Effects of cholinergic and adrenergic agonists on phosphorylation of a 165,000-dalton myofibrillar protein in intact cardiac muscle.

摘要: The purpose of this investigation was to examine the effects beta-adrenergic and muscarinic cholinergic agonists on protein phosphorylation in intact frog atrium. beta-Adrenergic increase decrease 32P incorporation into a 165,000-dalton (165K) within less than 1 min. concentrations isoproterenol that produce increases 165K systolic tension are similar. Further, changes produced by occur with similar time courses. Carbamylcholine decreases somewhat more quickly at lower it incorporation, however. Isoproterenol-stimulated is thought be mediated cAMP-dependent kinase because bath application dibutyryl cAMP, cholera toxin, or phosphodiesterase inhibitors atria. When heart homogenates incubated presence [gamma-32P]ATP, cAMP stimulates protein. cGMP much effective. We suggest carbamylcholine mechanism independent levels inhibits stimulation band 8-bromo cells. Phosphorylation occurs cardiac muscle but not other tissues. hypothesize C-protein, 165K- C-proteins have solubilities associated myofibril. antibodies against bind C-protein purified from rabbit also same region myofibril where found.