Noribogaine (12-hydroxyibogamine): a biologically active metabolite of the antiaddictive drug ibogaine.
Annals of the New York Academy of Sciences – September 01, 2000
Source: PubMed
Summary
A key metabolite of the anti-addiction drug ibogaine, noribogaine, persists longer in the body and may offer a safer alternative. Researchers explored noribogaine's activity in rats, comparing its effects to ibogaine on behavior, stress hormones, and brain serotonin. Noribogaine remarkably caused fewer tremors and less stress, yet increased serotonin more potently. This highlights noribogaine's potential as a more favorable therapeutic option.
Abstract
Ibogaine (IBO) is a plant-derived alkaloid that is being evaluated as a possible medication for substance use disorders. When administered peripherally to monkeys and humans, IBO is rapidly converted to an o-demethylated metabolite, 12-hydroxyibogamine (NORIBO). We have found in rats that peak blood levels of NORIBO can exceed those of the parent compound, and NORIBO persists in the bloodstream for at least 24 h. Surprisingly few studies have examined the in vivo biological activity of NORIBO. In the present series of experiments, we compared the effects of intravenous (i.v.) administration of IBO and NORIBO (1 and 10 mg/kg) on unconditioned behaviors, circulating stress hormones, and extracellular levels of dopamine (DA) and serotonin (5-HT) in the nucleus accumbens of male rats. IBO caused dose-related increases in tremors and forepaw treading, whereas NORIBO did not. Both IBO and NORIBO produced significant elevations in plasma corticosterone and prolactin, but IBO was more potent as a stimulator of corticosterone secretion. Neither drug affected extracellular DA levels in the nucleus accumbens. However, both IBO and NORIBO increased extracellular 5-HT levels, and NORIBO was more potent in this regard. The present data demonstrate that NORIBO is biologically active and undoubtedly contributes to the in vivo pharmacological profile of IBO in rats. Most importantly, NORIBO appears less likely to produce the adverse effects associated with IBO (i.e., tremors and stress-axis activation), suggesting that the metabolite may be a safer alternative for medication development.