Role of the stria terminalis in food intake and body weight in rats

Abstract

Previous studies have shown that lesions of the posterodorsal amygdala result in hyperphagia and obesity in female rats. In the present study, lesions of the stria terminalis at its most dorsal point (before it separates into dorsal and ventral components) also resulted in hyperphagia and excessive weight gains in female rats compared to female rats with sham lesions, as did coronal knife cuts anterior to the ventromedial hypothalamus. Identical lesions and knife cuts did not elevate food intake or weight gains in male rats compared to male control animals. Examination of the anterograde degeneration with the amino-cupric-silver method in the brains of two female rats with hypothalamic knife cuts revealed degenerating terminals in the capsule of the ventromedial hypothalamus and in the premammillary nuclei, two classic indicators of damage to the dorsal component of the stria terminalis. No degenerating axon terminals were observed in the paraventricular nucleus. Differences from previous studies that used male rats were attributed to a sex difference for the effects of amygdaloid and ventromedial hypothalamic lesions. It is proposed that the posterodorsal amygdala, dorsal component of the stria terminalis, and ventromedial hypothalamus are part of an inhibitory pathway in the regulation of feeding behavior.