Figure 7. Cs⁺ substitution selectively attenuates open-state dependent inactivation.

A and B, cells stably expressing full-length Kv1.5 or Kv1.5ΔN209 were pulsed from a holding potential of −80 mV to +60 mV with either K⁺ or Cs⁺ as the permeant ion. Inactivation–voltage relationships for Kv1.5 (C) and Kv1.5ΔN209 (D) were determined as described in Fig. 1, with K⁺ or Cs⁺ in both the pipette and extracellular solutions. In D the inactivation–voltage relationships collected for full-length Kv1.5 are superimposed in grey, for comparison.