Figure 4.

Effect of septal urocortin 2 on anxiety is dependent on stress. Effect of septal urocortin 2 (48 pmol) in ICR mice treated with no stress or 30 min of immobilization stress on the following: a, latency to enter the light side of the light–dark box (seconds); b, total time spent in the light side of the light–dark box (seconds); c, locomotion in the open field (total square entries); d, percentage time in the center of the open field; e, locomotion in the open field with a novel object (total square entries; and f, percentage time spent in the center with a novel object. Transitions in the light–dark box and percentage center entries in open-field and novel-object tests are not shown. This dose of urocortin 2 had no effect on anxiety-like behavior in the low-stress condition but significantly increased anxiety-like behavior compared with vehicle in the light–dark box, open-field, and novel-object tests when combined with 30 min of immobilization stress. There was no difference in locomotion between vehicle- and peptide-treated mice in the stress condition. Data are presented as mean ± SEM. **p < 0.01;***p < 0.001.