Does Exercise Ameliorate the Effects of Early Life Stress on Drug Reward?

Laurel Pritchard, Ph.D. (University of Nevada, Las Vegas)

A history of childhood abuse, neglect or other psychological trauma significantly elevates risk for substance use and abuse, even when other risk factors are controlled. Research in our lab is aimed at determining how such early life stressors alter neural circuits that mediate behavioral responses to psychostimulant drugs, particularly amphetamines and cocaine. For this line of research, we use a rodent model of early life stress, termed maternal separation, in which neonatal rats are repeatedly separated from their mothers.

We have already used this model to examine the effects of early life stress on behavioral responses to d-amphetamine, and we are currently completing similar studies with methamphetamine. These studies include measures of drug-induced locomotor activity and reinforcement, as well as analysis of addiction-related gene expression in the brains of maternally-separated and control rats. Because men and women differ in their vulnerability to psychostimulant abuse, we are also interested in examining sex differences in the maternal separation model.

We have recently initiated a project to determine whether specific interventions might reverse or ameliorate the effects of early life stress on psychostimulant sensitivity. In our initial experiments, we will use voluntary exercise on a running wheel, a manipulation that has been shown to counteract the effects of stress on a variety of neural systems. The results of these experiments could have important implications for simple, low-cost interventions to prevent substance abuse for individuals at high risk due to a history of childhood abuse, neglect or trauma.