Muscarinic acetylcholine receptor M3 (M3R) and beta-2 adrenergic receptor (β2AR) interaction (M3R-β2AR interaction)

The functional interaction between the Muscarinic acetylcholine receptor M3 (M3R) and the Beta-2 adrenergic receptor (β2AR) is a fundamental regulatory mechanism in the control of airway smooth muscle tone. M3Rs are primarily Gq-coupled and mediate bronchoconstriction and mucus secretion in response to parasympathetic acetylcholine release, while β2ARs are Gs-coupled and promote bronchodilation through the production of cyclic AMP (cAMP) (Meurs, H., et al. (2012). Current Opinion in Pharmacology). These two pathways exhibit significant bidirectional crosstalk; for instance, M3R activation can dampen β2AR-mediated relaxation through protein kinase C (PKC)-mediated phosphorylation of the β2AR or by modulating intracellular calcium sensitivity (Cazzola, M., et al. (2015). European Respiratory Journal). Conversely, β2AR signaling can influence muscarinic pathways, and emerging evidence suggests these receptors may form physical heterodimers that alter their individual pharmacological profiles and desensitization patterns (UniProt: P20309, P07550). This interaction is the primary therapeutic target for combination therapies in respiratory diseases like chronic obstructive pulmonary disease (COPD) and asthma. By utilizing long-acting muscarinic antagonists (LAMAs) alongside long-acting beta-agonists (LABAs), clinicians can achieve superior bronchodilation compared to monotherapy, as the drugs work synergistically to inhibit constrictor stimuli while actively promoting relaxation pathways.

Other names

M3R-ADRB2 crosstalkMuscarinic M3 and Beta-2 Adrenergic receptor complexLAMA/LABA dual targetCholinergic-adrenergic receptor interaction

Simultaneous antagonism of the M3 muscarinic receptor to block cholinergic bronchoconstriction and agonism of the beta-2 adrenergic receptor to promote cAMP-mediated bronchodilation, resulting in synergistic airway relaxation.