粗制突触膜上γ-氨基丁酸结合位点的表征

Characterization of gamma-aminobutyric acid binding sites on crude synaptic membranes.

作者信息

Kurioka S, Hayata H, Matsuda M

出版信息

J Neurochem. 1981 Aug;37(2):283-8. doi: 10.1111/j.1471-4159.1981.tb00453.x.

DOI:10.1111/j.1471-4159.1981.tb00453.x

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.

摘要

为了在存在钠离子的情况下鉴定γ-氨基丁酸（GABA）与其突触受体的结合，对[³H]GABA与大鼠脑粗制突触膜的结合进行了研究。从粗制突触膜组分制备的膜囊泡可作为区分突触GABA受体和GABA摄取位点的工具。在不存在钠离子的情况下，用 Triton X-100处理的粗制突触膜（膜（TX））涉及两类GABA结合位点（解离常数KD = 38.7和78.0 nM），但在存在钠离子的情况下，高亲和力位点消失，检测到单一类别的GABA结合位点（KD = 75.0 nM）。未检测到[³H]GABA被主动摄取到由膜（TX）制备的囊泡中，这表明在存在钠离子的情况下[³H]GABA结合与突触GABA受体有关。钠离子可能会掩盖高亲和力类GABA受体的存在。