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Keywords:

  • GABA;
  • Benzodiazepine;
  • t-Butylbicyclophosphorothionate;
  • Antibodies

Abstract: Polyclonal antibodies have been raised against the GABAA/benzodiazepine receptor purified to homogeneity from bovine cerebral cortex in deoxycholate and Triton X-100 media. Radioimmunoassay was applied to measure specific antibody production using the 125I-la-belled -γ-aminobutyric acid (GABA)/benzodiazepine receptor as antigen. The antibodies specifically immuno-precipitated the binding sites for [3H]muscimol and for [3H]flunitrazepam from purified preparations. In addition, when a 3-[(3-cholamidopropyl)dimethylammonio] 1-propanesulphonate (CHAPS) extract of bovine brain membranes was treated with the antibodies, those sites as well as the [3H]propyl-ß-carboline-3-carboxylate binding, the [35S]t-butylbicyclophosphorothionate binding (TBPS), the barbiturate-enhanced [3H]fluni-trazepam binding, and the GABA-enhanced [3H]fluni-trazepam binding were all removed together into the immunoprecipitate. Western blot experiments showed that these antibodies recognise the α-subunit of the purified GABA/benzodiazepine receptor. These results further support the existence in the brain of a single protein, the GABAA receptor, containing a set of regulatory binding sites for benzodiazepines and chloride channel modulators.