Nociceptin receptor

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

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

Ligands
Several commonly used opioid drugs including is_associated_with::etorphine and is_associated_with::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.

Agonists

 * is_associated_with::Buprenorphine (partial agonist, not selective for NOP, also partial agonist of µ-opioid and δ-opioid receptors, and competitive antagonist of κ-opioid receptors)
 * is_associated_with::Cebranopadol (full agonist at NOP, μ-opioid and δ-opioid receptors, partial agonist at κ-opioid receptor)
 * is_associated_with::Etorphine
 * is_associated_with::MCOPPB (full agonist, CAS# 1028969-49-4)
 * is_associated_with::MT-7716
 * is_associated_with::Nociceptin
 * is_associated_with::Norbuprenorphine (full agonist; non-selective (also full agonist at the MOR and DOR and partial agonist at the KOR); peripherally-selective)
 * is_associated_with::NNC 63-0532
 * is_associated_with::Ro64-6198
 * is_associated_with::Ro65-6570
 * is_associated_with::SCH-221,510
 * is_associated_with::SR-8993
 * is_associated_with::SR-16435 (mixed MOR / NOP partial agonist)
 * is_associated_with::TH-030418

Antagonists

 * is_associated_with::AT-076 (non-selective)
 * is_associated_with::JTC-801
 * is_associated_with::J-113,397
 * is_associated_with::LY-2940094
 * is_associated_with::SB-612,111
 * is_associated_with::SR-16430
 * is_associated_with::Thienorphine

Applications
NOP is_associated_with::agonists are being studied as treatments for is_associated_with::heart failure and is_associated_with::migraine while nociceptin antagonists such as is_associated_with::JTC-801 may have is_associated_with::analgesic and is_associated_with::antidepressant qualities.