Research Article

ZD7288 Enhances Long-Term Depression at Early Postnatal Medial Perforant Path-Granule Cell Synapses

Figure 3

ZD7288 enhances the paired-pulse ratio in early postnatal, but not adult, rats. (a) The time course of the fEPSP amplitude following LFS in adult (P30–60, open symbols) and early postnatal rats (P9–15, closed symbols) shows no LTD in the presence of the NMDA receptor blocker D-AP5 (50 μM, indicated by a black bar). Representative fEPSPs were taken at the beginning (indicated by “1”) and at the end (indicated by “2”) of the experiment. (b) The bar graph summarizes the STD and LTD levels in both adult (open bars) and early postnatal rats (closed bars) in the presence of D-AP5. (c) The time course of the fEPSP amplitudes (normalized to the fEPSP1 baseline) following paired-pulse stimulation (interpulse interval 40 ms) delivered to the MPP in early postnatal rats (P9–15) shows that ZD7288 (indicated by a black bar) depressed the first response (fEPSP1, gray boxes) more markedly than the second response (fEPSP2, gray diamonds). Representative fEPSPs were taken at the beginning (indicated by “1”) and at the end (indicated by “2”) of the experiment. (d) The time course of the fEPSP amplitudes (normalized to the fEPSP1 baseline) following paired-pulse stimulation (interpulse interval 40 ms) delivered to the MPP in adult rats (P30–60) shows that ZD7288 (black bar) depressed the first (fEPSP1, open boxes) and the second response (fEPSP2, open diamonds) to the same degree. Representative fEPSPs were taken at the beginning (indicated by “1”) and at the end (indicated by “2”) of the experiment. (e) Time courses of the PPR (normalized to baseline PPR) in both age groups: adult (open symbols) and early postnatal rats (gray symbols). Note that ZD7288 increased PPR only in early postnatal animals. (f) The bar graph summarizes the normalized paired-pulse ratio of both age groups recorded before and after ZD7288 treatment. ZD7288 significantly increased the PPR in early postnatal, but not in adult, animals. All data are mean ± SEM.
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