Beta-adrenoceptor selectivity of dobutamine: in vivo and in vitro studies.
We compared the beta-adrenoceptor stimulant actions of dobutamine and (-)-isoprenaline in isolated tissue preparations (atria, trachea, and uterus) from the guinea pig and in chloralose-anaesthetized, vagotomized cats (arterial blood pressure, heart rate, hindlimb perfusion pressure, and soleus muscle contractility). The results obtained in these experiments indicate that, on a dose basis, dobutamine shows little selectivity in producing alpha-, beta 1-, and beta 2-adrenoceptor-mediated effects. In phentolamine-treated cats, reductions in arterial pressure and total peripheral resistance produced by infusions of dobutamine were little affected by the beta 2-adrenoceptor-selective antagonist butoxamine, but were antagonized by atenolol. The rise in cardiac output produced by dobutamine involved increases in both heart rate and stroke volume. There was little indication of a selective inotropic action, a feature that confirmed the results obtained in isolated atrial preparations. The increase in cardiac output appeared to involve both alpha- and beta-receptor-mediated actions, because phentolamine reduced the rise in cardiac output by reducing stroke volume.
D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000818:Animals; D001262:Atenolol / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D002078:Butoxamine / Q000494:pharmacology; D002302:Cardiac Output / Q000187:drug effects; D002395:Catecholamines / Q000494:pharmacology*; D002396:Catechols; D002415:Cats; D004280:Dobutamine / Q000494:pharmacology*; D005260:Female; D006168:Guinea Pigs; D006339:Heart Rate / Q000187:drug effects; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D009200:Myocardial Contraction / Q000187:drug effects; D010646:Phentolamine / Q000494:pharmacology; D011412:Propanolamines / Q000494:pharmacology; D011943:Receptors, Adrenergic, beta / Q000187:drug effects*; D013318:Stroke Volume / Q000187:drug effects
D000318:Adrenergic beta-Agonists; D002395:Catecholamines; D002396:Catechols; D011412:Propanolamines; D011943:Receptors, Adrenergic, beta; D002078:Butoxamine; D004280:Dobutamine; C026777:ICI 118551; D001262:Atenolol; C018420:Ro 363; D007545:Isoproterenol; D010646:Phentolamine