Lactate/pyruvate transport between glial cells and neurons is thought to play an important role in how brain cells sustain the high-energy demand that neuronal activity requires. However, the in vivo mechanisms and characteristics that underlie the transport of monocarboxylates are poorly described. Here, we use Drosophila expressing genetically encoded FRET sensors to provide an ex vivo characterization of the transport of monocarboxylates in motor neurons and glial cells from the larval ventral nerve cord. We show that lactate/pyruvate transport in glial cells is coupled to protons and is more efficient than in neurons. Glial cells maintain higher levels of intracellular lactate generating a positive gradient toward neurons. Interestingly, during high neuronal activity, raised lactate in motor neurons is dependent on transfer from glial cells mediated in part by the previously described monocarboxylate transporter Chaski, providing support for in vivo glia-to-neuron lactate shuttling during neuronal activity.

中文翻译：

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神经元乳酸水平取决于果蝇大脑高活动期间神经胶质来源的乳酸。

胶质细胞和神经元之间的乳酸/丙酮酸转运被认为在脑细胞如何维持神经元活动所需的高能量需求方面发挥着重要作用。然而，作为单羧酸盐转运基础的体内机制和特征的描述很少。在这里，我们使用果蝇表达基因编码的 FRET 传感器来提供运动神经元和胶质细胞中单羧酸盐从幼虫腹神经索的转运的离体表征。我们表明，胶质细胞中的乳酸/丙酮酸转运与质子耦合，并且比神经元更有效。神经胶质细胞保持较高水平的细胞内乳酸，产生朝向神经元的正梯度。有趣的是，在高神经元活动期间，