Figure 4.

The steady-state inactivation curve of I_K(DR) in the control period (i.e., VOR was not present) and during cell exposure to 10 or 30 μM VOR. The experiments were conducted with a two-step voltage protocol (indicated in the uppermost part of (A)). (A) Representative current traces obtained in the absence (upper) and presence of 10 μM VOR (middle) or 30 μM VOR (lower). (B) The relationships of the conditioning potential versus the normalized amplitude of I_K(DR) in the control period (open black squares) and during cell exposure to 10 μM VOR (filled black circles) or 30 μM VOR (open red circles). The data represents the mean ± SEM (n = 8 for each point). The continuous curves were obtained with the goodness-of-fit test by a Boltzmann function, as described in Materials and Methods.