Amylin infusion into rat nucleus accumbens potently depresses motor activity and ingestive behavior

Amylin, a calcitonin gene-related peptide-like peptide coreleased with insu lin, exerts anorexic effects on central administration. Because previous st udies revealed dense amylin binding in the nucleus accumbens (Acb), we inve stigated the behavioral effects of amylin infusions (10, 30, and 100 ng/sid e) into Acb subregions. Intra-Acb shell amylin infusions decreased ambulati on, rearing, feeding, and drinking in either food-deprived rats or water-de prived rats; motor activity was affected more potently than ingestive behav ior. Moreover, intra-Acb shell amylin reduced motor activity in nondeprived rats tested in the absence of food or water, indicating that the expressio n of amylin's effects is independent of drive or proximal incentives. Intra -Acb core amylin infusions in water-deprived rats also decreased ambulation and water intake, although anterior Acb placements were associated with sm aller motor effects, regardless of Acb subregion. In contrast to amylin's e ffects, intra-Acb shell infusions of orexin-A (50, 100, and 500 ng/side) ha d no effects on motor activity, feeding, or drinking. Hence the Acb may be a target for behavioral regulation by satiety-related peptides like amylin.