Pituitary adenylate cyclase activating polypeptide-27 (PACAP-27) inhibits pentagastrin-stimulated gastric acid secretion in conscious rats

Regul Pept. 1992 Apr 9;38(3):199-206. doi: 10.1016/0167-0115(92)90102-z.


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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Dose-Response Relationship, Drug
  • Gastric Acid / metabolism*
  • Male
  • Neuropeptides / pharmacology*
  • Pentagastrin / pharmacology*
  • Pituitary Adenylate Cyclase-Activating Polypeptide
  • Rats
  • Vasoactive Intestinal Peptide / pharmacology


  • Adcyap1 protein, rat
  • Neuropeptides
  • Pituitary Adenylate Cyclase-Activating Polypeptide
  • Vasoactive Intestinal Peptide
  • Pentagastrin