Increased Hyperalgesia and Proinflammatory Cytokines in the Spinal Cord and Dorsal Root Ganglion After Surgery and/or Fentanyl Administration in Rats

The surgical plantar incision with or without perioperative fentanyl induced significant mechanical and thermal hyperalgesia, an increased expression of IL-1β, IL-6, TNF-α in the spinal cord and DRG, and activation of microglia in the spinal cord.