The K+ channel, Kv2.1, is apposed to astrocytic processes and is associated with inhibitory postsynaptic membranes in hippocampal and cortical principal neurons and inhibitory interneurons
The K+ channel, Kv2.1, is apposed to astrocytic processes and is associated with inhibitory postsynaptic membranes in hippocampal and cortical principal neurons and inhibitory interneurons
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DOI：
10.1016/s0306-4522(97)00519-8
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发表时间：
1998-05-01
期刊：
影响因子：
3.3
通讯作者：
McBain, CJ
中科院分区：
文献类型：
--
作者：
Du, J;Tao-Cheng, JH;McBain, CJ
多种电压门控离子通道在主细胞树突上表达，并被认为在树突兴奋性的调节中起关键作用。以往的研究表明，在光镜水平上的K+通道亚基Kv2.1的表达是极化的细胞索马和树突的主要神经元在整个中枢神经系统。在这里，使用双重免疫染色，我们现在表明，Kv2.1蛋白在大多数皮质和海马小清蛋白，钙结合蛋白和生长抑素抑制性中间神经元类似地表达。在电子显微镜水平Kv2.1免疫反应主要观察到的质膜上的胞体和近端树突的主要神经元和抑制性interneurons的表达是低的较小的树突状分支，和缺席的轴突和突触前末梢。Kv2.1亚基表达高度集中在细胞表面膜上，直接面对星形胶质细胞的过程。Kv2.1表达也集中在特定的细胞质隔室和表面下的cispellar质膜面向星形胶质细胞。此外，Kv2.1亚基的免疫反应性与突触后密度的抑制性对称突触的一部分，而在不对称synapses的表达是罕见的。这些数据表明，由Kv2.1亚基形成的通道是唯一的定位在索马和主要树突的锥体细胞和抑制性interneurons在网站紧邻星形胶质细胞的进程。这种与星形胶质细胞的紧密贴壁将确保快速清除并限制释放到细胞外间隙中的K+的影响。这种表达模式表明Kv2.1形成的通道准备在神经元树突兴奋性的调节中发挥作用。(C)1998年IBRO。出版社：Elsevier Science Ltd
A variety of voltage-gated ion channels are expressed on principal cell dendrites and have been proposed to play a pivotal role in the regulation of dendritic excitability. Previous studies at the light microscopic level demonstrated that the K+ channel subunit Kv2.1 expression was polarized to the cell soma and dendrites of principal neurons throughout the central nervous system. Here, using double immunostaining we now show that Kv2.1 protein is similarly expressed in the majority of cortical and hippocampal parvalbumin, calbindin and somatostatin-containing inhibitory interneurons. At the electron microscopic level Kv2.1 immunoreactivity was primarily observed on the plasma membrane of the somata and proximal dendrites of both principal neurons and inhibitory interneurons; expression was low on smaller dendritic branches, and absent on axons and presynaptic terminals. Kv2.1 subunit expression was highly concentrated on the cell surface membrane immediately facing astrocytic processes. Kv2.1 expression was also concentrated in specific cytoplasmic compartments and on the subsurface cisterns underlying the plasma membrane facing astrocytes. In addition, Kv2.1 subunit immunoreactivity was associated with postsynaptic densities of a fraction of inhibitory symmetric synapses; while expression at asymmetric synapses was rare.These data demonstrate that channels formed by Kv2.1 subunits are uniquely positioned on the soma and principal dendrites of both pyramidal cells and inhibitory interneurons at sites immediately adjacent to astrocytic processes. This close apposition to astrocytes will ensure a rapid removal and limit the influence of K+ released into the extracellular space. This expression pattern suggests that channels formed by Kv2.1 are poised to provide a role in the regulation of neuronal dendritic excitability. (C) 1998 IBRO. Published by Elsevier Science Ltd.