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Mibefradil, A T-type calcium channel antagonist in Y1 cells
M Esneu1, N Gallo-Payet, M D Payet
1Department of Physiology and Biophysics, Faculty of Medicine, University of Sherbrooke, Quebec, Canada.
Abstract:
The effect of mibefradil, a new nondihydropyridine Ca2+ channel antagonist, was investigated on Y1 cells which exhibited T-and L-type Ca2+ currents. In the great majority of these cells, mibefradil rapidly and selectively blocked T-type Ca2+ current in a dose-dependent manner with a half maximum action at 10-7 M. Furthermore, the specific L-type Ca2+ channel inhibitor, nifedipine, blocked the Ca2+ inward current remaining after the action of mibefradil. Mibefradil does not modify the voltage-dependent characteristics of the current/voltage relationship. However, mibefradil is more effective at depolarized membrane potential.