title: Inhibition of intracellular calcium elevation and blunting of vasopressor response due to serotonin by ginkgolide B.
abstract: The vascular effects of each individual composition in the extract of Ginkgo biloba have not been clarified. In this work, we have investigated whether ginkgolide B (GKB), a terpene lactone component from Ginkgo biloba, modulates intracellular calcium ([Ca (2+)] i) of vascular smooth muscle cells (smc) and how it influences the vasopressor response in vitro caused by serotonin (5-HT). GKB (3.2 - 9.6 microM) selectively decreased serotonin-induced [Ca (2+)] i elevations in cultured smc from bovine aorta in dose-dependent manner, while it had no effects on both resting [Ca (2+)] i and potassium-elicited [Ca (2+)] i elevations. On the other hand, GKB in a concentration of 3.2 - 9.6 microM moderately decreased the maximal pressor efficacy of serotonin by 14 - 45 % in rat mesenteric vascular beds, and the EC50 remained unchanged. The comparison study also showed GKB had no effects on noradrenaline-elicited pressor reactions. These results implicate that GKB may selectively inhibit serotonin-mediated [Ca (2+)] i mobilization in vascular smc and non-competitively alleviate the vasopressor effect of serotonin in vitro.
authors.affiliation: Department of Pharmacology, School of Medicine, Nanjing University, Nanjing, PR China. YwangH8@sohu.com
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
authors.forename: Ying-Qun
authors.initials: YQ
authors.lastname: Yu
authors.forename: Jian-Guo
authors.initials: JG
authors.lastname: Xu
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D002118:Calcium / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002417:Cattle; D002478:Cells, Cultured; D004224:Diterpenes; D004305:Dose-Response Relationship, Drug; D016166:Free Radical Scavengers / Q000494:pharmacology*; D020441:Ginkgo biloba; D046934:Ginkgolides; D007783:Lactones / Q000737:chemistry / Q000494:pharmacology*; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects* / Q000502:physiology; D015394:Molecular Structure; D009638:Norepinephrine / Q000494:pharmacology; D010936:Plant Extracts / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000494:pharmacology*; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014700:Verapamil / Q000494:pharmacology
chemical_list: D002121:Calcium Channel Blockers; D004224:Diterpenes; D016166:Free Radical Scavengers; D046934:Ginkgolides; D007783:Lactones; D010936:Plant Extracts; D014662:Vasoconstrictor Agents; D012701:Serotonin; D011189:Potassium Chloride; D014700:Verapamil; C045856:ginkgolide B; D002118:Calcium; D009638:Norepinephrine