ABCB1 and epilepsy: Although the physiological level of ABCB1 expression in astrocytes is low and the exact role of this basal expression is totally unknown, it is well reported that under pathophysiological conditions, such as epilepsy, ABCB1 expression is highly increased and specifically at the endfeet of reactive astrocytes, thus playing a major role in epileptic drug resistance (Sisodiya et al., 2002).