Fig. 9

Overexpression of lipocalin 2 in the brain induces anxiety-like behaviors in the light and dark task. Single intracerebroventricular injection of recombinant lipocalin 2 protein (7 μL, 1 μg/mL) or vehicle in the brain of the mouse, and light and dark tasks were assessed after 6 days. A Representative heat maps for the activities of each group during the light–dark test. The frequency during the time spent in the light compartment (B), the latency to the first entry into the light compartment (C), or the cumulative time in the light compartment (D) were determined. The velocity traveled in the light compartment is measured in (E). Quantitative data are presented as mean ± SEM (n = 5 per group). The Student’s t-test was used to examine the significance of the mean. * p < 0.01, vs. the vehicle or control group. LCN2: lipocalin 2, NS: not significant, SEM: standard error of mean