Quinapril Attenuates the Effect of Long-Term L-NAME Administration on the Vascular Reactivity of Diabetic Rats

Angiotensin-converting enzyme (ACE) inhibitors including quinapril could exert a protective effect on cardiovascular system through endothelial system in normoglycemic and diabetic rats. The present experimental work was designed to study the vascular reactivity of aortic ring segments isolated from streptozotocin (STZ)-diabetic rats treated for 4 weeks with nitro-L-arginine-methyl ester (L-NAME 50 mg/100 ml) or L-NAME plus quinapril (10 mg/100 ml) in drinking water. The results showed that quinapril treatment significantly attenuated the augmented contractile response to phenylephrine and KCl in diabetic rats. In addition, quinapril treatment partially restored the reduced contractile response in diabetic animals treated chronically with L-NAME. It can be concluded that quinapril could partly counteract the effect of long-term L-NAME administration on vascular reactivity in STZ-diabetic rats