Chronotropic and inotropic responses to ASL-7022 on isolated rat atria.
ASL-7022 is a new synthetic catecholamine with alpha and beta adrenoceptor stimulating activity having inotropic selectivity in vivo. On the isolated rat atria, ASL-7022 produced concentration-dependent increases in spontaneous rate, developed tension (DT) and maximal velocity of contraction (+T). The maximal chronotropic and inotropic responses to ASL-7022 were similar to those obtained with isoproterenol, although the compound was less potent than isoproterenol. The inotropic and chronotropic effects of ASL-7022 were sensitive to propranolol blockade and were not affected by prazosin blockade. When the inotropic selectivity of ASL-7022 was analyzed, it was found that, like isoproterenol, each concentration of the agonist produced greater chronotropic than inotropic effect. Our results indicate the lack of an alpha 1-mediated component in the chronotropic and inotropic effects of ASL-7022 and the absence of inotropic selectivity in vitro.
Gende
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OA
Centro de Investigaciones Cardiovasculares, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Argentina.
Camilión de Hurtado
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MC
D000818:Animals; D002316:Cardiotonic Agents / Q000494:pharmacology*; D002395:Catecholamines / Q000494:pharmacology*; D055598:Chemical Phenomena; D002621:Chemistry; D004357:Drug Synergism; D005260:Female; D006325:Heart Atria / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects*; D007545:Isoproterenol / Q000494:pharmacology*; D009200:Myocardial Contraction / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains; D013268:Stimulation, Chemical
D002316:Cardiotonic Agents; D002395:Catecholamines; C036054:ASL 7022; D007545:Isoproterenol