Figure 5. Kv2.1 and Kv2.1/Kv9.3 currents in HEK293 cells.

A, representative families of whole-cell currents due to expression of Kv2.1 (upper) and Kv2.1/Kv9.3 (lower) channels in HEK 293 cells recorded at 22 and 35°C (left and right, respectively). Voltage steps of 325 ms duration between −95 and +45 mV in increments of 10 mV prior to repolarization to −55 mV were applied from a holding potential of −75 mV. B, mean values ± s.e.m. (n = 6 and 8, respectively) for current density (pA pF⁻¹) versus voltage relation for Kv2.1 and Kv2.1/Kv9.3 channels in HEK 293 cells at 22°C. C, representative Kv2.1 and Kv2.1/Kv9.3 currents recorded in response to command steps to between −55 and −25 mV and between −65 and −45 mV, respectively. Note the activation of current due to heteromultimeric, but not homomultimeric, channels at −55 mV. D, representative families of expanded Kv2.1 and Kv2.1/Kv9.3 tail currents recorded at −50 mV at 22°C illustrating the significantly slower deactivation kinetics of the heteromultimeric channels.