title: Pituitary adenylate cyclase activating polypeptide-27 (PACAP-27) inhibits pentagastrin-stimulated gastric acid secretion in conscious rats.
abstract: Pituitary adenylate cyclase activating polypeptide (PACAP) is a novel neuropeptide and has two amidated forms, PACAP-27 and PACAP-38. Its chemical structure is similar to that of vasoactive intestinal peptide (VIP). In our previous studies, we found that PACAP has a stimulatory effect on rat exocrine pancreas secretion and an inhibitory effect on rat gastrointestinal motility. These effects of PACAP-27 were greater than those of PACAP-38 and VIP. In the present study, we examined the effect of PACAP-27 on basal and pentagastrin (PG)-stimulated gastric acid secretion in conscious rats and compared its effect with that of VIP. Rats were equipped with a chronic gastric fistula and a permanent IV line and separately housed in metabolic cages. The effects of PACAP-27 and VIP at doses of 1.25, 2.5, 5 and 10 nmol/kg/h on basal and PG (24 micrograms/kg/h)-stimulated gastric acid secretion were tested. Our results showed that: (1) VIP had no significant effect on basal and PG-stimulated gastric acid secretion at the tested doses. (2) PACAP-27 had no effect on basal acid secretion but had a dose-dependent inhibitory effect on PG-stimulated gastric acid secretion. The highest inhibition by PACAP-27, 68.2 + 8.1%, was achieved at 5 nmol/kg/h. We suggest that PACAP may have a regulatory role in gastric acid secretion.
authors.affiliation: Department of Medicine, Tulane University School of Medicine, New Orleans, LA 70112.
authors.forename: Z
authors.initials: Z
authors.lastname: Mungan
authors.forename: V
authors.initials: V
authors.lastname: Ozmen
authors.forename: A
authors.initials: A
authors.lastname: Ertan
authors.forename: A
authors.initials: A
authors.lastname: Arimura
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D005744:Gastric Acid / Q000378:metabolism*; D008297:Male; D009479:Neuropeptides / Q000494:pharmacology*; D010418:Pentagastrin / Q000494:pharmacology*; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D051381:Rats; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology
chemical_list: C495403:Adcyap1 protein, rat; D009479:Neuropeptides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D014660:Vasoactive Intestinal Peptide; D010418:Pentagastrin