An economic analysis of alcoholic and nonalcoholic beer drinking in rats exposed to daily restraint stress or handling

Abstract

Using a behavioral economic approach, this study attempted to determine whether the reinforcing strength of alcoholic or nonalcoholic beer changes after stress or handling. Twenty‐four, male Wistar rats were trained to bar press for either alcoholic or nonalcoholic beer and assigned to one of four treatment groups: stress‐alcohol (SA), no stress‐alcohol (NA), stress‐no alcohol (SN) and no stress‐no alcohol (NN). The stressed condition consisted of 15 min of restraint stress, while non‐stressed rats were handled and placed into a novel cage for 15 min immediately prior to the session. After training under an FR1 schedule, the schedule was increased every five sessions from 3 to 32 in logarithmic steps. Consumption was plotted as a function of ratio size and modeled by the exponential‐demand equation (Hursh & Silberberg 2008). Consumption prior to the stress/handling manipulation was greater for nonalcoholic than alcoholic beer, but there was no difference between stressed and unstressed rats for either solution. When stress was applied, alcohol consumption decreased relative to that in the non‐stressed rats. Stress did not have an effect on non‐alcoholic drinking. The economic analysis showed that NA, SN and NN groups all defended beer consumption with greater vigor than the SA group. Our results suggest that stress has a suppressive effect on alcohol drinking in "naïve" rats.This work was supported by the Mellon Foundation.