A mibefradil metabolite is a potent intracellular blocker of L-type Ca(2+) currents in pancreatic beta-cells.

It has been shown that mibefradil (Ro 40-5967) exerts a selective inhibitory effect on T-type Ca(2+) currents, although at higher concentrations it can antagonize high voltage-activated Ca(2+) currents. The action of mibefradil on Ca(2+) channels is use- and steady-state-dependent and the binding site of mibefradil on L-type Ca(2+) channels is different from that of dihydropyridines. By using conventional whole-cell and perforated patch-clamp...