Characterization of γ‐Aminobutyric Acid Binding Sites on Crude Synaptic Membranes

Publisher Website
Google Scholar
Abstract
[3H]GABA binding to crude synaptic membranes of rat brain was studied in an attempt to identify GABA binding to its synaptic receptor in the presence of Na+. Membrane vesicles prepared from crude synaptic membrane fractions were useful as a tool to differentiate synaptic GABA receptors from GABA uptake sites. The crude synaptic membranes treated with Triton X‐100 [membranes (TX)] involved two classes of GABA binding sites (KD= 38.7 and 78.0 nM) in the absence of Na+, but the high‐affinity sites disappeared in the presence of Na+ and a single class of GABA binding sites (KD= 75.0 nM) was detected. The failure to detect an active uptake of [3H]GABA into the vesicles prepared from membranes (TX) suggests that the [3H]GABA binding in the presence of Na+ was related to synaptic GABA receptors. It is probable that Na+ could mask the presence of the high‐affinity class of GABA receptor.

This publication has 13 references indexed in Scilit: