Orexin Receptor 1 (OX1R) (also known as hypocretin receptor 1) is one of two receptors that recognize the peptide neurotransmitters orexin A and orexin B. Orexin A and B are 33 and 28 amino acids in length, respectively, and are derived from a common precursor termed prepro-orexin.nOX1R binds orexin A with greater affinity than orexin B (a one order of magnitude difference), while OX2R binds both ligands with similar affinities.
