Astrocyte glycogen and brain energy metabolism
Astrocyte glycogen and brain energy metabolism
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DOI：
10.1002/glia.20557
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发表时间：
2007-09-01
期刊：
影响因子：
6.2
通讯作者：
Ransom, Bruce R.
中科院分区：
文献类型：
--
作者：
Brown, Angus M.;Ransom, Bruce R.
大脑含有糖原，但与肝脏和肌肉相比，浓度低。在成年大脑中，糖原主要在星形胶质细胞中发现。星形胶质细胞糖原含量受许多因素调节，包括一些神经递质和环境葡萄糖浓度。令人信服的证据表明，在低血糖期间，星形胶质细胞糖原分解至乳酸，该乳酸转移到相邻的神经元或轴突中，该神经元或轴突被用作燃料。对于CNS白质，这种能源可以将轴突功能扩展20分钟或更长时间。同样，在能量需求超过葡萄糖供应的强烈神经活动期间，星形胶质细胞糖原被降解为乳酸，其中一部分被转移到轴突中以获取燃料。因此，星形胶质细胞糖原提供了一些防止降血糖神经损伤的保护，并确保神经元和轴突可以在非常激活的激活期间保持其功能。这些关于星形胶质细胞糖原的作用的新兴原则与长期以来的信念相矛盾，即这种代谢池几乎没有或没有功能意义。 （c）2007 Wiley-Liss，Inc。
The brain contains glycogen but at low concentration compared with liver and muscle. In the adult brain, glycogen is found predominately in astrocytes. Astrocyte glycogen content is modulated by a number of factors including some neurotransmitters and ambient glucose concentration. Compelling evidence indicates that astrocyte glycogen breaks down during hypoglycemia to lactate that is transferred to adjacent neurons or axons where it is used aerobically as fuel. In the case of CNS white matter, this source of energy can extend axon function for 20 min or longer. Likewise, during periods of intense neural activity when energy demand exceeds glucose supply, astrocyte glycogen is degraded to lactate, a portion of which is transferred to axons for fuel. Astrocyte glycogen, therefore, offers some protection against hypoglycemic neural injury and ensures that neurons and axons can maintain their function during very intense periods of activation. These emerging principles about the roles of astrocyte glycogen contradict the long held belief that this metabolic pool has little or no functional significance. (C) 2007 Wiley-Liss, Inc.