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What is TCM?

TCM stands for traditional chinese medicine. It is the

traditional form of medication used by the chinese for

thousands of years.

In recent years, there has been an increase in researches

conducted to learn more about the pharmacological actions of

TCM herbs in an attempt to find out how TCM works.

Currently, the effect of various TCM herbs on VSMCs is still a

field that needs a lot of future researchand studies.

In this section, we shall only focus on a few herbs used in TCM

and how they may affect the calcium level as well as muscle

contraction in VSMCs.

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1.) Yang herbs Yang herbs are used in TCM for

various Yang deficiency syndromes.

2.) Panax notoginseng dried root ofPanax notoginseng

belonging to the family of

Araliaceae.

3.) Salvia miltiorrhiza dried root ofSalvia miltiorrhiza thatDanshen belongs to the family ofLabiatae.

4.) Digitalis purpurea dried leaf of the foxglove plant.

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ROS

Due to the oxidative process of the mitochondria, the

mitochondria generates a lot ofreactive oxygen species.

The mitochondrial DNA in addition to proteins in the inner

membrane of mitochondriaare highly vulnerable to

damage by ROS.

When the balance between antioxidants and ROS are

disrupted by diseases/aging, many age-related diseases,

suchas cancer, can occur.

Several Yang tonic herbs possess anti-oxidant activities.

For example,Water extracts ofRhizoma Drynariae and

Cortex Eucommiae were found to inhibit oxidant

production from rat osteoblasts.

Many Yang drugs contain antioxidants whichneutralize effect ofROS of mitochondria Since ROS

activates protein kinase C (PKC), and PKC increases

muscle contraction. Inhibiting ROS may cause a

decrease in contractility in VSMCs. ( this above argument

is entirely my own opinion, do not come from scientific

source).

Ko, K.M., Mak, D.H., Chiu, P.Y., Poon, M.K.,

2004. Pharmacological basis of 'Yang-invigoration' in Chinese medicine. Trends

Pharmacol Sci 25, 3-6.

Anti-oxidants

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The total saponins ofPanax notoginseng have been used

in clinic for the treatment of cardiovascular diseases and

stroke in China since 1982.

Ginsenoside-Rd from total saponins inhibits the

contractile responses induced by activations ofalpha1

adrenoceptor by phenylephrine.

Ginsenoside-Rd does this by inhibiting calcium influx

through receptor operated channel (ROCC) and store-

operated calcium channel (SOCC) in VSMCs. It does not

show inhibition of VOCCs, and it does not inhibit calcium

release in VSMCs.

It is known that pathological processes like ischemia-

induced brain neuron injury are coupled withintracellular

calcium overload which is usually due to calcium influx

throughROCC or SOCC rather than VOCC.

Ginsenoside-Rd might provide a useful clue for the

development of new calcium entry blocker ofROCC and

SOCC.

Plasma

Membrane

SOCC VOCCROCC

Guan, Y.Y., Zhou, J.G., Zhang, Z., Wang, G.L., Cai, B.X., Hong, L.,

Qiu, Q.Y., He, H., 2006. Ginsenoside-Rd from panax notoginseng

blocks Ca2+ influx through receptor- and store-operated Ca2+channels in vascular smooth muscle cells. Eur J Pharmacol 548,

129-136.

panax notoginseng

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Digitalis purpurea is of great clinical significance.

It is used in TCM in the treatment of chronic heart

diseases.

It functions to increase heart contractility, increase heart

stroke volume and to maintain a stable heart beat. It is

used to treat congestive heart failure.

Digitalis purpurea can cause Inhibition of the Na+-K+

pump. This leads to ahigher level of Na+ inside the cell.The diminished Na+ gradient results in slower extrusion

of Ca2+ by the NCX. The subsequent increase in the

intracellular level of Ca2+ enhances the contractility of

cardiac muscle.

Whether it also enhances contractility of VSMCs requires

further investigation.

Berg, J.M., Tymoczko, J.L., Stryer, L.,

Clarke, N.D. , 2002. Biochemistry. W. H.

Freeman and Company. Chapter 13.

Plasma

Membrane

Na+Na+

Na+Na+

Ca2+

Na+Na+

Na+-K+

pumpNCX

Ca2+

Calcium

extrusion

inhibited

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Danshen is the dried root of Salvia miltiorrhiza that

belongs to the family of Labiatae. It is a traditional

Chinese medicine commonly used for the treatment of

cardiovascular diseases suchas angina pectoris,

myocardial infarction and stroke.

The content of danshen can be separated into lipid-

soluble and water-soluble fractions.

From the water-soluble fraction, Salvianolic

acid B is the component most studied.

It has adilatory effect on rat coronary arteries.

Salvianolic acid B achieves this mainly by inhibition of

Ca2+influx into VSMCs and by stimulating the opening of

K+ channels.

Recent finding also suggests salvianolic acid B can

evoke the opening of BK channels of porcine coronary

artery smooth muscle cells through the activation of

guanylate cyclase.

Plasma

Membrane

Ca2+Ca2+

Ca2+

Calcium

channels

BK

channels

K+K+K+

One of the lipid-soluble constituents of danshen,

tanshinone IIA has been suggested to function as

calcium channel antagonists.

Tanshinone IIA has previously been shown to possess an

anti-anginal effect through its L-type calcium channel

blocking activities.

VOCC

DanShen

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1.) Lam, F.F., Seto, S.W., Kwan, Y.W., Yeung, J.H., Chan, P., 2006. Activation

of the iberiotoxin-sensitive BKCa channels by salvianolic acid B of the porcine

coronary artery smooth muscle cells. Eur J Pharmacol 546, 28-35.

2.) Lam, F.F., Yeung, J.H., Kwan, Y.W., Chan, K.M., Or, P.M., 2006. Salvianolic

acid B, an aqueous component of danshen (Salvia miltiorrhiza), relaxes rat

coronary artery by inhibition of calcium channels. Eur J Pharmacol 553, 240-

245.

3.) Lam, F.F., Yeung, J.H., Cheung, J.H., Or, P.M., 2006. Pharmacological

evidence for calcium channel inhibition by danshen (Salvia miltiorrhiza) on rat

isolated femoral artery. J Cardiovasc Pharmacol 47, 139-145.