ASSEMBLY OF FUNCTIONAL GABA(A) RECEPTORS IN INSECT CELLS USING BACULOVIRUS EXPRESSION VECTORS

WE have constructed recombinant baculoviruses containing cDNAs encoding either the alpha-1 or the beta-1-subunit of the bovine GABA(A) receptor. In Spodoptera frugiperda (IPLB-Sf-21) cells infected with recombinant virus expressing either the alpha-1 or beta-1-subunit, or in cells coinfected with both viruses, functional GABA(A) receptors were detected by whole-cell electrophysiological recordings. The threshold for the responses mediated by the homo-oligomeric channels (alpha- or beta-) was 2-3 X 10(-6) M GABA, and for the co-infected cells was 8 X 10(-8) M GABA, suggesting that hetero-oligomeric channels formed in these cells. All GABA-induced currents were found to be inhibited by bicuculline and picrotoxin, potentiated by pentobarbital but were insensitive to benzodiazepines.