Nociceptin receptor

Nociceptin receptor

Opiate receptor-like 1
Available structures
PDB Ortholog search: PDBe, RCSB
Symbols  ; KOR-3; NOCIR; OOR; ORL1
External IDs IUPHAR: ChEMBL: GeneCards:
Species Human Mouse
RefSeq (mRNA)
RefSeq (protein)
Location (UCSC)
PubMed search

The nociceptin receptor or NOP also known as the orphanin FQ receptor or kappa-type 3 opioid receptor is a protein that in humans is encoded by the OPRL1 (opioid receptor-like 1) gene.[1] The nociceptin receptor is a G protein-coupled receptor whose natural ligand is known as nociceptin or orphanin FQ, a 17 amino acid neuropeptide.[2] This receptor is involved in the regulation of numerous brain activities, particularly instinctive and emotional behaviors.[3]


Nociceptin is thought to be an endogenous antagonist of dopamine transport that may act either directly on dopamine or by inhibiting GABA to affect dopamine levels.[4] Within the central nervous system its action can be either similar or opposite to those of opioids depending on their location.[5] It controls a wide range of biological functions ranging from nociception to food intake, from memory processes to cardiovascular and renal functions, from spontaneous locomotor activity to gastrointestinal motility, from anxiety to the control of neurotransmitter release at peripheral and central sites.[5]

Selective ligands

Several commonly used opioid drugs including etorphine and buprenorphine have been demonstrated to bind to nociceptin receptors, but this binding is relatively insignificant compared to their activity at other opioid receptors. More recently a range of selective ligands for NOP have been developed, which show little or no affinity to other opioid receptors and so allow NOP-mediated responses to be studied in isolation.


  • Buprenorphine (partial agonist, not selective for NOP, also partial agonist of µ-opioid and δ-opioid receptors, and competitive antagonist of κ-opioid receptors)
  • Cebranopadol (full agonist at NOP, μ-opioid and δ-opioid receptors, partial agonist at κ-opioid receptor)
  • Etorphine
  • MT-7716
  • Nociceptin
  • Norbuprenorphine (full agonist; non-selective (also full agonist at the MOR and DOR and partial agonist at the KOR; peripherally-selective)
  • NNC 63-0532
  • Ro64-6198
  • Ro65-6570
  • SCH-221,510
  • SR-8993
  • SR-16435 (mixed MOR / NOP partial agonist)
  • MCOPPB[6] (full agonist, CAS# 1028969-49-4)



NOP agonists are being studied as treatments for heart failure and migraine[7] while nociceptin antagonists such as JTC-801 may have analgesic[8] and antidepressant qualities.[9]


  1. ^ Mollereau C, Parmentier M, Mailleux P, Butour JL, Moisand C, Chalon P, Caput D, Vassart G, Meunier JC (March 1994). "ORL1, a novel member of the opioid receptor family. Cloning, functional expression and localization". FEBS Lett. 341 (1): 33–8.  
  2. ^ Henderson G, McKnight AT (August 1997). "The orphan opioid receptor and its endogenous ligand--nociceptin/orphanin FQ". Trends Pharmacol. Sci. 18 (8): 293–300.  
  3. ^ "Entrez Gene: OPRL1 opiate receptor-like 1". 
  4. ^ Liu Z, Wang Y, Zhang J, Ding J, Guo L, Cui D, Fei J (March 2001). "Orphanin FQ: an endogenous antagonist of rat brain dopamine transporter". NeuroReport 12 (4): 699–702.  
  5. ^ a b Calo' G, Guerrini R, Rizzi A, Salvadori S, Regoli D (April 2000). "Pharmacology of nociceptin and its receptor: a novel therapeutic target". Br. J. Pharmacol. 129 (7): 1261–83.  
  6. ^ Hirao A, Imai A, Sugie Y, Yamada Y, Hayashi S, Toide K. Pharmacological characterization of the newly synthesized nociceptin/orphanin FQ-receptor agonist 1-[1-(1-methylcyclooctyl)-4-piperidinyl]-2-[(3R)-3-piperidinyl]-1H-benzimidazole as an anxiolytic agent. Journal of Pharmacological Sciences. 2008 Mar;106(3):361-8. PMID 18319566
  7. ^ Mørk H, Hommel K, Uddman R, Edvinsson L, Jensen R (September 2002). "Does nociceptin play a role in pain disorders in man?". Peptides 23 (9): 1581–7.  
  8. ^ Scoto GM, Aricò G, Ronsisvalle S, Parenti C (July 2007). "Blockade of the nociceptin/orphanin FQ/NOP receptor system in the rat ventrolateral periaqueductal gray potentiates DAMGO analgesia". Peptides 28 (7): 1441–6.  
  9. ^ Redrobe JP, Calo' G, Regoli D, Quirion R (February 2002). "Nociceptin receptor antagonists display antidepressant-like properties in the mouse forced swimming test". Naunyn Schmiedebergs Arch. Pharmacol. 365 (2): 164–7.  

Further reading

External links

This article incorporates text from the United States National Library of Medicine, which is in the public domain.