LTP is impaired in <i>Lrp4</i>^{<i>ECD/ECD</i>} but not in <i>Lrp4</i>^{<i>ΔICD/ΔICD</i>} mice.

Abstract

<p><b>A</b>: <i>Upper Panel</i>, Sample traces before and 40 min after theta-burst stimulation (TBS); <i>Lower Panel</i>, Results of experiments from <i>Lrp4</i>^{<i>ECD/ECD</i>} mice compared to their <i>Lrp4</i>^{<i>WT-KI/WT-KI</i>} controls. TBS induced on average a 37.63 ± 7.88% increase in <i>Lrp4</i>^{<i>WT-KI/WT-KI</i>} control slices (open squares, n = 16, N = 5), but only 14.83 ± 3.39% LTP in slices from the <i>Lrp4</i>^{<i>ECD/ECD</i>} mice (black triangles, n = 10, N = 3). <b>B</b>: Unpaired t-test was used to compare each sample for LTP calculated 40–60 min after theta-burst. Values are the means of the normalized fEPSP slopes. * denotes significance, p = 0.0387. <b>C:</b><i>Upper Panel</i>, Sample traces before and 40 min after TBS. <i>Lower Panel</i>, Results of experiments from <i>Lrp4</i>^{<i>ΔICD/ΔICD</i>} mice compared to their <i>Lrp4</i>^{<i>WT-KI/WT-KI</i>} controls. <i>Lrp4</i>^{<i>WT-KI/WT-KI</i>} slices were recorded on consecutive days and used as internal controls and pooled together. TBS induced a 37.63 ± 7.88% LTP in <i>Lrp4</i>^{<i>WT-KI/WT-KI</i>} control slices (open squares, n = 16, N = 5), and 32.42 ± 6.27% LTP in slices from the <i>Lrp4</i>^{<i>ΔICD/ΔICD</i>} mice (gray filled rhombus, n = 11, N = 5). <b>D</b>: There was no significant difference in LTP between <i>Lrp4</i>^{<i>WT-KI/WT-KI</i>}<i>and Lrp4</i>^{<i>ΔICD/ΔICD</i>} mice (p = 0.63). <b>E.</b> Input-output curves calculated as a function of fiber volley amplitude to the slopes of fEPSP’s. Average peak amplitudes for <i>Lrp4</i>^{<i>WT-KI/WT-KI</i>}, <i>Lrp4</i>^{<i>ECD/ECD</i>} and <i>Lrp4</i>^{<i>ΔICD/ΔICD</i>} slices used in the experiments were 1.68 ± 0.15 mV, 1.27 ± 0.25 mV, and 1.50 ± 0.20 mV), respectively, and were not significantly different from each other. (One-way ANOVA, F = 1.124, p = 0.33.) <b>F:</b> Theta-burst analysis or <b>G:</b> paired pulse ratios (n = 8, N = 3 for each) did not reveal any significant differences between <i>Lrp4</i>^{<i>WT-KI/WT-KI</i>} and <i>Lrp4</i>^{<i>ECD/ECD</i>} (two-way ANOVA, F(3,56) = 0.46, p = 0.71). N = number of animals.</p