title: Integrative control of rectoanal reflex in guinea pigs through lumbar colonic nerves.
abstract: The aim of the present study was to analyze the neuromodulation of rectoanal reflex activity by lumbar sympathetic nerves in guinea pigs. The mechanical activities of the rectum were recorded with a balloon connected to a pressure transducer, and those of the internal anal sphincter (IAS) were recorded with a custom-made strain gauge force transducer. Gradual and sustained rectal distension evoked the rectoanal reflex, causing cholinergic contractions of the rectum and synchronous nitrergic relaxations of the IAS. Section of the lumbar colonic nerves enhanced both rectal contractions and IAS relaxations. Section of the 13th thoracic cord abolished both rectal contractions and IAS relaxations, but section of the lumbar colonic nerves restored them. Lumbar sympathectomy and pithing sacral cords greatly diminished these rectal contractions and IAS relaxations, but the intrinsic reflex component remained. NG-nitro-L-arginine methyl ester enhanced the intrinsic reflex-mediated contraction of the rectum and abolished reflex-mediated relaxation of the IAS and converted into cholinergic contractions. The present results indicate that the extrinsic lumbar inhibitory outflow causes marked inhibition of the rectoanal reflex via the lumbar colonic nerves.
authors.affiliation: First Department of Surgery, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521, Japan.
authors.forename: Masaya
authors.initials: M
authors.lastname: Yamanouchi
authors.forename: Hidehiko
authors.initials: H
authors.lastname: Shimatani
authors.forename: Makoto
authors.initials: M
authors.lastname: Kadowaki
authors.forename: Satoshi
authors.initials: S
authors.lastname: Yoneda
authors.forename: Tadashi
authors.initials: T
authors.lastname: Nakagawa
authors.forename: Hisao
authors.initials: H
authors.lastname: Fujii
authors.forename: Miyako
authors.initials: M
authors.lastname: Takaki
mesh_terms: D001003:Anal Canal / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D002404:Catheterization; D003106:Colon / Q000294:innervation*; D003655:Decerebrate State; D003714:Denervation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006168:Guinea Pigs; D008161:Lumbosacral Region; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D009126:Muscle Relaxation / Q000187:drug effects / Q000502:physiology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D012007:Rectum / Q000187:drug effects / Q000502:physiology*; D012018:Reflex / Q000502:physiology*; D013116:Spinal Cord; D013562:Sympathectomy; D013564:Sympathetic Nervous System / Q000502:physiology*; D013904:Thoracic Vertebrae
chemical_list: D004791:Enzyme Inhibitors; D019331:NG-Nitroarginine Methyl Ester