Structural and pharmacological characterization of the major brain nicotinic acetylcholine receptor subtype stably expressed in mouse fibroblasts.

Previously, we purified the predominant subtype of brain nicotinic acetylcholine receptor (AChR), analyzed its structure, and found that it was composed of two kinds of subunit, with sequences encoded by cDNAs termed alpha 4 and beta 2. Here we express these cDNAs from chicken brain in stably transfected fibroblasts. We demonstrate by synthesis that these cDNAs encode subunit polypeptides of the expected sizes, which coassemble to form receptor macromolecules having the same size as native AChRs. Additionally, we demonstrate that the expressed AChRs exhibit the ligand-binding pharmacology of native brain AChRs and function as acetylcholine-gated ion channels.