Figure 4

HDAC inhibition restores mTORC1 dependent mGluR-LTD in adult TSC2^+/− mice. (A) Adult WT mouse hippocampal slices (6–8 weeks old) exhibit LTD with (S)-DHPG (50 µM for 10 minutes; shown in blue, n = 5 slices from 4 mice) that is reduced in magnitude with rapamycin (20 nM for 20 minutes; shown in red, n = 8 slices from 4 mice; two-way ANOVA: F(1,15) = 7.375, p = 0.0159).The addition of the class I HDAC inhibitors, TSA (B, 1.65 µM; shown in purple, n = 5 slices from 4 mice) and VPA (C, 250 nM; shown in yellow, n = 6 slices from 4 mice) does not alter the acquisition of mGluR-LTD (B: two-way ANOVA: F(1.9) = 2.081, p = 0.1831. C: two-way ANOVA: F(1,11) = 0.1725, p = 0.6858) nor does it affect rapamycin sensitivity in adult WT hippocampal slices (shown in red for both; B: n = 7 slices from 4 mice; two-way ANOVA: F(1,11) 12.27, p = 0.0050; C: n = 7 slices from 5 mice; two-way ANOVA: F(1,10) = 9.629, p = 0.0112). D) Adult TSC2^+/− mice exhibit LTD with (S)-DHPG (shown in blue, n = 8 slices from 4 mice) that is not sensitive to rapamycin (shown in red, n = 9 slices from 5 mice). E) Acquisition of mGluR-LTD is not altered in TSC2^+/− slices treated with TSA (untreated slices shown in blue, n = 8 slices from 5 mice; TSA treated slices shown in purple n = 8 slices from 5 mice; two way ANOVA: F(1,18) = 1.271, p = 0.2743). TSC2^+/− slices treated with TSA exhibit rapamycin sensitivity (shown in red, n = 6 slices from 5 mice; two-way ANOVA: F(1,12) = 7.566, p = 0.0176). F) VPA also restores rapamycin sensitivity in adult TSC2^+/− slices (shown in red, n = 9 slices from 5 mice) and produces a decreased magnitude compared to slices treated with only VPA (shown in yellow, n = 7 slices from 5 mice; two-way ANOVA: F(1,14) = 6.054, p = 0.0275).