In Vivo Intracellular Recording Suggests That Gray Matter Astrocytes in Mature Cerebral Cortex and Hippocampus Are Electrophysiologically Homogeneous
In Vivo Intracellular Recording Suggests That Gray Matter Astrocytes in Mature Cerebral Cortex and Hippocampus Are Electrophysiologically Homogeneous
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DOI：
10.1523/jneurosci.5065-09.2010
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发表时间：
2010-02-24
影响因子：
5.3
通讯作者：
Hirase, Hajime
中科院分区：
文献类型：
--
作者：
Mishima, Tsuneko;Hirase, Hajime
先前的解剖和体外电生理学研究表明，星形胶质细胞在生理、形态和生化内容上是异质的。然而，这种多样性适用于体内条件的程度在很大程度上是未知的。为了描述和分类完整大脑中大脑皮层和海马星形胶质细胞的生理和形态学特性，我们对麻醉的成熟大鼠进行了单个星形胶质细胞的体内细胞内记录。根据胶质原纤维酸性蛋白（GFAP）免疫反应性和细胞体位置对星形胶质细胞进行分类。我们分析了形态计量学指标，如占据体积和极性，以及生理特征，如平均膜电位。这些测量没有显示出明显的亚群分离，这表明在成熟的动物中，皮层和海马中的灰质星形胶质细胞是由一个均匀的群体组成的。在自发网络活动的情况下，皮层和海马星形胶质细胞的膜电位在几毫伏范围内波动。星形胶质细胞的这些膜电位波动表现出明显的可变性，这取决于局部场电位状态和细胞体位置。我们将膜电位波动的可变性归因于神经元活动引起的局部钾浓度变化。
Previous anatomical and in vitro electrophysiology studies suggest that astrocytes are heterogeneous in physiology, morphology, and biochemical content. However, the extent to which this diversity applies to in vivo conditions is largely unknown. To characterize and classify the physiological and morphological properties of cerebral cortical and hippocampal astrocytes in the intact brain, we performed in vivo intracellular recordings from single astrocytes using anesthetized mature rats. Astrocytes were classified based on their glial fibrillary acidic protein (GFAP) immunoreactivity and cell body locations. We analyzed morphometric measures such as the occupied volume and polarity, as well as physiological characteristics such as the mean membrane potential. These measurements did not show obvious segregation into subpopulations, suggesting that gray matter astrocytes in the cortex and hippocampus are composed of a homogeneous population in mature animals. The membrane potential of astrocytes in both cortex and hippocampus fluctuated within a few millivolts in the presence of spontaneous network activity. These membrane potential fluctuations of an astrocyte showed a significant variability that depended on the local field potential state and cell body location. We attribute the variability of the membrane potential fluctuations to local potassium concentration changes due to neuronal activity.