M2 Muscarinic receptor KO (Chrm2 tm1Jwe) Mouse

M2 Muscarinic Receptor Knockout: role in learning and memory, and mediating analgesic effects of muscarinic agonists

The five Muscarinic Acetylcholine (ACh) receptors are G-protein coupled receptors (M1R-M5R). M1R, M3R and M5R selectively couple to Gq/G11; M2R and M4R selectively couple to Gi/Go. M2R knockout mice are viable and fertile, and have no major morphological abnormalities.

M2 muscarinic receptors are located in the central nervous system and the periphery. Studies with M2R knockout mice strongly suggest that the M2 receptor is the key presynaptic muscarinic receptor mediating the inhibition of hippocampal and cortical ACh release. Studies with M2R knockout mice suggest that central M2Rs play important roles in learning and memory. The M2R mediates ACh-mediated reductions in heart rate. Analysis of M2R knockout mice also has shown that the analgesic effects observed after administration of muscarinic agonists are mediated primarily by M2Rs.