Fig. 2

Hippocampal depotentiation does not rely on GSK3β. (a) The GSK3 inhibitor SB216763 (10 μM; represented by an open rectangle) was added 30 min prior to TBS application until 15 min after DP induction in a subset of hippocampal slices from 2 to 3 month-old- C57Bl/6 J mice (n = 11). No significant effect was observed compared to DP controls (n = 9) (p = 0.614). DP was clearly induced in both conditions since highly significant differences were detected when compared to LTP controls (n = 10) (DP 8: F _{(1, 17)} = 19.71, ***p = 0.0004; DP 8 + SB216763: F _{(1, 19)} = 21.49, ***p = 0.0002). Arrow represents single TBS, open square represents TPS. Error bars represent SEM. Traces show representative examples of field excitatory postsynaptic potentials (fEPSP) recorded during baseline, 1 min post-TBS delivery (IP 1 min), 1 min post-TPS delivery (DP 1 min), and 120 min post-TPS delivery (DP 120 min). Calibration bars: 0.5 mV and 5 ms. (b) Replicating same experiments in aged (17–19 month-old) C57Bl/6 J mice (n = 7) equally failed to show significant effects of SB216763 (10 μM; represented by an open rectangle) on DP compared to DP controls (n = 6) (p = 0.857). When compared to LTP (n = 6), either DP condition showed a significant LTP reversal (DP 8: F _{(1, 10)} = 6.193, *p = 0.0321; DP 8 + SB216763: F _{(1, 11)} = 7.458, *p = 0.0195). Arrow represents single TBS, open square represents TPS. Error bars represent SEM. Traces show representative examples of field excitatory postsynaptic potentials (fEPSP) recorded during baseline, 1 min post-TBS delivery (IP 1 min), 1 min post-TPS delivery (DP 1 min), and 120 min post-TPS delivery (DP 120 min). Calibration bars: 0.5 mV and 5 ms