Muscarinic acetylcholine receptor M2 and M3 (CHRM2/CHRM3)

The muscarinic acetylcholine receptors M2 (CHRM2) and M3 (CHRM3) are G protein-coupled receptors that play central roles in the parasympathetic nervous system's response to acetylcholine [1, 2]. CHRM2 is primarily coupled to Gi proteins and is highly expressed in the heart and central nervous system, where it acts to decrease heart rate and modulate neurotransmitter release [2, 11]. CHRM3 is coupled to Gq proteins and is found in smooth muscles and exocrine glands, where it mediates contraction of the bladder and airways and stimulates glandular secretions [2, 15]. These receptors are critical therapeutic targets; for instance, antagonists are used to treat overactive bladder by relaxing the detrusor muscle and to manage COPD and asthma by inducing bronchodilation [8, 15]. However, the lack of subtype selectivity in many current drugs leads to common side effects such as dry mouth, constipation, and tachycardia [2, 5]. Beyond autonomic functions, CHRM2 and CHRM3 are also implicated in cognitive processes, and their dysregulation is associated with Alzheimer's disease and certain cancers [6, 12, 17].

Other names

M2 receptorM3 receptorCholinergic receptor muscarinic 2Cholinergic receptor muscarinic 3M2RM3RMuscarinic acetylcholine receptor 2Muscarinic acetylcholine receptor 3

Muscarinic receptor antagonist