Solubilization of convulsant/barbiturate binding activity on the γ-aminobutyric acid/benzodiazepine receptor complex

Binding activity of the radioactive cage convulsant [ 35S] t-butyl-bicyclophosphorothionate was solubilized from rat brain membranes using the zwitterionic detergent 3-[(3-cholamidopropyl)-dimethylammonio] propanesulfonate. Binding (K D = 26 nM, Bmax = 0.4 pmol/mg protein) was inhibited by picrotoxin and related convulsants and by barbiturates and related depressants that interact with γ-aminobutyric acid and benzodiazepine receptors via the picrotoxinin binding site. The convulsant/ barbiturate binding activity chromatographed on gel filtration as a single peak coinciding with the benzodiazepine/γ-aminobutyric acid receptor protein complex.