Fig. 1
Effect of SGX treatment on I K(DR) in differentiated NSC-34 neuronal cells. In these experiments, cells were bathed in Ca2+-free Tyrode’s solution containing 1 μM tetrodotoxin and the recording pipette was filled with K+-containing solution. The treated cells were incubated with SGX (30 μM) for 1 h at 37 °C. (A) Bar graph showing the data of I K(DR) amplitude when cells were treated with 10, 30 and 100 μM SGX. Current amplitudes were measured at the beginning of depolarizing voltage was obtained at the 60th milliseconds after the initial rise of voltage from −50 to +50 mV (mean ± SEM; n = 10–12 for each bar). *Significantly different from control (P < 0.05). (B) Superimposed current traces obtained in untreated (upper) and SGX-treated (lower) cells. The cells examined were held at −50 mV and the voltages ranging from −50 to +60 mV in 10-mV increments were applied, as whole-cell recordings were established. The uppermost part indicates the voltage protocol used. (C) Current amplitude versus membrane potential relationships of I K(DR) in untreated cells (square symbols) and in cells treated with 30 μM SGX (circle symbols). In C(a) and C(b), I K(DR) amplitude was measured at the beginning (filled symbols) and end (open symbols) of depolarizing steps, respectively. I K(DR) amplitudes measured at the beginning of depolarizing voltage were obtained at the 60th milliseconds after the initial rise of voltage. Each point represents the mean ± SEM (n = 10–12). *Significantly different from controls [i.e., I K(DR) amplitude at the same level of voltage step] (P < 0.05)