[Calcium antagonists. Great tissue selectivity is the basis of their therapeutic use]

Calcium antagonists are established drugs for the treatment of a number of cardiovascular disorders. A specific subtype of voltage-sensitive calcium channel (the L-channel) is the target of all these drugs. The main subgroups of calcium antagonists (phenylalkylamines, benzothiazepines and dihydropyridines) differ in their binding sites on the L-channel, and are characterised by differences in their selectivity of action vis-a-vis vascular smooth muscle and the cardiac conduction system. At a molecular level, each subgroup of calcium antagonists is unique in its mechanism of action, though individual dihydropyridines also differ from each other in this respect. The structure, function and distribution of L-channels, as well as the molecular basis of the unique tissue selectivity of calcium antagonists are described in the article, and the question of serious side-effects is also discussed.