Monitoring Astrocytic Ca2+ Activity in Freely Behaving Mice

• Main Authors: Han Qin, Wenjing He, Chuanyan Yang, Jin Li, Tingliang Jian, Shanshan Liang, Tunan Chen, Hua Feng, Xiaowei Chen, Xiang Liao, Kuan Zhang
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2020-12-01
• Series: Frontiers in Cellular Neuroscience
• Subjects: optic fiber; astrocytes; Ca2+ signals; genetically encoded Ca2+ indicators; freely behaving mice; cortex
• Online Access: https://www.frontiersin.org/articles/10.3389/fncel.2020.603095/full

Monitoring astrocytic Ca2+ activity is essential to understand the physiological and pathological roles of astrocytes in the brain. However, previous commonly used methods for studying astrocytic Ca2+ activities can be applied in only anesthetized or head-fixed animals, which significantly affects in vivo astrocytic Ca2+ dynamics. In the current study, we combined optic fiber recordings with genetically encoded Ca2+ indicators (GECIs) to monitor astrocytic activity in freely behaving mice. This approach enabled selective and reliable measurement of astrocytic Ca2+ activity, which was verified by the astrocyte-specific labeling of GECIs and few movement artifacts. Additionally, astrocytic Ca2+ activities induced by locomotion or footshock were stably recorded in the cortices and hippocampi of freely behaving mice. Furthermore, this method allowed for the longitudinal study of astrocytic activities over several weeks. This work provides a powerful approach to record astrocytic activity selectively, stably, and chronically in freely behaving mice.