Alpha subunit of nicotinic acetylcholine receptor (nAChR) (PubMed:9221782, PubMed:15990870, PubMed:20027209). Probably acts in cholinergic motoneurons to regulate presynaptic neurotransmitter release, thereby ensuring normal level of excitation of cholinergic motoneurons during locomotion (PubMed:20027209). Involved in nAChR sensitivity to nicotine (PubMed:9221782, PubMed:15990870). Component of nicotinic acetylcholine receptor (PubMed:15990870, PubMed:20027209). In muscles, composed of 2 non-alpha subunits lev-1 and unc-29, and 3 alpha subunits unc-38, unc-63 and lev-8 (PubMed:15990870). In cholinergic motoneurons, composed of 2 non-alpha subunits acr-2 and acr-3, and 3 alpha subunits unc-38, unc-63 and acr-12 (PubMed:20027209). Co-localizes with unc-29 and lev-1 and partially with acr-12 and acr-8 at nerve cord synapses. RNAi-mediated knockdown causes a resistance to nicotine-mediated paralysis. Belongs to the ligand-gated ion channel (TC 1.A.9) family. Acetylcholine receptor (TC 1.A.9.1) subfamily.