title: Effect of KRN2391, a novel vasodilator, on endothelin-1-induced contraction of porcine coronary artery: comparison with cromakalim, nitroglycerin and nifedipine.
abstract: The relaxant effects of KRN2391 (K channel opener and nitrate-like), cromakalim (K channel opener), nitroglycerin (nitrate-like) and nifedipine (Ca channel blocker) were investigated in porcine isolated coronary arteries contracted by endothelin-1 and KCl. KRN2391, nitroglycerin and cromakalim concentration-dependently inhibited the 10(-8) M endothelin-1-induced contraction, but less potently inhibited the 40 mM KCl-induced contraction. Nifedipine concentration-dependently inhibited the 40 mM KCl-induced contraction more strongly than the 10(-8) M endothelin-1-induced contraction. KRN2391 and nitroglycerin produced a complete relaxation of arteries contracted by endothelin-1 at its maximum effect. Cromakalim and nifedipine, both at 3 x 10(-5) M, produced 83.9% and 73.3% of the complete relaxation of the endothelin-1-induced contraction, respectively. In the 40 mM KCl-induced contraction, nifedipine produced a complete relaxation, but KRN2391, cromakalim and nitroglycerin, all at 3 x 10(-5) M, produced a relaxation of 62.7%, 27.1% and 79.4%, respectively. The combination of cromakalim and nitroglycerin relaxed the 10(-8) M endothelin-1- and 40 mM KCl-induced contractions in a concentration-dependent manner. The relaxant effect of this combination was greater against the endothelin-1-induced contraction than against the 40 mM KCl-induced contraction. The maximum relaxation of the combination of cromakalim (3 x 10(-5) M) and nitroglycerin (3 x 10(-6) M) was complete for the endothelin-1-induced contraction but a relaxation of 77.8% was obtained for the 40 mM KCl-induced contraction, i.e. the relaxant effects using this combination were greater than those by cromakalim (3 x 10(-5) M) alone.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Pharmaceutical Research Laboratory, Kirin Brewery Co., Ltd., Gunma, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Miwa
authors.forename: H
authors.initials: H
authors.lastname: Kasai
authors.forename: K
authors.initials: K
authors.lastname: Motoki
authors.forename: Y
authors.initials: Y
authors.lastname: Jinno
authors.forename: T
authors.initials: T
authors.lastname: Yokoyama
authors.forename: H
authors.initials: H
authors.lastname: Fukushima
authors.forename: N
authors.initials: N
authors.lastname: Ogawa
mesh_terms: D000818:Animals; D001158:Arteries / Q000187:drug effects; D001578:Benzopyrans / Q000494:pharmacology; D003331:Coronary Vessels / Q000187:drug effects*; D019806:Cromakalim; D004305:Dose-Response Relationship, Drug; D016232:Endothelins / Q000494:pharmacology*; D066298:In Vitro Techniques; D009543:Nifedipine / Q000494:pharmacology; D005996:Nitroglycerin / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology*; D011758:Pyrroles / Q000494:pharmacology; D013552:Swine; D014661:Vasoconstriction / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D001578:Benzopyrans; D016232:Endothelins; D011725:Pyridines; D011758:Pyrroles; D014665:Vasodilator Agents; D019806:Cromakalim; C070492:N-cyano-N'-(2-nitroxyethyl)-3-pyridinecarboximidamide methanesulfonate; D005996:Nitroglycerin; D009543:Nifedipine