Interstitial cells of Cajal are involved in the afferent limb of the rectoanal inhibitory reflex

• Published in: Gut Vol. 54; no. 8; pp. 1107 - 1113
• Main Authors: de Lorijn, F, de Jonge, W J, Wedel, T, Vanderwinden, J M, Benninga, M A, Boeckxstaens, G E
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd and British Society of Gastroenterology 01.08.2005; BMJ; BMJ Publishing Group LTD; Copyright 2005 by Gut
• Subjects: 5′-adenosine triphosphate; Anal Canal - cytology; Anal Canal - innervation; Anal Canal - physiology; anal sphincter; Animals; anorectal manometry; Arginine; ATP; Biological and medical sciences; Colon; Colonic Motility; Distension; Electrical stimuli; Enzyme Inhibitors - pharmacology; Esophagus; Gastroenterology; Gastroenterology. Liver. Pancreas. Abdomen; IAS; ICC; Immunohistochemistry - methods; Innervation; internal anal sphincter; Interstitial cells; Interstitial cells of Cajal; L-NAME; Laboratory animals; LOS; lower oesophageal sphincter; Manometry - methods; Medical sciences; Mice; Mice, Inbred C57BL; Mice, Inbred Strains; Motility; Muscle contraction; Muscle, Smooth - physiology; Mutation; N-nitro-L-arginine methyl ester; NANC; Nerve Tissue Proteins - metabolism; Neural networks; neuronal nitric oxide synthase; Neurotransmission; NG-Nitroarginine Methyl Ester - pharmacology; NHS; Nitric oxide; Nitric Oxide - physiology; Nitric Oxide Synthase - metabolism; Nitric Oxide Synthase Type I; Nitric-oxide synthase; nNOS; non-adrenergic non-cholinergic; normal horse serum; Organ Culture Techniques - methods; RAIR; rectoanal inhibitory reflex; Rectum; Rectum - physiology; Reflex - physiology; Rodents; Sensory neurons; SNP; sodium nitroprusside; Sphincter; Studies; Synaptic Transmission - physiology; TBS-TX; Transgenic animals; Tris buffered saline-Triton X; United States > US; California; Interstitial cell; Anus; Arginine; Esophageal sphincter; Aminoacid; Limb; Cajal cell; Gastroenterology; Pylorus; Rectum; Anal sphincter
• ISSN: 0017-5749; 1468-3288; 1458-3288
• DOI: 10.1136/gut.2004.051045

Background and aims: Interstitial cells of Cajal (ICC) have been shown to be involved in nitrergic neurotransmission of the lower oesophageal sphincter and pylorus. Here we studied the role of ICC and nitric oxide (NO) in the inhibitory neurotransmission of the murine internal anal sphincter (IAS). Methods: The rectoanal inhibitory reflex, rectal compliance, and relaxation of the isolated IAS to electrical stimulation were measured in controls, KIT W/KIT Wv mice, and neuronal NO synthase (nNOS) deficient mice. In addition, we evaluated the effect of blockade of nNOS using N-nitro-L-arginine methyl ester. Distribution of nNOS positive neurones and ICC in the IAS was assessed immunohistochemically. Results: KIT positive ICC were present in a dense network in the IAS of controls but not in KIT W/KITWv mice. Relaxation of IAS muscle strips induced by electrical stimulation was diminished in nNOS−/− mice but not in KIT W/KIT Wv mice. Blockade of NOS reduced the relaxation of IAS muscle strips in both mice. Relaxation of the IAS to rectal distension was significantly diminished in KIT W/KIT Wv mice and nNOS deficient mice. In concert, in vivo blockade of NOS attenuated the relaxation of the IAS in controls. No significant difference in compliance was found. Conclusion: The inhibitory innervation of the IAS and the rectoanal inhibitory reflex are mediated by NO and the rectoanal inhibitory reflex requires an intact network of ICC in the IAS. Thus both loss of nitrergic innervation and deficiency of ICC lead to impaired anal relaxation and may play an important role in rectal evacuation disorders.