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Nociceptin receptor
Protein-coding gene in the species Homo sapiens / From Wikipedia, the free encyclopedia
The nociceptin opioid peptide receptor (NOP), also known as the nociceptin/orphanin FQ (N/OFQ) receptor or kappa-type 3 opioid receptor, is a protein that in humans is encoded by the OPRL1 (opioid receptor-like 1) gene.[5] The nociceptin receptor is a member of the opioid subfamily of G protein-coupled receptors whose natural ligand is the 17 amino acid neuropeptide known as nociceptin (N/OFQ).[6] This receptor is involved in the regulation of numerous brain activities, particularly instinctive and emotional behaviors.[7] Antagonists targeting NOP are under investigation for their role as treatments for depression and Parkinson's disease, whereas NOP agonists have been shown to act as powerful, non-addictive painkillers in non-human primates.
Although NOP shares high sequence identity (~60%) with the ‘classical’ opioid receptors μ-OP (MOP), κ-OP (KOP), and δ-OP (DOP), it possesses little or no affinity for opioid peptides or morphine-like compounds.[8] Likewise, classical opioid receptors possess little affinity towards NOP's endogenous ligand nociceptin, which is structurally related to dynorphin A.[8]