Endothelium-dependent vascular responses: effect of hypertension and cyclosporin A.

Through the release of endothelium-derived relaxing and contracting factors, the endothelium can profoundly affect local vascular tone. In hypertension and during chronic cyclosporin A therapy, morphological changes of the endothelium develop. Recent studies in isolated arteries have demonstrated that endothelium-dependent relaxations induced by a variety of substances are decreased in acute and chronic hypertension and during cyclosporin A therapy. A reduced vascular smooth muscle responsiveness to endothelium-derived relaxing factor, the release of a cyclooxygenase-dependent endothelium-derived contracting factor in some animal models of hypertension, and possibly a decreased release of EDRF under some conditions may contribute to these functional alterations. In hypertension and during cyclosporin. A therapy, functional changes of the endothelium may contribute to increased peripheral vascular resistance and to vascular damage occurring under these conditions.