Effects of oxygen radicals and radical scavenging on opossum lower esophageal sphincter

L. S. Leichus, R. M. Thomas, J. A. Murray, J. L. Conklin

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

Nitric oxide mediates esophageal peristalsis and lower esophageal sphincter (LES) relaxation. Superoxide produced with inflammation inactivates nitric oxide. Superoxide is cleared in biological systems by superoxide dismutase. We tested the hypothesis that superoxide and the superoxide scavenging system modulate LES function. Transverse strips of muscle from the opossum LES relaxed when stimulated by an electrical field. Diethyldithiocarbamite was used to inhibit copper/zinc superoxide dismutase. Xanthine and xanthine oxidase were used to generate superoxide. Xanthine with xanthine oxidase or diethyldithiocarbamite alone had no effect on the LES. However, xanthine/xanthine oxidase and diethyldithiocarbamite reduced LES relaxation 34.1% and increased its resting tone 71.2%. Superoxide dismutase did not affect LES function, but protected the tissue from the effects of diethyldithiocarbamite and xanthine/xanthine oxidase. These studies are consistent with the hypothesis that superoxide acts by inactivating nitric oxide and suggest that these antioxidant enzyme systems may play a role in the maintenance of LES function.

Original languageEnglish (US)
Pages (from-to)592-596
Number of pages5
JournalDigestive diseases and sciences
Volume42
Issue number3
DOIs
StatePublished - Apr 16 1997

Keywords

  • enteric nervous system
  • esophageal motility
  • esophagus
  • nitric oxide
  • smooth muscle
  • superoxide
  • superoxide dismutase

ASJC Scopus subject areas

  • Physiology
  • Gastroenterology

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