Effect of nitrendipine on cardiac and renal lesions and arterial hypertrophy. Protective effect of a low dose of calcium antagonist in deoxycorticosterone-induced hypertensive rats.

A low dose of nitrendipine (1 mg/kg twice daily) ameliorated the percent incidence and severity of vascular lesions in the kidney and heart induced by deoxycorticosterone (DOC). Less protection was offered by administration of 1 mg/kg of the calcium antagonist once daily. A lower dose of the antagonist (0.5 mg/kg) administered twice daily produced almost no protection against myocardial scars, but the percent incidence and severity of renal tubular casts and glomerular changes were similar to those following injection of 1 mg/kg of the antagonist twice daily. DOC induced hypertrophy of the media in aorta, coronary artery and renal interlobular artery and renal arteriole. Neither 1 mg/kg once or twice daily nor 0.5 mg twice daily of calcium antagonist modified the hypertrophy of the arterial vasculature in the hypertensive DOC group. We conclude that a low dose of the calcium antagonist dissociates at least in part lesions but not hypertrophy from the increased systolic blood pressure, because the antagonist protects against vascular lesions induced by the hypertension. The antagonist likely acts on the endothelial cell of the vessels alone or combined with an effect on the vascular smooth muscle cells.