Cellular mechanism of atrial natriuretic factor secretion by cultured rat cardiocytes

Using primary culture of atrial cardiocytes from neonatal rats, we have demonstrated that alpha 1-adrenergic and muscarinic cholinergic agonists have a direct stimulatory effect on secretion of atrial natriuretic factor (ANF) and that ANF secretion is stimulated by phorbol ester, Ca2+ ionophore, high K+-induced depolarization and Ca2+-channel agonists. These data suggest that receptor-mediated mobilization of intracellular Ca2+ and activation of protein kinase C as well as Ca2+ influx via voltage-dependent Ca2+ channels are involved in the secretory mechanism of ANF.