Failure of Leiurus quinquestriatus venom to affect potassium movements in pancreatic islets

The venom from the Israeli scorpion Leiurus quinquestriatus failed to affect 86Rb and 45Ca outflow from rat pancreatic islets perifused in the presence of tetrodotoxin and stimulated by the Ca2+-ionophore A23187 or the hypoglycaemic sulfonylurea tolbutamide. In non-stimulated islets, the venom components whose effects are insensitive to tetrodotoxin did not affect 45Ca and 86Rb outflow. Last, the venom did not alter 86Rb inflow. These findings suggest that 86Rb, 45Ca fluxes and more specifically the Ca2+-activated K+ permeability in the pancreatic B-cell are insensitive to the venom.