Figure 7. Dose–response curves for whole-cell GTCs. A, B, Sample traces of GTCs evoked by photolytic uncaging in control solution (CTRL, A) and Ba2+ (100 μm, B). Traces from HD mice are drawn with thinner lines. The current maxima obtained in WT versus HD with 3 mm Rubi-glutamate are indicated by horizontal lines. Experiments at Vh of −80 mV in MK801 (1 μm), DNQX (10 μm), LY341495 (20 μm), and CBX (100 μm). C, D, Dose–response curves for GTCs at Vh of −100 mV. The lines represent exponential fitting curves. The stars in B and C refer to the comparison of the mean values obtained in WT and HD at the given concentration. A significant difference between WT and HD is only seen at higher Rubi-glutamate concentration. The EC50 (calculated from the fitting curves in CTRL and Fig. 7). Dose–response curves for whole-cell GTCs. A, B, Sample traces of GTCs evoked by photolytic uncaging in control solution (CTRL, A) and Ba2+ (100 μm, B). Traces from HD mice are drawn with thinner lines. The current maxima obtained in WT versus HD with 3 mm Rubi-glutamate are indicated by horizontal lines. Experiments at Vh of −80 mV in MK801 (1 μm), DNQX (10 μm), LY341495 (20 μm), and CBX (100 μm). C, D, Dose–response curves for GTCs at Vh of −100 mV. The lines represent exponential fitting curves. The stars in B and C refer to the comparison of the mean values obtained in WT and HD at the given concentration. A significant difference between WT and HD is only seen at higher Rubi-glutamate concentration. The EC50 (calculated from the fitting curves in CTRL and Ba2+) did not differ, but there was a significant HD-related deficit in the calculated response maximum. Statistics: two-way ordinary ANOVA. C, Genotype, F(1,93) = 6, p = 0.02; [Rubi-glutamate], F(3,93) = 147.9, p < 0.0001; interaction, p = 0.019. The genotype-related difference within groups (same [Rubi-glutamate]) was tested with unpaired t tests. Comparison of fit parameters with extra sum-of-squares F test: maximum, F(1,97) = 6.37, p = 0.013; EC50, F(1,97) = 0.59, p = 0.45. D, Genotype, F(1,69) = 19.65, p < 0.001; [Rubi-glutamate], F(3,69) = 194.4, p < 0.0001; interaction, p < 0.001. The genotype-related difference within groups (same [Rubi-glutamate]) was tested with unpaired t tests. Comparison of fit parameters with extra sum-of-squares F test: maximum, F(1,73) = 6.1, p = 0.016; EC50, F(1,73) = 0.12, p = 0.73. The total number of tested astrocytes is given in parentheses above and below the fitting curves. Note different scaling of y-axes in C and D. E, F, Maximal GTC values calculated for different levels of Vh. The mean values of GTC (maximum) in WT and HD are different in CTRL (D) and Ba2+ (E). Statistics: two-way ordinary ANOVA. (E, genotype) - F (1, 2079) = 63.9, p < 0.001. (E, Vh) - F (20, 2079) = 56.4, p < 0.001. F, Genotype, F(1,1575) = 84.2, p < 0.001; Vh, F(20,1575) = 63.8, p < 0.001; interaction, NS. Differences between groups, F test. The difference between WT and HD does not depend on Vh (no interaction).