title: Colokinetic effect of noradrenaline in the spinal defecation center: implication for motility disorders.
abstract: Chronic abdominal pain in irritable bowel syndrome (IBS) usually appears in combination with disturbed bowel habits, but the etiological relationship between these symptoms remains unclear. Noradrenaline is a major neurotransmitter controlling pain sensation in the spinal cord. To test the hypothesis that the descending noradrenergic pathway from the brain stem moderates gut motility, we examined effects of intrathecal application of noradrenaline to the spinal defecation center on colorectal motility. Colorectal intraluminal pressure and expelled volume were recorded in vivo in anesthetized rats. Intrathecal application of noradrenaline into the L6-S1 spinal cord, where the lumbosacral defecation center is located, caused propulsive contractions of the colorectum. Inactivation of spinal neurons by tetrodotoxin blocked the effect of noradrenaline. Pharmacological experiments showed that the effect of noradrenaline is mediated primarily by alpha-1 adrenoceptors. The enhancement of colorectal motility by intrathecal noradrenaline was abolished by severing of the pelvic nerves. Our results demonstrate that noradrenaline acting on sacral parasympathetic preganglionic neurons through alpha-1 adrenoceptors causes propulsive motility of the colorectum in rats. Considering that visceral pain activates the descending inhibitory pathways including noradrenergic neurons, our results provide a rational explanation of the concurrent appearance of chronic abdominal pain and colonic motility disorders in IBS patients.
authors.affiliation: Department of Basic Veterinary Science, Laboratory of Physiology, The United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.
authors.forename: Kiyotada
authors.initials: K
authors.lastname: Naitou
authors.affiliation: Department of Basic Veterinary Science, Laboratory of Physiology, The United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.
authors.forename: Takahiko
authors.initials: T
authors.lastname: Shiina
authors.affiliation: Department of Basic Veterinary Science, Laboratory of Physiology, The United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.
authors.forename: Kurumi
authors.initials: K
authors.lastname: Kato
authors.affiliation: Department of Basic Veterinary Science, Laboratory of Physiology, The United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nakamori
authors.affiliation: Department of Basic Veterinary Science, Laboratory of Physiology, The United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.
authors.forename: Yuuki
authors.initials: Y
authors.lastname: Sano
authors.affiliation: Department of Basic Veterinary Science, Laboratory of Physiology, The United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.
authors.forename: Yasutake
authors.initials: Y
authors.lastname: Shimizu
mesh_terms: D058668:Adrenergic alpha-1 Receptor Antagonists / Q000494:pharmacology; D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage / Q000494:pharmacology; D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D003106:Colon / Q000187:drug effects* / Q000294:innervation / Q000502:physiology; D003672:Defecation / Q000187:drug effects* / Q000502:physiology; D005769:Gastrointestinal Motility / Q000187:drug effects* / Q000502:physiology; D007001:Hypogastric Plexus / Q000503:physiopathology / Q000601:surgery; D007278:Injections, Spinal; D007700:Kinetics; D008161:Lumbosacral Region; D008297:Male; D009638:Norepinephrine / Q000008:administration & dosage / Q000494:pharmacology*; D011224:Prazosin / Q000494:pharmacology; D017207:Rats, Sprague-Dawley; D012007:Rectum / Q000187:drug effects* / Q000294:innervation / Q000502:physiology; D013116:Spinal Cord / Q000187:drug effects* / Q000502:physiology; D013779:Tetrodotoxin / Q000494:pharmacology
chemical_list: D058668:Adrenergic alpha-1 Receptor Antagonists; D000316:Adrenergic alpha-Agonists; D000779:Anesthetics, Local; D013779:Tetrodotoxin; D009638:Norepinephrine; D011224:Prazosin