Changes of neuropeptide concentrations in the brain following experimentally induced mononeuropathy in Wistar Kyoto and spontaneously hypertensive rats.

The effect of unilateral, experimentally induced, mononeuropathy on concentrations of neuropeptide Y (NPY), neurokinin A (NKA), substance P (SP), calcitonin gene-related peptide CGRP) and galanin- (GAL-) like immunoreactivities (-LI) was studied in Wistar Kyoto (WKY) and spontaneously hypertensive (SHR) rat brains. Two weeks following ligation of the sciatic nerve, significantly higher concentrations of NPY-LI were found in the hippocampus, striatum and occipital cortex of both rat strains. CGRP-LI and GAL-LI were increased in the hippocampus of WKY rats. NKA-LI and SP-LI were decreased to different degrees in the pituitary of the WKY and SHR rats, indicating that the changes of the tachykinins, CGRP and GAL were selectively associated with the basal level of sympathetic tone. The increased concentrations of NPY-LI in the brain, not influenced by sympathetic tone, may be part of a general defense reaction in response to trauma.