A re-examination of septal lesion-induced weight gain in female rats.

Previous studies that examined the effects of knife cuts ventral to the septal area, or the pattern of anterograde degeneration after other obesity-inducing lesions or cuts, have implicated the septal area in feeding behavior. However, lesion studies have been inconsistent. In the present study, large electrolytic lesions that destroyed all or nearly all of the septal area resulted in excessive weight gain in female rats (25 g/20 days compared to 1 g/20 days for controls). Lesions confined to the ventral septum produced equal weight gains, but rats with lesions confined to the dorsal septum did not differ from controls. The excessive weight gains were accompanied by modest hyperphagia. The weight gains were not the result of incidental damage to adjacent structures such as the stria terminalis or the shell of the nucleus accumbens. It is concluded that the ventral portion of the septum is part of a limbic-hypothalamic circuitry regulating food intake in female rats.