Neurons in the Medulla Oblongata Related to Gastric Mucosal Lesion of Rats Subjected to Restraint Water-Immersion Stress

OBJECTIVE: Restraint water-immersion stress (RWIS) can induce a gastric mucosal lesion. Our objective was to detect the phenotype of activated neurons in the medulla oblongata of rats subjected to RWIS. STUDY DESIGN: Male Wistar rats were divided into 2 groups in accordance with the duration of RWIS: a control group and the RWIS group. The brain sections were treated with a dual immunohistochemistry of Fos and choline acetyltransferase (ChAT) or tyrosine hydroxylase (TH) or oxytocin receptor (OTR) or vasopressin 1b receptor (V1bR) or methionine-enkephalin (M-ENK). RESULTS: Compared to the control group, the number of Fos+ ChAT-immunoreactivity (IR) neurons in the dorsal motor nucleus of the vagus (DMV) and nucleus ambiguous (NA) and that of Fos+ TH-IR neurons in the nucleus of the solitary tract (NTS) were evidently increased in the RWIS group; meanwhile, more OTR-IR and V1bR-IR neurons in the DMV and NTS were activated. A few M-ENK-IR perikarya were observed only in the NTS, with no difference between the RWIS and control groups. CONCLUSION: Data suggest that the hyperactivity of cholinergic neurons in the DMV and NA and catechol-amine neurons in the NTS is one of the main mechanisms of gastric mucosal lesions induced by RWIS; the OT-sensitive and AVP-sensitive neurons, excepting M-ENK ones, are involved in the modulation of the gastric mucosal lesion during RWIS.