Locally Synchronized Astrocytes
Locally Synchronized Astrocytes
复制标题
DOI：
10.1093/cercor/bhq256
复制
发表时间：
2011-08-01
期刊：
影响因子：
3.7
通讯作者：
Ikegaya, Yuji
中科院分区：
文献类型：
--
作者：
Sasaki, Takuya;Kuga, Nahoko;Ikegaya, Yuji
星形胶质细胞表现出自发的钙波动。这些活动还没有被大规模的录音记录下来，对它们的集体动力学知之甚少。小鼠海马和新皮层中数百个（多达2195个）星形胶质细胞的原位和体内钙成像显示，邻近的星形胶质细胞自发地表现出同步钙升高，并形成局部相关的细胞群（直径为81 +/- 45 μ m的2至5个星形胶质细胞的“簇”）。集群活动约占10%的星形胶质细胞钙事件，和44%的集群重复出现在我们的观察期为60分钟。星形胶质细胞集群出现通过代谢型谷氨酸受体激活，独立的神经元活动。当神经元树突附近出现簇时，神经元被去极化1.5 mV。这种去极化由非N-甲基-D-天冬氨酸（NMDA）谷氨酸受体通道介导，并通过多种星形胶质细胞的钙离子释放激活来复制。重要的是，单个星形胶质细胞的激活不能使神经元去极化，但容易在去极化神经元中引起NMDA依赖的慢内向电流。因此，这些新的整体动力学的星形胶质细胞，这不能被捕获的常规小规模成像技术，发挥不同的作用，在神经元的调制比单个星形胶质细胞的零星活动。
Astrocytes exhibit spontaneous calcium fluctuations. These activities have not been captured by large-scale recordings, and little is known about their collective dynamics. In situ and in vivo calcium imaging from hundreds (up to 2195) of astrocytes in the mouse hippocampus and neocortex revealed that neighboring astrocytes spontaneously exhibited synchronous calcium elevations and formed locally correlated cell groups ("clusters" of 2 to 5 astrocytes within a diameter of 81 +/- 45 mu m). Cluster activity accounted for approximately 10% of the astrocytic calcium events, and 44% of the clusters appeared repetitively during our observation period of 60 min. Astrocytic clusters emerged through metabotropic glutamate receptor activation, independently of neuronal activity. Neurons were depolarized by 1.5 mV when clusters appeared near their dendrites. This depolarization was mediated by non-N-methyl-D-aspartate (NMDA) glutamate receptor channels and was replicated by calcium uncaging activation of multiple astrocytes. Importantly, the activation of single astrocytes alone could not depolarize neurons but readily elicited NMDA-dependent slow inward currents in depolarized neurons. Thus, these novel ensemble dynamics of astrocytes, which cannot be captured by conventional small-scale imaging techniques, play a different role in neuronal modulation than does the sporadic activity of single astrocytes.