GluN2A does not alter the number of primary dendrites in dentate granule cells.

<p>(<b><i>A, B</i></b>) Representative images of Golgi-impregnated cells from the inner granular zone (IGZ, <b><i>A</i></b>) and outer granular zone (OGZ, <b><i>B</i></b>). Light micrographs were acquired at 10x (<i>left panels</i>) and 40x (<i>right panels</i>) magnification. (<b><i>C, D</i></b>) Percentage of dentate granule cells with different numbers of primary dendrites. GluN2A expression did not alter the number of cells with one (<i>black</i>), two (<i>grey</i>), and three or more (<i>white</i>) primary dendrites in IGZ (<b><i>C</i></b>) and OGZ (<b><i>D</i></b>) cells. Scale bar  = 100 µm (<i>left panels</i>), 25 µm (<i>right panels</i>) (<b><i>A, B</i></b>).</p

Altered dendritic morphology in IGZ dentate granule cells from GluN2A^−/− mice.

<p>(<b><i>A, D</i></b>) Total dendritic length was significantly decreased in GluN2A^−/− inner granular zone (IGZ) cells (<b><i>A</i></b>) and unaltered in GluN2A^−/− outer granular zone (OGZ) cells (<b><i>D</i></b>). <b><i>B, E,</i></b> Sholl analysis of IGZ (<b><i>B</i></b>) and OGZ (<b><i>E</i></b>) cells. A repeated measures ANOVA revealed a main effect of genotype in IGZ cells (<b><i>B</i></b>), with GluN2A^−/− IGZ cells having a lower number of dendrites per ring intersection from 80–160 µm from soma. No effect of genotype was seen in OGZ cells (<b><i>E</i></b>). (<b><i>C, F</i></b>) Branch order analysis of IGZ (<b><i>C</i></b>) and OGZ (<b><i>F</i></b>) cells. A repeated measures ANOVA revealed a main effect of genotype in IGZ cells (<b><i>C</i></b>), showing a significantly less number of third-order branches in GluN2A^−/− IGZ cells. OGZ cells did not show a main effect of genotype (<b><i>F</i></b>). For all graphs, WT: black; GluN2A^−/−: white. Data is represented as means ± SEM. * denotes statistical significant difference (<i>p</i><0.05).</p

Intact rate of differentiation in the adult dentate gyrus of GluN2A^−/− mice.

<p>(<b><i>A</i></b>) Representative images of dentate gyrus sections processed for NeuroD immunohistochemistry in wild-type (WT, <i>left panel</i>) and GluN2A^−/− (<i>right panel</i>) mice. (<b><i>B</i></b>) No change in the number of NeuroD-positive cells in the adult dentate gyrus of GluN2A^−/− mice, in comparison to wild-type littermates. For graph, WT: black; GluN2A^−/−: white. Data is represented as means ± SEM. Scale bar  = 100 µm (<b><i>A</i></b>).</p

IGZ dentate granule cells show an increase in spine density in adult GluN2A^−/− mice.

<p>(<b><i>A, D</i></b>) Representative tracings of inner granular zone (IGZ, <b><i>A</i></b>) and outer granular zone (OGZ, <b><i>D</i></b>) cells produced using Neurolucida. Three dendritic regions were chosen from both the middle molecular layer (MML) and outer molecular layer (OML) of the dentate gyrus. (<b><i>B, E</i></b>) Representative images of dendritic regions from wild-type (WT, <i>upper panel</i>) and GluN2A^−/− (<i>lower panel</i>) granule cells located in the IGZ (<b><i>B</i></b>), and OGZ (<b><i>E</i></b>). (<b><i>C, F</i></b><b>)</b> Spine density of IGZ (<b><i>C</i></b>) and OGZ (<b><i>F</i></b>) cells. An increase in spine density was observed in IGZ cells from GluN2A^−/− mice, but only in the middle molecular layer (<b><i>C</i></b>). No changes in spine density were seen in OGZ cells, in either region of the molecular layer (<b><i>F</i></b>). GCL =  Granular Cell Layer. Data is represented as means ± SEM. Scale bar  = 1 µm (<b>B, E</b>). * denotes statistical significant difference (<i>p</i><0.05).</p

Intact rate of cell proliferation in the adult dentate gyrus of GluN2A^−/− mice.

<p><b><i>A, C,</i></b> Representative images of dentate gyrus sections processed for Ki-67 (<b><i>A</i></b>) and PCNA (<b><i>C</i></b>) immunohistochemistry in both wild-type (WT, <i>left panels</i>) and GluN2A^−/− (<i>right panels</i>) mice. (<b><i>B, D</i></b>) No change in the number of Ki-67-positive cells (<b><i>B</i></b>) or PCNA-positive cells (<b><i>D</i></b>) in the adult dentate gyrus of GluN2A^−/− mice in comparison to wild-type littermates. For both graphs, WT: black; GluN2A^−/−: white. Data is represented as means ± SEM. Scale bar  = 100 µm (<b><i>A, C</i></b>).</p