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	3,35
Mouse	7	479	2 50.63 cM	Chrm4	cholinergic receptor, muscarinic 4	59
Rat	7	478	3q24	Chrm4	cholinergic receptor, muscarinic 4	46,94,108

Previous and Unofficial Names

HM3 [75-76] | 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:  92

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 82 ⤷ pKd 10.1 (Kd 8x10-11 M) [82] [3H]acetylcholine Hs Agonist 8.2 pKd 52 ⤷ pKd 8.2 (Kd 6.3x10-9 M) [52] pentylthio-TZTP Hs Full agonist 8.7 pKi 44 ⤷ pKi 8.7 [44] NNC 11-1585 Hs Full agonist 8.6 pKi 17 ⤷ pKi 8.6 [17] NNC 11-1607 Hs Full agonist 8.1 pKi 17 ⤷ pKi 8.1 [17] xanomeline Hs Partial agonist 7.4 – 7.7 pKi 61,77,102,109 ⤷ pKi 7.4 – 7.7 [61,77,102,109] NNC 11-1314 Hs Full agonist 7.3 pKi 17 ⤷ pKi 7.3 [17] sabcomeline Hs Partial agonist 7.2 pKi 109 ⤷ pKi 7.2 [109] McN-A-343 Hs Partial agonist 5.6 – 6.7 pKi 49 ⤷ pKi 5.6 – 6.7 [49] cevimeline Hs Agonist 6.0 pKi 58 ⤷ pKi 6.0 (Ki 1.012x10-6 M) [58] Description: Displacement of [3H]QNB from cloned receptor. arecaidine propargyl ester Hs Full agonist 5.9 pKi 44 ⤷ pKi 5.9 [44] methacholine Rn Agonist 5.8 pKi 74,79 ⤷ pKi 5.8 (Ki 1.6x10-6 M) [74,79] arecoline Hs Full agonist 5.5 pKi 44,73,79 ⤷ pKi 5.5 [44,73,79] milameline Hs Partial agonist 5.5 pKi 109 ⤷ pKi 5.5 [109] oxotremorine Hs Full agonist 5.2 pKi 44,79 ⤷ pKi 5.2 [44,79] oxotremorine-M Hs Full agonist 5.2 pKi 44 ⤷ pKi 5.2 [44] pilocarpine Hs Partial agonist 5.2 pKi 44,79 ⤷ pKi 5.2 [44,79] acetylcholine Hs Full agonist 4.5 – 5.6 pKi 44,47 ⤷ pKi 4.5 – 5.6 [44,47] methylfurmethide Hs Full agonist 4.7 pKi 44 ⤷ pKi 4.7 [44] carbachol Hs Full agonist 4.3 – 4.9 pKi 44,109 ⤷ pKi 4.3 – 4.9 [44,109] furtrethonium Hs Full agonist 4.3 pKi 44 ⤷ pKi 4.3 [44] bethanechol Hs Full agonist 4.0 pKi 44,79 ⤷ pKi 4.0 [44,79] (+)-aceclidine Hs Full agonist 5.4 pEC50 27 ⤷ pEC50 5.4 [27] (-)-aceclidine Hs Partial agonist 4.8 pEC50 27 ⤷ pEC50 4.8 [27] iperoxo Hs Agonist - - 82 ⤷ [82]
View species-specific agonist tables
Agonist Comments
The binding data for McN-A-343 [49] is found on rat striatum. Please consult references [5,53,79,101] 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 [53] and full agonists [79,101] 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 43,75 ⤷ pKd 9.7 – 10.5 (Kd 2x10-10 – 3.16x10-11 M) [43,75] [3H]N-methyl scopolamine Hs Antagonist 9.9 – 10.2 pKd 11,43-44,48,51,101 ⤷ pKd 9.9 – 10.2 (Kd 1.4x10-10 – 6x10-11 M) [11,43-44,48,51,101] [3H]AF DX-384 Hs Antagonist 8.7 pKd 12,64,97 ⤷ pKd 8.7 [12,64,97] biperiden Hs Antagonist 8.6 pKd 2 ⤷ pKd 8.6 (Kd 2.4x10-9 M) [2] otenzepad Hs Antagonist 7.0 pKd 28 ⤷ pKd 7.0 [28] tiotropium Hs Antagonist 10.2 – 10.6 pKi 89,91 ⤷ pKi 10.2 – 10.6 [89,91] 3-quinuclidinyl-benzilate Hs Antagonist 10.4 pKi 10 ⤷ pKi 10.4 (Ki 4x10-11 M) [10] umeclidinium Hs Antagonist 10.3 pKi 81 ⤷ pKi 10.3 [81] propantheline Hs Antagonist 10.2 pKi 42 ⤷ pKi 10.2 [42] aclidinium Hs Antagonist 10.0 pKi 91 ⤷ pKi 10.0 [91] oxyphenonium Hs Antagonist 9.8 pKi 10 ⤷ pKi 9.8 (Ki 1.45x10-10 M) [10] atropine Rn Antagonist 9.7 pKi 46 ⤷ pKi 9.7 [46] glycopyrrolate Hs Antagonist 9.1 – 10.0 pKi 87,89 ⤷ pKi 9.1 – 10.0 [87,89] AE9C90CB Hs Antagonist 9.5 pKi 84 ⤷ pKi 9.5 [84] mepenzolic acid Hs Antagonist 9.4 pKi 10 ⤷ pKi 9.4 (Ki 3.6x10-10 M) [10] scopolamine Hs Antagonist 9.1 – 9.5 pKi 2,42 ⤷ pKi 9.1 – 9.5 [2,42] revefenacin Hs Antagonist 9.3 pKi 39 ⤷ pKi 9.3 (Ki 5.5x10-10 M) [39] 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 40 ⤷ pKi 9.2 [40] 4-DAMP Rn Antagonist 9.1 pKi 46 ⤷ pKi 9.1 [46] atropine Hs Antagonist 8.7 – 9.5 pKi 19,40,42,76 ⤷ pKi 8.7 – 9.5 [19,40,42,76] 4-DAMP Hs Antagonist 8.9 pKi 25 ⤷ pKi 8.9 [25] oxybutynin Hs Antagonist 8.4 – 8.7 pKi 24,84 ⤷ pKi 8.4 – 8.7 [24,84] muscarinic toxin 3 Hs Antagonist 8.5 pKi 10 ⤷ pKi 8.5 (Ki 3x10-9 M) [10] silahexocyclium Hs Antagonist 8.5 pKi 7 ⤷ pKi 8.5 [7] tolterodine Hs Antagonist 8.3 – 8.4 pKi 32,84 ⤷ pKi 8.3 – 8.4 [32,84] UH-AH 37 Hs Antagonist 8.3 – 8.4 pKi 32,107 ⤷ pKi 8.3 – 8.4 [32,107] hexocyclium Hs Antagonist 8.3 pKi 7 ⤷ pKi 8.3 [7] dicyclomine Hs Antagonist 8.3 pKi 10 ⤷ pKi 8.3 (Ki 5x10-9 M) [10] PCS1055 Hs Antagonist 8.2 pKi 19 ⤷ pKi 8.2 [19] himbacine Hs Antagonist 7.9 – 8.4 pKi 10,25,45,63 ⤷ pKi 8.4 (Ki 4x10-9 M) [10] pKi 7.9 – 8.2 [25,45,63] amitriptyline Hs Antagonist 8.1 pKi 85 ⤷ pKi 8.1 (Ki 7.2x10-9 M) [85] AQ-RA 741 Hs Antagonist 7.8 – 8.2 pKi 25,32 ⤷ pKi 7.8 – 8.2 [25,32] tripitramine Hs Antagonist 7.9 pKi 65 ⤷ pKi 7.9 [65] darifenacin Hs Antagonist 7.3 – 8.1 pKi 32,40,84 ⤷ pKi 7.3 – 8.1 [32,40,84] hexahydrosiladifenidol Rn Antagonist 7.7 pKi 46 ⤷ pKi 7.7 [46] AFDX384 Hs Antagonist 7.3 – 8.0 pKi 19,25 ⤷ pKi 7.3 – 8.0 [19,25] pirenzepine Hs Antagonist 7.0 – 8.1 pKi 10,25,38,42,45,107 ⤷ pKi 8.1 (Ki 8x10-9 M) [10] pKi 7.0 – 7.6 [25,38,42,45,107] PD 102807 Hs Antagonist 7.4 – 7.6 pKi 19,70 ⤷ pKi 7.4 – 7.6 [19,70] p-F-HHSiD Hs Antagonist 7.1 – 7.5 pKi 28,42 ⤷ pKi 7.1 – 7.5 [28,42] dosulepin Hs Antagonist 7.2 pKi 85 ⤷ pKi 7.2 (Ki 6.1x10-8 M) [85] hexahydrosiladifenidol Hs Antagonist 6.5 – 7.7 pKi 7,28 ⤷ pKi 6.5 – 7.7 [7,28] muscarinic toxin 1 Hs Antagonist 7.1 pKi 36 ⤷ pKi 7.1 [36] hexahydrodifenidol Hs Antagonist 7.1 pKi 7 ⤷ pKi 7.1 [7] pirenzepine Rn Antagonist 7.1 pKi 46 ⤷ pKi 7.1 [46] methoctramine Hs Antagonist 6.6 – 7.5 pKi 7,25,28,38 ⤷ pKi 6.6 – 7.5 [7,25,28,38] tropicamide Hs Antagonist 6.9 pKi 10 ⤷ pKi 6.9 [10] solifenacin Hs Antagonist 6.8 pKi 84 ⤷ pKi 6.8 [84] (S)-dimetindene Hs Antagonist 6.5 pKi 9 ⤷ pKi 6.5 (Ki 2.951x10-7 M) [9] Description: Binding to hM4 receptors expressed in CHO cells. otenzepad Rn Antagonist 6.5 pKi 46 ⤷ pKi 6.5 [46] guanylpirenzepine Rn Antagonist 6.2 pKi 100 ⤷ pKi 6.2 [100] muscarinic toxin 2 Hs Antagonist 5.9 pKi 36 ⤷ pKi 5.9 [36] VU0255035 Hs Antagonist 5.9 pKi 83 ⤷ pKi 5.9 [83] lithocholylcholine Hs Antagonist 5.3 pKi 14 ⤷ pKi 5.3 [14] muscarinic toxin 7 Hs Antagonist <5.0 pKi 66 ⤷ pKi <5.0 [66] ML381 Hs Antagonist >4.5 pKi 31 ⤷ pKi >4.5 (Ki <3x10-5 M) [31]
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 13,88 ⤷ pKB 4.9 – 5.5 [13,88] KT 5720 Hs Neutral 6.4 pKd 55 ⤷ pKd 6.4 [55] WIN 51,708 Hs Negative 6.2 pKd 56 ⤷ pKd 6.2 [56] WIN 62,577 Hs Negative 5.9 pKd 56 ⤷ pKd 5.9 [56] Gö 7874 Hs Neutral 5.7 pKd 55 ⤷ pKd 5.7 [55] alcuronium Hs Negative 5.6 pKd 44 ⤷ pKd 5.6 [44] LY2119620 Hs Positive 5.5 pKd 20 ⤷ pKd 5.5 [20] brucine Hs Negative 4.7 – 6.0 pKd 44,54 ⤷ pKd 4.7 – 6.0 [44,54] staurosporine Hs Neutral 5.3 pKd 55 ⤷ pKd 5.3 [55] strychnine Hs Positive 4.8 – 5.0 pKd 44,51 ⤷ pKd 4.8 – 5.0 [44,51] vinburnine Hs Positive 4.6 pKd 44 ⤷ pKd 4.6 [44] N-benzyl brucine Hs Negative 4.5 pKd 54 ⤷ pKd 4.5 [54] N-benzyl brucine Hs Neutral 4.5 pKd 54 ⤷ pKd 4.5 [54] N-chloromethyl-brucine Hs Neutral 4.4 pKd 54 ⤷ pKd 4.4 [54] vincamine Hs Positive 4.2 pKd 44 ⤷ pKd 4.2 [44] thiochrome Hs Positive 4.0 pKd 52 ⤷ pKd 4.0 [52] brucine N-oxide Hs Neutral 3.6 pKd 54 ⤷ pKd 3.6 [54] brucine N-oxide Hs Positive 3.6 pKd 54 ⤷ pKd 3.6 [54] muscarinic toxin 3 Hs Negative 8.7 pKi 45,69 ⤷ pKi 8.7 [45,69] 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 - - 18 ⤷ [18]
View species-specific allosteric modulator tables

Primary Transduction Mechanisms
Transducer	Effector/Response
Gi/Go family	Adenylyl cyclase inhibition
References:  62,75

Tissue Distribution
Esophageal smooth muscle. Species:  Human Technique:  Radioligand binding. References:  78
Bladder. Species:  Human Technique:  RT-PCR. References:  95
CNS: forebrain. Species:  Mouse Technique:  immunocytochemistry. References:  41
CNS: cerebral cortex, corpus striatum, thalamus, hypothalamus, pons-medulla. Species:  Mouse Technique:  Radioligand binding. References:  67
Heart: intrinsic neurons. Species:  Rat Technique:  in situ hybridisation. References:  37
CNS: basal forebrain, pedunculopontine and laterodorsal tegmental nuclei. Species:  Rat Technique:  in situ hybridisation. References:  98
CNS: cerebral cortex, hippocampus, corpus striatum, olfactory tubercle, midbrain, pons-medulla, cerebellum. Species:  Rat Technique:  Immunoprecipitation. References:  110
CNS: caudate putamen, nucleus accumbens, olfactory tubercle. Species:  Rat Technique:  in situ hybridisation. References:  103
CNS: hippocampus. Species:  Rat Technique:  immunocytochemistry. References:  57
Vestibular system. Species:  Rat Technique:  RT-PCR. References:  99

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:  46
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:  46
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:  62
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:  17
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:  80
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:  29-30
Measurement of AC activity in rat striatal homogenates endogenously expressing the M4 receptor. Species:  Rat Tissue:  Corpus striatum. Response measured:  Inhibition of AC activity. References:  26,68
Measurement of the effects of a ligand on the level, or rate, of binding of GTPγ35S to membranes. Species:  Human Tissue:  CHO cells. Response measured:  The binding of GTPγ35S to G proteins coupled to the receptor. References:  1,50-53,55-56
Measurement of the effects of a ligand on the rate of hydrolysis of GTP by G proteins in membranes. Species:  Human Tissue:  CHO cell membranes. Response measured:  Generation of 32Pi from [γ-32P]GTP. References:  1,53

Physiological Functions