The goals of the present work were to characterize the binding profile of n
ine benzodiazepine ligands in Spodotera frugiperda (Sf-9) insect cells expr
essing specific gamma aminobutyric acid (A) (GABA(A)) receptor subunit comb
inations and compare the affinities to those for the receptors in the rat c
erebellum. Three recombinant baculovirus constructs, each harboring a diffe
rent GABA(A) receptor subunit, were introduced into insect cells by simulta
neous infection. Saturation and competition binding assays were carried out
in membranes from Sf-9 cells infected with either alpha (1)beta (2)gamma (
2) or alpha (6)beta (2)y(2) subunit combinations. The affinities of the lig
ands to the alpha (1)beta (2)gamma (2) or alpha (6)beta (2)gamma (2) recept
ors expressed in Sf-9 cells were similar to the affinities previously deter
mined for the alpha(1) or alpha(6) subunit-containing GABA(A) receptors in
the rat cerebellum, respectively, thus confirming the previously assigned r
eceptor types in the cerebellum. (C) 2001 Elsevier Science Ireland Ltd. All
rights reserved.