Mu opioid receptor-containing neurons mediate electroacupuncture-produced anti-hyperalgesia in rats with hind paw inflammation

Previous studies showed that electroacupuncture (EA) significantly attenuates inflammatory hyperalgesia in a complete Freund's adjuvant (CFA)-induced inflammatory pain rat model. The present study demonstrates that pretreatment with Derm-sap, a selective toxin for neurons that contain mu opioid receptor (MOR), specifically decreases MOR and blocks EA anti-hyperalgesia. These data suggest that spinal MOR-containing neurons are involved in the processes by which EA produces anti-hyperalgesia.