Barros L Felipe, Deitmer Joachim W
Centro de Estudios Científicos (CECS), Valdivia, Chile.
Brain Res Rev. 2010 May;63(1-2):149-59. doi: 10.1016/j.brainresrev.2009.10.002. Epub 2009 Oct 30.
The main source of energy for the mammalian brain is glucose, and the main sink of energy in the mammalian brain is the neuron, so the conventional view of brain energy metabolism is that glucose is consumed preferentially in neurons. But between glucose and the production of energy are several steps that do not necessarily take place in the same cell. An alternative model has been proposed that states that glucose preferentially taken by astrocytes, is degraded to lactate and then exported into neurons to be oxidized. Short of definitive data, opinions about the relative merits of these competing models are divided, making it a very exciting field of research. Furthermore, growing evidence suggests that lactate acts as a signaling molecule, involved in Na(+) sensing, glucosensing, and in coupling neuronal and glial activity to the modulation of vascular tone. In the present review, we discuss possible dynamics of glucose and lactate in excitatory synaptic regions, focusing on the transporters that catalyze the movement of these molecules.
哺乳动物大脑的主要能量来源是葡萄糖，而大脑中主要的能量消耗部位是神经元，因此传统的脑能量代谢观点认为葡萄糖优先在神经元中被消耗。但是在葡萄糖与能量产生之间有几个步骤，这些步骤不一定在同一个细胞中发生。有人提出了另一种模型，该模型认为优先被星形胶质细胞摄取的葡萄糖会被降解为乳酸，然后输出到神经元中进行氧化。由于缺乏确凿的数据，对于这些相互竞争的模型的相对优点，各方观点不一，这使得它成为一个非常令人兴奋的研究领域。此外，越来越多的证据表明，乳酸作为一种信号分子，参与钠（Na⁺）感知、葡萄糖感知，以及将神经元和神经胶质细胞的活动与血管张力调节相耦合。在本综述中，我们讨论了兴奋性突触区域中葡萄糖和乳酸可能的动态变化，重点关注催化这些分子转运的转运体。
