title: Vasorelaxing effect of mesaconitine, an alkaloid from Aconitum japonicum, on rat small gastric artery: possible involvement of endothelium-derived hyperpolarizing factor.
abstract: Aconiti tuber, roots of aconite (Aconitum japonicum), has been used for centuries in Japan and China to increase peripheral body temperature. We previously reported that mesaconitine, an alkaloid from Aconitum japonicum, elicits endothelium-dependent and nitric oxide-mediated relaxation in isolated rat aorta. In the present study, we investigated the effect of mesaconitine on isolated rat small gastric arteries. Mesaconitine elicited a concentration-dependent (10, 30, 100 microM) vasorelaxation in isolated rat gastric artery precontracted with norepinephrine, which was resistant to N(omega)-nitro-L-arginine (L-NNA) (an inhibitor of nitric oxide synthase) and indomethacin (an inhibitor of cyclooxygenase). The L-NNA- and indomethacin-resistant relaxation by mesaconitine was mainly endothelium-dependent, inhibited by high K+ (30 mM), and inhibited by a combination of Ca2+-dependent K channel blockers, charybdotoxin and apamin. The relaxation by mesaconitine was proportional to the external Ca2+ concentration. These results suggest that mesaconitine elicits vasorelaxation of isolated rat small gastric artery mainly via release of endothelium-derived hyperpolarizing factor.
authors.affiliation: Department of Physiology and Physiopathology, Ghent University, Gent, Belgium.
authors.forename: Mana
authors.initials: M
authors.lastname: Mitamura
authors.forename: Koen
authors.initials: K
authors.lastname: Boussery
authors.forename: Syunji
authors.initials: S
authors.lastname: Horie
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Murayama
authors.forename: Johan
authors.initials: J
authors.lastname: Van de Voorde
mesh_terms: D000157:Aconitine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D031841:Aconitum; D000470:Alkaloids / Q000494:pharmacology; D000818:Animals; D001685:Biological Factors / Q000378:metabolism / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000502:physiology; D005260:Female; D066298:In Vitro Techniques; D018517:Plant Roots; D051381:Rats; D017208:Rats, Wistar; D013270:Stomach / Q000098:blood supply / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects* / Q000502:physiology
chemical_list: D000470:Alkaloids; D001685:Biological Factors; C067410:endothelium-dependent hyperpolarization factor; C019470:mesaconitine; D000157:Aconitine