Effects of E2 administration on anxiety phenotypes in the light-dark box test.

Mice were placed in the test apparatus consisting of a black plastic box (dark box) and a transparent plastic box (light box) connected by a small tunnel that allowed mice to move freely between the compartments. The number of traverses of the tunnel and the time spent in the light box during 10 min were analyzed (A). The time spent in the light box is considered to be an index of the level of anxiety and the number of tunnel traverses is an index of general motor activity (B). Results are shown as Turkey style box plots with data falling outside the lower and upper quartiles plotted as circles. Values are the mean ± SE (control, n = 13; OVX-HF, n = 17; E2-SC, n = 11; E2-ICV, n = 10). P values were determined by the two-tailed Kruskal Wallis H-test with the Mann-Whitney U-test. *P†p<0.05 vs. the OVX-HF group.