ABSTRACT
The maximal endothelial dependent relaxation of isolated aortic rings to cumulative doses of acetylcholine was significantly decreased in the Cyclosporine-A (CSA, 20 mg kg(-1) day(-1)) treated animals compared to olive oil (CSA vehicle) treated control. Administration of antihypertensive drugs like diltiazem, enalapril or propranolol to CSA treated animals augmented the endothelial damage induced by CSA. These drugs also increased the bioavailability of CSA. However, administration of losartan to CSA treated animals produced a significant increase in endothelial dependent relaxation as compared to CSA treated control but did not affect the bioavailability of CSA significantly. The results suggest that losartan is safer compared to other antihypertensives for the treatment of CSA induced hypertension.