Figure 11. The ability of quinidine to increase the rate of inactivation in fKv1.4[V561A]ΔN channels is [K⁺]_o independent.

A, in the presence of 2 mm[K⁺]_o, τ_{inactivation,2K}= 2.164 ± 0.135 s. Addition of 1 mm quinidine increases the rate of inactivation to τ_{inactivation,2K,1mMQ}= 1.706 ± 0.132 s. B, in the presence of 98 mm[K⁺]_o,τ_{inactivation,98K}= 1.529 ± 0.066. The addition of 1 mm quinidine further increases the rate of inactivation: τ_{inactivation,98K,1mMQ}= 1.300 ± 0.079 s.