Fig. 6.

Inhibition of BD-CsA and NBD-CsA transport by tariquidar. Histogram traces showing the steady-state efflux of BD-CsA (A) and NBD-CsA (B) by P-gp (blue traces), and inhibition of efflux by tariquidar (200 nM) (gray traces). The fluorescence intensity was compared with the cells not expressing P-gp (untransduced, red traces). (C) Graph plot showing the tariquidar concentration-dependent inhibition of efflux by P-gp and comparison of BD-CsA (blue circles) with NBD-CsA (red squares). The IC₅₀ for tariquidar was 21.6 ± 0.6 nM for BD-CsA and 25.8 ± 1.5 nM for NBD-CsA. The experiment was repeated three times, and error bars show S.D.