title: Aspects of the cardiovascular pharmacology of exaprolol.
abstract: This study confirms that exaprolol is a potent beta-adrenoceptor antagonist, having a pA2 value of 9.8 for the inhibition of the inotropic and chronotropic responses of guinea-pig isolated atrial preparations to isoprenaline. In the anaesthetized cat, exaprolol blocks both the myocardial stimulatory and vasodilating effects of isoprenaline, suggesting that it is a non-selective antagonist at beta-adrenoceptors. Exaprolol also has direct electrophysiological effects on cardiac (Purkinje) tissue, reducing the rate of rise of phase 0 of the action potential. This direct action together with its marked blockade of beta-adrenoceptors may explain the drug's ability to markedly suppress the ischaemic ventricular arrhythmias that follow coronary artery occlusion in anaesthetized rats.
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000758:Anesthesia; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000503:physiopathology / Q000517:prevention & control; D002415:Cats; D003327:Coronary Disease / Q000503:physiopathology; D003331:Coronary Vessels / Q000502:physiology; D005260:Female; D006168:Guinea Pigs; D006439:Hemodynamics / Q000187:drug effects*; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000037:antagonists & inhibitors; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D010210:Papillary Muscles / Q000187:drug effects; D011412:Propanolamines / Q000494:pharmacology*; D011690:Purkinje Fibers / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D012756:Sheep; D013045:Species Specificity
chemical_list: D000319:Adrenergic beta-Antagonists; D011412:Propanolamines; D007545:Isoproterenol; C012969:exaprolol