Figure 6.

P-gp-mediated transport in isolated rat brain capillaries. P-gp transport activity was determined using isolated rat brain capillaries as described in Methods. Representative images of capillaries preincubated with (A) DMSO, (B) 5 μM PSC833, (C) 2.5 μM QT, or (D) 2.5 μM QT₂C₂Me₂ (8) followed by 60 min incubation with 2 μM NBD-CsA. Capillary fluorescence was visualized with a Zeiss 510 NLO confocal scanning microscope and quantitated from images using ImageJ software. (E, F) Capillaries were preincubated with the indicated concentrations of (D) QT and (E) QT₂C₂Me₂ (8) followed by 60 min incubation with 2 μM NBD-CsA. Shown are mean ± SEM for 5–12 capillaries. Statistical comparisons: one-way ANOVA, ***P < 0.001.