FIGURE LEGENDS
Fig. 1. Recovery from inactivation in the absence and presence
of 100 µM riluzole in WT channels. The RFI protocol is shown in the
upper panel. The duration of the hyperpolarizing gap between the two
depolarizations is progressively increased. Peak amplitudes of the 2nd
pulse-evoked currents are plotted against hyperpolarizing gap duration.
Thin black lines – normalized control amplitudes in n = 9 cells, thin
red lines – amplitudes in the same 9 cells in the presence of 100 µM
riluzole. The effect of riluzole in each cell was normalized to the
control in the same cell. Averaging (thick lines) was performed as
described in Methods.
Fig. 2. Effect of riluzole perfusion as monitored with the 3PT
protocol on WT channels. A The voltage protocol. Blue, red, and green
color indicate 1st, 2nd, and
3rd depolarizations, respectively, as in panels D to
F.
B Example of sodium currents evoked in a typical WT channel
expressing cell by the three depolarizations of the 3PT protocol.
Subsequent traces are overlaid on each other. Blue traces show control,
dark to light red show successive traces during riluzole application,
light gray to black traces show successive traces during washout.
C The same currents after subtraction of capacitive and leakage
artifacts.
D Illustration of the first 29 consecutive trains (protocol in
the upper panel), and the currents evoked by them (lower panel). Peaks
of 1st, 2nd, and
3rd pulse-evoked currents are marked with blue, red,
and green circles, respectively. Shaded area indicates the perfusion of
100 μM riluzole.
E Amplitude plots for 7 individual cells. Connecting peak
amplitudes of 1st (blue), 2nd (red),
or 3rd (green) pulse-evoked currents gives a plot of
peak amplitudes throughout the whole experiment. To help compare the
extent of inhibition, 1st, 2nd, and
3rd pulse-evoked currents were normalized each to its
own control (peak amplitudes recorded during the first train).
F Onset and offset time constants (mean ± SEM) for the
amplitude plots of the seven cells shown in panel E. Data from one
individual cell (the same as in panels B to D) are shown for
illustration. Mono- or bi-exponential functions were fitted to traces
after correcting for slow inactivation (see Methods). Dashed lines show
exponentials fitted to this particular cell.