Dynorphin1-13: interaction with other opiate ligand bindings in vitro

Javier Garzón, Pilar Sánchez-Blázquez, John Gerhart, Horace H. Loh, Nancy M. Lee

Research output: Contribution to journalArticlepeer-review

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Dynorphin1-13 is a potent inhibitor of electrically-induced contractions in the guinea pig ileum, where it has the properties of κ-(ethylketocyclazocine) type opioids. In the brain, however, it has no analgesic potency, yet inhibits that induced by morphine. To gain further insight into its mechanism of action in the latter system, we tested its ability to complete for the binding of several opiates to brain membranes in vitro. Dynorphin1-13 inhibited the binding of all ligands examined, including dihydromorphine, d-Ala2-d-Leu5-enkephalin, ethylketacyclazocine (EKC) and naloxone. In all cases, it reduced the number of high affinity sites and, in the case of EKC, it also increased the Kd. We conclude that the mechanism of dynorphin inhibition is not simple rapidly reversible competition and is certainly not identical with respect to all opiate ligands.

Original languageEnglish (US)
Pages (from-to)392-396
Number of pages5
JournalBrain Research
Issue number2
StatePublished - Jun 8 1984


  • brain
  • d-Ala-d-Leu-enkephalin
  • dihydromorphine
  • dynorphin
  • ethylketocyclazocine
  • high affinity binding


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