Single class of muscimol binding sites in the solubilized gamma-aminobutyrate-benzodiazepine receptor complex.

The gamma-aminobutyrate-benzodiazepine receptor complex was solubilized from the rat brain and bovine cortex and partially purified by means of gel chromatography. Analysis of binding parameters of [3H]muscimol indicates that the complex includes only one class of binding sites which presumably represent an apparently low affinity class of two classes of gamma-aminobutyrate A receptors described on the brain membranes. Analysis of the [3H] flunitrazepam specific binding also shows the presence of one class of binding sites sensitive to gamma-aminobutyrate stimulation. The concentration of muscimol binding sites in the gamma-aminobutyrate-benzodiazepine receptor complex was observed to be twice as high as the concentration of benzodiazepine binding sites.