Chronic lentiviral expression of inwardly rectifying K+ channels (Kir2.1) reduces neuronal activity and downregulates voltage-gated potassium currents in hippocampus
Chronic lentiviral expression of inwardly rectifying K+ channels (Kir2.1) reduces neuronal activity and downregulates voltage-gated potassium currents in hippocampus
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DOI：
10.1016/j.neuroscience.2008.07.038
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发表时间：
2008-10-02
期刊：
影响因子：
3.3
通讯作者：
Matsuda, H.
中科院分区：
文献类型：
--
作者：
Okada, M.;Matsuda, H.
强内向整流性K+(Kir2)通道在大鼠脑内表达，最近被用作降低神经元活性的工具。但对Kir2通道的作用以及活性降低对神经元内在兴奋性的慢性影响知之甚少。在此，我们构建了共表达Kir2.1和GFP(LvKir2.1)的慢病毒载体，并将其感染海马片培养物。LvKir2.1感染的CA1神经元在15d以上表现出明显的内向整流钾电流。静息膜电位比未感染或单独感染GFP慢病毒载体的膜电位负值约10 mV。LvKir2.1的感染降低了电流刺激引起的电压变化，降低了mEPSP的波幅，具有分流作用。LvKir2.1感染显著减少了CA1神经元去极化电流引起的放电。放电的减少归因于超极化电位，而不是分流效应。这些减少仅限于适度的电流注入，这表明过度表达的Kir2.1起到了噪声过滤器的作用。此外，Kir2.1的慢性过表达以一种平衡的方式下调了延迟整流钾电流的表达，表明该病毒载体在研究活动依赖的神经元发育方面是有用的。(C)2008年IBRO。爱思唯尔有限公司出版。保留所有权利。
Strongly inwardly rectifying K+ (Kir2) channels are endogenously expressed in rat brains and have recently been used as a tool to reduce the neuronal activity. But little is known about the role of Kir2 channels and the chronic effect of the reduced activity on the intrinsic excitability of neurons. Here we constructed a lentiviral vector that coexpressed Kir2.1 and GFP (LvKir2.1) and infected the vector to the hippocampal slice cultures. The LvKir2.1-infected CA1 neurons showed clear inwardly rectifying K+ currents for more than 15 days. The resting membrane potential was more negative by approximately 10 mV than those uninfected or infected with the lentiviral vector expressing GFP alone. The infection of LvKir2.1 reduced the voltage change in response to current injections and the amplitude of mEPSPs with a shunting effect. The LvKir2.1 infection significantly reduced the firings evoked by depolarizing currents in the CA1 neurons. The reduction of the firing was attributed to the hyperpolarized potential rather than to the shunting effect. These reductions were limited to modest current injections, suggesting that the overexpressed Kir2.1 plays the role of a noise-filter. Moreover, the chronic overexpression of Kir2.1 downregulated the expression of the delayed rectifier potassium current in a homeostatic manner, indicating a usefulness of this viral vector to study the activity-dependent neuronal development. (C) 2008 IBRO. Published by Elsevier Ltd. All rights reserved.