Food and water intake, meal patterns and activity of obese and lean Zucker rats following chronic and acute treatment with delta9-tetrahydrocannabinol.

A series of experiments investigated the effects of delta9-THC on food and water intakes and wheel-running activity of Zucker rats. Following chronic drug treatment (15 days), food and water intakes of all rats were suppressed, but intakes and body weights of the obese rats recovered more slowly than those of lean rats. Acute effects of the drug (24 hr) were examined using techniques of meal pattern analysis and were discussed in relation to known patterns of anorectic drug action. The drug-induced anorexia was both delayed and of short duration, with no rebound eating observed for either solid or liquid diets. Both feeding rate and meal size were reduced, but meal frequency was transiently increased. The time of onset of the first meal remained unchanged. The time course of the suppression of feeding was paralleled by a suppression in running-wheel activity. These findings suggest that the drug-induced reduction in food and water intake may be the result of a decreased level of arousal.