Changes in Inhibitory Control of Circular Smooth Muscle During Coilitis in the Rat

Abstract

Colitis causes symptoms of diarrhea interspersed with periods of quiescence. Changes in smooth muscle contractility may contribute to abnormal motility seen in inflammatory bowel disease. Inhibitory neurotransmitters contribute a significant role in maintaining normal motility and may be altered during inflammation. The aim of this study was to compare inhibitory mechanisms of normal (CONTROL) with inflamed animals. Male Sprague-Dawley rats received intrarectal saline (CONTROL) or trinitrobenzenesulfonic acid in 50% ethanol. The distal colon was removed after 4 hours (ACUTE) or 28 days + 4 hours after saline (HEALED) or trinitrobenzenesulfonic acid (REINFLAMED). In circular smooth muscle, concentration-dependent responses to potassium and acetylcholine as well as to substance P and neurokinin A were determined in the presence of antagonists (atropine, NG-nitro-L-arginine, aminoguanidine, apamin, tetrodotoxin, and hexamethonium). Spontaneous contractions were determined in the presence of nitric oxide synthase inhibitors, NG-nitro-L-arginineand aminoguanidine. The amplitude of spontaneous contractions was significantly (p < 0.05) increased from CONTROL (1529 +- 337 mN/cm2) in ACUTE (6755 +- 1004 mN/cm2) and REINFLAMED (6705 +- 2526 mN/cm2), while frequency was increased from CONTROL (9 +- 2 contractions/10 seconds) in HEALED (27 +- 4 contractions/10 seconds) and REINFLAMED (27 +- 6 contractions/10 seconds). Responses to acetylcholine, substance P, and neurokinin A in HEALED and REINFLAMED were not significantly different from CONTROL. Responses to tachykinins were similar also in the presence of hexamethonium, NG-nitro-L-arginine + apamin, and NG-nitro-L-arginine + atropine. In contrast, acute inflammation significantly increased ( p< 0.05) the response to substance P and acetylcholine, but decreased ( p < 0.05) the response to neurokinin A.

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Document Details

Document Type
Technical Report
Publication Date
Mar 25, 1998
Accession Number
AD1011764

Entities

People

  • Carol A. Bossone

Organizations

  • Uniformed Services University of the Health Sciences

Tags

DTIC Thesaurus Topics

  • Animals
  • Autonomic Nervous System
  • Brain
  • Cell Physiological Processes
  • Cells
  • Data Storage Systems
  • Enteric Nervous System
  • Gastroenteritis
  • Gastrointestinal Tract
  • Human Behavior
  • Inflammation
  • Membrane Potentials
  • Muscle Cells
  • Nervous System
  • Peptides
  • Physiology
  • Rodents

Fields of Study

  • Medicine

Readers

  • Cardiovascular Physiology