Impaired acetylcholine- and nitroglycerin-induced vascular relaxation in cyclosporine-treated rats

Cyclosporine treatment has been reported to induce chronic elevation of blood pressure and endothelial damage. The mechanism by which this occurs is not known. To assess the effect of cyclosporine treatment on alpha-adrenergic vasoconstriction and endothelium-dependent and -independent vascular relaxation, we administered rats (n is 10) 40mg/kg/day cyclosporine or placebo (n is 10). After 8 weeks aortic rings were mounted in oxygenated Krebs buffer for the recording of isometric tension. The rings were precontracted with 0.1 uM phenylephrine (Phe) and relaxed with selective concentrations of acetylcholine (Ach) and nitroglycerin (TNG). In cyclosporine-treated rats, alpha-adrenergic vasoconstriction is enhanced, and endothelium-dependent as well as endotheliumindependent vascular relaxation are depressed.