Developmental expression of the VIP-gene in brain and intestine.
Vasoactive intestinal peptide (VIP) is a major regulatory peptide in the nervous system, playing a role in normal brain activity. VIP levels change dramatically during postnatal rat brain development, raising the question of how these changes are regulated. To study VIP-gene expression, a sensitive RNA detection assay which uses in vitro-transcribed RNA hybridization probes, corresponding to 4 exons of the VIP-gene, was adapted. Results show that the major VIP-mRNA was 2000-2100 bases long in the rat. The amounts of this RNA varied markedly with development. In the frontal cortex of the rat brain, the 2000-2100-base mRNA increased by at least 5-fold from birth to 3-4 days, showing a maximal content at 14-16 days. VIP-mRNA synthesis therefore apparently precedes peptide synthesis by several days, as VIP in the rat cortex begins to increase only at about 7 days of age. Similarly, in the parietal cortex, VIP-mRNA was detected by 3 days of age. However, the increase in the mRNA content from 3 to 14 days of age was greater than in the frontal cortex, while almost no VIP-mRNA was detected in the newborn rat parietal cortex. In contrast, the hypothalamus and intestine contained significant quantities of VIP-mRNA at birth, the hypothalamic levels in newborns being much higher than anticipated from the peptide levels. In the hippocampus, the major peak in VIP-mRNA content occurred at 8 days of age. Taken together, these results indicate local controls of VIP-gene expression and a developmentally associated role for VIP-gene products. As the VIP-mRNA levels did not always parallel the peptide levels, regulation at the post-transcriptional stage may be essential for normal VIP function.
D000818:Animals; D001921:Brain / Q000254:growth & development / Q000378:metabolism*; D004274:DNA, Recombinant / Q000302:isolation & purification; D007413:Intestinal Mucosa / Q000378:metabolism*; D007422:Intestines / Q000254:growth & development; D009693:Nucleic Acid Hybridization; D011061:Poly A; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism; D012313:RNA; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D014660:Vasoactive Intestinal Peptide / Q000235:genetics / Q000378:metabolism*
D004274:DNA, Recombinant; D011498:Protein Precursors; D012333:RNA, Messenger; D011061:Poly A; D014660:Vasoactive Intestinal Peptide; D012313:RNA