光敏感通道(Channelrhodopsin-2)——神经回路功能和神经系统疾病研究的新工具

光敏感通道(channelrhodopsin-2,ChR2)是一种受光脉冲控制的具有7次跨膜结构的非选择性阳离子通道蛋白,自1991年从莱茵衣藻中发现后被许多实验室所关注.依据ChR2可以快速形成光电流,使细胞发生去极化反应的电生理特性,ChR2已被广泛应用于神经系统的研究.与传统的神经系统研究方法如电生理技术、神经药理学方法相比,用光脉冲控制带有ChR2的神经元的活动,具有更高的空间选择性和特异性.ChR2作为光基因技术的核心组成部分,对神经科学是一个崭新的应用前景广泛的研究工具.近年来ChR2不仅应用于视觉、躯体感觉、听觉和嗅觉等多条感觉神经回路的形态和功能研究,还被应用于各种临床神经系统疾病的研究.本文总结了目前ChR2在神经系统中的研究进展,并对ChR2未来的应用前景作了进一步展望.

ChR2 is a Novel Tool for Studying Neural Circuitsand Nervous System Diseases

Channelrhodopsin-2(ChR2), a directly light-activated cation-selective ion channel, is a seven-transmembrane (7-TM) helix protein isolated from Chlamydomonas reinhardtii, and contains the light-isomerizable chromophore all-trans-retinal. ChR2 opens rapidly after absorption of a photon to generate photocurrent. When it was expressed in excitable cells using a variety of transfection techniques, ChR2 makes depolarization of the excitable cells very straightforward after stimulated by blue light. It is useful for many bioengineering and neuroscience applications, such as control of neuronal firing for probing of neural circuits. Compared with the traditional electrophysiological technique and the pharmaceutical methods, ChR2 has the higher selectivity and specificity. The emerging field of controlling networks of genetically modified cells by light has been termed optogenetics. ChR2, a critical component of optogenetics, is a novel promising tool for neuroscience research. ChR2 has been applied to many aspects of nervous system research, such as visual neural circuit, tactual neural circuit, auditory neural circuit and olfactory neural circuit, as well as some nervous system disease research. The review highlights the recent advances of ChR2 in the study of nervous system, prospecting its future profile.