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Evidence-Based Complementary and Alternative Medicine
Volume 2015, Article ID 452412, 11 pages
http://dx.doi.org/10.1155/2015/452412
Research Article

Possible Involvement of µ Opioid Receptor in the Antidepressant-Like Effect of Shuyu Formula in Restraint Stress-Induced Depression-Like Rats

1Department of Pharmacology, College of Basic Medicine, Shandong University of Traditional Chinese Medicine, Jinan 250355, China
2Key Laboratory for Classical Theory of Traditional Chinese Medicine of Education Ministry, Shandong University of Traditional Chinese Medicine, Jinan 250355, China

Received 15 October 2014; Revised 14 January 2015; Accepted 21 January 2015

Academic Editor: Filippo Maggi

Copyright © 2015 Fu-rong Wang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Recently μ opioid receptor (MOR) has been shown to be closely associated with depression. Here we investigated the action of Shuyu, a Chinese herbal prescription, on repeated restraint stress induced depression-like rats, with specific attention to the role of MOR and the related signal cascade. Our results showed that repeated restraint stress caused significant depressive-like behaviors, as evidenced by reduced body weight gain, prolonged duration of immobility in forced swimming test, and decreased number of square-crossings and rearings in open field test. The stress-induced depression-like behaviors were relieved by Shuyu, which was accompanied by decreased expression of MOR in hippocampus. Furthermore, Shuyu upregulated BDNF protein expression, restored the activity of CREB, and stimulated MEK and ERK phosphorylation in hippocampus of stressed rats. More importantly, MOR is involved in the effects of Shuyu on these depression-related signals, as they can be strengthened by MOR antagonist CTAP. Collectively, these data indicated that the antidepressant-like properties of Shuyu are associated with MOR and the corresponding CREB, BDNF, MEK, and ERK signal pathway. Our study supports clinical use of Shuyu as an effective treatment of depression and also suggests that MOR might be a target for treatment of depression and developing novel antidepressants.