Figure 2. Kinetics of hERG charge movement and ionic activation at 0 mV and +60 mV. Representative trace of gating currents evoked by steps to (A) 0 mV extending in 50 ms increments or (B) +60 mV in 10 ms increments. (C) Representative trace of ionic currents evoked by steps to 0 mV extending in 60 ms increments or (D) +60 mV in 10 ms increments. Plot of the normalized Q_off (●) and normalized peak ionic tail currents (○) after increasing durations of a 0 mV (E) or +60 mV (F) conditioning step. Charge movement was fit with a single exponential ($y=y_0+ A{e}^{-t/ô}$) and ionic currents with a delayed exponential $y=\left(A{(1-e}^{-\left( t-t_0/ô \right)})\right).H(t-t_0)$ where y is the normalized response, t is the duration of the conditioning pulse, A the amplitude, τ the time constant and H the unit step function where t₀ is the delay before onset of the exponential rise. (G) Time constants for gating charge movement and ionic current activation at 0 and +60 mV.