Dependence of the rate constants of a two-state model on luminal Tl⁺ concentration at different membrane potentials as obtained from the β distributions of the current amplitudes in the bursts for (A) k_OC and (B) k_CO. C and D present tests of whether the absolute values in A and B are determined correctly. The black histograms are generated from the measured time series. The coinciding red curves result from simulated time series using the rate constants in A and B with (C) 50 mM Tl⁺ at −100 mV and (D) 150 mM Tl⁺ at −80 mV (a = 1 in Eq. 2). The deviating histograms (green) are obtained by multiplying the rate constants k_CO and k_OC in Eq. 2 with a common factor of (C) a = 0.33 and (D) a = 2.