A ROLE FOR CALCIUM RELEASE-ACTIVATED CURRENT (CRAC) IN CHOLINERGIC MODULATION OF ELECTRICAL-ACTIVITY IN PANCREATIC BETA-CELLS

S. Bordin and colleagues have proposed that the depolarizing effects o f acetylcholine and other muscarinic agonists on pancreatic beta-cells are mediated by a calcium release-activated current (CRAC). We suppor t this hypothesis with additional data, and present a theoretical mode l which accounts for most known data on muscarinic effects. Additional phenomena, such as the biphasic responses of beta-cells to changes in glucose concentration and the depolarizing effects of the sarco-endop lasmic reticulum calcium ATPase pump poison thapsigargin, are also acc ounted for by our model. The ability of this single hypothesis, that C RAC is present in beta-cells, to explain so many phenomena motivates a more complete characterization of this current.