Opioid Receptors

Opioid receptors are currently classified into three groups, κ, δ and μ receptors. Subtypes within each group have been suggested including μ1, μ2, δ1, δ2, κ1, κ2, and κ3. An opioid-like receptor with a high degree of homology to μ, δ and κ-opioid receptors has been cloned and termed the orphan opioid receptor (NOP, ORL1). This receptor has a distinct pharmacological profile from the classical opioid receptors and an endogenous ligand, nociceptin (orphanin FQ) has been identified.

Opioid Receptor Target Files

Related Categories
Receptor Subtype μ (MOP, OP3) δ (DOP, OP1) κ (KOP, OP2) NOP (ORL1, OP4)
G protein Gi/o Gi/o Gi/o Gi/o
Transduction Mechanism Activation of inwardly rectifying K+ channels, inhibition of Ca2+ channels, inhibition of adenylyl cyclase
Localization Anterior cingulate cortex, neocortex, amygdala, hippocampus, ventral dentate gyrus, presubiculum, nucleus accumbens, caudate putamen, thalamus, habenula, interpeduncular nucleus, pars compacta of the substantia nigra, superior and inferior colliculi, raphe nuclei Medial habenula, hypothalamus, pons, medulla, dorsal root ganglion, caudate putamen, medial habenula, tegmentum, trigeminal nucleus Claustrum, endopiriform nucleus, caudate putamen, nucleus accumbens, midline nuclear group of the thalamus, superficial grey layer of the superior colliculus, central grey, caudate putamen, nucleus accumbens, amygdala, thalamus, interpeduncular nuclei Cortex, olfactory bulb, suprachiasmatic nucleus, amygdala, nucleus accumbens, thalamic nuclei, hypothalamus, hippocampus, septum, superior colliculus
Likely Physiological Roles Respiration, cardiovascular functions, feeding, learning and memory, intestinal transit, locomotor activity, thermoregulation, hormone secretion, immune functions Analgesia, motor integration, gastrointestinal motility, olfaction, respiration, cognitive function, mood driven behavior Regulation of nociception, diuresis, feeding, neuroendocrine secretions Motor and balance control, reinforcement and reward, nociception, the stress response, sexual behavior, aggression, autonomic control of physiological processes
Key Selective Agonists Endomorphin-1 (1055)
Endomorphin-2 (1056)
DAMGO (1171)
SNC 80 (0764)
SB 205607 (0921)
DPDPE (1431)
(±)-U-50488 (0495)
BRL 52537 (0699)
Dynorphin A (3195)
Nociceptin (0910)
MCOPPB (3763) SCH 221510 (3240)
Key Selective Antagonists β-Funaltrexamine (0926)
CTOP (1578)
Cyprodime (2601)
Naltrindole (0740)
Naltriben (0892)
BNTX maleate (0899)
nor-Binaltorphimine (0347)
DIPPA (0794)
GNTI (1282)
UFP-101 (1552)
(±)-J 113397 (2598)
JTC 801 (2481)

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