Pranidipine is the calcium channel blocker. Pranidipine did not affect the sensitivity of the contractile proteins to calcium. Pranidipine also did not alter cyclic GMP-induced relaxation in alpha-toxin-skinned vascular preparations. Pranidipine also prolonged glyceryl trinitrate-induced relaxation in the endothelium denuded rat aorta. Pranidipine enhances cyclic GMP-independent NO-induced relaxation of smooth muscle by a mechanism other than through NO-induced hyperpolarization. These effects were in direct contrast to amlodipine, another new 1,4-dihydropyridine calcium antagonist. Pranidipine increased blood velocity and probably blood flow in the optic nerve head, choroid, and retina of rabbits. Pranidipine was not detrimental to global cardiac function in animals with dilated cardiomyopathy. Pranidipine enhances relaxation produced by endothelium-derived relaxing factor in carotid artery. Pranidipine was investigated as pharmacological agent for the treatment of angina pectoris and hypertension.