Defensive burying and stress gastric erosions in alcohol-preferring AA and alcohol-avoiding ANA rats

The aim of this study was to investigate differences in shock-prod induced defensive burying and vulnerability to stress gastric ulcerations in two lines of rats selectively bred for alcohol-preference (AA) and alcohol-avoidance (ANA). Alcohol-naïve animals from the AA and ANA lines were tested in the shock-prod defensive burying test and (after an interval of approximately 2 months) in a 75 min water-immersion stress ulceration-inducing procedure. The AA rats showed longer latencies (327.5 s) for burying after shock-prod compared with the ANA animals (128.0 s). Furthermore, the ANA rats developed more stomach ulcerations (12.35 mm) compared with the AA rats (1.30 mm). Animals also differed based on whether they had been tested for defensive burying or not, with the tested animals showing less ulceration development than the control group. We hypothesize that the difference between AA and ANA rats is controlled by some common biochemical mechanism. One likely candidate is the dopaminergic system, which is involved in both the motivational effects of alcohol, as well as anxiety and stomach ulceration. In addition, the alcohol-preferring strain seems to be less fearful and generally may be less sensitive to aversive stimuli, be it shock prod, the aversive properties of alcohol, or water immersion stress.