M2 muscarinic acetylcholine receptor
E874316
G protein–coupled receptor
integral membrane protein
membrane protein
muscarinic acetylcholine receptor subtype
seven-transmembrane receptor
The M2 muscarinic acetylcholine receptor is a G protein–coupled receptor subtype primarily found in the heart, where it mediates parasympathetic (vagal) effects such as slowing heart rate and reducing contractility.
All labels observed (1)
| Label | Occurrences |
|---|---|
| M2 muscarinic acetylcholine receptor canonical | 2 |
How this entity was disambiguated
This entity first appeared as the object of triple T10610022 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
NED1
Entity disambiguation (via context triple)
gpt-5-mini-2025-08-07
Target entity: M2 muscarinic acetylcholine receptor Context triple: [Gi protein, couplesToReceptor, M2 muscarinic acetylcholine receptor]
-
A.
NMDA receptor
The NMDA receptor is a glutamate-activated ion channel in the brain that plays a key role in synaptic plasticity, learning, and memory, and is implicated in various neurological and psychiatric disorders.
-
B.
CB2 receptor
The CB2 receptor is a cannabinoid receptor primarily expressed in immune and peripheral tissues, where it modulates inflammation and immune responses and serves as a key target of compounds like THC.
-
C.
CB1 receptor
The CB1 receptor is a G protein–coupled cannabinoid receptor in the brain and nervous system that mediates most of the psychoactive effects of cannabis.
-
D.
GABA
GABA (gamma-aminobutyric acid) is the primary inhibitory neurotransmitter in the mammalian central nervous system, crucial for reducing neuronal excitability and regulating muscle tone and anxiety.
-
E.
Neuron
Neuron is a leading peer-reviewed scientific journal that publishes influential research in neuroscience, covering topics from molecular and cellular mechanisms to systems and cognitive neuroscience.
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
NED2
Entity disambiguation (via description)
gpt-5-mini-2025-08-07
Target entity: M2 muscarinic acetylcholine receptor Target entity description: The M2 muscarinic acetylcholine receptor is a G protein–coupled receptor subtype primarily found in the heart, where it mediates parasympathetic (vagal) effects such as slowing heart rate and reducing contractility.
-
A.
NMDA receptor
The NMDA receptor is a glutamate-activated ion channel in the brain that plays a key role in synaptic plasticity, learning, and memory, and is implicated in various neurological and psychiatric disorders.
-
B.
CB2 receptor
The CB2 receptor is a cannabinoid receptor primarily expressed in immune and peripheral tissues, where it modulates inflammation and immune responses and serves as a key target of compounds like THC.
-
C.
CB1 receptor
The CB1 receptor is a G protein–coupled cannabinoid receptor in the brain and nervous system that mediates most of the psychoactive effects of cannabis.
-
D.
GABA
GABA (gamma-aminobutyric acid) is the primary inhibitory neurotransmitter in the mammalian central nervous system, crucial for reducing neuronal excitability and regulating muscle tone and anxiety.
-
E.
Neuron
Neuron is a leading peer-reviewed scientific journal that publishes influential research in neuroscience, covering topics from molecular and cellular mechanisms to systems and cognitive neuroscience.
- F. None of above. chosen
Statements (48)
| Predicate | Object |
|---|---|
| instanceOf |
G protein–coupled receptor
ⓘ
integral membrane protein ⓘ membrane protein ⓘ muscarinic acetylcholine receptor subtype ⓘ seven-transmembrane receptor ⓘ |
| activatedBy |
parasympathetic nervous system
ⓘ
linked to:
Parasympathetic nervous system
vagal stimulation ⓘ |
| agonist |
carbachol
ⓘ
oxotremorine ⓘ |
| antagonist |
AF-DX 116
ⓘ
atropine ⓘ gallamine ⓘ methoctramine ⓘ scopolamine ⓘ |
| belongsToFamily |
class A GPCR
ⓘ
muscarinic receptor family ⓘ |
| cellularComponent | plasma membrane ⓘ |
| clinicalRelevance |
involved in vagally mediated bradycardia
ⓘ
target in treatment of cardiac arrhythmias ⓘ |
| contrastsWith |
M1 muscarinic acetylcholine receptor
ⓘ
M3 muscarinic acetylcholine receptor ⓘ |
| couplesTo |
Gi protein
ⓘ
Go protein ⓘ |
| downstreamEffect |
hyperpolarizes cardiac pacemaker cells
ⓘ
opens G protein–gated inwardly rectifying K+ channels ⓘ |
| effectOnSecondMessenger | decreases cAMP levels ⓘ |
| encodedBy | CHRM2 gene ⓘ |
| foundIn |
central nervous system
ⓘ
presynaptic nerve terminals ⓘ smooth muscle ⓘ |
| hasTransmembraneDomains | 7 ⓘ |
| ligand |
acetylcholine
ⓘ
muscarine ⓘ |
| organism | human ⓘ |
| pharmacologicalProfile | prefers Gi/Go coupling over Gq/11 ⓘ |
| physiologicalRole |
inhibits neurotransmitter release at some synapses
ⓘ
mediates parasympathetic effects in the heart ⓘ reduces cardiac contractility ⓘ slows atrioventricular conduction ⓘ slows heart rate ⓘ |
| primaryLocation |
atria
ⓘ
atrioventricular node ⓘ cardiac conduction system ⓘ heart ⓘ sinoatrial node ⓘ
linked to:
Sinoatrial node
|
| receptorSubtype | M2 ⓘ |
| signalPathway | inhibition of adenylyl cyclase ⓘ |
| speciesContext | Homo sapiens ⓘ |
How these facts were elicited
The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.
Instruction
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10. # Requirements - If you don't know the subject at all, return an empty list. - If the subject is not a named entity, return an empty list. - Include at least one triple where predicate is "instanceOf". - Do not get too wordy. - Separate several objects into multiple triples with one object.
Input
Subject: M2 muscarinic acetylcholine receptor Description of subject: The M2 muscarinic acetylcholine receptor is a G protein–coupled receptor subtype primarily found in the heart, where it mediates parasympathetic (vagal) effects such as slowing heart rate and reducing contractility.
Referenced by (2)
Full triples — surface form annotated when it differs from this entity's canonical label.