3 Results
3.1 The concentration of D-serine in NAc was decreased in depression susceptible mice
After a brief (10 minutes) daily exposure to a highly aggressive resident mouse for 14 days, the mice were divided into control group, depression susceptible group and depression unsusceptible group with 10 mice in each group according to the results of behavioral experiments (data not shown). Then the prefrontal cortex, amygdala and NAc of each group were extracted respectively. Finally, the average content of D-serine in three different brain regions was calculated by high performance liquid chromatography (HPLC). The results showed that there was no significant difference in D-serine content in the prefrontal cortex and amygdala of the control group, depression susceptible group and depression unsusceptible group. However, compared with the control group and the depression unsusceptible group, the content of D-serine in the NAc of depression susceptible group was significantly reduced (n = 10, P < 0.01 vs. control or unsusceptible; Figure 1A). The results showed that the concentration of D-serine in NAc was decreased in depression susceptible group.