Vascular effects of calcium antagonists. Uses in some cerebrovascular disorders.

1. Smooth muscle contraction is related to the intracellular free Ca2+ concentration. 2. Potential dependent Ca2+ channels (PDCs) are generally more sensitive to Ca2+-antagonists (CAts) than receptor-operated Ca2+ channels (ROCs). However, there exists a wide variation in the sensitivity of ROCs and CAts, which largely depends on the vessel studied. 3. Cerebral and coronary arteries seem to be very sensitive to CAts. 4. New dihydropyridines possess selectivity for the cerebrovascular bed. 5. The vasospasm subsequent to subarachnoid hemorrhage appears to be sensitive to CAts. 6. CAts prevent or reduce the neurologic alterations elicited by cerebral ischemia, and some of them induce beneficial effects in the prophylaxis of migraine.