Schipke Carola G, Heidemann Antje, Skupin Alexander, Peters Oliver, Falcke Martin, Kettenmann Helmut
Charité University Medicine Berlin, Department of Psychiatry and Psychotherapy, CBF, Eschenallee 3, 14050 Berlin, Germany.
Cell Calcium. 2008 Mar;43(3):285-95. doi: 10.1016/j.ceca.2007.06.002. Epub 2007 Aug 14.
Transient spontaneous increases in the intracellular Ca2+ concentration have been frequently observed in astrocytes in cell culture and in acutely isolated slices from several brain regions. Recent in vivo experiments, however, reported only a low frequency of spontaneous Ca2+ events in astrocytes. Since the ex vivo experiments were usually performed at temperatures lower than physiological body temperature, we addressed the question whether temperature could influence the spontaneous Ca2+ activity in astrocytes. Indeed, comparing the frequency and spike width of spontaneous Ca2+ transients in astrocytes at temperatures between 20 and 37 degrees C in culture as well as in acute cortical slices from mouse brain, revealed that spontaneous Ca2+ responses occurred frequently at low temperature and became less frequent at higher temperature. Moreover, the single Ca2+ events had a longer duration at low temperature. We found that nitric oxide (NO) mimicked the increase in spontaneous Ca2+ activity and that an NO-synthase inhibitor attenuated the effect of lowering the temperature. Thus, temperature and NO are major determinants of spontaneous astrocytic Ca2+ signalling.
在细胞培养的星形胶质细胞以及从多个脑区急性分离的切片中，经常观察到细胞内Ca2+浓度的短暂自发升高。然而，最近的体内实验报告显示，星形胶质细胞中自发Ca2+事件的频率很低。由于离体实验通常在低于生理体温的温度下进行，我们探讨了温度是否会影响星形胶质细胞中自发Ca2+活性的问题。确实，比较培养物中以及小鼠脑急性皮质切片中20至37摄氏度之间温度下星形胶质细胞中自发Ca2+瞬变的频率和尖峰宽度，发现自发Ca2+反应在低温下频繁发生，而在较高温度下则变得不那么频繁。此外，单个Ca2+事件在低温下持续时间更长。我们发现一氧化氮（NO）模拟了自发Ca2+活性的增加，并且一种NO合酶抑制剂减弱了降低温度的效果。因此，温度和NO是星形胶质细胞自发Ca2+信号传导的主要决定因素。
