (gndashi) climbingcounts of oral doses of extract MOE (10ndash100mg kgminus1) fluoxetine FLX (3ndash30mg kgminus1) and IMI (3ndash30mg kgminus1) treated groups in the FSTData are presented as mean plusmn SEM significantly different from control lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 by Newman Keulsrsquo test daggerdaggerdagger119875 lt 0001(two-way ANOVA followed by Bonferronirsquos post test comparison between drug treatment and dose)

8 ISRN Pharmacology

0

0

5

5

10

10

15

15

20

20

25

25

30

30

Time (min)

Ctrl

Ctrl

10 30 100

160

120

80

40

0

35lowastlowast

lowastlowastlowast

lowastlowastlowast

Num

ber o

f hea

d tw

itche

s

AUC

MOEMOEMOE10mg kgminus1

30mg kgminus1100mg kgminus1

(a)

0 5 10 15 20 25 30

Time (min)Ctrl

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

0

5

10

15

20

25

30

35

Num

ber o

f hea

d tw

itche

sFLX

FLXFLX

Ctrl 3 10 30

160

120

80

40

0

AUC

3mg kgminus110mg kgminus130mg kgminus1

(b)

Figure 5 Effect of MOE (10ndash100mg kgminus1 po) and fluoxetine (3ndash30mg kgminus1 po) on the time course curve of head twitch response test andtheir corresponding AUCs (a and b) in the same test represented as bar graphs Data was presented as mean plusmn SEM (119899 = 6) lowastlowastlowast119875 lt 0001lowastlowast

119875 lt 001 compared to vehicle-treated group (one-way ANOVA followed by Newman Keulsrsquo test)

reserpine pretreatment to reverse the antidepressant effectsof the extract and fluoxetine however seems to suggest thatreserpine does not affect vesicular storage of 5-HT to thesame extent as that of noradrenaline In fact this assertionis consistent with the results obtained by OrsquoLeary et aland Woode et al [20 39]mdashthe former demonstrating thatreserpine at the dose used produced a 93 and 95 depletionof cortical noradrenaline and dopamine content respectivelyand a 78 depletion of 5-HT To inhibit synthesis as wellas deplete vesicular pools of noradrenaline and dopaminemice were pretreated with both reserpine and 120572-methyldopaResults were similar to effects observed when mice weretreated with reserpine alone The work published by OrsquoLearyet al [20] indicated that when reserpine was combined with120572-methyl para-tyrosine AMPT (NE and DA biosyntheticinhibitor) a depletion of cortical DA (95) NE (97) and 5-HT (78) was observedThe combination had only a modesteffect on NE and DA but failed to affect 5-HT Though 120572-methyldopa was used instead of the AMPT used by OrsquoLearyand colleagues the results from the combined effect ofreserpine and 120572-methyldopa did not differ significantly fromwhen reserpine was used alone Amore recent publication byWoode et al [39] used 120572-methyldopa and similar results wasobserved These results demonstrate that the antidepressanteffect of MOE may not be dependent on noradrenergicneurotransmission

Both clinical and preclinical studies support the antide-pressant activity of antagonists on functional glycineNMDAreceptor complex These compounds are thought to havelower side effect profiles compared to the competitive and

noncompetitive NMDA antagonists The effect of MOE onglutamatergic neurotransmission was assessed by pretreatingmice with d-serine (DS) a full agonist on glycineNMDAreceptors or d-cycloserine (DCS) a partial agonist onthese receptors In both the TST and FST DS reversedthe decline in immobility by MOE and fluoxetine but DCSpretreatment potentiated the decline demonstrating thatMOE may be acting as an antagonist on the glycineNMDAreceptor complex In contrast the decrease in immobilityof desipramine was reversed by DS but DCS had no effecton it This suggests that the antidepressant effect of bothserotonin and noradrenaline-based compounds depends onthe inhibition of the glycineNMDA receptor complex butthe enhancement of antidepressant activity depends on theserotoninergic pathway and not the noradrenaline pathway[40] This explains why the antidepressant effect of theextract fluoxetine and desipramine was abolished by d-serine but only the effect of the extract and fluoxetine(which act via serotoninergic pathway) was potentiated by d-cycloserine Moreover MOE increased curling score in theTST slightly (suggestive of opioidergic activity) though notsignificant Pretreatment with DCS significantly increasedcurling score of MOE but did not affect both FLX and DSPtreated groups DS pretreatment partially inhibited pedalingbehaviour byMOEbut totally in FLX andDSP treated groupsDCS pretreatment also inhibited pedaling behaviour byMOEand DSP but not FLX According to Berrocoso et al [41]opioids decrease immobility score while increasing curlingbehaviour in mice This suggests that the extract on its ownmay have little effect on opioidergic activity but may interact

ISRN Pharmacology 9

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

daggerdaggerdagger

daggerdaggerdagger

daggerdaggerdagger

Ctrl MOE FLX DSP

50

40

30

20

10

0

Imm

obili

ty ti

me (

s)

(a)

Ctrl MOE FLX DSP

50

40

30

20

10

0

Imm

obili

ty ti

me (

s)

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

daggerdaggerdagger

daggerdaggerdagger

(b)

lowast

lowastlowast

lowastlowastlowast

dagger

daggerdagger

30

25

20

15

10

5

0

Peda

lling

tim

e (s)

Ctrl MOE FLX DSP

(c)

lowast

lowast

lowast

daggerdaggerdagger

30

25

20

15

10

5

0

Peda

lling

tim

e (s)

Ctrl MOE FLX DSP

(d)

Ctrl MOE FLX DSP

UntreatedD-serine-treated

60

Curli

ng ti

me (

s)

50

40

30

20

10

0

lowastlowastlowast

daggerdagger

(e)

daggerdagger

Ctrl MOE FLX DSP

Untreated

60

Curli

ng ti

me (

s)

50

40

30

20

10

0

lowastlowastlowast

lowastlowast

D-cycloserine-treated

(f)

Figure 6 Effects of d-serine (DS) or d-cycloserine (DCS) pretreatment on (a b) mean immobility count (c d) pedalling count and (e f)curling count of extractMOE (100mg kgminus1) fluoxetine FLX (10mg kgminus1) anddesipramineDSP (10mg kgminus1) treatment in the tail suspensiontest (TST) Data are presented as Means plusmn SEM significantly different from control lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 by Newman Keulrsquos testSignificant difference between treatments dagger119875 lt 005 daggerdagger119875 lt 001 and daggerdaggerdagger119875 lt 0001

10 ISRN Pharmacology

Imm

obili

ty ti

me (

s)

60

50

40

30

20

10

0

Ctrl MOE FLX DSP

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

(a)

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

Imm

obili

ty ti

me (

s)

60

50

40

30

20

10

0

Ctrl MOE FLX DSP

daggerdagger

(b)

Swim

min

g tim

e (s)

80

60

40

20

0

Ctrl MOE FLX DSP

lowastlowastlowast lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

daggerdaggerdagger

(c)

Swim

min

g tim

e (s)

80

60

40

20

0

Ctrl MOE FLX DSP

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

daggerdaggerdagger

daggerdagger

lowastlowast

(d)

Clim

bing

tim

e (s)

50

40

30

20

10

8

6

4

2

0

lowastlowast

UntreatedD-serine-treated

lowast

lowast

Ctrl MOE FLX DSP

(e)

Clim

bing

tim

e (s)

50

40

30

20

10

8

6

4

2

0

lowastlowastlowastlowastlowastlowast

UntreatedD-cycloserine-treated

lowast

lowast

dagger

Ctrl MOE FLX DSP

(f)

Figure 7 Effects of d-serine (DS) or d-cycloserine (DCS) pretreatment on (a b) mean immobility count (c d) swimming count and (ef) climbing count of extract MOE (100mg kgminus1) fluoxetine FLX (10mg kgminus1) and desipramine DSP (10mg kgminus1) treatment in the forcedswimming test (FST) Data are presented as means plusmn SEM significantly different from control lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 by Newman Keulrsquostest Significant difference between treatments dagger119875 lt 005 daggerdagger119875 lt 001 and daggerdaggerdagger119875 lt 0001

ISRN Pharmacology 11

with opioid receptors when combined with DCS In the FSTMOE and FLX unlike DSP increased swimming behaviourwhich is sensitive to selective serotonin reuptake inhibitors(SSRIs) and 5HT agonists [22 42] This behavior exhibitedbyMOE and fluoxetine-treated mice was inhibited by DS butincreased byDCS pretreatment further supporting the theorythat antidepressant effect of serotonin based drugs dependson the inhibition of the glycineNMDA receptor complexand the enhancement of antidepressant activity dependson the serotoninergic pathway [40] Climbing scores weredecreased by both MOE and FLX and this was not affectedby both DS and DCS pretreatment This confirms theirlack of noradrenergic activity DSP a selective noradrenergicreuptake inhibitor on the contrary increased climbing scorewhich was unaffected by DCS pretreatment but decreasedby DS It is worth mentioning that the extract fluoxetinedesipramine alone or their combination with either d-serineor d-cycloserine did not impair motor coordination Thusthe behavioural effect observed can be attributed to drugtreatment alone

5 Conclusion

The present study shows that Mallotus oppositifolius hasantidepressant-like effect in mice and this may be mediatedvia enhancement of serotoninergic neurotransmission andinhibition of glycineNMDA receptor complex activationThe antidepressant effect of the extract may be devoid ofnoradrenergic mechanisms

Conflict of Interests

The authors declare that they have no conflict of interests

References

[1] P V Holmes ldquoRodent models of depression reexaminingvalidity without anthropomorphic inferencerdquo Critical Reviewsin Neurobiology vol 15 no 2 pp 143ndash174 2003

[2] J Alonso M C Angermeyer S Bernert et al ldquoPrevalence ofmental disorders in Europe results from the European Study ofthe Epidemiology ofMental Disorders (ESEMeD) projectrdquoActaPsychiatrica Scandinavica Supplement vol 109 no 420 pp 21ndash27 2004

[3] T B Ustun J L Ayuso-Mateos S Chatterji C Mathers and CJ L Murray ldquoGlobal burden of depressive disorders in the year2000rdquo British Journal of Psychiatry vol 184 pp 386ndash392 2004

[4] H Gilmour and S B Patten ldquoDepression and work impair-mentrdquo Health Reports vol 18 no 1 pp 9ndash22 2007

[5] E Poleszak B Szewczyk E Kedzierska P Wlaz A Pilcand G Nowak ldquoAntidepressant- and anxiolytic-like activity ofmagnesium in micerdquo Pharmacology Biochemistry and Behaviorvol 78 no 1 pp 7ndash12 2004

[6] P Skolnick P Popik and R Trullas ldquoGlutamate-based antide-pressants 20 years onrdquo Trends in Pharmacological Sciences vol30 no 11 pp 563ndash569 2009

[7] J F Cryan A Markou and I Lucki ldquoAssessing antidepressantactivity in rodents recent developments and future needsrdquoTrends in Pharmacological Sciences vol 23 no 5 pp 238ndash2452002

[8] E J Nestler M Barrot R J DiLeone A J Eisch S J Gold andLMMonteggia ldquoNeurobiology of depressionrdquoNeuron vol 34no 1 pp 13ndash25 2002

[9] R Trullas and P Skolnick ldquoFunctional antagonists at theNMDA receptor complex exhibit antidepressant actionsrdquo Euro-pean Journal of Pharmacology vol 185 no 1 pp 1ndash10 1990

[10] M Siwek D Dudek I A Paul et al ldquoZinc supplementationaugments efficacy of imipramine in treatment resistant patientsa double blind placebo-controlled studyrdquo Journal of AffectiveDisorders vol 118 no 1ndash3 pp 187ndash195 2009

[11] R M Berman A Cappiello A Anand et al ldquoAntidepressanteffects of ketamine in depressed patientsrdquo Biological Psychiatryvol 47 no 4 pp 351ndash354 2000

[12] C A Zarate Jr N E Brutsche L Ibrahim et al ldquoReplicationof Ketaminersquos antidepressant efficacy in bipolar depression arandomized controlled add-on trialrdquo Biological Psychiatry vol71 no 11 pp 939ndash946 2012

[13] W-L Zhu S-J Wang M-M Liu et al ldquoGlycine siteN-methyl-D-aspartate receptor antagonist7-CTKA producesrapid antidepressant-like effects in male ratsrdquo Journal of Psychi-atry amp Neuroscience vol 38 no 5 pp 306ndash316 2013

[14] S Akhondzadeh and S H Abbasi ldquoHerbal medicine inthe treatment of Alzhelmerrsquos diseaserdquo American Journal ofAlzheimerrsquos Disease and other Dementias vol 21 no 2 pp 113ndash118 2006

[15] D P Briskin ldquoMedicinal plants and phytomedicines Linkingplant biochemistry and physiology to human healthrdquo PlantPhysiology vol 124 no 2 pp 507ndash514 2000

[16] R M Darwish and T A Aburjai ldquoEffect of ethnomedicinalplants used in folklore medicine in Jordan as antibiotic resis-tant inhibitors on Escherichia colirdquo BMC Complementary andAlternative Medicine vol 10 article 9 2010

[17] NRC Guideforthe Careand Useof Laboratory Animals TheNational Academies Press 1996

[18] R D Porsolt M Le Pichon and M Jalfre ldquoDepression a newanimal model sensitive to antidepressant treatmentsrdquo Naturevol 266 no 5604 pp 730ndash732 1977

[19] L Steru R Chermat B Thierry and P Simon ldquoThe tailsuspension test a new method for screening antidepressants inmicerdquo Psychopharmacology vol 85 no 3 pp 367ndash370 1985

[20] O F OrsquoLeary A J Bechtholt J J Crowley T E Hill M EPage and I Lucki ldquoDepletion of serotonin and catecholaminesblock the acute behavioral response to different classes ofantidepressant drugs in the mouse tail suspension testrdquo Psy-chopharmacology vol 192 no 3 pp 357ndash371 2007

[21] P L M van Giersbergen E van Duinkerken C G J SweepV M Wiegant J M van Ree and W de Jong ldquo120572-Methyldopainduces a naltrexone-insensitive antinociception and hypo-motility in ratsrdquo British Journal of Pharmacology vol 99 no 3pp 467ndash472 1990

[22] J F Cryan M E Page and I Lucki ldquoDifferential behav-ioral effects of the antidepressants reboxetine fluoxetine andmoclobemide in a modified forced swim test following chronictreatmentrdquo Psychopharmacology vol 182 no 3 pp 335ndash3442005

[23] B Petit-Demouliere F Chenu and M Bourin ldquoForced swim-ming test in mice a review of antidepressant activityrdquo Psy-chopharmacology vol 177 no 3 pp 245ndash255 2005

[24] P L Delgado H L Miller R M Salomon et al ldquoTryptophan-depletion challenge in depressed patients treated withdesipramine or fluoxetine implications for the role of

12 ISRN Pharmacology

serotonin in the mechanism of antidepressant actionrdquoBiological Psychiatry vol 46 no 2 pp 212ndash220 1999

[25] A L Eckeli F Dach and A L S Rodrigues ldquoAcute treatmentswith GMP produce antidepressant-like effects in micerdquo Neu-roReport vol 11 no 9 pp 1839ndash1843 2000

[26] E C Gavioli CW Vaughan GMarzola et al ldquoAntidepressant-like effects of the nociceptinorphanin FQ receptor antago-nist UFP-101 new evidence from rats and micerdquo Naunyn-Schmiedebergrsquos Archives of Pharmacology vol 369 no 6 pp547ndash553 2004

[27] M E Page M J Detke A Dalvi L G Kirby and I LuckildquoSerotonergic mediation of the effects of fluoxetine but notdesipramine in the rat forced swimming testrdquo Psychopharma-cology vol 147 no 2 pp 162ndash167 1999

[28] M E Page and I Lucki ldquoEffects of acute and chronic reboxetinetreatment on stress-inducedmonoamine efflux in the rat frontalcortexrdquo Neuropsychopharmacology vol 27 no 2 pp 237ndash2472002

[29] F P Bymaster W Zhang P A Carter et al ldquoFluoxetinebut not other selective serotonin uptake inhibitors increasesnorepinephrine and dopamine extracellular levels in prefrontalcortexrdquo Psychopharmacology vol 160 no 4 pp 353ndash361 2002

[30] D T Chau P V Rada K Kim R A Kosloff and B G HoebelldquoFluoxetine alleviates behavioral depression while decreasingacetylcholine release in the nucleus accumbens shellrdquoNeuropsy-chopharmacology vol 36 no 8 pp 1729ndash1737 2011

[31] S J Corne R W Pickering and B T Warner ldquoA methodfor assessing the effects of drugs on the central actions of5-hydroxytryptaminerdquo British Journal of Pharmacology andChemotherapy vol 20 pp 106ndash120 1963

[32] S Schreiber and C G Pick ldquoFluoxetine for blepharospasminteraction of serotonin and dopaminerdquo Journal of Nervous andMental Disease vol 183 no 11 pp 719ndash721 1995

[33] W D Essman A Singh and I Lucki ldquoSerotonergic propertiesof cocaine effects on a 5-HT2 receptor-mediated behavior andon extracellular concentrations of serotonin and dopaminerdquoPharmacology Biochemistry and Behavior vol 49 no 1 pp 107ndash113 1994

[34] L-F Xu W-J Chu X-Y Qing et al ldquoProtopine inhibits sero-tonin transporter and noradrenaline transporter and has theantidepressant-like effect in mice modelsrdquoNeuropharmacologyvol 50 no 8 pp 934ndash940 2006

[35] GWDeMuth and SHAckerman ldquo120572-Methyldopa and depres-sion a clinical study and review of the literaturerdquo AmericanJournal of Psychiatry vol 140 no 5 pp 534ndash538 1983

[36] J Ji J L Mcdermott and D E Dluzen ldquoSex differences inK+-evoked striatal dopamine output from superfused striataltissue fragments of reserpine-treated CD-1 micerdquo Journal ofNeuroendocrinology vol 19 no 9 pp 725ndash731 2007

[37] R R Metzger J M Brown V Sandoval et al ldquoInhibitoryeffect of reserpine ondopamine transporter functionrdquoEuropeanJournal of Pharmacology vol 456 no 1ndash3 pp 39ndash43 2002

[38] M Fukui R M Rodriguiz J Zhou et al ldquoVmat2 heterozygousmutant mice display a depressive-like phenotyperdquo Journal ofNeuroscience vol 27 no 39 pp 10520ndash10529 2007

[39] E Woode E Boakye-Gyasi N Amidu C Ansah and MDuwiejua ldquoAnxiolytic and antidepressant effects of a leafextract ofPalisota hirsutaK Schum (Commelinaceae) inmicerdquoInternational Journal of Pharmacology vol 6 no 1 pp 1ndash172010

[40] E Poleszak P Wlaz B Szewczyk et al ldquoA complexinteraction between glycineNMDA receptors andserotonergicnoradrenergic antidepressants in the forcedswim test in micerdquo Journal of Neural Transmission vol 118 no11 pp 1535ndash1546 2011

[41] E Berrocoso K Ikeda I Sora et al ldquoActive behavioursproduced by antidepressants and opioids in the mouse tailsuspension testrdquoThe International Journal of Neuropsychophar-macology vol 61 no 1 pp 151ndash162 2012

[42] J F Cryan and I Lucki ldquoAntidepressant-like behavioral effectsmediated by 5-hydroxytryptamine(2C) receptorsrdquo Journal ofPharmacology andExperimentalTherapeutics vol 295 no 3 pp1120ndash1126 2000

Submit your manuscripts athttpwwwhindawicom

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Pharmaceutics

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MEDIATORSINFLAMMATION

of

ISRN Pharmacology 3

water was changed to 20 cm For tail suspension immobilityperiod was scored whilst for the modified swimming testmean immobility counts mean swimming counts and meanclimbing counts were scored

27 Involvement of GlycineNMDA Neurotransmission Micewere divided into 2 groups A and B Groups A and B werefurther subdivided into 6 groups each (119899 = 8) Brieflyfive groups of mice from group A received d-cycloserine(25mg kgminus1 ip) and 30min after the first three groupsreceived an oral dose of the extract (10ndash100mg kgminus1) withthe last two groups receiving either fluoxetine (10mg kgminus1)or desipramine (10mg kgminus1 ip) The sixth group receivedonly d-cycloserine Again five groups of mice from groupB received d-serine (600mg kgminus1) and 30min after thefirst three groups received an oral dose of the extract (10ndash100mg kgminus1) with the last two groups receiving either flu-oxetine (10mg kgminus1 po) or desipramine (10mg kgminus1 ip)The sixth group from group B received only d-serine Theforced swim and tail suspension tests were used as describedabove to investigate the antidepressant mechanism Pedallingbehaviour was defined as the continuous movement of thepaw of the mice without moving the body while curling wasdefined as the raising of the head of the mouse towards itshind paws

28 Statistics GraphPad Prism for Windows version 403(GraphPad Software San Diego CA USA) was used forall data and statistical analyses 119875 lt 005 was consideredstatistically significant In all the tests a sample size of tenanimals (119899 = 10) were used The time-course curves weresubjected to two-way (treatment times time) repeated measuresanalysis of variance (ANOVA) with Bonferronirsquos post hoc testTotal immobility time distance travelled and time takento find the hidden platform and change in weight for eachtreatment were calculated in arbitrary unit as the area underthe curve (AUC) Differences in AUCs were analysed byANOVA followed by Newman Keulsrsquo post hoc test

3 Results

31 Forced Swimming and Tail Suspension Tests MOE (10ndash100mg kgminus1 po) administered 60min before the test periodsignificantly decreased the frequency of immobility (119865

319

=

2147 119875 lt 0001) (Figure 1(a)) and immobility periods ofmice (119865

319

= 1434 119875 lt 0001) (Figure 1(d)) in a dosedependent manner in the FST In the TST both frequency(119865654

= 0486 119875 = 08159) (Figures 2(a) 2(b) and 2(c))and duration (119865

652

= 2557 119875 lt 0001) (Figures 2(d)2(e) and 2(f)) of immobility decreased indicating significantantidepressant activity

32 Involvement of Noradrenergic Mechanisms Pretreat-ment with reserpine (1mg kgminus1 sc) alone 120572-methyldopa(400mg kgminus1 po) alone or a concomitant administration ofreserpine (1mg kgminus1 sc) and 120572-methyldopa (200mg kgminus1po) did not reverse the decline in immobility caused by

the extract MOE (10ndash100mg kgminus1 po) in the forced swimtest (FST) (Figures 3(a) 3(d) and 3(g)) Results obtainedfor fluoxetine-treated groups (FLX) (3ndash30mg kgminus1 po) weresimilar to that of the extract-treated groups (Figures 3(b)3(e) and 3(h)) In contrast the antidepressant effect ofimipramine (IMI) was reversed by either reserpine alone120572-methyldopa alone or a concomitant administration ofreserpine and 120572-methyldopa (Figures 3(c) 3(f) and 3(i))

33 Involvement of Serotoninergic Mechanism Pretreatmentof mice with pCPA (200mg kgminus1) abolished the antidepres-sant effect ofMOE (10ndash100mg kgminus1 po) and fluoxetine FLX(3ndash30mg kgminus1 po) but not imipramine IMI (3ndash30mg kgminus1po) in the FST The mean counts for immobility (119865

732

=

1463 119875 lt 00001) (Figure 4(a)) swimming (119865732

= 4474119875 lt 00001) (Figure 4(d)) and climbing (119865

732

= 1121 119875 =03742) (Figure 4(g)) in the extract-treated group after pCPApretreatment did not show any difference when comparedwith the control Similar results as above were observed forFLX-treated groups but not imipramine (Figures 4(b)-4(c)4(e)-4(f) and 4(h)-4(i))

In an attempt to investigate the possible involvementof 5-HT

2A receptor activation in the antidepressant actionof the extract mice were given 5-hydroxytryptophan afterextract pretreatment to induced head twitch responses Itwas observed from the time course curve that the extractas well as fluoxetine increased the head twitch responsessignificantly for the period of 30 minutes (Figures 5(a) and5(c)) Response peaked after 15 minutes One-way ANOVAfollowed by Newman Keulsrsquo test of the areas under the curve(AUCs) showed a dose dependent increase in the head twitchresponse for both extract and fluoxetine (Figures 5(b) and5(d))

34 Involvement of GlycineNMDA Receptor Complex In theTST MOE (100mg kgminus1 po) fluoxetine FLX (10mg kgminus1po) and desipramine DSP (10mg kgminus1 ip) exhibited sig-nificant antidepressant effect by decreasing mean immobilityscore which was reversed by d-serine DS (600mg kgminus1 ip)pretreatment (Figure 6(a)) Pretreatment with d-cycloserineDCS (25mg kgminus1 ip) potentiated the effect of MOE andFLX (but not DSP) by further decreasing mean immobilityscore (Figure 6(b)) MOE alone did not affect curling scoreand this was not changed by DS pretreatment (Figure 6(e))FLX and DSP alone caused slight increase in the curlingscore which was reversed by DS Pretreatment with DCSsignificantly increased curling score of MOE but caused onlya modest increase in both FLX and DSP treated groups(Figure 6(f)) MOE DS DCS FLX and DSP alone increasedswinging score DS pretreatment partially inhibited swingingbehaviour byMOE but totally in FLX andDSP treated groups(Figure 6(c)) DCS pretreatment also inhibited swingingbehaviour by MOE and DSP but not FLX (Figure 6(d))

In the forced swim test MOE FLX and DSP decreasedimmobility score and this was reversed by DS pretreatment(Figure 7(a)) Pretreatment with DCS potentiated the effectof MOE and FLX (but not DSP) by further decreasing

4 ISRN Pharmacology

Freq

uenc

y14

12

10

8

6

4

2

0

Ctrl 10 30 100

lowastlowastlowastlowast lowastlowastlowast

lowastlowastlowast

MOE (mg kgminus1)

(a)

3 10 30

lowastlowastlowast

lowastlowastlowastlowastlowastlowast lowastlowastlowastlowastlowastlowast

lowastlowastlowast

FLX (mg kgminus1)

(b)

3 10 30

lowastlowast

lowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

daggerdaggerdagger

daggerdaggerdagger

daggerdaggerdagger

IMI (mg kgminus1)

(c)

MobilityImmobility

Dur

atio

n (s

)

350

300

250

200

150

100

50

0

daggerdaggerdaggerdaggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

Ctrl 10 30 100

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

MOE (mg kgminus1)

(d)

daggerdaggerdagger daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowastlowastlowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

lowastlowastlowast

3 10 30

MobilityImmobility

FLX (mg kgminus1)

(e)

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

3 10 30

MobilityImmobility

IMI (mg kgminus1)

(f)

Figure 1 Effects of extract MOE (10ndash100mg kgminus1) fluoxetine FLX (3ndash30mg kgminus1) and imipramine IMI (3ndash30mg kgminus1) treatment on (ab and c) the frequency of mobility and immobility and (d e and f) duration of mobility and immobility in the FST Data are presented asgroup means plusmn SEM significantly different from control lowastlowastlowast119875 lt 0001 lowastlowast119875 lt 001 (one-way ANOVA followed by Newman Keulsrsquo test)daggerdaggerdagger

119875 lt 0001 comparison between effect and dose (two-way ANOVA followed by Bonferronirsquos test)

immobility score (Figure 7(b)) MOE and FLX unlike DSPincreased swimming behaviour which was inhibited by DSbut increased by DCS pretreatment (Figures 7(c) and 7(d))Climbing scores were decreased by both MOE and FLX andthis was not affected by both DS and DCS pretreatment(Figures 7(e) and 7(f)) DSP on the contrary increasedclimbing score which was unaffected by DCS pretreatmentbut decreased by DS

4 Discussion

Results of the study demonstrated that MOE has significantantidepressant effect in both the forced swimming and thetail suspension tests In both animal models percentageimmobility and frequency of immobility were decreased byextract treatment Reduction in immobility has been used asthe primary index for antidepressant effect of test substancesin these modelsmdashalmost all antidepressants in clinical use

induce a decrease in immobility in rodents whilst other drugsfail to give the same response [22 23]

Preclinical and clinical studies suggest that depletionof a monoamine implicated in depression pathophysiologymay abolish the antidepressant effect of a substance if thesubstance depends on that particular monoamine for itsantidepressant effect [20 24]Hencewhen 5-HTwas depletedby pretreating mice for 3 days with the tryptophan hydrox-ylase inhibitor para-chlorophenylalanine (pCPA) the effectsof drugs that act by enhancing 5-HT neurotransmission wereabolished [25 26] while those that act on noradrenergicpathways were not affected [26ndash28] The inhibition of theantidepressant effect of MOE by pCPA in both TST andFST suggests that its antidepressant effect is dependenton enhancement of serotoninergic neurotransmission Thelack of antidepressant effect of fluoxetine in pCPA-treatedmice is consistent with the hypothesis that fluoxetine elicitsits acute behavioural effects by increasing extracellular 5-HT after blockade of the serotonin transporter [29] The

ISRN Pharmacology 5

Freq

uenc

y10

8

6

4

2

0

Ctrl 10 30 100

lowast

MOE (mg kgminus1)

(a)

10 303

lowast

lowast

FLX (mg kgminus1)

(b)

10 303

lowast

lowastlowast

IMI (mg kgminus1)

(c)

Dur

atio

n (s

)

350

300

250

200

150

100

50

0

MobilityImmobility

Ctrl 10 30 100

daggerdagger daggerdagger

daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast lowastlowastlowast lowastlowastlowast

lowastlowastlowast lowastlowastlowast

lowastlowastlowast

MOE (mg kgminus1)

(d)

MobilityImmobility

10 303

daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

FLX (mg kgminus1)

(e)

MobilityImmobility

10 303

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

IMI (mg kgminus1)

(f)

Figure 2 Effect of the extract MOE (10 30 and 100mg kgminus1) fluoxetine FLX (3 10 and 30mg kgminus1) and imipramine IMI (3 10 and30mg kgminus1) treatment on the (a b and c) frequency of mobility and immobility and (d e and f) duration of mobility and immobility in theTST Data are presented as group means plusmn SEM lowastlowastlowast119875 lt 0001 lowastlowast119875 lt 001 compared to vehicle-treated group (one-way ANOVA followedby Newman Keulsrsquo test) daggerdaggerdagger119875 lt 0001 comparison effect and dose (two-way ANOVA followed by Bonferronirsquos test)

extract and fluoxetine increased swimming score which wasreversed with pCPA pretreatment further supporting theiraction on the serotoninergic system [27 30] Both MOE andfluoxetine did not affect mean climbing score suggesting thattheir behavioural effect may not depend on noradrenergicpathways

Further evidence suggesting that the extract enhances 5-HTneurotransmissionwas derived from its ability to increasehead twitch responses induced by 5-HTP The head twitchresponse (HTR) in rodents induced by 5-hydroxytryptophan(5-HTP) a precursor of 5-HT [31] is considered as a specificbehavioural model for the activation of serotoninergic neu-ron specifically 5-HT

2A receptors [32]Thus it can be inferredthat MOE may be acting via direct or indirect activation of5-HT2A receptors Fluoxetine also increased the frequency of

HTRsThis result is consistentwith a number of studieswherefluoxetine elicited similar responses [33 34]

The present experiments also examined the role of nora-drenaline and dopamine in the acute behavioural effects of

the extract in the modified FST by using drugs that interferewith their neurotransmitter synthesis or release Depletionwith 120572-methyldopa an L-aromatic amino acid decarboxylaseinhibitor that inhibits the biosynthesis of catecholamines and5-HT [35] failed to attenuate the behavioural effects of MOEand fluoxetine while that of imipramine was abolished Thissuggests that MOE may not be affected by the biosynthesisof noradrenaline or dopamine Moreover when vesicularpools were depleted by reserpine the decrease in immobilityelicited by MOE or fluoxetine was not affected Here againthe effect of imipramine was attenuated Reserpine is anirreversible inhibitor of the vesicular monoamine transporter2 (VMAT-2) which is located primarily within the CNS andis responsible for transporting monoamines from the cyto-plasm into secretory vesicles [36 37] Treatment with reser-pine therefore leads to depletion of vesicular monoaminestoresmdashboth serotonin and noradrenaline [38] suggestingboth serotonin and noradrenaline might be important inthe antidepressant effects of imipramine The inability of

6 ISRN Pharmacology

Ctrl 10 30 100

lowastlowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowastIm

mob

ility

tim

e (s)

100

80

60

40

20

0

Untreated120572-MD-treated

MOE (mg kgminus1)

(a)

lowast

lowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowastlowastlowastlowast

Untreated

3 10 30

120572-MD-treated

FLX (mg kgminus1)

(b)

lowast

daggerdagger

daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

Untreated

3 10 30

120572-MD-treated

IMI (mg kgminus1)

(c)

lowastlowast

lowastlowast lowastlowastlowastlowastlowast

lowastlowastlowastlowastlowastlowast

UntreatedReserpinised

Ctrl 10 30 100

Imm

obili

ty ti

me (

s)

100

80

60

40

20

0

MOE (mg kgminus1)

(d)

lowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowast

3 10 30

UntreatedReserpinised

FLX (mg kgminus1)

(e)

lowast

daggerdaggerdagger

daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

3 10 30

UntreatedReserpinised

IMI (mg kgminus1)

(f)

daggerdagger

lowastlowastlowastlowastlowast

lowastlowastlowastlowastlowastlowastlowastlowastlowastlowastlowastlowast

Untreated

120

Imm

obili

ty ti

me (

s)

100

80

60

40

20

0

Ctrl 10 30 100

120572-MDres-treated

MOE (mg kgminus1)

(g)

lowast

lowastlowastlowast

lowastlowastlowast lowastlowastlowast

lowastlowastlowastlowastlowastlowast

3 10 30

Untreated120572-MDres-treated

FLX (mg kgminus1)

(h)

lowastlowast

daggerdaggerdaggerdaggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

3 10 30

Untreated120572-MDres-treated

IMI (mg kgminus1)

(i)

Figure 3 Effects of (andashc) reserpine alone (dndashf) 120572-methyldopa 120572-MD alone or (gndashi) both reserpine and 120572-methyldopa on duration ofimmobility of MOE (10ndash100mg kgminus1 po) fluoxetine (3ndash30mg kgminus1 po) and imipramine (3ndash30mg kgminus1 po) treatment in the FST Dataare presented as mean plusmn SEM of 5 animals significantly different from control lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 by one-way ANOVA followed byNewman Keulsrsquo test dagger119875 lt 005 daggerdagger119875 lt 001 and daggerdaggerdagger119875 lt 0001 significant difference between treatment and dose (two-way ANOVA withBonferroni post hoc test)

ISRN Pharmacology 7

Ctrl 10 30 100

Imm

obili

ty ti

me (

s)

60

40

50

20

10

30

0

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

MOE (mg kgminus1)

(a)

3 10 30

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

FLX (mg kgminus1)

(b)

3 10 30

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowast lowastlowastlowast

lowastlowastlowast

dagger

IMI (mg kgminus1)

(c)

Swim

min

g tim

e (s)

40

50

20

10

30

0

Ctrl 10 30 100

daggerdaggerdagger daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast lowastlowastlowast

lowastlowastlowast

MOE (mg kgminus1)

(d)

3 10 30

daggerdaggerdagger

daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

lowastlowast

FLX (mg kgminus1)

(e)

3 10 30

lowast

IMI (mg kgminus1)

(f)

Clim

bing

tim

e (s)

40

50

20

10

30

0

Ctrl 10 30 100

UntreatedPCPA-treated

MOE (mg kgminus1)

(g)

3 10 30

dagger

dagger

lowastlowastlowast

UntreatedPCPA-treated

FLX (mg kgminus1)

(h)

3 10 30

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

UntreatedPCPA-treated

IMI (mg kgminus1)

(i)

Figure 4 Effects of pCPA (200mg kgminus1) pretreatment on the (andashc) mean immobility counts (dndashf) swimming counts and (gndashi) climbingcounts of oral doses of extract MOE (10ndash100mg kgminus1) fluoxetine FLX (3ndash30mg kgminus1) and IMI (3ndash30mg kgminus1) treated groups in the FSTData are presented as mean plusmn SEM significantly different from control lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 by Newman Keulsrsquo test daggerdaggerdagger119875 lt 0001(two-way ANOVA followed by Bonferronirsquos post test comparison between drug treatment and dose)

8 ISRN Pharmacology

0

0

5

5

10

10

15

15

20

20

25

25

30

30

Time (min)

Ctrl

Ctrl

10 30 100

160

120

80

40

0

35lowastlowast

lowastlowastlowast

lowastlowastlowast

Num

ber o

f hea

d tw

itche

s

AUC

MOEMOEMOE10mg kgminus1

30mg kgminus1100mg kgminus1

(a)

0 5 10 15 20 25 30

Time (min)Ctrl

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

0

5

10

15

20

25

30

35

Num

ber o

f hea

d tw

itche

sFLX

FLXFLX

Ctrl 3 10 30

160

120

80

40

0

AUC

3mg kgminus110mg kgminus130mg kgminus1

(b)

Figure 5 Effect of MOE (10ndash100mg kgminus1 po) and fluoxetine (3ndash30mg kgminus1 po) on the time course curve of head twitch response test andtheir corresponding AUCs (a and b) in the same test represented as bar graphs Data was presented as mean plusmn SEM (119899 = 6) lowastlowastlowast119875 lt 0001lowastlowast

119875 lt 001 compared to vehicle-treated group (one-way ANOVA followed by Newman Keulsrsquo test)

reserpine pretreatment to reverse the antidepressant effectsof the extract and fluoxetine however seems to suggest thatreserpine does not affect vesicular storage of 5-HT to thesame extent as that of noradrenaline In fact this assertionis consistent with the results obtained by OrsquoLeary et aland Woode et al [20 39]mdashthe former demonstrating thatreserpine at the dose used produced a 93 and 95 depletionof cortical noradrenaline and dopamine content respectivelyand a 78 depletion of 5-HT To inhibit synthesis as wellas deplete vesicular pools of noradrenaline and dopaminemice were pretreated with both reserpine and 120572-methyldopaResults were similar to effects observed when mice weretreated with reserpine alone The work published by OrsquoLearyet al [20] indicated that when reserpine was combined with120572-methyl para-tyrosine AMPT (NE and DA biosyntheticinhibitor) a depletion of cortical DA (95) NE (97) and 5-HT (78) was observedThe combination had only a modesteffect on NE and DA but failed to affect 5-HT Though 120572-methyldopa was used instead of the AMPT used by OrsquoLearyand colleagues the results from the combined effect ofreserpine and 120572-methyldopa did not differ significantly fromwhen reserpine was used alone Amore recent publication byWoode et al [39] used 120572-methyldopa and similar results wasobserved These results demonstrate that the antidepressanteffect of MOE may not be dependent on noradrenergicneurotransmission

Both clinical and preclinical studies support the antide-pressant activity of antagonists on functional glycineNMDAreceptor complex These compounds are thought to havelower side effect profiles compared to the competitive and

noncompetitive NMDA antagonists The effect of MOE onglutamatergic neurotransmission was assessed by pretreatingmice with d-serine (DS) a full agonist on glycineNMDAreceptors or d-cycloserine (DCS) a partial agonist onthese receptors In both the TST and FST DS reversedthe decline in immobility by MOE and fluoxetine but DCSpretreatment potentiated the decline demonstrating thatMOE may be acting as an antagonist on the glycineNMDAreceptor complex In contrast the decrease in immobilityof desipramine was reversed by DS but DCS had no effecton it This suggests that the antidepressant effect of bothserotonin and noradrenaline-based compounds depends onthe inhibition of the glycineNMDA receptor complex butthe enhancement of antidepressant activity depends on theserotoninergic pathway and not the noradrenaline pathway[40] This explains why the antidepressant effect of theextract fluoxetine and desipramine was abolished by d-serine but only the effect of the extract and fluoxetine(which act via serotoninergic pathway) was potentiated by d-cycloserine Moreover MOE increased curling score in theTST slightly (suggestive of opioidergic activity) though notsignificant Pretreatment with DCS significantly increasedcurling score of MOE but did not affect both FLX and DSPtreated groups DS pretreatment partially inhibited pedalingbehaviour byMOEbut totally in FLX andDSP treated groupsDCS pretreatment also inhibited pedaling behaviour byMOEand DSP but not FLX According to Berrocoso et al [41]opioids decrease immobility score while increasing curlingbehaviour in mice This suggests that the extract on its ownmay have little effect on opioidergic activity but may interact

ISRN Pharmacology 9

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

daggerdaggerdagger

daggerdaggerdagger

daggerdaggerdagger

Ctrl MOE FLX DSP

50

40

30

20

10

0

Imm

obili

ty ti

me (

s)

(a)

Ctrl MOE FLX DSP

50

40

30

20

10

0

Imm

obili

ty ti

me (

s)

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

daggerdaggerdagger

daggerdaggerdagger

(b)

lowast

lowastlowast

lowastlowastlowast

dagger

daggerdagger

30

25

20

15

10

5

0

Peda

lling

tim

e (s)

Ctrl MOE FLX DSP

(c)

lowast

lowast

lowast

daggerdaggerdagger

30

25

20

15

10

5

0

Peda

lling

tim

e (s)

Ctrl MOE FLX DSP

(d)

Ctrl MOE FLX DSP

UntreatedD-serine-treated

60

Curli

ng ti

me (

s)

50

40

30

20

10

0

lowastlowastlowast

daggerdagger

(e)

daggerdagger

Ctrl MOE FLX DSP

Untreated

60

Curli

ng ti

me (

s)

50

40

30

20

10

0

lowastlowastlowast

lowastlowast

D-cycloserine-treated

(f)

Figure 6 Effects of d-serine (DS) or d-cycloserine (DCS) pretreatment on (a b) mean immobility count (c d) pedalling count and (e f)curling count of extractMOE (100mg kgminus1) fluoxetine FLX (10mg kgminus1) anddesipramineDSP (10mg kgminus1) treatment in the tail suspensiontest (TST) Data are presented as Means plusmn SEM significantly different from control lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 by Newman Keulrsquos testSignificant difference between treatments dagger119875 lt 005 daggerdagger119875 lt 001 and daggerdaggerdagger119875 lt 0001

10 ISRN Pharmacology

Imm

obili

ty ti

me (

s)

60

50

40

30

20

10

0

Ctrl MOE FLX DSP

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

(a)

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

Imm

obili

ty ti

me (

s)

60

50

40

30

20

10

0

Ctrl MOE FLX DSP

daggerdagger

(b)

Swim

min

g tim

e (s)

80

60

40

20

0

Ctrl MOE FLX DSP

lowastlowastlowast lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

daggerdaggerdagger

(c)

Swim

min

g tim

e (s)

80

60

40

20

0

Ctrl MOE FLX DSP

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

daggerdaggerdagger

daggerdagger

lowastlowast

(d)

Clim

bing

tim

e (s)

50

40

30

20

10

8

6

4

2

0

lowastlowast

UntreatedD-serine-treated

lowast

lowast

Ctrl MOE FLX DSP

(e)

Clim

bing

tim

e (s)

50

40

30

20

10

8

6

4

2

0

lowastlowastlowastlowastlowastlowast

UntreatedD-cycloserine-treated

lowast

lowast

dagger

Ctrl MOE FLX DSP

(f)

Figure 7 Effects of d-serine (DS) or d-cycloserine (DCS) pretreatment on (a b) mean immobility count (c d) swimming count and (ef) climbing count of extract MOE (100mg kgminus1) fluoxetine FLX (10mg kgminus1) and desipramine DSP (10mg kgminus1) treatment in the forcedswimming test (FST) Data are presented as means plusmn SEM significantly different from control lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 by Newman Keulrsquostest Significant difference between treatments dagger119875 lt 005 daggerdagger119875 lt 001 and daggerdaggerdagger119875 lt 0001

ISRN Pharmacology 11

with opioid receptors when combined with DCS In the FSTMOE and FLX unlike DSP increased swimming behaviourwhich is sensitive to selective serotonin reuptake inhibitors(SSRIs) and 5HT agonists [22 42] This behavior exhibitedbyMOE and fluoxetine-treated mice was inhibited by DS butincreased byDCS pretreatment further supporting the theorythat antidepressant effect of serotonin based drugs dependson the inhibition of the glycineNMDA receptor complexand the enhancement of antidepressant activity dependson the serotoninergic pathway [40] Climbing scores weredecreased by both MOE and FLX and this was not affectedby both DS and DCS pretreatment This confirms theirlack of noradrenergic activity DSP a selective noradrenergicreuptake inhibitor on the contrary increased climbing scorewhich was unaffected by DCS pretreatment but decreasedby DS It is worth mentioning that the extract fluoxetinedesipramine alone or their combination with either d-serineor d-cycloserine did not impair motor coordination Thusthe behavioural effect observed can be attributed to drugtreatment alone

5 Conclusion

The present study shows that Mallotus oppositifolius hasantidepressant-like effect in mice and this may be mediatedvia enhancement of serotoninergic neurotransmission andinhibition of glycineNMDA receptor complex activationThe antidepressant effect of the extract may be devoid ofnoradrenergic mechanisms

Conflict of Interests

The authors declare that they have no conflict of interests

References

[1] P V Holmes ldquoRodent models of depression reexaminingvalidity without anthropomorphic inferencerdquo Critical Reviewsin Neurobiology vol 15 no 2 pp 143ndash174 2003

[2] J Alonso M C Angermeyer S Bernert et al ldquoPrevalence ofmental disorders in Europe results from the European Study ofthe Epidemiology ofMental Disorders (ESEMeD) projectrdquoActaPsychiatrica Scandinavica Supplement vol 109 no 420 pp 21ndash27 2004

[3] T B Ustun J L Ayuso-Mateos S Chatterji C Mathers and CJ L Murray ldquoGlobal burden of depressive disorders in the year2000rdquo British Journal of Psychiatry vol 184 pp 386ndash392 2004

[4] H Gilmour and S B Patten ldquoDepression and work impair-mentrdquo Health Reports vol 18 no 1 pp 9ndash22 2007

[5] E Poleszak B Szewczyk E Kedzierska P Wlaz A Pilcand G Nowak ldquoAntidepressant- and anxiolytic-like activity ofmagnesium in micerdquo Pharmacology Biochemistry and Behaviorvol 78 no 1 pp 7ndash12 2004

[6] P Skolnick P Popik and R Trullas ldquoGlutamate-based antide-pressants 20 years onrdquo Trends in Pharmacological Sciences vol30 no 11 pp 563ndash569 2009

[7] J F Cryan A Markou and I Lucki ldquoAssessing antidepressantactivity in rodents recent developments and future needsrdquoTrends in Pharmacological Sciences vol 23 no 5 pp 238ndash2452002

[8] E J Nestler M Barrot R J DiLeone A J Eisch S J Gold andLMMonteggia ldquoNeurobiology of depressionrdquoNeuron vol 34no 1 pp 13ndash25 2002

[9] R Trullas and P Skolnick ldquoFunctional antagonists at theNMDA receptor complex exhibit antidepressant actionsrdquo Euro-pean Journal of Pharmacology vol 185 no 1 pp 1ndash10 1990

[10] M Siwek D Dudek I A Paul et al ldquoZinc supplementationaugments efficacy of imipramine in treatment resistant patientsa double blind placebo-controlled studyrdquo Journal of AffectiveDisorders vol 118 no 1ndash3 pp 187ndash195 2009

[11] R M Berman A Cappiello A Anand et al ldquoAntidepressanteffects of ketamine in depressed patientsrdquo Biological Psychiatryvol 47 no 4 pp 351ndash354 2000

[12] C A Zarate Jr N E Brutsche L Ibrahim et al ldquoReplicationof Ketaminersquos antidepressant efficacy in bipolar depression arandomized controlled add-on trialrdquo Biological Psychiatry vol71 no 11 pp 939ndash946 2012

[13] W-L Zhu S-J Wang M-M Liu et al ldquoGlycine siteN-methyl-D-aspartate receptor antagonist7-CTKA producesrapid antidepressant-like effects in male ratsrdquo Journal of Psychi-atry amp Neuroscience vol 38 no 5 pp 306ndash316 2013

[14] S Akhondzadeh and S H Abbasi ldquoHerbal medicine inthe treatment of Alzhelmerrsquos diseaserdquo American Journal ofAlzheimerrsquos Disease and other Dementias vol 21 no 2 pp 113ndash118 2006

[15] D P Briskin ldquoMedicinal plants and phytomedicines Linkingplant biochemistry and physiology to human healthrdquo PlantPhysiology vol 124 no 2 pp 507ndash514 2000

[16] R M Darwish and T A Aburjai ldquoEffect of ethnomedicinalplants used in folklore medicine in Jordan as antibiotic resis-tant inhibitors on Escherichia colirdquo BMC Complementary andAlternative Medicine vol 10 article 9 2010

[17] NRC Guideforthe Careand Useof Laboratory Animals TheNational Academies Press 1996

[18] R D Porsolt M Le Pichon and M Jalfre ldquoDepression a newanimal model sensitive to antidepressant treatmentsrdquo Naturevol 266 no 5604 pp 730ndash732 1977

[19] L Steru R Chermat B Thierry and P Simon ldquoThe tailsuspension test a new method for screening antidepressants inmicerdquo Psychopharmacology vol 85 no 3 pp 367ndash370 1985

[20] O F OrsquoLeary A J Bechtholt J J Crowley T E Hill M EPage and I Lucki ldquoDepletion of serotonin and catecholaminesblock the acute behavioral response to different classes ofantidepressant drugs in the mouse tail suspension testrdquo Psy-chopharmacology vol 192 no 3 pp 357ndash371 2007

[21] P L M van Giersbergen E van Duinkerken C G J SweepV M Wiegant J M van Ree and W de Jong ldquo120572-Methyldopainduces a naltrexone-insensitive antinociception and hypo-motility in ratsrdquo British Journal of Pharmacology vol 99 no 3pp 467ndash472 1990

[22] J F Cryan M E Page and I Lucki ldquoDifferential behav-ioral effects of the antidepressants reboxetine fluoxetine andmoclobemide in a modified forced swim test following chronictreatmentrdquo Psychopharmacology vol 182 no 3 pp 335ndash3442005

[23] B Petit-Demouliere F Chenu and M Bourin ldquoForced swim-ming test in mice a review of antidepressant activityrdquo Psy-chopharmacology vol 177 no 3 pp 245ndash255 2005

[24] P L Delgado H L Miller R M Salomon et al ldquoTryptophan-depletion challenge in depressed patients treated withdesipramine or fluoxetine implications for the role of

12 ISRN Pharmacology

serotonin in the mechanism of antidepressant actionrdquoBiological Psychiatry vol 46 no 2 pp 212ndash220 1999

[25] A L Eckeli F Dach and A L S Rodrigues ldquoAcute treatmentswith GMP produce antidepressant-like effects in micerdquo Neu-roReport vol 11 no 9 pp 1839ndash1843 2000

[26] E C Gavioli CW Vaughan GMarzola et al ldquoAntidepressant-like effects of the nociceptinorphanin FQ receptor antago-nist UFP-101 new evidence from rats and micerdquo Naunyn-Schmiedebergrsquos Archives of Pharmacology vol 369 no 6 pp547ndash553 2004

[27] M E Page M J Detke A Dalvi L G Kirby and I LuckildquoSerotonergic mediation of the effects of fluoxetine but notdesipramine in the rat forced swimming testrdquo Psychopharma-cology vol 147 no 2 pp 162ndash167 1999

[28] M E Page and I Lucki ldquoEffects of acute and chronic reboxetinetreatment on stress-inducedmonoamine efflux in the rat frontalcortexrdquo Neuropsychopharmacology vol 27 no 2 pp 237ndash2472002

[29] F P Bymaster W Zhang P A Carter et al ldquoFluoxetinebut not other selective serotonin uptake inhibitors increasesnorepinephrine and dopamine extracellular levels in prefrontalcortexrdquo Psychopharmacology vol 160 no 4 pp 353ndash361 2002

[30] D T Chau P V Rada K Kim R A Kosloff and B G HoebelldquoFluoxetine alleviates behavioral depression while decreasingacetylcholine release in the nucleus accumbens shellrdquoNeuropsy-chopharmacology vol 36 no 8 pp 1729ndash1737 2011

[31] S J Corne R W Pickering and B T Warner ldquoA methodfor assessing the effects of drugs on the central actions of5-hydroxytryptaminerdquo British Journal of Pharmacology andChemotherapy vol 20 pp 106ndash120 1963

[32] S Schreiber and C G Pick ldquoFluoxetine for blepharospasminteraction of serotonin and dopaminerdquo Journal of Nervous andMental Disease vol 183 no 11 pp 719ndash721 1995

[33] W D Essman A Singh and I Lucki ldquoSerotonergic propertiesof cocaine effects on a 5-HT2 receptor-mediated behavior andon extracellular concentrations of serotonin and dopaminerdquoPharmacology Biochemistry and Behavior vol 49 no 1 pp 107ndash113 1994

[34] L-F Xu W-J Chu X-Y Qing et al ldquoProtopine inhibits sero-tonin transporter and noradrenaline transporter and has theantidepressant-like effect in mice modelsrdquoNeuropharmacologyvol 50 no 8 pp 934ndash940 2006

[35] GWDeMuth and SHAckerman ldquo120572-Methyldopa and depres-sion a clinical study and review of the literaturerdquo AmericanJournal of Psychiatry vol 140 no 5 pp 534ndash538 1983

[36] J Ji J L Mcdermott and D E Dluzen ldquoSex differences inK+-evoked striatal dopamine output from superfused striataltissue fragments of reserpine-treated CD-1 micerdquo Journal ofNeuroendocrinology vol 19 no 9 pp 725ndash731 2007

[37] R R Metzger J M Brown V Sandoval et al ldquoInhibitoryeffect of reserpine ondopamine transporter functionrdquoEuropeanJournal of Pharmacology vol 456 no 1ndash3 pp 39ndash43 2002

[38] M Fukui R M Rodriguiz J Zhou et al ldquoVmat2 heterozygousmutant mice display a depressive-like phenotyperdquo Journal ofNeuroscience vol 27 no 39 pp 10520ndash10529 2007

[39] E Woode E Boakye-Gyasi N Amidu C Ansah and MDuwiejua ldquoAnxiolytic and antidepressant effects of a leafextract ofPalisota hirsutaK Schum (Commelinaceae) inmicerdquoInternational Journal of Pharmacology vol 6 no 1 pp 1ndash172010

[40] E Poleszak P Wlaz B Szewczyk et al ldquoA complexinteraction between glycineNMDA receptors andserotonergicnoradrenergic antidepressants in the forcedswim test in micerdquo Journal of Neural Transmission vol 118 no11 pp 1535ndash1546 2011

[41] E Berrocoso K Ikeda I Sora et al ldquoActive behavioursproduced by antidepressants and opioids in the mouse tailsuspension testrdquoThe International Journal of Neuropsychophar-macology vol 61 no 1 pp 151ndash162 2012

[42] J F Cryan and I Lucki ldquoAntidepressant-like behavioral effectsmediated by 5-hydroxytryptamine(2C) receptorsrdquo Journal ofPharmacology andExperimentalTherapeutics vol 295 no 3 pp1120ndash1126 2000

Submit your manuscripts athttpwwwhindawicom

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ToxinsJournal of

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Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

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AntibioticsInternational Journal of

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Drug DeliveryJournal of

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in Pharmacological Sciences

Tropical MedicineJournal of

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Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

AddictionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Autoimmune Diseases

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Anesthesiology Research and Practice

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Journal of

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Pharmaceutics

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MEDIATORSINFLAMMATION

of

4 ISRN Pharmacology

Freq

uenc

y14

12

10

8

6

4

2

0

Ctrl 10 30 100

lowastlowastlowastlowast lowastlowastlowast

lowastlowastlowast

MOE (mg kgminus1)

(a)

3 10 30

lowastlowastlowast

lowastlowastlowastlowastlowastlowast lowastlowastlowastlowastlowastlowast

lowastlowastlowast

FLX (mg kgminus1)

(b)

3 10 30

lowastlowast

lowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

daggerdaggerdagger

daggerdaggerdagger

daggerdaggerdagger

IMI (mg kgminus1)

(c)

MobilityImmobility

Dur

atio

n (s

)

350

300

250

200

150

100

50

0

daggerdaggerdaggerdaggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

Ctrl 10 30 100

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

MOE (mg kgminus1)

(d)

daggerdaggerdagger daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowastlowastlowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

lowastlowastlowast

3 10 30

MobilityImmobility

FLX (mg kgminus1)

(e)

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

3 10 30

MobilityImmobility

IMI (mg kgminus1)

(f)

Figure 1 Effects of extract MOE (10ndash100mg kgminus1) fluoxetine FLX (3ndash30mg kgminus1) and imipramine IMI (3ndash30mg kgminus1) treatment on (ab and c) the frequency of mobility and immobility and (d e and f) duration of mobility and immobility in the FST Data are presented asgroup means plusmn SEM significantly different from control lowastlowastlowast119875 lt 0001 lowastlowast119875 lt 001 (one-way ANOVA followed by Newman Keulsrsquo test)daggerdaggerdagger

119875 lt 0001 comparison between effect and dose (two-way ANOVA followed by Bonferronirsquos test)

immobility score (Figure 7(b)) MOE and FLX unlike DSPincreased swimming behaviour which was inhibited by DSbut increased by DCS pretreatment (Figures 7(c) and 7(d))Climbing scores were decreased by both MOE and FLX andthis was not affected by both DS and DCS pretreatment(Figures 7(e) and 7(f)) DSP on the contrary increasedclimbing score which was unaffected by DCS pretreatmentbut decreased by DS

4 Discussion

Results of the study demonstrated that MOE has significantantidepressant effect in both the forced swimming and thetail suspension tests In both animal models percentageimmobility and frequency of immobility were decreased byextract treatment Reduction in immobility has been used asthe primary index for antidepressant effect of test substancesin these modelsmdashalmost all antidepressants in clinical use

induce a decrease in immobility in rodents whilst other drugsfail to give the same response [22 23]

Preclinical and clinical studies suggest that depletionof a monoamine implicated in depression pathophysiologymay abolish the antidepressant effect of a substance if thesubstance depends on that particular monoamine for itsantidepressant effect [20 24]Hencewhen 5-HTwas depletedby pretreating mice for 3 days with the tryptophan hydrox-ylase inhibitor para-chlorophenylalanine (pCPA) the effectsof drugs that act by enhancing 5-HT neurotransmission wereabolished [25 26] while those that act on noradrenergicpathways were not affected [26ndash28] The inhibition of theantidepressant effect of MOE by pCPA in both TST andFST suggests that its antidepressant effect is dependenton enhancement of serotoninergic neurotransmission Thelack of antidepressant effect of fluoxetine in pCPA-treatedmice is consistent with the hypothesis that fluoxetine elicitsits acute behavioural effects by increasing extracellular 5-HT after blockade of the serotonin transporter [29] The

ISRN Pharmacology 5

Freq

uenc

y10

8

6

4

2

0

Ctrl 10 30 100

lowast

MOE (mg kgminus1)

(a)

10 303

lowast

lowast

FLX (mg kgminus1)

(b)

10 303

lowast

lowastlowast

IMI (mg kgminus1)

(c)

Dur

atio

n (s

)

350

300

250

200

150

100

50

0

MobilityImmobility

Ctrl 10 30 100

daggerdagger daggerdagger

daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast lowastlowastlowast lowastlowastlowast

lowastlowastlowast lowastlowastlowast

lowastlowastlowast

MOE (mg kgminus1)

(d)

MobilityImmobility

10 303

daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

FLX (mg kgminus1)

(e)

MobilityImmobility

10 303

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

IMI (mg kgminus1)

(f)

Figure 2 Effect of the extract MOE (10 30 and 100mg kgminus1) fluoxetine FLX (3 10 and 30mg kgminus1) and imipramine IMI (3 10 and30mg kgminus1) treatment on the (a b and c) frequency of mobility and immobility and (d e and f) duration of mobility and immobility in theTST Data are presented as group means plusmn SEM lowastlowastlowast119875 lt 0001 lowastlowast119875 lt 001 compared to vehicle-treated group (one-way ANOVA followedby Newman Keulsrsquo test) daggerdaggerdagger119875 lt 0001 comparison effect and dose (two-way ANOVA followed by Bonferronirsquos test)

extract and fluoxetine increased swimming score which wasreversed with pCPA pretreatment further supporting theiraction on the serotoninergic system [27 30] Both MOE andfluoxetine did not affect mean climbing score suggesting thattheir behavioural effect may not depend on noradrenergicpathways

Further evidence suggesting that the extract enhances 5-HTneurotransmissionwas derived from its ability to increasehead twitch responses induced by 5-HTP The head twitchresponse (HTR) in rodents induced by 5-hydroxytryptophan(5-HTP) a precursor of 5-HT [31] is considered as a specificbehavioural model for the activation of serotoninergic neu-ron specifically 5-HT

2A receptors [32]Thus it can be inferredthat MOE may be acting via direct or indirect activation of5-HT2A receptors Fluoxetine also increased the frequency of

HTRsThis result is consistentwith a number of studieswherefluoxetine elicited similar responses [33 34]

The present experiments also examined the role of nora-drenaline and dopamine in the acute behavioural effects of

the extract in the modified FST by using drugs that interferewith their neurotransmitter synthesis or release Depletionwith 120572-methyldopa an L-aromatic amino acid decarboxylaseinhibitor that inhibits the biosynthesis of catecholamines and5-HT [35] failed to attenuate the behavioural effects of MOEand fluoxetine while that of imipramine was abolished Thissuggests that MOE may not be affected by the biosynthesisof noradrenaline or dopamine Moreover when vesicularpools were depleted by reserpine the decrease in immobilityelicited by MOE or fluoxetine was not affected Here againthe effect of imipramine was attenuated Reserpine is anirreversible inhibitor of the vesicular monoamine transporter2 (VMAT-2) which is located primarily within the CNS andis responsible for transporting monoamines from the cyto-plasm into secretory vesicles [36 37] Treatment with reser-pine therefore leads to depletion of vesicular monoaminestoresmdashboth serotonin and noradrenaline [38] suggestingboth serotonin and noradrenaline might be important inthe antidepressant effects of imipramine The inability of

6 ISRN Pharmacology

Ctrl 10 30 100

lowastlowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowastIm

mob

ility

tim

e (s)

100

80

60

40

20

0

Untreated120572-MD-treated

MOE (mg kgminus1)

(a)

lowast

lowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowastlowastlowastlowast

Untreated

3 10 30

120572-MD-treated

FLX (mg kgminus1)

(b)

lowast

daggerdagger

daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

Untreated

3 10 30

120572-MD-treated

IMI (mg kgminus1)

(c)

lowastlowast

lowastlowast lowastlowastlowastlowastlowast

lowastlowastlowastlowastlowastlowast

UntreatedReserpinised

Ctrl 10 30 100

Imm

obili

ty ti

me (

s)

100

80

60

40

20

0

MOE (mg kgminus1)

(d)

lowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowast

3 10 30

UntreatedReserpinised

FLX (mg kgminus1)

(e)

lowast

daggerdaggerdagger

daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

3 10 30

UntreatedReserpinised

IMI (mg kgminus1)

(f)

daggerdagger

lowastlowastlowastlowastlowast

lowastlowastlowastlowastlowastlowastlowastlowastlowastlowastlowastlowast

Untreated

120

Imm

obili

ty ti

me (

s)

100

80

60

40

20

0

Ctrl 10 30 100

120572-MDres-treated

MOE (mg kgminus1)

(g)

lowast

lowastlowastlowast

lowastlowastlowast lowastlowastlowast

lowastlowastlowastlowastlowastlowast

3 10 30

Untreated120572-MDres-treated

FLX (mg kgminus1)

(h)

lowastlowast

daggerdaggerdaggerdaggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

3 10 30

Untreated120572-MDres-treated

IMI (mg kgminus1)

(i)

Figure 3 Effects of (andashc) reserpine alone (dndashf) 120572-methyldopa 120572-MD alone or (gndashi) both reserpine and 120572-methyldopa on duration ofimmobility of MOE (10ndash100mg kgminus1 po) fluoxetine (3ndash30mg kgminus1 po) and imipramine (3ndash30mg kgminus1 po) treatment in the FST Dataare presented as mean plusmn SEM of 5 animals significantly different from control lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 by one-way ANOVA followed byNewman Keulsrsquo test dagger119875 lt 005 daggerdagger119875 lt 001 and daggerdaggerdagger119875 lt 0001 significant difference between treatment and dose (two-way ANOVA withBonferroni post hoc test)

ISRN Pharmacology 7

Ctrl 10 30 100

Imm

obili

ty ti

me (

s)

60

40

50

20

10

30

0

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

MOE (mg kgminus1)

(a)

3 10 30

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

FLX (mg kgminus1)

(b)

3 10 30

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowast lowastlowastlowast

lowastlowastlowast

dagger

IMI (mg kgminus1)

(c)

Swim

min

g tim

e (s)

40

50

20

10

30

0

Ctrl 10 30 100

daggerdaggerdagger daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast lowastlowastlowast

lowastlowastlowast

MOE (mg kgminus1)

(d)

3 10 30

daggerdaggerdagger

daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

lowastlowast

FLX (mg kgminus1)

(e)

3 10 30

lowast

IMI (mg kgminus1)

(f)

Clim

bing

tim

e (s)

40

50

20

10

30

0

Ctrl 10 30 100

UntreatedPCPA-treated

MOE (mg kgminus1)

(g)

3 10 30

dagger

dagger

lowastlowastlowast

UntreatedPCPA-treated

FLX (mg kgminus1)

(h)

3 10 30

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

UntreatedPCPA-treated

IMI (mg kgminus1)

(i)

Figure 4 Effects of pCPA (200mg kgminus1) pretreatment on the (andashc) mean immobility counts (dndashf) swimming counts and (gndashi) climbingcounts of oral doses of extract MOE (10ndash100mg kgminus1) fluoxetine FLX (3ndash30mg kgminus1) and IMI (3ndash30mg kgminus1) treated groups in the FSTData are presented as mean plusmn SEM significantly different from control lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 by Newman Keulsrsquo test daggerdaggerdagger119875 lt 0001(two-way ANOVA followed by Bonferronirsquos post test comparison between drug treatment and dose)

8 ISRN Pharmacology

0

0

5

5

10

10

15

15

20

20

25

25

30

30

Time (min)

Ctrl

Ctrl

10 30 100

160

120

80

40

0

35lowastlowast

lowastlowastlowast

lowastlowastlowast

Num

ber o

f hea

d tw

itche

s

AUC

MOEMOEMOE10mg kgminus1

30mg kgminus1100mg kgminus1

(a)

0 5 10 15 20 25 30

Time (min)Ctrl

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

0

5

10

15

20

25

30

35

Num

ber o

f hea

d tw

itche

sFLX

FLXFLX

Ctrl 3 10 30

160

120

80

40

0

AUC

3mg kgminus110mg kgminus130mg kgminus1

(b)

Figure 5 Effect of MOE (10ndash100mg kgminus1 po) and fluoxetine (3ndash30mg kgminus1 po) on the time course curve of head twitch response test andtheir corresponding AUCs (a and b) in the same test represented as bar graphs Data was presented as mean plusmn SEM (119899 = 6) lowastlowastlowast119875 lt 0001lowastlowast

119875 lt 001 compared to vehicle-treated group (one-way ANOVA followed by Newman Keulsrsquo test)

reserpine pretreatment to reverse the antidepressant effectsof the extract and fluoxetine however seems to suggest thatreserpine does not affect vesicular storage of 5-HT to thesame extent as that of noradrenaline In fact this assertionis consistent with the results obtained by OrsquoLeary et aland Woode et al [20 39]mdashthe former demonstrating thatreserpine at the dose used produced a 93 and 95 depletionof cortical noradrenaline and dopamine content respectivelyand a 78 depletion of 5-HT To inhibit synthesis as wellas deplete vesicular pools of noradrenaline and dopaminemice were pretreated with both reserpine and 120572-methyldopaResults were similar to effects observed when mice weretreated with reserpine alone The work published by OrsquoLearyet al [20] indicated that when reserpine was combined with120572-methyl para-tyrosine AMPT (NE and DA biosyntheticinhibitor) a depletion of cortical DA (95) NE (97) and 5-HT (78) was observedThe combination had only a modesteffect on NE and DA but failed to affect 5-HT Though 120572-methyldopa was used instead of the AMPT used by OrsquoLearyand colleagues the results from the combined effect ofreserpine and 120572-methyldopa did not differ significantly fromwhen reserpine was used alone Amore recent publication byWoode et al [39] used 120572-methyldopa and similar results wasobserved These results demonstrate that the antidepressanteffect of MOE may not be dependent on noradrenergicneurotransmission

Both clinical and preclinical studies support the antide-pressant activity of antagonists on functional glycineNMDAreceptor complex These compounds are thought to havelower side effect profiles compared to the competitive and

noncompetitive NMDA antagonists The effect of MOE onglutamatergic neurotransmission was assessed by pretreatingmice with d-serine (DS) a full agonist on glycineNMDAreceptors or d-cycloserine (DCS) a partial agonist onthese receptors In both the TST and FST DS reversedthe decline in immobility by MOE and fluoxetine but DCSpretreatment potentiated the decline demonstrating thatMOE may be acting as an antagonist on the glycineNMDAreceptor complex In contrast the decrease in immobilityof desipramine was reversed by DS but DCS had no effecton it This suggests that the antidepressant effect of bothserotonin and noradrenaline-based compounds depends onthe inhibition of the glycineNMDA receptor complex butthe enhancement of antidepressant activity depends on theserotoninergic pathway and not the noradrenaline pathway[40] This explains why the antidepressant effect of theextract fluoxetine and desipramine was abolished by d-serine but only the effect of the extract and fluoxetine(which act via serotoninergic pathway) was potentiated by d-cycloserine Moreover MOE increased curling score in theTST slightly (suggestive of opioidergic activity) though notsignificant Pretreatment with DCS significantly increasedcurling score of MOE but did not affect both FLX and DSPtreated groups DS pretreatment partially inhibited pedalingbehaviour byMOEbut totally in FLX andDSP treated groupsDCS pretreatment also inhibited pedaling behaviour byMOEand DSP but not FLX According to Berrocoso et al [41]opioids decrease immobility score while increasing curlingbehaviour in mice This suggests that the extract on its ownmay have little effect on opioidergic activity but may interact

ISRN Pharmacology 9

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

daggerdaggerdagger

daggerdaggerdagger

daggerdaggerdagger

Ctrl MOE FLX DSP

50

40

30

20

10

0

Imm

obili

ty ti

me (

s)

(a)

Ctrl MOE FLX DSP

50

40

30

20

10

0

Imm

obili

ty ti

me (

s)

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

daggerdaggerdagger

daggerdaggerdagger

(b)

lowast

lowastlowast

lowastlowastlowast

dagger

daggerdagger

30

25

20

15

10

5

0

Peda

lling

tim

e (s)

Ctrl MOE FLX DSP

(c)

lowast

lowast

lowast

daggerdaggerdagger

30

25

20

15

10

5

0

Peda

lling

tim

e (s)

Ctrl MOE FLX DSP

(d)

Ctrl MOE FLX DSP

UntreatedD-serine-treated

60

Curli

ng ti

me (

s)

50

40

30

20

10

0

lowastlowastlowast

daggerdagger

(e)

daggerdagger

Ctrl MOE FLX DSP

Untreated

60

Curli

ng ti

me (

s)

50

40

30

20

10

0

lowastlowastlowast

lowastlowast

D-cycloserine-treated

(f)

Figure 6 Effects of d-serine (DS) or d-cycloserine (DCS) pretreatment on (a b) mean immobility count (c d) pedalling count and (e f)curling count of extractMOE (100mg kgminus1) fluoxetine FLX (10mg kgminus1) anddesipramineDSP (10mg kgminus1) treatment in the tail suspensiontest (TST) Data are presented as Means plusmn SEM significantly different from control lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 by Newman Keulrsquos testSignificant difference between treatments dagger119875 lt 005 daggerdagger119875 lt 001 and daggerdaggerdagger119875 lt 0001

10 ISRN Pharmacology

Imm

obili

ty ti

me (

s)

60

50

40

30

20

10

0

Ctrl MOE FLX DSP

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

(a)

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

Imm

obili

ty ti

me (

s)

60

50

40

30

20

10

0

Ctrl MOE FLX DSP

daggerdagger

(b)

Swim

min

g tim

e (s)

80

60

40

20

0

Ctrl MOE FLX DSP

lowastlowastlowast lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

daggerdaggerdagger

(c)

Swim

min

g tim

e (s)

80

60

40

20

0

Ctrl MOE FLX DSP

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

daggerdaggerdagger

daggerdagger

lowastlowast

(d)

Clim

bing

tim

e (s)

50

40

30

20

10

8

6

4

2

0

lowastlowast

UntreatedD-serine-treated

lowast

lowast

Ctrl MOE FLX DSP

(e)

Clim

bing

tim

e (s)

50

40

30

20

10

8

6

4

2

0

lowastlowastlowastlowastlowastlowast

UntreatedD-cycloserine-treated

lowast

lowast

dagger

Ctrl MOE FLX DSP

(f)

Figure 7 Effects of d-serine (DS) or d-cycloserine (DCS) pretreatment on (a b) mean immobility count (c d) swimming count and (ef) climbing count of extract MOE (100mg kgminus1) fluoxetine FLX (10mg kgminus1) and desipramine DSP (10mg kgminus1) treatment in the forcedswimming test (FST) Data are presented as means plusmn SEM significantly different from control lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 by Newman Keulrsquostest Significant difference between treatments dagger119875 lt 005 daggerdagger119875 lt 001 and daggerdaggerdagger119875 lt 0001

ISRN Pharmacology 11

with opioid receptors when combined with DCS In the FSTMOE and FLX unlike DSP increased swimming behaviourwhich is sensitive to selective serotonin reuptake inhibitors(SSRIs) and 5HT agonists [22 42] This behavior exhibitedbyMOE and fluoxetine-treated mice was inhibited by DS butincreased byDCS pretreatment further supporting the theorythat antidepressant effect of serotonin based drugs dependson the inhibition of the glycineNMDA receptor complexand the enhancement of antidepressant activity dependson the serotoninergic pathway [40] Climbing scores weredecreased by both MOE and FLX and this was not affectedby both DS and DCS pretreatment This confirms theirlack of noradrenergic activity DSP a selective noradrenergicreuptake inhibitor on the contrary increased climbing scorewhich was unaffected by DCS pretreatment but decreasedby DS It is worth mentioning that the extract fluoxetinedesipramine alone or their combination with either d-serineor d-cycloserine did not impair motor coordination Thusthe behavioural effect observed can be attributed to drugtreatment alone

5 Conclusion

The present study shows that Mallotus oppositifolius hasantidepressant-like effect in mice and this may be mediatedvia enhancement of serotoninergic neurotransmission andinhibition of glycineNMDA receptor complex activationThe antidepressant effect of the extract may be devoid ofnoradrenergic mechanisms

Conflict of Interests

The authors declare that they have no conflict of interests

References

[1] P V Holmes ldquoRodent models of depression reexaminingvalidity without anthropomorphic inferencerdquo Critical Reviewsin Neurobiology vol 15 no 2 pp 143ndash174 2003

[2] J Alonso M C Angermeyer S Bernert et al ldquoPrevalence ofmental disorders in Europe results from the European Study ofthe Epidemiology ofMental Disorders (ESEMeD) projectrdquoActaPsychiatrica Scandinavica Supplement vol 109 no 420 pp 21ndash27 2004

[3] T B Ustun J L Ayuso-Mateos S Chatterji C Mathers and CJ L Murray ldquoGlobal burden of depressive disorders in the year2000rdquo British Journal of Psychiatry vol 184 pp 386ndash392 2004

[4] H Gilmour and S B Patten ldquoDepression and work impair-mentrdquo Health Reports vol 18 no 1 pp 9ndash22 2007

[5] E Poleszak B Szewczyk E Kedzierska P Wlaz A Pilcand G Nowak ldquoAntidepressant- and anxiolytic-like activity ofmagnesium in micerdquo Pharmacology Biochemistry and Behaviorvol 78 no 1 pp 7ndash12 2004

[6] P Skolnick P Popik and R Trullas ldquoGlutamate-based antide-pressants 20 years onrdquo Trends in Pharmacological Sciences vol30 no 11 pp 563ndash569 2009

[7] J F Cryan A Markou and I Lucki ldquoAssessing antidepressantactivity in rodents recent developments and future needsrdquoTrends in Pharmacological Sciences vol 23 no 5 pp 238ndash2452002

[8] E J Nestler M Barrot R J DiLeone A J Eisch S J Gold andLMMonteggia ldquoNeurobiology of depressionrdquoNeuron vol 34no 1 pp 13ndash25 2002

[9] R Trullas and P Skolnick ldquoFunctional antagonists at theNMDA receptor complex exhibit antidepressant actionsrdquo Euro-pean Journal of Pharmacology vol 185 no 1 pp 1ndash10 1990

[10] M Siwek D Dudek I A Paul et al ldquoZinc supplementationaugments efficacy of imipramine in treatment resistant patientsa double blind placebo-controlled studyrdquo Journal of AffectiveDisorders vol 118 no 1ndash3 pp 187ndash195 2009

[11] R M Berman A Cappiello A Anand et al ldquoAntidepressanteffects of ketamine in depressed patientsrdquo Biological Psychiatryvol 47 no 4 pp 351ndash354 2000

[12] C A Zarate Jr N E Brutsche L Ibrahim et al ldquoReplicationof Ketaminersquos antidepressant efficacy in bipolar depression arandomized controlled add-on trialrdquo Biological Psychiatry vol71 no 11 pp 939ndash946 2012

[13] W-L Zhu S-J Wang M-M Liu et al ldquoGlycine siteN-methyl-D-aspartate receptor antagonist7-CTKA producesrapid antidepressant-like effects in male ratsrdquo Journal of Psychi-atry amp Neuroscience vol 38 no 5 pp 306ndash316 2013

[14] S Akhondzadeh and S H Abbasi ldquoHerbal medicine inthe treatment of Alzhelmerrsquos diseaserdquo American Journal ofAlzheimerrsquos Disease and other Dementias vol 21 no 2 pp 113ndash118 2006

[15] D P Briskin ldquoMedicinal plants and phytomedicines Linkingplant biochemistry and physiology to human healthrdquo PlantPhysiology vol 124 no 2 pp 507ndash514 2000

[16] R M Darwish and T A Aburjai ldquoEffect of ethnomedicinalplants used in folklore medicine in Jordan as antibiotic resis-tant inhibitors on Escherichia colirdquo BMC Complementary andAlternative Medicine vol 10 article 9 2010

[17] NRC Guideforthe Careand Useof Laboratory Animals TheNational Academies Press 1996

[18] R D Porsolt M Le Pichon and M Jalfre ldquoDepression a newanimal model sensitive to antidepressant treatmentsrdquo Naturevol 266 no 5604 pp 730ndash732 1977

[19] L Steru R Chermat B Thierry and P Simon ldquoThe tailsuspension test a new method for screening antidepressants inmicerdquo Psychopharmacology vol 85 no 3 pp 367ndash370 1985

[20] O F OrsquoLeary A J Bechtholt J J Crowley T E Hill M EPage and I Lucki ldquoDepletion of serotonin and catecholaminesblock the acute behavioral response to different classes ofantidepressant drugs in the mouse tail suspension testrdquo Psy-chopharmacology vol 192 no 3 pp 357ndash371 2007

[21] P L M van Giersbergen E van Duinkerken C G J SweepV M Wiegant J M van Ree and W de Jong ldquo120572-Methyldopainduces a naltrexone-insensitive antinociception and hypo-motility in ratsrdquo British Journal of Pharmacology vol 99 no 3pp 467ndash472 1990

[22] J F Cryan M E Page and I Lucki ldquoDifferential behav-ioral effects of the antidepressants reboxetine fluoxetine andmoclobemide in a modified forced swim test following chronictreatmentrdquo Psychopharmacology vol 182 no 3 pp 335ndash3442005

[23] B Petit-Demouliere F Chenu and M Bourin ldquoForced swim-ming test in mice a review of antidepressant activityrdquo Psy-chopharmacology vol 177 no 3 pp 245ndash255 2005

[24] P L Delgado H L Miller R M Salomon et al ldquoTryptophan-depletion challenge in depressed patients treated withdesipramine or fluoxetine implications for the role of

12 ISRN Pharmacology

serotonin in the mechanism of antidepressant actionrdquoBiological Psychiatry vol 46 no 2 pp 212ndash220 1999

[25] A L Eckeli F Dach and A L S Rodrigues ldquoAcute treatmentswith GMP produce antidepressant-like effects in micerdquo Neu-roReport vol 11 no 9 pp 1839ndash1843 2000

[26] E C Gavioli CW Vaughan GMarzola et al ldquoAntidepressant-like effects of the nociceptinorphanin FQ receptor antago-nist UFP-101 new evidence from rats and micerdquo Naunyn-Schmiedebergrsquos Archives of Pharmacology vol 369 no 6 pp547ndash553 2004

[27] M E Page M J Detke A Dalvi L G Kirby and I LuckildquoSerotonergic mediation of the effects of fluoxetine but notdesipramine in the rat forced swimming testrdquo Psychopharma-cology vol 147 no 2 pp 162ndash167 1999

[28] M E Page and I Lucki ldquoEffects of acute and chronic reboxetinetreatment on stress-inducedmonoamine efflux in the rat frontalcortexrdquo Neuropsychopharmacology vol 27 no 2 pp 237ndash2472002

[29] F P Bymaster W Zhang P A Carter et al ldquoFluoxetinebut not other selective serotonin uptake inhibitors increasesnorepinephrine and dopamine extracellular levels in prefrontalcortexrdquo Psychopharmacology vol 160 no 4 pp 353ndash361 2002

[30] D T Chau P V Rada K Kim R A Kosloff and B G HoebelldquoFluoxetine alleviates behavioral depression while decreasingacetylcholine release in the nucleus accumbens shellrdquoNeuropsy-chopharmacology vol 36 no 8 pp 1729ndash1737 2011

[31] S J Corne R W Pickering and B T Warner ldquoA methodfor assessing the effects of drugs on the central actions of5-hydroxytryptaminerdquo British Journal of Pharmacology andChemotherapy vol 20 pp 106ndash120 1963

[32] S Schreiber and C G Pick ldquoFluoxetine for blepharospasminteraction of serotonin and dopaminerdquo Journal of Nervous andMental Disease vol 183 no 11 pp 719ndash721 1995

[33] W D Essman A Singh and I Lucki ldquoSerotonergic propertiesof cocaine effects on a 5-HT2 receptor-mediated behavior andon extracellular concentrations of serotonin and dopaminerdquoPharmacology Biochemistry and Behavior vol 49 no 1 pp 107ndash113 1994

[34] L-F Xu W-J Chu X-Y Qing et al ldquoProtopine inhibits sero-tonin transporter and noradrenaline transporter and has theantidepressant-like effect in mice modelsrdquoNeuropharmacologyvol 50 no 8 pp 934ndash940 2006

[35] GWDeMuth and SHAckerman ldquo120572-Methyldopa and depres-sion a clinical study and review of the literaturerdquo AmericanJournal of Psychiatry vol 140 no 5 pp 534ndash538 1983

[36] J Ji J L Mcdermott and D E Dluzen ldquoSex differences inK+-evoked striatal dopamine output from superfused striataltissue fragments of reserpine-treated CD-1 micerdquo Journal ofNeuroendocrinology vol 19 no 9 pp 725ndash731 2007

[37] R R Metzger J M Brown V Sandoval et al ldquoInhibitoryeffect of reserpine ondopamine transporter functionrdquoEuropeanJournal of Pharmacology vol 456 no 1ndash3 pp 39ndash43 2002

[38] M Fukui R M Rodriguiz J Zhou et al ldquoVmat2 heterozygousmutant mice display a depressive-like phenotyperdquo Journal ofNeuroscience vol 27 no 39 pp 10520ndash10529 2007

[39] E Woode E Boakye-Gyasi N Amidu C Ansah and MDuwiejua ldquoAnxiolytic and antidepressant effects of a leafextract ofPalisota hirsutaK Schum (Commelinaceae) inmicerdquoInternational Journal of Pharmacology vol 6 no 1 pp 1ndash172010

[40] E Poleszak P Wlaz B Szewczyk et al ldquoA complexinteraction between glycineNMDA receptors andserotonergicnoradrenergic antidepressants in the forcedswim test in micerdquo Journal of Neural Transmission vol 118 no11 pp 1535ndash1546 2011

[41] E Berrocoso K Ikeda I Sora et al ldquoActive behavioursproduced by antidepressants and opioids in the mouse tailsuspension testrdquoThe International Journal of Neuropsychophar-macology vol 61 no 1 pp 151ndash162 2012

[42] J F Cryan and I Lucki ldquoAntidepressant-like behavioral effectsmediated by 5-hydroxytryptamine(2C) receptorsrdquo Journal ofPharmacology andExperimentalTherapeutics vol 295 no 3 pp1120ndash1126 2000

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Journal of

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Pharmaceutics

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MEDIATORSINFLAMMATION

of

ISRN Pharmacology 5

Freq

uenc

y10

8

6

4

2

0

Ctrl 10 30 100

lowast

MOE (mg kgminus1)

(a)

10 303

lowast

lowast

FLX (mg kgminus1)

(b)

10 303

lowast

lowastlowast

IMI (mg kgminus1)

(c)

Dur

atio

n (s

)

350

300

250

200

150

100

50

0

MobilityImmobility

Ctrl 10 30 100

daggerdagger daggerdagger

daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast lowastlowastlowast lowastlowastlowast

lowastlowastlowast lowastlowastlowast

lowastlowastlowast

MOE (mg kgminus1)

(d)

MobilityImmobility

10 303

daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

FLX (mg kgminus1)

(e)

MobilityImmobility

10 303

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

IMI (mg kgminus1)

(f)

Figure 2 Effect of the extract MOE (10 30 and 100mg kgminus1) fluoxetine FLX (3 10 and 30mg kgminus1) and imipramine IMI (3 10 and30mg kgminus1) treatment on the (a b and c) frequency of mobility and immobility and (d e and f) duration of mobility and immobility in theTST Data are presented as group means plusmn SEM lowastlowastlowast119875 lt 0001 lowastlowast119875 lt 001 compared to vehicle-treated group (one-way ANOVA followedby Newman Keulsrsquo test) daggerdaggerdagger119875 lt 0001 comparison effect and dose (two-way ANOVA followed by Bonferronirsquos test)

extract and fluoxetine increased swimming score which wasreversed with pCPA pretreatment further supporting theiraction on the serotoninergic system [27 30] Both MOE andfluoxetine did not affect mean climbing score suggesting thattheir behavioural effect may not depend on noradrenergicpathways

Further evidence suggesting that the extract enhances 5-HTneurotransmissionwas derived from its ability to increasehead twitch responses induced by 5-HTP The head twitchresponse (HTR) in rodents induced by 5-hydroxytryptophan(5-HTP) a precursor of 5-HT [31] is considered as a specificbehavioural model for the activation of serotoninergic neu-ron specifically 5-HT

2A receptors [32]Thus it can be inferredthat MOE may be acting via direct or indirect activation of5-HT2A receptors Fluoxetine also increased the frequency of

HTRsThis result is consistentwith a number of studieswherefluoxetine elicited similar responses [33 34]

The present experiments also examined the role of nora-drenaline and dopamine in the acute behavioural effects of

the extract in the modified FST by using drugs that interferewith their neurotransmitter synthesis or release Depletionwith 120572-methyldopa an L-aromatic amino acid decarboxylaseinhibitor that inhibits the biosynthesis of catecholamines and5-HT [35] failed to attenuate the behavioural effects of MOEand fluoxetine while that of imipramine was abolished Thissuggests that MOE may not be affected by the biosynthesisof noradrenaline or dopamine Moreover when vesicularpools were depleted by reserpine the decrease in immobilityelicited by MOE or fluoxetine was not affected Here againthe effect of imipramine was attenuated Reserpine is anirreversible inhibitor of the vesicular monoamine transporter2 (VMAT-2) which is located primarily within the CNS andis responsible for transporting monoamines from the cyto-plasm into secretory vesicles [36 37] Treatment with reser-pine therefore leads to depletion of vesicular monoaminestoresmdashboth serotonin and noradrenaline [38] suggestingboth serotonin and noradrenaline might be important inthe antidepressant effects of imipramine The inability of

6 ISRN Pharmacology

Ctrl 10 30 100

lowastlowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowastIm

mob

ility

tim

e (s)

100

80

60

40

20

0

Untreated120572-MD-treated

MOE (mg kgminus1)

(a)

lowast

lowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowastlowastlowastlowast

Untreated

3 10 30

120572-MD-treated

FLX (mg kgminus1)

(b)

lowast

daggerdagger

daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

Untreated

3 10 30

120572-MD-treated

IMI (mg kgminus1)

(c)

lowastlowast

lowastlowast lowastlowastlowastlowastlowast

lowastlowastlowastlowastlowastlowast

UntreatedReserpinised

Ctrl 10 30 100

Imm

obili

ty ti

me (

s)

100

80

60

40

20

0

MOE (mg kgminus1)

(d)

lowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowast

3 10 30

UntreatedReserpinised

FLX (mg kgminus1)

(e)

lowast

daggerdaggerdagger

daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

3 10 30

UntreatedReserpinised

IMI (mg kgminus1)

(f)

daggerdagger

lowastlowastlowastlowastlowast

lowastlowastlowastlowastlowastlowastlowastlowastlowastlowastlowastlowast

Untreated

120

Imm

obili

ty ti

me (

s)

100

80

60

40

20

0

Ctrl 10 30 100

120572-MDres-treated

MOE (mg kgminus1)

(g)

lowast

lowastlowastlowast

lowastlowastlowast lowastlowastlowast

lowastlowastlowastlowastlowastlowast

3 10 30

Untreated120572-MDres-treated

FLX (mg kgminus1)

(h)

lowastlowast

daggerdaggerdaggerdaggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

3 10 30

Untreated120572-MDres-treated

IMI (mg kgminus1)

(i)

Figure 3 Effects of (andashc) reserpine alone (dndashf) 120572-methyldopa 120572-MD alone or (gndashi) both reserpine and 120572-methyldopa on duration ofimmobility of MOE (10ndash100mg kgminus1 po) fluoxetine (3ndash30mg kgminus1 po) and imipramine (3ndash30mg kgminus1 po) treatment in the FST Dataare presented as mean plusmn SEM of 5 animals significantly different from control lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 by one-way ANOVA followed byNewman Keulsrsquo test dagger119875 lt 005 daggerdagger119875 lt 001 and daggerdaggerdagger119875 lt 0001 significant difference between treatment and dose (two-way ANOVA withBonferroni post hoc test)

ISRN Pharmacology 7

Ctrl 10 30 100

Imm

obili

ty ti

me (

s)

60

40

50

20

10

30

0

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

MOE (mg kgminus1)

(a)

3 10 30

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

FLX (mg kgminus1)

(b)

3 10 30

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowast lowastlowastlowast

lowastlowastlowast

dagger

IMI (mg kgminus1)

(c)

Swim

min

g tim

e (s)

40

50

20

10

30

0

Ctrl 10 30 100

daggerdaggerdagger daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast lowastlowastlowast

lowastlowastlowast

MOE (mg kgminus1)

(d)

3 10 30

daggerdaggerdagger

daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

lowastlowast

FLX (mg kgminus1)

(e)

3 10 30

lowast

IMI (mg kgminus1)

(f)

Clim

bing

tim

e (s)

40

50

20

10

30

0

Ctrl 10 30 100

UntreatedPCPA-treated

MOE (mg kgminus1)

(g)

3 10 30

dagger

dagger

lowastlowastlowast

UntreatedPCPA-treated

FLX (mg kgminus1)

(h)

3 10 30

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

UntreatedPCPA-treated

IMI (mg kgminus1)

(i)

Figure 4 Effects of pCPA (200mg kgminus1) pretreatment on the (andashc) mean immobility counts (dndashf) swimming counts and (gndashi) climbingcounts of oral doses of extract MOE (10ndash100mg kgminus1) fluoxetine FLX (3ndash30mg kgminus1) and IMI (3ndash30mg kgminus1) treated groups in the FSTData are presented as mean plusmn SEM significantly different from control lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 by Newman Keulsrsquo test daggerdaggerdagger119875 lt 0001(two-way ANOVA followed by Bonferronirsquos post test comparison between drug treatment and dose)

8 ISRN Pharmacology

0

0

5

5

10

10

15

15

20

20

25

25

30

30

Time (min)

Ctrl

Ctrl

10 30 100

160

120

80

40

0

35lowastlowast

lowastlowastlowast

lowastlowastlowast

Num

ber o

f hea

d tw

itche

s

AUC

MOEMOEMOE10mg kgminus1

30mg kgminus1100mg kgminus1

(a)

0 5 10 15 20 25 30

Time (min)Ctrl

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

0

5

10

15

20

25

30

35

Num

ber o

f hea

d tw

itche

sFLX

FLXFLX

Ctrl 3 10 30

160

120

80

40

0

AUC

3mg kgminus110mg kgminus130mg kgminus1

(b)

Figure 5 Effect of MOE (10ndash100mg kgminus1 po) and fluoxetine (3ndash30mg kgminus1 po) on the time course curve of head twitch response test andtheir corresponding AUCs (a and b) in the same test represented as bar graphs Data was presented as mean plusmn SEM (119899 = 6) lowastlowastlowast119875 lt 0001lowastlowast

119875 lt 001 compared to vehicle-treated group (one-way ANOVA followed by Newman Keulsrsquo test)

reserpine pretreatment to reverse the antidepressant effectsof the extract and fluoxetine however seems to suggest thatreserpine does not affect vesicular storage of 5-HT to thesame extent as that of noradrenaline In fact this assertionis consistent with the results obtained by OrsquoLeary et aland Woode et al [20 39]mdashthe former demonstrating thatreserpine at the dose used produced a 93 and 95 depletionof cortical noradrenaline and dopamine content respectivelyand a 78 depletion of 5-HT To inhibit synthesis as wellas deplete vesicular pools of noradrenaline and dopaminemice were pretreated with both reserpine and 120572-methyldopaResults were similar to effects observed when mice weretreated with reserpine alone The work published by OrsquoLearyet al [20] indicated that when reserpine was combined with120572-methyl para-tyrosine AMPT (NE and DA biosyntheticinhibitor) a depletion of cortical DA (95) NE (97) and 5-HT (78) was observedThe combination had only a modesteffect on NE and DA but failed to affect 5-HT Though 120572-methyldopa was used instead of the AMPT used by OrsquoLearyand colleagues the results from the combined effect ofreserpine and 120572-methyldopa did not differ significantly fromwhen reserpine was used alone Amore recent publication byWoode et al [39] used 120572-methyldopa and similar results wasobserved These results demonstrate that the antidepressanteffect of MOE may not be dependent on noradrenergicneurotransmission

Both clinical and preclinical studies support the antide-pressant activity of antagonists on functional glycineNMDAreceptor complex These compounds are thought to havelower side effect profiles compared to the competitive and

noncompetitive NMDA antagonists The effect of MOE onglutamatergic neurotransmission was assessed by pretreatingmice with d-serine (DS) a full agonist on glycineNMDAreceptors or d-cycloserine (DCS) a partial agonist onthese receptors In both the TST and FST DS reversedthe decline in immobility by MOE and fluoxetine but DCSpretreatment potentiated the decline demonstrating thatMOE may be acting as an antagonist on the glycineNMDAreceptor complex In contrast the decrease in immobilityof desipramine was reversed by DS but DCS had no effecton it This suggests that the antidepressant effect of bothserotonin and noradrenaline-based compounds depends onthe inhibition of the glycineNMDA receptor complex butthe enhancement of antidepressant activity depends on theserotoninergic pathway and not the noradrenaline pathway[40] This explains why the antidepressant effect of theextract fluoxetine and desipramine was abolished by d-serine but only the effect of the extract and fluoxetine(which act via serotoninergic pathway) was potentiated by d-cycloserine Moreover MOE increased curling score in theTST slightly (suggestive of opioidergic activity) though notsignificant Pretreatment with DCS significantly increasedcurling score of MOE but did not affect both FLX and DSPtreated groups DS pretreatment partially inhibited pedalingbehaviour byMOEbut totally in FLX andDSP treated groupsDCS pretreatment also inhibited pedaling behaviour byMOEand DSP but not FLX According to Berrocoso et al [41]opioids decrease immobility score while increasing curlingbehaviour in mice This suggests that the extract on its ownmay have little effect on opioidergic activity but may interact

ISRN Pharmacology 9

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

daggerdaggerdagger

daggerdaggerdagger

daggerdaggerdagger

Ctrl MOE FLX DSP

50

40

30

20

10

0

Imm

obili

ty ti

me (

s)

(a)

Ctrl MOE FLX DSP

50

40

30

20

10

0

Imm

obili

ty ti

me (

s)

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

daggerdaggerdagger

daggerdaggerdagger

(b)

lowast

lowastlowast

lowastlowastlowast

dagger

daggerdagger

30

25

20

15

10

5

0

Peda

lling

tim

e (s)

Ctrl MOE FLX DSP

(c)

lowast

lowast

lowast

daggerdaggerdagger

30

25

20

15

10

5

0

Peda

lling

tim

e (s)

Ctrl MOE FLX DSP

(d)

Ctrl MOE FLX DSP

UntreatedD-serine-treated

60

Curli

ng ti

me (

s)

50

40

30

20

10

0

lowastlowastlowast

daggerdagger

(e)

daggerdagger

Ctrl MOE FLX DSP

Untreated

60

Curli

ng ti

me (

s)

50

40

30

20

10

0

lowastlowastlowast

lowastlowast

D-cycloserine-treated

(f)

Figure 6 Effects of d-serine (DS) or d-cycloserine (DCS) pretreatment on (a b) mean immobility count (c d) pedalling count and (e f)curling count of extractMOE (100mg kgminus1) fluoxetine FLX (10mg kgminus1) anddesipramineDSP (10mg kgminus1) treatment in the tail suspensiontest (TST) Data are presented as Means plusmn SEM significantly different from control lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 by Newman Keulrsquos testSignificant difference between treatments dagger119875 lt 005 daggerdagger119875 lt 001 and daggerdaggerdagger119875 lt 0001

10 ISRN Pharmacology

Imm

obili

ty ti

me (

s)

60

50

40

30

20

10

0

Ctrl MOE FLX DSP

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

(a)

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

Imm

obili

ty ti

me (

s)

60

50

40

30

20

10

0

Ctrl MOE FLX DSP

daggerdagger

(b)

Swim

min

g tim

e (s)

80

60

40

20

0

Ctrl MOE FLX DSP

lowastlowastlowast lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

daggerdaggerdagger

(c)

Swim

min

g tim

e (s)

80

60

40

20

0

Ctrl MOE FLX DSP

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

daggerdaggerdagger

daggerdagger

lowastlowast

(d)

Clim

bing

tim

e (s)

50

40

30

20

10

8

6

4

2

0

lowastlowast

UntreatedD-serine-treated

lowast

lowast

Ctrl MOE FLX DSP

(e)

Clim

bing

tim

e (s)

50

40

30

20

10

8

6

4

2

0

lowastlowastlowastlowastlowastlowast

UntreatedD-cycloserine-treated

lowast

lowast

dagger

Ctrl MOE FLX DSP

(f)

Figure 7 Effects of d-serine (DS) or d-cycloserine (DCS) pretreatment on (a b) mean immobility count (c d) swimming count and (ef) climbing count of extract MOE (100mg kgminus1) fluoxetine FLX (10mg kgminus1) and desipramine DSP (10mg kgminus1) treatment in the forcedswimming test (FST) Data are presented as means plusmn SEM significantly different from control lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 by Newman Keulrsquostest Significant difference between treatments dagger119875 lt 005 daggerdagger119875 lt 001 and daggerdaggerdagger119875 lt 0001

ISRN Pharmacology 11

with opioid receptors when combined with DCS In the FSTMOE and FLX unlike DSP increased swimming behaviourwhich is sensitive to selective serotonin reuptake inhibitors(SSRIs) and 5HT agonists [22 42] This behavior exhibitedbyMOE and fluoxetine-treated mice was inhibited by DS butincreased byDCS pretreatment further supporting the theorythat antidepressant effect of serotonin based drugs dependson the inhibition of the glycineNMDA receptor complexand the enhancement of antidepressant activity dependson the serotoninergic pathway [40] Climbing scores weredecreased by both MOE and FLX and this was not affectedby both DS and DCS pretreatment This confirms theirlack of noradrenergic activity DSP a selective noradrenergicreuptake inhibitor on the contrary increased climbing scorewhich was unaffected by DCS pretreatment but decreasedby DS It is worth mentioning that the extract fluoxetinedesipramine alone or their combination with either d-serineor d-cycloserine did not impair motor coordination Thusthe behavioural effect observed can be attributed to drugtreatment alone

5 Conclusion

The present study shows that Mallotus oppositifolius hasantidepressant-like effect in mice and this may be mediatedvia enhancement of serotoninergic neurotransmission andinhibition of glycineNMDA receptor complex activationThe antidepressant effect of the extract may be devoid ofnoradrenergic mechanisms

Conflict of Interests

The authors declare that they have no conflict of interests

References

[1] P V Holmes ldquoRodent models of depression reexaminingvalidity without anthropomorphic inferencerdquo Critical Reviewsin Neurobiology vol 15 no 2 pp 143ndash174 2003

[2] J Alonso M C Angermeyer S Bernert et al ldquoPrevalence ofmental disorders in Europe results from the European Study ofthe Epidemiology ofMental Disorders (ESEMeD) projectrdquoActaPsychiatrica Scandinavica Supplement vol 109 no 420 pp 21ndash27 2004

[3] T B Ustun J L Ayuso-Mateos S Chatterji C Mathers and CJ L Murray ldquoGlobal burden of depressive disorders in the year2000rdquo British Journal of Psychiatry vol 184 pp 386ndash392 2004

[4] H Gilmour and S B Patten ldquoDepression and work impair-mentrdquo Health Reports vol 18 no 1 pp 9ndash22 2007

[5] E Poleszak B Szewczyk E Kedzierska P Wlaz A Pilcand G Nowak ldquoAntidepressant- and anxiolytic-like activity ofmagnesium in micerdquo Pharmacology Biochemistry and Behaviorvol 78 no 1 pp 7ndash12 2004

[6] P Skolnick P Popik and R Trullas ldquoGlutamate-based antide-pressants 20 years onrdquo Trends in Pharmacological Sciences vol30 no 11 pp 563ndash569 2009

[7] J F Cryan A Markou and I Lucki ldquoAssessing antidepressantactivity in rodents recent developments and future needsrdquoTrends in Pharmacological Sciences vol 23 no 5 pp 238ndash2452002

[8] E J Nestler M Barrot R J DiLeone A J Eisch S J Gold andLMMonteggia ldquoNeurobiology of depressionrdquoNeuron vol 34no 1 pp 13ndash25 2002

[9] R Trullas and P Skolnick ldquoFunctional antagonists at theNMDA receptor complex exhibit antidepressant actionsrdquo Euro-pean Journal of Pharmacology vol 185 no 1 pp 1ndash10 1990

[10] M Siwek D Dudek I A Paul et al ldquoZinc supplementationaugments efficacy of imipramine in treatment resistant patientsa double blind placebo-controlled studyrdquo Journal of AffectiveDisorders vol 118 no 1ndash3 pp 187ndash195 2009

[11] R M Berman A Cappiello A Anand et al ldquoAntidepressanteffects of ketamine in depressed patientsrdquo Biological Psychiatryvol 47 no 4 pp 351ndash354 2000

[12] C A Zarate Jr N E Brutsche L Ibrahim et al ldquoReplicationof Ketaminersquos antidepressant efficacy in bipolar depression arandomized controlled add-on trialrdquo Biological Psychiatry vol71 no 11 pp 939ndash946 2012

[13] W-L Zhu S-J Wang M-M Liu et al ldquoGlycine siteN-methyl-D-aspartate receptor antagonist7-CTKA producesrapid antidepressant-like effects in male ratsrdquo Journal of Psychi-atry amp Neuroscience vol 38 no 5 pp 306ndash316 2013

[14] S Akhondzadeh and S H Abbasi ldquoHerbal medicine inthe treatment of Alzhelmerrsquos diseaserdquo American Journal ofAlzheimerrsquos Disease and other Dementias vol 21 no 2 pp 113ndash118 2006

[15] D P Briskin ldquoMedicinal plants and phytomedicines Linkingplant biochemistry and physiology to human healthrdquo PlantPhysiology vol 124 no 2 pp 507ndash514 2000

[16] R M Darwish and T A Aburjai ldquoEffect of ethnomedicinalplants used in folklore medicine in Jordan as antibiotic resis-tant inhibitors on Escherichia colirdquo BMC Complementary andAlternative Medicine vol 10 article 9 2010

[17] NRC Guideforthe Careand Useof Laboratory Animals TheNational Academies Press 1996

[18] R D Porsolt M Le Pichon and M Jalfre ldquoDepression a newanimal model sensitive to antidepressant treatmentsrdquo Naturevol 266 no 5604 pp 730ndash732 1977

[19] L Steru R Chermat B Thierry and P Simon ldquoThe tailsuspension test a new method for screening antidepressants inmicerdquo Psychopharmacology vol 85 no 3 pp 367ndash370 1985

[20] O F OrsquoLeary A J Bechtholt J J Crowley T E Hill M EPage and I Lucki ldquoDepletion of serotonin and catecholaminesblock the acute behavioral response to different classes ofantidepressant drugs in the mouse tail suspension testrdquo Psy-chopharmacology vol 192 no 3 pp 357ndash371 2007

[21] P L M van Giersbergen E van Duinkerken C G J SweepV M Wiegant J M van Ree and W de Jong ldquo120572-Methyldopainduces a naltrexone-insensitive antinociception and hypo-motility in ratsrdquo British Journal of Pharmacology vol 99 no 3pp 467ndash472 1990

[22] J F Cryan M E Page and I Lucki ldquoDifferential behav-ioral effects of the antidepressants reboxetine fluoxetine andmoclobemide in a modified forced swim test following chronictreatmentrdquo Psychopharmacology vol 182 no 3 pp 335ndash3442005

[23] B Petit-Demouliere F Chenu and M Bourin ldquoForced swim-ming test in mice a review of antidepressant activityrdquo Psy-chopharmacology vol 177 no 3 pp 245ndash255 2005

[24] P L Delgado H L Miller R M Salomon et al ldquoTryptophan-depletion challenge in depressed patients treated withdesipramine or fluoxetine implications for the role of

12 ISRN Pharmacology

serotonin in the mechanism of antidepressant actionrdquoBiological Psychiatry vol 46 no 2 pp 212ndash220 1999

[25] A L Eckeli F Dach and A L S Rodrigues ldquoAcute treatmentswith GMP produce antidepressant-like effects in micerdquo Neu-roReport vol 11 no 9 pp 1839ndash1843 2000

[26] E C Gavioli CW Vaughan GMarzola et al ldquoAntidepressant-like effects of the nociceptinorphanin FQ receptor antago-nist UFP-101 new evidence from rats and micerdquo Naunyn-Schmiedebergrsquos Archives of Pharmacology vol 369 no 6 pp547ndash553 2004

[27] M E Page M J Detke A Dalvi L G Kirby and I LuckildquoSerotonergic mediation of the effects of fluoxetine but notdesipramine in the rat forced swimming testrdquo Psychopharma-cology vol 147 no 2 pp 162ndash167 1999

[28] M E Page and I Lucki ldquoEffects of acute and chronic reboxetinetreatment on stress-inducedmonoamine efflux in the rat frontalcortexrdquo Neuropsychopharmacology vol 27 no 2 pp 237ndash2472002

[29] F P Bymaster W Zhang P A Carter et al ldquoFluoxetinebut not other selective serotonin uptake inhibitors increasesnorepinephrine and dopamine extracellular levels in prefrontalcortexrdquo Psychopharmacology vol 160 no 4 pp 353ndash361 2002

[30] D T Chau P V Rada K Kim R A Kosloff and B G HoebelldquoFluoxetine alleviates behavioral depression while decreasingacetylcholine release in the nucleus accumbens shellrdquoNeuropsy-chopharmacology vol 36 no 8 pp 1729ndash1737 2011

[31] S J Corne R W Pickering and B T Warner ldquoA methodfor assessing the effects of drugs on the central actions of5-hydroxytryptaminerdquo British Journal of Pharmacology andChemotherapy vol 20 pp 106ndash120 1963

[32] S Schreiber and C G Pick ldquoFluoxetine for blepharospasminteraction of serotonin and dopaminerdquo Journal of Nervous andMental Disease vol 183 no 11 pp 719ndash721 1995

[33] W D Essman A Singh and I Lucki ldquoSerotonergic propertiesof cocaine effects on a 5-HT2 receptor-mediated behavior andon extracellular concentrations of serotonin and dopaminerdquoPharmacology Biochemistry and Behavior vol 49 no 1 pp 107ndash113 1994

[34] L-F Xu W-J Chu X-Y Qing et al ldquoProtopine inhibits sero-tonin transporter and noradrenaline transporter and has theantidepressant-like effect in mice modelsrdquoNeuropharmacologyvol 50 no 8 pp 934ndash940 2006

[35] GWDeMuth and SHAckerman ldquo120572-Methyldopa and depres-sion a clinical study and review of the literaturerdquo AmericanJournal of Psychiatry vol 140 no 5 pp 534ndash538 1983

[36] J Ji J L Mcdermott and D E Dluzen ldquoSex differences inK+-evoked striatal dopamine output from superfused striataltissue fragments of reserpine-treated CD-1 micerdquo Journal ofNeuroendocrinology vol 19 no 9 pp 725ndash731 2007

[37] R R Metzger J M Brown V Sandoval et al ldquoInhibitoryeffect of reserpine ondopamine transporter functionrdquoEuropeanJournal of Pharmacology vol 456 no 1ndash3 pp 39ndash43 2002

[38] M Fukui R M Rodriguiz J Zhou et al ldquoVmat2 heterozygousmutant mice display a depressive-like phenotyperdquo Journal ofNeuroscience vol 27 no 39 pp 10520ndash10529 2007

[39] E Woode E Boakye-Gyasi N Amidu C Ansah and MDuwiejua ldquoAnxiolytic and antidepressant effects of a leafextract ofPalisota hirsutaK Schum (Commelinaceae) inmicerdquoInternational Journal of Pharmacology vol 6 no 1 pp 1ndash172010

[40] E Poleszak P Wlaz B Szewczyk et al ldquoA complexinteraction between glycineNMDA receptors andserotonergicnoradrenergic antidepressants in the forcedswim test in micerdquo Journal of Neural Transmission vol 118 no11 pp 1535ndash1546 2011

[41] E Berrocoso K Ikeda I Sora et al ldquoActive behavioursproduced by antidepressants and opioids in the mouse tailsuspension testrdquoThe International Journal of Neuropsychophar-macology vol 61 no 1 pp 151ndash162 2012

[42] J F Cryan and I Lucki ldquoAntidepressant-like behavioral effectsmediated by 5-hydroxytryptamine(2C) receptorsrdquo Journal ofPharmacology andExperimentalTherapeutics vol 295 no 3 pp1120ndash1126 2000

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Journal of

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Pharmaceutics

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MEDIATORSINFLAMMATION

of

6 ISRN Pharmacology

Ctrl 10 30 100

lowastlowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowastIm

mob

ility

tim

e (s)

100

80

60

40

20

0

Untreated120572-MD-treated

MOE (mg kgminus1)

(a)

lowast

lowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowastlowastlowastlowast

Untreated

3 10 30

120572-MD-treated

FLX (mg kgminus1)

(b)

lowast

daggerdagger

daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

Untreated

3 10 30

120572-MD-treated

IMI (mg kgminus1)

(c)

lowastlowast

lowastlowast lowastlowastlowastlowastlowast

lowastlowastlowastlowastlowastlowast

UntreatedReserpinised

Ctrl 10 30 100

Imm

obili

ty ti

me (

s)

100

80

60

40

20

0

MOE (mg kgminus1)

(d)

lowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowast

3 10 30

UntreatedReserpinised

FLX (mg kgminus1)

(e)

lowast

daggerdaggerdagger

daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

3 10 30

UntreatedReserpinised

IMI (mg kgminus1)

(f)

daggerdagger

lowastlowastlowastlowastlowast

lowastlowastlowastlowastlowastlowastlowastlowastlowastlowastlowastlowast

Untreated

120

Imm

obili

ty ti

me (

s)

100

80

60

40

20

0

Ctrl 10 30 100

120572-MDres-treated

MOE (mg kgminus1)

(g)

lowast

lowastlowastlowast

lowastlowastlowast lowastlowastlowast

lowastlowastlowastlowastlowastlowast

3 10 30

Untreated120572-MDres-treated

FLX (mg kgminus1)

(h)

lowastlowast

daggerdaggerdaggerdaggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

3 10 30

Untreated120572-MDres-treated

IMI (mg kgminus1)

(i)

Figure 3 Effects of (andashc) reserpine alone (dndashf) 120572-methyldopa 120572-MD alone or (gndashi) both reserpine and 120572-methyldopa on duration ofimmobility of MOE (10ndash100mg kgminus1 po) fluoxetine (3ndash30mg kgminus1 po) and imipramine (3ndash30mg kgminus1 po) treatment in the FST Dataare presented as mean plusmn SEM of 5 animals significantly different from control lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 by one-way ANOVA followed byNewman Keulsrsquo test dagger119875 lt 005 daggerdagger119875 lt 001 and daggerdaggerdagger119875 lt 0001 significant difference between treatment and dose (two-way ANOVA withBonferroni post hoc test)

ISRN Pharmacology 7

Ctrl 10 30 100

Imm

obili

ty ti

me (

s)

60

40

50

20

10

30

0

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

MOE (mg kgminus1)

(a)

3 10 30

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

FLX (mg kgminus1)

(b)

3 10 30

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowast lowastlowastlowast

lowastlowastlowast

dagger

IMI (mg kgminus1)

(c)

Swim

min

g tim

e (s)

40

50

20

10

30

0

Ctrl 10 30 100

daggerdaggerdagger daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast lowastlowastlowast

lowastlowastlowast

MOE (mg kgminus1)

(d)

3 10 30

daggerdaggerdagger

daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

lowastlowast

FLX (mg kgminus1)

(e)

3 10 30

lowast

IMI (mg kgminus1)

(f)

Clim

bing

tim

e (s)

40

50

20

10

30

0

Ctrl 10 30 100

UntreatedPCPA-treated

MOE (mg kgminus1)

(g)

3 10 30

dagger

dagger

lowastlowastlowast

UntreatedPCPA-treated

FLX (mg kgminus1)

(h)

3 10 30

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

UntreatedPCPA-treated

IMI (mg kgminus1)

(i)

Figure 4 Effects of pCPA (200mg kgminus1) pretreatment on the (andashc) mean immobility counts (dndashf) swimming counts and (gndashi) climbingcounts of oral doses of extract MOE (10ndash100mg kgminus1) fluoxetine FLX (3ndash30mg kgminus1) and IMI (3ndash30mg kgminus1) treated groups in the FSTData are presented as mean plusmn SEM significantly different from control lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 by Newman Keulsrsquo test daggerdaggerdagger119875 lt 0001(two-way ANOVA followed by Bonferronirsquos post test comparison between drug treatment and dose)

8 ISRN Pharmacology

0

0

5

5

10

10

15

15

20

20

25

25

30

30

Time (min)

Ctrl

Ctrl

10 30 100

160

120

80

40

0

35lowastlowast

lowastlowastlowast

lowastlowastlowast

Num

ber o

f hea

d tw

itche

s

AUC

MOEMOEMOE10mg kgminus1

30mg kgminus1100mg kgminus1

(a)

0 5 10 15 20 25 30

Time (min)Ctrl

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

0

5

10

15

20

25

30

35

Num

ber o

f hea

d tw

itche

sFLX

FLXFLX

Ctrl 3 10 30

160

120

80

40

0

AUC

3mg kgminus110mg kgminus130mg kgminus1

(b)

Figure 5 Effect of MOE (10ndash100mg kgminus1 po) and fluoxetine (3ndash30mg kgminus1 po) on the time course curve of head twitch response test andtheir corresponding AUCs (a and b) in the same test represented as bar graphs Data was presented as mean plusmn SEM (119899 = 6) lowastlowastlowast119875 lt 0001lowastlowast

119875 lt 001 compared to vehicle-treated group (one-way ANOVA followed by Newman Keulsrsquo test)

reserpine pretreatment to reverse the antidepressant effectsof the extract and fluoxetine however seems to suggest thatreserpine does not affect vesicular storage of 5-HT to thesame extent as that of noradrenaline In fact this assertionis consistent with the results obtained by OrsquoLeary et aland Woode et al [20 39]mdashthe former demonstrating thatreserpine at the dose used produced a 93 and 95 depletionof cortical noradrenaline and dopamine content respectivelyand a 78 depletion of 5-HT To inhibit synthesis as wellas deplete vesicular pools of noradrenaline and dopaminemice were pretreated with both reserpine and 120572-methyldopaResults were similar to effects observed when mice weretreated with reserpine alone The work published by OrsquoLearyet al [20] indicated that when reserpine was combined with120572-methyl para-tyrosine AMPT (NE and DA biosyntheticinhibitor) a depletion of cortical DA (95) NE (97) and 5-HT (78) was observedThe combination had only a modesteffect on NE and DA but failed to affect 5-HT Though 120572-methyldopa was used instead of the AMPT used by OrsquoLearyand colleagues the results from the combined effect ofreserpine and 120572-methyldopa did not differ significantly fromwhen reserpine was used alone Amore recent publication byWoode et al [39] used 120572-methyldopa and similar results wasobserved These results demonstrate that the antidepressanteffect of MOE may not be dependent on noradrenergicneurotransmission

Both clinical and preclinical studies support the antide-pressant activity of antagonists on functional glycineNMDAreceptor complex These compounds are thought to havelower side effect profiles compared to the competitive and

noncompetitive NMDA antagonists The effect of MOE onglutamatergic neurotransmission was assessed by pretreatingmice with d-serine (DS) a full agonist on glycineNMDAreceptors or d-cycloserine (DCS) a partial agonist onthese receptors In both the TST and FST DS reversedthe decline in immobility by MOE and fluoxetine but DCSpretreatment potentiated the decline demonstrating thatMOE may be acting as an antagonist on the glycineNMDAreceptor complex In contrast the decrease in immobilityof desipramine was reversed by DS but DCS had no effecton it This suggests that the antidepressant effect of bothserotonin and noradrenaline-based compounds depends onthe inhibition of the glycineNMDA receptor complex butthe enhancement of antidepressant activity depends on theserotoninergic pathway and not the noradrenaline pathway[40] This explains why the antidepressant effect of theextract fluoxetine and desipramine was abolished by d-serine but only the effect of the extract and fluoxetine(which act via serotoninergic pathway) was potentiated by d-cycloserine Moreover MOE increased curling score in theTST slightly (suggestive of opioidergic activity) though notsignificant Pretreatment with DCS significantly increasedcurling score of MOE but did not affect both FLX and DSPtreated groups DS pretreatment partially inhibited pedalingbehaviour byMOEbut totally in FLX andDSP treated groupsDCS pretreatment also inhibited pedaling behaviour byMOEand DSP but not FLX According to Berrocoso et al [41]opioids decrease immobility score while increasing curlingbehaviour in mice This suggests that the extract on its ownmay have little effect on opioidergic activity but may interact

ISRN Pharmacology 9

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

daggerdaggerdagger

daggerdaggerdagger

daggerdaggerdagger

Ctrl MOE FLX DSP

50

40

30

20

10

0

Imm

obili

ty ti

me (

s)

(a)

Ctrl MOE FLX DSP

50

40

30

20

10

0

Imm

obili

ty ti

me (

s)

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

daggerdaggerdagger

daggerdaggerdagger

(b)

lowast

lowastlowast

lowastlowastlowast

dagger

daggerdagger

30

25

20

15

10

5

0

Peda

lling

tim

e (s)

Ctrl MOE FLX DSP

(c)

lowast

lowast

lowast

daggerdaggerdagger

30

25

20

15

10

5

0

Peda

lling

tim

e (s)

Ctrl MOE FLX DSP

(d)

Ctrl MOE FLX DSP

UntreatedD-serine-treated

60

Curli

ng ti

me (

s)

50

40

30

20

10

0

lowastlowastlowast

daggerdagger

(e)

daggerdagger

Ctrl MOE FLX DSP

Untreated

60

Curli

ng ti

me (

s)

50

40

30

20

10

0

lowastlowastlowast

lowastlowast

D-cycloserine-treated

(f)

Figure 6 Effects of d-serine (DS) or d-cycloserine (DCS) pretreatment on (a b) mean immobility count (c d) pedalling count and (e f)curling count of extractMOE (100mg kgminus1) fluoxetine FLX (10mg kgminus1) anddesipramineDSP (10mg kgminus1) treatment in the tail suspensiontest (TST) Data are presented as Means plusmn SEM significantly different from control lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 by Newman Keulrsquos testSignificant difference between treatments dagger119875 lt 005 daggerdagger119875 lt 001 and daggerdaggerdagger119875 lt 0001

10 ISRN Pharmacology

Imm

obili

ty ti

me (

s)

60

50

40

30

20

10

0

Ctrl MOE FLX DSP

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

(a)

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

Imm

obili

ty ti

me (

s)

60

50

40

30

20

10

0

Ctrl MOE FLX DSP

daggerdagger

(b)

Swim

min

g tim

e (s)

80

60

40

20

0

Ctrl MOE FLX DSP

lowastlowastlowast lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

daggerdaggerdagger

(c)

Swim

min

g tim

e (s)

80

60

40

20

0

Ctrl MOE FLX DSP

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

daggerdaggerdagger

daggerdagger

lowastlowast

(d)

Clim

bing

tim

e (s)

50

40

30

20

10

8

6

4

2

0

lowastlowast

UntreatedD-serine-treated

lowast

lowast

Ctrl MOE FLX DSP

(e)

Clim

bing

tim

e (s)

50

40

30

20

10

8

6

4

2

0

lowastlowastlowastlowastlowastlowast

UntreatedD-cycloserine-treated

lowast

lowast

dagger

Ctrl MOE FLX DSP

(f)

Figure 7 Effects of d-serine (DS) or d-cycloserine (DCS) pretreatment on (a b) mean immobility count (c d) swimming count and (ef) climbing count of extract MOE (100mg kgminus1) fluoxetine FLX (10mg kgminus1) and desipramine DSP (10mg kgminus1) treatment in the forcedswimming test (FST) Data are presented as means plusmn SEM significantly different from control lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 by Newman Keulrsquostest Significant difference between treatments dagger119875 lt 005 daggerdagger119875 lt 001 and daggerdaggerdagger119875 lt 0001

ISRN Pharmacology 11

with opioid receptors when combined with DCS In the FSTMOE and FLX unlike DSP increased swimming behaviourwhich is sensitive to selective serotonin reuptake inhibitors(SSRIs) and 5HT agonists [22 42] This behavior exhibitedbyMOE and fluoxetine-treated mice was inhibited by DS butincreased byDCS pretreatment further supporting the theorythat antidepressant effect of serotonin based drugs dependson the inhibition of the glycineNMDA receptor complexand the enhancement of antidepressant activity dependson the serotoninergic pathway [40] Climbing scores weredecreased by both MOE and FLX and this was not affectedby both DS and DCS pretreatment This confirms theirlack of noradrenergic activity DSP a selective noradrenergicreuptake inhibitor on the contrary increased climbing scorewhich was unaffected by DCS pretreatment but decreasedby DS It is worth mentioning that the extract fluoxetinedesipramine alone or their combination with either d-serineor d-cycloserine did not impair motor coordination Thusthe behavioural effect observed can be attributed to drugtreatment alone

5 Conclusion

The present study shows that Mallotus oppositifolius hasantidepressant-like effect in mice and this may be mediatedvia enhancement of serotoninergic neurotransmission andinhibition of glycineNMDA receptor complex activationThe antidepressant effect of the extract may be devoid ofnoradrenergic mechanisms

Conflict of Interests

The authors declare that they have no conflict of interests

References

[1] P V Holmes ldquoRodent models of depression reexaminingvalidity without anthropomorphic inferencerdquo Critical Reviewsin Neurobiology vol 15 no 2 pp 143ndash174 2003

[2] J Alonso M C Angermeyer S Bernert et al ldquoPrevalence ofmental disorders in Europe results from the European Study ofthe Epidemiology ofMental Disorders (ESEMeD) projectrdquoActaPsychiatrica Scandinavica Supplement vol 109 no 420 pp 21ndash27 2004

[3] T B Ustun J L Ayuso-Mateos S Chatterji C Mathers and CJ L Murray ldquoGlobal burden of depressive disorders in the year2000rdquo British Journal of Psychiatry vol 184 pp 386ndash392 2004

[4] H Gilmour and S B Patten ldquoDepression and work impair-mentrdquo Health Reports vol 18 no 1 pp 9ndash22 2007

[5] E Poleszak B Szewczyk E Kedzierska P Wlaz A Pilcand G Nowak ldquoAntidepressant- and anxiolytic-like activity ofmagnesium in micerdquo Pharmacology Biochemistry and Behaviorvol 78 no 1 pp 7ndash12 2004

[6] P Skolnick P Popik and R Trullas ldquoGlutamate-based antide-pressants 20 years onrdquo Trends in Pharmacological Sciences vol30 no 11 pp 563ndash569 2009

[7] J F Cryan A Markou and I Lucki ldquoAssessing antidepressantactivity in rodents recent developments and future needsrdquoTrends in Pharmacological Sciences vol 23 no 5 pp 238ndash2452002

[8] E J Nestler M Barrot R J DiLeone A J Eisch S J Gold andLMMonteggia ldquoNeurobiology of depressionrdquoNeuron vol 34no 1 pp 13ndash25 2002

[9] R Trullas and P Skolnick ldquoFunctional antagonists at theNMDA receptor complex exhibit antidepressant actionsrdquo Euro-pean Journal of Pharmacology vol 185 no 1 pp 1ndash10 1990

[10] M Siwek D Dudek I A Paul et al ldquoZinc supplementationaugments efficacy of imipramine in treatment resistant patientsa double blind placebo-controlled studyrdquo Journal of AffectiveDisorders vol 118 no 1ndash3 pp 187ndash195 2009

[11] R M Berman A Cappiello A Anand et al ldquoAntidepressanteffects of ketamine in depressed patientsrdquo Biological Psychiatryvol 47 no 4 pp 351ndash354 2000

[12] C A Zarate Jr N E Brutsche L Ibrahim et al ldquoReplicationof Ketaminersquos antidepressant efficacy in bipolar depression arandomized controlled add-on trialrdquo Biological Psychiatry vol71 no 11 pp 939ndash946 2012

[13] W-L Zhu S-J Wang M-M Liu et al ldquoGlycine siteN-methyl-D-aspartate receptor antagonist7-CTKA producesrapid antidepressant-like effects in male ratsrdquo Journal of Psychi-atry amp Neuroscience vol 38 no 5 pp 306ndash316 2013

[14] S Akhondzadeh and S H Abbasi ldquoHerbal medicine inthe treatment of Alzhelmerrsquos diseaserdquo American Journal ofAlzheimerrsquos Disease and other Dementias vol 21 no 2 pp 113ndash118 2006

[15] D P Briskin ldquoMedicinal plants and phytomedicines Linkingplant biochemistry and physiology to human healthrdquo PlantPhysiology vol 124 no 2 pp 507ndash514 2000

[16] R M Darwish and T A Aburjai ldquoEffect of ethnomedicinalplants used in folklore medicine in Jordan as antibiotic resis-tant inhibitors on Escherichia colirdquo BMC Complementary andAlternative Medicine vol 10 article 9 2010

[17] NRC Guideforthe Careand Useof Laboratory Animals TheNational Academies Press 1996

[18] R D Porsolt M Le Pichon and M Jalfre ldquoDepression a newanimal model sensitive to antidepressant treatmentsrdquo Naturevol 266 no 5604 pp 730ndash732 1977

[19] L Steru R Chermat B Thierry and P Simon ldquoThe tailsuspension test a new method for screening antidepressants inmicerdquo Psychopharmacology vol 85 no 3 pp 367ndash370 1985

[20] O F OrsquoLeary A J Bechtholt J J Crowley T E Hill M EPage and I Lucki ldquoDepletion of serotonin and catecholaminesblock the acute behavioral response to different classes ofantidepressant drugs in the mouse tail suspension testrdquo Psy-chopharmacology vol 192 no 3 pp 357ndash371 2007

[21] P L M van Giersbergen E van Duinkerken C G J SweepV M Wiegant J M van Ree and W de Jong ldquo120572-Methyldopainduces a naltrexone-insensitive antinociception and hypo-motility in ratsrdquo British Journal of Pharmacology vol 99 no 3pp 467ndash472 1990

[22] J F Cryan M E Page and I Lucki ldquoDifferential behav-ioral effects of the antidepressants reboxetine fluoxetine andmoclobemide in a modified forced swim test following chronictreatmentrdquo Psychopharmacology vol 182 no 3 pp 335ndash3442005

[23] B Petit-Demouliere F Chenu and M Bourin ldquoForced swim-ming test in mice a review of antidepressant activityrdquo Psy-chopharmacology vol 177 no 3 pp 245ndash255 2005

[24] P L Delgado H L Miller R M Salomon et al ldquoTryptophan-depletion challenge in depressed patients treated withdesipramine or fluoxetine implications for the role of

12 ISRN Pharmacology

serotonin in the mechanism of antidepressant actionrdquoBiological Psychiatry vol 46 no 2 pp 212ndash220 1999

[25] A L Eckeli F Dach and A L S Rodrigues ldquoAcute treatmentswith GMP produce antidepressant-like effects in micerdquo Neu-roReport vol 11 no 9 pp 1839ndash1843 2000

[26] E C Gavioli CW Vaughan GMarzola et al ldquoAntidepressant-like effects of the nociceptinorphanin FQ receptor antago-nist UFP-101 new evidence from rats and micerdquo Naunyn-Schmiedebergrsquos Archives of Pharmacology vol 369 no 6 pp547ndash553 2004

[27] M E Page M J Detke A Dalvi L G Kirby and I LuckildquoSerotonergic mediation of the effects of fluoxetine but notdesipramine in the rat forced swimming testrdquo Psychopharma-cology vol 147 no 2 pp 162ndash167 1999

[28] M E Page and I Lucki ldquoEffects of acute and chronic reboxetinetreatment on stress-inducedmonoamine efflux in the rat frontalcortexrdquo Neuropsychopharmacology vol 27 no 2 pp 237ndash2472002

[29] F P Bymaster W Zhang P A Carter et al ldquoFluoxetinebut not other selective serotonin uptake inhibitors increasesnorepinephrine and dopamine extracellular levels in prefrontalcortexrdquo Psychopharmacology vol 160 no 4 pp 353ndash361 2002

[30] D T Chau P V Rada K Kim R A Kosloff and B G HoebelldquoFluoxetine alleviates behavioral depression while decreasingacetylcholine release in the nucleus accumbens shellrdquoNeuropsy-chopharmacology vol 36 no 8 pp 1729ndash1737 2011

[31] S J Corne R W Pickering and B T Warner ldquoA methodfor assessing the effects of drugs on the central actions of5-hydroxytryptaminerdquo British Journal of Pharmacology andChemotherapy vol 20 pp 106ndash120 1963

[32] S Schreiber and C G Pick ldquoFluoxetine for blepharospasminteraction of serotonin and dopaminerdquo Journal of Nervous andMental Disease vol 183 no 11 pp 719ndash721 1995

[33] W D Essman A Singh and I Lucki ldquoSerotonergic propertiesof cocaine effects on a 5-HT2 receptor-mediated behavior andon extracellular concentrations of serotonin and dopaminerdquoPharmacology Biochemistry and Behavior vol 49 no 1 pp 107ndash113 1994

[34] L-F Xu W-J Chu X-Y Qing et al ldquoProtopine inhibits sero-tonin transporter and noradrenaline transporter and has theantidepressant-like effect in mice modelsrdquoNeuropharmacologyvol 50 no 8 pp 934ndash940 2006

[35] GWDeMuth and SHAckerman ldquo120572-Methyldopa and depres-sion a clinical study and review of the literaturerdquo AmericanJournal of Psychiatry vol 140 no 5 pp 534ndash538 1983

[36] J Ji J L Mcdermott and D E Dluzen ldquoSex differences inK+-evoked striatal dopamine output from superfused striataltissue fragments of reserpine-treated CD-1 micerdquo Journal ofNeuroendocrinology vol 19 no 9 pp 725ndash731 2007

[37] R R Metzger J M Brown V Sandoval et al ldquoInhibitoryeffect of reserpine ondopamine transporter functionrdquoEuropeanJournal of Pharmacology vol 456 no 1ndash3 pp 39ndash43 2002

[38] M Fukui R M Rodriguiz J Zhou et al ldquoVmat2 heterozygousmutant mice display a depressive-like phenotyperdquo Journal ofNeuroscience vol 27 no 39 pp 10520ndash10529 2007

[39] E Woode E Boakye-Gyasi N Amidu C Ansah and MDuwiejua ldquoAnxiolytic and antidepressant effects of a leafextract ofPalisota hirsutaK Schum (Commelinaceae) inmicerdquoInternational Journal of Pharmacology vol 6 no 1 pp 1ndash172010

[40] E Poleszak P Wlaz B Szewczyk et al ldquoA complexinteraction between glycineNMDA receptors andserotonergicnoradrenergic antidepressants in the forcedswim test in micerdquo Journal of Neural Transmission vol 118 no11 pp 1535ndash1546 2011

[41] E Berrocoso K Ikeda I Sora et al ldquoActive behavioursproduced by antidepressants and opioids in the mouse tailsuspension testrdquoThe International Journal of Neuropsychophar-macology vol 61 no 1 pp 151ndash162 2012

[42] J F Cryan and I Lucki ldquoAntidepressant-like behavioral effectsmediated by 5-hydroxytryptamine(2C) receptorsrdquo Journal ofPharmacology andExperimentalTherapeutics vol 295 no 3 pp1120ndash1126 2000

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Pharmaceutics

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MEDIATORSINFLAMMATION

of

ISRN Pharmacology 7

Ctrl 10 30 100

Imm

obili

ty ti

me (

s)

60

40

50

20

10

30

0

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

MOE (mg kgminus1)

(a)

3 10 30

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

FLX (mg kgminus1)

(b)

3 10 30

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

lowastlowastlowast lowastlowastlowast

lowastlowastlowast

dagger

IMI (mg kgminus1)

(c)

Swim

min

g tim

e (s)

40

50

20

10

30

0

Ctrl 10 30 100

daggerdaggerdagger daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast lowastlowastlowast

lowastlowastlowast

MOE (mg kgminus1)

(d)

3 10 30

daggerdaggerdagger

daggerdaggerdagger

daggerdaggerdagger

lowastlowastlowast

lowastlowastlowast

lowastlowast

FLX (mg kgminus1)

(e)

3 10 30

lowast

IMI (mg kgminus1)

(f)

Clim

bing

tim

e (s)

40

50

20

10

30

0

Ctrl 10 30 100

UntreatedPCPA-treated

MOE (mg kgminus1)

(g)

3 10 30

dagger

dagger

lowastlowastlowast

UntreatedPCPA-treated

FLX (mg kgminus1)

(h)

3 10 30

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

UntreatedPCPA-treated

IMI (mg kgminus1)

(i)

Figure 4 Effects of pCPA (200mg kgminus1) pretreatment on the (andashc) mean immobility counts (dndashf) swimming counts and (gndashi) climbingcounts of oral doses of extract MOE (10ndash100mg kgminus1) fluoxetine FLX (3ndash30mg kgminus1) and IMI (3ndash30mg kgminus1) treated groups in the FSTData are presented as mean plusmn SEM significantly different from control lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 by Newman Keulsrsquo test daggerdaggerdagger119875 lt 0001(two-way ANOVA followed by Bonferronirsquos post test comparison between drug treatment and dose)

8 ISRN Pharmacology

0

0

5

5

10

10

15

15

20

20

25

25

30

30

Time (min)

Ctrl

Ctrl

10 30 100

160

120

80

40

0

35lowastlowast

lowastlowastlowast

lowastlowastlowast

Num

ber o

f hea

d tw

itche

s

AUC

MOEMOEMOE10mg kgminus1

30mg kgminus1100mg kgminus1

(a)

0 5 10 15 20 25 30

Time (min)Ctrl

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

0

5

10

15

20

25

30

35

Num

ber o

f hea

d tw

itche

sFLX

FLXFLX

Ctrl 3 10 30

160

120

80

40

0

AUC

3mg kgminus110mg kgminus130mg kgminus1

(b)

Figure 5 Effect of MOE (10ndash100mg kgminus1 po) and fluoxetine (3ndash30mg kgminus1 po) on the time course curve of head twitch response test andtheir corresponding AUCs (a and b) in the same test represented as bar graphs Data was presented as mean plusmn SEM (119899 = 6) lowastlowastlowast119875 lt 0001lowastlowast

119875 lt 001 compared to vehicle-treated group (one-way ANOVA followed by Newman Keulsrsquo test)

reserpine pretreatment to reverse the antidepressant effectsof the extract and fluoxetine however seems to suggest thatreserpine does not affect vesicular storage of 5-HT to thesame extent as that of noradrenaline In fact this assertionis consistent with the results obtained by OrsquoLeary et aland Woode et al [20 39]mdashthe former demonstrating thatreserpine at the dose used produced a 93 and 95 depletionof cortical noradrenaline and dopamine content respectivelyand a 78 depletion of 5-HT To inhibit synthesis as wellas deplete vesicular pools of noradrenaline and dopaminemice were pretreated with both reserpine and 120572-methyldopaResults were similar to effects observed when mice weretreated with reserpine alone The work published by OrsquoLearyet al [20] indicated that when reserpine was combined with120572-methyl para-tyrosine AMPT (NE and DA biosyntheticinhibitor) a depletion of cortical DA (95) NE (97) and 5-HT (78) was observedThe combination had only a modesteffect on NE and DA but failed to affect 5-HT Though 120572-methyldopa was used instead of the AMPT used by OrsquoLearyand colleagues the results from the combined effect ofreserpine and 120572-methyldopa did not differ significantly fromwhen reserpine was used alone Amore recent publication byWoode et al [39] used 120572-methyldopa and similar results wasobserved These results demonstrate that the antidepressanteffect of MOE may not be dependent on noradrenergicneurotransmission

Both clinical and preclinical studies support the antide-pressant activity of antagonists on functional glycineNMDAreceptor complex These compounds are thought to havelower side effect profiles compared to the competitive and

noncompetitive NMDA antagonists The effect of MOE onglutamatergic neurotransmission was assessed by pretreatingmice with d-serine (DS) a full agonist on glycineNMDAreceptors or d-cycloserine (DCS) a partial agonist onthese receptors In both the TST and FST DS reversedthe decline in immobility by MOE and fluoxetine but DCSpretreatment potentiated the decline demonstrating thatMOE may be acting as an antagonist on the glycineNMDAreceptor complex In contrast the decrease in immobilityof desipramine was reversed by DS but DCS had no effecton it This suggests that the antidepressant effect of bothserotonin and noradrenaline-based compounds depends onthe inhibition of the glycineNMDA receptor complex butthe enhancement of antidepressant activity depends on theserotoninergic pathway and not the noradrenaline pathway[40] This explains why the antidepressant effect of theextract fluoxetine and desipramine was abolished by d-serine but only the effect of the extract and fluoxetine(which act via serotoninergic pathway) was potentiated by d-cycloserine Moreover MOE increased curling score in theTST slightly (suggestive of opioidergic activity) though notsignificant Pretreatment with DCS significantly increasedcurling score of MOE but did not affect both FLX and DSPtreated groups DS pretreatment partially inhibited pedalingbehaviour byMOEbut totally in FLX andDSP treated groupsDCS pretreatment also inhibited pedaling behaviour byMOEand DSP but not FLX According to Berrocoso et al [41]opioids decrease immobility score while increasing curlingbehaviour in mice This suggests that the extract on its ownmay have little effect on opioidergic activity but may interact

ISRN Pharmacology 9

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

daggerdaggerdagger

daggerdaggerdagger

daggerdaggerdagger

Ctrl MOE FLX DSP

50

40

30

20

10

0

Imm

obili

ty ti

me (

s)

(a)

Ctrl MOE FLX DSP

50

40

30

20

10

0

Imm

obili

ty ti

me (

s)

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

daggerdaggerdagger

daggerdaggerdagger

(b)

lowast

lowastlowast

lowastlowastlowast

dagger

daggerdagger

30

25

20

15

10

5

0

Peda

lling

tim

e (s)

Ctrl MOE FLX DSP

(c)

lowast

lowast

lowast

daggerdaggerdagger

30

25

20

15

10

5

0

Peda

lling

tim

e (s)

Ctrl MOE FLX DSP

(d)

Ctrl MOE FLX DSP

UntreatedD-serine-treated

60

Curli

ng ti

me (

s)

50

40

30

20

10

0

lowastlowastlowast

daggerdagger

(e)

daggerdagger

Ctrl MOE FLX DSP

Untreated

60

Curli

ng ti

me (

s)

50

40

30

20

10

0

lowastlowastlowast

lowastlowast

D-cycloserine-treated

(f)

Figure 6 Effects of d-serine (DS) or d-cycloserine (DCS) pretreatment on (a b) mean immobility count (c d) pedalling count and (e f)curling count of extractMOE (100mg kgminus1) fluoxetine FLX (10mg kgminus1) anddesipramineDSP (10mg kgminus1) treatment in the tail suspensiontest (TST) Data are presented as Means plusmn SEM significantly different from control lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 by Newman Keulrsquos testSignificant difference between treatments dagger119875 lt 005 daggerdagger119875 lt 001 and daggerdaggerdagger119875 lt 0001

10 ISRN Pharmacology

Imm

obili

ty ti

me (

s)

60

50

40

30

20

10

0

Ctrl MOE FLX DSP

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

(a)

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

Imm

obili

ty ti

me (

s)

60

50

40

30

20

10

0

Ctrl MOE FLX DSP

daggerdagger

(b)

Swim

min

g tim

e (s)

80

60

40

20

0

Ctrl MOE FLX DSP

lowastlowastlowast lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

daggerdaggerdagger

(c)

Swim

min

g tim

e (s)

80

60

40

20

0

Ctrl MOE FLX DSP

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

daggerdaggerdagger

daggerdagger

lowastlowast

(d)

Clim

bing

tim

e (s)

50

40

30

20

10

8

6

4

2

0

lowastlowast

UntreatedD-serine-treated

lowast

lowast

Ctrl MOE FLX DSP

(e)

Clim

bing

tim

e (s)

50

40

30

20

10

8

6

4

2

0

lowastlowastlowastlowastlowastlowast

UntreatedD-cycloserine-treated

lowast

lowast

dagger

Ctrl MOE FLX DSP

(f)

Figure 7 Effects of d-serine (DS) or d-cycloserine (DCS) pretreatment on (a b) mean immobility count (c d) swimming count and (ef) climbing count of extract MOE (100mg kgminus1) fluoxetine FLX (10mg kgminus1) and desipramine DSP (10mg kgminus1) treatment in the forcedswimming test (FST) Data are presented as means plusmn SEM significantly different from control lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 by Newman Keulrsquostest Significant difference between treatments dagger119875 lt 005 daggerdagger119875 lt 001 and daggerdaggerdagger119875 lt 0001

ISRN Pharmacology 11

with opioid receptors when combined with DCS In the FSTMOE and FLX unlike DSP increased swimming behaviourwhich is sensitive to selective serotonin reuptake inhibitors(SSRIs) and 5HT agonists [22 42] This behavior exhibitedbyMOE and fluoxetine-treated mice was inhibited by DS butincreased byDCS pretreatment further supporting the theorythat antidepressant effect of serotonin based drugs dependson the inhibition of the glycineNMDA receptor complexand the enhancement of antidepressant activity dependson the serotoninergic pathway [40] Climbing scores weredecreased by both MOE and FLX and this was not affectedby both DS and DCS pretreatment This confirms theirlack of noradrenergic activity DSP a selective noradrenergicreuptake inhibitor on the contrary increased climbing scorewhich was unaffected by DCS pretreatment but decreasedby DS It is worth mentioning that the extract fluoxetinedesipramine alone or their combination with either d-serineor d-cycloserine did not impair motor coordination Thusthe behavioural effect observed can be attributed to drugtreatment alone

5 Conclusion

The present study shows that Mallotus oppositifolius hasantidepressant-like effect in mice and this may be mediatedvia enhancement of serotoninergic neurotransmission andinhibition of glycineNMDA receptor complex activationThe antidepressant effect of the extract may be devoid ofnoradrenergic mechanisms

Conflict of Interests

The authors declare that they have no conflict of interests

References

[1] P V Holmes ldquoRodent models of depression reexaminingvalidity without anthropomorphic inferencerdquo Critical Reviewsin Neurobiology vol 15 no 2 pp 143ndash174 2003

[2] J Alonso M C Angermeyer S Bernert et al ldquoPrevalence ofmental disorders in Europe results from the European Study ofthe Epidemiology ofMental Disorders (ESEMeD) projectrdquoActaPsychiatrica Scandinavica Supplement vol 109 no 420 pp 21ndash27 2004

[3] T B Ustun J L Ayuso-Mateos S Chatterji C Mathers and CJ L Murray ldquoGlobal burden of depressive disorders in the year2000rdquo British Journal of Psychiatry vol 184 pp 386ndash392 2004

[4] H Gilmour and S B Patten ldquoDepression and work impair-mentrdquo Health Reports vol 18 no 1 pp 9ndash22 2007

[5] E Poleszak B Szewczyk E Kedzierska P Wlaz A Pilcand G Nowak ldquoAntidepressant- and anxiolytic-like activity ofmagnesium in micerdquo Pharmacology Biochemistry and Behaviorvol 78 no 1 pp 7ndash12 2004

[6] P Skolnick P Popik and R Trullas ldquoGlutamate-based antide-pressants 20 years onrdquo Trends in Pharmacological Sciences vol30 no 11 pp 563ndash569 2009

[7] J F Cryan A Markou and I Lucki ldquoAssessing antidepressantactivity in rodents recent developments and future needsrdquoTrends in Pharmacological Sciences vol 23 no 5 pp 238ndash2452002

[8] E J Nestler M Barrot R J DiLeone A J Eisch S J Gold andLMMonteggia ldquoNeurobiology of depressionrdquoNeuron vol 34no 1 pp 13ndash25 2002

[9] R Trullas and P Skolnick ldquoFunctional antagonists at theNMDA receptor complex exhibit antidepressant actionsrdquo Euro-pean Journal of Pharmacology vol 185 no 1 pp 1ndash10 1990

[10] M Siwek D Dudek I A Paul et al ldquoZinc supplementationaugments efficacy of imipramine in treatment resistant patientsa double blind placebo-controlled studyrdquo Journal of AffectiveDisorders vol 118 no 1ndash3 pp 187ndash195 2009

[11] R M Berman A Cappiello A Anand et al ldquoAntidepressanteffects of ketamine in depressed patientsrdquo Biological Psychiatryvol 47 no 4 pp 351ndash354 2000

[12] C A Zarate Jr N E Brutsche L Ibrahim et al ldquoReplicationof Ketaminersquos antidepressant efficacy in bipolar depression arandomized controlled add-on trialrdquo Biological Psychiatry vol71 no 11 pp 939ndash946 2012

[13] W-L Zhu S-J Wang M-M Liu et al ldquoGlycine siteN-methyl-D-aspartate receptor antagonist7-CTKA producesrapid antidepressant-like effects in male ratsrdquo Journal of Psychi-atry amp Neuroscience vol 38 no 5 pp 306ndash316 2013

[14] S Akhondzadeh and S H Abbasi ldquoHerbal medicine inthe treatment of Alzhelmerrsquos diseaserdquo American Journal ofAlzheimerrsquos Disease and other Dementias vol 21 no 2 pp 113ndash118 2006

[15] D P Briskin ldquoMedicinal plants and phytomedicines Linkingplant biochemistry and physiology to human healthrdquo PlantPhysiology vol 124 no 2 pp 507ndash514 2000

[16] R M Darwish and T A Aburjai ldquoEffect of ethnomedicinalplants used in folklore medicine in Jordan as antibiotic resis-tant inhibitors on Escherichia colirdquo BMC Complementary andAlternative Medicine vol 10 article 9 2010

[17] NRC Guideforthe Careand Useof Laboratory Animals TheNational Academies Press 1996

[18] R D Porsolt M Le Pichon and M Jalfre ldquoDepression a newanimal model sensitive to antidepressant treatmentsrdquo Naturevol 266 no 5604 pp 730ndash732 1977

[19] L Steru R Chermat B Thierry and P Simon ldquoThe tailsuspension test a new method for screening antidepressants inmicerdquo Psychopharmacology vol 85 no 3 pp 367ndash370 1985

[20] O F OrsquoLeary A J Bechtholt J J Crowley T E Hill M EPage and I Lucki ldquoDepletion of serotonin and catecholaminesblock the acute behavioral response to different classes ofantidepressant drugs in the mouse tail suspension testrdquo Psy-chopharmacology vol 192 no 3 pp 357ndash371 2007

[21] P L M van Giersbergen E van Duinkerken C G J SweepV M Wiegant J M van Ree and W de Jong ldquo120572-Methyldopainduces a naltrexone-insensitive antinociception and hypo-motility in ratsrdquo British Journal of Pharmacology vol 99 no 3pp 467ndash472 1990

[22] J F Cryan M E Page and I Lucki ldquoDifferential behav-ioral effects of the antidepressants reboxetine fluoxetine andmoclobemide in a modified forced swim test following chronictreatmentrdquo Psychopharmacology vol 182 no 3 pp 335ndash3442005

[23] B Petit-Demouliere F Chenu and M Bourin ldquoForced swim-ming test in mice a review of antidepressant activityrdquo Psy-chopharmacology vol 177 no 3 pp 245ndash255 2005

[24] P L Delgado H L Miller R M Salomon et al ldquoTryptophan-depletion challenge in depressed patients treated withdesipramine or fluoxetine implications for the role of

12 ISRN Pharmacology

serotonin in the mechanism of antidepressant actionrdquoBiological Psychiatry vol 46 no 2 pp 212ndash220 1999

[25] A L Eckeli F Dach and A L S Rodrigues ldquoAcute treatmentswith GMP produce antidepressant-like effects in micerdquo Neu-roReport vol 11 no 9 pp 1839ndash1843 2000

[26] E C Gavioli CW Vaughan GMarzola et al ldquoAntidepressant-like effects of the nociceptinorphanin FQ receptor antago-nist UFP-101 new evidence from rats and micerdquo Naunyn-Schmiedebergrsquos Archives of Pharmacology vol 369 no 6 pp547ndash553 2004

[27] M E Page M J Detke A Dalvi L G Kirby and I LuckildquoSerotonergic mediation of the effects of fluoxetine but notdesipramine in the rat forced swimming testrdquo Psychopharma-cology vol 147 no 2 pp 162ndash167 1999

[28] M E Page and I Lucki ldquoEffects of acute and chronic reboxetinetreatment on stress-inducedmonoamine efflux in the rat frontalcortexrdquo Neuropsychopharmacology vol 27 no 2 pp 237ndash2472002

[29] F P Bymaster W Zhang P A Carter et al ldquoFluoxetinebut not other selective serotonin uptake inhibitors increasesnorepinephrine and dopamine extracellular levels in prefrontalcortexrdquo Psychopharmacology vol 160 no 4 pp 353ndash361 2002

[30] D T Chau P V Rada K Kim R A Kosloff and B G HoebelldquoFluoxetine alleviates behavioral depression while decreasingacetylcholine release in the nucleus accumbens shellrdquoNeuropsy-chopharmacology vol 36 no 8 pp 1729ndash1737 2011

[31] S J Corne R W Pickering and B T Warner ldquoA methodfor assessing the effects of drugs on the central actions of5-hydroxytryptaminerdquo British Journal of Pharmacology andChemotherapy vol 20 pp 106ndash120 1963

[32] S Schreiber and C G Pick ldquoFluoxetine for blepharospasminteraction of serotonin and dopaminerdquo Journal of Nervous andMental Disease vol 183 no 11 pp 719ndash721 1995

[33] W D Essman A Singh and I Lucki ldquoSerotonergic propertiesof cocaine effects on a 5-HT2 receptor-mediated behavior andon extracellular concentrations of serotonin and dopaminerdquoPharmacology Biochemistry and Behavior vol 49 no 1 pp 107ndash113 1994

[34] L-F Xu W-J Chu X-Y Qing et al ldquoProtopine inhibits sero-tonin transporter and noradrenaline transporter and has theantidepressant-like effect in mice modelsrdquoNeuropharmacologyvol 50 no 8 pp 934ndash940 2006

[35] GWDeMuth and SHAckerman ldquo120572-Methyldopa and depres-sion a clinical study and review of the literaturerdquo AmericanJournal of Psychiatry vol 140 no 5 pp 534ndash538 1983

[36] J Ji J L Mcdermott and D E Dluzen ldquoSex differences inK+-evoked striatal dopamine output from superfused striataltissue fragments of reserpine-treated CD-1 micerdquo Journal ofNeuroendocrinology vol 19 no 9 pp 725ndash731 2007

[37] R R Metzger J M Brown V Sandoval et al ldquoInhibitoryeffect of reserpine ondopamine transporter functionrdquoEuropeanJournal of Pharmacology vol 456 no 1ndash3 pp 39ndash43 2002

[38] M Fukui R M Rodriguiz J Zhou et al ldquoVmat2 heterozygousmutant mice display a depressive-like phenotyperdquo Journal ofNeuroscience vol 27 no 39 pp 10520ndash10529 2007

[39] E Woode E Boakye-Gyasi N Amidu C Ansah and MDuwiejua ldquoAnxiolytic and antidepressant effects of a leafextract ofPalisota hirsutaK Schum (Commelinaceae) inmicerdquoInternational Journal of Pharmacology vol 6 no 1 pp 1ndash172010

[40] E Poleszak P Wlaz B Szewczyk et al ldquoA complexinteraction between glycineNMDA receptors andserotonergicnoradrenergic antidepressants in the forcedswim test in micerdquo Journal of Neural Transmission vol 118 no11 pp 1535ndash1546 2011

[41] E Berrocoso K Ikeda I Sora et al ldquoActive behavioursproduced by antidepressants and opioids in the mouse tailsuspension testrdquoThe International Journal of Neuropsychophar-macology vol 61 no 1 pp 151ndash162 2012

[42] J F Cryan and I Lucki ldquoAntidepressant-like behavioral effectsmediated by 5-hydroxytryptamine(2C) receptorsrdquo Journal ofPharmacology andExperimentalTherapeutics vol 295 no 3 pp1120ndash1126 2000

Submit your manuscripts athttpwwwhindawicom

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ToxinsJournal of

VaccinesJournal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

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AntibioticsInternational Journal of

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Drug DeliveryJournal of

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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in Pharmacological Sciences

Tropical MedicineJournal of

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Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

AddictionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Anesthesiology Research and Practice

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Journal of

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Pharmaceutics

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MEDIATORSINFLAMMATION

of

8 ISRN Pharmacology

0

0

5

5

10

10

15

15

20

20

25

25

30

30

Time (min)

Ctrl

Ctrl

10 30 100

160

120

80

40

0

35lowastlowast

lowastlowastlowast

lowastlowastlowast

Num

ber o

f hea

d tw

itche

s

AUC

MOEMOEMOE10mg kgminus1

30mg kgminus1100mg kgminus1

(a)

0 5 10 15 20 25 30

Time (min)Ctrl

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

0

5

10

15

20

25

30

35

Num

ber o

f hea

d tw

itche

sFLX

FLXFLX

Ctrl 3 10 30

160

120

80

40

0

AUC

3mg kgminus110mg kgminus130mg kgminus1

(b)

Figure 5 Effect of MOE (10ndash100mg kgminus1 po) and fluoxetine (3ndash30mg kgminus1 po) on the time course curve of head twitch response test andtheir corresponding AUCs (a and b) in the same test represented as bar graphs Data was presented as mean plusmn SEM (119899 = 6) lowastlowastlowast119875 lt 0001lowastlowast

119875 lt 001 compared to vehicle-treated group (one-way ANOVA followed by Newman Keulsrsquo test)

reserpine pretreatment to reverse the antidepressant effectsof the extract and fluoxetine however seems to suggest thatreserpine does not affect vesicular storage of 5-HT to thesame extent as that of noradrenaline In fact this assertionis consistent with the results obtained by OrsquoLeary et aland Woode et al [20 39]mdashthe former demonstrating thatreserpine at the dose used produced a 93 and 95 depletionof cortical noradrenaline and dopamine content respectivelyand a 78 depletion of 5-HT To inhibit synthesis as wellas deplete vesicular pools of noradrenaline and dopaminemice were pretreated with both reserpine and 120572-methyldopaResults were similar to effects observed when mice weretreated with reserpine alone The work published by OrsquoLearyet al [20] indicated that when reserpine was combined with120572-methyl para-tyrosine AMPT (NE and DA biosyntheticinhibitor) a depletion of cortical DA (95) NE (97) and 5-HT (78) was observedThe combination had only a modesteffect on NE and DA but failed to affect 5-HT Though 120572-methyldopa was used instead of the AMPT used by OrsquoLearyand colleagues the results from the combined effect ofreserpine and 120572-methyldopa did not differ significantly fromwhen reserpine was used alone Amore recent publication byWoode et al [39] used 120572-methyldopa and similar results wasobserved These results demonstrate that the antidepressanteffect of MOE may not be dependent on noradrenergicneurotransmission

Both clinical and preclinical studies support the antide-pressant activity of antagonists on functional glycineNMDAreceptor complex These compounds are thought to havelower side effect profiles compared to the competitive and

noncompetitive NMDA antagonists The effect of MOE onglutamatergic neurotransmission was assessed by pretreatingmice with d-serine (DS) a full agonist on glycineNMDAreceptors or d-cycloserine (DCS) a partial agonist onthese receptors In both the TST and FST DS reversedthe decline in immobility by MOE and fluoxetine but DCSpretreatment potentiated the decline demonstrating thatMOE may be acting as an antagonist on the glycineNMDAreceptor complex In contrast the decrease in immobilityof desipramine was reversed by DS but DCS had no effecton it This suggests that the antidepressant effect of bothserotonin and noradrenaline-based compounds depends onthe inhibition of the glycineNMDA receptor complex butthe enhancement of antidepressant activity depends on theserotoninergic pathway and not the noradrenaline pathway[40] This explains why the antidepressant effect of theextract fluoxetine and desipramine was abolished by d-serine but only the effect of the extract and fluoxetine(which act via serotoninergic pathway) was potentiated by d-cycloserine Moreover MOE increased curling score in theTST slightly (suggestive of opioidergic activity) though notsignificant Pretreatment with DCS significantly increasedcurling score of MOE but did not affect both FLX and DSPtreated groups DS pretreatment partially inhibited pedalingbehaviour byMOEbut totally in FLX andDSP treated groupsDCS pretreatment also inhibited pedaling behaviour byMOEand DSP but not FLX According to Berrocoso et al [41]opioids decrease immobility score while increasing curlingbehaviour in mice This suggests that the extract on its ownmay have little effect on opioidergic activity but may interact

ISRN Pharmacology 9

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

daggerdaggerdagger

daggerdaggerdagger

daggerdaggerdagger

Ctrl MOE FLX DSP

50

40

30

20

10

0

Imm

obili

ty ti

me (

s)

(a)

Ctrl MOE FLX DSP

50

40

30

20

10

0

Imm

obili

ty ti

me (

s)

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

daggerdaggerdagger

daggerdaggerdagger

(b)

lowast

lowastlowast

lowastlowastlowast

dagger

daggerdagger

30

25

20

15

10

5

0

Peda

lling

tim

e (s)

Ctrl MOE FLX DSP

(c)

lowast

lowast

lowast

daggerdaggerdagger

30

25

20

15

10

5

0

Peda

lling

tim

e (s)

Ctrl MOE FLX DSP

(d)

Ctrl MOE FLX DSP

UntreatedD-serine-treated

60

Curli

ng ti

me (

s)

50

40

30

20

10

0

lowastlowastlowast

daggerdagger

(e)

daggerdagger

Ctrl MOE FLX DSP

Untreated

60

Curli

ng ti

me (

s)

50

40

30

20

10

0

lowastlowastlowast

lowastlowast

D-cycloserine-treated

(f)

Figure 6 Effects of d-serine (DS) or d-cycloserine (DCS) pretreatment on (a b) mean immobility count (c d) pedalling count and (e f)curling count of extractMOE (100mg kgminus1) fluoxetine FLX (10mg kgminus1) anddesipramineDSP (10mg kgminus1) treatment in the tail suspensiontest (TST) Data are presented as Means plusmn SEM significantly different from control lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 by Newman Keulrsquos testSignificant difference between treatments dagger119875 lt 005 daggerdagger119875 lt 001 and daggerdaggerdagger119875 lt 0001

10 ISRN Pharmacology

Imm

obili

ty ti

me (

s)

60

50

40

30

20

10

0

Ctrl MOE FLX DSP

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

(a)

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

Imm

obili

ty ti

me (

s)

60

50

40

30

20

10

0

Ctrl MOE FLX DSP

daggerdagger

(b)

Swim

min

g tim

e (s)

80

60

40

20

0

Ctrl MOE FLX DSP

lowastlowastlowast lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

daggerdaggerdagger

(c)

Swim

min

g tim

e (s)

80

60

40

20

0

Ctrl MOE FLX DSP

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

daggerdaggerdagger

daggerdagger

lowastlowast

(d)

Clim

bing

tim

e (s)

50

40

30

20

10

8

6

4

2

0

lowastlowast

UntreatedD-serine-treated

lowast

lowast

Ctrl MOE FLX DSP

(e)

Clim

bing

tim

e (s)

50

40

30

20

10

8

6

4

2

0

lowastlowastlowastlowastlowastlowast

UntreatedD-cycloserine-treated

lowast

lowast

dagger

Ctrl MOE FLX DSP

(f)

Figure 7 Effects of d-serine (DS) or d-cycloserine (DCS) pretreatment on (a b) mean immobility count (c d) swimming count and (ef) climbing count of extract MOE (100mg kgminus1) fluoxetine FLX (10mg kgminus1) and desipramine DSP (10mg kgminus1) treatment in the forcedswimming test (FST) Data are presented as means plusmn SEM significantly different from control lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 by Newman Keulrsquostest Significant difference between treatments dagger119875 lt 005 daggerdagger119875 lt 001 and daggerdaggerdagger119875 lt 0001

ISRN Pharmacology 11

with opioid receptors when combined with DCS In the FSTMOE and FLX unlike DSP increased swimming behaviourwhich is sensitive to selective serotonin reuptake inhibitors(SSRIs) and 5HT agonists [22 42] This behavior exhibitedbyMOE and fluoxetine-treated mice was inhibited by DS butincreased byDCS pretreatment further supporting the theorythat antidepressant effect of serotonin based drugs dependson the inhibition of the glycineNMDA receptor complexand the enhancement of antidepressant activity dependson the serotoninergic pathway [40] Climbing scores weredecreased by both MOE and FLX and this was not affectedby both DS and DCS pretreatment This confirms theirlack of noradrenergic activity DSP a selective noradrenergicreuptake inhibitor on the contrary increased climbing scorewhich was unaffected by DCS pretreatment but decreasedby DS It is worth mentioning that the extract fluoxetinedesipramine alone or their combination with either d-serineor d-cycloserine did not impair motor coordination Thusthe behavioural effect observed can be attributed to drugtreatment alone

5 Conclusion

The present study shows that Mallotus oppositifolius hasantidepressant-like effect in mice and this may be mediatedvia enhancement of serotoninergic neurotransmission andinhibition of glycineNMDA receptor complex activationThe antidepressant effect of the extract may be devoid ofnoradrenergic mechanisms

Conflict of Interests

The authors declare that they have no conflict of interests

References

[1] P V Holmes ldquoRodent models of depression reexaminingvalidity without anthropomorphic inferencerdquo Critical Reviewsin Neurobiology vol 15 no 2 pp 143ndash174 2003

[2] J Alonso M C Angermeyer S Bernert et al ldquoPrevalence ofmental disorders in Europe results from the European Study ofthe Epidemiology ofMental Disorders (ESEMeD) projectrdquoActaPsychiatrica Scandinavica Supplement vol 109 no 420 pp 21ndash27 2004

[3] T B Ustun J L Ayuso-Mateos S Chatterji C Mathers and CJ L Murray ldquoGlobal burden of depressive disorders in the year2000rdquo British Journal of Psychiatry vol 184 pp 386ndash392 2004

[4] H Gilmour and S B Patten ldquoDepression and work impair-mentrdquo Health Reports vol 18 no 1 pp 9ndash22 2007

[5] E Poleszak B Szewczyk E Kedzierska P Wlaz A Pilcand G Nowak ldquoAntidepressant- and anxiolytic-like activity ofmagnesium in micerdquo Pharmacology Biochemistry and Behaviorvol 78 no 1 pp 7ndash12 2004

[6] P Skolnick P Popik and R Trullas ldquoGlutamate-based antide-pressants 20 years onrdquo Trends in Pharmacological Sciences vol30 no 11 pp 563ndash569 2009

[7] J F Cryan A Markou and I Lucki ldquoAssessing antidepressantactivity in rodents recent developments and future needsrdquoTrends in Pharmacological Sciences vol 23 no 5 pp 238ndash2452002

[8] E J Nestler M Barrot R J DiLeone A J Eisch S J Gold andLMMonteggia ldquoNeurobiology of depressionrdquoNeuron vol 34no 1 pp 13ndash25 2002

[9] R Trullas and P Skolnick ldquoFunctional antagonists at theNMDA receptor complex exhibit antidepressant actionsrdquo Euro-pean Journal of Pharmacology vol 185 no 1 pp 1ndash10 1990

[10] M Siwek D Dudek I A Paul et al ldquoZinc supplementationaugments efficacy of imipramine in treatment resistant patientsa double blind placebo-controlled studyrdquo Journal of AffectiveDisorders vol 118 no 1ndash3 pp 187ndash195 2009

[11] R M Berman A Cappiello A Anand et al ldquoAntidepressanteffects of ketamine in depressed patientsrdquo Biological Psychiatryvol 47 no 4 pp 351ndash354 2000

[12] C A Zarate Jr N E Brutsche L Ibrahim et al ldquoReplicationof Ketaminersquos antidepressant efficacy in bipolar depression arandomized controlled add-on trialrdquo Biological Psychiatry vol71 no 11 pp 939ndash946 2012

[13] W-L Zhu S-J Wang M-M Liu et al ldquoGlycine siteN-methyl-D-aspartate receptor antagonist7-CTKA producesrapid antidepressant-like effects in male ratsrdquo Journal of Psychi-atry amp Neuroscience vol 38 no 5 pp 306ndash316 2013

[14] S Akhondzadeh and S H Abbasi ldquoHerbal medicine inthe treatment of Alzhelmerrsquos diseaserdquo American Journal ofAlzheimerrsquos Disease and other Dementias vol 21 no 2 pp 113ndash118 2006

[15] D P Briskin ldquoMedicinal plants and phytomedicines Linkingplant biochemistry and physiology to human healthrdquo PlantPhysiology vol 124 no 2 pp 507ndash514 2000

[16] R M Darwish and T A Aburjai ldquoEffect of ethnomedicinalplants used in folklore medicine in Jordan as antibiotic resis-tant inhibitors on Escherichia colirdquo BMC Complementary andAlternative Medicine vol 10 article 9 2010

[17] NRC Guideforthe Careand Useof Laboratory Animals TheNational Academies Press 1996

[18] R D Porsolt M Le Pichon and M Jalfre ldquoDepression a newanimal model sensitive to antidepressant treatmentsrdquo Naturevol 266 no 5604 pp 730ndash732 1977

[19] L Steru R Chermat B Thierry and P Simon ldquoThe tailsuspension test a new method for screening antidepressants inmicerdquo Psychopharmacology vol 85 no 3 pp 367ndash370 1985

[20] O F OrsquoLeary A J Bechtholt J J Crowley T E Hill M EPage and I Lucki ldquoDepletion of serotonin and catecholaminesblock the acute behavioral response to different classes ofantidepressant drugs in the mouse tail suspension testrdquo Psy-chopharmacology vol 192 no 3 pp 357ndash371 2007

[21] P L M van Giersbergen E van Duinkerken C G J SweepV M Wiegant J M van Ree and W de Jong ldquo120572-Methyldopainduces a naltrexone-insensitive antinociception and hypo-motility in ratsrdquo British Journal of Pharmacology vol 99 no 3pp 467ndash472 1990

[22] J F Cryan M E Page and I Lucki ldquoDifferential behav-ioral effects of the antidepressants reboxetine fluoxetine andmoclobemide in a modified forced swim test following chronictreatmentrdquo Psychopharmacology vol 182 no 3 pp 335ndash3442005

[23] B Petit-Demouliere F Chenu and M Bourin ldquoForced swim-ming test in mice a review of antidepressant activityrdquo Psy-chopharmacology vol 177 no 3 pp 245ndash255 2005

[24] P L Delgado H L Miller R M Salomon et al ldquoTryptophan-depletion challenge in depressed patients treated withdesipramine or fluoxetine implications for the role of

12 ISRN Pharmacology

serotonin in the mechanism of antidepressant actionrdquoBiological Psychiatry vol 46 no 2 pp 212ndash220 1999

[25] A L Eckeli F Dach and A L S Rodrigues ldquoAcute treatmentswith GMP produce antidepressant-like effects in micerdquo Neu-roReport vol 11 no 9 pp 1839ndash1843 2000

[26] E C Gavioli CW Vaughan GMarzola et al ldquoAntidepressant-like effects of the nociceptinorphanin FQ receptor antago-nist UFP-101 new evidence from rats and micerdquo Naunyn-Schmiedebergrsquos Archives of Pharmacology vol 369 no 6 pp547ndash553 2004

[27] M E Page M J Detke A Dalvi L G Kirby and I LuckildquoSerotonergic mediation of the effects of fluoxetine but notdesipramine in the rat forced swimming testrdquo Psychopharma-cology vol 147 no 2 pp 162ndash167 1999

[28] M E Page and I Lucki ldquoEffects of acute and chronic reboxetinetreatment on stress-inducedmonoamine efflux in the rat frontalcortexrdquo Neuropsychopharmacology vol 27 no 2 pp 237ndash2472002

[29] F P Bymaster W Zhang P A Carter et al ldquoFluoxetinebut not other selective serotonin uptake inhibitors increasesnorepinephrine and dopamine extracellular levels in prefrontalcortexrdquo Psychopharmacology vol 160 no 4 pp 353ndash361 2002

[30] D T Chau P V Rada K Kim R A Kosloff and B G HoebelldquoFluoxetine alleviates behavioral depression while decreasingacetylcholine release in the nucleus accumbens shellrdquoNeuropsy-chopharmacology vol 36 no 8 pp 1729ndash1737 2011

[31] S J Corne R W Pickering and B T Warner ldquoA methodfor assessing the effects of drugs on the central actions of5-hydroxytryptaminerdquo British Journal of Pharmacology andChemotherapy vol 20 pp 106ndash120 1963

[32] S Schreiber and C G Pick ldquoFluoxetine for blepharospasminteraction of serotonin and dopaminerdquo Journal of Nervous andMental Disease vol 183 no 11 pp 719ndash721 1995

[33] W D Essman A Singh and I Lucki ldquoSerotonergic propertiesof cocaine effects on a 5-HT2 receptor-mediated behavior andon extracellular concentrations of serotonin and dopaminerdquoPharmacology Biochemistry and Behavior vol 49 no 1 pp 107ndash113 1994

[34] L-F Xu W-J Chu X-Y Qing et al ldquoProtopine inhibits sero-tonin transporter and noradrenaline transporter and has theantidepressant-like effect in mice modelsrdquoNeuropharmacologyvol 50 no 8 pp 934ndash940 2006

[35] GWDeMuth and SHAckerman ldquo120572-Methyldopa and depres-sion a clinical study and review of the literaturerdquo AmericanJournal of Psychiatry vol 140 no 5 pp 534ndash538 1983

[36] J Ji J L Mcdermott and D E Dluzen ldquoSex differences inK+-evoked striatal dopamine output from superfused striataltissue fragments of reserpine-treated CD-1 micerdquo Journal ofNeuroendocrinology vol 19 no 9 pp 725ndash731 2007

[37] R R Metzger J M Brown V Sandoval et al ldquoInhibitoryeffect of reserpine ondopamine transporter functionrdquoEuropeanJournal of Pharmacology vol 456 no 1ndash3 pp 39ndash43 2002

[38] M Fukui R M Rodriguiz J Zhou et al ldquoVmat2 heterozygousmutant mice display a depressive-like phenotyperdquo Journal ofNeuroscience vol 27 no 39 pp 10520ndash10529 2007

[39] E Woode E Boakye-Gyasi N Amidu C Ansah and MDuwiejua ldquoAnxiolytic and antidepressant effects of a leafextract ofPalisota hirsutaK Schum (Commelinaceae) inmicerdquoInternational Journal of Pharmacology vol 6 no 1 pp 1ndash172010

[40] E Poleszak P Wlaz B Szewczyk et al ldquoA complexinteraction between glycineNMDA receptors andserotonergicnoradrenergic antidepressants in the forcedswim test in micerdquo Journal of Neural Transmission vol 118 no11 pp 1535ndash1546 2011

[41] E Berrocoso K Ikeda I Sora et al ldquoActive behavioursproduced by antidepressants and opioids in the mouse tailsuspension testrdquoThe International Journal of Neuropsychophar-macology vol 61 no 1 pp 151ndash162 2012

[42] J F Cryan and I Lucki ldquoAntidepressant-like behavioral effectsmediated by 5-hydroxytryptamine(2C) receptorsrdquo Journal ofPharmacology andExperimentalTherapeutics vol 295 no 3 pp1120ndash1126 2000

Submit your manuscripts athttpwwwhindawicom

PainResearch and TreatmentHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom

Volume 2014

ToxinsJournal of

VaccinesJournal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

AntibioticsInternational Journal of

ToxicologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

StrokeResearch and TreatmentHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Drug DeliveryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in Pharmacological Sciences

Tropical MedicineJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

AddictionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

Emergency Medicine InternationalHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Autoimmune Diseases

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Anesthesiology Research and Practice

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Pharmaceutics

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MEDIATORSINFLAMMATION

of

ISRN Pharmacology 9

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

daggerdaggerdagger

daggerdaggerdagger

daggerdaggerdagger

Ctrl MOE FLX DSP

50

40

30

20

10

0

Imm

obili

ty ti

me (

s)

(a)

Ctrl MOE FLX DSP

50

40

30

20

10

0

Imm

obili

ty ti

me (

s)

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

daggerdaggerdagger

daggerdaggerdagger

(b)

lowast

lowastlowast

lowastlowastlowast

dagger

daggerdagger

30

25

20

15

10

5

0

Peda

lling

tim

e (s)

Ctrl MOE FLX DSP

(c)

lowast

lowast

lowast

daggerdaggerdagger

30

25

20

15

10

5

0

Peda

lling

tim

e (s)

Ctrl MOE FLX DSP

(d)

Ctrl MOE FLX DSP

UntreatedD-serine-treated

60

Curli

ng ti

me (

s)

50

40

30

20

10

0

lowastlowastlowast

daggerdagger

(e)

daggerdagger

Ctrl MOE FLX DSP

Untreated

60

Curli

ng ti

me (

s)

50

40

30

20

10

0

lowastlowastlowast

lowastlowast

D-cycloserine-treated

(f)

Figure 6 Effects of d-serine (DS) or d-cycloserine (DCS) pretreatment on (a b) mean immobility count (c d) pedalling count and (e f)curling count of extractMOE (100mg kgminus1) fluoxetine FLX (10mg kgminus1) anddesipramineDSP (10mg kgminus1) treatment in the tail suspensiontest (TST) Data are presented as Means plusmn SEM significantly different from control lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 by Newman Keulrsquos testSignificant difference between treatments dagger119875 lt 005 daggerdagger119875 lt 001 and daggerdaggerdagger119875 lt 0001

10 ISRN Pharmacology

Imm

obili

ty ti

me (

s)

60

50

40

30

20

10

0

Ctrl MOE FLX DSP

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

(a)

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

Imm

obili

ty ti

me (

s)

60

50

40

30

20

10

0

Ctrl MOE FLX DSP

daggerdagger

(b)

Swim

min

g tim

e (s)

80

60

40

20

0

Ctrl MOE FLX DSP

lowastlowastlowast lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

daggerdaggerdagger

(c)

Swim

min

g tim

e (s)

80

60

40

20

0

Ctrl MOE FLX DSP

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

daggerdaggerdagger

daggerdagger

lowastlowast

(d)

Clim

bing

tim

e (s)

50

40

30

20

10

8

6

4

2

0

lowastlowast

UntreatedD-serine-treated

lowast

lowast

Ctrl MOE FLX DSP

(e)

Clim

bing

tim

e (s)

50

40

30

20

10

8

6

4

2

0

lowastlowastlowastlowastlowastlowast

UntreatedD-cycloserine-treated

lowast

lowast

dagger

Ctrl MOE FLX DSP

(f)

Figure 7 Effects of d-serine (DS) or d-cycloserine (DCS) pretreatment on (a b) mean immobility count (c d) swimming count and (ef) climbing count of extract MOE (100mg kgminus1) fluoxetine FLX (10mg kgminus1) and desipramine DSP (10mg kgminus1) treatment in the forcedswimming test (FST) Data are presented as means plusmn SEM significantly different from control lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 by Newman Keulrsquostest Significant difference between treatments dagger119875 lt 005 daggerdagger119875 lt 001 and daggerdaggerdagger119875 lt 0001

ISRN Pharmacology 11

with opioid receptors when combined with DCS In the FSTMOE and FLX unlike DSP increased swimming behaviourwhich is sensitive to selective serotonin reuptake inhibitors(SSRIs) and 5HT agonists [22 42] This behavior exhibitedbyMOE and fluoxetine-treated mice was inhibited by DS butincreased byDCS pretreatment further supporting the theorythat antidepressant effect of serotonin based drugs dependson the inhibition of the glycineNMDA receptor complexand the enhancement of antidepressant activity dependson the serotoninergic pathway [40] Climbing scores weredecreased by both MOE and FLX and this was not affectedby both DS and DCS pretreatment This confirms theirlack of noradrenergic activity DSP a selective noradrenergicreuptake inhibitor on the contrary increased climbing scorewhich was unaffected by DCS pretreatment but decreasedby DS It is worth mentioning that the extract fluoxetinedesipramine alone or their combination with either d-serineor d-cycloserine did not impair motor coordination Thusthe behavioural effect observed can be attributed to drugtreatment alone

5 Conclusion

The present study shows that Mallotus oppositifolius hasantidepressant-like effect in mice and this may be mediatedvia enhancement of serotoninergic neurotransmission andinhibition of glycineNMDA receptor complex activationThe antidepressant effect of the extract may be devoid ofnoradrenergic mechanisms

Conflict of Interests

The authors declare that they have no conflict of interests

References

[1] P V Holmes ldquoRodent models of depression reexaminingvalidity without anthropomorphic inferencerdquo Critical Reviewsin Neurobiology vol 15 no 2 pp 143ndash174 2003

[2] J Alonso M C Angermeyer S Bernert et al ldquoPrevalence ofmental disorders in Europe results from the European Study ofthe Epidemiology ofMental Disorders (ESEMeD) projectrdquoActaPsychiatrica Scandinavica Supplement vol 109 no 420 pp 21ndash27 2004

[3] T B Ustun J L Ayuso-Mateos S Chatterji C Mathers and CJ L Murray ldquoGlobal burden of depressive disorders in the year2000rdquo British Journal of Psychiatry vol 184 pp 386ndash392 2004

[4] H Gilmour and S B Patten ldquoDepression and work impair-mentrdquo Health Reports vol 18 no 1 pp 9ndash22 2007

[5] E Poleszak B Szewczyk E Kedzierska P Wlaz A Pilcand G Nowak ldquoAntidepressant- and anxiolytic-like activity ofmagnesium in micerdquo Pharmacology Biochemistry and Behaviorvol 78 no 1 pp 7ndash12 2004

[6] P Skolnick P Popik and R Trullas ldquoGlutamate-based antide-pressants 20 years onrdquo Trends in Pharmacological Sciences vol30 no 11 pp 563ndash569 2009

[7] J F Cryan A Markou and I Lucki ldquoAssessing antidepressantactivity in rodents recent developments and future needsrdquoTrends in Pharmacological Sciences vol 23 no 5 pp 238ndash2452002

[8] E J Nestler M Barrot R J DiLeone A J Eisch S J Gold andLMMonteggia ldquoNeurobiology of depressionrdquoNeuron vol 34no 1 pp 13ndash25 2002

[9] R Trullas and P Skolnick ldquoFunctional antagonists at theNMDA receptor complex exhibit antidepressant actionsrdquo Euro-pean Journal of Pharmacology vol 185 no 1 pp 1ndash10 1990

[10] M Siwek D Dudek I A Paul et al ldquoZinc supplementationaugments efficacy of imipramine in treatment resistant patientsa double blind placebo-controlled studyrdquo Journal of AffectiveDisorders vol 118 no 1ndash3 pp 187ndash195 2009

[11] R M Berman A Cappiello A Anand et al ldquoAntidepressanteffects of ketamine in depressed patientsrdquo Biological Psychiatryvol 47 no 4 pp 351ndash354 2000

[12] C A Zarate Jr N E Brutsche L Ibrahim et al ldquoReplicationof Ketaminersquos antidepressant efficacy in bipolar depression arandomized controlled add-on trialrdquo Biological Psychiatry vol71 no 11 pp 939ndash946 2012

[13] W-L Zhu S-J Wang M-M Liu et al ldquoGlycine siteN-methyl-D-aspartate receptor antagonist7-CTKA producesrapid antidepressant-like effects in male ratsrdquo Journal of Psychi-atry amp Neuroscience vol 38 no 5 pp 306ndash316 2013

[14] S Akhondzadeh and S H Abbasi ldquoHerbal medicine inthe treatment of Alzhelmerrsquos diseaserdquo American Journal ofAlzheimerrsquos Disease and other Dementias vol 21 no 2 pp 113ndash118 2006

[15] D P Briskin ldquoMedicinal plants and phytomedicines Linkingplant biochemistry and physiology to human healthrdquo PlantPhysiology vol 124 no 2 pp 507ndash514 2000

[16] R M Darwish and T A Aburjai ldquoEffect of ethnomedicinalplants used in folklore medicine in Jordan as antibiotic resis-tant inhibitors on Escherichia colirdquo BMC Complementary andAlternative Medicine vol 10 article 9 2010

[17] NRC Guideforthe Careand Useof Laboratory Animals TheNational Academies Press 1996

[18] R D Porsolt M Le Pichon and M Jalfre ldquoDepression a newanimal model sensitive to antidepressant treatmentsrdquo Naturevol 266 no 5604 pp 730ndash732 1977

[19] L Steru R Chermat B Thierry and P Simon ldquoThe tailsuspension test a new method for screening antidepressants inmicerdquo Psychopharmacology vol 85 no 3 pp 367ndash370 1985

[20] O F OrsquoLeary A J Bechtholt J J Crowley T E Hill M EPage and I Lucki ldquoDepletion of serotonin and catecholaminesblock the acute behavioral response to different classes ofantidepressant drugs in the mouse tail suspension testrdquo Psy-chopharmacology vol 192 no 3 pp 357ndash371 2007

[21] P L M van Giersbergen E van Duinkerken C G J SweepV M Wiegant J M van Ree and W de Jong ldquo120572-Methyldopainduces a naltrexone-insensitive antinociception and hypo-motility in ratsrdquo British Journal of Pharmacology vol 99 no 3pp 467ndash472 1990

[22] J F Cryan M E Page and I Lucki ldquoDifferential behav-ioral effects of the antidepressants reboxetine fluoxetine andmoclobemide in a modified forced swim test following chronictreatmentrdquo Psychopharmacology vol 182 no 3 pp 335ndash3442005

[23] B Petit-Demouliere F Chenu and M Bourin ldquoForced swim-ming test in mice a review of antidepressant activityrdquo Psy-chopharmacology vol 177 no 3 pp 245ndash255 2005

[24] P L Delgado H L Miller R M Salomon et al ldquoTryptophan-depletion challenge in depressed patients treated withdesipramine or fluoxetine implications for the role of

12 ISRN Pharmacology

serotonin in the mechanism of antidepressant actionrdquoBiological Psychiatry vol 46 no 2 pp 212ndash220 1999

[25] A L Eckeli F Dach and A L S Rodrigues ldquoAcute treatmentswith GMP produce antidepressant-like effects in micerdquo Neu-roReport vol 11 no 9 pp 1839ndash1843 2000

[26] E C Gavioli CW Vaughan GMarzola et al ldquoAntidepressant-like effects of the nociceptinorphanin FQ receptor antago-nist UFP-101 new evidence from rats and micerdquo Naunyn-Schmiedebergrsquos Archives of Pharmacology vol 369 no 6 pp547ndash553 2004

[27] M E Page M J Detke A Dalvi L G Kirby and I LuckildquoSerotonergic mediation of the effects of fluoxetine but notdesipramine in the rat forced swimming testrdquo Psychopharma-cology vol 147 no 2 pp 162ndash167 1999

[28] M E Page and I Lucki ldquoEffects of acute and chronic reboxetinetreatment on stress-inducedmonoamine efflux in the rat frontalcortexrdquo Neuropsychopharmacology vol 27 no 2 pp 237ndash2472002

[29] F P Bymaster W Zhang P A Carter et al ldquoFluoxetinebut not other selective serotonin uptake inhibitors increasesnorepinephrine and dopamine extracellular levels in prefrontalcortexrdquo Psychopharmacology vol 160 no 4 pp 353ndash361 2002

[30] D T Chau P V Rada K Kim R A Kosloff and B G HoebelldquoFluoxetine alleviates behavioral depression while decreasingacetylcholine release in the nucleus accumbens shellrdquoNeuropsy-chopharmacology vol 36 no 8 pp 1729ndash1737 2011

[31] S J Corne R W Pickering and B T Warner ldquoA methodfor assessing the effects of drugs on the central actions of5-hydroxytryptaminerdquo British Journal of Pharmacology andChemotherapy vol 20 pp 106ndash120 1963

[32] S Schreiber and C G Pick ldquoFluoxetine for blepharospasminteraction of serotonin and dopaminerdquo Journal of Nervous andMental Disease vol 183 no 11 pp 719ndash721 1995

[33] W D Essman A Singh and I Lucki ldquoSerotonergic propertiesof cocaine effects on a 5-HT2 receptor-mediated behavior andon extracellular concentrations of serotonin and dopaminerdquoPharmacology Biochemistry and Behavior vol 49 no 1 pp 107ndash113 1994

[34] L-F Xu W-J Chu X-Y Qing et al ldquoProtopine inhibits sero-tonin transporter and noradrenaline transporter and has theantidepressant-like effect in mice modelsrdquoNeuropharmacologyvol 50 no 8 pp 934ndash940 2006

[35] GWDeMuth and SHAckerman ldquo120572-Methyldopa and depres-sion a clinical study and review of the literaturerdquo AmericanJournal of Psychiatry vol 140 no 5 pp 534ndash538 1983

[36] J Ji J L Mcdermott and D E Dluzen ldquoSex differences inK+-evoked striatal dopamine output from superfused striataltissue fragments of reserpine-treated CD-1 micerdquo Journal ofNeuroendocrinology vol 19 no 9 pp 725ndash731 2007

[37] R R Metzger J M Brown V Sandoval et al ldquoInhibitoryeffect of reserpine ondopamine transporter functionrdquoEuropeanJournal of Pharmacology vol 456 no 1ndash3 pp 39ndash43 2002

[38] M Fukui R M Rodriguiz J Zhou et al ldquoVmat2 heterozygousmutant mice display a depressive-like phenotyperdquo Journal ofNeuroscience vol 27 no 39 pp 10520ndash10529 2007

[39] E Woode E Boakye-Gyasi N Amidu C Ansah and MDuwiejua ldquoAnxiolytic and antidepressant effects of a leafextract ofPalisota hirsutaK Schum (Commelinaceae) inmicerdquoInternational Journal of Pharmacology vol 6 no 1 pp 1ndash172010

[40] E Poleszak P Wlaz B Szewczyk et al ldquoA complexinteraction between glycineNMDA receptors andserotonergicnoradrenergic antidepressants in the forcedswim test in micerdquo Journal of Neural Transmission vol 118 no11 pp 1535ndash1546 2011

[41] E Berrocoso K Ikeda I Sora et al ldquoActive behavioursproduced by antidepressants and opioids in the mouse tailsuspension testrdquoThe International Journal of Neuropsychophar-macology vol 61 no 1 pp 151ndash162 2012

[42] J F Cryan and I Lucki ldquoAntidepressant-like behavioral effectsmediated by 5-hydroxytryptamine(2C) receptorsrdquo Journal ofPharmacology andExperimentalTherapeutics vol 295 no 3 pp1120ndash1126 2000

Submit your manuscripts athttpwwwhindawicom

PainResearch and TreatmentHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom

Volume 2014

ToxinsJournal of

VaccinesJournal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

AntibioticsInternational Journal of

ToxicologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

StrokeResearch and TreatmentHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Drug DeliveryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in Pharmacological Sciences

Tropical MedicineJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

AddictionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

Emergency Medicine InternationalHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Autoimmune Diseases

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Anesthesiology Research and Practice

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Pharmaceutics

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MEDIATORSINFLAMMATION

of

10 ISRN Pharmacology

Imm

obili

ty ti

me (

s)

60

50

40

30

20

10

0

Ctrl MOE FLX DSP

lowastlowastlowastlowastlowastlowast

lowastlowastlowast

daggerdaggerdagger

daggerdaggerdaggerdaggerdaggerdagger

(a)

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

Imm

obili

ty ti

me (

s)

60

50

40

30

20

10

0

Ctrl MOE FLX DSP

daggerdagger

(b)

Swim

min

g tim

e (s)

80

60

40

20

0

Ctrl MOE FLX DSP

lowastlowastlowast lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

daggerdaggerdagger

(c)

Swim

min

g tim

e (s)

80

60

40

20

0

Ctrl MOE FLX DSP

lowastlowastlowast

lowastlowastlowast

lowastlowastlowast

lowastlowastlowastlowastlowastlowast

daggerdaggerdagger

daggerdagger

lowastlowast

(d)

Clim

bing

tim

e (s)

50

40

30

20

10

8

6

4

2

0

lowastlowast

UntreatedD-serine-treated

lowast

lowast

Ctrl MOE FLX DSP

(e)

Clim

bing

tim

e (s)

50

40

30

20

10

8

6

4

2

0

lowastlowastlowastlowastlowastlowast

UntreatedD-cycloserine-treated

lowast

lowast

dagger

Ctrl MOE FLX DSP

(f)

Figure 7 Effects of d-serine (DS) or d-cycloserine (DCS) pretreatment on (a b) mean immobility count (c d) swimming count and (ef) climbing count of extract MOE (100mg kgminus1) fluoxetine FLX (10mg kgminus1) and desipramine DSP (10mg kgminus1) treatment in the forcedswimming test (FST) Data are presented as means plusmn SEM significantly different from control lowastlowast119875 lt 001 lowastlowastlowast119875 lt 0001 by Newman Keulrsquostest Significant difference between treatments dagger119875 lt 005 daggerdagger119875 lt 001 and daggerdaggerdagger119875 lt 0001

ISRN Pharmacology 11

with opioid receptors when combined with DCS In the FSTMOE and FLX unlike DSP increased swimming behaviourwhich is sensitive to selective serotonin reuptake inhibitors(SSRIs) and 5HT agonists [22 42] This behavior exhibitedbyMOE and fluoxetine-treated mice was inhibited by DS butincreased byDCS pretreatment further supporting the theorythat antidepressant effect of serotonin based drugs dependson the inhibition of the glycineNMDA receptor complexand the enhancement of antidepressant activity dependson the serotoninergic pathway [40] Climbing scores weredecreased by both MOE and FLX and this was not affectedby both DS and DCS pretreatment This confirms theirlack of noradrenergic activity DSP a selective noradrenergicreuptake inhibitor on the contrary increased climbing scorewhich was unaffected by DCS pretreatment but decreasedby DS It is worth mentioning that the extract fluoxetinedesipramine alone or their combination with either d-serineor d-cycloserine did not impair motor coordination Thusthe behavioural effect observed can be attributed to drugtreatment alone

5 Conclusion

The present study shows that Mallotus oppositifolius hasantidepressant-like effect in mice and this may be mediatedvia enhancement of serotoninergic neurotransmission andinhibition of glycineNMDA receptor complex activationThe antidepressant effect of the extract may be devoid ofnoradrenergic mechanisms

Conflict of Interests

The authors declare that they have no conflict of interests

References

[1] P V Holmes ldquoRodent models of depression reexaminingvalidity without anthropomorphic inferencerdquo Critical Reviewsin Neurobiology vol 15 no 2 pp 143ndash174 2003

[2] J Alonso M C Angermeyer S Bernert et al ldquoPrevalence ofmental disorders in Europe results from the European Study ofthe Epidemiology ofMental Disorders (ESEMeD) projectrdquoActaPsychiatrica Scandinavica Supplement vol 109 no 420 pp 21ndash27 2004

[3] T B Ustun J L Ayuso-Mateos S Chatterji C Mathers and CJ L Murray ldquoGlobal burden of depressive disorders in the year2000rdquo British Journal of Psychiatry vol 184 pp 386ndash392 2004

[4] H Gilmour and S B Patten ldquoDepression and work impair-mentrdquo Health Reports vol 18 no 1 pp 9ndash22 2007

[5] E Poleszak B Szewczyk E Kedzierska P Wlaz A Pilcand G Nowak ldquoAntidepressant- and anxiolytic-like activity ofmagnesium in micerdquo Pharmacology Biochemistry and Behaviorvol 78 no 1 pp 7ndash12 2004

[6] P Skolnick P Popik and R Trullas ldquoGlutamate-based antide-pressants 20 years onrdquo Trends in Pharmacological Sciences vol30 no 11 pp 563ndash569 2009

[7] J F Cryan A Markou and I Lucki ldquoAssessing antidepressantactivity in rodents recent developments and future needsrdquoTrends in Pharmacological Sciences vol 23 no 5 pp 238ndash2452002

[8] E J Nestler M Barrot R J DiLeone A J Eisch S J Gold andLMMonteggia ldquoNeurobiology of depressionrdquoNeuron vol 34no 1 pp 13ndash25 2002

[9] R Trullas and P Skolnick ldquoFunctional antagonists at theNMDA receptor complex exhibit antidepressant actionsrdquo Euro-pean Journal of Pharmacology vol 185 no 1 pp 1ndash10 1990

[10] M Siwek D Dudek I A Paul et al ldquoZinc supplementationaugments efficacy of imipramine in treatment resistant patientsa double blind placebo-controlled studyrdquo Journal of AffectiveDisorders vol 118 no 1ndash3 pp 187ndash195 2009

[11] R M Berman A Cappiello A Anand et al ldquoAntidepressanteffects of ketamine in depressed patientsrdquo Biological Psychiatryvol 47 no 4 pp 351ndash354 2000

[12] C A Zarate Jr N E Brutsche L Ibrahim et al ldquoReplicationof Ketaminersquos antidepressant efficacy in bipolar depression arandomized controlled add-on trialrdquo Biological Psychiatry vol71 no 11 pp 939ndash946 2012

[13] W-L Zhu S-J Wang M-M Liu et al ldquoGlycine siteN-methyl-D-aspartate receptor antagonist7-CTKA producesrapid antidepressant-like effects in male ratsrdquo Journal of Psychi-atry amp Neuroscience vol 38 no 5 pp 306ndash316 2013

[14] S Akhondzadeh and S H Abbasi ldquoHerbal medicine inthe treatment of Alzhelmerrsquos diseaserdquo American Journal ofAlzheimerrsquos Disease and other Dementias vol 21 no 2 pp 113ndash118 2006

[15] D P Briskin ldquoMedicinal plants and phytomedicines Linkingplant biochemistry and physiology to human healthrdquo PlantPhysiology vol 124 no 2 pp 507ndash514 2000

[16] R M Darwish and T A Aburjai ldquoEffect of ethnomedicinalplants used in folklore medicine in Jordan as antibiotic resis-tant inhibitors on Escherichia colirdquo BMC Complementary andAlternative Medicine vol 10 article 9 2010

[17] NRC Guideforthe Careand Useof Laboratory Animals TheNational Academies Press 1996

[18] R D Porsolt M Le Pichon and M Jalfre ldquoDepression a newanimal model sensitive to antidepressant treatmentsrdquo Naturevol 266 no 5604 pp 730ndash732 1977

[19] L Steru R Chermat B Thierry and P Simon ldquoThe tailsuspension test a new method for screening antidepressants inmicerdquo Psychopharmacology vol 85 no 3 pp 367ndash370 1985

[20] O F OrsquoLeary A J Bechtholt J J Crowley T E Hill M EPage and I Lucki ldquoDepletion of serotonin and catecholaminesblock the acute behavioral response to different classes ofantidepressant drugs in the mouse tail suspension testrdquo Psy-chopharmacology vol 192 no 3 pp 357ndash371 2007

[21] P L M van Giersbergen E van Duinkerken C G J SweepV M Wiegant J M van Ree and W de Jong ldquo120572-Methyldopainduces a naltrexone-insensitive antinociception and hypo-motility in ratsrdquo British Journal of Pharmacology vol 99 no 3pp 467ndash472 1990

[22] J F Cryan M E Page and I Lucki ldquoDifferential behav-ioral effects of the antidepressants reboxetine fluoxetine andmoclobemide in a modified forced swim test following chronictreatmentrdquo Psychopharmacology vol 182 no 3 pp 335ndash3442005

[23] B Petit-Demouliere F Chenu and M Bourin ldquoForced swim-ming test in mice a review of antidepressant activityrdquo Psy-chopharmacology vol 177 no 3 pp 245ndash255 2005

[24] P L Delgado H L Miller R M Salomon et al ldquoTryptophan-depletion challenge in depressed patients treated withdesipramine or fluoxetine implications for the role of

12 ISRN Pharmacology

serotonin in the mechanism of antidepressant actionrdquoBiological Psychiatry vol 46 no 2 pp 212ndash220 1999

[25] A L Eckeli F Dach and A L S Rodrigues ldquoAcute treatmentswith GMP produce antidepressant-like effects in micerdquo Neu-roReport vol 11 no 9 pp 1839ndash1843 2000

[26] E C Gavioli CW Vaughan GMarzola et al ldquoAntidepressant-like effects of the nociceptinorphanin FQ receptor antago-nist UFP-101 new evidence from rats and micerdquo Naunyn-Schmiedebergrsquos Archives of Pharmacology vol 369 no 6 pp547ndash553 2004

[27] M E Page M J Detke A Dalvi L G Kirby and I LuckildquoSerotonergic mediation of the effects of fluoxetine but notdesipramine in the rat forced swimming testrdquo Psychopharma-cology vol 147 no 2 pp 162ndash167 1999

[28] M E Page and I Lucki ldquoEffects of acute and chronic reboxetinetreatment on stress-inducedmonoamine efflux in the rat frontalcortexrdquo Neuropsychopharmacology vol 27 no 2 pp 237ndash2472002

[29] F P Bymaster W Zhang P A Carter et al ldquoFluoxetinebut not other selective serotonin uptake inhibitors increasesnorepinephrine and dopamine extracellular levels in prefrontalcortexrdquo Psychopharmacology vol 160 no 4 pp 353ndash361 2002

[30] D T Chau P V Rada K Kim R A Kosloff and B G HoebelldquoFluoxetine alleviates behavioral depression while decreasingacetylcholine release in the nucleus accumbens shellrdquoNeuropsy-chopharmacology vol 36 no 8 pp 1729ndash1737 2011

[31] S J Corne R W Pickering and B T Warner ldquoA methodfor assessing the effects of drugs on the central actions of5-hydroxytryptaminerdquo British Journal of Pharmacology andChemotherapy vol 20 pp 106ndash120 1963

[32] S Schreiber and C G Pick ldquoFluoxetine for blepharospasminteraction of serotonin and dopaminerdquo Journal of Nervous andMental Disease vol 183 no 11 pp 719ndash721 1995

[33] W D Essman A Singh and I Lucki ldquoSerotonergic propertiesof cocaine effects on a 5-HT2 receptor-mediated behavior andon extracellular concentrations of serotonin and dopaminerdquoPharmacology Biochemistry and Behavior vol 49 no 1 pp 107ndash113 1994

[34] L-F Xu W-J Chu X-Y Qing et al ldquoProtopine inhibits sero-tonin transporter and noradrenaline transporter and has theantidepressant-like effect in mice modelsrdquoNeuropharmacologyvol 50 no 8 pp 934ndash940 2006

[35] GWDeMuth and SHAckerman ldquo120572-Methyldopa and depres-sion a clinical study and review of the literaturerdquo AmericanJournal of Psychiatry vol 140 no 5 pp 534ndash538 1983

[36] J Ji J L Mcdermott and D E Dluzen ldquoSex differences inK+-evoked striatal dopamine output from superfused striataltissue fragments of reserpine-treated CD-1 micerdquo Journal ofNeuroendocrinology vol 19 no 9 pp 725ndash731 2007

[37] R R Metzger J M Brown V Sandoval et al ldquoInhibitoryeffect of reserpine ondopamine transporter functionrdquoEuropeanJournal of Pharmacology vol 456 no 1ndash3 pp 39ndash43 2002

[38] M Fukui R M Rodriguiz J Zhou et al ldquoVmat2 heterozygousmutant mice display a depressive-like phenotyperdquo Journal ofNeuroscience vol 27 no 39 pp 10520ndash10529 2007

[39] E Woode E Boakye-Gyasi N Amidu C Ansah and MDuwiejua ldquoAnxiolytic and antidepressant effects of a leafextract ofPalisota hirsutaK Schum (Commelinaceae) inmicerdquoInternational Journal of Pharmacology vol 6 no 1 pp 1ndash172010

[40] E Poleszak P Wlaz B Szewczyk et al ldquoA complexinteraction between glycineNMDA receptors andserotonergicnoradrenergic antidepressants in the forcedswim test in micerdquo Journal of Neural Transmission vol 118 no11 pp 1535ndash1546 2011

[41] E Berrocoso K Ikeda I Sora et al ldquoActive behavioursproduced by antidepressants and opioids in the mouse tailsuspension testrdquoThe International Journal of Neuropsychophar-macology vol 61 no 1 pp 151ndash162 2012

[42] J F Cryan and I Lucki ldquoAntidepressant-like behavioral effectsmediated by 5-hydroxytryptamine(2C) receptorsrdquo Journal ofPharmacology andExperimentalTherapeutics vol 295 no 3 pp1120ndash1126 2000

Submit your manuscripts athttpwwwhindawicom

PainResearch and TreatmentHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom

Volume 2014

ToxinsJournal of

VaccinesJournal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

AntibioticsInternational Journal of

ToxicologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

StrokeResearch and TreatmentHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Drug DeliveryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in Pharmacological Sciences

Tropical MedicineJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

AddictionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

Emergency Medicine InternationalHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Autoimmune Diseases

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Anesthesiology Research and Practice

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Pharmaceutics

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MEDIATORSINFLAMMATION

of

ISRN Pharmacology 11

with opioid receptors when combined with DCS In the FSTMOE and FLX unlike DSP increased swimming behaviourwhich is sensitive to selective serotonin reuptake inhibitors(SSRIs) and 5HT agonists [22 42] This behavior exhibitedbyMOE and fluoxetine-treated mice was inhibited by DS butincreased byDCS pretreatment further supporting the theorythat antidepressant effect of serotonin based drugs dependson the inhibition of the glycineNMDA receptor complexand the enhancement of antidepressant activity dependson the serotoninergic pathway [40] Climbing scores weredecreased by both MOE and FLX and this was not affectedby both DS and DCS pretreatment This confirms theirlack of noradrenergic activity DSP a selective noradrenergicreuptake inhibitor on the contrary increased climbing scorewhich was unaffected by DCS pretreatment but decreasedby DS It is worth mentioning that the extract fluoxetinedesipramine alone or their combination with either d-serineor d-cycloserine did not impair motor coordination Thusthe behavioural effect observed can be attributed to drugtreatment alone

5 Conclusion

The present study shows that Mallotus oppositifolius hasantidepressant-like effect in mice and this may be mediatedvia enhancement of serotoninergic neurotransmission andinhibition of glycineNMDA receptor complex activationThe antidepressant effect of the extract may be devoid ofnoradrenergic mechanisms

Conflict of Interests

The authors declare that they have no conflict of interests

References

[1] P V Holmes ldquoRodent models of depression reexaminingvalidity without anthropomorphic inferencerdquo Critical Reviewsin Neurobiology vol 15 no 2 pp 143ndash174 2003

[2] J Alonso M C Angermeyer S Bernert et al ldquoPrevalence ofmental disorders in Europe results from the European Study ofthe Epidemiology ofMental Disorders (ESEMeD) projectrdquoActaPsychiatrica Scandinavica Supplement vol 109 no 420 pp 21ndash27 2004

[3] T B Ustun J L Ayuso-Mateos S Chatterji C Mathers and CJ L Murray ldquoGlobal burden of depressive disorders in the year2000rdquo British Journal of Psychiatry vol 184 pp 386ndash392 2004

[4] H Gilmour and S B Patten ldquoDepression and work impair-mentrdquo Health Reports vol 18 no 1 pp 9ndash22 2007

[5] E Poleszak B Szewczyk E Kedzierska P Wlaz A Pilcand G Nowak ldquoAntidepressant- and anxiolytic-like activity ofmagnesium in micerdquo Pharmacology Biochemistry and Behaviorvol 78 no 1 pp 7ndash12 2004

[6] P Skolnick P Popik and R Trullas ldquoGlutamate-based antide-pressants 20 years onrdquo Trends in Pharmacological Sciences vol30 no 11 pp 563ndash569 2009

[7] J F Cryan A Markou and I Lucki ldquoAssessing antidepressantactivity in rodents recent developments and future needsrdquoTrends in Pharmacological Sciences vol 23 no 5 pp 238ndash2452002

[8] E J Nestler M Barrot R J DiLeone A J Eisch S J Gold andLMMonteggia ldquoNeurobiology of depressionrdquoNeuron vol 34no 1 pp 13ndash25 2002

[9] R Trullas and P Skolnick ldquoFunctional antagonists at theNMDA receptor complex exhibit antidepressant actionsrdquo Euro-pean Journal of Pharmacology vol 185 no 1 pp 1ndash10 1990

[10] M Siwek D Dudek I A Paul et al ldquoZinc supplementationaugments efficacy of imipramine in treatment resistant patientsa double blind placebo-controlled studyrdquo Journal of AffectiveDisorders vol 118 no 1ndash3 pp 187ndash195 2009

[11] R M Berman A Cappiello A Anand et al ldquoAntidepressanteffects of ketamine in depressed patientsrdquo Biological Psychiatryvol 47 no 4 pp 351ndash354 2000

[12] C A Zarate Jr N E Brutsche L Ibrahim et al ldquoReplicationof Ketaminersquos antidepressant efficacy in bipolar depression arandomized controlled add-on trialrdquo Biological Psychiatry vol71 no 11 pp 939ndash946 2012

[13] W-L Zhu S-J Wang M-M Liu et al ldquoGlycine siteN-methyl-D-aspartate receptor antagonist7-CTKA producesrapid antidepressant-like effects in male ratsrdquo Journal of Psychi-atry amp Neuroscience vol 38 no 5 pp 306ndash316 2013

[14] S Akhondzadeh and S H Abbasi ldquoHerbal medicine inthe treatment of Alzhelmerrsquos diseaserdquo American Journal ofAlzheimerrsquos Disease and other Dementias vol 21 no 2 pp 113ndash118 2006

[15] D P Briskin ldquoMedicinal plants and phytomedicines Linkingplant biochemistry and physiology to human healthrdquo PlantPhysiology vol 124 no 2 pp 507ndash514 2000

[16] R M Darwish and T A Aburjai ldquoEffect of ethnomedicinalplants used in folklore medicine in Jordan as antibiotic resis-tant inhibitors on Escherichia colirdquo BMC Complementary andAlternative Medicine vol 10 article 9 2010

[17] NRC Guideforthe Careand Useof Laboratory Animals TheNational Academies Press 1996

[18] R D Porsolt M Le Pichon and M Jalfre ldquoDepression a newanimal model sensitive to antidepressant treatmentsrdquo Naturevol 266 no 5604 pp 730ndash732 1977

[19] L Steru R Chermat B Thierry and P Simon ldquoThe tailsuspension test a new method for screening antidepressants inmicerdquo Psychopharmacology vol 85 no 3 pp 367ndash370 1985

[20] O F OrsquoLeary A J Bechtholt J J Crowley T E Hill M EPage and I Lucki ldquoDepletion of serotonin and catecholaminesblock the acute behavioral response to different classes ofantidepressant drugs in the mouse tail suspension testrdquo Psy-chopharmacology vol 192 no 3 pp 357ndash371 2007

[21] P L M van Giersbergen E van Duinkerken C G J SweepV M Wiegant J M van Ree and W de Jong ldquo120572-Methyldopainduces a naltrexone-insensitive antinociception and hypo-motility in ratsrdquo British Journal of Pharmacology vol 99 no 3pp 467ndash472 1990

[22] J F Cryan M E Page and I Lucki ldquoDifferential behav-ioral effects of the antidepressants reboxetine fluoxetine andmoclobemide in a modified forced swim test following chronictreatmentrdquo Psychopharmacology vol 182 no 3 pp 335ndash3442005

[23] B Petit-Demouliere F Chenu and M Bourin ldquoForced swim-ming test in mice a review of antidepressant activityrdquo Psy-chopharmacology vol 177 no 3 pp 245ndash255 2005

[24] P L Delgado H L Miller R M Salomon et al ldquoTryptophan-depletion challenge in depressed patients treated withdesipramine or fluoxetine implications for the role of

12 ISRN Pharmacology

serotonin in the mechanism of antidepressant actionrdquoBiological Psychiatry vol 46 no 2 pp 212ndash220 1999

[25] A L Eckeli F Dach and A L S Rodrigues ldquoAcute treatmentswith GMP produce antidepressant-like effects in micerdquo Neu-roReport vol 11 no 9 pp 1839ndash1843 2000

[26] E C Gavioli CW Vaughan GMarzola et al ldquoAntidepressant-like effects of the nociceptinorphanin FQ receptor antago-nist UFP-101 new evidence from rats and micerdquo Naunyn-Schmiedebergrsquos Archives of Pharmacology vol 369 no 6 pp547ndash553 2004

[27] M E Page M J Detke A Dalvi L G Kirby and I LuckildquoSerotonergic mediation of the effects of fluoxetine but notdesipramine in the rat forced swimming testrdquo Psychopharma-cology vol 147 no 2 pp 162ndash167 1999

[28] M E Page and I Lucki ldquoEffects of acute and chronic reboxetinetreatment on stress-inducedmonoamine efflux in the rat frontalcortexrdquo Neuropsychopharmacology vol 27 no 2 pp 237ndash2472002

[29] F P Bymaster W Zhang P A Carter et al ldquoFluoxetinebut not other selective serotonin uptake inhibitors increasesnorepinephrine and dopamine extracellular levels in prefrontalcortexrdquo Psychopharmacology vol 160 no 4 pp 353ndash361 2002

[30] D T Chau P V Rada K Kim R A Kosloff and B G HoebelldquoFluoxetine alleviates behavioral depression while decreasingacetylcholine release in the nucleus accumbens shellrdquoNeuropsy-chopharmacology vol 36 no 8 pp 1729ndash1737 2011

[31] S J Corne R W Pickering and B T Warner ldquoA methodfor assessing the effects of drugs on the central actions of5-hydroxytryptaminerdquo British Journal of Pharmacology andChemotherapy vol 20 pp 106ndash120 1963

[32] S Schreiber and C G Pick ldquoFluoxetine for blepharospasminteraction of serotonin and dopaminerdquo Journal of Nervous andMental Disease vol 183 no 11 pp 719ndash721 1995

[33] W D Essman A Singh and I Lucki ldquoSerotonergic propertiesof cocaine effects on a 5-HT2 receptor-mediated behavior andon extracellular concentrations of serotonin and dopaminerdquoPharmacology Biochemistry and Behavior vol 49 no 1 pp 107ndash113 1994

[34] L-F Xu W-J Chu X-Y Qing et al ldquoProtopine inhibits sero-tonin transporter and noradrenaline transporter and has theantidepressant-like effect in mice modelsrdquoNeuropharmacologyvol 50 no 8 pp 934ndash940 2006

[35] GWDeMuth and SHAckerman ldquo120572-Methyldopa and depres-sion a clinical study and review of the literaturerdquo AmericanJournal of Psychiatry vol 140 no 5 pp 534ndash538 1983

[36] J Ji J L Mcdermott and D E Dluzen ldquoSex differences inK+-evoked striatal dopamine output from superfused striataltissue fragments of reserpine-treated CD-1 micerdquo Journal ofNeuroendocrinology vol 19 no 9 pp 725ndash731 2007

[37] R R Metzger J M Brown V Sandoval et al ldquoInhibitoryeffect of reserpine ondopamine transporter functionrdquoEuropeanJournal of Pharmacology vol 456 no 1ndash3 pp 39ndash43 2002

[38] M Fukui R M Rodriguiz J Zhou et al ldquoVmat2 heterozygousmutant mice display a depressive-like phenotyperdquo Journal ofNeuroscience vol 27 no 39 pp 10520ndash10529 2007

[39] E Woode E Boakye-Gyasi N Amidu C Ansah and MDuwiejua ldquoAnxiolytic and antidepressant effects of a leafextract ofPalisota hirsutaK Schum (Commelinaceae) inmicerdquoInternational Journal of Pharmacology vol 6 no 1 pp 1ndash172010

[40] E Poleszak P Wlaz B Szewczyk et al ldquoA complexinteraction between glycineNMDA receptors andserotonergicnoradrenergic antidepressants in the forcedswim test in micerdquo Journal of Neural Transmission vol 118 no11 pp 1535ndash1546 2011

[41] E Berrocoso K Ikeda I Sora et al ldquoActive behavioursproduced by antidepressants and opioids in the mouse tailsuspension testrdquoThe International Journal of Neuropsychophar-macology vol 61 no 1 pp 151ndash162 2012

[42] J F Cryan and I Lucki ldquoAntidepressant-like behavioral effectsmediated by 5-hydroxytryptamine(2C) receptorsrdquo Journal ofPharmacology andExperimentalTherapeutics vol 295 no 3 pp1120ndash1126 2000

Submit your manuscripts athttpwwwhindawicom

PainResearch and TreatmentHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom

Volume 2014

ToxinsJournal of

VaccinesJournal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

AntibioticsInternational Journal of

ToxicologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

StrokeResearch and TreatmentHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Drug DeliveryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in Pharmacological Sciences

Tropical MedicineJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

AddictionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

Emergency Medicine InternationalHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Autoimmune Diseases

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Anesthesiology Research and Practice

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Pharmaceutics

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MEDIATORSINFLAMMATION

of

12 ISRN Pharmacology

serotonin in the mechanism of antidepressant actionrdquoBiological Psychiatry vol 46 no 2 pp 212ndash220 1999

[25] A L Eckeli F Dach and A L S Rodrigues ldquoAcute treatmentswith GMP produce antidepressant-like effects in micerdquo Neu-roReport vol 11 no 9 pp 1839ndash1843 2000

[26] E C Gavioli CW Vaughan GMarzola et al ldquoAntidepressant-like effects of the nociceptinorphanin FQ receptor antago-nist UFP-101 new evidence from rats and micerdquo Naunyn-Schmiedebergrsquos Archives of Pharmacology vol 369 no 6 pp547ndash553 2004

[27] M E Page M J Detke A Dalvi L G Kirby and I LuckildquoSerotonergic mediation of the effects of fluoxetine but notdesipramine in the rat forced swimming testrdquo Psychopharma-cology vol 147 no 2 pp 162ndash167 1999

[28] M E Page and I Lucki ldquoEffects of acute and chronic reboxetinetreatment on stress-inducedmonoamine efflux in the rat frontalcortexrdquo Neuropsychopharmacology vol 27 no 2 pp 237ndash2472002

[29] F P Bymaster W Zhang P A Carter et al ldquoFluoxetinebut not other selective serotonin uptake inhibitors increasesnorepinephrine and dopamine extracellular levels in prefrontalcortexrdquo Psychopharmacology vol 160 no 4 pp 353ndash361 2002

[30] D T Chau P V Rada K Kim R A Kosloff and B G HoebelldquoFluoxetine alleviates behavioral depression while decreasingacetylcholine release in the nucleus accumbens shellrdquoNeuropsy-chopharmacology vol 36 no 8 pp 1729ndash1737 2011

[31] S J Corne R W Pickering and B T Warner ldquoA methodfor assessing the effects of drugs on the central actions of5-hydroxytryptaminerdquo British Journal of Pharmacology andChemotherapy vol 20 pp 106ndash120 1963

[32] S Schreiber and C G Pick ldquoFluoxetine for blepharospasminteraction of serotonin and dopaminerdquo Journal of Nervous andMental Disease vol 183 no 11 pp 719ndash721 1995

[33] W D Essman A Singh and I Lucki ldquoSerotonergic propertiesof cocaine effects on a 5-HT2 receptor-mediated behavior andon extracellular concentrations of serotonin and dopaminerdquoPharmacology Biochemistry and Behavior vol 49 no 1 pp 107ndash113 1994

[34] L-F Xu W-J Chu X-Y Qing et al ldquoProtopine inhibits sero-tonin transporter and noradrenaline transporter and has theantidepressant-like effect in mice modelsrdquoNeuropharmacologyvol 50 no 8 pp 934ndash940 2006

[35] GWDeMuth and SHAckerman ldquo120572-Methyldopa and depres-sion a clinical study and review of the literaturerdquo AmericanJournal of Psychiatry vol 140 no 5 pp 534ndash538 1983

[36] J Ji J L Mcdermott and D E Dluzen ldquoSex differences inK+-evoked striatal dopamine output from superfused striataltissue fragments of reserpine-treated CD-1 micerdquo Journal ofNeuroendocrinology vol 19 no 9 pp 725ndash731 2007

[37] R R Metzger J M Brown V Sandoval et al ldquoInhibitoryeffect of reserpine ondopamine transporter functionrdquoEuropeanJournal of Pharmacology vol 456 no 1ndash3 pp 39ndash43 2002

[38] M Fukui R M Rodriguiz J Zhou et al ldquoVmat2 heterozygousmutant mice display a depressive-like phenotyperdquo Journal ofNeuroscience vol 27 no 39 pp 10520ndash10529 2007

[39] E Woode E Boakye-Gyasi N Amidu C Ansah and MDuwiejua ldquoAnxiolytic and antidepressant effects of a leafextract ofPalisota hirsutaK Schum (Commelinaceae) inmicerdquoInternational Journal of Pharmacology vol 6 no 1 pp 1ndash172010

[40] E Poleszak P Wlaz B Szewczyk et al ldquoA complexinteraction between glycineNMDA receptors andserotonergicnoradrenergic antidepressants in the forcedswim test in micerdquo Journal of Neural Transmission vol 118 no11 pp 1535ndash1546 2011

[41] E Berrocoso K Ikeda I Sora et al ldquoActive behavioursproduced by antidepressants and opioids in the mouse tailsuspension testrdquoThe International Journal of Neuropsychophar-macology vol 61 no 1 pp 151ndash162 2012

[42] J F Cryan and I Lucki ldquoAntidepressant-like behavioral effectsmediated by 5-hydroxytryptamine(2C) receptorsrdquo Journal ofPharmacology andExperimentalTherapeutics vol 295 no 3 pp1120ndash1126 2000

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PainResearch and TreatmentHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom

Volume 2014

ToxinsJournal of

VaccinesJournal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

AntibioticsInternational Journal of

ToxicologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

StrokeResearch and TreatmentHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Drug DeliveryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in Pharmacological Sciences

Tropical MedicineJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

AddictionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

Emergency Medicine InternationalHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Autoimmune Diseases

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Anesthesiology Research and Practice

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Pharmaceutics

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MEDIATORSINFLAMMATION

of

Submit your manuscripts athttpwwwhindawicom

PainResearch and TreatmentHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom

Volume 2014

ToxinsJournal of

VaccinesJournal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

AntibioticsInternational Journal of

ToxicologyJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

StrokeResearch and TreatmentHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Drug DeliveryJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Advances in Pharmacological Sciences

Tropical MedicineJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

AddictionJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

BioMed Research International

Emergency Medicine InternationalHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Autoimmune Diseases

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Anesthesiology Research and Practice

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Pharmaceutics

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

MEDIATORSINFLAMMATION

of