Neuropeptide

A class of peptides that act as signaling molecules in the nervous system. Neuropeptides are produced by neurons and released at synapses to modulate neural activity, pain perception, mood, appetite, and numerous other functions. Examples include endorphins, substance P, neuropeptide Y, and oxytocin. Research into neuropeptides has expanded understanding of pain pathways, reward systems, and neurodegenerative processes.