Interaction of iodinated enkephalin analogues with opiate receptors

Richard J. Miller*, Kwen Jen Chang, Jeff Leighton, Pedro Cuatrecasas

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

53 Scopus citations


Radioiodinated derivatives of the metabolically stable enkephalin analogues, [DAla2,Leu5]- and [DAla2,DLeu5]-enkephalin, have been prepared. Such derivatives show sterospecific binding to receptors in brain homogenates and some neuroblastoma cell lines such as NG108-15 and N4TG1. The relative effects of levorphanol and dextrorphan and Na+ and Mn++ ions on enkephalin binding in brain and cells indicate that the iodinated derivatives are interacting with opiate receptors. Levorphanol is considerably more potent in displacing specifically bound enkephalin than dextrorphan. Sodium ions at physiological concentrations decrease enkephalin binding whereas manganese ions enhance it. Unlabelled monoiodo derivatives retain high potency in the guinea-pig ileum, mouse vas deferens and receptor binding assays. Unlabelled diiodo derivatives show far lower potency in these assays. It is concluded that radio-iodinated derivatives containing one iodine per molecule retain high affinity for the opiate receptor but diiodo derivatives do not.

Original languageEnglish (US)
Pages (from-to)379-387
Number of pages9
JournalLife Sciences
Issue number5
StatePublished - Feb 1978

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Pharmacology, Toxicology and Pharmaceutics(all)


Dive into the research topics of 'Interaction of iodinated enkephalin analogues with opiate receptors'. Together they form a unique fingerprint.

Cite this