Figure 4.

A, B, Total time spent in wakefulness and in NREM and REM sleep for 9 h after modafinil administration (A) and pretreatment with D₁R antagonist before modafinil (B) to D₂R KO mice. On the experimental day, modafinil was given at 10:00 A.M., and pretreatment with the D₁R antagonist was given at 9:30 A.M. The vehicle was used on the baseline day. Each value is presented as the mean ± SEM (n = 6–8). *p < 0.05, **p < 0.01, significantly different from the control, as assessed by one-way ANOVA followed by the PLSD test.