STABLE EXPRESSION OF CLONED RAT GABA(A) RECEPTOR SUBUNITS IN A HUMAN KIDNEY-CELL LINE

A predominant form of the GABA(A)/benzodiazepine receptor-Cl- channel complex is believed to consist of three different 48-55 kDa subunits ( alpha, beta, gamma) with unknown stoichiometry. Plasmids containing th e rat GABA(A) receptor cDNAs coding for alpha1,beta2, and gamma2 were co-transfected, along with a plasmid encoding G418 resistance, into hu man embryonic kidney cells previously transformed with Adenovirus 5 (H EK-293) [J. Gen. Virol., 36 (1977) 59-72]. Four percent of the G418 re sistant colonies were found to express mRNA for all three of the GABA( A) subunits constitutively. A single cell clone derived from one of th e alpha1beta2gamma2 expressors has demonstrated stable electrophysiolo gical characteristics over 25 passages. The GABA-activated Cl- current in this cell line is blocked by picrotoxin and bicuculline, and is mo dulated by a variety of agonist and inverse agonist ligands including diazepam, Ro 154513, zolpidem, and beta-CCE. The cell line has been us ed successfully over a 12-month period as a screen for novel drugs mod ulating GABA-mediated polarization of neuronal cells.