Functions of optic nerve glia: axoglial signalling in physiology and pathology
Functions of optic nerve glia: axoglial signalling in physiology and pathology
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DOI：
10.1038/sj.eye.6701595
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发表时间：
2004-11-01
期刊：
影响因子：
3.9
通讯作者：
James, G
中科院分区：
文献类型：
--
作者：
Butt, AM;Pugh, M;James, G
神经胶质功能的早期概念将其设想为被动和不可兴奋的结构元素，就像周围器官的结缔组织一样。现在已知神经胶质具有广泛的生理作用，并对所有形式的病理损伤作出反应。本文综述了少突胶质细胞和星形胶质细胞的主要功能，视神经中的主要类型的胶质细胞，并检查新的NG 2-胶质细胞，也被称为少突胶质细胞祖细胞（OPCs）。少突胶质细胞的主要功能是产生隔离CNS轴突的髓鞘，但它们也在朗维尔结（动作电位传播的位点）和轴突完整性的建立中起重要作用。星形胶质细胞具有多种生理和病理功能，包括钾稳态和代谢，以及对CNS损伤的反应性星形胶质细胞增生。NG 2-胶质细胞的大部分是有丝分裂后的复合细胞，不同于OPC，并且通过快速和刻板的损伤反应对CNS的任何损伤作出反应。这可能是它们的主要功能，但NG 2-胶质细胞，或NG 2表达的成人OPCs的亚群，也提供脱髓鞘后的髓鞘再生少突胶质细胞。少突胶质细胞、星形胶质细胞和NG 2-神经胶质细胞都在郎维氏结处接触轴突，并对轴突电活动期间释放的谷氨酸、ATP和钾作出反应。谷氨酸和ATP在视神经胶质中引起钙信号传导，并且在生理学和病理学中具有双重作用，在正常活动期间将胶质功能与轴突活性偶联，但是增强的活化诱导损伤反应，如在损伤、脱髓鞘和缺血后所见。
An early concept of glial function envisaged them as passive and unexcitable structural elements, much like the connective tissues of organs in the periphery. It is now known that glia have a widespread range of physiological roles and react to all forms of pathological insult. This paper reviews the major functions of oligodendrocytes and astrocytes, the main types of glia in the optic nerve, and examines novel NG2-glia, otherwise known as oligodendrocyte progenitor cells (OPCs). The major function of oligodendrocytes is to produce the myelin sheaths that insulate CNS axons, but they also have important roles in the establishment of nodes of Ranvier, the sites of action potential propagation, and axonal integrity. Astrocytes have multiple physiological and pathological functions, including potassium homeostasis and metabolism, and reactive astrogliosis in response to CNS insults. The bulk of NG2-glia are postmitotic complex cells, distinct from OPCs, and respond to any insult to the CNS by a rapid and stereotypic injury response. This may be their primary unction, but NG2-glia, or a subpopulation of NG2-expressing adult OPCs, also provide remyelinating oligodendrocytes following demyelination. Oligodendrocytes, astrocytes, and NG2-glia all contact axons at nodes of Ranvier and respond to glutamate, ATP, and potassium released during axonal electrical activity. Glutamate and ATP evoke calcium signalling in optic nerve glia and have dual roles in physiology and pathology, coupling glial functions to axonal activity during normal activity, but enhanced activation induces an injury response, as seen following injury, demyelination, and ischaemia.