A small amount of wheel running facilitates eating in nondeprived rats.
A high level of dopaminergic activation such as that produced by a high dose of amphetamine suppresses eating, whereas a low level such as that produced by a low dose can have the opposite effect. Like a high dose of amphetamine, a high level of wheel running also suppresses eating. It was hypothesized that this suppression is due to dopaminergic activation produced by wheel running. If so, a relatively small amount of wheel running should produce a low level of dopaminergic activation and thus have the same effect as a low dose of amphetamine: facilitation of eating. In the present experiment, nondeprived rats were allowed to run in a wheel for 30 min before a feeding test. As predicted, a little wheel running facilitated eating in these rats relative to appropriate controls. The present results may be relevant to an understanding of eating disorders in humans.