Identification of a vesicular glutamate transporter that defines a glutamatergic phenotype in neurons
Identification of a vesicular glutamate transporter that defines a glutamatergic phenotype in neurons
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DOI：
10.1038/35025070
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发表时间：
2000-09-14
期刊：
影响因子：
64.8
通讯作者：
Jahn, R
中科院分区：
文献类型：
--
作者：
Takamori, S;Rhee, JS;Jahn, R
谷氨酸是哺乳动物中枢神经系统中主要的兴奋性神经递质。突触囊泡通过特定的囊泡转运体装载神经递质。本研究表明，BNPI是一种与钠依赖性磷酸盐运输相关的囊泡结合转运蛋白（1-3），其表达可导致细胞内囊泡摄取谷氨酸。底物特异性和能量依赖性与突触囊泡摄取谷氨酸非常相似。刺激胞吐-囊泡与细胞膜融合并释放其内容物-导致表达bnpi的细胞大量释放谷氨酸。此外，我们在含有GABA （γ -氨基丁酸）的神经元中表达BNPI，并将其作为形成突触的单个分离神经元的培养物进行维护。在刺激这些神经元后，突触后电流的一个组成部分由谷氨酸介导，因为它被谷氨酸受体拮抗剂的组合阻断，但对GABA(a)受体拮抗剂不敏感。我们得出的结论是，BNPI作为谷氨酸囊泡转运体发挥作用，并且BNPI的表达足以定义神经元中的谷氨酸能表型。
Glutamate is the major excitatory neurotransmitter in the mammalian central nervous system. Synaptic vesicles are loaded with neurotransmitter by means of specific vesicular transporters. Here we show that expression of BNPI, a vesicle-bound transporter associated with sodium-dependent phosphate transport(1-3), results in glutamate uptake by intracellular vesicles. Substrate specificity and energy dependence are very similar to glutamate uptake by synaptic vesicles. Stimulation of exocytosis-fusion of the vesicles with the cell membrane and release of their contents-resulted in quantal release of glutamate from BNPI-expressing cells. Furthermore, we expressed BNPI in neurons containing GABA (gamma-aminobutyric acid) and maintained them as cultures of single, isolated neurons that form synapses to themselves. After stimulation of these neurons, a component of the postsynaptic current is mediated by glutamate as it is blocked by a combination of the glutamate receptor antagonists, but is insensitive to a GABA(A) receptor antagonist. We conclude that BNPI functions as vesicular glutamate transporter and that expression of BNPI suffices to define a glutamatergic phenotype in neurons.