Figure 3

Social dominance was bidirectionally altered by stress and fluoxetine, and highly correlated with depressive phenotypes. (a) Schema of dominance tube test showing competition of two mice in a 30-cm cylindrical tube. The horizontal bar graph shows percentages of wins in the tube test. CON group (75%) showed higher win scores against the CRS group (25%). The CRS group (32%) showed lower win scores against CRS + FLU group (68%). The CON group (45%) showed about half wins against the CRS + FLU group (55%). Winning points were calculated by counting win number for each mouse, averaged and presented histogram. The winning points of the CRS group were significantly lower compared with those of the CON and CRS + FLU. CON (1.400 ± 0.2211, n = 10) vs CRS (0.500 ± 0.1667, n = 10), **p = 0.0044, Student’s t-test. CRS (0.7273 ± 0.2371, n = 10) vs CRS + FLU (1.400 ± 0.1633, n = 10), *p = 0.0336, Student’s t-test. CON (0.900 ± 0.2333, n = 10) vs CRS + FLU (1.000 ± 0.2582, n = 10), p = 0.7771, Student’s t-test. (b–e) High correlation of winning points with the FST (a negative linear regression, R² = 0.99, n = 30, ***p = 0.0002. Winning points were calculated by counting win number in the total of four matches for each mouse and averaged. (b) TST (a negative linear regression, R² = 0.78, n = 30, *p = 0.0455) (c), sociability (a positive linear regression, R² = 0.90, n = 27, *p = 0.0146) (d) and social novelty (a positive linear regression, R² = 0.94, n = 28, *p = 0.0066) (e) indicate strong correlation between social dominance and those depressive phenotypes. Data are shown as mean ± SEM.