Light/dark box experiments verified altered anxiety and exploratory behavior.

<p>Comparing the running distance of the animals in the open field revealed no significant differences (A). However, the distance traveled by ABCB1-deficient mice (+64%) in the dark compartment (B) was significantly increased compared to the controls. Also, the time in the dark compartment (C) was significantly increased in ABCB1^0/0 mice (+78%) compared to controls. The mean number of transitions between the two compartments (D) was impaired in both ABCB1^0/0 (−59%) and ABCC1^0/0 (−49%) mice. Comparing the rearing frequency in both compartments revealed a significant decrease for ABCC1^0/0 (−67%) mice in the open field (E), while the frequency was increased in the dark compartment (F) for ABCB1^0/0 (+71%) mice. Error bar: SEM, *