Figure 7.

Altered synaptic function in adult Dab1 cKO mice. Hippocampal slices were obtained from 3- to 6-month-old WT and Dab1 cKO mice. A, Normal synaptic transmission was observed when comparing the slope of the field EPSP versus the fiber volley amplitude at increasing intensities for WT (●, n = 11 slices, 4 mice) and cKO mice (○, n = 18 slices, 4 mice). B, Short-term synaptic plasticity was evaluated by the amount of PPF with IPIs ranging from 20 to 300 ms in WT (●, 20 slices, n = 5 mice) and cKO mice (○, 34 slices, n = 6 mice). Significant reductions in PPF were found at the 40 ms IPI (*p < 0.05). C, LTP was induced with TBS. The first and final 10 min of recording were averaged separately, revealing both a reduction in LTP induction (*p < 0.05) and maintenance (*p < 0.05) in Dab1 cKO (●, 15 slices, n = 7 mice) compared with WT controls (●, 13 slices, n = 6 mice), respectively. Representative traces are included. Scale bar, 5 ms. D, LTP was induced by HFS consisting of two trains at 100 Hz in WT (●, 8 slices, n = 4 mice) and Dab1 cKO mice (○, 11 slices, n = 5 mice). A reduction of LTP in cKO slices compared with WT was observed when the final 20 min of recording was averaged (*p < 0.05), but not the first 10 min. Representative traces are included. Scale bar, 5 ms. E, Mock- and Reelin-conditioned medium was applied for 10 min before inducing LTP with TBS (indicated by gray line). Reelin treatment (■, 8 slices, n = 3 mice) was found to enhance LTP relative to mock treatment (●, 15 slices, n = 5 mice) in WT mice (*p < 0.05). F, Reelin-conditioned medium (□, 9 slices, n = 3 mice) had no effect on TBS-induced LTP in Dab1 cKO slices when compared with mock medium (○, 7 slices, n = 3 mice). For all data representation, except A, measurements from individual slices were averaged per mouse.