Kinetic evaluation of photosensitivity in genetically engineered neurons expressing green algae light-gated channels
Kinetic evaluation of photosensitivity in genetically engineered neurons expressing green algae light-gated channels
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DOI：
10.1016/j.neures.2005.10.009
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发表时间：
2006-02-01
影响因子：
2.9
通讯作者：
Yawo, H
中科院分区：
文献类型：
--
作者：
Ishizuka, T;Kakuda, M;Yawo, H
神经元通过遗传方式引入一种绿藻来源的蛋白-通道视紫红质-2 （ChR2）而变得光敏。在此，我们定量研究了蓝光发光二极管（LED）在pc12细胞中表达ChR2的光门控电流的快速性。光门控电流由灭活和非灭活两个分量组成，灭活分量的大小与光强几乎成线性关系。非灭活成分在高照度下呈现饱和的趋势。光门控电流的激活率和失活率均与光强呈线性关系。然而，激活率（开启率）大约比失活率快10倍。虽然关断时间常数与光强的关系不大，但其光脉冲末端的关断时间常数比20英寸处的关断时间常数大约两倍。在活体动物中，ChR2的表达也使神经元具有光敏性。由于光门控电流的开启和关闭时间常数均小于神经元的膜时间常数，因此LED光照射光敏神经元足以在海马急性区以脉冲对脉冲的方式唤起动作电位。(c) 2005爱思唯尔爱尔兰有限公司和日本神经科学学会。版权所有。
Neurons become photosensitive by genetically introducing one of green algae-derived protein, channelrhodopsin-2 (ChR2). Here, we quantitatively investigated the rapidness of the light-gated current of ChR2 expressed in PC 12 cells using blue light-emitting diode (LED) light. The light-gated current consists of two components, inactivating and non-inactivating The magnitude of inactivating component was almost linearly related to the light intensity. The non-inactivating component showed a tendency to saturate at high illumination. Both the activation and inactivation rates of the light-gated current were linearly dependent on the light intensity. However, the activation rate (turning-on rate) is about 10-fold faster than the inactivation rate. Although the turning-off time constant was little dependent on the light intensity, that at the end of Is light pulse was about two-fold larger than that at 20 ins. Neurons are also made photosensitive by the expression of ChR2 in the living animal. Since both the turning-on and turning-off time constants of light-gated current was smaller than the membrane time constant of neurons, the LED light illumination of the photosensitive neurons was enough to evoke action potentials in a pulse-to-pulse manner in an acute slice of hippocampus. (c) 2005 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.