Brain POMC Neurons: Comparative Aspects of Anatomy, Peptide Processing and Function

Neurons that produce proopiomelanocortin (POMC), and the biologically active peptides derived from POMC, play essential roles in feeding, body mass regulation and analgesia. Despite the documented importance of POMC peptides as neuromodulators there are only two populations of cells in the mammalian brain that synthesize this prohormone. POMC neurons in the arcuate nucleus of the hypothalamus have a well-documented role in the long-term control of food intake and body mass. Emerging work suggests an important role for the brainstem population of POMC neurons in the rapid control of food intake. There remain, however, many questions about the roles played by differentially processed forms of melanocortin and endorphin peptides. While we know with certainty that all gnathostomes have an infundibular POMC neuronal group, there are many unanswered questions about the evolution of these neurons and their role in long term energy storage and nutrient signaling. Almost nothing is known about brainstem POMC neurons in non-mammalian vertebrates or the anatomy of POMC neurons systems in agnathans. In this review I will summarize what we know about the location, post-translational processing, and function of POMC peptides in the vertebrate brain.