Stress selectively reduces sugar + saccharin mixture intake but increases proportion of calories consumed as sugar by rats

Abstract

Exposure to unsignaled, inescapable tailshock reduces intake of quinine- or saccharin-adulterated water but increases intake of dilute sucrose solution. This pattern suggests that stress may reduce consumption of quinine and saccharin by enhancing their aversive taste properties. The present study provided additional support for this interpretation: Stress reduced intake of a saccharin-adulterated solution of glucose (Experiment 1) or sucrose (Experiment 2) but not of unadulterated sugar solutions. Stress also reduced body weight and total calorie intake, and increased selection of calories in the form of sugar (Experiment 2). These findings are inconsistent with the generalized “anhedonia” concept prominent in the literature on stress-induced changes in ingestion and other motivated behaviors. The selectivity of tailshock’s effects on ingestion encourages further development of an energy-regulation model of stress (the regulatory shift hypothesis), including exploration of the roles that macronutrient accessibility and sugars’ stress-reducing, reinforcing properties might play in the behavior of stressed rats.