Analysis of the cell surface expression of GABAAR subunits was carried out using a cell-surface biotinylation assay. The levels of biotinylated α1, α4, β2/3 or γ2 subunits were determined by western blot. (A) Representative blots of α1, α4, β2/3, γ2 or actin immunoreactivity in total cell lysate, and cell surface or intracellular fractions. (B) GABAAR immunoreactivity was normalized to the actin signal detected in the corresponding lysate fraction and expressed as percentage of control. Bars represent the normalized values for BDNF treated cells. Control values are 100%. No increase in levels of GABAAR subunits was observed, suggesting that BDNF does not increase the cell surface levels of GABAAR.