Eating caused by neuropeptide-Y injection in the paraventricular hypothalamus: response to (+)-fenfluramine and (+)-amphetamine in rats

(+)-Fenfluramine and (+)-amphetamine have been compared for their ability to reduce food intake in food-deprived rats or eating caused by injecting neuropeptide-Y in the paraventricular hypothalamus of free feeding rats. (+)-Fenfluramine at doses ranging from 0.625 to 5 mg kg-1 reduced eating caused by neuropeptide-Y more effectively than it did the food intake of food-deprived rats, whereas (+)-amphetamine (dose range 0.625-2.5 mg kg-1) reduced both types of eating to a similar extent. The results confirm that (+)-fenfluramine, although less potent than (+)-amphetamine in reducing eating by food-deprived rats, markedly reduces overeating caused by various endogenous substances or stress in free feeding rats. The physiological significance of the neuropeptide-Y-induced eating and its control by (+)-fenfluramine remains to be elucidated.