2 Hz EA Reduces Heroin Withdrawal-Induced Hyperalgesia and Heroin Relapse by Downregulating P2X3 Receptors in DRG Neurons

Abstract

Electroacupuncture (EA) has effective analgesic effects. Our previous study demonstrated that the upregulation of P2X3 receptors in the dorsal root ganglia (DRG) might participate in heroin withdrawal-induced hyperalgesia. e aim of this study is to further explore whether 2 Hz EA reduces heroin relapse associated with its analgesic effect and whether P2X3 receptors in the DRG are involved in this process. 2 Hz EA was adopted to treat the heroin SA rats in the present study. Heroin-seeking and pain sensitivity were evaluated. e expression of P2X3 receptors in the DRG was detected. Our results showed that compared with the control group, the reinstatement, thermal hyperalgesia, and mechanical allodynia of the heroin-addicted group were increased significantly. e expression of P2X3 receptors in the DRG was increased markedly. After being treated using 2 Hz EA, reinstatement was reduced, hyperalgesia was decreased, and the upregulated expression of P2X3 receptors in the DRG had decreased significantly compared to that in the heroin-addicted group. Consequently, our results indicated that 2 Hz EA was an effective method for treating heroin-induced hyperalgesia and helping prevent relapse, and the potential mechanism might be related to the downregulation of P2X3 receptor expression in the DRG.

Tribute to Prof. Geoffrey Burnstock: his contribution to acupuncture

“…Subsequently, AP research in the field of purinergic signalling started to flourish and a large set of data has been accumulated on changes in purine (ATP, adenosine) concentrations, both locally and in the CNS, induced by manual acupuncture, electroacupuncture, or moxibustion [12][13][14][15][16][17]. The participation of purinergic receptors (P1: A1, A2a, A2b, A3) [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34], (P2: P2X2, P2X3, P2X7, P2Y1, P2Y13) [35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52], and neuronal pathways bearing these receptors [53,54] has been confirmed in different AP-sensitive conditions (pain, inflammation, myocardial ischemia, obesity, cerebral ischemia). The functionalized acupuncture needle as a SERS (surfaceenhanced Raman spectroscopy)-active platform was developed for rapid and sensitive determination of ATP concentration [55], and led further support to the purinergic basis of AP.…”