Figure 3. Ii_deac kinetics of K_v3.1b as a function of activating pulse duration.

(a) Ionic current deactivation (Ii_deac) of K_v3.1b elicited using the pulse protocols shown on top. From left to right the activating pulse at +40 mV was increased from 5 to 50 ms, and to 100 ms. (b) Left panel shows a superposition of Ii_deac at −10 mV following a 5-ms (black), a 50-ms (red) and a 100-ms (blue) long activating pulse. Right panel displays a superposition of the same Ii_deac currents after rescaling them. Note the slowing in Ii_deac decay time (τ_Iideac) when the duration of the activating pulse was increased. (c) Voltage dependence of the weighted τ_Iideac as a function of activating pulse duration at +40 mV, shown as mean±s.e.m. (n=5). When the duration time was increased from 2 ms (white) up to 50 ms (green) there was a gradual deceleration in τ_Iideac. Note that depolarizations longer than 50 ms in duration did not cause any further significant changes in τ_Iideac. (d) Weighted τ_Iideac at −60 mV as a function of depolarization time. This plot shows, in contrast to Ig_deac kinetics, that the Ii_deac kinetics displayed only a single slowing process, which developed with a time constant of 6.6±1.7 ms (n=5, data represented as mean±s.e.m.).