Effects of verapamil on amylase release from rat pancreatic acini and its relation to calcium fluxes

The effects of verapamil on amylase release and Ca2+ fluxes from rat pancreatic acini have been studied. Verapamil at concentrations above 10 microM dose-dependently inhibited amylase release stimulated by carbachol, but enhanced the amylase release stimulated by cholecystokinin (CCK) and secretin. Verapamil had no significant effect on calcium uptake induced by carbachol or CCK, but significantly inhibited Ca+2 efflux caused by carbachol and slightly increased that caused by CCK. In a Ca2+-free, EDTA-containing medium, the increase in cytoplasmic free Ca2+ caused by carbachol was significantly inhibited by verapamil. Verapamil alone up to 400 microM had no effect on the release of lactic dehydrogenase. In conclusion, the effect of verapamil on amylase release from rat pancreatic acini differs depending on the type of secretagogue used to stimulate amylase release. This effect is not related to blockage of Ca2+ uptake, indicating another mechanism of verapamil on pancreatic acini.