Muscarinic acetylcholine receptor M1, Muscarinic acetylcholine receptor M2, Muscarinic acetylcholine receptor M3, Muscarinic acetylcholine receptor M4 (M1 receptor, M2 receptor, M3 receptor, M4 receptor)

Muscarinic acetylcholine receptors M1, M2, M3, and M4 are subtypes of G protein-coupled receptors activated by the neurotransmitter acetylcholine. M1, M3, and M5 primarily couple to Gq/11 proteins, generally mediating excitatory cellular responses, while M2 and M4 couple to Gi/o proteins and mediate inhibitory responses. These receptors regulate a wide range of physiological processes, including cognition (M1, M4), heart rate (M2), smooth muscle contraction (M3), and glandular secretion, and are implicated in multiple diseases such as Alzheimer’s disease, bradyarrhythmia, schizophrenia, COPD, and overactive bladder. They are major therapeutic targets for antimuscarinic and muscarinic agonist drugs used in neurology, cardiology, pulmonology, and urology

Other names

mAChR M1mAChR M2mAChR M3mAChR M4Cholinergic receptor muscarinic M1/M2/M3/M4M1/M2/M3/M4 receptor

Antagonism (e.g., competitive inhibition at muscarinic receptors), Agonism (e.g., direct activation of muscarinic receptor subtypes), Allosteric modulation, Inverse agonism, Inhibition of G protein-coupled signaling pathways