Gene and Protein Information
class A G protein-coupled receptor
Species	TM	AA	Chromosomal Location	Gene Symbol	Gene Name	Reference
Human	7	479	11p11.2	CHRM4	cholinergic receptor muscarinic 4	3,36
Mouse	7	479	2 50.63 cM	Chrm4	cholinergic receptor, muscarinic 4	60
Rat	7	478	3q24	Chrm4	cholinergic receptor, muscarinic 4	47,95,109

Previous and Unofficial Names

HM3 [76-77] | Chrm-4 | cholinergic receptor, muscarinic 4 | cholinergic receptor

Database Links
Specialist databases
GPCRdb	acm4_human (Hs), acm4_mouse (Mm)
Other databases
Alphafold	P08173 (Hs), P32211 (Mm), P08485 (Rn)
ChEMBL Target	CHEMBL1821 (Hs), CHEMBL4572 (Mm), CHEMBL317 (Rn)
DrugBank Target	P08173 (Hs)
Ensembl Gene	ENSG00000180720 (Hs), ENSMUSG00000040495 (Mm), ENSRNOG00000017556 (Rn)
Entrez Gene	1132 (Hs), 12672 (Mm), 25111 (Rn)
Human Protein Atlas	ENSG00000180720 (Hs)
KEGG Gene	hsa:1132 (Hs), mmu:12672 (Mm), rno:25111 (Rn)
OMIM	118495 (Hs)
Pharos	P08173 (Hs)
RefSeq Nucleotide	NM_000741 (Hs), NM_007699 (Mm), NM_031547 (Rn)
RefSeq Protein	NP_000732 (Hs), NP_031725 (Mm), NP_113735 (Rn)
UniProtKB	P08173 (Hs), P32211 (Mm), P08485 (Rn)
Wikipedia	CHRM4 (Hs)

Selected 3D Structures
	Description:  Structure of the M4 muscarinic acetylcholine receptor (M4-mT4L) bound to tiotropium. PDB Id:  5DSG Ligand:  tiotropium Resolution:  2.6Å Species:  Human References:  93

Natural/Endogenous Ligands
acetylcholine

Download all structure-activity data for this target as a CSV file

Agonists
Key to terms and symbols	View all chemical structures	Click column headers to sort
Ligand Sp. Action Value Parameter Reference [3H]iperoxo Hs Agonist 10.1 pKd 83 ⤷ pKd 10.1 (Kd 8x10-11 M) [83] [3H]acetylcholine Hs Agonist 8.2 pKd 53 ⤷ pKd 8.2 (Kd 6.3x10-9 M) [53] pentylthio-TZTP Hs Full agonist 8.7 pKi 45 ⤷ pKi 8.7 [45] NNC 11-1585 Hs Full agonist 8.6 pKi 18 ⤷ pKi 8.6 [18] NNC 11-1607 Hs Full agonist 8.1 pKi 18 ⤷ pKi 8.1 [18] xanomeline Hs Partial agonist 7.4 – 7.7 pKi 62,78,103,110 ⤷ pKi 7.4 – 7.7 [62,78,103,110] NNC 11-1314 Hs Full agonist 7.3 pKi 18 ⤷ pKi 7.3 [18] sabcomeline Hs Partial agonist 7.2 pKi 110 ⤷ pKi 7.2 [110] McN-A-343 Hs Partial agonist 5.6 – 6.7 pKi 50 ⤷ pKi 5.6 – 6.7 [50] cevimeline Hs Agonist 6.0 pKi 59 ⤷ pKi 6.0 (Ki 1.012x10-6 M) [59] Description: Displacement of [3H]QNB from cloned receptor. arecaidine propargyl ester Hs Full agonist 5.9 pKi 45 ⤷ pKi 5.9 [45] methacholine Rn Agonist 5.8 pKi 75,80 ⤷ pKi 5.8 (Ki 1.6x10-6 M) [75,80] arecoline Hs Full agonist 5.5 pKi 45,74,80 ⤷ pKi 5.5 [45,74,80] milameline Hs Partial agonist 5.5 pKi 110 ⤷ pKi 5.5 [110] oxotremorine Hs Full agonist 5.2 pKi 45,80 ⤷ pKi 5.2 [45,80] oxotremorine-M Hs Full agonist 5.2 pKi 45 ⤷ pKi 5.2 [45] pilocarpine Hs Partial agonist 5.2 pKi 45,80 ⤷ pKi 5.2 [45,80] acetylcholine Hs Full agonist 4.5 – 5.6 pKi 45,48 ⤷ pKi 4.5 – 5.6 [45,48] methylfurmethide Hs Full agonist 4.7 pKi 45 ⤷ pKi 4.7 [45] carbachol Hs Full agonist 4.3 – 4.9 pKi 45,110 ⤷ pKi 4.3 – 4.9 [45,110] furtrethonium Hs Full agonist 4.3 pKi 45 ⤷ pKi 4.3 [45] bethanechol Hs Full agonist 4.0 pKi 45,80 ⤷ pKi 4.0 [45,80] (+)-aceclidine Hs Full agonist 5.4 pEC50 28 ⤷ pEC50 5.4 [28] (-)-aceclidine Hs Partial agonist 4.8 pEC50 28 ⤷ pEC50 4.8 [28] iperoxo Hs Agonist - - 83 ⤷ [83]
View species-specific agonist tables
Agonist Comments
The binding data for McN-A-343 [50] is found on rat striatum. Please consult references [5,54,80,102] for further details of the activity of some of the ligands in this list. McN-A-343 and pilocarpine have been found to be partial agonists [54] and full agonists [80,102] at the M4 receptor.

Antagonists
Key to terms and symbols	View all chemical structures	Click column headers to sort
Ligand Sp. Action Value Parameter Reference [3H]QNB Hs Antagonist 9.7 – 10.5 pKd 44,76 ⤷ pKd 9.7 – 10.5 (Kd 2x10-10 – 3.16x10-11 M) [44,76] [3H]N-methyl scopolamine Hs Antagonist 9.9 – 10.2 pKd 12,44-45,49,52,102 ⤷ pKd 9.9 – 10.2 (Kd 1.4x10-10 – 6x10-11 M) [12,44-45,49,52,102] [3H]AF DX-384 Hs Antagonist 8.7 pKd 13,65,98 ⤷ pKd 8.7 [13,65,98] biperiden Hs Antagonist 8.6 pKd 2 ⤷ pKd 8.6 (Kd 2.4x10-9 M) [2] otenzepad Hs Antagonist 7.0 pKd 29 ⤷ pKd 7.0 [29] tiotropium Hs Antagonist 10.2 – 10.6 pKi 90,92 ⤷ pKi 10.2 – 10.6 [90,92] 3-quinuclidinyl-benzilate Hs Antagonist 10.4 pKi 11 ⤷ pKi 10.4 (Ki 4x10-11 M) [11] umeclidinium Hs Antagonist 10.3 pKi 82 ⤷ pKi 10.3 [82] propantheline Hs Antagonist 10.2 pKi 43 ⤷ pKi 10.2 [43] aclidinium Hs Antagonist 10.0 pKi 92 ⤷ pKi 10.0 [92] oxyphenonium Hs Antagonist 9.8 pKi 11 ⤷ pKi 9.8 (Ki 1.45x10-10 M) [11] atropine Rn Antagonist 9.7 pKi 47 ⤷ pKi 9.7 [47] glycopyrrolate Hs Antagonist 9.1 – 10.0 pKi 88,90 ⤷ pKi 9.1 – 10.0 [88,90] AE9C90CB Hs Antagonist 9.5 pKi 85 ⤷ pKi 9.5 [85] mepenzolic acid Hs Antagonist 9.4 pKi 11 ⤷ pKi 9.4 (Ki 3.6x10-10 M) [11] scopolamine Hs Antagonist 9.1 – 9.5 pKi 2,43 ⤷ pKi 9.1 – 9.5 [2,43] revefenacin Hs Antagonist 9.3 pKi 40 ⤷ pKi 9.3 (Ki 5.5x10-10 M) [40] Description: Determined from a radioligand binding assay using membranes from CHO‐K1 cells expressing the hM4 receptor, and displacement of [3H]NMS tracer. ipratropium Hs Antagonist 9.2 pKi 41 ⤷ pKi 9.2 [41] 4-DAMP Rn Antagonist 9.1 pKi 47 ⤷ pKi 9.1 [47] atropine Hs Antagonist 8.7 – 9.5 pKi 20,41,43,77 ⤷ pKi 8.7 – 9.5 [20,41,43,77] 4-DAMP Hs Antagonist 8.9 pKi 26 ⤷ pKi 8.9 [26] oxybutynin Hs Antagonist 8.4 – 8.7 pKi 25,85 ⤷ pKi 8.4 – 8.7 [25,85] muscarinic toxin 3 Hs Antagonist 8.5 pKi 11 ⤷ pKi 8.5 (Ki 3x10-9 M) [11] silahexocyclium Hs Antagonist 8.5 pKi 7 ⤷ pKi 8.5 [7] tolterodine Hs Antagonist 8.3 – 8.4 pKi 33,85 ⤷ pKi 8.3 – 8.4 [33,85] UH-AH 37 Hs Antagonist 8.3 – 8.4 pKi 33,108 ⤷ pKi 8.3 – 8.4 [33,108] hexocyclium Hs Antagonist 8.3 pKi 7 ⤷ pKi 8.3 [7] dicyclomine Hs Antagonist 8.3 pKi 11 ⤷ pKi 8.3 (Ki 5x10-9 M) [11] PCS1055 Hs Antagonist 8.2 pKi 20 ⤷ pKi 8.2 [20] himbacine Hs Antagonist 7.9 – 8.4 pKi 11,26,46,64 ⤷ pKi 8.4 (Ki 4x10-9 M) [11] pKi 7.9 – 8.2 [26,46,64] amitriptyline Hs Antagonist 8.1 pKi 86 ⤷ pKi 8.1 (Ki 7.2x10-9 M) [86] AQ-RA 741 Hs Antagonist 7.8 – 8.2 pKi 26,33 ⤷ pKi 7.8 – 8.2 [26,33] tripitramine Hs Antagonist 7.9 pKi 66 ⤷ pKi 7.9 [66] darifenacin Hs Antagonist 7.3 – 8.1 pKi 33,41,85 ⤷ pKi 7.3 – 8.1 [33,41,85] hexahydrosiladifenidol Rn Antagonist 7.7 pKi 47 ⤷ pKi 7.7 [47] AFDX384 Hs Antagonist 7.3 – 8.0 pKi 20,26 ⤷ pKi 7.3 – 8.0 [20,26] pirenzepine Hs Antagonist 7.0 – 8.1 pKi 11,26,39,43,46,108 ⤷ pKi 8.1 (Ki 8x10-9 M) [11] pKi 7.0 – 7.6 [26,39,43,46,108] PD 102807 Hs Antagonist 7.4 – 7.6 pKi 20,71 ⤷ pKi 7.4 – 7.6 [20,71] p-F-HHSiD Hs Antagonist 7.1 – 7.5 pKi 29,43 ⤷ pKi 7.1 – 7.5 [29,43] dosulepin Hs Antagonist 7.2 pKi 86 ⤷ pKi 7.2 (Ki 6.1x10-8 M) [86] hexahydrosiladifenidol Hs Antagonist 6.5 – 7.7 pKi 7,29 ⤷ pKi 6.5 – 7.7 [7,29] muscarinic toxin 1 Hs Antagonist 7.1 pKi 37 ⤷ pKi 7.1 [37] hexahydrodifenidol Hs Antagonist 7.1 pKi 7 ⤷ pKi 7.1 [7] pirenzepine Rn Antagonist 7.1 pKi 47 ⤷ pKi 7.1 [47] methoctramine Hs Antagonist 6.6 – 7.5 pKi 7,26,29,39 ⤷ pKi 6.6 – 7.5 [7,26,29,39] tropicamide Hs Antagonist 6.9 pKi 11 ⤷ pKi 6.9 [11] solifenacin Hs Antagonist 6.8 pKi 85 ⤷ pKi 6.8 [85] (S)-dimetindene Hs Antagonist 6.5 pKi 10 ⤷ pKi 6.5 (Ki 2.951x10-7 M) [10] Description: Binding to hM4 receptors expressed in CHO cells. otenzepad Rn Antagonist 6.5 pKi 47 ⤷ pKi 6.5 [47] guanylpirenzepine Rn Antagonist 6.2 pKi 101 ⤷ pKi 6.2 [101] muscarinic toxin 2 Hs Antagonist 5.9 pKi 37 ⤷ pKi 5.9 [37] VU0255035 Hs Antagonist 5.9 pKi 84 ⤷ pKi 5.9 [84] lithocholylcholine Hs Antagonist 5.3 pKi 15 ⤷ pKi 5.3 [15] muscarinic toxin 7 Hs Antagonist <5.0 pKi 67 ⤷ pKi <5.0 [67] ML381 Hs Antagonist >4.5 pKi 32 ⤷ pKi >4.5 (Ki <3x10-5 M) [32]
View species-specific antagonist tables
Antagonist Comments
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 [2].

Allosteric Modulators
Key to terms and symbols	View all chemical structures	Click column headers to sort
Ligand Sp. Action Value Parameter Reference LY2033298 Hs Positive 4.9 – 5.5 pKB 14,89 ⤷ pKB 4.9 – 5.5 [14,89] KT 5720 Hs Neutral 6.4 pKd 56 ⤷ pKd 6.4 [56] WIN 51,708 Hs Negative 6.2 pKd 57 ⤷ pKd 6.2 [57] WIN 62,577 Hs Negative 5.9 pKd 57 ⤷ pKd 5.9 [57] Gö 7874 Hs Neutral 5.7 pKd 56 ⤷ pKd 5.7 [56] alcuronium Hs Negative 5.6 pKd 45 ⤷ pKd 5.6 [45] LY2119620 Hs Positive 5.5 pKd 21 ⤷ pKd 5.5 [21] brucine Hs Negative 4.7 – 6.0 pKd 45,55 ⤷ pKd 4.7 – 6.0 [45,55] staurosporine Hs Neutral 5.3 pKd 56 ⤷ pKd 5.3 [56] strychnine Hs Positive 4.8 – 5.0 pKd 45,52 ⤷ pKd 4.8 – 5.0 [45,52] vinburnine Hs Positive 4.6 pKd 45 ⤷ pKd 4.6 [45] N-benzyl brucine Hs Negative 4.5 pKd 55 ⤷ pKd 4.5 [55] N-benzyl brucine Hs Neutral 4.5 pKd 55 ⤷ pKd 4.5 [55] N-chloromethyl-brucine Hs Neutral 4.4 pKd 55 ⤷ pKd 4.4 [55] vincamine Hs Positive 4.2 pKd 45 ⤷ pKd 4.2 [45] thiochrome Hs Positive 4.0 pKd 53 ⤷ pKd 4.0 [53] brucine N-oxide Hs Neutral 3.6 pKd 55 ⤷ pKd 3.6 [55] brucine N-oxide Hs Positive 3.6 pKd 55 ⤷ pKd 3.6 [55] muscarinic toxin 3 Hs Negative 8.7 pKi 46,70 ⤷ pKi 8.7 [46,70] emraclidine Hs Positive 7.9 pEC50 8 ⤷ pEC50 7.9 (EC50 1.22x10-8 M) [8] Description: Determined in human M4 HEK293 cell assay using EC20 of acetylcholine. VU0467154 Rn Positive 7.8 pEC50 6 ⤷ pEC50 7.8 (EC50 1.78x10-8 M) [6] VU0152100 Rn Positive 6.4 pEC50 4 ⤷ pEC50 6.4 (EC50 3.8x10-7 M) [4] VU0152099 Rn Positive 6.4 pEC50 4 ⤷ pEC50 6.4 (EC50 4.03x10-7 M) [4] VU0467154 Hs Positive 6.2 pEC50 6 ⤷ pEC50 6.2 (EC50 6.31x10-7 M) [6] Description: Potentiation of ACh response at human receptor VU0467154 Monkey Positive 6.0 pEC50 6 ⤷ pEC50 6.0 (EC50 1x10-6 M) [6] VU0010010 Hs Positive - - 19 ⤷ [19]
View species-specific allosteric modulator tables

Primary Transduction Mechanisms
Transducer	Effector/Response
Gi/Go family	Adenylyl cyclase inhibition
References:  63,76

Tissue Distribution
Esophageal smooth muscle. Species:  Human Technique:  Radioligand binding. References:  79
Bladder. Species:  Human Technique:  RT-PCR. References:  96
CNS: forebrain. Species:  Mouse Technique:  immunocytochemistry. References:  42
CNS: cerebral cortex, corpus striatum, thalamus, hypothalamus, pons-medulla. Species:  Mouse Technique:  Radioligand binding. References:  68
Heart: intrinsic neurons. Species:  Rat Technique:  in situ hybridisation. References:  38
CNS: basal forebrain, pedunculopontine and laterodorsal tegmental nuclei. Species:  Rat Technique:  in situ hybridisation. References:  99
CNS: cerebral cortex, hippocampus, corpus striatum, olfactory tubercle, midbrain, pons-medulla, cerebellum. Species:  Rat Technique:  Immunoprecipitation. References:  111
CNS: caudate putamen, nucleus accumbens, olfactory tubercle. Species:  Rat Technique:  in situ hybridisation. References:  104
CNS: hippocampus. Species:  Rat Technique:  immunocytochemistry. References:  58
Vestibular system. Species:  Rat Technique:  RT-PCR. References:  100

Expression Datasets
Show »« Hide Log average relative transcript abundance in mouse tissues measured by qPCR from Regard, J.B., Sato, I.T., and Coughlin, S.R. (2008). Anatomical profiling of G protein-coupled receptor expression. Cell, 135(3): 561-71. [PMID:18984166] [Raw data: website] There should be a chart of expression data here, you may need to enable JavaScript!

Functional Assays
Measurement of IP1 levels in murine fibroblast cells (B82) transfected with the rat M4 receptor. Species:  Rat Tissue:  B82 cells. Response measured:  Stimulation of IP1 accumulation. References:  47
Measurement of cAMP levels in murine fibroblast cells (B82) transfected with the rat M4 receptor. Species:  Rat Tissue:  B82 cells. Response measured:  Inhibition of cAMP accumulation. References:  47
Measurement of cAMP levels in JEG-3 cells transfected with the human M2 receptor, using a cAMP response element (CRE)-coupled luciferase construct as the reporter. Species:  Human Tissue:  JEG-3 cells. Response measured:  Inhibition of cAMP accumulation. References:  63
Measurement of cAMP levels in CHO cells transfected with the human M4 receptor. Species:  Human Tissue:  CHO cells. Response measured:  Inhibition of cAMP accumulation. References:  18
Measurement of ERK1/2 activity in COS-7 cells transfected with the human M4 receptor. Species:  Human Tissue:  COS-7 cells. Response measured:  Increase in ERK1/2 activity. References:  81
Measurement of Ca2+ channel activity in rat superior cervical ganglion neurons endogenously expressing the M4 receptor. Species:  Rat Tissue:  Superior cervical ganglion neurons. Response measured:  Inhibition of Ca2+ channels. References:  30-31
Measurement of AC activity in rat striatal homogenates endogenously expressing the M4 receptor. Species:  Rat Tissue:  Corpus striatum. Response measured:  Inhibition of AC activity.