Abstract: Nucleic acids encoding each of three subunits, .alpha.1B, .alpha.2.delta., and .beta.3, of a calcium channel, are disclosed. Also disclosed are vectors containing the nucleic acids encoding the subunits; host cells containing the nucleic acids encoding the subunits; methods of isolating nucleic acids encoding related calcium channel subunits; the subunit proteins; fusion proteins comprising the subunit proteins; antibodies to the subunit proteins; assays to identify agents that modulate calcium channel activity, and agents identified thereby; methods of treating certain central nervous system disorders by altering calcium channel activity; and methods of diagnosing diseases associated with particular calcium channels, such as Lambert-Eaton syndrome.