Mesencephalic lesions in female rats resulting in normophagia and reduced body weight.

The effects of bilateral mescencephalic lesions in the area of the ventral noradrenergic bundle (VNA) were studied in immature and mature female rats. The food intake consumption of the immature lesioned rats did not differ from sham operated controls whether fed a chow or high fat diet. However, after the surgery the body weights of the two groups began to diverge with the immature lesioned rats obtaining a significantly lower body weight. By the end of the study the immature lesioned rats were also significantly shorter than the controls. Both groups showed normal body composition throughout the measurement period. Upon refeeding after a one day fast the immature female rats defended their lower than normal pre-fast body weight. These data are in good agreement with our earlier findings using immature male rats. The mature lesioned animals also showed normal food consumption when fed a chow type diet. However the lesioned animals did show a brief hyperphagia when placed on a high fat diet. Unlike the immature lesioned rats the body weight of these lesioned animals did not differ from their sham operated controls. It is suggested that lesions in the area of the VNA may result in hyperphagia or, in no effects on food intake or body weight as reported by others or normophagia with reduced body weight. Exact lesion placement may be responsible for these divergent findings.