VIP suppression in the intestine and cerebral cortex following administration of VIP antiserum to newborn rats.

The administration of vasoactive intestinal peptide (VIP) antiserum to newborn rats significantly reduced the VIP content, both in the cerebral cortex and in intestinal epithelial cells. The decrease was observed at postnatal days 14 and 21 and also in 90 day-old animals. The neonatal treatment produced a significant increase in the density of high- and low-affinity binding sites for VIP in the cerebral cortex at post-natal days 14 and 21 whereas in the intestinal epithelial cells only the low-affinity binding sites were up-regulated at the same time points. VIP suppression induced by neonatal administration of the corresponding antiserum may represent a useful approach to further characterize the physiological role of this neuropeptide.