Tabernanthine
Tabernanthine
Tabernanthine is a bitter, crystalline indole alkaloid associated primarily with Tabernanthe iboga (Apocynaceae). It occurs naturally with the related alkaloid ibogaine and is isomeric with ibogaine. The compound has mainly been investigated in experimental pharmacology, particularly in relation to central monoaminergic systems, cardiovascular smooth muscle, tremor, and drug self-administration.
Properties
- Natural source: Tabernanthe iboga.
- Chemical class: Indole alkaloid; bitter crystalline compound.
- Relationship to ibogaine: Tabernanthine is an isomer of ibogaine and occurs with it in the plant.
- Receptor pharmacology: It has been reported to show affinity for sigma-2 sites, broadly comparable to ibogaine in the cited experimental literature.
- Neuropharmacology: Laboratory studies have examined effects on brain catecholamine synthesis and elimination, brain serotonin changes during hypoxia, and catecholamine turnover.
- Addiction research: In animal experiments, tabernanthine persistently reduced cocaine- and morphine-self-administration. These findings are preclinical and should not be interpreted as evidence of established human efficacy.
- Peripheral pharmacology: Studies have examined its effects on calcium movements, catecholamine-stimulated contraction, and cardiovascular responses in isolated tissues and anesthetized rats.
- Tremor: Experimental evidence implicates benzodiazepine receptors in tabernanthine-induced tremor.
Pharmacological themes
Central nervous system
The available studies suggest that tabernanthine can influence several neurotransmitter-related processes. Reported areas of investigation include catecholamine synthesis and elimination, catecholamine turnover, and serotonin responses under hypoxic conditions. These effects may help explain why the compound has been explored in models of stimulant and opioid reinforcement, although the precise mechanisms and their relevance to humans remain uncertain.
Cardiovascular system
Tabernanthine has been studied in isolated vascular and cardiac preparations. The literature describes effects on calcium handling and on contractions stimulated by catecholamines such as noradrenaline. Animal studies have also examined peripheral cardiovascular effects of tabernanthine tartrate. These findings indicate that cardiovascular activity is an important safety consideration in any discussion of the compound.
Toxicology and limitations
The evidence base is predominantly in vitro and animal-based, with many studies dating from the late twentieth century. The findings cannot establish clinical effectiveness, appropriate dosing, or safety in humans. Potential neurological and cardiovascular effects—including tremor and altered vascular or cardiac contractility—warrant caution. Tabernanthine should not be treated as a self-directed treatment for addiction or any medical condition.
Articles/Studies
- Benzodiazepine receptors are involved in tabernanthine-induced tremor: in vitro and in vivo evidence.
- Effects of tabernanthine on calcium and catecholamine stimulated contractions of isolated vascular and cardiac muscle.
- The action of tabernanthine on noradrenaline-stimulated contractions and 45Ca movements in rat isolated vascular smooth muscle.
- Peripheral cardiovascular effects of tabernanthine tartrate in anaesthetized rats.
- Evidence for an activating effect of tabernanthine on rat brain catecholamine synthesis and elimination.
- Evidence for an antagonistic action of tabernanthine on hypoxia-induced changes in brain serotonin levels.
- A review of chemical agents in the pharmacotherapy of addiction.
- Effect of tabernanthine on the turnover time of brain catecholamines in normal and hypobaric hypoxic rats.