View
440
Download
1
Category
Preview:
DESCRIPTION
Citation preview
es-cle.miculartion). Ite ofthessicular
ofvity
inity,ismasics of
ofellsthe
has
ight
died
e a-
ular
om
at a
rane
tial
ease
in a
er L.
and
ese
ved.
G Model
NEUTOX-899; No of Pages 6
Brief communication
Synaptic effects of low molecular weight components from Chilean BlackWidow spider venom
Jorge Parodi *, Fernando Romero
Laboratorio de Neurociencia-CEBIOR, Departamento de Ciencia Preclinicas, Facultad de Medicina, Universidad de la Frontera, Montevideo 0870, Temuco, Chile
1. Introduction
The Chilean spider Latrodectus mactans pertains to the genusLatrodectus which is found worldwide (Garb et al., 2004) and isknown as the ‘‘Wheat Spider’’ or ‘‘Black Widow’’ and inhabitsvarious regions of Chile. The bite from this spider in humansproduces a systemic effect called latrodectism or systemiclatrodectism and in some cases results in death (Schenone andCorrea, 1985).
Venom collected from Chilean L. mactans in the VIII and IX regionsof Chile was shown to induce a sustained tonic effect in cardiac andsmooth muscle (Romero et al., 2003). In smooth muscle, themechanism of contraction is related to the permeability of Na+ andCa2+ ions which modulate the contractile response (Nouailhetaset al., 1985) that has a fast, phasic component followed by a slowermore sustained tonic component (Shimuta et al., 1982). Our studiesin the deferent vessel of the rat revealed that the effect inducedby the L. mactans venom is partially dependent of adrenergic and
cholinergic mediators (patent pending). These results raise qutions about the mechanism of action of the toxin on smooth musWe postulated ionic mechanism, to explain same of these systeeffects, based in the idea of described effects of low-moleccomponent from Black Widow venom, over muscle and alterathe cellular physiology (Kiyatkin et al., 1992; Grishin et al., 1993has been postulated that potassium currents, for the importancthese currents in the regulation of muscle contraction andparticipation over calcium homeostatic (Sanborn, 2000). A clasynaptic model was affects for a-latrotoxin and high-molecweight peptides (Auger and Marty, 2000) and dependentpotassium channels for normal regulation of synaptic acti(Pan and Stringer, 1997). We tested the effect of Chilean venomhippocampal neuron, and reported the changes in synaptic activfor have synaptic effects under control and postulate, mechanover neuromuscular union. For another way, we choice a bmodel of cell lines, for observation of passive electric propertiemembrane and not showed receptor or increased numberchannels (Varghese et al., 2006). For these reason used HEK 293 cfor the observation of changes in membranes conductance. In
NeuroToxicology xxx (2008) xxx–xxx
A R T I C L E I N F O
Article history:
Received 23 May 2008
Accepted 27 August 2008
Available online xxx
Keywords:
Synapses
Venom
Spider
Toxic
Black Widow
A B S T R A C T
a-Latrotoxin is the principal component of the venom from the euroasiatic Black Widow spider and
been studied for its pharmacological use as a synaptic modulator. Interestingly, smaller molecular we
fractions have been found to be associated with this toxin, but their cellular actions have not been stu
in detail. The venom from the Chilean Black Widow spider (Latrodectus mactans) does not produc
latrotoxin, however it does contain several small polypeptides. We have recently demonstrated cell
effects of these peptides at the synaptic level using whole-cell patch clamp techniques. Purified ven
from the glands of L. mactans was studied in 12 DIV rat hippocampal neuronal cultures. Venom
concentration of 10 nM was able to decrease neuronal conductance thereby increasing memb
resistance. This effect on the passive properties of the neurons induced a change in action poten
kinetics simulating the action of classic potassium channel blockers. These changes produced an incr
in spontaneous synaptic activity in rat hippocampal cultures in the presence of the venom
concentration- and time-dependent manner. These results indicate that venom from Chilean spid
mactans is capable of increasing cell membrane resistance, prolonging the action potential
generating an increase in synaptic activity demonstrating an interesting pharmacological effect of th
low molecular weight fragments.
� 2008 Elsevier Inc. All rights reser
Contents lists available at ScienceDirect
NeuroToxicology
iumof L.
ium
* Corresponding author at: Laboratorio de Neurociencia-CEBIOR, Facultad de
Medicina, Universidad de la Frontera, Montevideo 0870, Temuco, Chile.
Tel.: +56 45 734041.
E-mail address: jparodi@ufro.cl (J. Parodi).
Please cite this article in press as: Parodi J, Romero F. Synaptic effecspider venom, Neurotoxicology (2008), doi:10.1016/j.neuro.2008.0
0161-813X/$ – see front matter � 2008 Elsevier Inc. All rights reserved.
doi:10.1016/j.neuro.2008.08.006
present study was to analyze the possible participation of potassconductance on the systemic effects observed with the venommactans, recording cellular effects associated a changes in potassconductance in neurons and cells lines.
ts of low molecular weight components from Chilean Black Widow8.006
2. M
2.1.
Fdurifromas p(Romindiordethe
2.2.
Ttran0.1 Mwersecttubehom1000aliquprottech
2.3.
Tguidpregeuthremsolucallyneur35 mwerthey80%waspharexpe
2.4.
HD-MInc.)Inc.)ogiemed
2.5.
TsoluMgCcontGTP30 mneurtech(Axo
2
G Model
NEUTOX-899; No of Pages 6
Plesp
aterials and methods
Spider retrieval
emale adult L. mactans spiders from Chile were capturedng the summer months (December 2005 and January 2006)
the area of Alto Bio in the VIII region (7281605100W, 784502400S)reviously described, taking care not to damage breeding zones
ero et al., 2003). The specimens were maintained separate invidual jars for 30 days without food and given only water inr to stimulate the production and concentration of venom inglands.
Venom retrieval
he spiders were immersed in liquid nitrogen and after 1 minsferred to a phosphate saline buffer solution (PBS: NaH2PO4
, Na2HPO4 0.01 M, NaCl 1.35 M, pH 7.4) at 4 8C. The glandse removed and the membrane that binds them to the base wasioned. Each glands with its poison secreting, was placed into a
containing PBS (25 pairs of glands for 100 ml of PBS) andogenized. The homogenate was immediately centrifuged at� g for 15 min and the supernatant was subsequentlyoted, labeled total venom (TV) and frozen at �20 8C. The
ein content of the TV was measured using the Bradfordnique, with small modifications (BioRad Protein Assay).
Neuronal cultures
he animals were treated and handled according to NIHelines (National Institute of Health, USA). Timed (18 days)nant Sprague–Dawley rats were anaesthetized with ether andanized by cervical dislocation. The embryos were quickly
oved, decapitated and the brains placed in cold Hank’stion. Subsequently, the hippocampi were dissected; mechani-
dissociated using trypsin, collagenase and DNase III and theons were then plated at a density of 350,000 cells/ml ontom culture plates containing a monolayer of glia cells. Neurons
e maintained in culture for 12 days in vitro (DIV) at which pointwere used for experiments. The culture media consisted of
MEM, 2 mM glutamine, and 10% fetal bovine serum. The mediareplaced with fresh culture media every 3 days. All drugs,macological compounds and ions used in the differentrimental protocols were diluted in PBS buffer.
Cell cultures
EK Cells 293 (human embryonic kidney cells) are cultivated inEM (Dulbecco’s-modified Eagle medium, Life Technologies,supplemented by 10% of fetal bovine serum (Life Technologiesand streptomicina–penicillin (200 units each, Life Technol-
s Inc). Growth is carried out fewer than 5% CO2 to 37 8C. Theium is changed every 3 days.
Whole-cell patch clamp
he culture media in the plate was replaced with an externaltion containing (in mM): 150 NaCl, 5.4 KCl, 2.0 CaCl2, 1.0l , 10 glucose and 10 HEPES (pH 7.4). The internal solution
scope (Nikon, Eclipse, TE200-u, Japan). The membrane potentialwas adjusted to �60 mV, the current recorded at 50 ms intervalsand filtered at 2 kHz using commercially available software (AxonInstruments, Inc.). Tetrodotoxin (TTX, 100 nM), a Na+ voltage-dependent channel blocker, was added to the external solution toblock excessive synaptic activity evoked by action potentialsthereby allowing the visualization of miniature synaptic currents(mIPSCs and mEPSCs). The patch electrodes were made ofborosilicate (WPI, Sarasota, USA) and prepared using a horizontalpipette puller (Sutter Instruments, USA). The resistance of theelectrodes was less than 4 MV when filled with normal internalsolution.
Stock solutions for assays containing pharmacological com-pounds, drugs or different ligands were prepared weekly indeionized distilled water and kept at 4 8C. For fast application ofdifferent compounds, a system of external tubes (200 mm internaldiameter) situated 50 mm from the cells was used. Electrophysio-logical recordings were done in the presence and absence of differentdrugs, pharmacological compounds and ions. The solutions contain-ing the different compounds flowed continuously from the inside ofthe tubes by gravity and locally bathed the cell under study.Neuronal recordings were done in the presence or absence of TTX(100 nM) depending on whether the desired information was forminiature currents or potential action recording, respectively.
2.6. Data analyse
The recordings were obtained in pClamp 9 from axoninstrument. The graphic was made using Origin 6 or prism 4, forstatistic analyze used Origin 6. The plotted are means � S.E. Forp < 0.05 the means are considered significant.
3. Results
3.1. Total venom alters cell membrane conductance
Previous reports have shown that total venom from the ChileanL. mactans spider is capable of altering normal processes in isolatedorgans (Romero et al., 2003; Romero et al., 2007). These effectshave been reported as secondary to the action of the venom onionic channels and proton pumps such as the sodium/potassiumexchanger (Robello, 1989; Chanturiya and Nikoloshina, 1994). It isnoteworthy that the Chilean species, although having similar toxiceffects, lacks the a-latrotoxin characteristic of the venom. Wedecided to investigate if there was a mechanism which wouldexplain the changes at the isolated organ level that was related tosome of the ionic alterations previously described. Therefore, westudied the effect of extracellular application of TV from L. mactans
in HEK 293 cells. Voltage–current curves for membrane con-ductance were performed, in voltage clamp mode, used adepolarization protocol from �60 to 160 mV on HEK cells in thepresence and absence of TV. Fig. 1 shows that HEK cells incubated30 min with TV present a decrease in the slope, for a conductancegraph (Voltage vs. current plot) indicating an increase inmembrane resistance (the inverses of conductance for this graph)as compared with control. This finding suggests the possibility ofionic channel closure producing an increase in membraneresistance or reduced the conductance (slope of the plot). To findout if this observation was reproducible with other known
J. Parodi, F. Romero / NeuroToxicology xxx (2008) xxx–xxx
2
ained (in mM): 120 KCl, 2.0 MgCl2, 2 ATP-Na2, 10 BAPTA, 0.5, 10 HEPES (pH 7.4). The cells were stabilized at 22 8C forin before starting the experiments. Current changes in theons were detected using the whole-cell patch clampnique (Hamill et al., 1981) with an Axopatch-200B amplifiern Instruments, Inc., Burlingame, CA) and an inverted micro-
ase cite this article in press as: Parodi J, Romero F. Synaptic effecider venom, Neurotoxicology (2008), doi:10.1016/j.neuro.2008.0
molecules, we used the same protocol in cells cultured with TEA(a potassium channel blocker) or with gramicidin, an agent knownto perforate membranes (i.e. increase in conductance). Fig. 1Bdemonstrates that both compounds vary the slope of the curves ascompared to control. Interestingly, the channel blocker TEA had asimilar effect as that observed with TV. The graph in Fig. 1C
ts of low molecular weight components from Chilean Black Widow8.006
ringe af a-llertheitheroero
vitye ofgly,thet in
ion-y ofs oftheandfectthat, thehervitythe
gestom
TEA
onic
that
bars
3
G Model
NEUTOX-899; No of Pages 6
demonstrates the membrane resistance in the absence andpresence of the venom. Cells exposed in acute manner with TVshowed a significant increase in membrane resistance.
3.2. Latrodectus venom alters membrane and action potentials in
hippocampal neurons
The effects of a-latrotoxin in the synapse has been described byseveral investigators; however the mechanism by which thevenom induces changes is still unclear. It is currently accepted thatthe interaction of a-latrotoxin with cell membranes (Krasilnikovand Sabirov, 1992; Orlova et al., 2000; Hlubek et al., 2003) resultsin the formation of a pore permeable to calcium and this is themechanism by which the venom alters synaptic activity (Henkeland Sankaranarayanan, 1999). The presence of other small-molecular weight molecules having a synergistic action have beendescribed (Kiyatkin et al., 1992; Grishin et al., 1993). Our results,however, suggest that the fragments we studied are capable ofaltering the normal functioning of isolated organs and could bemodifying membrane conductance. Fig. 2A shows representativetraces of action potentials from hippocampal neurons in theabsence or presence of TEA and TV. The traces indicate that TEAalters the action potential, lengthening the repolarization phase(Schwartzkroin and Prince, 1980) which is mediated by potassiumchannels (Woodson et al., 1978). The venom is also able to alter theaction potential kinetics in a manner parallel to TEA suggestingsimilar mechanisms. Fig. 2B current clamp traces, acquired in thepresence of TTX (100 nM) for prevented potential action, fromneurons exposed to TEA or TV. As can be seen, TEA produces alengthening on the action potential, a similar effect found with TV.Fig. 2C shows the change in membrane potential, acquired using
3.3. TV increases synaptic transmission in cultured hippocampal
neurons
As previously mentioned, a-latrotoxin is capable of altesynaptic activity, however smaller peptides appear to havcomplementary effect. Our results suggest that in the absence olatrotoxin, such as in our Chilean L. mactans model, the smafragments play an active role in producing the effect seen withvenom. This is in agreement with the systemic effects observed wthe venom from Chilean L. mactans (Romero et al., 2003; Romet al., 2007) as well as with experiments in isolated organs (Romet al., 2003). Fig. 3A shows representative traces of synaptic actiin the absence or presence of TV. Neurons cultured in the presencTV display a significant increase in synaptic events. Interestindenatured venom, boiled for 45 min at 96 8C, has no effect onneurons indicating a specific participation of the peptides presenthe venom (Fig. 3B). Fig. 3C and D reveal a time- and concentratdependent action of TV as reflected in an increase in the frequencevents with longer incubation times and higher concentrationthe venom. Both figure, suggested a pharmacology effects oversynapses, because induced to think a time depend effectsconcentration response, two characteristic of physiological efover receptors or protein. In addition, Fig. 3C demonstratesthese effects are reversible because when the venom is removedsynaptic frequency returns to control levels. On the contrary, higconcentrations of the venom are unable to alter synaptic actisuggesting an antagonistic effect (Fig. 3D), not explored butinteresting in biotechnology application. Therefore, we can sugthat the alteration in synaptic activity in the presence of the venmay be due to blockage of potassium channels, similar tosensible and changes in membrane potential.
Fig. 1. Effects of Chilean Latrodectus mactans venom extract on membrane conductance. The data were obtained from HEK 293 cells. The cultures were exposed to chr
treatment with Chilean Latrodectus mactans venom extract (7.5 mg/ml, 30 min). (A) Shows an I–y relationship in absence or presence of venom. (B) Shows I–y curves
compare the effects of gramicidin (10 mg/ml) and TEA (100 nM) with the venom. (C) Shows values for membrane resistance in the absence and presence of venom. The
are mean � S.E. from 16 different cells (*p < 0.05).
J. Parodi, F. Romero / NeuroToxicology xxx (2008) xxx–xxx
e apalata
tans
or a
current clamp, for measured the changes in the potential andreveals that both TEA and TV significantly decrease the membranepotential to values near the action potential threshold. These datademonstrate a change in the passive properties of the membranesin the presence of TV, similar to TEA, indicating the closing ofpotassium channels.
Please cite this article in press as: Parodi J, Romero F. Synaptic effecspider venom, Neurotoxicology (2008), doi:10.1016/j.neuro.2008.0
Noteworthy, TV from L. mactans has demonstrated to bpotent stimulator of synaptic activity in cultured hippocamneurons despite the fact that it lacks latrotoxin. Therefore, our dprovides the first evidence that polypeptides present in L. mac
alter synaptic activity in a manner similar to a-latrotoxin, but fdifferent mechanism.
ts of low molecular weight components from Chilean Black Widow8.006
4. D
Ppateabou
Fig. 2appli
(B) Sh
veno
Fig. 3Latro
curre
the v
4
G Model
NEUTOX-899; No of Pages 6
Plesp
. Effects of Chilean Latrodectus mactans venom extract on membrane potential from hippocampal neurons. The data were obtained from 12 DIV neurons exposed to acute
cations of Chilean Latrodectus mactans venom extract (7.5 mg/ml). (A) Shows action potential traces, in the absence and presence of TEA (100 nM) or venom (7.5 mg/ml).
ows membrane potential traces, with TTX (100 nM) in absence and presence of venom. (C) Graph showing membrane resistance values in the absence and presence of
m. The bars are mean � S.E. from eight different neurons (*p < 0.05).
. Effects of Chilean Latrodectus mactans venom extract on synaptic activity. The data were obtained from 12 DIV neurons exposed to acute applications of Chilean
dectus mactans venom extract (7.5 mg/ml). (A) Shows synaptic currents obtained in the absence and presence of venom or boiled venom. (B) Shows miniature synaptic
nt frequency in the presence of the venom. (C) Graph of synaptic frequency at different times incubation and (D) data showing the effect of different concentrations of
enom. The bars are mean � S.E. from 19 different neurons (*p < 0.05).
J. Parodi, F. Romero / NeuroToxicology xxx (2008) xxx–xxx
iscussion
revious report, in our laboratory and work for development ant (Under way in countries PCT) was provide informationt the component of the Chilean venom, form L. mactans. We
ase cite this article in press as: Parodi J, Romero F. Synaptic effecider venom, Neurotoxicology (2008), doi:10.1016/j.neuro.2008.0
described a fractionation of the venom by HPLC–MS, and we foundthe absence of the higher weight component, like a-latrotoxin, thistoxin, is the principal component in Black Widow venom andexplain mostly of systemic effect secondary to this venom. A fewreport, do it description of the low weight component, present in
ts of low molecular weight components from Chilean Black Widow8.006
6.
et al.sis of
ysiol
vity-rosci
raneanceBiol
ls inysiol
sicle
ts ofenic
dder.
aptic
nnelnary279:
eae:Evol
Ca++
244:
kovaidow
rna-nels:
tech-rane
issue
ings
low-;30:
erentchim
n EV.lack
f theacol
re ofform
sts in
nter-rosci
plied978:
neae,
5
G Model
NEUTOX-899; No of Pages 6
the venom but not explored. The Chilean venom, not presentshigher component (minor to 10 kDa, data not show) but, theChilean venom can induce similar effects to another Black Widowvenom in absence of a-latrotoxin. Agreement with previousstudies (Romero et al., 2003, 2007), our data show thatpolypeptides present in the venom from Chilean Lactrodectus
mactans spiders increase spontaneous synaptic activity in hippo-campal neurons and changes the passive properties of themembrane, cells lines.
We suggested, potassium current, for the importance of thiscurrent over membrane potential (Gutman et al., 2003) and thecontrol in the synaptic activity (Dodson and Forsythe, 2004; Yuanand Chen, 2006). Work by Grider and Makhlouf (1988) demon-strated that the tonic response in smooth muscle is dependent onthe influx of calcium into the cell. Similarly, synaptic activity isdependent on calcium homeostasis in the presynaptic button(Cousin and Robinson, 2000). Therefore, the neuronal responseobserved in the presence of total venom could be related to calciuminflux as a result of the change in membrane potential, secondaryeffect over calcium, for regulation of potassium channels (Pan andStringer, 1997; Yuan and Chen, 2006) (Fig. 2).
Studies done in isolated organ models determined thatincreased muscle contractility is due to changes in ionic con-ductance, for example potassium current (Doi et al., 2000;Darblade et al., 2006). However, we have not described particularpotassium current. Was explored the evidence of the activationor modulation of channels and the relation with another effectsof the TV. The presences of Kv1.1 in the models used, areimportant suggested, because these channels are blocked by TEAand this channels are important regulator of membrane potential(Gutman et al., 2003). All this is in relation with our data, whenshowed changes in membrane conductance in the presence ofthe venom and TEA (Fig. 1) most likely due to alterations in theTEA sensible conductances (Fig. 2). This finding is importantsince influx of calcium into the synaptic button occurs due to achange in membrane potential that can be regulated bypotassium currents (Charlton et al., 1982; Baba et al., 2003). Inaddition, voltage-dependent calcium channels are sensitive tovariations in voltage resulting in either a higher or lower synapticactivity (Parker, 2000).
However, it is important to recognize that in the classic modelfor the venom from this species of spider, a-latrotoxin isresponsible for depleting synaptic vesicles (Ashton et al., 2001)by disregulating calcium influx and increasing synaptic activity(Scheer et al., 1985; Magazanik et al., 1992) We did not study ifthese effects are reproducible with the venom from L. mactans,however we postulate a new effect of small molecular weightpeptides presents in this venom. We suggested, channelsmodulation for induce changes describes pervious in ourlaboratory and possible to think in a potassium channels, forexplain some of the effects describes or conductances sensible toTEA. More research is needed to study the chronic effects of thesepeptides in order to better understand the systemic effectsproduced by the venom in the spider L. mactans from Chile andfor postulated the channel or channels altered for this venom. Wedo it a fast report for a possible mechanism for this venom andcontinued explored the effects of single peptides, for a biotechnol-ogy development.
Conflict of interest: Patent pending.Funding source: FONDEF-D02I1024 and FONDEF-D05I1041
References
Ashton AC, Volynski KE, Lelianova VG, Orlova EV, Van Renterghem C, Canepari M,Alpha-latrotoxin, acting via two Ca2
+-dependent pathways, triggers exocytotwo pools of synaptic vesicles. J Biol Chem 2001;276:44695–703.
Auger C, Marty A. Quantal currents at single-site central synapses. J Ph2000;526(Pt 1):3–11.
Baba A, Yasui T, Fujisawa S, Yamada RX, Yamada MK, Nishiyama N, et al. Actievoked capacitative Ca2
+ entry: implications in synaptic plasticity. J Neu2003;23:7737–41.
Chanturiya AN, Nikoloshina HV. Correlations between changes in membcapacitance induced by changes in ionic environment and the conductof channels incorporated into bilayer lipid membranes. J Membr1994;137:71–7.
Charlton MP, Smith SJ, Zucker RS. Role of presynaptic calcium ions and channesynaptic facilitation and depression at the squid giant synapse. J Ph1982;323:173–93.
Cousin MA, Robinson PJ. Ca(2+) influx inhibits dynamin and arrests synaptic veendocytosis at the active zone. J Neurosci 2000;20:949–57.
Darblade B, Behr-Roussel D, Oger S, Hieble JP, Lebret T, Gorny D, et al. Effecpotassium channel modulators on human detrusor smooth muscle myogphasic contractile activity: potential therapeutic targets for overactive blaUrology 2006;68:442–8.
Dodson PD, Forsythe ID. Presynaptic K+ channels: electrifying regulators of synterminal excitability. Trends Neurosci 2004;27:210–7.
Doi S, Damron DS, Ogawa K, Tanaka S, Horibe M, Murray PA. K(+) chainhibition, calcium signaling, and vasomotor tone in canine pulmoartery smooth muscle. Am J Physiol Lung Cell Mol Physiol 2000;L242–251.
Garb JE, Gonzalez A, Gillespie RG. The Black Widow spider genus Latrodectus (AranTheridiidae): phylogeny, biogeography, and invasion history. Mol Phylogenet2004;31:1127–42.
Grider JR, Makhlouf GM. Contraction mediated by Ca++ release in circular andinflux in longitudinal intestinal muscle cells. J Pharmacol Exp Ther 1988;432–7.
Grishin EV, Himmelreich NH, Pluzhnikov KA, Pozdnyakova NG, Storchak LG, VolTM, et al. Modulation of functional activities of the neurotoxin from Black Wspider venom. FEBS Lett 1993;336:205–7.
Gutman GA, Chandy KG, Adelman JP, Aiyar J, Bayliss DA, Clapham DE, et al. Intetional Union of Pharmacology. XLI. Compendium of voltage-gated ion chanpotassium channels. Pharmacol Rev 2003;55:583–6.
Hamill OP, Marty A, Neher E, Sakmann B, Sigworth FJ. Improved patch-clampniques for high-resolution current recording from cells and cell-free membpatches. Pflugers Arch 1981;391:85–100.
Henkel AW, Sankaranarayanan S. Mechanisms of alpha-latrotoxin action. Cell TRes 1999;296:229–33.
Hlubek M, Tian D, Stuenkel EL. Mechanism of alpha-latrotoxin action at nerve endof neurohypophysis. Brain Res 2003;992:30–42.
Kiyatkin N, Dulubova I, Chekhovskaya I, Lipkin A, Grishin E. Structure of themolecular weight protein copurified with alpha-latrotoxin. Toxicon 1992771–4.
Krasilnikov OV, Sabirov RZ. Comparative analysis of latrotoxin channels of diffconductance in planar lipid bilayers. Evidence for cluster organization. BioBiophys Acta 1992;1112:124–8.
Magazanik LG, Fedorova IM, Kovalevskaya GI, Pashkov VN, Bulgakov OV, GrishiSelective presynaptic insectotoxin (alpha-latroinsectotoxin) isolated from BWidow spider venom. Neuroscience 1992;46:181–8.
Nouailhetas VL, Shimuta SI, Paiva AC, Paiva TB. Calcium and sodium dependence obiphasic response of the guinea-pig ileum to agonists. Eur J Pharm1985;116:41–7.
Orlova EV, Rahman MA, Gowen B, Volynski KE, Ashton AC, Manser C, et al. Structualpha-latrotoxin oligomers reveals that divalent cation-dependent tetramersmembrane pores. Nat Struct Biol 2000;7:48–53.
Pan E, Stringer JL. Role of potassium and calcium in the generation of cellular burthe dentate gyrus. J Neurophysiol 1997;77:2293–9.
Parker D. Activity and calcium-dependent mechanisms maintain reliable ineuron synaptic transmission in a rhythmic neural network. J Neu2000;20:1754–66.
Robello M. Dependence of the conductance of the alpha-latrotoxin channel on appotential and potassium concentration. Biochim Biophys Acta 1989;179–84.
Romero F, Altieri E, Urrutia M, Jara J. Venom of Latrodectus mactans from Chile (Ara
J. Parodi, F. Romero / NeuroToxicology xxx (2008) xxx–xxx
hno-Steril
um. J
atory
Acknowledgments
We thank to Dr. Luis Aguayo, by the opportunity to useequipment and expertise to perform these studies
F.R. and J.P. were supported by the Fondef-Conicyt Chile No.DO5I10416.
Please cite this article in press as: Parodi J, Romero F. Synaptic effecspider venom, Neurotoxicology (2008), doi:10.1016/j.neuro.2008.0
Theridiidae): effect on smooth muscle. Rev Biol Trop 2003;51:305–12.Romero F, Cunha MA, Sanchez R, Ferreira AT, Schor N, Oshiro ME. Effects of arac
toxin on intracellular pH and calcium in human spermatozoa. Fertil2007;87:1345–9.
Sanborn BM. Relationship of ion channel activity to control of myometrial calciSoc Gynecol Invest 2000;7:4–11.
Scheer H, Madeddu L, Wanke E, Ferroni A, Meldolesi J. ‘‘Pure’’ presynaptic stimultoxins and ion transport. Regul Pept Suppl 1985;4:53–8.
ts of low molecular weight components from Chilean Black Widow8.006
SchenL1
Schw1
Shimtp
6
G Model
NEUTOX-899; No of Pages 6
Plesp
one H, Correa LE. Some practical knowledge of the biology of the spideratrodectus mactans and the latrodectism syndrome in Chile. Bol Chil Parasitol985;40:18–23.artzkroin PA, Prince DA. Effects of TEA on hippocampal neurons. Brain Res980;185:169–81.uta SI, Nouailhetas VL, Valero VB, Paiva AC, Paiva TB. Effect of sodium concentra-ion and of atropine on the contractile response of the guinea-pig ileum tootassium ions. Pflugers Arch 1982;394:186–90.
Varghese A, Tenbroek EM, Coles J Jr, Sigg DC. Endogenous channels in HEK cells andpotential roles in HCN ionic current measurements. Prog Biophys Mol Biol2006;90:26–37.
Woodson PB, Schlapfer WT, Barondes SH. Amplitude and rate of decay of post-tetanicpotentiation are controlled by different mechanisms. Brain Res 1978;157:33–46.
Yuan LL, Chen X. Diversity of potassium channels in neuronal dendrites. Prog Neurobiol2006;78:374–89.
J. Parodi, F. Romero / NeuroToxicology xxx (2008) xxx–xxx
ase cite this article in press as: Parodi J, Romero F. Synaptic effects of low molecular weight components from Chilean Black Widowider venom, Neurotoxicology (2008), doi:10.1016/j.neuro.2008.08.006
Recommended