Selective Protection of Benzomorphan Binding Sites Against Inactivation by N‐Ethylmaleimide. Evidence for k‐Opioid Receptors in Frog Brain

Jolanta Zawilska, Abel Lajtha, Anna Borsodi

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Abstract: Selective binding of [3H]bremazocine and [3H]‐ethylketocyclazocine to k‐opioid receptor sites in frog (Rana esculenta) brain membranes is irreversibly inactivated by the sulfhydryl group alkylating agent N‐ethylmale‐imide (NEM). Pretreatment of the membranes with k‐selective compounds [ethylketocyclazocine (EKC), dy‐norphin (1–13), or U‐50,488H] but not with [D‐Ala2,N‐Me‐Phe4,Gly5‐ol]enkephalin (DAGO; μ specific ligand) or [d‐Ala2,N‐Me‐Phe4,Gly5‐ol]enkephalin (DADLE; δ specific ligand) strongly protects the binding of the radioligands against NEM inactivation. These results provide more evidence for the existence of k‐opioid receptors in frog brain. The relatively high concentrations of NEM that are needed to decrease the specific binding of [3H]bremazocine together with the observation of an almost complete protection of its binding sites by NaCl suggest that bremazocine may act as an opioid antagonist in frog brain.

Original languageEnglish
Pages (from-to)736-739
Number of pages4
JournalJournal of neurochemistry
Volume51
Issue number3
DOIs
Publication statusPublished - Sep 1988

Keywords

  • Opioid receptor
  • k Subtype

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience

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