The regulation of food intake by selective stimulation of the type 3 melanocortin receptor (MC3R)

High levels of binding sites for melanocortin peptides exist within the arcuate nucleus, and a functional response to melanocortin peptides has been demonstrated in arcuate POMC neurons. Because the MC3R is thought to function as an inhibitory autoreceptor on POMC neurons, we reasoned that peripheral injections of MC3R-specific agonists would act within the arcuate nucleus to inhibit POMC neurons and thereby stimulate feeding. We demonstrate that the peptidergic MC3R agonist, d-Trp(8)-gamma-MSH, stimulates feeding via the MC3R when injected peripherally. These data provide the first evidence that feeding can be stimulated by peripheral injection of MC3R-specific agonists.