title: Stereospecific effects of ginsenoside Rg3 epimers on swine coronary artery contractions.
abstract: 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.
authors.affiliation: Ginsentology Research Laboratory, Department of Physiology, College of Veterinary Medicine, and Bio/Molecular Informatics Center, Konkuk University, Chungju, Seoul 143-701, Korea.
authors.forename: Jong-Hoon
authors.initials: JH
authors.lastname: Kim
authors.forename: Jun-Ho
authors.initials: JH
authors.lastname: Lee
authors.forename: Sang Min
authors.initials: SM
authors.lastname: Jeong
authors.forename: Byung-Hwan
authors.initials: BH
authors.lastname: Lee
authors.forename: In-Soo
authors.initials: IS
authors.lastname: Yoon
authors.forename: Joon-Hee
authors.initials: JH
authors.lastname: Lee
authors.forename: Sun-Hye
authors.initials: SH
authors.lastname: Choi
authors.forename: Dong-Hyun
authors.initials: DH
authors.lastname: Kim
authors.forename: Tae-Kyu
authors.initials: TK
authors.lastname: Park
authors.forename: Bo-Kyung
authors.initials: BK
authors.lastname: Kim
authors.forename: Seung-Yeol
authors.initials: SY
authors.lastname: Nah
mesh_terms: 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*
chemical_list: D020746:Calcium Channels, L-Type; D036145:Ginsenosides; D011985:Receptors, Serotonin; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; C097367:ginsenoside Rg3; D011189:Potassium Chloride