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M1 receptor

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Target not currently curated in GtoImmuPdb

Target id: 13

Nomenclature: M1 receptor

Family: Acetylcholine receptors (muscarinic)

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 7 460 11q12.3 CHRM1 cholinergic receptor muscarinic 1 12,101
Mouse 7 460 19 A Chrm1 cholinergic receptor, muscarinic 1, CNS 87,111
Rat 7 460 1q43 Chrm1 cholinergic receptor, muscarinic 1 67,99,119,127
Previous and Unofficial Names Click here for help
M1 muscarinic acetylcholine receptor | Chrm-1 | M1R | cholinergic receptor, muscarinic 1 | cholinergic receptor | cholinergic receptor, muscarinic 1, CNS
Database Links Click here for help
Specialist databases
GPCRDB acm1_human (Hs), acm1_mouse (Mm), acm1_rat (Rn)
Other databases
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 human M1 muscarinic acetylcholine receptor bound to antagonist tiotropium.
PDB Id:  5CXV
Ligand:  tiotropium
Resolution:  2.7Å
Species:  Human
References:  126
Natural/Endogenous Ligands Click here for help
acetylcholine

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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
NNC 11-1585 Small molecule or natural product Click here for species-specific activity table Hs Full agonist 9.9 pKi 25
pKi 9.9 [25]
NNC 11-1607 Small molecule or natural product Click here for species-specific activity table Hs Full agonist 8.6 pKi 25
pKi 8.6 [25]
pentylthio-TZTP Small molecule or natural product Click here for species-specific activity table Hs Full agonist 8.6 pKi 61
pKi 8.6 [61]
NNC 11-1314 Small molecule or natural product Click here for species-specific activity table Hs Full agonist 7.4 pKi 25
pKi 7.4 [25]
xanomeline Small molecule or natural product Click here for species-specific activity table Hs Partial agonist 6.7 – 7.9 pKi 26,62,134,146
pKi 6.7 – 7.9 [26,62,134,146]
sabcomeline Small molecule or natural product Click here for species-specific activity table Hs Partial agonist 6.7 pKi 146
pKi 6.7 [146]
arecaidine propargyl ester Small molecule or natural product Click here for species-specific activity table Hs Full agonist 6.4 pKi 61
pKi 6.4 [61]
LY593093 Small molecule or natural product Hs Partial agonist 6.2 pKi 136
pKi 6.2 [136]
AC-42 Small molecule or natural product Hs Full agonist 6.2 pKi 71
pKi 6.2 [71]
oxotremorine Small molecule or natural product Click here for species-specific activity table Rn Partial agonist 6.0 pKi 89
pKi 6.0 [89]
arecoline Small molecule or natural product Click here for species-specific activity table Hs Full agonist 5.7 pKi 61
pKi 5.7 [61]
oxotremorine-M Small molecule or natural product Rn Full agonist 5.6 pKi 89
pKi 5.6 [89]
oxotremorine Small molecule or natural product Click here for species-specific activity table Hs Partial agonist 5.5 pKi 61
pKi 5.5 [61]
cevimeline Small molecule or natural product Approved drug Click here for species-specific activity table Hs Agonist 5.3 pKi 80
pKi 5.3 (Ki 4.85x10-6 M) [80]
Description: Displacement of [3H]QNB from cloned receptor.
arecoline Small molecule or natural product Rn Partial agonist 5.3 pKi 89
pKi 5.3 [89]
McN-A-343 Small molecule or natural product Click here for species-specific activity table Rn Partial agonist 5.1 pKi 89
pKi 5.1 [89]
oxotremorine-M Small molecule or natural product Click here for species-specific activity table Hs Full agonist 5.1 pKi 61
pKi 5.1 [61]
pilocarpine Small molecule or natural product Approved drug Click here for species-specific activity table Ligand has a PDB structure Hs Partial agonist 5.1 pKi 61
pKi 5.1 [61]
McN-A-343 Small molecule or natural product Click here for species-specific activity table Hs Partial agonist 4.8 – 5.2 pKi 106
pKi 4.8 – 5.2 [106]
acetylcholine Small molecule or natural product Click here for species-specific activity table Ligand is endogenous in the given species Ligand has a PDB structure Rn Full agonist 5.0 pKi 24
pKi 5.0 [24]
pilocarpine Small molecule or natural product Approved drug Ligand has a PDB structure Rn Partial agonist 4.9 pKi 89
pKi 4.9 [89]
milameline Small molecule or natural product Click here for species-specific activity table Hs Partial agonist 4.8 pKi 146
pKi 4.8 [146]
acetylcholine Small molecule or natural product Click here for species-specific activity table Ligand is endogenous in the given species Ligand has a PDB structure Hs Full agonist 4.3 – 4.9 pKi 61,73
pKi 4.3 – 4.9 [61,73]
methylfurmethide Small molecule or natural product Click here for species-specific activity table Hs Full agonist 4.6 pKi 61
pKi 4.6 [61]
(-)-YM796 Small molecule or natural product Hs Partial agonist 4.3 – 4.8 pKi 137
pKi 4.3 – 4.8 [137]
(±)YM796 Small molecule or natural product Hs Partial agonist 4.1 – 4.7 pKi 137
pKi 4.1 – 4.7 [137]
carbachol Small molecule or natural product Approved drug Click here for species-specific activity table Ligand has a PDB structure Hs Full agonist 3.2 – 5.3 pKi 26,61,146
pKi 3.2 – 5.3 [26,61,146]
furtrethonium Small molecule or natural product Click here for species-specific activity table Hs Full agonist 4.1 pKi 61
pKi 4.1 [61]
bethanechol Small molecule or natural product Approved drug Click here for species-specific activity table Hs Full agonist 4.0 pKi 61
pKi 4.0 [61]
carbachol Small molecule or natural product Approved drug Click here for species-specific activity table Ligand has a PDB structure Rn Full agonist 3.9 pKi 24
pKi 3.9 [24]
bethanechol Small molecule or natural product Approved drug Rn Full agonist 3.7 pKi 89
pKi 3.7 [89]
AZD6088 Small molecule or natural product Primary target of this compound Hs Partial agonist 8.3 pEC50 93
pEC50 8.3 (EC50 5x10-9 M) [93]
methacholine Small molecule or natural product Approved drug Click here for species-specific activity table Immunopharmacology Ligand Rn Agonist 6.4 pEC50 98
pEC50 6.4 (EC50 4x10-7 M) [98]
(+)-aceclidine Small molecule or natural product Click here for species-specific activity table Hs Full agonist 5.4 pEC50 33
pEC50 5.4 [33]
(-)-aceclidine Small molecule or natural product Click here for species-specific activity table Hs Partial agonist 5.0 pEC50 33
pEC50 5.0 [33]
[11C]butylthio-TZTP Small molecule or natural product Ligand is labelled Ligand is radioactive Hs Full agonist - - 36
[36]
[11C]xanomeline Small molecule or natural product Ligand is labelled Ligand is radioactive Hs Full agonist - - 36
[36]
SPP1 Small molecule or natural product N/A Agonist - - 15
[15]
View species-specific agonist tables
Agonist Comments
Please consult references [17,75,106,132,143] for further details of the activity of some of the ligands in this list.

Pilocarpine has been found to be a partial agonist [75,106,143] as well as a full agonist [132] at the M1 receptor; oxotremorine has also been found to be a partial agonist [75,106,132] as well as a full agonist [106] at the M1 receptor.
Antagonists
Key to terms and symbols View all chemical structures Click column headers to sort
Ligand Sp. Action Value Parameter Reference
[3H]QNB Small molecule or natural product Click here for species-specific activity table Ligand is labelled Ligand is radioactive Hs Antagonist 10.6 – 10.8 pKd 27,101
pKd 10.6 – 10.8 (Kd 2.51x10-11 – 1.58x10-11 M) [27,101]
Cy3B-telenzepine Small molecule or natural product Click here for species-specific activity table Ligand is labelled Hs Antagonist 10.5 pKd 54
pKd 10.5 [54]
[3H]N-methyl scopolamine Small molecule or natural product Click here for species-specific activity table Ligand is labelled Ligand is radioactive Hs Antagonist 9.4 – 10.3 pKd 23,26-27,56,61-63,65,73
pKd 9.4 – 10.3 (Kd 4.2x10-10 – 5x10-11 M) [23,26-27,56,61-63,65,73]
[3H]N-methyl scopolamine Small molecule or natural product Click here for species-specific activity table Ligand is labelled Ligand is radioactive Rn Antagonist 9.7 pKd 24,132
pKd 9.7 [24,132]
biperiden Small molecule or natural product Approved drug Primary target of this compound Click here for species-specific activity table Hs Antagonist 9.3 pKd 11
pKd 9.3 (Kd 4.8x10-10 M) [11]
Alexa-488-telenzepine Small molecule or natural product Click here for species-specific activity table Ligand is labelled Hs Antagonist 9.3 pKd 54
pKd 9.3 [54]
[3H]darifenacin Small molecule or natural product Click here for species-specific activity table Ligand is labelled Ligand is radioactive Hs Antagonist 8.8 pKd 115
pKd 8.8 [115]
[3H]pirenzepine Small molecule or natural product Ligand is labelled Ligand is radioactive Hs Antagonist 7.9 pKd 135
pKd 7.9 (Kd 1.4x10-8 M) [135]
[3H]pirenzepine Small molecule or natural product Ligand is labelled Ligand is radioactive Rn Antagonist 7.7 – 7.9 pKd 35,49
pKd 7.7 – 7.9 [35,49]
otenzepad Small molecule or natural product Click here for species-specific activity table Hs Antagonist 6.2 pKd 34
pKd 6.2 [34]
N-methyl scopolamine Small molecule or natural product Approved drug Primary target of this compound Click here for species-specific activity table Hs Antagonist 9.9 pKi 38
pKi 9.9 [38]
umeclidinium Small molecule or natural product Approved drug Click here for species-specific activity table Immunopharmacology Ligand Hs Antagonist 9.8 pKi 69,109
pKi 9.8 (Ki 1.6x10-10 M) [69,109]
propantheline Small molecule or natural product Approved drug Primary target of this compound Click here for species-specific activity table Hs Antagonist 9.7 pKi 58
pKi 9.7 [58]
AE9C90CB Small molecule or natural product Click here for species-specific activity table Hs Antagonist 9.7 pKi 114
pKi 9.7 [114]
tiotropium Small molecule or natural product Approved drug Click here for species-specific activity table Immunopharmacology Ligand Hs Antagonist 9.6 pKi 31
pKi 9.6 [31]
[3H](+)telenzepine Small molecule or natural product Ligand is labelled Ligand is radioactive Rn Antagonist 9.4 pKi 35
pKi 9.4 [35]
revefenacin Small molecule or natural product Approved drug Click here for species-specific activity table Hs Antagonist 9.4 pKi 53
pKi 9.4 (Ki 4.17x10-10 M) [53]
Description: Determined from a radioligand binding assay using membranes from CHO‐K1 cells expressing the hM1 receptor, and displacement of [3H]NMS tracer.
atropine Small molecule or natural product Approved drug Click here for species-specific activity table Rn Antagonist 9.0 – 9.7 pKi 18,24,64
pKi 9.0 – 9.7 [18,24,64]
ipratropium Small molecule or natural product Approved drug Click here for species-specific activity table Immunopharmacology Ligand Hs Antagonist 9.3 pKi 56
pKi 9.3 [56]
4-DAMP Small molecule or natural product Click here for species-specific activity table Hs Antagonist 9.2 pKi 32
pKi 9.2 [32]
dicyclomine Small molecule or natural product Approved drug Primary target of this compound Click here for species-specific activity table Hs Antagonist 9.1 pKi 5
pKi 9.1 (Ki 8.3x10-10 M) [5]
atropine Small molecule or natural product Approved drug Primary target of this compound Click here for species-specific activity table Hs Antagonist 8.5 – 9.6 pKi 26,38,56,58,101,115
pKi 8.5 – 9.6 [26,38,56,58,101,115]
benzatropine Small molecule or natural product Approved drug Click here for species-specific activity table Ligand has a PDB structure Rn Antagonist 9.0 pKi 95
pKi 9.0 (Ki 9.5x10-10 M) [95]
Description: Displacement binding experiment using homogenised rat caudate putamen.
scopolamine Small molecule or natural product Approved drug Primary target of this compound Click here for species-specific activity table Hs Antagonist 9.0 pKi 58
pKi 9.0 [58]
4-DAMP Small molecule or natural product Click here for species-specific activity table Rn Antagonist 8.9 pKi 64
pKi 8.9 [64]
trihexyphenidyl Small molecule or natural product Approved drug Primary target of this compound Hs Antagonist 8.9 pKi 5
pKi 8.9 (Ki 1.35x10-9 M) [5]
tripitramine Small molecule or natural product Click here for species-specific activity table Hs Antagonist 8.8 pKi 83
pKi 8.8 [83]
silahexocyclium Small molecule or natural product Rn Antagonist 8.7 pKi 18
pKi 8.7 [18]
UH-AH 37 Small molecule or natural product Click here for species-specific activity table Hs Antagonist 8.6 – 8.7 pKi 43,142
pKi 8.6 – 8.7 [43,142]
hexocyclium Small molecule or natural product Rn Antagonist 8.6 pKi 18
pKi 8.6 [18]
oxybutynin Small molecule or natural product Approved drug Primary target of this compound Click here for species-specific activity table Hs Antagonist 8.6 pKi 30,59,114
pKi 8.6 (Ki 2.4x10-9 M) [30,59,114]
tolterodine Small molecule or natural product Approved drug Click here for species-specific activity table Hs Antagonist 8.5 – 8.7 pKi 43,114
pKi 8.5 – 8.7 [43,114]
ethopropazine Small molecule or natural product Approved drug Click here for species-specific activity table Rn Antagonist 8.5 pKi 19
pKi 8.5 (Ki 3.1x10-9 M) [19]
Description: Displacement of [H]QNB binding in rat forebrain brain homogenate.
oxybutynin Small molecule or natural product Approved drug Rn Antagonist 8.2 pKi 94
pKi 8.2 [94]
pirenzepine Small molecule or natural product Approved drug Primary target of this compound Click here for species-specific activity table Hs Antagonist 7.8 – 8.3 pKi 18,32,52,58,63,142
pKi 7.8 – 8.3 [18,32,52,58,63,142]
hexahydrodifenidol Small molecule or natural product Rn Antagonist 8.0 pKi 18
pKi 8.0 [18]
solifenacin Small molecule or natural product Approved drug Rn Antagonist 8.0 pKi 94
pKi 8.0 [94]
darifenacin Small molecule or natural product Approved drug Click here for species-specific activity table Hs Antagonist 7.5 – 8.3 pKi 43,52,56,59,114
pKi 7.5 – 8.3 [43,52,56,59,114]
pirenzepine Small molecule or natural product Approved drug Click here for species-specific activity table Rn Antagonist 7.8 – 7.9 pKi 18,64
pKi 7.8 – 7.9 [18,64]
amitriptyline 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 7.8 pKi 118
pKi 7.8 (Ki 1.47x10-8 M) [118]
methoctramine Small molecule or natural product Click here for species-specific activity table Rn Antagonist 7.8 pKi 18
pKi 7.8 [18]
VU0255035 Small molecule or natural product Click here for species-specific activity table Hs Antagonist 7.8 pKi 112
pKi 7.8 (Ki 1.487x10-8 M) [112]
dosulepin Small molecule or natural product Approved drug Click here for species-specific activity table Hs Antagonist 7.7 pKi 118
pKi 7.7 (Ki 1.8x10-8 M) [118]
hexahydrosiladifenidol Small molecule or natural product Click here for species-specific activity table Hs Antagonist 7.7 pKi 34
pKi 7.7 [34]
hexahydrosiladifenidol Small molecule or natural product Click here for species-specific activity table Rn Antagonist 7.4 – 7.9 pKi 18,64
pKi 7.4 – 7.9 [18,64]
solifenacin Small molecule or natural product Approved drug Click here for species-specific activity table Hs Antagonist 7.6 pKi 59,114
pKi 7.6 [59,114]
AFDX384 Small molecule or natural product Click here for species-specific activity table Hs Antagonist 7.5 pKi 32
pKi 7.5 [32]
p-F-HHSiD Small molecule or natural product Click here for species-specific activity table Hs Antagonist 7.1 – 7.8 pKi 34,58
pKi 7.1 – 7.8 [34,58]
muscarinic toxin 1 Peptide Click here for species-specific activity table Hs Antagonist 7.3 – 7.6 pKi 38,50
pKi 7.3 – 7.6 [38,50]
guanylpirenzepine Small molecule or natural product Click here for species-specific activity table Rn Antagonist 7.3 – 7.6 pKi 3,131
pKi 7.3 – 7.6 [3,131]
AQ-RA 741 Small molecule or natural product Click here for species-specific activity table Hs Antagonist 7.2 – 7.5 pKi 32,43
pKi 7.2 – 7.5 [32,43]
muscarinic toxin 3 Peptide Click here for species-specific activity table Hs Antagonist 7.1 pKi 63
pKi 7.1 [63]
BODIPY-pirenzepine Small molecule or natural product Ligand is labelled Hs Antagonist 7.0 pKi 60
pKi 7.0 [60]
methoctramine Small molecule or natural product Click here for species-specific activity table Hs Antagonist 6.6 – 7.3 pKi 32,34,52,115
pKi 6.6 – 7.3 [32,34,52,115]
himbacine Small molecule or natural product Click here for species-specific activity table Hs Antagonist 6.7 – 7.1 pKi 32,63,91
pKi 6.7 – 7.1 [32,63,91]
(S)-dimetindene Small molecule or natural product Click here for species-specific activity table Immunopharmacology Ligand Hs Antagonist 6.7 pKi 21
pKi 6.7 (Ki 1.906x10-7 M) [21]
Description: Binding to hM1 receptors expressed in CHO cells.
muscarinic toxin 2 Peptide Click here for species-specific activity table Hs Antagonist 6.4 pKi 50
pKi 6.4 [50]
otenzepad Small molecule or natural product Click here for species-specific activity table Rn Antagonist 5.9 – 6.3 pKi 18,64
pKi 5.9 – 6.3 [18,64]
lithocholylcholine Small molecule or natural product Click here for species-specific activity table Rn Antagonist 5.6 pKi 24
pKi 5.6 [24]
ML381 Small molecule or natural product Click here for species-specific activity table Hs Antagonist <5.0 pKi 40
pKi <5.0 (Ki >1x10-5 M) [40]
glycopyrrolate Small molecule or natural product Approved drug Primary target of this compound Click here for species-specific activity table Immunopharmacology Ligand Hs Antagonist 9.9 pIC50 120
pIC50 9.9 (IC50 1.26x10-10 M) [120]
Description: Assay uses glycopyrronium bromide
aclidinium Small molecule or natural product Approved drug Click here for species-specific activity table Hs Antagonist 9.9 pIC50 104
pIC50 9.9 (IC50 1.4x10-10 M) [104]
Description: Human M1 receptors expressed in CHO-K1 cells
solifenacin Small molecule or natural product Approved drug Click here for species-specific activity table Hs Antagonist 7.2 pIC50 103
pIC50 7.2 (IC50 6.35x10-8 M) [103]
[18F](R,R)-quinuclidinyl-4-fluoromethyl-benzilate Small molecule or natural product Ligand is labelled Ligand is radioactive Rn Antagonist - - 66
[66]
View species-specific antagonist tables
Antagonist Comments
Recombinant MT7 (rMT7) is often used for bioassays due to the limited availability of the M1 muscarinic receptor-selective mamba toxin MT7 or m1-toxin 1 (rMT7 has comparable affinity for M1 [96]).

Biperiden is an approved drug antagonist of muscarinic acetylcholine receptors. We have tagged the M1 subtype as the drug's primary target as affinity is 10-fold higher at this receptor subtype [11]. Ethopropazine appears to have highest affinity for the M1 subtype in rat brain homegenates [19], so the M1 receptor is the likely primary human target of this drug.
Allosteric Modulators
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Ligand Sp. Action Value Parameter Reference
benzoquinazolinone 12 Small molecule or natural product Hs Positive 6.6 pKB 1
pKB 6.6 [1]
BQCA Small molecule or natural product Hs Positive 4.0 – 4.8 pKB 1-2,22,82
pKB 4.0 – 4.8 [1-2,22,82]
KT 5720 Small molecule or natural product Click here for species-specific activity table Hs Positive 6.4 pKd 77
pKd 6.4 (Kd 3.98x10-7 M) [77]
staurosporine Small molecule or natural product Click here for species-specific activity table Ligand has a PDB structure Hs Positive 5.9 pKd 77
pKd 5.9 [77]
Gö 7874 Small molecule or natural product Click here for species-specific activity table Hs Negative 5.8 pKd 77
pKd 5.8 [77]
WIN 51,708 Small molecule or natural product Click here for species-specific activity table Hs Negative 5.8 pKd 78
pKd 5.8 [78]
KT 5823 Small molecule or natural product Click here for species-specific activity table Hs Positive 5.7 pKd 77
pKd 5.7 [77]
WIN 62,577 Small molecule or natural product Click here for species-specific activity table Hs Negative 5.5 pKd 78
pKd 5.5 [78]
brucine Small molecule or natural product Click here for species-specific activity table Hs Positive 4.5 – 5.8 pKd 61,76
pKd 4.5 – 5.8 (Kd 3x10-5 – 1.78x10-6 M) [61,76]
K-252a Small molecule or natural product Click here for species-specific activity table Hs Positive 5.1 pKd 77
pKd 5.1 [77]
vinburnine Small molecule or natural product Click here for species-specific activity table Hs Neutral 5.1 pKd 61
pKd 5.1 [61]
alcuronium Small molecule or natural product Click here for species-specific activity table Hs Negative 5.0 pKd 61
pKd 5.0 [61]
strychnine Small molecule or natural product Click here for species-specific activity table Ligand has a PDB structure Hs Neutral 4.9 – 5.0 pKd 61,73
pKd 4.9 – 5.0 [61,73]
strychnine Small molecule or natural product Click here for species-specific activity table Ligand has a PDB structure Hs Negative 4.9 pKd 73
pKd 4.9 [73]