Levels of zif268 and arc mRNA were analyzed by Q-RT-PCR. As shown in Fig. 4a (F = 99.345), b (F = 43.18), the levels of these genes decreased on days 1, 3, 7 and 15 after stimulation. The expression of c-Fos protein decreased at days 1 and 3 and increased at day 7 after stimulation (Fig. 4c, d, F = 11.4). c-Fos positive cells were labeled and counted as described in "Methods" section. As shown in Fig. 4e, f (F = 23.965), the number of c-Fos-positive cells in intruder mice decreased significantly at days 3 and 7 after stimulation compared with those in the control mice, and then increased to the same levels as those in the control mice at day 15 after stimulation.Fig. 4Response of mPFC to social defeat stress. a mRNA levels of zif268 in mPFC tissues from intruder mice decreased at days 1, 3, 7 and 15 after stimulation compared with the control mice, one way ANOVA with Tukey’s test was used, F = 99.345, **p < 0.01 compared with the control, n = 8. b mRNA levels of arc in mPFC tissues from intruder mice decreased at days 1, 3, 7 and 15 after stimulation compared with the control mice, one way ANOVA with Tukey’s test was used, F = 43.18, **p < 0.01 compared with the control, n = 8. c Representative Western blot image of c-Fos. d Statistical analysis of c-Fos expression, one way ANOVA with Tukey’s test was used, F = 11.4, *p < 0.05, compared with the control, n = 8. e The representative images of c-Fos staining in mPFC. Squares in the upper images indicate areas that are shown magnified in the bottom images. Blue arrows indicate c-fos-positive cells. f Cell counts in the mPFC, one way ANOVA with Tukey’s test was used, F = 23.965, *p < 0.05, **p < 0.01 compared with the control, n = 4