VASOACTIVE INTESTINAL POLYPEPTIDE-AUGMENTED INSULIN RELEASE - ACTIONSON IONIC FLUXES AND ELECTRICAL-ACTIVITY OF MOUSE ISLETS

Vasoactive intestinal polypeptide is a pancreatic neurotransmitter whi ch augments insulin release. To obtain more detailed information on it s mode of action on the pancreatic beta cell we studied the effect of vasoactive intestinal polypeptide on Rb-86+ efflux, Ca-45(2+) uptake, electrical activity and second messenger systems of isolated mouse isl ets. Vasoactive intestinal polypeptide enhanced insulin release and Ca -45(2+) uptake in a concentration-dependent manner, and was effective at non-stimulatory and stimulatory glucose levels. It increased glucos e-induced electrical activity but was without effect on either glucose -mediated changes of Rb-86+ efflux, cAMP or inositol-1,4,5-trisphospha te content. It is suggested that vasoactive intestinal polypeptide aug ments insulin release by increasing the uptake of Ca2+ into the cell b y as yet undefined mechanisms.