SELECTIVE DAMAGE TO SENSORIMOTOR PERIVASCULAR NERVES IN THE MESENTERIC VESSELS OF DIABETIC RATS

The perivascular innervation of the superior mesenteric artery and vei n was examined using immunohistochemical and immunoassay techniques in rats 8 weeks after induction of diabetes with streptozotocin (STZ). I ncreased density of innervation and fluorescence intensity was noted f or substance P- and calcitonin gene-related peptide-immunoreactive ner ves in the diabetic vessels. A slight increase in the density of vasoa ctive intestinal polypeptide-immunoreactive nerve fibers innervating t he mesenteric artery tvas also noted. However, there was no change in the density of neuropeptide Y- and dopamine beta-hydroxylase-immunorea ctive nerve fibers, although the fluorescence intensity of neuropeptid e Y-immunoreactive nerve fibers was reduced in diabetic rat vessels. I mmunoassays showed that the levels of substance P- and calcitonin gene -related peptide were increased >10-fold in the diabetic mesenteric ve in, while levels of neuropeptide Y and vasoactive intestinal polypepti de were unchanged. In summary, there is a marked increase in nerve fib ers containing sensory neuropeptides in mesenteric vessels of STZ-indu ced diabetic rats, which, in view of the reported impaired sensorimoto r function in these vessels, is likely to reflect a neuropathic change .