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μ receptor

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Target id: 319

Nomenclature: μ receptor

Family: Opioid receptors

Gene and Protein Information Click here for help
class A G protein-coupled receptor
Species TM AA Chromosomal Location Gene Symbol Gene Name Reference
Human 7 400 6q25.2 OPRM1 opioid receptor mu 1 170
Mouse 7 398 10 1.85 cM Oprm1 opioid receptor, mu 1 107
Rat 7 398 1q11 Oprm1 opioid receptor, mu 1 25,45,152,169,180
Previous and Unofficial Names Click here for help
Mu receptor | MOP | OP3 | MOPr | opioid receptor, mu 1 | opioid receptor
Database Links Click here for help
Specialist databases
GPCRDB oprm_human (Hs), oprm_mouse (Mm), oprm_rat (Rn)
Other databases
Alphafold
ChEMBL Target
DrugBank Target
Ensembl Gene
Entrez Gene
Human Protein Atlas
KEGG Gene
OMIM
Pharos
RefSeq Nucleotide
RefSeq Protein
SynPHARM
UniProtKB
Wikipedia
Selected 3D Structures Click here for help
Image of receptor 3D structure from RCSB PDB
Description:  Crystal structure of the mu-opioid receptor bound to a morphinan antagonist
PDB Id:  4DKL
Ligand:  β-FNA
Resolution:  2.8Å
Species:  Mouse
References:  95
Image of receptor 3D structure from RCSB PDB
Description:  Structure of the μ-opioid receptor–Gi protein complex
PDB Id:  6DDF
Ligand:  DAMGO
Resolution:  3.5Å
Species:  Mouse
References:  79
Natural/Endogenous Ligands Click here for help
dynorphin A-(1-13) {Sp: Human, Mouse, Rat}
dynorphin A {Sp: Human, Mouse, Rat}
dynorphin A-(1-8) {Sp: Human, Mouse, Rat}
dynorphin B {Sp: Human, Mouse, Rat}
endomorphin-1 {Sp: Human}
endomorphin-2 {Sp: Human}
β-endorphin {Sp: Human} , β-endorphin {Sp: Mouse} , β-endorphin {Sp: Rat}
[Leu]enkephalin {Sp: Human, Mouse, Rat}
[Met]enkephalin {Sp: Human, Mouse, Rat}
Comments: β-Endorphin is the highest potency endogenous ligand
Potential endogenous agonists
endomorphin-1, endomorphin-2
Principal endogenous agonists (Human)
β-endorphin (POMC, P01189), [Met]enkephalin (PENK, P01210), [Leu]enkephalin (PENK, P01210)

Download all structure-activity data for this target as a CSV file go icon to follow link

Agonists
Key to terms and symbols View all chemical structures Click column headers to sort
Ligand Sp. Action Value Parameter Reference
[3H]DAMGO Peptide Ligand is labelled Ligand is radioactive Rn Full agonist 9.2 pKd 134
pKd 9.2 (Kd 5.7x10-10 M) [134]
carfentanil Small molecule or natural product Click here for species-specific activity table Cp Agonist 10.6 pKi 33
pKi 10.6 (Ki 2.4x10-11 M) [33]
Description: Binding affinity in guinea pig whole brain- displacement of [3H]DAGO binding.
(-)-cyclazocine Small molecule or natural product Click here for species-specific activity table Hs Partial agonist 10.0 pKi 156
pKi 10.0 [156]
butorphanol Small molecule or natural product Approved drug Primary target of this compound Click here for species-specific activity table Hs Partial agonist 9.9 pKi 47
pKi 9.9 (Ki 1.2x10-10 M) [47]
Description: Displacement of [3H]DAMGO from human μ opioid receptor expressed in CHO cells.
sufentanil Small molecule or natural product Approved drug Primary target of this compound Hs Full agonist 9.9 pKi 165
pKi 9.9 (Ki 1.38x10-10 M) [165]
etonitazene Small molecule or natural product Click here for species-specific activity table Hs Full agonist 9.7 pKi 156
pKi 9.7 [156]
hydromorphone Small molecule or natural product Approved drug Primary target of this compound Click here for species-specific activity table Hs Agonist 9.6 pKi 171
pKi 9.6 (Ki 2.8x10-10 M) [171]
ethylketocyclazocine Small molecule or natural product Click here for species-specific activity table Hs Full agonist 9.5 pKi 156
pKi 9.5 [156]
etorphine Small molecule or natural product Click here for species-specific activity table Hs Full agonist 9.5 pKi 156
pKi 9.5 [156]
fentanyl Small molecule or natural product Approved drug Ligand has a PDB structure Rn Full agonist 9.4 pKi 134
pKi 9.4 [134]
DAMGO Peptide Click here for species-specific activity table Hs Full agonist 9.3 pKi 58,156
pKi 9.3 [58,156]
loperamide Small molecule or natural product Approved drug Primary target of this compound Hs Agonist 9.3 pKi 26
pKi 9.3 (Ki 5.3x10-10 M) [26]
(-)-methadone Small molecule or natural product Click here for species-specific activity table Hs Full agonist 9.2 pKi 156
pKi 9.2 [156]
[Met]enkephalin {Sp: Human, Mouse, Rat} Peptide Click here for species-specific activity table Ligand is endogenous in the given species Immunopharmacology Ligand Rn Full agonist 9.2 pKi 134
pKi 9.2 [134]
fentanyl Small molecule or natural product Approved drug Primary target of this compound Click here for species-specific activity table Ligand has a PDB structure Hs Full agonist 9.2 pKi 156
pKi 9.2 [156]
cebranopadol Small molecule or natural product Click here for species-specific activity table Hs Agonist 9.1 pKi 90
pKi 9.1 (Ki 7x10-10 M) [90]
Description: Radioligand binding assay
sufentanil Small molecule or natural product Approved drug Rn Full agonist 9.1 pKi 174
pKi 9.1 (Ki 7.7x10-10 M) [174]
eluxadoline Small molecule or natural product Approved drug Click here for species-specific activity table Rn Agonist 9.1 pKi 18
pKi 9.1 (Ki 9x10-10 M) [18]
morphine Small molecule or natural product Approved drug Primary target of this compound Click here for species-specific activity table Ligand has a PDB structure Hs Full agonist 9.0 pKi 52,156
pKi 9.0 [52,156]
β-endorphin {Sp: Human} Peptide Click here for species-specific activity table Rn Full agonist 9.0 pKi 134
pKi 9.0 [134]
PZM21 Small molecule or natural product Primary target of this compound Hs Biased agonist 9.0 pKi 96
pKi 9.0 (Ki 1.1x10-9 M) [96]
bilorphin Small molecule or natural product Primary target of this compound Click here for species-specific activity table Hs Agonist 9.0 pKi 36
pKi 9.0 (Ki 1.1x10-9 M) [36]
dihydromorphine Small molecule or natural product Click here for species-specific activity table Hs Full agonist 8.8 pKi 156
pKi 8.8 [156]
dynorphin-(1-11) Peptide Click here for species-specific activity table Hs Full agonist 8.8 pKi 156
pKi 8.8 [156]
normorphine Small molecule or natural product Click here for species-specific activity table Hs Full agonist 8.8 pKi 156
pKi 8.8 [156]
nalbuphine Small molecule or natural product Approved drug Primary target of this compound Click here for species-specific activity table Hs Agonist 8.8 pKi 171
pKi 8.8 (Ki 1.6x10-9 M) [171]
buprenorphine Small molecule or natural product Approved drug Primary target of this compound Click here for species-specific activity table Hs Partial agonist 8.8 pKi 156
pKi 8.8 [156]
eluxadoline Small molecule or natural product Approved drug Hs Agonist 8.8 pKi 18
pKi 8.8 (Ki 1.7x10-9 M) [18]
DADLE Peptide Click here for species-specific activity table Hs Full agonist 8.7 pKi 156
pKi 8.7 [156]
DAMGO Peptide Click here for species-specific activity table Rn Full agonist 8.7 pKi 134
pKi 8.7 [134]
hydrocodone Small molecule or natural product Approved drug Primary target of this compound Click here for species-specific activity table Hs Agonist 8.7 pKi 121
pKi 8.7 (Ki 2x10-9 M) [121]
BU08028 Small molecule or natural product Click here for species-specific activity table Hs Partial agonist 8.7 pKi 74
pKi 8.7 (Ki 2.14x10-9 M) [74]
cebranopadol Small molecule or natural product Click here for species-specific activity table Rn Agonist 8.6 pKi 90
pKi 8.6 (Ki 2.4x10-9 M) [90]
Description: Radioligand binding assay
dynorphin B {Sp: Human, Mouse, Rat} Peptide Click here for species-specific activity table Ligand is endogenous in the given species Hs Full agonist 8.5 pKi 156
pKi 8.5 [156]
endomorphin-2 {Sp: Human} Peptide Ligand is endogenous in the given species Rn Full agonist 8.5 pKi 179
pKi 8.5 (Ki 3.24x10-9 M) [179]
(-)-pentazocine Small molecule or natural product Approved drug Click here for species-specific activity table Hs Partial agonist 8.4 pKi 156
pKi 8.4 [156]
dynorphin A-(1-8) {Sp: Human, Mouse, Rat} Peptide Click here for species-specific activity table Ligand is endogenous in the given species Hs Full agonist 8.4 pKi 156
pKi 8.4 [156]
dynorphin A-(1-13) {Sp: Human, Mouse, Rat} Peptide Click here for species-specific activity table Ligand is endogenous in the given species Hs Full agonist 8.3 pKi 156
pKi 8.3 [156]
endomorphin-1 {Sp: Human} Peptide Click here for species-specific activity table Ligand is endogenous in the given species Hs Full agonist 8.3 pKi 54,179
pKi 8.3 (Ki 5.01x10-9 M) [54,179]
DSLET Peptide Click here for species-specific activity table Hs Full agonist 8.2 pKi 156
pKi 8.2 [156]
PL017 Peptide Hs Full agonist 8.2 pKi 23,156
pKi 8.2 [23,156]
[Leu]enkephalin {Sp: Human, Mouse, Rat} Peptide Click here for species-specific activity table Ligand is endogenous in the given species Hs Partial agonist 8.1 pKi 156
pKi 8.1 [156]
dynorphin A {Sp: Human, Mouse, Rat} Peptide Click here for species-specific activity table Ligand is endogenous in the given species Hs Full agonist 8.1 pKi 156
pKi 8.1 [156]
UFP-512 Small molecule or natural product Click here for species-specific activity table Hs Agonist 8.0 pKi 164
pKi 8.0 [164]
Description: Measuring displacement of [3H]-diprenorphine in vitro
morphine Small molecule or natural product Approved drug Click here for species-specific activity table Ligand has a PDB structure Rn Partial agonist 7.9 pKi 134
pKi 7.9 [134]
BW373U86 Small molecule or natural product Click here for species-specific activity table Rn Agonist 7.8 pKi 22
pKi 7.8 (Ki 1.5x10-8 M) [22]
UFP-505 Small molecule or natural product Click here for species-specific activity table Hs Agonist 7.8 pKi 38-39
pKi 7.8 [38-39]
ADL5747 Small molecule or natural product Click here for species-specific activity table Hs Agonist 7.7 pKi 85
pKi 7.7 (Ki 1.8x10-8 M) [85]
SRI22141 Small molecule or natural product Click here for species-specific activity table Hs Agonist 7.7 pKi 87
pKi 7.7 (Ki 1.97x10-8 M) [87]
Description: Binding affinity
ADL5859 Small molecule or natural product Click here for species-specific activity table Hs Agonist 7.5 pKi 84
pKi 7.5 (Ki 3.2x10-8 M) [84]
ICI-199441 Small molecule or natural product Click here for species-specific activity table Hs Agonist 7.3 pKi 81
pKi 7.3 (Ki 5.3x10-8 M) [81]
Description: Displacement of [3H]diprenorphine from human μ opioid receptor expressed in CHO-K1 cells
SCH221510 Small molecule or natural product Click here for species-specific activity table Hs Agonist 7.2 pKi 163
pKi 7.2 (Ki 6.5x10-8 M) [163]
Description: Radioligand binding assay
SR16835 Small molecule or natural product Click here for species-specific activity table Hs Agonist 7.1 pKi 157
pKi 7.1 (Ki 7.99x10-8 M) [157]
Description: Radioligand binding assay
codeine Small molecule or natural product Approved drug Primary target of this compound Hs Full agonist 6.9 pKi 156
pKi 6.9 [156]
tapentadol Small molecule or natural product Approved drug Primary target of this compound Click here for species-specific activity table Hs Agonist 6.8 pKi 159
pKi 6.8 (Ki 1.6x10-7 M) [159]
oxycodegol Small molecule or natural product Click here for species-specific activity table Hs Agonist 6.6 pKi 110
pKi 6.6 (Ki 2.37x10-7 M) [110]
Description: Competitive membrane binding assay measuring displacement [3H]naloxone from human μ receptors expressed by CHO cells.
BW373U86 Small molecule or natural product Click here for species-specific activity table Hs Agonist 6.6 pKi 84
pKi 6.6 (Ki 2.6x10-7 M) [84]
HS665 Small molecule or natural product Click here for species-specific activity table Hs Agonist 6.3 pKi 147
pKi 6.3 (Ki 5.42x10-7 M) [147]
compound 3 [PMID: 23134120] Small molecule or natural product Click here for species-specific activity table Hs Agonist 6.1 pKi 147
pKi 6.1 (Ki 8.26x10-7 M) [147]
tramadol Small molecule or natural product Approved drug Click here for species-specific activity table Hs Agonist 5.8 pKi 171
pKi 5.8 (Ki 1.6x10-6 M) [171]
Description: Displacement of the mu aginist peptide DAMGO from the mu receptor expressed in CHO cells.
SRI22141 Small molecule or natural product Click here for species-specific activity table Hs Agonist 9.7 pEC50 87
pEC50 9.7 (EC50 2x10-10 M) [87]
Description: Potency in a 35S-GTPγS assay
PZM21 Small molecule or natural product Primary target of this compound Hs Biased agonist 8.3 pEC50 96
pEC50 8.3 (EC50 4.6x10-9 M) [96]
Description: In a Gi/o activation assay.
4F-MT-45 Small molecule or natural product Hs Agonist 6.8 pEC50 8
pEC50 6.8 (EC50 1.7x10-7 M) [8]
Description: β-arrestin2 recruitment assay
2F-MT-45 Small molecule or natural product Hs Agonist 6.7 pEC50 8
pEC50 6.7 (EC50 2x10-7 M) [8]
Description: β-arrestin2 recruitment assay
3F-MT-45 Small molecule or natural product Hs Agonist 6.2 pEC50 8
pEC50 6.2 (EC50 6.1x10-7 M) [8]
Description: β-arrestin2 recruitment assay
MT-45 Small molecule or natural product Hs Agonist 4.6 pEC50 8
pEC50 4.6 (EC50 2.3x10-5 M) [8]
Description: β-arrestin2 recruitment assay
levorphanol Small molecule or natural product Approved drug Primary target of this compound Click here for species-specific activity table Hs Agonist 9.9 pIC50 60
pIC50 9.9 (IC50 1.3x10-10 M) [60]
BU72 Small molecule or natural product Ligand has a PDB structure Cp Agonist 9.8 pIC50 65
pIC50 9.8 (IC50 1.5x10-10 M) [65]
Description: Measuring displacement of [3H]DAMGO from brain membranes isolated from Hartley guinea pigs.
methadone Small molecule or natural product Approved drug Primary target of this compound Hs Agonist 8.4 pIC50 132
pIC50 8.4 (IC50 4.1x10-9 M) [132]
Description: Binding affinity against μ-opioid receptor (human) using [3H]DAMGO radioligand.
pethidine Small molecule or natural product Approved drug Primary target of this compound Click here for species-specific activity table Hs Agonist 6.5 pIC50 132
pIC50 6.5 (IC50 3.15x10-7 M) [132]
AR-M1000390 Small molecule or natural product Click here for species-specific activity table Hs Agonist 5.4 pIC50 4
pIC50 5.4 (IC50 3.8x10-6 M) [4]
[3H]PL017 Peptide Ligand is labelled Ligand is radioactive Rn Agonist - - 61
[61]
U-47700 Small molecule or natural product Rn Agonist - - 27
[27]
View species-specific agonist tables
Agonist Comments
Discrimination of full or partial agonism is very dependent on the level of receptor expression and on the assay used to monitor agonist effects. Many agents may behave as full agonists or potent partial agonists in cell lines expressing cloned receptors in high concentration, but in other environments they may show only weak agonist activity. The identification of agonist activity in the table is largely based on the ability to stimulate GTPγ35S binding in cell lines expressing cloned human μ receptors. Agents giving 85% or greater stimulation than that given by DAMGO have been characterized as Full Agonists [156].

It is still unclear whether endomorphins are endogenous. Morphine occurs endogenously [131].

We have tagged the μ receptor as the primary drug target for hydrocodone based on this drug having the highest affinity at this receptor compared to the κ and δ receptors [121]. Similarly, we have tagged the μ receptor as the primary target of hydromorphone [171].

Methadone is selective for the μ receptor: comparable IC50s at the κ and δ receptors are 512 and 1090nM respectively [132].

[11C]carfentanil (PubChem CID 449698) binds the human μ receptor with a Ki of 0.07 nM, in a [3H]DAMGO displacement assay [62].
Antagonists
Key to terms and symbols View all chemical structures Click column headers to sort
Ligand Sp. Action Value Parameter Reference
[3H]diprenorphine Small molecule or natural product Ligand is labelled Ligand is radioactive Mm Antagonist 10.1 pKd 134
pKd 10.1 (Kd 7.94x10-11 M) [134]
[3H]naloxone Small molecule or natural product Ligand is labelled Ligand is radioactive Rn Antagonist 8.6 – 9.0 pKd 123
pKd 8.6 – 9.0 (Kd 2.8x10-9 – 1x10-9 M) [123]
Description: CHO and BHK cell lines stably expressing the rat μ receptor
naloxonazine Small molecule or natural product Mm Antagonist 10.3 pKi 134
pKi 10.3 [134]
samidorphan Small molecule or natural product Approved drug Click here for species-specific activity table Hs Antagonist 10.3 pKi 172
pKi 10.3 (Ki 5.2x10-11 M) [172]
diprenorphine Small molecule or natural product Mm Antagonist 10.1 pKi 134
pKi 10.1 [134]
quadazocine Small molecule or natural product Click here for species-specific activity table Hs Antagonist 10.0 pKi 156
pKi 10.0 [156]
(-)-bremazocine Small molecule or natural product Click here for species-specific activity table Hs Antagonist 9.7 pKi 156
pKi 9.7 [156]
CTOP Peptide Hs Antagonist 9.7 pKi 134
pKi 9.7 [134]
nalmefene Small molecule or natural product Approved drug Primary target of this compound Click here for species-specific activity table Hs Antagonist 9.5 pKi 156
pKi 9.5 [156]
β-FNA Small molecule or natural product Click here for species-specific activity table Hs Antagonist 9.5 pKi 156
pKi 9.5 [156]
β-FNA Small molecule or natural product Mm Antagonist 9.5 pKi 134
pKi 9.5 [134]
NFP Small molecule or natural product Click here for species-specific activity table Hs Antagonist 9.4 pKi 182
pKi 9.4 (Ki 3.6x10-10 M) [182]
Description: In a competitive radioligand membrane binding assay measuring displacement of [3H]naloxone by NFP from μ receptor expressed in CHO cells.
naltrexone Small molecule or natural product Approved drug Primary target of this compound Click here for species-specific activity table Hs Antagonist 9.1 – 9.7 pKi 73,156
pKi 9.1 – 9.7 (Ki 7.1x10-10 – 1.99x10-10 M) [73,156]
GSK1521498 Small molecule or natural product Primary target of this compound Hs Antagonist 9.4 pKi 73
pKi 9.4 (Ki 4.17x10-10 M) [73]
alvimopan Small molecule or natural product Approved drug Primary target of this compound Click here for species-specific activity table Hs Antagonist 9.3 pKi 83
pKi 9.3 (Ki 4.7x10-10 M) [83]
diprenorphine Small molecule or natural product Click here for species-specific activity table Hs Antagonist 9.1 pKi 156
pKi 9.1 [156]
levallorphan Small molecule or natural product Approved drug Primary target of this compound Hs Antagonist 8.8 – 9.3 pKi 94
pKi 8.8 – 9.3 (Ki 1.69x10-9 – 4.8x10-10 M) [94]
Description: Competition binding assay- the calculated Ki varies depending on the radioligand used.
naloxone Small molecule or natural product Approved drug Click here for species-specific activity table Mm Antagonist 9.0 pKi 134
pKi 9.0 [134]
naldemedine Small molecule or natural product Approved drug Primary target of this compound Click here for species-specific activity table Hs Antagonist 8.9 pKi 67
pKi 8.9 (Ki 1.13x10-9 M) [67]
nalorphine Small molecule or natural product Approved drug Primary target of this compound Click here for species-specific activity table Hs Antagonist 8.9 pKi 156
pKi 8.9 [156]
naloxone Small molecule or natural product Approved drug Click here for species-specific activity table Hs Antagonist 8.9 pKi 156
pKi 8.9 [156]
BNTX Small molecule or natural product Click here for species-specific activity table Hs Antagonist 8.8 pKi 156
pKi 8.8 [156]
AT-076 Small molecule or natural product Click here for species-specific activity table Hs Antagonist 8.8 pKi 156,181
pKi 8.8 (Ki 1.67x10-9 M) [156,181]
Description: Radioligand binding assay
methylnaltrexone Small molecule or natural product Approved drug Primary target of this compound Click here for species-specific activity table Hs Antagonist 8.7 pKi 171
pKi 8.7 (Ki 2x10-9 M) [171]
Description: Displacement of [3H]DAMGO from human μ opioid receptors expressed in CHO cells
CTAP Peptide Click here for species-specific activity table Hs Antagonist 8.6 pKi 23,156
pKi 8.6 [23,156]
naloxone benzoylhydrazone Small molecule or natural product Click here for species-specific activity table Hs Antagonist 8.2 – 8.7 pKi 156
pKi 8.7 [156]
pKi 8.2 [156]
naltrindole Small molecule or natural product Click here for species-specific activity table Ligand has a PDB structure Hs Antagonist 8.2 pKi 156
pKi 8.2 [156]
naltriben Small molecule or natural product Click here for species-specific activity table Hs Antagonist 7.9 pKi 156
pKi 7.9 [156]
nor-binaltorphimine Small molecule or natural product Click here for species-specific activity table Hs Antagonist 7.7 pKi 156
pKi 7.7 [156]
LY2456302 Small molecule or natural product Click here for species-specific activity table Hs Antagonist 7.6 pKi 136
pKi 7.6 (Ki 2.4x10-8 M) [136]
zyklophin Peptide Click here for species-specific activity table Hs Antagonist 5.2 pKi 125
pKi 5.2 (Ki 5.88x10-6 M) [125]
BTRX-335140 Small molecule or natural product Click here for species-specific activity table Hs Antagonist 7.0 pIC50 55
pIC50 7.0 (IC50 1.1x10-7 M) [55]
View species-specific antagonist tables
Antagonist Comments
β-FNA is an electrophilic affinity label. The pKi reflects both the reversible and irreversible binding components.
CTOP is a good somatostatin receptor (sst receptor) agonist in addition to having antagonist activity at μ opioid receptors; it should never be used in studies of μ receptor function in situations where sst receptors may be involved. CTAP does not activate sst receptors [31].

The μ receptor is tagged as the primary target for the drug levallorphan, since the drug is mainly used for its antagonistic actions as an antidote to opioid overdose. Note that this drug also acts as a partial agonist at the κ receptor.
Allosteric Modulators
Key to terms and symbols View all chemical structures Click column headers to sort
Ligand Sp. Action Value Parameter Reference
BMS-986123 Small molecule or natural product Hs Neutral 6.0 pKB 19
pKB 6.0 (KB 1x10-6 M) [19]
BMS-986121 Small molecule or natural product Hs Positive 5.7 pKB 19
pKB 5.7 (KB 2x10-6 M) [19]
BMS-986124 Small molecule or natural product Hs Neutral 5.7 pKB 19
pKB 5.7 (KB 2x10-6 M) [19]
BMS-986122 Small molecule or natural product Hs Positive 5.3 pKB 19
pKB 5.3 (KB 5x10-6 M) [19]
BMS-986187 Small molecule or natural product Rn Positive 7.2 pKi 91
pKi 7.2 (Ki 6.3x10-8 M) In the presence of 10 μM BMS-986187, the affinity of the μ-OR agonist DAMGO was enhanced 11-fold from 724 nM to 63 nM. [91]
BMS-986121 Small molecule or natural product Hs Positive 6.0 pEC50 19
pEC50 6.0 (EC50 1x10-6 M) [19]
BMS-986122 Small molecule or natural product Hs Positive 5.5 pEC50 19
pEC50 5.5 (EC50 3x10-6 M) [19]
View species-specific allosteric modulator tables
Allosteric Modulator Comments
BMS-986123 and BMS-986124 are Silent Allosteric Modulators (SAMs). These compounds neither potentiate nor inhibit the actions of an orthosteric agonist, however they block the actions of the Positive Allosteric Modulators (PAMs).
A number of proteins such as G protein-coupled receptor kinases, β-arrestins and G proteins clearly regulate μ opioid receptor affinities and function. In addition sodium and guanyl nucleotides can modify the functional μ receptor complex and G protein interaction. Also, μ receptors are reported to form heterodimers with other receptors of the OP family or with non-opioid G protein-coupled receptors. Heterodimerisation may alter μ receptor function and/or trafficking [49,53,126].
Other Binding Ligands
Key to terms and symbols Click column headers to sort
Ligand Sp. Action Value Parameter Reference
compound 16 [PMID: 31498617] Small molecule or natural product Click here for species-specific activity table Hs Binding 5.4 pKi 133
pKi 5.4 (Ki 3.73x10-6 M) [133]
Description: Receptor binding in a radioligand displacement assay using [3H]DAMGO as tracer.
Immuno Process Associations
Immuno Process:  Cytokine production & signalling
GO Annotations:  Associated to 1 GO processes
GO:0019221 cytokine-mediated signaling pathway TAS
Immuno Process:  Inflammation
GO Annotations:  Associated to 1 GO processes, IEA only
click arrow to show/hide IEA associations
GO:0002438 acute inflammatory response to antigenic stimulus IEA
Primary Transduction Mechanisms Click here for help
Transducer Effector/Response
Gi/Go family Adenylyl cyclase stimulation
Adenylyl cyclase inhibition
Phospholipase C stimulation
Potassium channel
Calcium channel
Phospholipase A2 stimulation
Phospholipase D stimulation
Other - See Comments
Comments:  The following systems have also been reported to be activated following Gi/Go activation via the μ receptor:
  • Epidermal growth factor receptor transactivation and subsequent mitogen activated protein kinase ERK [12,89]
  • Jun N-terminal kinase (JNK) expression and activity [43,71,144]
  • Signal transducer and activator of transcription 3 (STAT3) [178]
  • Focal adhesion kinase [97]
  • Nuclear Ca2+/calmodulin translocation [166]
  • Phosphatidylinositol-3 kinase expression and activity [71,119].
References:  6,17,20-21,34,46,63,76,109,112,118,122,129-130,135,160,176
Secondary Transduction Mechanisms Click here for help
Transducer Effector/Response
Gq/G11 family Phospholipase C stimulation
Comments:  G16 couples to the μ opioid receptor and activates PLC.
References:  64,86
Tissue Distribution Click here for help
Immune cells: CEM x174 T/B lymphocytes, Raji B cells, CD4+, monocytes/macrophages, neutrophils.