Figure 4

CUS and chronic PS increase depressive-, anhedonic-, and anxiety-like behaviors. Mice were subjected to 28 days of daily CUS or chronic PS and examined for changes in behavior 7-10 days later. A one-way ANOVA was used to examine potential differences between groups in all tests. (A) For anhedonia, mice were given a 48 hr two-bottle (water or 2% sucrose) choice to determine whether CUS or chronic PS altered sucrose preference. Control mice showed a significantly greater preference for sucrose compared to CUS and chronic PS mice. To examine whether anxiety was modulated by stress, we employed the marble-burying test. (B) Control mice showed reduced anxiety-like behavior and buried fewer marbles in a 30 min session compared to mice subjected to CUS and chronic PS mice. Additionally, chronic PS mice buried significantly more marbles than CUS mice. In a test of depressive-like behavior (tail-suspension test), chronic PS mice were faster to immobility than control and CUS mice (C). Data are expressed as Mean ± SEM. of grams of% sucrose consumed (A), number of marbles buried (B), or latency (seconds) to immobility. Columns that do not share the same letter are significantly different (One-way ANOVA; p < 0.05). Sucrose preference (n = 6-9/group), tail suspension (n = 10-16/group), marble burying (n = 9-16/group).