Novel Environment Exploration of HiS and LoS Rats after Ethanol Consumption

Abstract

The behavioral and emotional effects of ethanol consumption in High Saccharin and Low Saccharin rats were the object of this study. Initially drinking alcohol is associated with an elevation of mood and euphoria, which are components of positive reinforcement. However, once alcohol-seeking behavior has been established, periods of withdrawal are marked by feelings of craving and discomfort. Because saccharin intake is a phenotype that correlates positively with ethanol intake and inversely with emotional reactivity, 24 HiS and 23 LoS rats were randomly assigned one of three groups: A control group which remained na?ve to ethanol; a chronic group which received 2 weeks of forced ethanol; and a withdrawal group which received 2 weeks of forced ethanol, and a 48 hour withdrawal period. An open field apparatus was used not only to record and measure a rat?s willingness to explore a potentially dangerous environment, but also their novel object seeking behavior. Startle responses to auditory stimuli were also measured in a startle amplitude test. Differences in the measures of open field locomotor activity and exploration were observed. The biggest difference in latency to enter the center was seen in the ethanol exposed groups, particularly between the LoS withdrawal group and the LoS chronic group. Startle amplitudes from this experiment are consistent with previous findings that rat strains with low voluntary alcohol consumption generally score higher on measures of emotionality. Among LoS rats, those withdrawn from ethanol startled more than the chronic and na?ve rats.