EXPRESSION OF GAT-1, A HIGH-AFFINITY GAMMA-AMINOBUTYRIC-ACID PLASMA-MEMBRANE TRANSPORTER IN THE RAT RETINA
EXPRESSION OF GAT-1, A HIGH-AFFINITY GAMMA-AMINOBUTYRIC-ACID PLASMA-MEMBRANE TRANSPORTER IN THE RAT RETINA
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DOI：
10.1002/cne.903450410
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发表时间：
1994-07-22
影响因子：
2.5
通讯作者：
WEIGMANN, C
中科院分区：
文献类型：
--
作者：
BRECHA, NC;WEIGMANN, C
γ-氨基丁酸（GABA）质膜转运蛋白通过高亲和力、Na+依赖性转运过程影响突触传递。的cDNA克隆，GAT-1，编码高亲和力Na+和Cl-依赖的GABA质膜转运蛋白，其动力学和药理学特性类似的高亲和力GABA摄取系统与神经元。本研究通过RNA印迹杂交和原位杂交组织化学方法评价了这种假定的神经元GABA转运体在大鼠视网膜中的分布和细胞定位。视网膜和小脑总RNA提取物的北方印迹杂交分析显示在4.2倍酶处有一条杂交带。GABA转运蛋白mRNA由分布于近端内核层和神经节细胞层的大量细胞以及位于内网状层的少数细胞表达。结合荧光染料Fluorogold从上级丘逆行运输，以确定神经节细胞和原位杂交组织化学的双标记研究表明，大多数GAT-1 mRNA的细胞在神经节细胞层的位移无长突细胞，虽然一些含有GAT-1 mRNA的神经节细胞可视化。在新鲜分离的视网膜细胞制备物中，GAT-1 RNA信号在神经元中较强，在称为Muller细胞的专门胶质细胞中较弱至中等。Muller细胞通过其形态和选择性Muller细胞标志物细胞视网膜色素脱结合蛋白的存在来鉴定。在组织切片和分离的视网膜细胞制备物中，仅观察到有义GAT-1 RNA探针的背景标记。这些发现表明，GAT-1 mRNA在视网膜和脑中均有表达。在视网膜中，这种转运蛋白主要定位于无长突细胞、移位的无长突细胞和网间细胞以及一些神经节细胞。这种转运蛋白mRNA也由Muller细胞表达，但水平低于神经元。这些观察结果表明，GABA的运输GAT-1质膜转运蛋白在视网膜中是由神经元和神经胶质细胞介导的。(C)1994 Wiley-Liss，Inc.
Gamma-aminobutyric acid (GABA) plasma membrane transporters influence synaptic transmission by high-affinity, Na+-dependent transport processes. The cDNA clone, GAT-1, encodes a high-affinity Na+- and Cl- -dependent GABA plasma membrane transporter, which has kinetic and pharmacological properties similar to those of high-affinity GABA uptake systems associated with neurons. The present study evaluates the distribution and cellular localization of this putative neuronal GABA transporter by RNA blot hybridization and in situ hybridization histochemistry in the rat retina. Northern blot hybridization analysis of total retinal and cerebellar RNA extracts demonstrated a single band of hybridization at 4.2 kilobases. GABA transporter mRNA is expressed by numerous cells that are distributed to the proximal inner nuclear layer and the ganglion cell layer and by a few cells located in the inner plexiform layer. Double label studies combining the retrograde transport of the fluorescent dye Fluorogold from the superior colliculus to identify ganglion cells and in situ hybridization histochemistry demonstrated that most GAT-1 mRNA-containing cells in the ganglion cell layer are displaced amacrine cells, although some ganglion cells containing GAT-1 mRNA were visualized. In freshly dissociated retinal cell preparations, the GAT-1 RNA signal is strong in neurons and weak to moderate in specialized glial cells called Muller cells. Muller cells were identified by both their morphology and the presence of the selective Muller cell marker cellular retinaldehyde-binding protein. Only background labeling is seen with the sense GAT-1 RNA probe in both tissue sections and dissociated retinal cell preparations. These findings demonstrate that GAT-1 mRNA is expressed in both the retina and brain. In the retina, this transporter is predominantly localized to amacrine, displaced amacrine and interplexiform cells, and some ganglion cells. This transporter mRNA is also expressed by Muller cells but at a lower level than by neurons. These observations indicate that GABA transport by GAT-1 plasma membrane transporters in the retina is mediated by both neurons and glia cells. (C) 1994 Wiley-Liss, Inc.