Characterization of novel benzodiazepine ligands in Spodotera frugiperda (Sf-9) insect cells

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.