Cyclic nucleotides and cardiac function.

Abstract
Effects of cyclic[c]AMP and cGMP on cardiac function were investigated in dogs, rabbits, frogs, guinea pigs and embryonic chick hearts. Through the action of catecholamines and by adenylate cyclase conversion, cyclic nucleotides are proposed to exhibit a positive inotropic action, to alter myocardial membrane K+ and Ca2+ movement and to increase glycogenolysis. Effects of metabolic drugs, theophylline, papaverine and tetrodotoxin are described.