Lacidipine Prevents Endothelial Dysfunction in Salt-Loaded Stroke-Prone Hypertensive Rats

Endothelium-dependent vasorelaxation is defective in hypertensive rats, especially in conduit arteries. In the stroke-prone spontaneously hypertensive rat, impaired endothelium-dependent vasorelaxation appears to contribute to the pathogenesis of stroke independent of blood pressure. Because treatment with lacidipine, a long-acting calcium channel blocker, protects against stroke and cardiovascular remodeling in this model, we investigated the effect of this treatment on endothelium-dependent vasorelaxation in the aorta. Stroke-prone rats were exposed to a salt-rich diet (1% NaCl in drinking water) with or without lacidipine (1 mg. kg(-1). d(-1)) for 6 weeks. A high-sodium diet (1) increased systolic blood pressure, aortic weight, and wall thickness and plasma renin activity (P<0.05); (2) markedly reduced nitric oxide (NO)-mediated, endothelium-dependent relaxation of aortic rings to acetylcholine and the sensitivity to the relaxing effect of S-nitroso-N-acetylpenicillamine, an NO donor (P<0.001); and (3) induced an elevation of preproendothelin-1 mRNA levels in aortic tissue (P<0.01) without affecting endothelial NO synthase mRNA levels. Lacidipine treatment prevented the salt-dependent functional and structural alterations of the aorta, including the overexpression of the preproendothelin-1 gene, and increased endothelial NO synthase mRNA levels in aortic tissue (P<0.01). In conclusion, lacidipine protects stroke-prone hypertensive rats against the impairment of endothelium-dependent vasorelaxation evoked by a salt-rich diet, and this effect may contribute to its beneficial effect against end-organ damage and stroke.