Cholinergic and nitrergic regulation of in vivo giant migrating contractions in rat colon

Mona Li, Christopher P. Johnson, Mark B. Adams, Sushil K. Sarna

Research output: Contribution to journalArticle

68 Scopus citations

Abstract

The aim of this study was to characterize in vivo rat colonic motor activity in normal and inflamed states and determine its neural regulation. Circular muscle contractions were recorded by surgically implanted strain-gauge transducers. The rat colon exhibited predominantly giant migrating contractions (GMCs) whose frequency decreased distally. Only a small percentage of these GMCs propagated in the distal direction; the rest occurred randomly. Phasic contractions were present, but their amplitude was very small compared with that of GMCs. Inflammation induced by oral administration of dextran sodium sulfate suppressed the frequency of GMCs in the proximal and middle but not in the distal colon. Frequency of GMCs was suppressed by intra-peritoneally administered atropine and 4-diphenylacetoxy-N-methyl-piperidine methiodide and was enhanced by Nw-nitro-L-arginine methyl ester. Serotonin, tachykinin, and calcitonin gene-related peptide receptor or receptor subtype antagonists as well as guanethidine and suramin had no significant effect on the frequency of GMCs. Verapamil transiently suppressed the GMCs. In conclusion, unlike the canine and human colons, the rat colon exhibits frequent GMCs and their frequency is suppressed in inflammation. In vivo GMCs are stimulated by neural release of acetylcholine that acts on M3 receptors. Constitutive release of nitric oxide may partially suppress their frequency.

Original languageEnglish (US)
Pages (from-to)G544-G552
JournalAmerican Journal of Physiology - Gastrointestinal and Liver Physiology
Volume283
Issue number3 46-3
DOIs
StatePublished - Sep 2002

Keywords

  • Diarrhea
  • Enteric neurons
  • Inflammation
  • Peristaltic reflex

ASJC Scopus subject areas

  • Physiology
  • Hepatology
  • Gastroenterology
  • Physiology (medical)

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