The impact of low to moderate chronic intermittent ethanol exposure on behavioral endpoints in aged, adult, and adolescent rats.

The average age of the population in the United States and other countries is increasing. Understanding the health consequences in the aged population is critical. Elderly individuals consume ethanol, often at elevated rates, and in some cases in a binge episode. The present study sought to investigate whether binge-like ethanol exposure in aged male rats produced differential health and behavioral effects compared to adult male and adolescent male rats. Subjects were exposed to either 1.0 g/kg or 2.0 g/kg ethanol every other day via intraperitoneal injection for 20 days, and tested on a variety of behavioral measures and body weight. Binge-like ethanol exposure produced differential effects on body weight between aged and adolescent and adult rats. In addition, aged rats had a significantly longer loss of righting reflex and demonstrated a trend toward tolerance following the 2.0-g/kg exposure. No significant effects on anxiety-like behavior as measured by open arm entries, depressive-like symptoms as measured by immobility in the forced swim test, or cognitive performance as measured by latency and path length in the Morris water maze were found. These results demonstrate that aged animals are differentially sensitive to the impact of chronic intermittent ethanol exposure in some, but not all behaviors. Future research is needed to understand the mechanisms of these differential effects.