nitroarginine and Esophagitis

The present study explores the effects of nitric oxide synthase inhibitor on esophageal motility in a feline model with esophagitis. Perfusion of the esophagus with acid produced inflammatory changes of esophageal mucosa. The esophageal motility was measured before and after the perfusion. One group of cats was given nitric oxide inhibitor orally at the same time as the perfusion of acid. The control group was given water instead. Esophagitis impairs the motility of the esophagus. However, the esophageal motility of the cats that were given nitric oxide synthase inhibitor decreased less than that of the control group. The results suggested that during esophagitis there is an alteration of the nitric oxide synthase/nitric oxide pathway in the esophagus, which may be one of the important mechanisms of esophageal motility dysfunction.

Topics: Animals; Cats; Enzyme Inhibitors; Esophagitis; Esophagogastric Junction; Gastrointestinal Motility; Hydrochloric Acid; Male; Models, Animal; Nitric Oxide Synthase; Nitroarginine

It has been suggested that free radicals are involved in esophagitis. To study the role and potential interaction of superoxide anion and nitric oxide (NO) in low-grade esophagitis, we perfused acidified pepsin (30 min every 12 hr) for seven days in rabbits treated with different agents to modulate the generation of these radicals. Measurements included macroscopic and microscopic damage, superoxide anion generation, mucosal nitric oxide synthase activity, and peroxynitrite formation. Low-grade esophagitis was associated with increased nitric oxide synthase mucosal activity and mucosal damage was dose-dependently increased by treatment with the NO synthase inhibitor NG-nitro-L-arginine. Superoxide anion was scarcely generated in the mucosa, but this was not accompanied by any change in the activity of mucosal superoxide dismutase. Treatment with superoxide dismutase did not improve mucosal damage. Generation of peroxynitrites was not detected. In conclusion, nitric oxide is involved in the mucosal defense of the esophagus against acid- and pepsin-induced damage. Superoxide anion generation seems irrelevant in the induction of low-grade esophagitis and not sufficient to interact with nitric oxide to generate measurable mucosal peroxynitrite radicals.

Topics: Animals; Enzyme Inhibitors; Esophagitis; Esophagus; Free Radicals; Mucous Membrane; Nitrates; Nitric Oxide; Nitric Oxide Synthase; Nitroarginine; Nitroprusside; Oxidants; Pepsin A; Rabbits; Superoxide Dismutase; Superoxides