title: Characterization of beta 3-adrenoceptor-mediated relaxation in rat abdominal aorta smooth muscle.
abstract: The present study was carried out to characterize beta-adrenoceptor subtypes mediating relaxation of rat abdominal aorta smooth muscle. (-)-Isoprenaline and a nonconventional beta(3)-adrenoceptor agonist, (+/-)-[4-[3-[(1,1-dimethylethyl)amino]-2-hydroxypropoxy]-1,3-dihydro-2H-benzimidazol-2-one] hydrochloride ((+/-)-CGP12177A), induced concentration-dependent relaxation of (-)-phenylephrine (0.3 microM) preconstricted spiral preparations. Pretreatment with a combination of (+/-)-2-hydroxy-5-[2-[[2-hydroxy-3-[4-[1-methyl-4-(trifluoromethyl)-1H-imidazol-2-yl]phenoxy]propyl]amino]ethoxy]-benzamide methanesulfonate (CGP20712A, a selective beta(1)-adrenoceptor antagonist) and (+/-)-1-[2,3-(dihydro-7-methyl-1H-inden-4-yl)oxy]-3-[(1-methylethyl)amino]-2-butanol hydrochloride (ICI-118,5511, a selective beta(2)-adrenoceptor antagonist) (0.1 microM for each) produced a 14-fold rightward shift of the concentration-response curve for (-)-isoprenaline; however, the relaxation in response to (+/-)-CGP12177A was unaffected by the blockade of beta(1)- and beta(2)-adrenoceptors. In the presence of CGP20712A and ICI-118,551 (0.1 microM for each), the concentration-response curves for (-)-isoprenaline and (+/-)-CGP12177A were shifted to the right by a nonselective beta(1)-, beta(2)- and beta(3)-adrenoceptor antagonist, (+/-)-bupranolol (3 and 10 microM). These results clearly suggest that beta(3)-adrenoceptors are involved in beta-adrenoceptor-mediated relaxation of rat abdominal aorta smooth muscle.
authors.affiliation: Department of Chemical Pharmacology, Toho University School of Pharmaceutical Sciences, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan.
authors.forename: Mayumi
authors.initials: M
authors.lastname: Matsushita
authors.forename: Takahiro
authors.initials: T
authors.lastname: Horinouchi
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Tanaka
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Tsuru
authors.forename: Katsuo
authors.initials: K
authors.lastname: Koike
mesh_terms: D058667:Adrenergic beta-3 Receptor Agonists; D058673:Adrenergic beta-3 Receptor Antagonists; D000818:Animals; D001012:Aorta, Abdominal / Q000187:drug effects / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology*; D011412:Propanolamines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D022702:Receptors, Adrenergic, beta-3 / Q000502:physiology*; D014661:Vasoconstriction / Q000187:drug effects / Q000502:physiology*; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology*
chemical_list: D058667:Adrenergic beta-3 Receptor Agonists; D058673:Adrenergic beta-3 Receptor Antagonists; D011412:Propanolamines; D022702:Receptors, Adrenergic, beta-3; D007545:Isoproterenol; C033394:CGP 12177