On the effect of ageing on the distribution of vasoactive intestinal polypeptide and calcitonin gene-related peptide in the rat brain.

The distribution of calcitonin gene-related peptide (CGRP) and vasoactive intestinal polypeptide (VIP) was investigated by the use of immunohistochemical techniques in the brain of young and aged rats. CGRP-like immunoreactivity (CGRP-LI) showed a significant decrease only in the amygdala, whereas a substantial age-dependent decrease in VIP-like immunoreactivity (VIP-LI) was observed in the cortex, amygdala, substantia nigra, hippocampus and suprachiasmatic nucleus.