Figure 2

Effect of chronic fluoxetine treatment on adult neurogenesis in 5-HT4R KO mice. (A) Experimental scheme. Mice were intraperitoneally (ip) injected with fluoxetine (Flx) at a dose of 22 mg/kg for 21 days and were administered BrdU 24 h after the last treatment (on day-22) at a dose of 150 mg/kg. Mice were sacrificed 2 h after the BrdU injection. (B) Immunohistochemical visualization of BrdU in the SGZ of the DG. Scale bar: 100 μm. Arrows represent BrdU-positive cells. (C) Quantification of BrdU-positive cells in the SGZ of the DG in WT mice and 5-HT4R KO mice. Data are expressed as the mean ± SEM (n = 4 or 5). Main effect of drug: P = 0.0023; main effect of genotype: P = 0.0107; interaction of drug and genotype: P = 0.0048; P values determined by two-way ANOVA. *** P < 0.001 and N.S, not significant for post hoc Bonferroni’s test, respectively, after two-way ANOVA. (D) Representative images of anti-doublecortin (DCX) immunohistochemistry in the DG. Scale bar: 100 μm. (E) Quantification of DCX-positive immature neurons in the DG of the WT mice and 5-HT4R KO mice. The number of DCX-positive cells in the DG is shown as the number of cells per square millimeter of DG area. Data are expressed as the mean ± SEM (n = 4 or 5). Main effect of drug: P = 0.0214; main effect of genotype: P = 0.1372; interaction of drug and genotype: P = 0.0032; P values determined by two-way ANOVA. ** P < 0.01 and N.S., not significant for post hoc Bonferroni’s test, respectively, after two-way ANOVA.