Figure 5.
Riluzole concentration‐dependently potentiated GABA responses from heterologously expressed receptors in Xenopus oocytes. (A) Sample recordings showing the potentiation of the response to 2 μM GABA induced by different concentrations of riluzole. With high concentrations of riluzole, GABA responses usually displayed apparent desensitization. (B) Concentration dependence of the effect of riluzole on the responses to 2 μM GABA. Normalized potentiation relative to the peak potentiation by 300 μM riluzole is plotted against riluzole concentration. Smooth curves are fit to the Hill equation. The Hill coefficient is 2.4, and riluzole EC50 (the concentration of riluzole that induces half‐maximal potentiation) is 58.7 μM (n = 5). Before normalization, the amplitudes of potentiation caused by different concentrations of riluzole were: 75.7 ± 7.1% from 30 μM riluzole, 208.0 ± 16.1% from 70 μM riluzole, 353.6 ± 38.1% from 150 μM riluzole, and 370.8 ± 61.5% from 300 μM riluzole. Reprinted from [104], copyright (2002), with permission from Elsevier.