Ibogaine Acute Administration in Rats Promotes Wakefulness, Long-Lasting REM Sleep Suppression, and a Distinctive Motor Profile

Noribogaine acute administration in rats promotes wakefulness and suppresses REM sleep

Ibogaine is a potent atypical psychedelic that has gained considerable attention due to its antiaddictive and antidepressant properties in preclinical and clinical studies. Previous research from our group showed that ibogaine suppresses sleep and produces an altered wakefulness state, which resembles natural REM sleep. However, after systemic administration, ibogaine is rapidly metabolized to noribogaine, which also shows antiaddictive effects but with a distinct pharmacological profile, making this drug a promising therapeutic candidate. Therefore, we still ignore whether the sleep/wake alterations depend on ibogaine or its principal metabolite noribogaine. To answer this question, we conducted polysomnographic recordings in rats following the administration of pure noribogaine. Our results show that noribogaine promotes wakefulness while reducing slow-wave sleep and blocking REM sleep, similar to our previous results reported for ibogaine administration. Thus, we shed new evidence on the mechanisms by which iboga alkaloids work in the brain.

Urethane anaesthesia exhibits neurophysiological correlates of unconsciousness and is distinct from sleep

Urethane is a general anaesthetic widely used in animal research. The state of urethane anaesthesia is unique because it alternates between macroscopically distinct electrographic states: a slow-wave state that resembles non-rapid eye movement (NREM) sleep and an activated state with features of both REM sleep and wakefulness. Although it is assumed that urethane produces unconsciousness, this has been questioned because of states of cortical activation during drug exposure. Furthermore, the similarities and differences between urethane anaesthesia and physiological sleep are still unclear. In this study, we recorded the electroencephalogram (EEG) and electromyogram in chronically prepared rats during natural sleep-wake states and during urethane anaesthesia. We subsequently analysed the power, coherence, directed connectivity and complexity of brain oscillations and found that EEG under urethane anaesthesia has clear signatures of unconsciousness, with similarities to other general anaesthetics. In addition, the EEG profile under urethane is different in comparison with natural sleep states. These results suggest that consciousness is disrupted during urethane. Furthermore, despite similarities that have led others to conclude that urethane is a model of sleep, the electrocortical traits of depressed and activated states during urethane anaesthesia differ from physiological sleep states.

5-HT2A Receptor Knockout Mice Show Sex-Dependent Differences following Acute Noribogaine Administration

Noribogaine (noribo) is the primary metabolite from ibogaine, an atypical psychedelic alkaloid isolated from the root bark of the African shrub Tabernanthe iboga. The main objective of this study was to test the hypothesis that molecular, electrophysiological, and behavioral responses of noribo are mediated by the 5-HT2A receptor (5-HT2AR) in mice. In that regard, we used male and female, 5-HT2AR knockout (KO) and wild type (WT) mice injected with a single noribo dose (10 or 40 mg/kg; i.p.). After 30 min., locomotor activity was recorded followed by mRNA measurements by qPCR (immediate early genes; IEG, glutamate receptors, and 5-HT2AR levels) and electrophysiology recordings of layer V pyramidal neurons from the medial prefrontal cortex. Noribo 40 decreased locomotion in male, but not female WT. Sex and genotype differences were observed for IEG and glutamate receptor expression. Expression of 5-HT2AR mRNA increased in the mPFC of WT mice following Noribo 10 (males) or Noribo 40 (females). Patch-clamp recordings showed that Noribo 40 reduced the NMDA-mediated postsynaptic current density in mPFC pyramidal neurons only in male WT mice, but no effects were found for either KO males or females. Our results highlight that noribo produces sexually dimorphic effects while the genetic removal of 5HT2AR blunted noribo-mediated responses to NMDA synaptic transmission.

Main targets of ibogaine and noribogaine associated with its putative anti-addictive effects: A mechanistic overview

BACKGROUND

There is a growing interest in studying ibogaine (IBO) as a potential treatment for substance use disorders (SUDs). However, its clinical use has been hindered for mainly two reasons: First, the lack of randomized, controlled studies informing about its safety and efficacy. And second, IBO's mechanisms of action remain obscure. It has been challenging to elucidate a predominant mechanism of action responsible for its anti-addictive effects.

OBJECTIVE

To describe the main targets of IBO and its main metabolite, noribogaine (NOR), in relation to their putative anti-addictive effects, reviewing the updated literature available.

METHODS

A comprehensive search involving MEDLINE and Google Scholar was undertaken, selecting papers published until July 2022. The inclusion criteria were both theoretical and experimental studies about the pharmacology of IBO. Additional publications were identified in the references of the initial papers.

RESULTS

IBO and its main metabolite, NOR, can modulate several targets associated with SUDs. Instead of identifying key targets, the action of IBO should be understood as a complex modulation of multiple receptor systems, leading to potential synergies. The elucidation of IBO's pharmacology could be enhanced through the application of methodologies rooted in the polypharmacology paradigm. Such approaches possess the capability to describe multifaceted patterns within multi-target drugs.

CONCLUSION

IBO displays complex effects through multiple targets. The information detailed here should guide future research on both mechanistic and therapeutic studies.

Reactivity of the Iboga Skeleton: Oxidation Study of Ibogaine and Voacangine

The iboga alkaloids scaffold shows great potential as a pharmacophore in drug candidates for the treatment of neuropsychiatric disorders. Thus, the study of the reactivity of this type of motif is particularly useful for the generation of new analogs suitable for medicinal chemistry goals. In this article, we analyzed the oxidation pattern of ibogaine and voacangine using dioxygen, peroxo compounds, and iodine as oxidizing agents. Special focus was placed on the study of the regio- and stereochemistry of the oxidation processes according to the oxidative agent and starting material. We found that the C16-carboxymethyl ester present in voacangine stabilizes the whole molecule toward oxidation in comparison to ibogaine, especially in the indole ring, where 7-hydroxy- or 7-peroxy-indolenines can be obtained as oxidation products. Nevertheless, the ester moiety enhances the reactivity of the isoquinuclidinic nitrogen to afford C3-oxidized products through a regioselective iminium formation. This differential reactivity between ibogaine and voacangine was rationalized using computational DFT calculations. In addition, using qualitative and quantitative NMR experiments combined with theoretical calculations, the absolute stereochemistry at C7 in the 7-hydroxyindolenine of voacangine was revised to be S, which corrects previous reports proposing an R configuration.

Sleep/wake changes in perturbational complexity in rats and mice

In humans, the level of consciousness is assessed by quantifying the spatiotemporal complexity of cortical responses using Perturbational Complexity Index (PCI) and related PCIst (st, state transitions). Here we validate PCIst in freely moving rats and mice by showing that it is lower in NREM sleep and slow wave anesthesia than in wake or REM sleep, as in humans. We then show that (1) low PCIst is associated with the occurrence of an OFF period of neuronal silence; (2) stimulation of deep, but not superficial, cortical layers leads to reliable PCIst changes across sleep/wake and anesthesia; (3) consistent PCIst changes are independent of which single area is being stimulated or recorded, except for recordings in mouse prefrontal cortex. These experiments show that PCIst can reliably measure vigilance states in unresponsive animals and support the hypothesis that it is low when an OFF period disrupts causal interactions in cortical networks.

"A sense of the bigger picture:" A qualitative analysis of follow-up interviews with people with bipolar disorder who self-reported psilocybin use

OBJECTIVES

People with bipolar disorder (BD) spend more time depressed than manic/hypomanic, and depression is associated with greater impairments in psychosocial functioning and quality of life than mania/hypomania. Emerging evidence suggests psilocybin, the psychoactive compound in "magic mushrooms," is a promising treatment for unipolar depression. Clinical trials of psilocybin therapy have excluded people with BD as a precaution against possible adverse effects (e.g., mania). Our study centered the experiences of adults living with BD who consumed psilocybin-containing mushrooms, and aimed to (1) understand its subjective impacts on BD symptoms, (2) deepen understanding of Phase I survey results, and (3) elucidate specific contextual factors associated with adverse reactions in naturalistic settings.

METHODS

Following an international survey (Phase I), follow-up interviews were conducted with 15 respondents (Phase II) to further understand psilocybin use among adults with BD. As part of a larger mixed-methods explanatory sequential design study, reflexive thematic analysis was used to elaborate findings.

RESULTS

Three major themes containing sub-themes were developed. (1) Mental Health Improvements: (1.1) decreased impact and severity of depression, (1.2) increased emotion processing, (1.3) development of new perspectives, and (1.4) greater relaxation and sleep. (2) Undesired Mental Health Impacts: (2.1) changes in sleep, (2.2) increased mania severity, (2.3) hospitalization, and (2.4) distressing sensory experiences. (3) Salient Contextual Factors for psilocybin use included: (3.1) poly-substance use and psilocybin dose, (3.2) solo versus social experiences, and (3.3) pre-psilocybin sleep deprivation.

CONCLUSION

Our findings demonstrate both benefits and risks of psilocybin use in this population. Carefully designed clinical trials focused on safety and preliminary efficacy are warranted.

Efficient Access to the Iboga Skeleton: Optimized Procedure to Obtain Voacangine from Voacanga africana Root Bark

Iboga alkaloids are a group of monoterpenoid indole alkaloids with promising and intriguing biological activities. Ibogaine is the representative member of the series and has become widely known as a potent atypical psychedelic with promising effects to treat substance use disorder. Nowadays, an efficient and scalable enantioselective total synthesis of ibogaine and related iboga alkaloids is still lacking, so direct extraction from natural sources or semi-synthetic schemes are the methods of choice to obtain them in a preparative scale. In particular, ibogaine can be obtained either by a low yielding direct isolation from Tabernanthe iboga or using a semi-synthetic procedure from voacangine, an iboga alkaloid occurring in a higher yield in the root bark of Voacanga africana. In this work, we describe an optimized process to obtain voacangine from V. africana root bark as a precursor of the iboga scaffold. Using a direct acetone-based extraction procedure (0.5 kg of root bark), voacangine was isolated in ∼0.8% of root bark dried weight, while the major alkaloids isolated from the bark were identified as iboga-vobasinyl dimers (∼3.7%) such as voacamine and voacamidine. Since these alkaloids contain the voacangine moiety in their structure, the cleavage of the dimers was further optimized, affording an extra amount of voacangine in ∼50% isolated molar yield. In this manner, the total amount of voacangine obtained by application of the whole procedure to the plant material (extraction and dimer cleavage) could almost duplicate the content originally found in the root bark.

A narrative review of the pharmacological, cultural and psychological literature on ibogaine

Ibogaine is a psychoactive alkaloid contained in the West African plant Tabernanthe iboga. Although preliminary, evidence suggests that ibogaine could be effective in the treatment of certain substance use disorders, specifically opioid use disorder. This narrative review concentrated on the pharmacological, cultural and psychological aspects of ibogaine that contribute to its reputed effectiveness with a specific focus on the ibogaine state of consciousness. Although the exact pharmacological mechanisms for ibogaine are still speculative, the literature highlighted its role as an NMDA antagonist in the effective treatment of substance use disorders. The cultural aspects associated with the use of ibogaine pose questions around the worldview of participants as experienced in the traditional and western contexts, which future research should clarify. From a psychological perspective, the theory that the ibogaine state of consciousness resembles REM sleep is questionable due to evidence that indicated ibogaine supressed REM sleep, and contradictory evidence in relation to learning and memory. The suggested classification of the ibogaine experience as oneirophrenic also seems inadequate as it only describes the first phase of the ibogaine experience. The ibogaine experience does however present characteristics consistent with holotropic states of consciousness, and future research could focus on exploring and potentially classifying the state of consciousness induced by ibogaine as holotropic.

EEG Gamma Band Alterations and REM-like Traits Underpin the Acute Effect of the Atypical Psychedelic Ibogaine in the Rat

Ibogaine is a psychedelic alkaloid that has attracted large scientific interest because of its antiaddictive properties in observational studies in humans as well as in animal models. Its subjective effect has been described as intense, vivid dream-like experiences occurring while awake; hence, ibogaine is often referred to as an oneirogenic psychedelic. While this unique dream-like profile has been hypothesized to aid the antiaddictive effects, the electrophysiological signatures of this psychedelic state remain unknown. We previously showed in rats that ibogaine promotes a waking state with abnormal motor behavior along with a decrease in NREM and REM sleep. Here, we performed an in-depth analysis of the intracranial electroencephalogram during "ibogaine wakefulness". We found that ibogaine induces gamma oscillations that, despite having larger power than control levels, are less coherent and less complex. Further analysis revealed that this profile of gamma activity compares to that of natural REM sleep. Thus, our results provide novel biological evidence for the association between the psychedelic state and REM sleep, contributing to the understanding of the brain mechanisms associated with the oneirogenic psychedelic effect of ibogaine.

Natural Cannabinoids as Templates for Sleep Disturbances Treatments

The sleep-wake cycle is a complex composition of specific physiological and behavioral characteristics. In addition, neuroanatomical, neurochemical and molecular systems exerts influences in the modulation of the sleep-wake cycle. Moreover, homeostatic and circadian mechanisms interact to control the waking or sleeping states. As many other behaviors, sleep also develops pathological features that include several signs and symptoms corresponding to medical conditions known as sleep disorders.In addition to the neurobiological mechanisms modulating sleep, external elements also influence the sleep-wake cycle, including the use of Cannabis sativa (C. sativa). In this regard, and over the last decades, the interest of studying the pharmacology of Δ⁹-tetrahydrocannabinol (Δ⁹-THC), the principal psychoactive constituent of C. sativa, has been addressed. Moreover, in recent years, the focus of scientific interest has moved on to studying the second plant constituent with non-psychotropic pharmacological properties: Cannabidiol (CBD).The pharmacological and pharmaceutical interest of CBD has been focus of attention due to the accumulating body of evidence regarding the positive outcomes of using CBD for the treatment of several health issues, such as psychiatric and neurodegenerative disorders, epilepsy, etc. Since the most prominent sleep disruptions include excessive daytime sleepiness (EDS), current treatments include the use of drugs such as stimulants of antidepressants. Notwithstanding, side effects are commonly reported among the patients under prescription of these compounds. Thus, the search of novelty therapeutical approaches aimed to treat ESD may consider the use of cannabinoid-derived compounds, such as CBD. In this chapter, we will show experimental evidence regarding the potential role of CBD as a wake-inducing compound aimed to manage EDS.

A Single Administration of the Atypical Psychedelic Ibogaine or Its Metabolite Noribogaine Induces an Antidepressant-Like Effect in Rats

Anecdotal reports and open-label case studies in humans indicated that the psychedelic alkaloid ibogaine exerts profound antiaddictive effects. Ample preclinical evidence demonstrated the efficacy of ibogaine, and its main metabolite, noribogaine, in substance-use-disorder rodent models. In contrast to addiction research, depression-relevant effects of ibogaine or noribogaine in rodents have not been previously examined. We have recently reported that the acute ibogaine administration induced a long-term increase of brain-derived neurotrophic factor mRNA levels in the rat prefrontal cortex, which led us to hypothesize that ibogaine may elicit antidepressant-like effects in rats. Accordingly, we characterized behavioral effects (dose- and time-dependence) induced by the acute ibogaine and noribogaine administration in rats using the forced swim test (FST, 20 and 40 mg/kg i.p., single injection for each dose). We also examined the correlation between plasma and brain concentrations of ibogaine and noribogaine and the elicited behavioral response. We found that ibogaine and noribogaine induced a dose- and time-dependent antidepressant-like effect without significant changes of animal locomotor activity. Noribogaine's FST effect was short-lived (30 min) and correlated with high brain concentrations (estimated >8 μM of free drug), while the ibogaine's antidepressant-like effect was significant at 3 h. At this time point, both ibogaine and noribogaine were present in rat brain at concentrations that cannot produce the same behavioral outcome on their own (ibogaine ∼0.5 μM, noribogaine ∼2.5 μM). Our data suggests a polypharmacological mechanism underpinning the antidepressant-like effects of ibogaine and noribogaine.

Ibogaine Administration Modifies GDNF and BDNF Expression in Brain Regions Involved in Mesocorticolimbic and Nigral Dopaminergic Circuits

Ibogaine is an atypical psychedelic alkaloid, which has been subject of research due to its reported ability to attenuate drug-seeking behavior. Recent work has suggested that ibogaine effects on alcohol self-administration in rats are related to the release of Glial cell Derived Neurotrophic Factor (GDNF) in the Ventral Tegmental Area (VTA), a mesencephalic region which hosts the soma of dopaminergic neurons. Although previous reports have shown ibogaine’s ability to induce GDNF expression in rat midbrain, there are no studies addressing its effect on the expression of GDNF and other neurotrophic factors (NFs) such as Brain Derived Neurotrophic Factor (BDNF) or Nerve Growth Factor (NGF) in distinct brain regions containing dopaminergic neurons. In this work, we examined the effect of ibogaine acute administration on the expression of these NFs in the VTA, Prefrontal Cortex (PFC), Nucleus Accumbens (NAcc) and the Substantia Nigra (SN). Rats were i.p. treated with ibogaine 20 mg/kg (I₂₀), 40 mg/kg (I₄₀) or vehicle, and NFs expression was analyzed after 3 and 24 h. At 24 h an increase of the expression of the NFs transcripts was observed in a site and dose dependent manner. Only for I₄₀, GDNF was selectively upregulated in the VTA and SN. Both doses elicited a large increase in the expression of BDNF transcripts in the NAcc, SN and PFC, while in the VTA a significant effect was found only for I₄₀. Finally, NGF mRNA was upregulated in all regions after I₄₀, while I₂₀ showed a selective upregulation in PFC and VTA. Regarding protein levels, an increase of GDNF was observed in the VTA only for I₄₀ but no significant increase for BDNF was found in all the studied areas. Interestingly, an increase of proBDNF was detected in the NAcc for both doses. These results show for the first time a selective increase of GDNF specifically in the VTA for I₄₀ but not for I₂₀ after 24 h of administration, which agrees with the effective dose found in previous self-administration studies in rodents. Further research is needed to understand the contribution of these changes to ibogaine’s ability to attenuate drug-seeking behavior.

A case report SPECT study and theoretical rationale for the sequential administration of ibogaine and 5-MeO-DMT in the treatment of alcohol use disorder

Ibogaine is a plant-derived alkaloid and dissociative psychedelic that demonstrates anti-addictive properties with several substances of abuse, including alcohol. 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) is a naturally occurring psychedelic known to occasion potent mystical-type experiences and also demonstrates anti-addictive properties. The potential therapeutic effects of both compounds in treating alcohol use disorder require further investigation and there are no published human neuroimaging findings of either treatment to date. We present the case of a 31-year-old male military veteran with moderate alcohol use disorder who sought treatment at an inpatient clinic in Mexico that utilized a sequential protocol with ibogaine hydrochloride (1550mg, 17.9mg/kg) on day 1, followed by vaporized 5-MeO-DMT (bufotoxin source 50mg, estimated 5-MeO-DMT content, 5-7mg) on day 3. The patient received SPECT neuroimaging that included a resting-state protocol before, and 3 days after completion of the program. During the patient's ibogaine treatment, he experienced dream-like visions that included content pertaining to his alcohol use and resolution of past developmental traumas. He described his treatment with 5-MeO-DMT as a peak transformational and spiritual breakthrough. On post-treatment SPECT neuroimaging, increases in brain perfusion were noted in bilateral caudate nuclei, left putamen, right insula, as well as temporal, occipital, and cerebellar regions compared to the patient's baseline scan. The patient reported improvement in mood, cessation of alcohol use, and reduced cravings at 5 days post-treatment, effects which were sustained at 1 month, with a partial return to mild alcohol use at 2 months. In this case, serial administration of ibogaine and 5-MeO-DMT resulted in increased perfusion in multiple brain regions broadly associated with alcohol use disorders and known pharmacology of both compounds, which coincided with a short-term therapeutic outcome. We present theoretical considerations regarding the potential of both psychedelic medicines in treating alcohol use disorders in the context of these isolated findings, and areas for future investigation.