Pituitary adenylate cyclase activating peptide, a novel VIP-like gut-brain peptide, relaxes the guinea-pig taenia caeci via apamin-sensitive potassium channels

Naunyn Schmiedebergs Arch Pharmacol. 1992 Nov;346(5):511-4. doi: 10.1007/BF00169005.

Abstract

Effects of pituitary adenylate cyclase activating peptide (PACAP-(1-27)) and vasoactive intestinal polypeptide (VIP) on the guinea-pig taenia caeci were studied in the presence of guanethidine and scopolamine. Both peptides (1 nmol/1-1 mumol/l) concentration-dependently relaxed the smooth muscle of the taenia. PACAP-(1-27) and VIP were nearly equipotent. Apamin (30 nmol/l), a selective blocker of calcium-activated potassium channels, abolished the relaxation induced by PACAP-(1-27) whereas the effect of VIP remained unaffected. PACAP-(1-27) may be a candidate for the noncholinergic, non-adrenergic inhibitory neurotransmitter which induces apamin-sensitive relaxation in the intestinal tract.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apamin / pharmacology*
  • Cecum / drug effects
  • Guanethidine / pharmacology
  • Guinea Pigs
  • Hexamethonium Compounds / pharmacology
  • In Vitro Techniques
  • Male
  • Muscle Relaxation / drug effects
  • Muscle, Smooth / drug effects*
  • Neuropeptides / pharmacology*
  • Pituitary Adenylate Cyclase-Activating Polypeptide
  • Potassium Channels / drug effects*
  • Scopolamine / pharmacology
  • Tetrodotoxin / pharmacology
  • Vasoactive Intestinal Peptide / pharmacology

Substances

  • Hexamethonium Compounds
  • Neuropeptides
  • Pituitary Adenylate Cyclase-Activating Polypeptide
  • Potassium Channels
  • Apamin
  • Vasoactive Intestinal Peptide
  • Tetrodotoxin
  • Scopolamine
  • Guanethidine