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了解不同类型的细胞如何处理葡萄糖有助于解释能量供应是如何是如何根据大脑能量需求来进行调整的。荧光追踪结合共聚焦显微镜技术已用于研究培养的脑细胞摄取葡萄糖的实时动态过程。本文采用这种技术利用多光子显微镜观察急性制备的大鼠小脑脑片。带荧光的葡萄糖类似物2NBDG和6NBDG在小脑皮质的分子层中的转运速度比其在蒲肯野细胞胞体和颗粒细胞中快若干倍。洗脱游离示踪剂后,可见大部分磷酸化示踪剂都位于Bergmann胶质细胞,用胶质细胞标记物sulforhodamine 101免疫染色后进一步确认这一结果。有效回收荧光光漂白后显示,2NBDG-P可通过Bergmann胶质细胞之间的缝隙连接沿着分子层水平扩散。本文的结果表明在急性小脑切片中,Bergmann胶质细胞对葡萄糖的转运能力和糖酵解率高于蒲肯野细胞若干倍。由于小脑主要由葡萄糖提供能量,蒲肯野神经元被认为比Bergmann胶质细胞更耗能量,这些结果表明,在胶质细胞和神经元之间存在类似乳酸的能量代谢物介导的环路。
Understanding how different types of cells handle glucose helps explain how the energy supply is tuned to the energy needs of the brain. Fluorescence tracing combined with confocal microscopy has been used to study the real-time dynamics of glucose uptake by cultured brain cells. This article uses this technique to examine acutely prepared rat cerebellar slices using multiphoton microscopy. Fluorescent glucose analogues 2NBDG and 6NBDG are transported several times faster in the molecular layers of the cerebellar cortex than they do in Purkinje cell soma and granulosa cells. After elution of the free tracers, most of the phosphorylated tracers were found in Bergmann glia, further confirmed by immunostaining with the glial cell marker sulforhodamine 101. Efficient recovery of fluorescent photobleaching revealed that 2NBDG-P diffused horizontally along molecular layers through gap junctions between Bergmann glia. Our results show that Bergmann glial cells are more capable of transporting glucose and glycolysis than Purkinje cells in acute cerebellar sections. Since the cerebellum is primarily powered by glucose, Purkinje neurons are considered more energy-consuming than Bergmann glia, and these results suggest that there is a lactate-like energy metabolite-mediated loop between glia and neurons.