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μ receptor

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Target not currently curated in GtoImmuPdb

Target id: 319

Nomenclature: μ receptor

Family: Opioid receptors

Contents:

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 1 184
Mouse 7 398 10 1.85 cM Oprm1 opioid receptor, mu 1 114
Rat 7 398 1q11 Oprm1 opioid receptor, mu 1 27,47,161,183,194
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 P35372 (Hs), P42866 (Mm), P33535 (Rn)
ChEMBL Target CHEMBL233 (Hs), CHEMBL2858 (Mm), CHEMBL270 (Rn)
DrugBank Target P35372 (Hs)
Ensembl Gene ENSG00000112038 (Hs), ENSMUSG00000000766 (Mm), ENSRNOG00000018191 (Rn)
Entrez Gene 4988 (Hs), 18390 (Mm), 25601 (Rn)
Human Protein Atlas ENSG00000112038 (Hs)
KEGG Gene hsa:4988 (Hs), mmu:18390 (Mm), rno:25601 (Rn)
OMIM 600018 (Hs)
Pharos P35372 (Hs)
RefSeq Nucleotide NM_000914 (Hs), NM_001039652 (Mm), NM_013071 (Rn)
RefSeq Protein NP_000905 (Hs), NP_001034741 (Mm), NP_037203 (Rn)
SynPHARM 3941 (in complex with β-FNA)
UniProtKB P35372 (Hs), P42866 (Mm), P33535 (Rn)
Wikipedia OPRM1 (Hs)
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:  102
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:  86
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)

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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 143
⤷ pKd 9.2 (Kd 5.7x10-10 M) [143]
ohmefentanyl Small molecule or natural product Rn Agonist 9.0 pKd 181
⤷ pKd 9.0 (Kd 9.5x10-10 M) [181]
Description: Binding affinity of [3H]ohmefentanyl
carfentanil Small molecule or natural product Click here for species-specific activity table Ligand has a PDB structure Cp Agonist 10.6 pKi 35
⤷ pKi 10.6 (Ki 2.4x10-11 M) [35]
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 166
⤷ pKi 10.0 [166]
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 49
⤷ pKi 9.9 (Ki 1.2x10-10 M) [49]
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 177
⤷ pKi 9.9 (Ki 1.38x10-10 M) [177]
etonitazene Small molecule or natural product Click here for species-specific activity table Hs Full agonist 9.7 pKi 166
⤷ pKi 9.7 [166]
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 185
⤷ pKi 9.6 (Ki 2.8x10-10 M) [185]
ethylketocyclazocine Small molecule or natural product Click here for species-specific activity table Hs Full agonist 9.5 pKi 166
⤷ pKi 9.5 [166]
etorphine Small molecule or natural product Click here for species-specific activity table Hs Full agonist 9.5 pKi 166
⤷ pKi 9.5 [166]
fentanyl Small molecule or natural product Approved drug Ligand has a PDB structure Rn Full agonist 9.4 pKi 143
⤷ pKi 9.4 [143]
DAMGO Peptide Click here for species-specific activity table Hs Full agonist 9.3 pKi 63,166
⤷ pKi 9.3 [63,166]
DC-1-76.2 Small molecule or natural product Mm Agonist 9.3 pKi 22
⤷ pKi 9.3 (Ki 5x10-10 M) [22]
Description: Binding affinity determined in a radioligand membrane binding assay, displacing [3H]naloxone
loperamide Small molecule or natural product Approved drug Primary target of this compound Hs Agonist 9.3 pKi 28
⤷ pKi 9.3 (Ki 5.3x10-10 M) [28]
DC 128.1 Small molecule or natural product Mm Agonist 9.3 pKi 22
⤷ pKi 9.3 (Ki 5.6x10-10 M) [22]
Description: Binding affinity determined in a radioligand membrane binding assay, displacing [3H]naloxone
EWB-3-14 Small molecule or natural product Hs Agonist 9.2 pKi 69
⤷ pKi 9.2 (Ki 6x10-10 M) [69]
Description: Displacement of [125I]Ioxycodone from human mu opioid receptor expressed in CHO cells
EG-1-230 Small molecule or natural product Hs Agonist 9.2 pKi 69
⤷ pKi 9.2 (Ki 6x10-10 M) [69]
Description: Displacement of [125I]Ioxycodone from human mu opioid receptor
(-)-methadone Small molecule or natural product Click here for species-specific activity table Hs Full agonist 9.2 pKi 166
⤷ pKi 9.2 [166]
[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 143
⤷ pKi 9.2 [143]
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 166
⤷ pKi 9.2 [166]
cebranopadol Small molecule or natural product Click here for species-specific activity table Hs Agonist 9.1 pKi 97
⤷ pKi 9.1 (Ki 7x10-10 M) [97]
Description: Radioligand binding assay
sufentanil Small molecule or natural product Approved drug Rn Full agonist 9.1 pKi 188
⤷ pKi 9.1 (Ki 7.7x10-10 M) [188]
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 55,166
⤷ pKi 9.0 [55,166]
β-endorphin {Sp: Human} Peptide Click here for species-specific activity table Rn Full agonist 9.0 pKi 143
⤷ pKi 9.0 [143]
PZM21 Small molecule or natural product Primary target of this compound Ligand has a PDB structure Hs Biased agonist 9.0 pKi 103
⤷ pKi 9.0 (Ki 1.1x10-9 M) [103]
bilorphin Small molecule or natural product Primary target of this compound Click here for species-specific activity table Hs Agonist 9.0 pKi 38
⤷ pKi 9.0 (Ki 1.1x10-9 M) [38]
dihydromorphine Small molecule or natural product Click here for species-specific activity table Hs Full agonist 8.8 pKi 166
⤷ pKi 8.8 [166]
dynorphin-(1-11) Peptide Click here for species-specific activity table Hs Full agonist 8.8 pKi 166
⤷ pKi 8.8 [166]
normorphine Small molecule or natural product Click here for species-specific activity table Hs Full agonist 8.8 pKi 166
⤷ pKi 8.8 [166]
nalbuphine 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 185
⤷ pKi 8.8 (Ki 1.6x10-9 M) [185]
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 166
⤷ pKi 8.8 [166]
eluxadoline Small molecule or natural product Approved drug Hs Agonist 8.8 pKi 18
⤷ pKi 8.8 (Ki 1.7x10-9 M) [18]
DC-1-90.2 Small molecule or natural product Mm Agonist 8.7 pKi 22
⤷ pKi 8.7 (Ki 1.83x10-9 M) [22]
Description: Binding affinity determined in a radioligand membrane binding assay, displacing [3H]naloxone
DC-1-76.1 Small molecule or natural product Mm Agonist 8.7 pKi 22
⤷ pKi 8.7 (Ki 1.91x10-9 M) [22]
Description: Binding affinity determined in a radioligand membrane binding assay, displacing [3H]naloxone
DADLE Peptide Click here for species-specific activity table Hs Full agonist 8.7 pKi 166
⤷ pKi 8.7 [166]
DAMGO Peptide Click here for species-specific activity table Rn Full agonist 8.7 pKi 143
⤷ pKi 8.7 [143]
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 128
⤷ pKi 8.7 (Ki 2x10-9 M) [128]
BU08028 Small molecule or natural product Click here for species-specific activity table Hs Partial agonist 8.7 pKi 81
⤷ pKi 8.7 (Ki 2.14x10-9 M) [81]
cebranopadol Small molecule or natural product Click here for species-specific activity table Rn Agonist 8.6 pKi 97
⤷ pKi 8.6 (Ki 2.4x10-9 M) [97]
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 166
⤷ pKi 8.5 [166]
endomorphin-2 {Sp: Human} Peptide Rn Full agonist 8.5 pKi 193
⤷ pKi 8.5 (Ki 3.24x10-9 M) [193]
(-)-pentazocine Small molecule or natural product Approved drug Click here for species-specific activity table Hs Partial agonist 8.4 pKi 166
⤷ pKi 8.4 [166]
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 166
⤷ pKi 8.4 [166]
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 166
⤷ pKi 8.3 [166]
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 57,193
⤷ pKi 8.3 (Ki 5.01x10-9 M) [57,193]
DSLET Peptide Click here for species-specific activity table Hs Full agonist 8.2 pKi 166
⤷ pKi 8.2 [166]
PL017 Peptide Hs Full agonist 8.2 pKi 25,166
⤷ pKi 8.2 [25,166]
etonitazene Small molecule or natural product Rn Full agonist 8.2 pKi 54
⤷ pKi 8.2 (Ki 6.6x10-9 M) [54]
Description: Binding affinity determined in radioligand displacement assay using rat brain and [3H]DAMGO as tracer
[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 166
⤷ pKi 8.1 [166]
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 166
⤷ pKi 8.1 [166]
UFP-512 Small molecule or natural product Click here for species-specific activity table Hs Agonist 8.0 pKi 176
⤷ pKi 8.0 [176]
Description: Measuring displacement of [3H]-diprenorphine in vitro
isotonitazene Small molecule or natural product Rn Full agonist 7.9 pKi 174
⤷ pKi 7.9 (Ki 1.12x10-8 M) [174]
Description: Binding affinity in rat brain
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 143
⤷ pKi 7.9 [143]
BW373U86 Small molecule or natural product Click here for species-specific activity table Rn Agonist 7.8 pKi 24
⤷ pKi 7.8 (Ki 1.5x10-8 M) [24]
UFP-505 Small molecule or natural product Click here for species-specific activity table Hs Agonist 7.8 pKi 40-41
⤷ pKi 7.8 [40-41]
ADL5747 Small molecule or natural product Click here for species-specific activity table Hs Agonist 7.7 pKi 92
⤷ pKi 7.7 (Ki 1.8x10-8 M) [92]
SRI22141 Small molecule or natural product Click here for species-specific activity table Hs Agonist 7.7 pKi 94
⤷ pKi 7.7 (Ki 1.97x10-8 M) [94]
Description: Binding affinity
brorphine Small molecule or natural product Rn Agonist 7.6 pKi 174
⤷ pKi 7.6 (Ki 2.42x10-8 M) [174]
Description: Binding affinity for rat brain MOR, determined in a radiologand displacement assay
ADL5859 Small molecule or natural product Click here for species-specific activity table Hs Agonist 7.5 pKi 91
⤷ pKi 7.5 (Ki 3.2x10-8 M) [91]
ICI-199441 Small molecule or natural product Click here for species-specific activity table Hs Agonist 7.3 pKi 88
⤷ pKi 7.3 (Ki 5.3x10-8 M) [88]
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 175
⤷ pKi 7.2 (Ki 6.5x10-8 M) [175]
Description: Radioligand binding assay
SR16835 Small molecule or natural product Click here for species-specific activity table Hs Agonist 7.1 pKi 167
⤷ pKi 7.1 (Ki 7.99x10-8 M) [167]
Description: Radioligand binding assay
codeine Small molecule or natural product Approved drug Primary target of this compound Hs Full agonist 6.9 pKi 166
⤷ pKi 6.9 [166]
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 169
⤷ pKi 6.8 (Ki 1.6x10-7 M) [169]
oxycodegol Small molecule or natural product Click here for species-specific activity table Hs Agonist 6.6 pKi 117
⤷ pKi 6.6 (Ki 2.37x10-7 M) [117]
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 91
⤷ pKi 6.6 (Ki 2.6x10-7 M) [91]
HS665 Small molecule or natural product Click here for species-specific activity table Hs Agonist 6.3 pKi 156
⤷ pKi 6.3 (Ki 5.42x10-7 M) [156]
compound 3 [PMID: 23134120] Small molecule or natural product Click here for species-specific activity table Hs Agonist 6.1 pKi 156
⤷ pKi 6.1 (Ki 8.26x10-7 M) [156]
tramadol Small molecule or natural product Approved drug Click here for species-specific activity table Hs Agonist 5.8 pKi 185
⤷ pKi 5.8 (Ki 1.6x10-6 M) [185]
Description: Displacement of the mu aginist peptide DAMGO from the mu receptor expressed in CHO cells.
etonitazene Small molecule or natural product Click here for species-specific activity table Hs Full agonist 10.5 pEC50 54
⤷ pEC50 10.5 (EC50 3x10-11 M) [54]
Description: Potency determined as inhibition of cAMP accumulation in a Gi-cAMP assay
isotonitazene Small molecule or natural product Hs Full agonist 10.3 pEC50 174
⤷ pEC50 10.3 (EC50 5x10-11 M) [174]
Description: Potency determined in a cAMP accumulation assay in HEK cells expressing hMOR
lofentanil Small molecule or natural product Hs Agonist 9.9 pEC50 142
⤷ pEC50 9.9 [142]
Description: Determined using a NanoBiT based G protein dissociation assay
SRI22141 Small molecule or natural product Click here for species-specific activity table Hs Agonist 9.7 pEC50 94
⤷ pEC50 9.7 (EC50 2x10-10 M) [94]
Description: Potency in a 35S-GTPγS assay
atoxifent Small molecule or natural product Click here for species-specific activity table Hs Agonist 9.4 pEC50 178
⤷ pEC50 9.4 (EC50 3.9x10-10 M) [178]
mitragynine Small molecule or natural product Hs Agonist 9.3 pEC50 21
⤷ pEC50 9.3 (EC50 5x10-10 M) [21]
Description: Determined as inhibition of forskolin-stimulated cAMP accumulation in HEK293T cells expressing human mu opioid receptor
brorphine Small molecule or natural product Hs Agonist 8.3 – 8.7 pEC50 80,174
⤷ pEC50 8.7 (EC50 2.06x10-9 M) [174]
Description: Potency determined in a cAMP accumulation assay in HEK cells expressing hMOR
pEC50 8.3 (EC50 4.8x10-9 M) [80]
Description: Potency in a GTPγS binding assay
PZM21 Small molecule or natural product Primary target of this compound Ligand has a PDB structure Hs Biased agonist 8.3 pEC50 103
⤷ pEC50 8.3 (EC50 4.6x10-9 M) [103]
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
mitragynine Small molecule or natural product Mm Agonist 6.7 pEC50 171
⤷ pEC50 6.7 (EC50 2.03x10-7 M) [171]
Description: Determined as agonist-induced [35S]GTPγS binding in CHO cells expressing mouse mu opioid receptor
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
thebaine Small molecule or natural product Ligand has a PDB structure Hs Partial agonist 5.3 pEC50 129
⤷ pEC50 5.3 (EC50 5.6x10-6 M) [129]
Description: Measuring ligand-indiced activation of Gi signalling in a FRET-based 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 65
⤷ pIC50 9.9 (IC50 1.3x10-10 M) [65]
BU72 Small molecule or natural product Ligand has a PDB structure Cp Agonist 9.8 pIC50 71
⤷ pIC50 9.8 (IC50 1.5x10-10 M) [71]
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 140
⤷ pIC50 8.4 (IC50 4.1x10-9 M) [140]
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 140
⤷ pIC50 6.5 (IC50 3.15x10-7 M) [140]
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 - - 66
⤷ [66]
U-47700 Small molecule or natural product Rn Agonist - - 29
⤷ [29]
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 [166].

It is still unclear whether endomorphins are endogenous. Morphine occurs endogenously [139].

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 [128]. Similarly, we have tagged the μ receptor as the primary target of hydromorphone [185].

Methadone is selective for the μ receptor: comparable IC50s at the κ and δ receptors are 512 and 1090nM respectively [140].

[11C]carfentanil (PubChem CID 449698) binds the human μ receptor with a Ki of 0.07 nM, in a [3H]DAMGO displacement assay [67].
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 143
⤷ pKd 10.1 (Kd 7.94x10-11 M) [143]
[3H]naloxone Small molecule or natural product Ligand is labelled Ligand is radioactive Ligand has a PDB structure Rn Antagonist 8.6 – 9.0 pKd 131
⤷ pKd 8.6 – 9.0 (Kd 2.8x10-9 – 1x10-9 M) [131]
Description: CHO and BHK cell lines stably expressing the rat μ receptor
naloxonazine Small molecule or natural product Mm Antagonist 10.3 pKi 143
⤷ pKi 10.3 [143]
samidorphan Small molecule or natural product Approved drug Click here for species-specific activity table Hs Antagonist 10.3 pKi 186
⤷ pKi 10.3 (Ki 5.2x10-11 M) [186]
diprenorphine Small molecule or natural product Mm Antagonist 10.1 pKi 143
⤷ pKi 10.1 [143]
quadazocine Small molecule or natural product Click here for species-specific activity table Hs Antagonist 10.0 pKi 166
⤷ pKi 10.0 [166]
(-)-bremazocine Small molecule or natural product Click here for species-specific activity table Hs Antagonist 9.7 pKi 166
⤷ pKi 9.7 [166]
CTOP Peptide Hs Antagonist 9.7 pKi 59,143
⤷ pKi 9.7 [59,143]
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 166
⤷ pKi 9.5 [166]
β-FNA Small molecule or natural product Click here for species-specific activity table Hs Antagonist 9.5 pKi 166
⤷ pKi 9.5 [166]
β-FNA Small molecule or natural product Mm Antagonist 9.5 pKi 143
⤷ pKi 9.5 [143]
NFP Small molecule or natural product Click here for species-specific activity table Hs Antagonist 9.4 pKi 196
⤷ pKi 9.4 (Ki 3.6x10-10 M) [196]
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 79,166
⤷ pKi 9.1 – 9.7 (Ki 7.1x10-10 – 1.99x10-10 M) [79,166]
GSK1521498 Small molecule or natural product Primary target of this compound Hs Antagonist 9.4 pKi 79
⤷ pKi 9.4 (Ki 4.17x10-10 M) [79]
alvimopan 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 Antagonist 9.3 pKi 90
⤷ pKi 9.3 (Ki 4.7x10-10 M) peripheral [90]
diprenorphine Small molecule or natural product Click here for species-specific activity table Hs Antagonist 9.1 pKi 166
⤷ pKi 9.1 [166]
levallorphan Small molecule or natural product Approved drug Primary target of this compound Hs Antagonist 8.8 – 9.3 pKi 101
⤷ pKi 8.8 – 9.3 (Ki 1.69x10-9 – 4.8x10-10 M) [101]
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 Ligand has a PDB structure Mm Antagonist 9.0 pKi 143
⤷ pKi 9.0 [143]
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 73
⤷ pKi 8.9 (Ki 1.13x10-9 M) [73]
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 166
⤷ pKi 8.9 [166]
naloxone Small molecule or natural product Approved drug Click here for species-specific activity table Ligand has a PDB structure Hs Antagonist 8.9 pKi 166
⤷ pKi 8.9 [166]
BNTX Small molecule or natural product Click here for species-specific activity table Hs Antagonist 8.8 pKi 166
⤷ pKi 8.8 [166]
AT-076 Small molecule or natural product Click here for species-specific activity table Hs Antagonist 8.8 pKi 166,195