Dependence of the gating factor R_k (closed squares, Eq. 4a) and R_I (open circles, Eq. 4b) on membrane potential as calculated from the data in Fig. 6, A and B, and Fig. 5, A and B, respectively. The flickering bursts occurring in records at 50 mM Tl⁺ were very short due to sojourns in very short closed events. There, I_app,∞ was obtained from the expectance of current from the distributions per level (Schroeder et al., 2004). They coincided with I_app,k, indicating the high reliability of the β fit. The smooth lines present the free fits of R_k (Eq. 5, with the parameters in Table I). Dashed lines are joint fits for 0/25 mM Tl⁺ and 50/150 mM Tl⁺, respectively. Errors bars represent SEM. Number of data points are given at the curves.