WATER IMMERSION-RESTRAINT STRESS INDUCES EXPRESSION OF IMMEDIATE-EARLY GENES IN GASTROINTESTINAL-TRACT OF RATS

The aims of this study were to determine 1) which cells are involved i n stress-induced acute gastric mucosal lesion and 2) what kinds of mol ecular alterations are induced by stress, using immediate-early genes (IEG) as tools for detection of cellular activation. Male Wistar rats were exposed to acute water immersion-restraint stress. Protein and mR NA for IEG were detected by immunohistochemistry and in situ hybridiza tion, respectively. This stress induced the expression of c-fos and ne rve growth factor-induced gene (NGFI-A) mRNA in gastric epithelial cel ls, the smooth muscle layer of small blood vessels, and the stomach wa ll. Stress upregulated the mRNA levels of these IEG in the duodenal ep ithelial cells and induced de novo expression of IEG in the smooth mus cle layer of small blood vessels and the duodenal wall. These findings indicate that these cells are activated in response to stress. Expres sion of these IEG and/or transcriptional factors may reflect an initia tion of mechanisms for repairing the lesions induced by stress as well as an adaptation to the stress.