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Fig. 5 | Fluids and Barriers of the CNS

Fig. 5

From: Similarities and differences in the localization, trafficking, and function of P-glycoprotein in MDR1-EGFP-transduced rat versus human brain capillary endothelial cell lines

Fig. 5

Characteristics of primary cultured rat brain capillary endothelial cells (rBCECs), which were prepared for comparison with the RBE4 rat BCEC line. Pgp expression of these cells is shown in Fig. 3. Average TEER of rBCEC monolayers (A), shown as mean ± SEM of four replicates. Rhodamine 123 (Rho123) uptake assay in the absence (− TQ) or presence of the Pgp inhibitor tariquidar (0.5 µM, + TQ) (B). Data are shown as mean ± SEM of six replicates. Student’s t test revealed a significant effect of tariquidar as indicated by an asterisk (P < 0.0001). Directional Pgp transport assay (CETA), using Rho123 as a Pgp substrate (CF). Data are shown as mean ± SEM of four replicates. Data were analyzed by two-way ANOVA followed by Bonferroni post hoc tests. Rho123 is transported from the basolateral to the apical chamber, leading to significant concentration differences between the two chambers (**P < 0.01). The increase in Rho123 levels in the basolateral chamber at 240 min could indicate redistribution of this Pgp substrate from the apical to the basolateral chamber by passive diffusion. The average TEER of the cell monolayers used in this assay was 163 Ω cm2. For comparison with vectorial drug transport in rBCECs (C), Rho123 transport in the CETA is shown for MDR1 transfected LLC cells (D), MDR1-EGFP transduced RBE4 cells (E), and MDR1-EGFP transduced hCMEC/D3 cells (F). Data are shown as mean ± SEM of three replicates; data were analyzed by two-way ANOVA followed by Bonferroni post hoc tests; significant differences between drug levels in the apical vs. basolateral chambers are indicated by asterisks (*P < 0.05; **P < 0.01)

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