Cholinergic Receptor, Muscarinic 2 (CHRM2)

The is a muscarinic acetylcholine receptor.M2 muscarinic receptors act via a G_i type receptor, which causes a decrease in cAMP in the cell, generally leading to inhibitory-type effects.In addition, they modulate muscarinic potassium channels. In the heart, this contributes to a decreased heart rate.

The M2 muscarinic receptors are located in the heart, where they act to slow the heart rate down to normal sinus rhythm after stimulatory actions of the sympathetic nervous system, by slowing the speed of depolarization. They also reduce contractile forces of the atrial cardiac muscle, and reduce conduction velocity of the atrioventricular node (AV node). However, they have no effect on the contractile forces of the ventricular muscle.