Figure 1.

A schematic CIS paradigm and the result of behavioral assessments. (A) A schematic drawing of CIS (2 h per day for 15 days) and behavioral assessments: sucrose preference test (SPT) and forced swim test (FST). After behavioral assessments, the experimental animals were killed by decapitation (DC) on day 26 for Q-PCR analysis. On the day before FST, mice were adapted to swimming with a pre-swimming (P) session. The body weight (B) and food intake (C) were measured every other day during experimentation except for during the SPT period. The significance of the mean difference between the stressed (STR, n = 10) and control (CTL, n = 10) groups was measured with a t-test on each day. The STR group showed body weight reduction over the 15-day CIS period. Significant mean differences in food intake were only found on days 2, 14, and 16 after the experiment began. Sucrose preference of the STR group was significantly decreased (D), and immobility duration of the STR group increased (E) compared with CTL, indicating that STR mice were more depressed than CTL mice. Data are the means ± SEM. *, P < 0.05; **, P < 0.01 between CTL and STR groups