Abstract

The purpose of this study was to examine the effects of the aggression and social dominance on stress ulcer in isolated mice. Subjects were ICR strain of mice that were separated from their own litters on the 21st day of life and reared in isolation and in group for 150 days. All animals divided into four groups, "no-aggressiveness", "low-aggressiveness", "middle-aggressiveness" or "high-aggressiveness" on the basis of the frequency of aggressive behaviors to the stimulating animals. Twenty-four hours after aggression rating, animals were exposed to cold-restraint stress for an hour, and then stomach ulcer was estimated under operational microscope. The results were as follows: First, Ulcer scores of "low-aggressiveness" and "high-aggressiveness" group were lower than group rearing animals. Second, "no-aggressiveness" and "middle-aggressiveness" group were not different from group animals in ulcer score. Third, Ulcer scores in "middle-aggressiveness" group were higher than another three isolation groups. The results of this study hold similar views that if the reaction of emotion is suppressed, physical diseases tend to happen or if unpleasure feeling such as anger does not vent, various psychosomatic diseases such as stomach ulcer or hypertension can be induced.