1. The 1,4-dihydropyridine nucleus serves as the scaffold for important cardiovascular drugs-calcium antagonists-including nifedipine, nitrendipine, amlodipine, and nisoldipine, which exert their antihypertensive and antianginal actions through actions at voltage-gated calcium channels of the CaV1 (L-type) class. 2. These drugs act at a specific receptor site for which defined structure-activity relationships exist, including stereoselectivity. 3. Despite the widespread occurrence of the CaV1 class of channel, the calcium antagonists exhibit significant selectivity of action in the cardiovascular system. This selectivity arises from a number of factors including subtype of channel, state-dependent interactions. pharmacokinetics, and mode of calcium mobilization. 4. The 1,4-dihydropyridine nucleus is also a privileged structure or scaffold that can, when appropriately decorated substituents, interact at diverse receptors and ion channels, including potassium and sodium channels and receptors of the G-protein class.