Some GABAAR in synaptosomal plasma membrane are associated with DRMs. The SPM fraction was extracted by 1% Triton X-100 at 4°C and the soluble (TS) and insoluble (TI) fractions were collected. The low-density DRM fraction was also collected after flotation in a discontinuous sucrose gradient. A: Immunoblots with rabbit antibodies to α1, α2, β2, β3, γ2 GABAAR subunits, gephyrin, transferrin receptor (TrsfR) and lipid raft markers Thy-1, Caveolin-1 and Flotillin-1. Same amount of total protein (4μg/lane) was used for SDS-PAGE. B: [3H]MUS and [3H]FNZ binding to GABAARs in TS, TI and DRM. Specific activity values (pmol/mg protein) are mean ± S.E.M of at least three experiments each done in triplicate. *** p < 0.001; ** p < 0.01. The p values are for the TS or TI fractions compared to DRM.