Freshly dissociated mature hippocampal astrocytes exhibit passive membrane conductance and low membrane resistance similarly to syncytial coupled astrocytes
Freshly dissociated mature hippocampal astrocytes exhibit passive membrane conductance and low membrane resistance similarly to syncytial coupled astrocytes
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DOI：
10.1152/jn.00206.2015
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发表时间：
2015-06-01
影响因子：
2.5
通讯作者：
Zhou, Min
中科院分区：
文献类型：
--
作者：
Du, Yixing;Ma, Baofeng;Zhou, Min
成熟的星形胶质细胞在原位表现出线性的电流-电压K+膜电导（被动电导）和极低的膜电阻（Rm）。这些电生理特征的组合建立了一个高度负性和稳定的膜电位，这是基本功能所必需的，如K+空间缓冲和神经递质摄取。然而，星形胶质细胞在原位广泛偶联。它仍然有待确定是否观察到的被动行为和低R-m可归因于膜离子通道的内在特性或功能成熟的星形胶质细胞中的间隙连接耦合。在本研究中，新鲜分离的海马组织被用作一种新的模型来研究这个基本问题在年轻的成年动物。形态完整的单个星形胶质细胞可以可靠地从出生后21天及以上的动物中分离出来。在该动物年龄，解离的单个星形胶质细胞表现出与原位星形胶质细胞相似的被动电导和静息膜电位。为了精确地测量来自单个星形胶质细胞的R-m，进行了双膜片单星形胶质细胞记录。我们发现，解离的单个星形胶质细胞表现出低的R-m类似于合胞体耦合星形胶质细胞。在功能上，高K+电导的对称表达使细胞内K+浓度响应于改变K+驱动力而快速变化。总之，我们表明，新鲜分离的组织制备是一个非常有用的模型，用于研究星形胶质细胞中离子通道，受体和转运蛋白的功能表达和调控，被动行为和低R-m是成熟星形胶质细胞的固有特性。
Mature astrocytes exhibit a linear current-to-voltage K+ membrane conductance (passive conductance) and an extremely low membrane resistance (R-m) in situ. The combination of these electrophysiological characteristics establishes a highly negative and stable membrane potential that is essential for basic functions, such as K+ spatial buffering and neurotransmitter uptake. However, astrocytes are coupled extensively in situ. It remains to be determined whether the observed passive behavior and low R-m are attributable to the intrinsic properties of membrane ion channels or to gap junction coupling in functionally mature astrocytes. In the present study, freshly dissociated hippocampal tissues were used as a new model to examine this basic question in young adult animals. The morphologically intact single astrocytes could be reliably dissociated from animals postnatal day 21 and older. At this animal age, dissociated single astrocytes exhibit passive conductance and resting membrane potential similar to those exhibited by astrocytes in situ. To precisely measure the R-m from single astrocytes, dual-patch single-astrocyte recording was performed. We show that dissociated single astrocytes exhibit a low R-m similarly to syncytial coupled astrocytes. Functionally, the symmetric expression of high-K+ conductance enabled rapid change in the intracellular K+ concentrations in response to changing K+ drive force. Altogether, we demonstrate that freshly dissociated tissue preparation is a highly useful model for study of the functional expression and regulation of ion channels, receptors, and transporters in astrocytes and that passive behavior and low R-m are the intrinsic properties of mature astrocytes.