CARTPT and Cachexia: In contrast, proopiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART) neurons exert opposite effects.61 POMC and AgRP neurons residing in the hypothalamic arcuate nucleus serve as critical regulators of melanocortin signaling in the CNS, which is associated with cachexia-related appetite dysfunction through POMC activation and AgRP suppression.62,63 There are five melanocortin receptors (MCRs) known to exist.