Effects of stress of different duration on depression-like behavior and expression of CB1 and GluA1 in medial prefrontal cortex of rats

Objective: To explore the changes of cannabinoid receptor (CB1) and AMPA receptor subunit GluA1 in the medial prefrontal cortex (mPFC) of depression model rats induced by chronic unpredictable mild stress (CUMS). Methods: 30 rats were randomly divided into three groups. The three-week model group was given a three-week CUMS model, the four-week model group was given a four-week CUMS model, and the control group was given no treatment. The behavior of rats were detected in each group, and the expression of CB1 and GluA1 protein in synaptosomes in mPFC brain region was detected by Western blot. Results: Compared with the control group, the surcose preference decreased, the feeding latency increased in the novel inhibition feeding test, and the immobility time increased in the forced swimming test in the four-week model group. However, after three weeks of CUMS, there was no obvious change in the behavior of rats compared with the control group, suggesting that four-week model of CUMS was successful. CUMS can reduce the expression level of CB1 and GluA1 protein in synaptosomes of mPFC brain area in four-week model group (P<0.05), but there was no significant difference between three-week model group and control group. Conclusion: Four-week CUMS was more likely to lead to depressive-like behavior in rats, which may be closely related to the expression of CB1 and GluA1 in mPFC.