Protein / target

Muscarinic acetylcholine receptor M1

CHRM1P11229Homo sapiensSwiss-Prot
Clinically validated
Therapeutic maturity
40
Approved medicines
30
Clinical trials
Small-molecule tractable
Druggability
Approved Drug

Protein at a glance

Biological role

Phosphatidylinositol-4,5-bisphosphate phospholipase C activity

Primary system

Nervous system

Strongest disease association

Parkinson disease

Clinical evidence · score 0.67

Therapeutic maturity

Clinically validated target

40 approved medicines against this target

Druggability

Small molecule

Open Targets tractability · Approved Drug

Clinical development

40 approved · 11 in clinical development

30 linked trials

Derived from structured UniProt, Open Targets and literature data on this page.

Protein profile

UniProt 2026_02

Canonical identity and biological annotation from UniProt.

Function

The muscarinic acetylcholine receptor mediates various cellular responses, including inhibition of adenylate cyclase, breakdown of phosphoinositides and modulation of potassium channels through the action of G proteins. Primary transducing effect is Pi turnover

Subcellular location

Cell membranePostsynaptic cell membrane
Domains and Gene Ontology detail (30)

Gene Ontology

  • Caxon terminus
  • Ccholinergic synapse
  • Cdendrite
  • Cglutamatergic synapse
  • Cmembrane
  • Cplasma membrane
  • Cpostsynaptic density membrane
  • Cpresynaptic membrane
  • CSchaffer collateral - CA1 synapse
  • Csynapse
  • FG protein-coupled acetylcholine receptor activity
  • Fphosphatidylinositol-4,5-bisphosphate phospholipase C activity

460 aa · 51 kDa · 2 isoforms

Biological roles

Reactome v97

What this protein does, drawn together from its UniProt function, Gene Ontology terms and Reactome pathways.

Synaptic signallingUniProt · GOG protein-coupled signallingGOExcitatory neurotransmissionGOMotor controlGO
View supporting evidence

Synaptic signalling

  • ·Postsynaptic cell membrane
  • ·cholinergic synapse
  • ·glutamatergic synapse
  • ·postsynaptic density membrane

G protein-coupled signalling

  • ·G protein-coupled acetylcholine receptor activity
  • ·adenylate cyclase-inhibiting G protein-coupled acetylcholine receptor signaling pathway
  • ·G protein-coupled acetylcholine receptor signaling pathway
  • ·G protein-coupled receptor signaling pathway

Excitatory neurotransmission

  • ·glutamatergic synapse

Motor control

  • ·regulation of locomotion
View underlying pathways (2)

Concepts derived from UniProt GO Reactome — each badge above shows which sources supported that role.

Interaction neighbourhood

STRING v12.0

Proteins with the strongest functional or physical association. Node size and line weight reflect STRING confidence; hover or select a partner to inspect one association.

GNAQGRM5LPAR6GNA11LPAR1KNG1GNG12CHRM3LPAR3CHRM2CHRM1

10 strongest partners — larger node and heavier line mean higher confidence

Functional and physical associations from STRING v12.0. Only associations with this protein are drawn — partner-to-partner links are not part of this evidence.

Drugs targeting this protein

2

Whether each drug engages this protein directly or through a complex, and how many other targets are recorded for it. Direct binders with few recorded targets are listed first.

Pilocarpine
Narrow target profileApprovedAgonist

Muscarinic acetylcholine receptor M1 agonist

Appears in clinical studies involving xerostomia, Sjogren syndrome, angle-closure glaucoma, Miosis

Direct interaction with this protein · 1 of 2 recorded protein targets — narrow recorded profile

Scopolamine
Narrow target profileApprovedAntagonist

Muscarinic acetylcholine receptor M1 antagonist

Appears in clinical studies involving post operative nausea and vomiting, Nausea, Nausea and vomiting, motion sickness

Direct interaction with this protein · Only this protein recorded as a target

ChEMBL mechanism, action type and target identity. Open Targets clinical status and indications.

Translational evidence

Open Targets 26

Why this target matters therapeutically — disease associations, drugs in development, tractability and safety, from Open Targets.

Highest-confidence therapeutic associations

Diseases where a drug acting on this target has already reached clinical development.

chronic obstructive pulmonary disease0.99

Clinical · overall 0.61

Parkinson disease0.99

Clinical · overall 0.67

gastrointestinal disease0.96

Clinical · overall 0.58

asthma0.95

Clinical · overall 0.58

myopia0.95

Clinical · overall 0.59

Highest overall evidence

Remaining associations by Open Targets' aggregated evidence score.

Peptic ulcer0.58

Clinical

Hyperhidrosis0.56

Clinical

Mydriasis0.55

Clinical

Nausea0.54

Clinical

allergic rhinitis0.54

Clinical

Show all associations
Parkinson disease0.67
chronic obstructive pulmonary disease0.61
myopia0.59
gastrointestinal disease0.58
asthma0.58
Peptic ulcer0.58
Hyperhidrosis0.56
Mydriasis0.55
Nausea0.54
allergic rhinitis0.54

Open Targets ranks 339 associations for this target and we store the top 10 by aggregated score. The long tail is largely literature co-mention and RNA-expression evidence, not evidence that this target drives those diseases.

Known drugs · 53 total

PROCYCLIDINEApproval

Parkinson disease

TRIHEXYPHENIDYL HYDROCHLORIDEEarly Phase 1

schizophrenia

CEVIMELINE HYDROCHLORIDEApproval

xerostomia

METHIXENEApproval

Parkinson disease

BENZTROPINE MESYLATEApproval

Parkinson disease · Back pain

MINAPRINE HYDROCHLORIDEUnknown
MK-7622Phase 2

Alzheimer disease · Alzheimer disease

GLYCOPYRRONIUMApproval

chronic obstructive pulmonary disease · asthma · chronic obstructive pulmonary disease

AFACIFENACINPhase 2

overactive bladder

ASM-024Phase 2

asthma · allergic asthma · chronic obstructive pulmonary disease

Tractability

SM · Approved DrugSM · Structure with LigandSM · High-Quality LigandSM · Druggable FamilyAB · GO CC high confAB · UniProt loc med confAB · UniProt SigP or TMHMMPR · Half-life DataPR · Small Molecule Binder

Safety liabilities

acidosisexhaustiongastrointestinal side effectsincreased gastric acid secretionproconvulsantdecreased gastric acid secretiondecreased gastric acid secretionincreased blood pressurehyperthermiaabdominal crampsincreased/decreased blood pressuredecreased convulsions

Clinical trials

30

Trials of drugs that target this protein — reached indirectly through those drugs, so a trial listed here studies the drug, not the protein.

Show remaining trials (24)

RECRUITING · via Scopolamine · NCT04366518

ENROLLING_BY_INVITATION · via Scopolamine · NCT07423923

COMPLETED · via Scopolamine · NCT02273895

ClinicalTrials.gov via the drug-target graph.

Forefront confidence

Synthesis

Our own weighting of the evidence behind each disease association. Human genetics and clinical evidence count for most; literature co-mention counts for little, because two entities sharing an abstract is not evidence that one drives the other.

Parkinson diseaseWell supported
0.79
agreement 0.660.92
Clinical79%Pathway17%Literature4%

Open Targets aggregate 0.67 · 3 independent evidence families

chronic obstructive pulmonary diseaseModerately supported
0.75
agreement 0.590.90
Clinical99%Literature1%

Open Targets aggregate 0.61 · 2 independent evidence families

myopiaModerately supported
0.72
agreement 0.570.88
Clinical94%Literature6%

Open Targets aggregate 0.59 · 2 independent evidence families

gastrointestinal diseaseModerately supported
0.72
agreement 0.560.89
Clinical100%

Open Targets aggregate 0.58 · 1 independent evidence family

asthmaModerately supported
0.72
agreement 0.570.88
Clinical97%Literature4%

Open Targets aggregate 0.58 · 2 independent evidence families

The evidence agreement range shows how closely the independent evidence families agree — it is not a statistical confidence interval, and nothing here is fitted to outcome data. Derived from Open Targets evidence types under Forefront weighting; the underlying per-type scores are shown above so the calculation can be checked.

What's happening now

7

Recent activity around this target, drawn from one canonical event stream. Every item is reached through 2 drugs that target this protein, so each event is news about that drug rather than about the protein directly.

  1. New publication2024-04-16
    A phosphodiesterase 4 (PDE4) inhibitor, amlexanox, reduces neuroinflammation and neuronal death after pilocarpine-induced seizure.

    Neurotherapeutics : the journal of the American Society for Experimental NeuroTherapeutics · 2024 · 14 citations · Europe PMC · via Pilocarpine

  2. New publication2023-07-20
    Enhanced neuronal activity by suffruticosol A extracted from Paeonia lactiflora via partly BDNF signaling in scopolamine-induced memory-impaired mice.

    Scientific reports · 2023 · 6 citations · Europe PMC · via Scopolamine

  3. New publication2012-01-17
    Phase 2 results from Radiation Therapy Oncology Group Study 0537: a phase 2/3 study comparing acupuncture-like transcutaneous electrical nerve stimulation versus pilocarpine in treating early radiation-induced xerostomia.

    Cancer · 2012 · 34 citations · Europe PMC · via Pilocarpine

  4. New publication2011-05-01
    A phase III randomized, double-blind, placebo-controlled study of pilocarpine for vaginal dryness: North Central Cancer Treatment group study N04CA.

    The journal of supportive oncology · 2011 · 9 citations · Europe PMC · via Pilocarpine

  5. New publication1997-05-01
    Dentate granule cell neurogenesis is increased by seizures and contributes to aberrant network reorganization in the adult rat hippocampus.

    The Journal of neuroscience : the official journal of the Society for Neuroscience · 1997 · 1,402 citations · Europe PMC · via Pilocarpine

  6. New publication1994-12-01
    Estradiol regulates hippocampal dendritic spine density via an N-methyl-D-aspartate receptor-dependent mechanism.

    The Journal of neuroscience : the official journal of the Society for Neuroscience · 1994 · 491 citations · Europe PMC · via Scopolamine

  7. New publication1992-11-01
    Long-term synaptic depression in the striatum: physiological and pharmacological characterization.

    The Journal of neuroscience : the official journal of the Society for Neuroscience · 1992 · 491 citations · Europe PMC · via Scopolamine

Objective event titles are shown unmodified; the event kind and significance line are derived from structured fields. Forefront AttentionEvent stream aggregating Europe PMC Regulatory filings ClinicalTrials.gov.