二氨基丁酸：一种用于区分突触小体中 GABA 载体介导和非载体介导释放的工具？

Diaminobutyric acid: A tool for discriminating between carrier-mediated and non-carrier-mediated release of GABA from synaptosomes?

机构信息

Laboratorio di Biologia Cellulare, CNR, Via Romagnosi 18/A, Rome, Italy.

出版信息

Neurochem Res. 1976 Dec;1(6):581-90. doi: 10.1007/BF00965600.

Abstract

The carrier-mediated transport of GABA in rat brain synaptosomes was strongly and permanently inhibited byL-2,4-diaminobutyric acid (DAB). In order to discriminate between carrier-mediated and non-carrier-mediated release of [(3)H]GABA, synaptosomes prelabeled with 0.5 μM [(3)H]GABA in the presence of 100 μM DAB, or with 0.2 μM [(3)H]GABA without DAB, were superfused in conditions stimulating the release of [(3)H]GABA. Only the release elicited by unlabeled GABA or DAB (by homo- and heteroexchange, respectively) was strongly inhibited in DAB-pretreated synaptosomes. The spontaneous release and the release induced by 56 mM KCl in the presence of CaCl2, by the ionophore A23187, by ouabain, by lack of K(+), or by purified black widow spider toxin were unaffected or only barely decreased in DAB-treated synaptosomes, and therefore do not seem to be mediated by the DAB-blocked GABA carrier.

摘要

在大鼠脑突触体中，L-2,4-二氨基丁酸（DAB）强烈且永久地抑制 GABA 的载体介导转运。为了区分 [(3)H]GABA 的载体介导和非载体介导释放，在存在 100 μM DAB 的情况下用 0.5 μM [(3)H]GABA 预标记突触体，或用 0.2 μM [(3)H]GABA 而无 DAB，在刺激 [(3)H]GABA 释放的条件下进行超滤液。只有用未标记的 GABA 或 DAB（分别通过同型和异型交换）引发的释放在 DAB 预处理的突触体中受到强烈抑制。在 CaCl2 存在下，用离子载体 A23187、哇巴因、缺乏 K+或用纯化的黑寡妇蜘蛛毒素引发的自发释放以及由 56 mM KCl 引发的释放，在 DAB 处理的突触体中不受影响或仅略有减少，因此似乎不是由 DAB 阻断的 GABA 载体介导的。