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 language | English (US) |
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Pages (from-to) | 109-114 |
Number of pages | 6 |
Journal | Neuroreport |
Volume | 9 |
Issue number | 1 |
DOIs | |
State | Published - Jan 5 1998 |
Keywords
- μ-opioid receptor
- 12-OH Ibogamine
- Agonist
- Ibogaine
- Metabolite
ASJC Scopus subject areas
- Neuroscience(all)