Binding of radioactive gamma-aminobutyric acid to homogenates of mammalian brain was detected by a centrifugation assay. The binding capacity of the tissue was maximal and stable with time only if the tissue was thoroughly washed to remove an endogenous inhibitor of binding. With such washed tissue, binding to total rat or cow brain appeared to involve two populations of sites in the absence of sodium ions, the major site having a dissociation constant of 150 nM and saturating at 80 pmol/g brain, and a minor site with a KD of 20 nM and saturating at 20 pmol/g wet tissue. This sodium-independent GABA binding as a whole was localized in the crude mitochondrial, microsomal, and synaptosomal membrane fractions.
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
- Pharmacology, Toxicology and Pharmaceutics(all)