The muscarinic acetylcholine receptor mediates various cellular responses, including inhibition of adenylate cyclase, breakdown of phosphoinositides and modulation of potassium channels through the action of G proteins (PubMed:10635059, PubMed:12927813). Primary transducing effect is Pi turnover (By similarity). Enhances the release of the neurotransmitter acetlycholine in cholinergic motor neurons, which in turn positively feeds back to depolarize body wall muscles and allows for the maintenance of normal body posture and locomotion (PubMed:18614679). Isoform a and isoform b are expressed at all developmental stages examined, isoform a is more abundant at embryonic and early larval stages and isoform b at first larval instar. Belongs to the G-protein coupled receptor 1 family. Muscarinic acetylcholine receptor subfamily.