AQ-RA 741, M2 antagonist

Supplementary information

This supplementary information is collated from multiple sources and compiled automatically.

Muscarinic acetylcholine receptors (mAChRs) particularly Muscarinic Acetylcholine Receptor 1 (CHRM1) Muscarinic Acetylcholine Receptor 2 (CM2) Muscarinic Acetylcholine Receptor M3 (CHRM3) and Muscarinic Acetylcholine Receptor M4 (CHRM4) are G protein-coupled receptors (GPCRs). These receptors are involved in acetylcholine binding and signal transduction in the central and peripheral nervous systems. Each subtype has a distinct expression pattern: CHRM1 is mainly found in the cerebral cortex CM2 in the heart CHRM3 in glandular tissues and CHRM4 is present in the striatum and midbrain neurons. The molecular weight of these receptors varies from approximately 50–70 kDa.

Biological function summary

These receptors play pivotal roles in mediating parasympathetic nervous system effects. When acetylcholine binds to these receptors it triggers various intracellular events depending on the receptor subtype and tissue location. CHRM1 is involved in cognitive processes in the brain CM2 regulates cardiac function CHRM3 facilitates glandular secretions and CHRM4 is linked to neuromodulation. They are not traditionally part of a protein complex but interact with various G proteins to carry out their functions.

Pathways

Muscarinic acetylcholine receptors are integral to the cholinergic signaling pathway. This pathway influences both neurotransmitter release and neuronal excitability. In the central nervous system CHRM1 and CHRM4 positively modulate cognitive function working alongside other neurotransmitter systems like dopaminergic and adrenergic pathways. CM2 primarily participates in the cardiac pathway regulating heart rate and contractility through interactions with phospholipase C and adenylate cyclase signaling cascades.

Muscarinic acetylcholine receptors have links to various conditions. CHRM1 and CHRM4 directly relate to Alzheimer's disease affecting cognitive decline through disrupted cholinergic signaling. In cardiac-related disorders CM2 plays a role as malfunction can lead to bradycardia or arrhythmias. These receptors are also connected to other proteins like beta-adrenergic receptors in the heart and dopaminergic receptors in the brain demonstrating their multifaceted roles in physiological and pathological states.