Alprenolol and bromoacetylalprenololmenthane are competitive slowly reversible antagonists at the beta 1-adrenoceptors of rat left atria.
We studied the effects of alprenolol and bromoacetylalprenololmenthane (BAAM) on rat left atria. Alprenolol and BAAM at 10(-7), 3 x 10(-7), and 10(-6) M inhibited the cardiac stimulation response slightly, which is indicative of membrane-stabilizing activity independent of beta-adrenoceptor blockade. This membrane-stabilizing activity was readily reversible. Alprenolol and BAAM also caused surmountable antagonism of isoprenaline responses, and this beta 1-adrenoceptor antagonism was slowly reversible. Inhibition of the isoprenaline responses with alprenolol and BAAM at 10(-6) M was at equilibrium after 60 min, which is indicative of reversible antagonism. We conclude that alprenolol and BAAM are competitive slowly reversible beta 1-adrenoceptor antagonists on rat left atria.
Surman
A J
AJ
Department of Pharmacology, School of Medicine, University of Auckland, New Zealand.
Doggrell
S A
SA
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000526:Alprenolol / Q000031:analogs & derivatives* / Q000494:pharmacology*; D000818:Animals; D016275:Atrial Function; D006325:Heart Atria / Q000187:drug effects; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000037:antagonists & inhibitors; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar
D000319:Adrenergic beta-Antagonists; C045331:bromoacetylalprenololmenthane; D000526:Alprenolol; D007545:Isoproterenol