Noribogaine stimulates naloxone-sensitive [35S]GTPγS binding

John P. Pablo, Deborah C. Mash

Research output: Contribution to journalArticle

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Abstract

NORIBOGAINE is formed in vivo by the O-demethylation of the indole alkaloid ibogaine. We report here that noribogaine acts as a full agonist at the μ-opioid receptor. Noribogaine-stimulated guanylyl 5'γ-[35S]thio]- triphosphate ([35S]GTPγS) was studied in rat thalamic membranes to measure activation of guanine nucleotide binding proteins (G-proteins) in the presence of excess GDP. Noribogaine caused a 170% increase above basal [35S]GTPγS binding at sub-micromolar effective concentrations (EC50) in a naloxone-sensitive manner, confirming that this effect was an opioid receptor-mediated process. The level of intrinsic activity for noribogaine in these assays was comparable to the full agonists DAMGO and morphine. In contrast, ibogaine had no significant effect on [35S]GTPγS binding over a similar concentration range. The efficacy of noribogaine as a full μ-opioid agonist may explain ibogaine's ability to block the acute signs of opiate withdrawal and its suppressive effects on morphine self-administration.

Original languageEnglish (US)
Pages (from-to)109-114
Number of pages6
JournalNeuroreport
Volume9
Issue number1
DOIs
StatePublished - Jan 5 1998

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Keywords

  • μ-opioid receptor
  • 12-OH Ibogamine
  • Agonist
  • Ibogaine
  • Metabolite

ASJC Scopus subject areas

  • Neuroscience(all)

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