Orexin A (human, rat, mouse) (Hypocretin-1 (human, rat, mouse)), a 33 amino acid excitatory neuropeptide, orchestrates diverse central and peripheral processes. Orexin A (human, rat, mouse) binds and activates two types of G protein-coupled receptors, the orexin-1 receptor (OX1R) and the orexin-2 receptor (OX2R). Orexin A (human, rat, mouse) has a role in the regulation of feeding behavior. Orexin A (human, rat, mouse) is an effective anti-nociceptive and anti-hyperalgesic agent in mice and rats.