Modulation of brain reward circuitry by leptin

Leptin, a hormone secreted by fat cells, suppresses food intake and promote s weight Loss, To assess the action of this hormone on brain reward circuit ry, changes in the rewarding effect of Lateral hypothalamic stimulation wer e measured after leptin administration. At five stimulation sites near the fornix, the effectiveness of the rewarding electrical stimulation was enhan ced by chronic food restriction and attenuated by intracerebroventricular i nfusion of leptin. In contrast, the rewarding effect of stimulating neighbo ring sites was insensitive to chronic food restriction and was enhanced by leptin in three of four cases. These opposing effects of Leptin may mirror complementary changes in the rewarding effects of feeding and of competing behaviors.