Muscarinic acetylcholine receptor M1, M2, M3, M4, and M5 (CHRM1, CHRM2, CHRM3, CHRM4, CHRM5)

Muscarinic acetylcholine receptors M1, M2, M3, M4, and M5 are a family of G protein-coupled receptors (GPCRs) that are activated by the neurotransmitter acetylcholine. They mediate parasympathetic neural effects throughout the central and peripheral nervous systems and are involved in a variety of physiological processes including neuromodulation, smooth muscle contraction, and exocrine gland secretion[3][5][7]. Diverse muscarinic receptor subtypes are distributed differentially across neural and non-neural tissues. Antipsychotic drugs such as olanzapine interact with these receptors, exhibiting antagonistic activity that may contribute both to therapeutic effects (particularly in neuropsychiatric disorders) and to adverse effects, such as anticholinergic side effects and metabolic disturbances[1][3][4][5]. Selective targeting of certain muscarinic subtypes is an area of therapeutic interest for conditions such as schizophrenia and Alzheimer’s disease[5][7].

Other names

Muscarinic receptorsmAChRCHRM1CHRM2CHRM3CHRM4CHRM5

Antagonism of muscarinic acetylcholine receptors blocks acetylcholine-mediated signal transduction, affecting parasympathetic activity and CNS processes[1][3][4][5]. Some drugs (like cevimeline) are agonists, stimulating muscarinic receptors.