English: This movie is a two-photon z-stack recording (70 µm, 2 µm, 0.5 min−1) of a SR101-staining experiment with 3 different SR101-concentrations. After recording one z-stack without SR101, 0.1 µM SR101 was bath-applied, 20 minutes later the SR101-concentration was increased to 1 µM for 20 minutes. Finally, 10 µM SR101 was applied for 20 minutes before the recording was stopped. The white spots identify EGFP-labeled astrocytes that were selected for analysis of fluorescence intensities (Figure 5). The blue spot marks the position where fluorescence background within the slice was recorded, while the purple spot was located above the slice to record fluorescence changes of the bath solution (Scale bar 40 µm).