Stereospecific effects of ginsenoside Rg3 epimers on swine coronary artery contractions.
Previous reports have shown that ginseng saponins, the active ingredients of Panax ginseng, induce relaxation of hormone- or high K(+)-induced blood vessel contraction. We recently demonstrated that 20(R)- and 20(S)-ginsenoside Rg(3) epimers regulate ion channel activities in a stereospecific manner. Here, we examined whether ginsenoside Rg(3) epimers also exhibit differential effects on swine coronary artery contractions induced by high K(+) or 5-HT. We found that treatment with 20(S)- but not 20(R)-ginsenoside Rg(3) caused a potent concentration-dependent, endothelium-independent relaxation of coronary artery contraction induced by 25 mM KCl. However, treatment with both 20(S)- and 20(R)-ginsenoside Rg(3) induced a significant, concentration-dependent relaxation of 3 microM 5-HT-induced coronary artery contractions in intact samples, while only 20(S)-ginsenoside Rg(3) inhibited coronary artery contraction in endothelium-denuded arteries. 20(S)- but not 20(R)-ginsenoside Rg(3) inhibited L-type Ca(2+) channel currents in a dose- and voltage-dependent manner. These results indicate that 20(S)- and 20(R)-ginsenoside Rg(3) epimers might exhibit stereospecific relaxation effects on swine coronary artery contractions caused by high K(+) and 5-HT receptor activation.
Kim
Jong-Hoon
JH
Ginsentology Research Laboratory, Department of Physiology, College of Veterinary Medicine, and Bio/Molecular Informatics Center, Konkuk University, Chungju, Seoul 143-701, Korea.
Lee
Jun-Ho
JH
Jeong
Sang Min
SM
Lee
Byung-Hwan
BH
Yoon
In-Soo
IS
Lee
Joon-Hee
JH
Choi
Sun-Hye
SH
Kim
Dong-Hyun
DH
Park
Tae-Kyu
TK
Kim
Bo-Kyung
BK
Nah
Seung-Yeol
SY
D000818:Animals; D020746:Calcium Channels, L-Type / Q000378:metabolism; D003331:Coronary Vessels / Q000187:drug effects* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D036145:Ginsenosides / Q000737:chemistry / Q000494:pharmacology*; D066298:In Vitro Techniques; D015394:Molecular Structure; D011189:Potassium Chloride / Q000494:pharmacology; D011985:Receptors, Serotonin / Q000378:metabolism; D013237:Stereoisomerism; D013552:Swine; D014661:Vasoconstriction / Q000187:drug effects*; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014665:Vasodilator Agents / Q000737:chemistry / Q000494:pharmacology*
D020746:Calcium Channels, L-Type; D036145:Ginsenosides; D011985:Receptors, Serotonin; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; C097367:ginsenoside Rg3; D011189:Potassium Chloride