EFFECT OF N-G-NITRO-L-ARGININE METHYL-ESTER AND L-ARGININE ON ETHANOL-INDUCED GASTRIC-MUCOSAL DAMAGE IN NEWBORN RATS

Previous studies have suggested that the mechanisms involved in gastri c mucosal protection in newborn rats are different from those in adult rats. The aim of this study was to derermine whether nitric oxide (NO ) has protective effects against ethanol-induced gastric mucosal damag e in newborn rats. In 1-week-old rats, (1) pretreatment with N-G-nitro -L-arginie methyl ester (L-NAME), a NO synthase inhibitor, increased g astric mucosal damage induced by 35% ethanol dose-dependently (0.3 - 3 0 mg/kg), (2) concurrent administration of 300 mg/kg L-arginine (L-Arg ) inhibited the L-NAME induced-in crease in damage completely, and (3) pretreatment with low dose L-Arg (30 mg/kg) decreased the mucosal dam age induced by 60% ethanol. We concluded that endogeneous NO is involu ved in the protective mechanism of the gastric mucosa in neonatal rats .