Physiological requirement for the glutamate transporter dEAAT1 at the adult Drosophila neuromuscular junction
Physiological requirement for the glutamate transporter dEAAT1 at the adult Drosophila neuromuscular junction
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DOI：
10.1002/neu.20270
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发表时间：
2006-09-01
期刊：
影响因子：
--
通讯作者：
Birman, Serge
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文献类型：
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作者：
Rival, Thomas;Soustelle, Laurent;Birman, Serge
L-谷氨酸是哺乳动物大脑中主要的兴奋性神经递质。Na+/K+依赖性高亲和力兴奋性氨基酸转运蛋白（EAAT）参与了这种氨基酸的细胞外清除和再循环。果蝇神经肌肉接头（NNIJ）的I型突触类似地使用L-谷氨酸作为兴奋性递质。然而，在果蝇中唯一的高亲和力谷氨酸再摄取转运蛋白dEAAT 1在NMJ的定位和功能尚不清楚。使用特定的抗体和转基因菌株，我们观察到，dEAAT 1是存在于成人，但令人惊讶的是，没有在胚胎和幼虫NMJ，这表明在变态过程中的交界处的生理成熟。我们发现，dEAAT 1是不是本地化的运动神经元，但在胶质细胞的延伸，密切遵循运动轴突的成年NMJ。通过RNA干扰使dEAAT 1基因失活产生了能够行走但飞行缺陷的可行成年苍蝇。在成年dEAAT 1缺陷果蝇中进行胸背外侧NMJ的电生理记录。缺乏dEAAT 1延长了个体对运动神经刺激的反应的持续时间，并且这种效应在刺激的生理训练期间逐渐增加。因此，需要神经胶质细胞的谷氨酸再摄取来确保果蝇NMJ的正常活性，但仅限于成年果蝇。(c)2006 Wiley Periodicals，Inc. J Neurobiol 66：1061-1074，2006.
L-Glutamate is the major excitatory neurotransmitter in the mammalian brain. Specific proteins, the Na+/K+-dependent high affinity excitatory amino acid transporters (EAATs), are involved in the extracellular clearance and recycling of this amino acid. Type I synapses of the Drosophila neuromuscular junction (NNIJ) similarly use L-glutamate as an excitatory transmitter. However, the localization and function of the only high-affinity glutamate reuptake transporter in Drosophila, dEAAT1, at the NMJ was unknown. Using a specific antibody and transgenic strains, we observed that dEAAT1 is present at the adult, but surprisingly not at embryonic and larval NMJ, suggesting a physiological maturation of the junction during metamorphosis. We found that dEAAT1 is not localized in motor neurons but in glial extensions that closely follow motor axons to the adult NMJ. Inactivation of the dEAAT1 gene by RNA interference generated viable adult flies that were able to walk but were flight-defective. Electro-physiological recordings of the thoracic dorso-lateral NMJ were performed in adult dEAAT1-deficient flies. The lack of dEAAT1 prolonged the duration of the individual responses to motor nerve stimulation and this effect was progressively increased during physiological trains of stimulations. Therefore, glutamate reuptake by glial cells is required to ensure normal activity of the Drosophila NMJ, but only in adult flies. (c) 2006 Wiley Periodicals, Inc. J Neurobiol 66: 1061-1074, 2006.