Huazhong University of Science and Technology, Wuhan National Laboratory for Optoelectronics, Britton Chance Center for Biomedical Photonics, Wuhan 430074, China.
J Biomed Opt. 2010 May-Jun;15(3):035001. doi: 10.1117/1.3454390.
Astrocytes have been identified to actively contribute to brain functions through Ca(2+) signaling, serving as a bridge to communicate with neurons and other brain cells. However, conventional stimulation techniques are hard to apply to delicate investigations on astrocytes. Our group previously reported photostimulation with a femtosecond laser to evoke astrocytic calcium (Ca(2+)) waves, providing a noninvasive and efficient approach with highly precise targeting. In this work, detailed characteristics of astrocytic Ca(2+) signaling induced by photostimulation are presented. In a purified astrocytic culture, after the illumination of a femtosecond laser onto one cell, a Ca(2+) wave throughout the network with reduced speed is induced, and intracellular Ca(2+) oscillations are observed. The intercellular propagation is pharmacologically confirmed to be mainly mediated by ATP through P(2)Y receptors. Different patterns of Ca(2+) elevations with increased amplitude in the stimulated astrocyte are discovered by varying the femtosecond laser power, which is correspondingly followed by broader intercellular waves. These indicate that the strength of photogenerated Ca(2+) signaling in astrocytes has a positive relationship with the stimulating laser power. Therefore, distinct Ca(2+) signaling is feasibly available for specific studies on astrocytes by employing precisely controlled photostimulation.
星形胶质细胞通过 Ca(2+)信号积极参与脑功能，充当与神经元和其他脑细胞进行通信的桥梁。然而，传统的刺激技术很难应用于对星形胶质细胞的精细研究。我们小组之前曾报道过使用飞秒激光进行光刺激以引发星形胶质细胞钙 (Ca(2+)) 波，这提供了一种非侵入性且高效的方法，具有高度精确的靶向性。在这项工作中，展示了光刺激诱导的星形胶质细胞 Ca(2+)信号的详细特征。在纯化的星形胶质细胞培养物中，用飞秒激光照射一个细胞后，会诱导整个网络中速度降低的 Ca(2+)波，并观察到细胞内 Ca(2+)振荡。通过 P(2)Y 受体的药理学确认，细胞间的传播主要由 ATP 介导。通过改变飞秒激光功率，发现刺激星形胶质细胞中 Ca(2+)升高的幅度增加且具有不同模式，这相应地伴随着更广泛的细胞间波。这表明光生成的 Ca(2+)信号在星形胶质细胞中的强度与刺激激光功率呈正相关。因此，通过精确控制的光刺激，可以为星形胶质细胞的特定研究提供不同的 Ca(2+)信号。
