alpha-Melanocyte stimulating hormone (alpha-MSH) and other melanocortin peptides are potent anti-inflammatory agents that exhibit efficacy in many animal models of acute and chronic inflammation. These peptides are produced both centrally and peripherally, and exert their biological actions via activation of membrane-bound receptors. To exploit the therapeutic potential of such anti-inflammatory peptides, it is essential that the receptor subtype mediating these effects is identified with certainty.