Effect of acupuncture on Lipopolysaccharide-induced anxiety-like behavioral changes: involvement of serotonin system in dorsal Raphe nucleus

BACKGROUND: Acupuncture has been used as a common therapeutic tool in many disorders including anxiety and depression. Serotonin transporter (SERT) plays an important role in the pathology of anxiety and other mood disorders. The aim of this study was to evaluate the effects of acupuncture on lipopolysaccharide (LPS)-induced anxiety-like behaviors and SERT in the dorsal raphe nuclei (DRN). METHODS: Rats were given acupuncture at ST41 (Jiexi), LI11 (Quchi) or SI3 (Houxi) acupoint in LPS-treated rats. Anxiety-like behaviors of elevated plus maze (EPM) and open field test (OFT) were measured and expressions of SERT and/or c-Fos were also examined in the DRN using immunohistochemistry. RESULTS: The results showed that 1) acupuncture at ST41 acupoint, but neither LI11 nor SI3, significantly attenuated LPS-induced anxiety-like behaviors in EPM and OFT, 2) acupuncture at ST41 decreased SERT expression increased by LPS in the DRN. CONCLUSIONS: Our results suggest that acupuncture can ameliorate anxiety-like behaviors, possibly through regulation of SERT in the DRN.