Figure 5

Onset and offset of drug effects in the 3PT protocol. Plots of peak amplitudes for the 1^st, 2^nd, and 3^rd pulse-evoked currents are shown in blue, red and green lines, respectively. Thin lines show measurements from individual cells, thick lines show averages. Recordings from individual cells were aligned to the moment of wash-in and wash-out for comparability, with 0 to 767 s of recording not shown between the onset and offset. Ten control trains (3.3 s) are shown before drug applications, and the last 20 trains (6.6 s) of drug application before wash-out. (a) 100 µM riluzole, (b) 10 µM riluzole, (c) 100 µM azido-riluzole, (d) 100 µM azido-riluzole with UV irradiation (shown on a contracted time scale below onset and offset). (e) Plot of 2^nd/1^st pulse-evoked (upper curves) and 3^rd/1^st pulse-evoked (lower curves) amplitude ratios for the onset and offset of: 10 µM riluzole (yellow lines), 100 µM riluzole (red lines), 100 µM azido-riluzole (blue lines), and 100 µM azido-riluzole with ~3 min UV irradiation (green lines) between onset and offset.