Gomisin A from Schisandra chinensis induces endothelium-dependent and direct relaxation in rat thoracic aorta.
Schisandra chinensis (SC), a member of the Magnoliaceae family, has been used to improve the vascular health for postmenopausal women in Korea. In order to provide some scientific rationales for such effectiveness, this study investigated the vascular effects of gomisin A (GA) from SC. In the endothelium (ED)-intact rings of rat thoracic aorta, GA (1 x 10 (-6) to 3 x 10 (-4) M) caused a concentration-dependent relaxation which was markedly attenuated not only by removal of ED but also by pretreatment with N(G)-nitro- L-arginine (10 (-4) M) or 1 H-[1,2,4]oxadiazol[4,3- a]quinoxalin-1-one (3 x 10 (-5) M). Direct measurement of nitrite, a metabolite of nitric oxide (NO), confirmed that NO production in isolated aorta was increased by GA. In the ED-denuded specimens, the relaxation by GA was not abolished but reduced significantly. The relaxation by GA in ED-denuded aortic rings were clearly inhibited by calyculin A (3 x 10 (-8) M), an inhibitor of MLC phosphatase. Furthermore, the phenylephrine-enhanced phosphorylation ratio of MLC was significantly attenuated by GA. Based on these results, it is suggested that GA induced vascular relaxation by partially activating ED-dependent NO pathway, and partially dephosphorylation of MLC.
Park
Ji Young
JY
Department of Pharmacology, College of Medicine, and MRC for Ischemic Tissue Regeneration and Medical Research Institute, Pusan National University, Busan, Korea.
Lee
Seung Jin
SJ
Yun
Mi Ran
MR
Seo
Kyo Won
KW
Bae
Sun Sik
SS
Park
June Woo
JW
Lee
You Jin
YJ
Shin
Woo Jung
WJ
Choi
Young Whan
YW
Kim
Chi Dae
CD
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects; D034242:Cyclooctanes / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D004149:Dioxoles / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects; D005638:Fruit; D017705:Lignans / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects*; D008517:Phytotherapy; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D051381:Rats; D017207:Rats, Sprague-Dawley; D032141:Schisandra; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use
D034242:Cyclooctanes; D004149:Dioxoles; D017705:Lignans; D010936:Plant Extracts; D014665:Vasodilator Agents; C033585:schizandrol B