XB-IMG-124586
Xenbase Image ID: 124586
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Figure 4. Kinetics of depolarization-induced recovery from CNGA1 block by extracellular PhTx. (A) Current transient elicited by stepping the membrane voltage from â200 to â50 mV in the presence of 0.1 µM of extracellular PhTx. The superimposed curve is a single-exponential fit. (B) Natural logarithm of the reciprocal of the time constant (mean ± SEM; n = 4â6) for channel unblock (1/Ïoff, an estimate of the apparent off-rate constant koff) at four voltages, obtained from fits as shown in A, is plotted against the concentration of extracellular PhTx. Lines through the data represent averages over the three concentrations tested at each voltage. (C) Natural logarithm of koff from B is plotted against membrane voltage. The plot is fitted with the equation ln koff = ln koff (0 mV) + zoffVF/RT, yielding koff (0 mV) = 9.65 ± 0.35 à 103 sâ1 and zoff = 1.31 ± 0.02. Image published in: Martínez-François JR and Lu Z (2010) © 2010 Martínez-François and Lu. Creative Commons Attribution-NonCommercial-ShareAlike license Larger Image Printer Friendly View |