Figure 4.

Stimulation of 5-HT₇R/G₁₂ signaling promotes spinogenesis in organotypic hippocampal slices. A, Organotypic slices from the hippocampus of a P5 mouse were treated with vehicle (H₂O, control), 5-CT (100 nm), or 5-CT plus SB-269970 (1 μm) at DIV2 for 4 d. The day before analysis, slices were transfected with GFP. A series of z-stacks were acquired for neurons expressing GFP. Scale bar, 5 μm. B, Three-dimensional reconstructions were performed by using the method described by Herzog et al. (2006). C, Bar graphs show the spine density calculated in control, 5-CT-treated, and 5-CT plus SB-269970-treated preparations. Data shown as mean ± SEM (n = 30). A statistically significant difference between values is indicated (***p < 0.001). D, Representative images of the hippocampal CA1 region from control and 5-CT-treated organotypic preparations stained with anti-synaptophysin (blue) and anti-AMPAR (red) antibodies. Scale bar, 50 μm. E, Larger magnifications of selected areas indicated in D. Scale bar, 5 μm. F, Bar graphs show synaptophysin, AMPAR, and VGAT intensity in 5-CT-treated hippocampal slides normalized to the control preparations (dashed line). Data shown as mean ± SEM. *p < 0.05.