Opiates are currently the mainstay for treatment of moderate to severe pain. However,
prolonged administration of opiates has been reported to elicit hyperalgesia in animals, and
examples of opiate-induced hyperalgesia have been reported in humans as well. Despite
the potential clinical significance of such opiate-induced actions, the mechanisms of opiate-
induced hypersensitivity remain unknown. The transient receptor potential vanilloid1
(TRPV1) receptor, a molecular sensor of noxious heat, acts as an integrator of multiple forms …