XB-IMG-118409
Xenbase Image ID: 118409
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Figure 8. Nonohmic behavior of tail current amplitude at negative potentials is associated with nonohmic reductions in apparent average single channel current amplitude. In A, binned Ï2/I relationships for four sets of 100 steps to +240 mV are displayed along with the best fit of Eq. 1 with i = 21.15 pA; N = 1146. In B, the tail currents (10 kHz filtering) after repolarization to â60 (black), â100 (red), â140 (blue), and â180 (green) mV from the initial step to +240 mV are shown on a logarithmic time base to emphasize the two exponential nature of the tail current decay. The peak of the tail current is essentially unchanged between â100 and â180 mV. In C, the binned Ï2/I relationships for each of the tail currents shown in B are shown. N was constrained to the value obtained in B (N = 1146) and i obtained from the fit of Eq. 1. Apparent single channel current amplitude does not increase at potentials more negative than â100 mV, despite the increase in driving force. In D, the estimated i from examples like that in C are plotted as a function of voltage (red symbols), along with the estimates of i obtained from Ï2/I analysis at positive potentials. Blue symbols correspond to records filtered at 50 kHz and red symbols to those filtered at 10 kHz. Image published in: Zhang X et al. (2006) Copyright © 2006, The Rockefeller University Press. Creative Commons Attribution-NonCommercial-ShareAlike license Larger Image Printer Friendly View |