Normal fEPSP-LTD and transient increment of early LTP in young IP₃K-A Tg mice.

<p>(A), LFS-induced LTD. Upper plot, LTD was induced by LFS protocol (1 Hz, 900 pulses) at the CA1 dendritic region of the hippocampal slice. The slope of fEPSP was 81.1 ± 1.5% (WT, n = 10 slices, 4 mice) and 84.0 ± 1.0% (Tg, n = 10, 4) at 60–65 min on the time axis (<i>p</i> = 0.11). Inlet traces are sample traces measured at baseline (1, thin line) and at 65 min (2, dashed line), respectively. Scale bars: 0.5 mV, 8 msec. Lower plot shows the normalized PPF ratio of the fEPSP slopes. PPF was measured at 60 to 65 min after induction of LTD (WT, 1.06 ± 0.80E-2; Tg, 1.02 ± 0.79E-2). (B), Single theta-burst induced LTP. Upper plot, LTP was induced with a single theta-burst protocol. Significant difference was observed immediately for 2–6 min after the theta-burst protocol (2, bar): WT, 141.5 ± 2.1%, n = 15; Tg, 160.6 ± 2.8%, n = 20; **<i>p</i> < 0.001. At 58–62 min (3), WT, 115.9 ± 2.0%; Tg, 118.9 ± 1.9% of baseline; <i>p</i> = 0.28. Inlet traces are sample traces indicating baseline (1, thin line), early peak (2, thick line) and late phase (3, dashed line). Scale bars for all sample traces: 0.5 mV, 8 msec. Lower plot shows the normalized PPF ratio of the fEPSP slopes. At 2–6 min, WT, 0.95 ± 0.62E-2; Tg, 0.95 ± 0.60E-2. At 58–62min, WT, 1.00 ± 0.98E-2; Tg, 0.99 ± 0.50E-2. (C), Four theta-burst induced LTP. LTP was induced with four theta-burst protocol. Significant difference was observed immediately after the theta-burst protocol (2, bar): WT, 155.0 ± 2.3%, n = 6; Tg, 169.1 ± 4.2%, n = 8; <i>p</i> = 0.027. At 78–82 min (3), WT, 125.3 ± 4.5%; Tg, 123.5 ± 3.1% of baseline; <i>p</i> = 0.74. Inlet traces are sample traces indicating baseline (1, thin line), early peak (2, thick line) and late phase (3, dashed line). Scale bars: 0.5 mV, 8 msec. Lower plot shows the normalized PPF ratio of the fEPSP slopes. At 17–20 min (2), WT, 0.87 ± 0.012; Tg, 0.94 ± 0.014; **<i>p</i> = 0.002. At 78–82 min (3), WT, 0.97 ± 0.011; Tg, 0.99 ± 0.021.