Glutamate-induced currents as a function of glutamate concentration in EAAT3/EAAT4-expressing <i>Xenopus</i> oocytes wihout or with Klotho coexpression.

<p>A, C: Means ± SEM of glutamate-induced current (I_glu) as a function of glutamate concentration in <i>Xenopus</i> oocytes injected with cRNA encoding EAAT3 (A, n = 9) or EAAT4 (C, n = 6) without (open circles) or with (closed circles) additional coexpression of Klotho.*,**(p<0.05, p<0.01) indicate statistically significant difference from <i>Xenopus</i> oocytes injected with cRNA encoding EAAT3 (A) or EAAT4 (C) alone (two-tailed unpaired <i>t</i>-test). <b>B, D:</b> Means ± SEM of glutamate induced current (I_glu) normalized to I_glu at 5 mM glutamate as a function of glutamate concentration in <i>Xenopus</i> oocytes injected with cRNA encoding EAAT3 (<b>B</b>, n = 9) or EAAT4 (<b>D</b>, n = 6) without (open circles) and with (closed circles) additional coexpression of Klotho. The values were fitted to a hyperbola function.