Changes in vascular reactivity in rats with experimental renal insufficiency.

In ureter-ligated rats, the pressor effects of both norepinephrine and angiotensin II i.v. on systemic blood pressure and serum sodium concentration were significantly decreased when compared with those in control rats, while serum potassium concentration, blood urea nitrogen, mean systemic blood pressure and plasma renin activity were significantly increased. The microscopic examination of aortic smooth muscles did not show significant histological lesions in the tissues obtained from ureter-ligated rat. The responsiveness of aortic strips isolated from ureter-ligated rats to norepinephrine and angiotensin II was significantly decreased in comparison with that from control rats. The results suggest that a decreased pressor response to norepinephrine and angiotensin II under ureter-ligated conditions may be attributed to a decrease in vascular reactivity to drugs.