Figure 7.

Blockade of Glt1 in C57BL/6N astrocytes leads to enhanced astrocyte iGluSnFR signals and enhanced astrocyte Ca²⁺ signals evoked by EFS of cortical axons. A, Individual traces (gray) and averages (black) for GCaMP3 imaging showing increased spontaneous Ca²⁺ signals in astrocytes from C57BL/6N mice in the presence of TBOA (1 μm). Bar graph to the right shows average data for the peak area before and during applications of TBOA. B, As in A, but for iGluSnFR imaging showing elevated basal glutamate levels in the presence of TBOA. C, Individual traces (gray) and averages (black) for 4 EFS-evoked iGluSnFR signals in the absence of TBOA as well as in its presence. D, E, Average data for peak amplitude and decay time for traces such as those shown in C. F, Individual traces (gray) and averages (black) for 4 EFS-evoked GCaMP3 Ca²⁺ signals in the presence of TBOA or TBOA/TTX measured in somata of astrocytes in C57BL/6N mice. Tilted arrows indicate the expected time for the EFS-evoked Ca²⁺ signals. G, Summary bar graph for experiments such as those shown in F in the presence of different drugs. H, I, As in F and G, but for measurements in branches instead of somata. J, Representative confocal images of a GCaMP3-expressing astrocyte taken before, during, and after 4 EFS in the presence of TBOA. Bar graph to the right shows the area of the astrocyte territory and the area of the 4 EFS-evoked Ca²⁺ signals. In some cases, the error bars signifying SEM are smaller than the symbols used.