Enables G protein-coupled acetylcholine receptor activity. Involved in G protein-coupled acetylcholine receptor signaling pathway and regulation of smooth muscle contraction. Located in several cellular components, including asymmetric synapse; neuronal cell body; and symmetric synapse. Is active in glutamatergic synapse. Is integral component of postsynaptic membrane and integral component of presynaptic membrane. Biomarker of mental depression. Human ortholog(s) of this gene implicated in several diseases, including Chagas disease; bipolar disorder; heroin dependence; major depressive disorder; and schizophrenia. Orthologous to human CHRM2 (cholinergic receptor muscarinic 2). [provided by Alliance of Genome Resources, Apr 2022]