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. Author manuscript; available in PMC: 2009 Sep 28.
Published in final edited form as: Heart Rhythm. 2009 May 18;6(9):1318–1326. doi: 10.1016/j.hrthm.2009.05.016

Figure 5.

Figure 5

Time-dependent parameters of WT-delQ and V1340I-delQ. (A) Recovery from fast inactivation estimated by a double-pulse protocol. Cells were depolarized at 0 mV for 500 ms from a holding potential of −140 mV, then stepped to −140 mV for various duration before the 2nd pulse (20 ms at −20 mV). Fractional recovery was calculated as a ratio of peak currents at the second pulse. The time course was fitted with a double-exponential function: I(t)/Imax = C − Af × exp(−t/τf) − As × exp(−t/τs), where t is the recovery time, Af and As are the fraction of fast and slow components, τf and τs are the time constants of fast and slow components of recovery. (B) Closed-state inactivation. Membrane potential was held at −100 mV for various durations (Δt) from a holding potential of −140 mV before the test pulse (20 ms at −20 mV). The normalized currents by the maximal currents (t = 1 ms) were plotted against Δt. Data were represented as mean ± SE.