Layer-specific modulation of neuronal excitability by 660-nm laser irradiation in mouse neocortex
Layer-specific modulation of neuronal excitability by 660-nm laser irradiation in mouse neocortex
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660 nm 激光照射对小鼠新皮质神经元兴奋性的层特异性调节
DOI：
10.1007/s10103-013-1484-1
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
Kawai H
中科院分区：
文献类型：
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作者：
Kumazaki K;Mieda T;Kogure S;Kawai H
已有报道激光照射（LLI）可以调节前脑神经元的活动，但很少有人知道在红色波长范围内的LLI是否以及如何影响神经元的兴奋性。在这里，我们研究了在660 nm的连续二极管激光的内在膜特性和兴奋性的假定锥体神经元在丘脑皮质输入层（第3/4层）和在第5层的小鼠初级听觉皮层使用全细胞膜片钳记录技术。在第3/4层神经元，660-nm激光照射（LLI-660）在20 mW的5分钟逐渐增加静息膜电位，照射后达到一个平台。同时，LLI-660缩短了第一动作电位（spikes）的起始潜伏期，但不改变棘波阈值或峰振幅，但增加了初始爆发性棘波双峰的棘波间期及其峰振幅比。在第5层神经元中没有观察到这些变化。相反，在20 mW下，LLI-660在照射开始的1分钟内迅速降低尖峰宽度~ 5%。这种减少的幅度在5或10分钟照射期间没有变化，并且在关闭LLI后迅速恢复到至少基线水平。将激光功率降低到10 mW，在较小程度上降低了尖峰宽度，表明这种现象依赖于激光功率。这些数据表明，LLI-660可能通过影响不同的电压门控离子通道，以层依赖性方式调节皮层神经元中神经元兴奋性的不同方面。
It has been reported that laser light irradiation (LLI) could regulate neuronal activities in the forebrain, but little is known if and how LLI in the red wavelength range affects neuronal excitability. Here, we investigated the effects of a continuous diode laser at 660 nm on intrinsic membrane properties and excitability of presumed pyramidal neurons in the thalamocortical input layer (layer 3/4) and in layer 5 of mouse primary auditory cortex using the whole-cell patch-clamp recording technique. In layer 3/4 neurons, 660-nm laser irradiation (LLI-660) at 20 mW for 5 min gradually increased resting membrane potentials, which reached a plateau after irradiation. Concomitantly, LLI-660 decreased onset latency of first action potentials (spikes) without changing spike threshold or peak amplitude, but increased inter-spike interval of initial bursting spike doublets and their peak amplitude ratio. None of these changes was observed in layer 5 neurons. Instead, LLI-660 at 20 mW rapidly reduced spike width ~5 % within 1 min of irradiation onset. The magnitude of this reduction did not change during 5 or 10 min irradiation, and returned quickly to at least baseline levels after turning the LLI off. Decreasing laser power to 10 mW reduced spike width to a lesser extent, suggesting laser power dependence of this phenomenon. These data suggest that LLI-660 regulates different aspects of neuronal excitability in cortical neurons in a layer-dependent manner possibly by affecting different voltage-gated ion channels.