Abstract:Antibodies raised against the synthetic peptide NH2‐QKSDDDYEDYASNKTC‐COOH (γ2 1–15 Cys), which corresponds to the N‐terminal amino acid sequence with a C‐terminal cysteine of the human γ2 subunit of the γ‐aminobutyric acidA(GABAA) receptor, were used to study the quantitative immunoprecipitation of agonist benzodiazepine binding sites from bovine brain. Anti‐γ2 1–15 Cys antibodies were found to immunoprecipitate specifically in parallel [3H]flunitrazepam‐ and [3H]muscimol‐reversible binding sites in a dose‐dependent manner. The maximum percentages of [3H]flunitrazepam binding sites immunoprecipitated from detergent extracts of bovine cerebral cortex, cerebellum, and hippocampus were 68, 77, and 83%, respectively. Immunoprecipitation studies with anti‐α1 324–341 antibodies carried out in parallel with anti‐γ2 1–15 Cys antibodies provided evidence for the promiscuity of the γ2 subunit within native GABAAreceptors. These results substantiate the association of the γ2 p