Food-anticipatory activity in activity-based anorexia: The involvement of dopamine.

Abstract

Anorexia nervosa (AN) is a severe psychiatric disorder with a high mortality rate. Excessive physical activity and reduced food consumption are commonly described as symptoms of AN. Suppression of hyperactivity by antipsychotics suggest a role of dopamine and serotonin in this trait in AN patients. Activity-based anorexia (ABA) is considered as an animal model for AN. The ABA model consists of scheduled feeding in combination with voluntary wheel running, which results in severe body weight loss and increased physical activity. The hyperactive behavior prior to food access is described as food anticipatory activity. In order to determine the role of dopamine, a dose-response curve of chronic treatment of rats with the non-selective dopaminergic antagonist cis-flupenthixol (ranging from 0.03 to 1.0 mg/day) was determined in the ABA model. Flupenthixol treatment (1.0 mg/day) significantly reduced running wheel activity levels in both ad libitum fed and food-restricted rats. During ABA, flupenthixol-treated rats significantly reduced their body weight loss and increased fat depots, while food intake was not significantly different from vehicle-treated rats. Interestingly, food anticipatory activity still persists in flupenthixol-treated food-restricted rats. These data show that chronic treatment with flupenthixol induces body weight gain in food-restricted rats and reduces running wheel activity levels in ad libitum fed as well as food-restricted rats. We also conclude that blockade of dopamine receptors does not affect food anticipatory activity in ABA rats.