Figure 8.

Effects of Ts3 on the fluorescence changes that track the movement of the S4 segment of domain IV of mutant channels L1439C stained with TMRM. Traces were recorded as described in Fig. 6. (A) Sodium currents recorded at −20 mV before and after the treatment with 200 nM Ts3. (B) Fluorescence signals obtained at −20 mV before (black trace) and after (gray trace) the treatment with 200 nM of Ts3. The signals are shown as ΔF/F (%), where F is the fluorescence background. The arrow indicates the direction in which fluorescence increases. These experiments were performed at room temperature. (C) F-V curves obtained before (white symbols) and after (black symbols) the treatment with 200 nM of Ts3 (mean ± SEM, n = 3; paired experiments). Solid lines are the curves obtained by fitting the data with the function 3.