Hypocretin (orexin) receptor 2, also known as OX2, is a human protein encoded by the HCRTR2 gene. Orexin A and orexin B are neuropeptides originally identified as endogenous ligands for OX2. Orexin neuropeptides are produced by a small group of neurons in the lateral hypothalamic and perifornical areas, a region that is classically implicated with the control of mammalian feeding behavior. Orexin neurons that project throughout the central nervous system to nuclei are known to be important in the control of feeding, sleep-wakefulness, neuroendocrine homeostasis, and autonomic regulation.