title: PAC1 receptor-mediated relaxation of longitudinal muscle of the mouse proximal colon.
abstract: Since pituitary adenylate cyclase-activating polypeptide (PACAP) was shown to partially mediate nonadrenergic, noncholinergic (NANC) relaxation of longitudinal muscle of the proximal colon of ICR mice, we further studied the receptor subtype activated by PACAP by using a mutant mouse whose PAC1 receptors are markedly reduced. In wild-type mice, the PACAP-mediated component of NANC relaxation was 33%, but it was absent in the mutant mice. The potency of exogenous PACAP in inducing relaxation in the mutant mice was one hundredth of that in wild-type mice. VPAC1 and VPAC2 receptors were not suggested to have any role in the relaxation. These results suggest that PACAP mediates NANC relaxation of longitudinal muscle of mouse proximal colon via PAC1 receptors.
authors.affiliation: Department of Veterinary Pharmacology, Graduate School of Agriculture and Life Sciences, Osaka Prefecture University, Sakai, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Mukai
authors.forename: Yuji
authors.initials: Y
authors.lastname: Satoh
authors.forename: Akikazu
authors.initials: A
authors.lastname: Fujita
authors.forename: Tadayoshi
authors.initials: T
authors.lastname: Takeuchi
authors.forename: Norihito
authors.initials: N
authors.lastname: Shintani
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Hashimoto
authors.forename: Akemichi
authors.initials: A
authors.lastname: Baba
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Hata
mesh_terms: D000818:Animals; D003106:Colon / Q000187:drug effects / Q000502:physiology*; D005260:Female; D008297:Male; D051379:Mice; D008817:Mice, Mutant Strains; D009126:Muscle Relaxation / Q000187:drug effects / Q000502:physiology*; D009132:Muscles / Q000187:drug effects / Q000378:metabolism; D009479:Neuropeptides / Q000378:metabolism*; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D051237:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I; D011979:Receptors, Pituitary Hormone / Q000819:agonists / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D051239:Receptors, Vasoactive Intestinal Peptide, Type II; D051238:Receptors, Vasoactive Intestinal Polypeptide, Type I
chemical_list: C495402:Adcyap1 protein, mouse; C495504:Adcyap1r1 protein, mouse; D009479:Neuropeptides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D051237:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I; D011979:Receptors, Pituitary Hormone; D051239:Receptors, Vasoactive Intestinal Peptide, Type II; D051238:Receptors, Vasoactive Intestinal Polypeptide, Type I; C495507:Vipr1 protein, mouse; C495510:Vipr2 protein, mouse