Activators of voltage‐dependent L‐type calcium channels

The L class of voltage‐dependent Ca 2+ channels provides an important pathway for Ca 2+ entry into a variety of excitable cells. Many drugs have been shown to be blockers of this channel including the clinically available nifedipine, verapamil, and diltiazem. An increasing number of compounds are now being recognized as activators of L‐type Ca 2+ channels. The best characterized of these are certain 1,4‐dihydropyridines, typified by Bay K 8644, which act as partial agonists of the channel. The benzoylpyrrole group of molecules, which includes FPL 64176, have proven to be highly efficacious L channel agonists. Certain naturally occurring substances, ranging from toxins to endogenous ligands, have also been proposed as activators of this channel. Activators of L‐type Ca 2+ channels have proven to be valuable tools with which to study the structure and function of these channels and could lead to the development of new therapeutic entities.