CHANGES IN ENDOTHELIUM-DEPENDENT RELAXATION AND LEVELS OF CYCLIC-NUCLEOTIDES IN THE PERFUSED MESENTERIC ARTERIAL BED FROM STREPTOZOTOCIN-INDUCED DIABETIC RATS

The influence of diabetes on the function of vascular endothelium was examined with respect to the role of nitric oxide (NO) in the regulati on of blood pressure (BP) in vivo, the vascular relaxation, and levels of cAMP and cGMP in the effluent of the perfused mesenteric arterial bed from streptozotocin-induced diabetic rats. An intravenous injectio n of 100 mg/kg N(omega)-nitro-L-arginine methylester (L-NAME) caused h ypertension in both diabetic rats and controls, However, the degree of hypertension in the diabetic rats was significantly lower than that i n the controls. Acetylcholine (ACh)-induced vasorelaxation of the perf used mesenteric arterial bed decreased in diabetic rats. At the same t ime, the levels of cAMP and cGMP in the effluent of the diabetic rats were also lower than in the controls. These data indicate that NO form ation is involved in the regulation of BP in rats, and is decreased in diabetic rats, due to an impairment of the vascular endothelium, incl uding the endothelium of resistance vessels.