Vasoactive intestinal peptide gene expression from embryos to aging rats.

Vasoactive intestinal peptide (VIP) gene transcripts were demonstrated by RNA blot hybridization using VIP-specific RNA hybridization probes. High levels of expression were observed as early as in 16-day-old embryos. In aging rats, the VIP-mRNA levels were reduced significantly (in the cerebral cortex) as compared to 21-day-old rats. Our results suggest a role for the VIP gene protein products during embryonal development. During aging processes the decrease in VIP gene transcripts may be a consequence of either a reduction in the transcriptional activity of VIP neurons or death of VIP-producing cells.