Haas Brigitte, Schipke Carola G, Peters Oliver, Söhl Goran, Willecke Klaus, Kettenmann Helmut
Cellular Neuroscience, Max-Delbrück-Center for Molecular Medicine, and Institute of Genetics, Division of Molecular Genetics, University of Bonn, 53117 Bonn, Germany Eschenallee 3, 14050 Berlin, Germany.
Cereb Cortex. 2006 Feb;16(2):237-46. doi: 10.1093/cercor/bhi101. Epub 2005 Jun 1.
In the corpus callosum, astrocytic calcium waves propagate via a mechanism involving ATP-release but not gap junctional coupling. In the present study, we report for the neocortex that calcium wave propagation depends on functional astrocytic gap junctions but is still accompanied by ATP-release. In acute slices obtained from the neocortex of mice deficient for astrocytic expression of connexin43, the calcium wave did not propagate. In contrast, in the corpus callosum and hippocampus of these mice, the wave propagated as in control animals. In addition to calcium wave propagation in astrocytes, ATP-release was recorded as a calcium signal from 'sniffer cells', a cell line expressing high-affinity purinergic receptors placed on the surface of the slice. The astrocyte calcium wave in the neocortex was accompanied by calcium signals in the 'sniffer cell' population. In the connexin43-deficient mice we recorded calcium signals from sniffer cells also in the absence of an astrocytic calcium wave. Our findings indicate that astrocytes propagate calcium signals by two separate mechanisms depending on the brain region and that ATP release can propagate within the neocortex independent from calcium waves.
在胼胝体中，星形胶质细胞钙波通过一种涉及ATP释放而非缝隙连接耦合的机制进行传播。在本研究中，我们报告在新皮层中，钙波传播依赖于功能性星形胶质细胞缝隙连接，但仍伴有ATP释放。在从缺乏星形胶质细胞表达连接蛋白43的小鼠新皮层获得的急性切片中，钙波无法传播。相比之下，在这些小鼠的胼胝体和海马体中，钙波的传播与对照动物相同。除了星形胶质细胞中的钙波传播外，还记录到ATP释放作为来自“嗅探细胞”的钙信号，“嗅探细胞”是一种表达高亲和力嘌呤能受体的细胞系，放置在切片表面。新皮层中的星形胶质细胞钙波伴随着“嗅探细胞”群体中的钙信号。在连接蛋白43缺陷小鼠中，我们在没有星形胶质细胞钙波的情况下也记录到了来自嗅探细胞的钙信号。我们的研究结果表明，星形胶质细胞根据脑区通过两种不同的机制传播钙信号，并且ATP释放可以在新皮层内独立于钙波进行传播。
