Excessive weight gains in female rats with transections of the stria terminalis

Recent studies have demonstrated hyperphagia and excessive weight gains in female rats with small lesions in the most posterodorsal aspects of the medial amygdala. In the present study, similar results were observed in female rats with bilateral transections of the stria terminalis just as it exits the amygdala to begin its dorsal ascent (mean weight gain of 35.9 g/20 days compared to 0.1 g/20 days for operated control animals). Cellular damage caused by the retractable wire knife was limited to the caudal globus pallidus. The results of previous studies that failed to observe weight gains after stria terminalis transections were attributed to the use of male animals. The present results, along with the pattern of anterograde degeneration that is observed after obesity-inducing amygdaloid lesions, suggest a medial amygdala-stria terminalis-medial hypothalamic pathway in the regulation of food intake and body weight, but other possibilities are considered.