Effects of adrenaline and noradrenaline on glucose-induced electrical activity of mouse pancreatic beta cell.

The effects of adrenaline and noradrenaline on membrane potential and glucose-induced electrical activity were studied in micro-dissected mouse Islets of Langerhans. Both catecholamines induced hyperpolarization and blocked electrical activity in the presence of 11.1 mM glucose. Phentolamine, but not propranalol, blocked these effects, indicating predominantly alpha receptor action. Quinine, but not tetraethylammonium ions, antagonized the inhibitory effects of the catecholamines. The data are consistent with the hypothesis that alpha receptor activation induces a transient increase in intracellular Ca2+ concentration which in turn leads to an increase in K+ permeability.