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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

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 1 181
Mouse 7 398 10 1.85 cM Oprm1 opioid receptor, mu 1 114
Rat 7 398 1q11 Oprm1 opioid receptor, mu 1 27,47,160,180,191
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:  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 142
pKd 9.2 (Kd 5.7x10-10 M) [142]
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 165
pKi 10.0 [165]
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 176
pKi 9.9 (Ki 1.38x10-10 M) [176]
etonitazene Small molecule or natural product Click here for species-specific activity table Hs Full agonist 9.7 pKi 165
pKi 9.7 [165]
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 182
pKi 9.6 (Ki 2.8x10-10 M) [182]
ethylketocyclazocine Small molecule or natural product Click here for species-specific activity table Hs Full agonist 9.5 pKi 165
pKi 9.5 [165]
etorphine Small molecule or natural product Click here for species-specific activity table Hs Full agonist 9.5 pKi 165
pKi 9.5 [165]
fentanyl Small molecule or natural product Approved drug Ligand has a PDB structure Rn Full agonist 9.4 pKi 142
pKi 9.4 [142]
DAMGO Peptide Click here for species-specific activity table Hs Full agonist 9.3 pKi 63,165
pKi 9.3 [63,165]
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 165
pKi 9.2 [165]
[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 142
pKi 9.2 [142]
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 165
pKi 9.2 [165]
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 185
pKi 9.1 (Ki 7.7x10-10 M) [185]
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 55,165
pKi 9.0 [55,165]
β-endorphin {Sp: Human} Peptide Click here for species-specific activity table Rn Full agonist 9.0 pKi 142
pKi 9.0 [142]
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 165
pKi 8.8 [165]
dynorphin-(1-11) Peptide Click here for species-specific activity table Hs Full agonist 8.8 pKi 165
pKi 8.8 [165]
normorphine Small molecule or natural product Click here for species-specific activity table Hs Full agonist 8.8 pKi 165
pKi 8.8 [165]
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 182
pKi 8.8 (Ki 1.6x10-9 M) [182]
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 165
pKi 8.8 [165]
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 165
pKi 8.7 [165]
DAMGO Peptide Click here for species-specific activity table Rn Full agonist 8.7 pKi 142
pKi 8.7 [142]
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 165
pKi 8.5 [165]
endomorphin-2 {Sp: Human} Peptide Ligand is endogenous in the given species Rn Full agonist 8.5 pKi 190
pKi 8.5 (Ki 3.24x10-9 M) [190]
(-)-pentazocine Small molecule or natural product Approved drug Click here for species-specific activity table Hs Partial agonist 8.4 pKi 165
pKi 8.4 [165]
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 165
pKi 8.4 [165]
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 165
pKi 8.3 [165]
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 57,190
pKi 8.3 (Ki 5.01x10-9 M) [57,190]
DSLET Peptide Click here for species-specific activity table Hs Full agonist 8.2 pKi 165
pKi 8.2 [165]
PL017 Peptide Hs Full agonist 8.2 pKi 25,165
pKi 8.2 [25,165]
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 165
pKi 8.1 [165]
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 165
pKi 8.1 [165]
UFP-512 Small molecule or natural product Click here for species-specific activity table Hs Agonist 8.0 pKi 175
pKi 8.0 [175]
Description: Measuring displacement of [3H]-diprenorphine in vitro
isotonitazene Small molecule or natural product Rn Full agonist 7.9 pKi 173
pKi 7.9 (Ki 1.12x10-8 M) [173]
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 142
pKi 7.9 [142]
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 173
pKi 7.6 (Ki 2.42x10-8 M) [173]
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 174
pKi 7.2 (Ki 6.5x10-8 M) [174]
Description: Radioligand binding assay
SR16835 Small molecule or natural product Click here for species-specific activity table Hs Agonist 7.1 pKi 166
pKi 7.1 (Ki 7.99x10-8 M) [166]
Description: Radioligand binding assay
codeine Small molecule or natural product Approved drug Primary target of this compound Hs Full agonist 6.9 pKi 165
pKi 6.9 [165]
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 168
pKi 6.8 (Ki 1.6x10-7 M) [168]
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 155
pKi 6.3 (Ki 5.42x10-7 M) [155]
compound 3 [PMID: 23134120] Small molecule or natural product Click here for species-specific activity table Hs Agonist 6.1 pKi 155
pKi 6.1 (Ki 8.26x10-7 M) [155]
tramadol Small molecule or natural product Approved drug Click here for species-specific activity table Hs Agonist 5.8 pKi 182
pKi 5.8 (Ki 1.6x10-6 M) [182]
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 173
pEC50 10.3 (EC50 5x10-11 M) [173]
Description: Potency determined in a cAMP accumulation assay in HEK cells expressing hMOR
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
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 80,173
pEC50 8.7 (EC50 2.06x10-9 M) [173]
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 170
pEC50 6.7 (EC50 2.03x10-7 M) [170]
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 [165].

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 [182].

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 142
pKd 10.1 (Kd 7.94x10-11 M) [142]
[3H]naloxone Small molecule or natural product Ligand is labelled Ligand is radioactive 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 142
pKi 10.3 [142]
samidorphan Small molecule or natural product Approved drug Click here for species-specific activity table Hs Antagonist 10.3 pKi 183
pKi 10.3 (Ki 5.2x10-11 M) [183]
diprenorphine Small molecule or natural product Mm Antagonist 10.1 pKi 142
pKi 10.1 [142]
quadazocine Small molecule or natural product Click here for species-specific activity table Hs Antagonist 10.0 pKi 165
pKi 10.0 [165]
(-)-bremazocine Small molecule or natural product Click here for species-specific activity table Hs Antagonist 9.7 pKi 165
pKi 9.7 [165]
CTOP Peptide Hs Antagonist 9.7 pKi 59,142
pKi 9.7 [59,142]
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 165
pKi 9.5 [165]
β-FNA Small molecule or natural product Click here for species-specific activity table Hs Antagonist 9.5 pKi 165
pKi 9.5 [165]
β-FNA Small molecule or natural product Mm Antagonist 9.5 pKi 142
pKi 9.5 [142]
NFP Small molecule or natural product Click here for species-specific activity table Hs Antagonist 9.4 pKi 193
pKi 9.4 (Ki 3.6x10-10 M) [193]
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 79,165
pKi 9.1 – 9.7 (Ki 7.1x10-10 – 1.99x10-10 M) [79,165]
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 165
pKi 9.1 [165]
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 Mm Antagonist 9.0 pKi 142
pKi 9.0 [142]
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 165
pKi 8.9 [165]
naloxone Small molecule or natural product Approved drug Click here for species-specific activity table Hs Antagonist 8.9 pKi 165
pKi 8.9 [165]
BNTX Small molecule or natural product Click here for species-specific activity table Hs Antagonist 8.8 pKi 165
pKi 8.8 [165]
AT-076 Small molecule or natural product Click here for species-specific activity table Hs Antagonist 8.8 pKi 165,192
pKi 8.8 (Ki 1.67x10-9 M) [165,192]
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 182
pKi 8.7 (Ki 2x10-9 M) [182]
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 25,165
pKi 8.6 [25,165]
naloxone benzoylhydrazone Small molecule or natural product Click here for species-specific activity table