TY - JOUR
T1 - Pituitary adenylate cyclase-activating polypeptide relaxes rat gastrointestinal smooth muscle
AU - Mungan, Z.
AU - Arimura, A.
AU - Ertan, A.
AU - Rossowski, W. J.
AU - Coy, D. H.
N1 - Funding Information:
This study was supported in part by NIH grants DK-09094 and DK-30167, a grant from Takeda Chemical Industries, Ltd, and Gastroenterology Section Research Fund 530569. The authors thank Dr. Janet C. Rice for her help with statistical analysis and Lisa M. Baylor and Sebnem C. Salt for their ‘excellent technical assistance.
PY - 1992
Y1 - 1992
N2 - Pituitary adenylate cyclase-activating polypeptide (PACAP) is a new member of the secretin/glucagon peptides family, being most homologous to vasoactive intestinal peptide (VIP). The present study was designed to investigate a possible effect of PACAP on the rat gastrointestinal smooth muscle in vitro. We demonstrated that 1) PACAP reduced basal smooth-muscle contractions in all portions of the gastrointestinal tract, but the effect of VIP was region-specific. The inhibitory effect of PACAP in mid-colon was approximately 100 times greater than that of VIP. 2) PACAP significantly inhibited smooth-muscle contractions induced by acetylcholine or carbachol. The inhibitory effect of PACAP was not affected by hexamethonium and was additive to the inhibitory effect of atropine and pirenzepine. 3) PACAP inhibited smooth-muscle contractions induced by substance P, cholecystokinin, and galanin, even after atropine treatment. Although the exact mechanism of the inhibitory action of PACAP remains to be clarified, PACAP appears to exert its effect in the rat at a site other than muscarinic receptors, probably through a direct effect on gastrointestinal smooth muscle in vitro.
AB - Pituitary adenylate cyclase-activating polypeptide (PACAP) is a new member of the secretin/glucagon peptides family, being most homologous to vasoactive intestinal peptide (VIP). The present study was designed to investigate a possible effect of PACAP on the rat gastrointestinal smooth muscle in vitro. We demonstrated that 1) PACAP reduced basal smooth-muscle contractions in all portions of the gastrointestinal tract, but the effect of VIP was region-specific. The inhibitory effect of PACAP in mid-colon was approximately 100 times greater than that of VIP. 2) PACAP significantly inhibited smooth-muscle contractions induced by acetylcholine or carbachol. The inhibitory effect of PACAP was not affected by hexamethonium and was additive to the inhibitory effect of atropine and pirenzepine. 3) PACAP inhibited smooth-muscle contractions induced by substance P, cholecystokinin, and galanin, even after atropine treatment. Although the exact mechanism of the inhibitory action of PACAP remains to be clarified, PACAP appears to exert its effect in the rat at a site other than muscarinic receptors, probably through a direct effect on gastrointestinal smooth muscle in vitro.
KW - Pituitary adenylate cyclase-activating polypeptide
KW - Rat GI tract
KW - Smooth-muscle contraction
KW - Vasoactive intestinal polypeptide
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U2 - 10.3109/00365529209000091
DO - 10.3109/00365529209000091
M3 - Article
C2 - 1529272
AN - SCOPUS:0026740747
SN - 0036-5521
VL - 27
SP - 375
EP - 380
JO - Scandinavian Journal of Gastroenterology
JF - Scandinavian Journal of Gastroenterology
IS - 5
ER -