Anti Muscarinic Acetylcholine Receptor M2 (CHRM2) pAb (Rabbit, Antiserum)

Muscarinic acetylcholine receptors, or mAChRs, are acetylcholine receptors that form G protein-coupled receptor complexes in the cell membranes of certain neurons and other cells. They play several roles, including acting as the main end-receptor stimulated by acetylcholine released from postganglionic fibers in the parasympathetic nervous system. Muscarinic receptors are so named because they are more sensitive to muscarine than to nicotine. By the use of selective radioactively labeled agonist and antagonist substances, five subtypes of muscarinic receptors have been determined, named M1-M5 (using an upper case M and subscript number). M1, M3, M5 receptors are coupled with Gq proteins, while M2 and M4 receptors are coupled with Gi/o proteins.

M2 receptor: The M2 muscarinic receptors are located in the heart, where they act to slow the heart rate down to normal sinus rhythm, by slowing the speed of depolarization. In humans under resting conditions vagal activity dominates over sympathetic activity. Hence inhibition of m2 receptors (e.g. by atropine) will cause a raise in heart rate. They also moderately reduce contractile forces of the atrial cardiac muscle, and reduce conduction velocity of the atrioventricular node (AV node). It also serves to slightly decrease the contractile forces of the ventricular muscle.

References:
1) K. Shiozaki, E. Iseki, H. Uchiyama, Y. Watanabe, T. Haga, K. Kameyama, T. Yamada, T. Yamamoto, K. Kosaka Alterations of muscarinic acetylcholine receptor subtypes in diffuse Lewy body disease: relation to Alzheimer's's disease J Neurol Neurosurg Psychiatry. 1999 Aug; 67 (2): 209-13. ​​​​
​​2) Kazumasa Shiozaki, Eizo Iseki, Hiroaki Hino, Kenji Kosaka Distribution of m1 acetylcholine receptors in the hippocampus of patients with patients and patients with dementia with Lewy bodies-an immunohistochemistry study J Neurol Sci. 2001 Dec 15.