The block of the expressed L-type calcium channel is modulated by the β3 subunit

Abstract

The α 1C subunit of the L-type calcium channel was stable, expressed alone or in combination with the β 3 subunit in Chinese hamster ovary cells. The β 3 subunit enhanced significantly the inactivation of barium currents indicating that both subunits interacted with each other. The β 3 subunit decreased signinicantly the half-maximal inhibitory concentration of the calcium channel blockers (−)-gallopamil and verapamil, but did not affect significantly the block caused by isradipine and mibefradil at the holding potentials of −80 mV and −40 mV. These results suggest that the β 3 subunit affects distinctly the interaction of the expressed α 1c subunit with different classes of organic calcium channel blockers.