Figure 5.

EEG delta power (1.0–4.0 Hz) during the GBL- and BAC-induced state and its time course during subsequent NREMS (mean ± SEM). A, Delta power during GBL-induced state (triangles) increased from 50 to 100 mg/kg, where it reached a plateau (50 mg/kg, <3 highest doses in 1a^−/− and 1b^−/− mice; one-way ANOVA, Tukey's test, p < 0.05). Plateau levels reached were around twofold higher in 1a^−/− mice than in 1b^−/− and WT mice (one-way ANOVAs, p < 0.0001; Tukey's tests, p < 0.05, stars). For NREMS delta power (circles; mean ± SEM), a comparison among genotype (1a^−/−, 1b^−/−, WT), day (1–5), and time (18 intervals per d) was performed (three-way ANOVA, factor genotype, time, p < 0.0001; factor day, p = 0.0003; interaction genotype × day, p = 0.0020; genotype × time, p = 0.040; time × day, p = 0.10; genotype × day × time, p = 0.10). Although the time course of NREMS delta power did not differ among the three genotypes, the overall dynamic range was smaller in 1b^−/− and larger in 1a^−/− mice compared with WT mice (Tukey's tests, p < 0.05). For NREMS delta power, differences among drug days were observed, but not in a dose-dependent manner (Tukey's test, 150 = saline = 50 = 100 > 50 = 100 = 300 mg/kg). B, Delta power during BAC-induced state (black triangles) did not increase with dose in WT mice (one-way ANOVA, p = 0.64). BAC affected the time course of delta power in NREMS [circles; two-way ANOVA factor day (1–4), p = 0.079; factor time (18 intervals per d), p < 0.0001; interaction, p < 0.0001]. A large increase in NREMS delta power occurred after the BAC-induced state, followed by a decrease below saline levels during the subsequent dark period (white triangles mark significant differences from saline; Dunnett's two-tailed t test, p < 0.05). Note the dose-dependent decrease in delta power during the dark period (one-way ANOVA, factor day, p < 0.0001; saline > 5 = 7.5 > 7.5 = 10 mg/kg; Tukey's test, p < 0.05).