Prior stress and susceptibility to stress ulcer.

Rats were exposed to daily sessions of either restraint plus cold, forced exercise, or grid shock for one month and then subjected to the ulcerogenic effects of either supine restraint plus cold, or activity-stress. Chronic stress generally protected against stress ulcer but the protection depended on the degree of similarity between the pre-treatment stressor and the ulcerogenic procedure. Pre-treatment with restraint plus cold provided protection which applied not only to supine restraint plus cold but also generalized to activity-stress. Foot-shock pre-treatment did not significantly reduce restraint ulcer but it significantly exacerbated activity-stress ulcer.