Inhibitions of feeding examined in rhesus monkeys with hypothalamic disconnexions.
In rhesus monkeys with knife cuts which disconnected the ventromedial hypothalamus and produced hypothalamic hyperphagia, we have studied a variety of stimuli known to reduce food intake: weight gain, emotionally arousing stimuli, bitter-tasting food, amphetamine, and pre-prandial intragastric infusion of nutrient. We demonstrate that these animals are similar to animals with ventromedial lesions in passing through a "dynamic" phase of overeating and weight gain and then stabilizing their body weight at a new level by reducing their feeding in a "static" phase. These animals are also more sensitive to the inhibitory effects of noise and bad taste in food. They, however, are less sensitive to the anorexic action of amphetamine. These results suggest that the ventromedial region is not crucial for the inhibitions produced by emotional arousal under our experimental conditions, but plays some role in amphetamine anorexia. Amphetamine is likely to have some specific anorexic action beyond its potential for arousal, since the same animals which are sensitive to the inhibitory effects of arousal are also resistant to amphetamine. Finally these hyperphagic animals do not differ from intact controls in the reduction of food intake produced by preloading with intragastric nutrient. This result is not consistent with the concepts that hypothalamic hyperphagia is caused by a disruption of satiety and that the ventromedial hypothalmic region is a crucial "satiety" centre.
D000661:Amphetamine / Q000494:pharmacology; D000818:Animals; D001835:Body Weight; D001931:Brain Mapping; D004777:Environment; D005247:Feeding Behavior / Q000187:drug effects / Q000502:physiology*; D000882:Haplorhini; D007031:Hypothalamus / Q000502:physiology*; D008253:Macaca mulatta; D012527:Satiation / Q000502:physiology*; D012528:Satiety Response / Q000502:physiology*; D013649:Taste
D000661:Amphetamine