The effect of the autonomic nervous system on cell proliferation of the gastric mucosa in stress ulcer formation.

The role of the autonomic nervous system in cell proliferation of the gastric mucosa during restraint water immersion stress was investigated utilizing the spontaneously hypertensive rat (SHR) and its progenitor, the Wistar-Kyoto rat (WKY). Three hours of water-immersion restraint induced gastric lesions more frequently in WKY than in SHR, although there were few visual lesions in either strain in two hours of stress. The number of 5-bromo-2'-deoxyuridine (BrdU) positive cells in the corpus ventriculi mucosa markedly decreased in the WKY, but did not change in the SHR after two hours of water-immersion restraint stress. The acetylcholine content in the mucosa significantly decreased and the density of acetylcholinesterase (ACh-E) containing fiber of mucosa remarkably increased in only WKY after two hours stress exposure. On the other hand, there was no significant difference in either the responsiveness or the content of norepinephrine and epinephrine, which indicates sympathetic nervous function, after stress exposure in WKY and SHR. Similarly, the response of serum gastrin was not significantly different between the two strains. These results strongly suggest that the parasympathetic nerve plays an essential role in cell proliferation of the gastric mucosa in the pathogenesis of stress ulcer.