5_HT in the dorsal raphe nucleus is involved in the effects of 100_Hz electro_acupuncture on the pain_depression dyad in rats

Authors
Y_Y WU, Y_L JIANG, X_F HE, X_Y ZHAO, X_M SHAO, J SUN, Z SHEN, S_Y SHOU, J_J WEI, J_Y YE, S_S YAN, J-Q FANG

Lab
Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China

Journal
Experimental and Therapeutic Medicine

Abstract
The pain_depression dyad is becoming widespread in the clinic and is attracting increasing attention. A previous study by our group found that 100_Hz ectro_acupuncture (EA), but not 2_, 50_ and 2/100_Hz EA, was effective against the reserpine_induced pain_depression dyad. This finding is in contrast to the fact that low_frequency EA is commonly used to treat supraspinal_originating diseases. The present study aimed to investigate the mechanism underlying the effects of 100_Hz EA on the pain_depression dyad. Repeated reserpine injection was found to induce allodynia and depressive behaviors in rats. It decreased _hydroxytryptamine (5_HT) levels and immunoreactive expressions in the dorsal raphe nucleus (DRN). 100_Hz EA alleviated the pain_depression dyad and upregulated 5_HT in the DRN of reserpine_injected rats. Intracerebroventricular injection of para_chlorophenylalanine, an inhibitor of 5_HT resynthesis, suppressed the upregulation of 5_HT in the DRN by 100_Hz EA and partially counteracted the analgesic and anti_depressive effects of 100_Hz EA. The present study was the first to demonstrate that 5_HT in the DRN is involved in mediating the analgesic and anti_depressive effects of 100_Hz EA on the pain_depression dyad. This finding provided a scientific basis for high_frequency EA as a potential treatment for the pain_depression dyad.

BIOSEB Instruments Used:
Electronic Von Frey 4 (BIO-EVF4),Electronic Von Frey 5 with embedded camera (BIO-EVF5)