EFFECTS OF LESIONS OF NUCLEUS ACCUMBENS ON FOOD-INTAKE AND BODY-WEIGHT

Food and water intake and body weight of rats with lesions in the nucleus accumbens (NA) were monitored for several months, extending from a 4 wk period prior to the lesion, through a 4 wk postoperative period, gestation, parturition, to the end of a 3 wk postpartum period. The most pronounced lesion-precipitated change related to energy balance was elevated consumption of food, relative to the experimental rats'' own prelesion intake and to that of a sham control group. The apparent hyperphagia was not accompanied by increases in body weight. Except for prelesion weights, weights of rats with 50% or greater bilateral destruction of the NA or damage to at least 75% of the NA of 1 hemisphere lagged consistently, although not significantly (except during the postpartum period), behind those of animals with less extensive lesions and sham controls. Observations made during gestation and the postpartum period clearly indicated that lesions did not affect ability to respond to changes in the animal''s physiology with appropriate adjustment of food intake. Enhanced ingestion of food during the postlesion period was a secondary outcome of the increased demands imposed upon energy reserves by the hyperactivity and emotionality induced by the lesion.