Fig. 4

The sucrose preference test at different time. The values are expressed as mean ± SD (n = 10/group). Compared with control group “*p < 0.05, **p < 0.01”. Compared with 0 mg venlafaxine group “^# p < 0.05, ^## p < 0.01”. Compared with 10 mg venlafaxine group “^& p < 0.05, ^&& p < 0.01”. On day 22, the sucrose preference in control was higher than the other three groups (all p < 0.01). On day 29, there was still significant difference between the 0 mg venlafaxine and control group (p < 0.01); compared with the 0 mg venlafaxine group, the sucrose preference was higher in the 10 mg venlafaxine (p < 0.01). On day 36, there was still significant difference between the 0 mg venlafaxine and 10 mg venlafaxine group (p < 0.01). On day 43, the sucrose preference was higher in the 10 mg venlafaxine compared with the 5 mg venlafaxine group (p < 0.01)