FIGURE 1.

Effects of chronic caffeine consumption on wild-type mice and A_2AR knockout mice in behavioral experiments. (A,B) Behavior of the four groups of mice in the open-field test. Caffeine induced anxiogenic behavior with decreased time in the center (A) and distance in the center (B) in wild-type mice. (C,D) Behavior of the four groups of mice in the Elevated Plus Maze (EPM) test. Caffeine decreased the percentage of open-arm entries (C) and the percentage of time spent in the open arms (D) in wild-type mice. (E) Behavior of the four groups of mice in the Novel Object Recognition (NOR) test. The time spent exploring a novel object is shown as the ratio of the total time spent exploring both objects in the testing trial. (F) Behavior of the four groups of mice in the Y-maze test. The time spent in the novel arm is shown during the retrieval phase. Data are presented as the mean ± SEM, n = 7 mice per group; *p < .05, two-way ANOVA, Bonferroni post hoc t-test.