The ulcerogenic effect of a rest period after exposure to water-restraint stress in rats.

Shock-induced gastric ulceration in rats is exacerbated by allowing animals to rest between the period of stress and sacrifice. Conflicting data have been reported for similar post-stress rest effects using restraint stress. In Experiment 1, rats restrained in water for 2 h and then allowed a 2-h rest period exhibited significantly greater gastric ulceration than rats sacrificed immediately after the 2-h restraint-in-water stress period. The strength of this phenomenon is confirmed by Experiment 2, in which rats challenged with restraint in water for 1.25 h and then allowed a 1.25-h rest period before sacrifice exhibited greater ulceration than animals maintained in the restraint-in-water stress for the full 2 1/2 h. Corticosterone levels for these two treatment groups were similar at the time of sacrifice. Post-stressor rest therefore actively contributes to the ulcerogenic processes initiated by this form of stress challenge.