Structural Model for Dihydropyridine Binding to L-type Calcium Channels*

1,4-Dihydropyridines (DHPs) constitute a major class of ligands for L-type Ca(2+) channels (LTCC). The DHPs have a boat-like, six-membered ring with an NH group at the stern, an aromatic moiety at the bow, and substituents at the port and starboard sides. Various DHPs exhibit antagonistic or agonistic activities, which were previously explained as stabilization or destabilization, respectively, of the closed activation gate by the portside …