FIGURE 5.

Photorelease of γ-aminobutyric acid (GABA) from ruthenium-bipyridine-triphenylphosphine–GABA (RG) significantly reduces the duration of neocortical seizures. For each animal, the seizure durations before, during, and after blue light illumination were compared. Seizure duration was not affected by illumination in the absence of RG (a, p > 0.4, 1-way repeated measures analysis of variance [ANOVA] on ranks). However, illumination (30 or 60 seconds) significantly reduced the duration of seizures in the presence of different concentrations of RG (b, c, p < 0.05 and p < 0.001, respectively, compared to preillumination and postillumination durations; 1-way repeated measures ANOVA followed by Student-Newman-Keuls; n = 7 or 8 animals in each group). Picrotoxin (PTX; 100µm) eliminated the effect of RG illumination (n = 4 animals). Focal dural reservoir application of GABA at seizure onset also had no effect on seizure durations (n = 8 animals). There was no significant difference in seizure durations before and after illumination across all the groups, indicating no effect of RuBi-GABA on seizure durations in the absence of illumination (p > 0.4 by ANOVA). The shaded bars for focal GABA administration represent before, during, and after GABA application, not illumination.