Differential effects of 8-bromo-cyclic GMP on the basal contractile force and beta-adrenoceptor-mediated positive inotropic action in the canine atrium.
8-Bromo-cyclic GMP caused a negative inotropic action on the canine atrial muscle, whilst it did not affect the positive inotropic action of phenylephrine mediated via beta-adrenoceptors. These findings are in line with the hypothesis that the muscarinic receptor stimulation may exert functional changes in the heart via two different intracellular biochemical processes: one involving cyclic AMP and the other involving cyclic GMP. 8-Bromo-cyclic GMP mimics the latter but not the former mechanism in canine atria.
D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000818:Animals; D016275:Atrial Function; D002316:Cardiotonic Agents / Q000494:pharmacology*; D006152:Cyclic GMP / Q000031:analogs & derivatives* / Q000502:physiology; D004285:Dogs; D009200:Myocardial Contraction
D000318:Adrenergic beta-Agonists; D002316:Cardiotonic Agents; C016276:8-bromocyclic GMP; D006152:Cyclic GMP