Some psychosomatic causal factors of restraint-in-water stress ulcers.

Rats were stressed by 75 min restraint in a tube suspended vertically while dry (19 degrees C) or partially immersed in tanks of water at different temperatures (19, 27, 35 degrees C), either in a conscious state or while under pentobarbital anesthesia. Restraint was followed by 75 min rest in the home cage and then sacrificed under halothane anesthesia. Assessment of the degree of gastric erosion indicated that restraint alone, whether the animal was rendered unconscious or not, was not sufficient to induce ulceration. However, in conscious animals, the addition of partial immersion did induce ulceration that was inversely related to the temperature of the water bath. This effect was not merely the result of brain stem and spinal reflex processes, because unconscious animals exposed to the most severe conditions (19 degrees C) showed no ulceration.