PROLONGED INHIBITION OF VASCULAR CONTRACTION AND CALCIUM INFLUX BY THE NOVEL 1,4-DIHYDROPYRIDINE CALCIUM-ANTAGONIST CINALDIPINE (FRC-8653)

We examined the effects of FRC-8653, a noval dihydropyridine calcium antagonist, on the contraction of an arterial preparation and the calcium influx into vascular smooth muscle cells to clarify the long-lasting hypotensive activity of this drug. Inhibition by FRC-8653 persisted for more than 7 hr after its removal, whereas nifedipine and nicardipine exhibited shorter durations of suppressive activity. These results suggest that prolonged inhibition of calcium influx through L-channels contributes to the long-lasting vasodilative and antihypertensive activity of FRC-8653.