Noradrenergic innervation of the superior mesenteric artery in streptozotocin-diabetic rats.

Abstract

The noradrenergic innervation of the superior mesenteric artery of control and 6- or 40-week streptozotocin-diabetic rats was examined by assaying tissue norepinephrine levels and by using the glyoxylic acid histofluorescence technique associated with quantitative image analysis. Short-term (6-week) experimental diabetes had no significant effect on norepinephrine levels nor on the density of the network of fluorescent nerve fibers that supply the superior mesenteric artery. Long-term (40-week) experimental diabetes was accompanied by a significant reduction of norepinephrine content of the superior mesenteric artery and by an impaired morphology of the perivascular plexus of fluorescent nerve fibers. The present study suggests that long-term streptozotocin diabetes in the rat may be accompanied by neuropathy of the noradrenergic nerves that supply the superior mesenteric artery. The results are discussed in relation to the possibility that, at least in part, the impairment of cardiovascular functions described in human diabetes may depend on alterations of the noradrenergic innervation of blood vessels.