Cibenzoline, an ATP-sensitive K~+ channel blocker, binds to the K~+ -binding site from the cytoplasmic side of gastric H~+, K~+, -ATPase

摘要

Cibenzoline,(±)-2-(2,2-diphenylcyclopropyl-2-imidazoline succinate, has been clinically used as one of the Class I type antiarrhythmic agents and also reported to block ATP-ensitive K~+ channels in excised membranes from heart and pancreaticβcells. In the present study, we investigated if this drug inhibited gastric H~+, K~+ -ATPase activity in vitro. Cibenzoline inhibited H~+, K~+ -ATPase activity of permeabilized leaky hog gastric vesicles in a Concentration-dependent manner(IC_50: 201μM), whereas no effect was shown on Na~+, K~+ -ATPase Activity of dog kidney(IC_50: > 1000μM).