Alterations in vasoactive intestinal polypeptide-related peptides after pentylenetetrazole-induced seizures in rat brain.
The possible involvement of vasoactive intestinal polypeptide-related peptides in pentylenetetrazol (PTZ)-induced seizures in rats was investigated. The chemoconvulsant PTZ was administered (45 mg/kg i.p.) either acutely or chronically for three days. The detailed time course of changes in VIP-(1-28) and VIP-(22-28) was examined in several rat brain areas 5 and 20 min and 24 h after acute treatment and after three days chronic treatment. Ir-VIP levels dramatically decreased in all areas 5 min after PTZ injection, remained low after 20 min and progressively increased back to control values after 24 h and after three days of repeated treatment (except for the cortex). Chromatographic analysis of extracts prepared from PTZ-treated rats revealed a concomitant decrease in VIP-(1-28) and increase in VIP-(22-28). Thus VIP-(22-28) might be a product of the internal cleavage of the precursor VIP-(1-28) after its neuronal release; alternatively, VIP-(22-28) might be generated by post-transcriptional processing of VIP-(1-28), and thus be an 'independent' neuropeptide. The results suggest that VIP-(1-28)/VIP-(22-28)-containing neurons might be involved in PTZ-induced seizures in rat brain, and that VIP-(22-28) might play a role in these experimental seizures.
Romualdi
P
P
Department of Pharmacology, University of Bologna, Italy.
Lesa
G
G
Donatini
A
A
Balboni
G
G
Tomatis
R
R
Ferri
S
S
D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D004827:Epilepsy / Q000139:chemically induced / Q000378:metabolism*; D007274:Injections, Intraperitoneal; D008297:Male; D008969:Molecular Sequence Data; D010433:Pentylenetetrazole / Q000008:administration & dosage / Q000494:pharmacology; D010446:Peptide Fragments / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism*
D010446:Peptide Fragments; D014660:Vasoactive Intestinal Peptide; C061058:vasoactive intestinal peptide (22-28); D010433:Pentylenetetrazole