Barros L F, Courjaret R, Jakoby P, Loaiza A, Lohr C, Deitmer J W
Centro de Estudios Científicos (CECS), Valdivia, Chile.
Glia. 2009 Jul;57(9):962-70. doi: 10.1002/glia.20820.
Knowing how different cell types handle glucose should help to decipher how energy supply is adjusted to energy demand in the brain. Previously, the uptake of glucose by cultured brain cells was studied in real-time using fluorescent tracers and confocal microscopy. Here, we have adapted this technique to acute slices prepared from the rat cerebellum by means of multiphoton microscopy. The transport of the fluorescent glucose analogs 2NBDG and 6NBDG was several-fold faster in the molecular layer of the cerebellar cortex than in Purkinje cell somata and granule cells. After washout of free tracer, it became apparent that most phosphorylated tracer was located in Bergmann glia, which was confirmed by counterstaining with the glial marker sulforhodamine 101. The effective recovery of fluorescence after photobleaching showed that 2NBDG-P can diffuse horizontally across the molecular layer, presumably through gap junctions between Bergmann glial cells. Our main conclusion is that in acute cerebellar slices, the glucose transport capacity and glycolytic rate of Bergmann glia are several-fold higher than those of Purkinje cells. Given that the cerebellum is largely fueled by glucose and Purkinje neurons are estimated to spend more energy than Bergmann glial cells, these results suggest substantial shuttling of an energy-rich metabolite like lactate between glial cells and neurons.
了解不同细胞类型如何处理葡萄糖，应有助于解读大脑中能量供应是如何根据能量需求进行调整的。此前，利用荧光示踪剂和共聚焦显微镜对培养的脑细胞摄取葡萄糖的过程进行了实时研究。在此，我们通过多光子显微镜技术，将该技术应用于从大鼠小脑中制备的急性切片。荧光葡萄糖类似物2NBDG和6NBDG在小脑皮质分子层中的转运速度比在浦肯野细胞胞体和颗粒细胞中快几倍。在洗去游离示踪剂后，很明显大部分磷酸化示踪剂位于伯格曼胶质细胞中，这通过用胶质细胞标记物磺基罗丹明101进行复染得到了证实。光漂白后荧光的有效恢复表明，2NBDG-P可能通过伯格曼胶质细胞之间的缝隙连接在分子层中水平扩散。我们的主要结论是，在急性小脑切片中，伯格曼胶质细胞的葡萄糖转运能力和糖酵解速率比浦肯野细胞高几倍。鉴于小脑主要由葡萄糖提供能量，并且据估计浦肯野神经元比伯格曼胶质细胞消耗更多能量，这些结果表明像乳酸这样富含能量的代谢物在胶质细胞和神经元之间大量穿梭。
