Enables G protein-coupled acetylcholine receptor activity. Acts upstream of or within adenylate cyclase-inhibiting G protein-coupled acetylcholine receptor signaling pathway. Located in membrane. Is expressed in several structures, including alimentary system; eye; limb; nervous system; and reproductive system. Orthologous to human CHRM4 (cholinergic receptor muscarinic 4). [provided by Alliance of Genome Resources, Apr 2022]