Activity in the circular alley does not produce the activity anorexia syndrome in rats

Abstract

The activity anorexia syndrome is characterized by reduced food intake and body weight compared to control levels and increasing levels of physical activity. To induce it, food-restricted rats are confined in running wheels except during the daily meal. We tested whether activity in a flat circular alley also produces the activity anorexia syndrome. In Experiment 1, food-restricted rats were maintained in alleys, wheels, or home cages (control condition). In Experiment 2, they were maintained in alleys, wheels, novel cages, or home cages. The novel cage was added to control for the possibility that the alley might produce an anorectic effect simply because it was a new living space. The alley did not produce the activity anorexia syndrome whereas the wheel did. Although weight loss was greater in the alley than home-cage condition, the alley produced weak, inconsistent suppression of feeding. Moreover, the suppression produced by the alley may have stemmed simply from living in a novel environment. Finally, in contrast to wheel running, alley activity decreased over days. Alley activity, unlike wheel running, may not be reinforcing. Likely, a physical activity must be reinforcing to produce the activity anorexia syndrome. Implications for anorexia nervosa were discussed.