Arcuate neurons of overweight rats differ in their responses to amylin from controls.

Amylin and ghrelin are hormones produced, respectively, in pancreas and stomach. They have a central action on food intake and body weight. Possible changes in their effect on hypothalamic neuronal activity were investigated in overweight rats previously subjected to early postnatal overnutrition compared to controls. Single unit activity of brain slices was recorded in the medial arcuate that contains neuropeptide Y producing neurons. The orexigenic ghrelin activated neurons of both groups of rats. The anorexigenic amylin, however, significantly inhibited neurons of controls but not of overweight rats. The difference in the type of response to amylin shown by arcuate neurons of overweight rats can be regarded as expression of neonatally programmed neurochemical plasticity of the regulatory system of body weight.