After binding acetylcholine, the AChR responds by an extensive change in conformation that affects all subunits and leads to opening of an ion-conducting channel across the plasma membrane. Neuronal AChR seems to be composed of two different types of subunits: alpha and non-alpha (beta). Alpha-2 subunit can be combined to beta-2 or beta-4 to give rise to functional receptors. The alpha-2:beta-2 nAChR complex is proposed to be a heteropentamer with two subtypes: LS (low agonist sensitivity) with a (alpha-2)3:(beta-2)2 and HS (high agonist sensitivity) with a (alpha-2)2:(beta-2)3 stoichiometry; the subtypes differ in their subunit binding interfaces which are involved in ligand binding. Belongs to the ligand-gated ion channel (TC 1.A.9) family. Acetylcholine receptor (TC 1.A.9.1) subfamily. Alpha-2/CHRNA2 sub-subfamily.