Long term administration of some antipsychotic drugs increases body weight and feeding in rats. Are D2 dopamine receptors involved?

Long term administration of the antipsychotic drugs thioridazine, trifluoperazine, haloperidol, and sulpiride increased body weight in rats. This effect was found to be sex dependent, that is, while female rats were prone to gain weight, male rats did not. Chlorpromazine and fluphenazine decreased body weight in male rats but did not affect females. The mechanism of body weight gain was investigated with sulpiride. A linear relationship between dose of sulpiride and body weight gain was found. Also, sulpiride increased caloric intake, and both actions were counteracted by bromocriptine, a specific D2 receptor agonist. These results confirm that antipsychotic drugs affect feeding and body weight and suggest that hyperphagia and body weight gain might be mediated by blockade of dopamine receptors of the D2 type.