脑糖原在脑能量代谢中的作用研究进展

The function research progress of cerebral glycogen in brain energy metabolism

脑糖原的含量远远小于肝糖原和肌糖原,但却是脑葡萄糖含量的几倍。脑糖原浓度可高达10μmol.g-1,大大超乎人们以往的认识。目前对于脑糖原的作用还不完全清楚,其含量受到神经递质、激素、神经元活动等因素影响。现阶段的研究表明,脑糖原是非常重要的脑能量储备和脑活动的物质基础。脑糖原主要储存于星形胶质细胞中,是神经元活动的主要能量来源。在睡眠和麻醉时积累脑糖原,清醒时消耗脑糖原,特别是神经元轴突活动激烈时迅速消耗脑糖原。在胰岛素诱发低血糖或脑缺血时,血源性葡萄糖供应不足,星形胶质细胞中糖原源性乳酸为神经元的活动和生存提供能量。糖原异常还可引起抑郁症、糖原贮积病、阿尔采末病、癫痫和拉福拉病等疾病。

Cerebral glycogen content is far less than the liver gly- cogen and muscle glycogen, but it is several times of cerebral glucose levels. Cerebral glycogen concentration can be as high as 10 micromole/g, greatly beyond the understanding of people in the past. For now the role of cerebral glycogen is not yet fully understood, its content is influenced by neurotransmitter, bor-mone, neuron activities,etc. Current research shows that cerebral glycogen is very important brain energy reserves and brain activi- ty material foundation. Cerebral glycogen is mainly stored in as- trocytes, which is the main source of energy of neuron activities. Time of sleep and anesthesia accumulates cerebral glycogen, but awaking time consumes cerebral glycogen , especially neuron axons intense activity quickly consumes cerebral glycogen. When the insulin induced hypoglycemia or cerebral ischemia, blood-borne glucose is in short supply, glycogen source lactic acid in astrocytes provides energy for neurons activities and sur- vival. Glycogen abnormality can also cause depression, glycog-enosis, Alzheimer＇ s disease, epilepsy, Lafora＇ s disease and other diseases.