Pituitary adenylate cyclase activating peptide, a novel VIP-like gut-brain peptide, relaxes the guinea-pig taenia caeci via apamin-sensitive potassium channels.
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.
Schwörer
H
H
Department of Medicine, University of Göttingen, Federal Republic of Germany.
Katsoulis
S
S
Creutzfeldt
W
W
Schmidt
W E
WE
D000818:Animals; D001030:Apamin / Q000494:pharmacology*; D002432:Cecum / Q000187:drug effects; D006145:Guanethidine / Q000494:pharmacology; D006168:Guinea Pigs; D006584:Hexamethonium Compounds / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D009479:Neuropeptides / Q000494:pharmacology*; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D015221:Potassium Channels / Q000187:drug effects*; D012601:Scopolamine / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology
D006584:Hexamethonium Compounds; D009479:Neuropeptides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D015221:Potassium Channels; D001030:Apamin; D014660:Vasoactive Intestinal Peptide; D013779:Tetrodotoxin; D012601:Scopolamine; D006145:Guanethidine