Regulation of protein secretion and metabolism in rat salivary glands. Effects of norepinephrine and carbachol on the glycogenolysis in submaxillary glands.

Carbachol and norepinephrine induce glycogen breakdown in rat submaxillary glands incubated in vitro. These effects are suppressed by specific inhibitors of cholinergic receptors (atropine, a muscarinic blocker) and of adrenergic receptors (propranolol, a beta-blocker and phentolamine, an alpha-blocker). The beta-adrenergic effect seems to be mediated through the adenosine 3':5'-monophosphate system, whereas the alpha-adrenergic and cholinergic effects are dependent of Ca2+ influx into cell. In the two latter systems, it is suggested that a direct activation of phosphorylase b kinase by calcium takes place. These data clearly indicate that glycogenolysis in rat submaxillary glands in vitro can be independently affected by sympathetic and parasympathetic agents via specific receptors.