Fig. 2. Voltage dependence of rosiglitazone-mediated inhibition of Kv3.1 currents.
The Kv3.1 currents were elicited by applying 300-ms depolarizing pulses between –50 and +70 mV in 10-mV increments every 10 sec from a holding potential of –80 mV under control conditions (A), and in the presence of 30 µM rosiglitazone (B). The dotted lines in (A) and (B) represent zero current. (C) The amplitudes of Kv3.1 currents were measured at the end of test pulses and plotted against membrane potentials, in control (○) and 30 µM rosiglitazone (●). (D) The activation curve of control Kv3.1 current was constructed from tail current amplitudes at –40 mV after 300-ms depolarizing pulses between –50 and +70 mV in 10 mV. Only the Boltzmann fitting curve is shown (dotted line, normalized current y-axis for activation curve). In order to compare with the activation profile, the percent inhibition of Kv3.1 current by rosiglitazone was plotted (■). The solid line was drawn from a linear curve fitted to the relative current data between +30 and +70 mV. Data are expressed as mean ± SEM.
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