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:11032868, PubMed:11700045). Primary transducing effect is Pi turnover (By similarity). Regulates the activity of ventral cord motor neurons (PubMed:18614679). Couples to the G(o)-alpha G-protein subunit goa-1 to negatively regulate cholinergic receptor activity in the presence of high levels of the neurotransmitter acetylcholine in ventral cord motor neurons (PubMed:18614679). As acetylcholine depolarizes body wall muscles, modulation of acetylcholine levels most likely results in the control locomotory behavior and egg-laying (PubMed:12954868, PubMed:18614679). Diffusely localized in axons. Expressed in putative sensory neurons, many cells of the ventral cord and in the HSN motor neurons (PubMed:11032868). Expressed in some cholinergic motor neurons and GABAergic motor neurons, which are the two major types of ventral cord motor neurons (PubMed:18614679). Expressed throughout development from the embryo to the adult (PubMed:11032868, PubMed:11700045). Expressed in the head region of larva (PubMed:11032868). Egg-laying defect whereby 30% of eggs are laid at an early developmental stage (PubMed:12954868). Increased sensitivity to the acetylcholine esterase inhibitor Aldicarb, which results in accelerated paralysis likely due to enhanced acetylcholine release by ventral cord neurons and enhanced depolarization of muscles on one side of the body (PubMed:18614679). Exploratory behavior is similar to wild-type, but in contrast to wild-type, there is irregular locomotory behavior characterized by a 9.2% increase in speed of locomotion over a 1-minute interval, decreased turning frequency, reduced rate of reversals, and a 25% increase in the maximal distance covered over a 40 second interval (PubMed:18614679). Double knockout with the G-protein coupled receptor for GABA subunit gbb-2 results in a slight increase in sensitivity to Aldicarb and accelerated paralysis 50 minutes following exposure to Aldicarb as compared to the gar-2 and gbb-2 single mutants (PubMed:18614679). Belongs to the G-protein coupled receptor 1 family. Muscarinic acetylcholine receptor subfamily.