title: Mediators of nonadrenergic, noncholinergic relaxation in longitudinal muscle of the intestine of ICR mice.
abstract: Mediators of nonadrenergic, noncholinergic (NANC) relaxation in longitudinal muscle of several regions of ICR mouse intestine were studied. An inhibitor of synthesis of nitric oxide, N(G)-nitro-L-arginine (L-NOARG) at 10 microM significantly inhibited NANC relaxations induced by electrical field stimulation (EFS) in the jejunum, ileum, and the proximal and distal colon. Especially in the ileum extent of the inhibition was more than 80%. An antagonist of vasoactive intestinal peptide (VIP) receptors, VIP(10-28) at 3 microM partially inhibited the EFS induced relaxations in the jejunum and proximal colon, but very slightly in the distal colon and had no effect in the ileum. An antagonist of pituitary adenylate cyclase activating peptide (PACAP) receptor, PACAP(6-38) at 3 microM partially inhibited the EFS-induced relaxations in the proximal and distal colon, but not in the jejunum and ileum. Totals of the percentages of relaxant components mediated by nitric oxide, VIP and PACAP in every region are roughly equal to a hundred percent. In another series of experiments, EFS-induced relaxations were almost completely inhibited by the treatment of the segments with L-NOARG and VIP(10-28) in the jejunum, with L-NOARG, VIP(10-28) and PACAP(6-38) in the proximal colon, and with L NOARG and PACAP(6-38) in the distal colon. The present results suggest that nitric oxide solely mediates the relaxation of longitudinal muscle of the ileum of ICR mice, whereas nitric oxide and VIP co-mediate it in the jejunum, nitric oxide, VIP and PACAP in the proximal colon, and nitric oxide and PACAP in the distal colon.
authors.affiliation: Department of Medical Technology, Osaka Prefectural College of Health Sciences, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Satoh
authors.forename: T
authors.initials: T
authors.lastname: Takeuchi
authors.forename: Y
authors.initials: Y
authors.lastname: Yamazaki
authors.forename: Y
authors.initials: Y
authors.lastname: Okishio
authors.forename: H
authors.initials: H
authors.lastname: Nishio
authors.forename: K
authors.initials: K
authors.lastname: Takatsuji
authors.forename: F
authors.initials: F
authors.lastname: Hata
mesh_terms: D000818:Animals; D003106:Colon / Q000737:chemistry / Q000294:innervation / Q000502:physiology; D004558:Electric Stimulation; D004594:Electrophysiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007082:Ileum / Q000737:chemistry / Q000294:innervation / Q000502:physiology; D007422:Intestines / Q000737:chemistry / Q000294:innervation / Q000502:physiology*; D007583:Jejunum / Q000737:chemistry / Q000294:innervation / Q000502:physiology; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009126:Muscle Relaxation / Q000187:drug effects / Q000502:physiology*; D009130:Muscle, Smooth / Q000294:innervation / Q000502:physiology*; D009479:Neuropeptides / Q000037:antagonists & inhibitors / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D019335:Nitroarginine / Q000494:pharmacology; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D011941:Receptors, Adrenergic; D011950:Receptors, Cholinergic; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D011979:Receptors, Pituitary Hormone / Q000502:physiology; D018005:Receptors, Vasoactive Intestinal Peptide / Q000502:physiology; D014660:Vasoactive Intestinal Peptide / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: C495402:Adcyap1 protein, mouse; D004791:Enzyme Inhibitors; D009479:Neuropeptides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D011941:Receptors, Adrenergic; D011950:Receptors, Cholinergic; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D011979:Receptors, Pituitary Hormone; D018005:Receptors, Vasoactive Intestinal Peptide; D019335:Nitroarginine; D009569:Nitric Oxide; D014660:Vasoactive Intestinal Peptide