"Calcium Influx Blockers" and Vascular Smooth Muscle: Do We Really Understand the Mechanisms?

Excerpt

We are no longer referring to the new large class of cardiovascular drugs as "calcium antagonists" (1). These drugs do not act according to the traditional concepts of an agonist-antagonist relationship. Rather, the large heterogeneous group of drugs that lower intracellular calcium ion concentration are now called "calcium influx blockers" or "slow-channel blockers" or "inhibitors of the slow calcium current." Such a classification rests on the ability of these agents to inhibit the slow calcium influx that occurs during the plateau of the action potential (phase 2) after depolarization of cardiac tissue (2). By contrast, drugs that alter the "fast