RPR260243 has no effect on hERG1 channel gating currents. (A) Gating currents for WT hERG1 channels measured at test potentials of −10 and +40 mV before (black traces) or 25 min after exposure of an oocyte to 30 µM RPR260243 (red traces). For these experiments, the currents were filtered at 5 kHz and digitized at 20 kHz. (B) Average Q_OFF-V relationships determined under control conditions and after the treatment of the same oocytes with 30 µM RPR260243 for 20–25 min (n = 5). Q_OFF was normalized to the peak of the control value for each oocyte. Data were fitted with a Boltzmann function (smooth curves). In control conditions, V_1/2 = −18.6 ± 0.5 mV and z = 1.84 ± 0.01. In the presence of RPR260243, V_1/2 = −19.0 ± 0.5 mV and z = 1.88 ± 0.01.