title: Vascular relaxing mechanism of denopamine in isolated canine coronary, femoral, mesenteric, and renal arteries.
abstract: We investigated the mechanism of vascular relaxation produced by denopamine (deno), an oral positive inotropic agent that has selective beta 1-adrenergic action. Deno concentration-dependently (0.1 microM-30 microM) relaxed ring segments of canine femoral, mesenteric, and renal arteries which were partially precontracted with 1 micron phenylephrine or norepinephrine, but did not relax those precontracted with 5 microM prostaglandin F2 alpha or 40 mM K+. The relaxation was not significantly inhibited by pretreatment with 10 microM propranolol or metoprolol. Deno produced a parallel rightward shift in concentration-response curves to phenylephrine in femoral and renal arteries. The Schild plot yielded linear regressions of slopes of 1.301 +/- 0.106 and 0.823 +/- 0.122, respectively, which were not significantly different from unity. The pA2 values of Deno against phenylephrine in femoral and renal arteries were 5.41 +/- 0.03 and 5.76 +/- 0.06, respectively. On the other hand, Deno concentration-dependently (10 nM-10 microM) relaxed ring segments of canine coronary arteries which were partially precontracted with 5 microM prostaglandin F2 alpha. The relaxation was significantly inhibited by pretreatment with 10 microM metoprolol. In conclusion, vascular smooth muscle relaxation by Deno was mediated through beta 1-adrenergic action in canine coronary arteries and through the blocking effect of alpha-adrenoceptors in canine femoral, mesenteric, and renal arteries.
authors.affiliation: Third Department of Internal Medicine, Ohashi Hospital, Toho University School of Medicine, Tokyo, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Aikawa
authors.forename: M
authors.initials: M
authors.lastname: Moroi
authors.forename: A
authors.initials: A
authors.lastname: Namiki
authors.forename: T
authors.initials: T
authors.lastname: Yamaguchi
authors.forename: K
authors.initials: K
authors.lastname: Machii
authors.forename: K
authors.initials: K
authors.lastname: Koike
authors.forename: I
authors.initials: I
authors.lastname: Takayanagi
mesh_terms: D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000818:Animals; D002316:Cardiotonic Agents / Q000494:pharmacology*; D003331:Coronary Vessels / Q000187:drug effects; D015237:Dinoprost / Q000494:pharmacology; D004285:Dogs; D004983:Ethanolamines / Q000494:pharmacology*; D005260:Female; D005263:Femoral Artery / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects; D008790:Metoprolol / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D009638:Norepinephrine / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D012077:Renal Artery / Q000187:drug effects; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D000318:Adrenergic beta-Agonists; D002316:Cardiotonic Agents; D004983:Ethanolamines; D014665:Vasodilator Agents; D010656:Phenylephrine; D011433:Propranolol; D015237:Dinoprost; D008790:Metoprolol; C037293:denopamine; D009638:Norepinephrine