Figure 7

Paired pulse facilitation and long-term potentiation. (a) Facilitation ratios evaluated at 50-millisecond (msec) intervals; scale: 0.5 mV, 10 msec. The facilitation ratio values were computed as the ratio of the second stimulus-evoked fEPSP peak divided by the first stimulus-evoked fEPSP peak. The facilitation ratios of WT (white bar) and KO (black bar) hippocampal slices (WT: n = 7; KO: n = 9) were calculated from the averaged facilitation ratio values. (b) Average traces recorded at times 1 and 2; scale: 0.5 mV, 5 msec. The arrow indicates the time when the tetanic stimulation {100 Hz 1 sec × 2 (10 sec apart)} was applied. Regarding LTP, the normalized EPSP slope for WT mice 40 minutes after the tetanus was 185% ± 6.9% of the mean slope before stimulation, and that for KO mice was 192% ± 4.0%. There was no significant difference in the magnitude of LTP in WT and KO hippocampus slices (WT: n = 7; KO: n = 9) (p = 0.372). Data were given as mean (±SEM) and were analyzed with Student’s t-test.