Figure 6.

CASPR1 affects the glutamate efflux through brain endothelial cells. A, schematic representation of in vitro glutamate efflux assay with HBMECs. The HBMECs were cultured on the Transwell insert placed on a 24-well plate for 5 days until formation of endothelial barrier with tight junctions. Then the glutamate (200 μm) was added to the lower chamber of the Transwell, and the glutamate in the upper chamber of Transwell was measured at the indicated time points. B and C, the HBMECs with CASPR1 knockdown were cultured on the Transwell insert, and the in vitro glutamate efflux assay was performed, with nonsilencing shRNA as control. The glutamate concentrations in the upper chamber of the Transwell were measured at the indicated time points (B). The glutamate concentrations in the lower chamber of Transwell were measured, and the ratio of glutamate concentrations in the upper chamber divided by glutamate concentrations in the lower chamber was calculated (C). Data are mean ± S.D. (error bars) from three independent experiments. *, p < 0.05. **, p < 0.01 (one-way ANOVA, Student's t test).