[Restoration of the automatic contractile activity of K+-arrested heart muscle cells in culture by means of dibutyryl-3', 5'-adenosine monophosphate].

Cultured myocardial cells of new-born rats which were arrested by 17.6-37.6 mM KCl regained their ability to contract spontaneously after perfusion with 8-10(-4)-4-10(-3) M dibutyryl cyclic AMP. This adrenaline-like action of DbcAMP is compatible with the notion that cyclic AMP is involved as a second messenger in the action of cyclic AMP-raising adrenergic agents on cardiac activity.