Vulnerability to stress ulcerogenesis in rats differing in anxiety: a dopaminergic correlate.

Dopamine and its agonists, acting through D1/DA1 receptors, have been shown to be effective protective factors against stress ulcerogenesis. Since anxiety has been related to stress ulcer development, we chose to examine dopaminergic activity in rats screened for the extremes of behaviorally manifest anxiety. High anxious rats develop more stress ulcers and more ethanol ulcers, relative to low anxious animals. High anxious rats require greater amounts of dopaminergic agonists for 50% protection against stress ulcer formation. In conditions of exposure to a stressor, high anxious rats lose amygdalar dopamine at a faster rate than do low anxious rats. These results suggest that anxiety is a significant factor in stress ulcer development and that central dopaminergic function is critically involved in mediating this pathogenetic factor.