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. Primary transducing effect is Pi turnover. Expressed in head region of the larva. In adults, expression is seen in the periventricularis magnocellularis (PVM) neuron. Expressed throughout development from embryonic to adult stage, highest level seen in early larvae. Isoform A is the most abundant and isoform C is the least. Belongs to the G-protein coupled receptor 1 family. Muscarinic acetylcholine receptor subfamily.