Caffeine potentiates glutamate-induced Ca2+ signals in YAC128 and WT MSN cultures. Representative 340/380 nm Fura-2 ratio traces are shown for YAC128 (red) and WT (green) after application of 2.5 μM glutamate (A), 2.5 mM caffeine (B), and 2.5 μM glutamate + 2.5 mM caffeine simultaneously (C). The average differences between the peak ratio and base line ratio for each treatment was calculated and shown as mean ± SE, n = number of cells (D). *p < 0.05 compared to corresponding genotype treated with 2.5 μM glutamate only, #p < 0.05 comparing YAC128 to WT, and ns = not significant using one-way ANOVA with Tukey's post test. WT, wild type; YAC, YAC128; glu, glutamate.