Impairment of endothelium-dependent relaxation in aortae from spontaneously diabetic rats

1. Diabetes mellitus is known to produce alterations in vascular reactivity. The present study examined the effects of endothelium-dependent and endothelium-independent relaxing substances on thoracic aorta from control and spontaneously diabetic rats. 2. Endothelium-dependent relaxation produced by acetylcholine or the calcium ionophore, A23187, in aortic rings precontracted with phenylephrine was significantly attenuated in diabetic vessels. 3. Relaxations produced by sodium nitroprusside or adenosine in diabetic preparations were comparable to those in control vessels. 4. The results show that diabetes leads to a specific impairment of endothelial-dependent relaxation.