METH and CB increase BBB permeability and decrease TEER. (A-D) Permeability of sodium fluorescein (NaFl, 5 μM) or Evans Blue (EB, 5 μM) across the BBB in acute METH exposure (A-B) and chronic METH administration (15 mg/kg body weight) (C-D). (E) Trans-endothelial electrical resistance (TEER) of hBECs monolayers following treatment with various test compounds (n = 2). TEER was measured at 400 Hz in 10 min intervals for 12 hours. The treatments were started after stable resistance was reached for 1 hr. *Statistically significant (*p < 0.05, **p < 0.01 and ***p < 0.001) compared with controls.