Inverse agonist action of Leu-enkephalin at delta(2)-opioid receptors mediates spinal antianalgesia.

@article{Rady2001InverseAA,
  title={Inverse agonist action of Leu-enkephalin at delta(2)-opioid receptors mediates spinal antianalgesia.},
  author={Jodie J Rady and Blythe B. Holmes and Leon Fu Tseng and James M Fujimoto},
  journal={The Journal of pharmacology and experimental therapeutics},
  year={2001},
  volume={297 2},
  pages={582-9}
}
Dynorphin A(1-17) given intrathecally releases spinal cholecystokinin to produce an antianalgesic action against spinal morphine in the tail-flick test in CD-1 mice. The present study showed that following the cholecystokinin step, a delta(2)-opioid inverse agonist action of Leu-enkephalin (LE), was involved. Pretreatment with intrathecal LE antiserum eliminated dynorphin and cholecystokinin-8s antianalgesia. A small dose of LE intrathecally produced antianalgesia that like that from dynorphin… CONTINUE READING