Binding of muscimol and GABA in sub-fractions of a crude membrane fraction of rat brain

Abstract

The binding of [ 3H]γ-aminobutyric acid ([ 3H]GABA) and [ 3H]muscimol to subcellular particles of brain, which occurs in the absence of added Na + (i.e., “Na +-independent binding”), has been used to estimate synaptic GABA-receptors (1–3). This binding appears to be most enriched in crude synaptic membrane fractions of brain (4–6), but all of the binding sites do not appear to be localized to synaptic membranes (e.g., 2,7,8). Recent studies have revealed further that the highest-affinity process for [ 3H]muscimol binding to subcellular particles of rat brain has a higher capacity than that of [ 3H]GABA (9–12). Herein, the binding of these ligands to sub-fractions of a crude membrane fraction of rat brain are compared.