title: Beta-adrenergic blocking effects and cardiodepressant activity of penbutolol and its two optical isomers in the guinea-pig left atrium.
abstract: The beta-adrenoceptor blocking potency and cardiodepressant activity of penbutolol and its two isomers have been evaluated in the guinea-pig left atrium in order to determine if the two properties are related. While (-)-penbutolol was ten times more potent than (+)-penbutolol and three times more potent than (+/-)-penbutolol as a beta-adrenoceptor antagonist, the three compounds showed a similar activity as cardiodepressant agents. These results seem to demonstrate that it is unlikely that this depressant action can be related to the antagonism of beta adrenoceptors.
mesh_terms: D000818:Animals; D003864:Depression, Chemical; D006168:Guinea Pigs; D066298:In Vitro Techniques; D009200:Myocardial Contraction / Q000187:drug effects*; D010394:Penbutolol / Q000494:pharmacology*; D011412:Propanolamines / Q000494:pharmacology*; D011943:Receptors, Adrenergic, beta / Q000187:drug effects*; D013237:Stereoisomerism
chemical_list: D011412:Propanolamines; D011943:Receptors, Adrenergic, beta; D010394:Penbutolol