Current decay of myotonia mutant channels.

<p>The time constant of decay is altered in hNa<sub>V</sub>1.4<sub>F1705I</sub> compared to wild type hNa<sub>V</sub>1.4 channels. (<b>A</b>) Superimposed normalized currents through wild type and hNa<sub>V</sub>1.4<sub>F1705I</sub> channels at test pulses of −30, −20, and −10 mV exhibiting slowing of current decay in the mutant channel. (<b>B</b>) The time constants of current decay of hNa<sub>V</sub>1.4<sub>F1705I</sub> channels are significantly different compared to wild type in the absence (p<0.05) or presence of 0.5 µM of Ca<sup>2+</sup> (p<0.001). The inset is an expanded view −20 mV to 0 mV. (<b>C</b>) Raw current traces of hNa<sub>V</sub>1.4<sub>F1705I</sub> channels at RT and at 37°C. Currents were measured at −20 mV, in the same cell at different temperatures with 0.5 µM of Ca<sup>2+</sup> in the pipette. (<b>D</b>) Plot of the time constants of current decay of wild type and hNa<sub>V</sub>1.4<sub>F1705I</sub> channels at RT and at 37°C in 0.5 µM of Ca<sup>2+</sup>. Paired measurements were made at RT and at 37°C. The current decay of hNa<sub>V</sub>1.4<sub>F1705I</sub> is significantly different at 37°C compared to RT (p<0.05). (<b>E</b>) Plot of the steady-state inactivation of hNa<sub>V</sub>1.4<sub>F1705I</sub> channels at 37°C in 0.5 µM of Ca<sup>2+</sup>. For comparison the steady-state inactivation of wild type and hNa<sub>V</sub>1.4<sub>F1705I</sub> from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0081063#pone-0081063-g001" target="_blank">Figure 1E</a> are re-plotted. The symbols are the same in plots B, D and E.</p>

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