Figure 2.

Effects of UCPH-101 and UCPH-102 on whole-cell currents of EAAT1, EAAT4, and EAAT5. A, C, E, Representative whole-cell currents from tsA201 cells expressing EAAT1 (A), EAAT4 (C), and EAAT5 (E) in the absence (top) and presence (bottom) of 10 μm UCPH-101. The compound was added to bath solution containing 140 mm NaNO₃ and 0.5 mm Glu, and cells were dialyzed with 115 mm KNO₃. Dotted lines represent 0 nA. B, D, F, Current–voltage relationship of EAAT1 (n = 14) (B), EAAT4 (n = 16) (D), and EAAT5 (n = 11) (F) in the absence () or presence (●) of 10 μm UCPH-101. Untransfected tsA201 cells perfused with external solution containing 0.5 mm Glu were used as control (○) (n = 9). G, Application of different concentrations of UCPH-101 or UCPH-102 to cells expressing EAAT1 at a voltage step of −185 mV (solutions as in A–F). Data were normalized to the current in absence of compounds. Fitting concentration dependences of EAAT1 steady-state currents (arrow in Fig. 2A) with a Hill equation provided dissociation constants of 0.34 ± 0.03 μm (Hill coefficient = 1.3 ± 0.13, n ≥ 9) for UCPH-101 and 0.17 ± 0.02 μm (Hill coefficient = 0.97 ± 0.11, n ≥ 7) for UCPH-102. H, Effect of 10 μm UCPH-101 or 10 μm UCPH-102 on anion currents of EAAT1, EAAT4, and EAAT5 at a voltage step of −185 mV (solutions as in A–F). To determine the inhibitory effect of UCPH-101 (black bar) and UCPH-102 (gray bar) on EAAT-mediated anion currents, we divided steady-state currents in the presence of UCPH-101/UCPH-102 by currents in the absence of compounds. Data are given as mean ± SE.