XB-IMG-120407
Xenbase Image ID: 120407
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Figure 4. . Kinetics of hyperpolarization-induced unblock of IRK1 channels in the presence of bis-QAC10. (A) Current transient elicited by stepping membrane voltage from 100 to −40 mV in the presence of 1 mM bis-QAC10, where the first 0.3 ms of the trace was omitted. The curve superimposed on the transient (and back extrapolated to the start of depolarization) is a single-exponential fit. (B) The natural logarithm of the reciprocal of the time constants (mean ± SEM; n = 3) for channel unblock (1/τoff, an estimate of the apparent off rate constant appkoff), obtained as shown in A, is plotted against bis-QAC10 concentration for five voltages. The lines through the data represent, for a given voltage, the average over the three concentrations tested. (C) The natural logarithm of the average appkoff from B is plotted against membrane voltage. The line through the data is a fit of the Boltzmann function, yielding koff(0 mV) = 1.06 ± 0.07 × 102 s−1 (mean ± SEM, n = 3) and zoff = 1.46 ± 0.02. Image published in: Shin HG and Lu Z (2005) Copyright © 2005, The Rockefeller University Press. Creative Commons Attribution-NonCommercial-ShareAlike license Larger Image Printer Friendly View |