Division of Glia Disease and Therapeutics, Department of Neurosurgery, Center for Translational Neuromedicine, University of Rochester Medical School, Rochester, NY 14580, USA.
Glia. 2012 Jul;60(7):1013-23. doi: 10.1002/glia.22288. Epub 2012 Jan 6.
The neuronal doctrine, developed a century ago regards neuronal networks as the sole substrate of higher brain function. Recent advances in glial physiology have promoted an alternative hypothesis, which places information processing in the brain into integrated neuronal-glial networks utilizing both binary (neuronal action potentials) and analogue (diffusional propagation of second messengers/metabolites through gap junctions or transmitters through the interstitial space) signal encoding. It has been proposed that the feed-forward and feed-back communication between these two types of neural cells, which underlies information transfer and processing, is accomplished by the release of neurotransmitters from neuronal terminals as well as from astroglial processes. Understanding of this subject, however, remains incomplete and important questions and controversies require resolution. Here we propose that the primary function of perisynaptic glial processes is to create an "astroglial cradle" that shields the synapse from a multitude of extrasynaptic signaling events and provides for multifaceted support and long-term plasticity of synaptic contacts through variety of mechanisms, which may not necessarily involve the release of "glio" transmitters.
一个世纪以前提出的神经元学说认为，神经网络是大脑高级功能的唯一基础。近年来神经胶质生理学的进展提出了另一种假说，即将大脑中的信息处理纳入整合的神经元-神经胶质网络，利用二元（神经元动作电位）和模拟（通过缝隙连接或通过间质空间的递质扩散传播的第二信使/代谢物）信号编码。有人提出，这两种类型的神经细胞之间的前馈和反馈通讯是通过神经元末梢以及星形胶质细胞过程中神经递质的释放来完成的，信息传递和处理就是由此实现的。然而，对这一主题的理解仍不完整，需要解决一些重要的问题和争议。在这里，我们提出，突触周围胶质过程的主要功能是创建一个“星形胶质细胞摇篮”，将突触与大量的突触外信号事件隔离开来，并通过多种机制为突触接触提供多方面的支持和长期的可塑性，这些机制不一定涉及“胶质”递质的释放。
