The psychedelic call: analysis of Australian Poisons Information Centre calls associated with classic psychedelics

INTRODUCTION

The global use of certain classical psychedelics has increased in recent years, but little is known about their spectrum of toxicity within Australia. We aim to describe calls to New South Wales Poisons Information Centre relating to exposures to classical psychedelics including lysergic acid diethylamide, psilocybin, N,N-dimethyltryptamine, ayahuasca, mescaline and ibogaine.

METHODS

This is a retrospective observational study of calls to New South Wales Poisons Information Centre between January 2014 and December 2022. We identified exposures to classical psychedelics within New South Wales Poisons Information Centre database and measured the annual number of exposures, source of call (hospital, health care worker, member of the public), co-ingested substances, clinical features and advice given.

RESULTS

There were 737 calls related to relevant psychedelic exposures; 352 (47.8 per cent) to lysergic acid diethylamide, 347 (47.0 per cent) to psilocybin, 28 (3.8 per cent) to N,N-dimethyltryptamine, 4 (0.5 per cent) to ayahuasca, 4 (0.5 per cent) to mescaline and 2 (0.3 per cent) to ibogaine. Cases were predominantly male (77.2 per cent) and aged between 20 and 74 years (65.6 per cent). Psychedelic calls more than doubled from 45 in 2014 to 105 in 2022 and 625 (85 per cent) of all calls were either from or referred to hospital. Co-ingestion of psychedelics with another substance occurred in 249 (33.8 per cent) of calls and the most frequent clinical features related to single substance psychedelic exposures were hallucinations (27.6 per cent), gastrointestinal symptoms (21.7 per cent) and tachycardia (18.1 per cent). Seizures occurred in 2.9 per cent of single substance psychedelic exposures.

DISCUSSION

Increasing incidence of psychedelic exposure calls, including those reporting significant toxicity, likely reflects increasing community use. This may in part be driven by increasing interest in psychedelic assisted psychotherapy trials subsequently increasing public awareness.

CONCLUSION

Relatively high poisoning severity contrasts with safety within clinical trials of psychedelic assisted psychotherapy that may relate to the uncontrolled nature of community use which is mitigated within clinical trial environments. Education about safe use may be useful.

The pharmacokinetics and pharmacodynamics of ibogaine in opioid use disorder patients

OBJECTIVE

Ibogaine is a hallucinogenic drug that may be used to treat opioid use disorder (OUD). The relationships between pharmacokinetics (PKs) of ibogaine and its metabolites and their clinical effects on side effects and opioid withdrawal severity are unknown. We aimed to study these relationships in patients with OUD undergoing detoxification supported by ibogaine.

METHODS

The study was performed in 14 subjects with OUD. They received a single dose of 10mg/kg ibogaine hydrochloride. Plasma PKs of ibogaine, noribogaine, and noribogaine glucuronide were obtained during 24 h. Cytochrome P450 isoenzyme 2D6 (CYP2D6) genotyping was performed. The PKs were analyzed by means of nonlinear mixed effects modeling and related with corrected QT interval (QTc) prolongation, cerebellar ataxia, and opioid withdrawal severity.

RESULTS

The PK of ibogaine were highly variable and significantly correlated to CYP2D6 genotype (p < 0.001). The basic clearance of ibogaine (at a CYP2D6 activity score (AS) of 0) was 0.82 L/h. This increased with 30.7 L/h for every point of AS. The relation between ibogaine plasma concentrations and QTc was best described by a sigmoid Emax model. Spearman correlations were significant (p < 0.03) for ibogaine but not noribogaine with QTc (p = 0.109) and cerebellar effects (p = 0.668); neither correlated with the severity of opioid withdrawal symptoms.

CONCLUSIONS

The clearance of ibogaine is strongly related to CYPD2D6 genotype. Ibogaine cardiac side effects (QTc time) and cerebellar effects are most likely more driven by ibogaine rather than noribogaine. Future studies should aim at exploring lower doses and/or applying individualized dosing based on CYP2D6 genotype.

Commentary: Evidence-Informed Recommendation to Achieve Approximate Parity in the Allowed Number of Doses for Common Psychedelics

In recent years, policymakers have proposed and implemented regulatory changes promoting the deprioritization, decriminalization, or state-level legalization of one or more psychedelic substances, usually referencing data from clinical trials as reasons to support liberalizing drug control policies. As psychedelic policies continue to be drafted, personal possession limits may be considered for inclusion in those regulations. If "allowable amount" limits are to be written into law to set personal possession limits, then such amounts should be more consistently related to psychedelic doses found to be safe and efficacious in clinical trials, existing data on moderate-high doses commonly used in various naturalistic settings, and the few studies that estimate psychedelic dose equivalence based on the intensity of subjective effects. In this commentary, we provide an evidence-informed table of typical moderate-high doses for seven commonly used psychedelic substances. These estimates of comparable moderate-high doses can be used to inform "allowable amount" values for psychedelic substances. When such limits are written into legislation, the adoption of evidence-informed comparable limits akin to those presented here would be an important first step toward ensuring greater parity and consistency in drug policy, relative to limits that have little or no scientific basis.

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.

Psychedelic Treatments for Substance Use Disorder and Substance Misuse: A Mixed Methods Systematic Review

Renewed interest in psychedelic substances in the 21st century has seen the exploration of psychedelic treatments for various psychiatric disorders including substance use disorder (SUD). This review aimed to assess the effectiveness of psychedelic treatments for people with SUD and those falling below diagnostic thresholds (i.e. substance misuse). We systematically searched 11 databases, trial registries, and psychedelic organization websites for empirical studies examining adults undergoing psychedelic treatment for SUD or substance misuse, published in the English language, between 2000 and 2021. Seven studies investigating treatment using psilocybin, ibogaine, and ayahuasca, alone or adjunct with psychotherapy reported across 10 papers were included. Measures of abstinence, substance use, psychological and psychosocial outcomes, craving, and withdrawal reported positive results, however, this data was scarce among studies examining a wide range of addictions including opioid, nicotine, alcohol, cocaine and unspecified substance. The qualitative synthesis from three studies described subjective experience of psychedelic-assisted treatments enhanced self-awareness, insight, and confidence. At present, there is no sufficient research evidence to suggest effectiveness of any of the psychedelics on any specific substance use disorder or substance misuse. Further research using rigorous effectiveness evaluation methods with larger sample sizes and longer-term follow-up is required.

Open-label study of consecutive ibogaine and 5-MeO-DMT assisted-therapy for trauma-exposed male Special Operations Forces Veterans: prospective data from a clinical program in Mexico

Background: Research in psychedelic medicine has focused primarily on civilian populations. Further study is needed to understand whether these treatments are effective for Veteran populations.Objectives: Here, we examine the effectiveness of psychedelic-assisted therapy among trauma-exposed Special Operations Forces Veterans (SOFV) seeking treatment for cognitive and mental health problems in Mexico.Methods: Data were collected from an ibogaine and 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) clinical treatment program for SOFV with a history of trauma exposure. This clinical program collects prospective clinical program evaluation data, such as background characteristics, symptom severity, functioning (e.g., satisfaction with life, posttraumatic stress disorder symptoms, depression symptoms, anxiety symptoms, sleep disturbance, psychological flexibility, disability in functioning, cognitive functioning, neurobehavioral symptoms, anger, suicidal ideation), and substance persisting/enduring effects through online surveys at four timepoints (baseline/pre-treatment, one-, three-, and six-months after treatment).Results: The majority of the sample (n = 86; Mean Age = 42.88, SD = 7.88) were Caucasian (87.2%), non-Hispanic (89.5%), and males (100%). There were significant and large improvements in self-reported PTSD symptoms (p < .001, d = .414), depression (p < .001, d = .275), anxiety (p < .001, d = .276), insomnia severity (p < .001, d = .351), and post-concussive symptoms (p < .001, d = .389) as well as self-reported satisfaction with life (p < .001, d = .371), psychological flexibility (p < .001, d = .313) and cognitive functioning (p < .001, d = .265) from baseline to one-month follow-up.Conclusions: Data suggest combined ibogaine and 5-MeO-DMT assisted therapy has potential to provide rapid and robust changes in mental health functioning with a signal of durable therapeutic effects up to 6-months. Future research in controlled settings is warranted.

Case report: Ibogaine reduced severe neuropathic pain associated with a case of brachial plexus nerve root avulsion

Brachial plexus nerve root avulsion results from complete separation of the nerve root from the spinal cord and is one of the most challenging types of neuropathic pain, coinciding with motor, sensory and autonomic deficits. The severe pain and typical impossibility of root reattachment often leads to requests for amputation. Ibogaine is an indole alkaloid producing psychoactive effects through reported actions upon multiple neurotransmitter systems, including NMDA, κ- and µ-opioid receptors and σ2 receptor sites, along with stimulation of neurotrophic factors GDNF and BDNF. In this case report we describe a 53-year-old male with two decades of severe intractable pain due to brachial plexus nerve root avulsion from vehicular trauma who was successfully treated with both high dose inpatient and low dose outpatient administrations of ibogaine. Though promising for future study, the adverse effects of high dose ibogaine administrations may limit tolerability of this saturation protocol to the most refractory cases.

Beyond Psilocybin: Reviewing the Therapeutic Potential of Other Serotonergic Psychedelics in Mental and Substance Use Disorders

There has been a resurgence of interest in the use of psychedelic therapies for several mental and substance use disorders. Psilocybin, a "classic" serotonergic psychedelic, has emerged as one of the primary compounds of interest in clinical research. While research on psilocybin's potential mental health benefits has grown, data on the safety and efficacy of other serotonergic psychedelics remain limited. A comprehensive scoping review on the use of mescaline, ibogaine, ayahuasca, N,N-dimethyltryptamine (DMT), and lysergic acid diethylamide (LSD) in the treatment of mental and substance disorders was conducted. Independent reviewers screened titles, abstracts, and full texts and conducted data extraction. Seventy-seven studies met the inclusion criteria. There were 43 studies of LSD, 24 studies of ayahuasca, 5 studies of DMT, 5 studies of ibogaine, and 5 studies of mescaline. Commonly reported benefits included improved mood and anxiety symptoms, improved insight, reduced substance use, improved relationships, and decreased vegetative symptoms. Commonly reported adverse effects were psychological, neurological, physical, and gastrointestinal in nature. Serious adverse events (homicide and suicide) were reported in published studies of LSD. In conclusion, there is only low-level evidence to support the safety and efficacy of non-psilocybin serotonergic psychedelics in individuals with mental and substance use disorders.

Hallucinogenic potential: a review of psychoplastogens for the treatment of opioid use disorder

The United States is entering its fourth decade of the opioid epidemic with no clear end in sight. At the center of the epidemic is an increase in opioid use disorder (OUD), a complex condition encompassing physical addiction, psychological comorbidities, and socioeconomic and legal travails associated with the misuse and abuse of opioids. Existing behavioral and medication-assisted therapies show limited efficacy as they are hampered by lack of access, strict regimens, and failure to fully address the non-pharmacological aspects of the disease. A growing body of research has indicated the potential of hallucinogens to efficaciously and expeditiously treat addictions, including OUD, by a novel combination of pharmacology, neuroplasticity, and psychological mechanisms. Nonetheless, research into these compounds has been hindered due to legal, social, and safety concerns. This review will examine the preclinical and clinical evidence that psychoplastogens, such as ibogaine, ketamine, and classic psychedelics, may offer a unique, holistic alternative for the treatment of OUD while acknowledging that further research is needed to establish long-term efficacy along with proper safety and ethical guidelines.

Psychoactive plant derivatives (ayahuasca, ibogaine, kratom) and their application in opioid withdrawal and use disorder - a narrative review

The opioid epidemic and limited access to treatment for opioid withdrawal (OW) and opioid use disorder (OUD) has led individuals to seek alternative treatments. This narrative review aims to educate clinicians on the mechanisms of action, toxicity, and applications of psychoactive plant-based substances patients may be using to self-treat OUD and OW. We specifically discuss ayahuasca, ibogaine, and kratom as they have the most evidence for applications in OUD and OW from the last decade (2012-2022). Evidence suggests these substances may have efficacy in treating OW and OUD through several therapeutic mechanisms including their unique pharmacodynamic effects, rituals performed around ingestion, and increased neuroplasticity. The current evidence for their therapeutic application in OUD and OW is primarily based on small observational studies or animal studies. High-quality, longitudinal studies are needed to clarify safety and efficacy of these substances in treatment of OW and OUD.

What We Have Gained from Ibogaine: α3β4 Nicotinic Acetylcholine Receptor Inhibitors as Treatments for Substance Use Disorders

For decades, ibogaine─the main psychoactive alkaloid found in Tabernanthe iboga─has been investigated as a possible treatment for substance use disorders (SUDs) due to its purported ability to interrupt the addictive properties of multiple drugs of abuse. Of the numerous pharmacological actions of ibogaine and its derivatives, the inhibition of α3β4 nicotinic acetylcholine receptors (nAChRs), represents a probable mechanism of action for their apparent anti-addictive activity. In this Perspective, we examine several classes of compounds that have been discovered and developed to target α3β4 nAChRs. Specifically, by focusing on compounds that have proven efficacious in pre-clinical models of drug abuse and have been evaluated clinically, we highlight the promising potential of the α3β4 nAChRs as viable targets to treat a wide array of SUDs. Additionally, we discuss the challenges faced by the existing classes of α3β4 nAChR ligands that must be overcome to develop them into therapeutic treatments.

The Bright Side of Psychedelics: Latest Advances and Challenges in Neuropharmacology

The need to identify effective therapies for the treatment of psychiatric disorders is a particularly important issue in modern societies. In addition, difficulties in finding new drugs have led pharmacologists to review and re-evaluate some past molecules, including psychedelics. For several years there has been growing interest among psychotherapists in psilocybin or lysergic acid diethylamide for the treatment of obsessive-compulsive disorder, of depression, or of post-traumatic stress disorder, although results are not always clear and definitive. In fact, the mechanisms of action of psychedelics are not yet fully understood and some molecular aspects have yet to be well defined. Thus, this review aims to summarize the ethnobotanical uses of the best-known psychedelic plants and the pharmacological mechanisms of the main active ingredients they contain. Furthermore, an up-to-date overview of structural and computational studies performed to evaluate the affinity and binding modes to biologically relevant receptors of ibogaine, mescaline, N,N-dimethyltryptamine, psilocin, and lysergic acid diethylamide is presented. Finally, the most recent clinical studies evaluating the efficacy of psychedelic molecules in some psychiatric disorders are discussed and compared with drugs already used in therapy.

Structure-Activity Relationships of Dopamine Transporter Pharmacological Chaperones

Mutations in the dopamine transporter gene (SLC6A3) have been implicated in many human diseases. Among these is the infantile parkinsonism-dystonia known as Dopamine Transporter Deficiency Syndrome (DTDS). Afflicted individuals have minimal to no functional dopamine transporter protein. This is primarily due to retention of misfolded disease-causing dopamine transporter variants. This results in a variety of severe motor symptoms in patients and the disease ultimately leads to death in adolescence or young adulthood. Though no treatment is currently available, pharmacological chaperones targeting the dopamine transporter have been shown to rescue select DTDS disease-causing variants. Previous work has identified two DAT pharmacological chaperones with moderate potency and efficacy: bupropion and ibogaine. In this study, we carried out structure-activity relationships (SARs) for bupropion and ibogaine with the goal of identifying the chemical features required for pharmacological chaperone activity. Our results show that the isoquinuclidine substituent of ibogaine and its analogs is an important feature for pharmacological chaperone efficacy. For bupropion, the secondary amine group is essential for pharmacological chaperone activity. Lastly, we describe additional ibogaine and bupropion analogs with varying chemical modifications and variable pharmacological chaperone efficacies at the dopamine transporter. Our results contribute to the design and refinement of future dopamine transporter pharmacological chaperones with improved efficacies and potencies.

Safety of ibogaine administration in detoxification of opioid-dependent individuals: a descriptive open-label observational study

BACKGROUND AND AIMS

Ibogaine is an indole alkaloid used in rituals of the African Bwiti tribe. It is also used in non-medical settings to treat addiction. However, ibogaine has been linked to several deaths, mainly due to cardiac events called torsades des pointes preceded by QTc prolongation as well as other safety concerns. This study aimed to evaluate the cardiac, cerebellar and psychomimetic safety of ibogaine in patients with opioid use disorder.

DESIGN

A descriptive open-label observational study.

SETTING

Department of psychiatry in a university medical center, the Netherlands.

PARTICIPANTS

Patients with opioid use disorder (n = 14) on opioid maintenance treatment with a lasting wish for abstinence, who failed to reach abstinence with standard care.

INTERVENTION AND MEASUREMENTS

After conversion to morphine-sulphate, a single dose of ibogaine-HCl 10 mg/kg was administered and patients were monitored at regular intervals for at least 24 hours assessing QTc, blood pressure and heart rate, scale for the assessment and rating of ataxia (SARA) to assess cerebellar side effects and the delirium observation scale (DOS) to assess psychomimetic effects.

FINDINGS

The maximum QTc (Fridericia) prolongation was on average 95ms (range 29-146ms). Fifty percent of subjects reached a QTc of over 500ms during the observation period. In six out 14 subjects prolongation above 450ms lasted beyond 24 hours after ingestion of ibogaine. No torsades des pointes were observed. Severe transient ataxia with inability to walk without support was seen in all patients. Withdrawal and psychomimetic effects were mostly well-tolerated and manageable (11/14 did not return to morphine within 24 hours, DOS scores remained below threshold).

CONCLUSIONS

This open-label observational study found that ibogaine treatment of patients with opioid use disorder can induce a clinically relevant but reversible QTc prolongation, bradycardia, and severe ataxia.

Ibogaine-Mediated ROS/Antioxidant Elevation in Isolated Rat Uterus Is β-Adrenergic Receptors and KATP Channels Mediated

Ibogaine effects are mediated by cellular receptors, ATP depletion followed by ROS production and antioxidant enzyme activity elevation in a dose and time dependent manner. Since the role of K_ATP channels and β-adrenoceptors in ROS cellular circuit was established here we explored their role in ibogaine pro-antioxidant effectiveness. Single dose of ibogaine (10 mg/L i.e., 28.8 μmol/L) was applied to isolated rat uterus (spontaneous and Ca²⁺-stimulated) and contractility and antioxidant enzymes activity were monitored during 4 h. Ibogaine increased amplitude and frequency of spontaneous active uteri immediately after addition that was prevented by propranolol (β₁ and β₂ adrenoceptors selective antagonists) and glibenclamide (K_ATP sensitive channels inhibitor; only frequency) pre-treatment. In Ca²⁺-stimulated uteri, ibogaine decreased both amplitude and frequency after 4 h. Pre-treatment with propranolol abolished ibogaine induced amplitude lowering, while glibenclamide had no effect. In both types of active uterus, ibogaine induced a decrease in SOD1 and an increase in CAT activity after 2 h. In Ca²⁺-stimulated uterus, there was also a decrease of SOD2 activity after 2 h. After 4 h, SOD1 activity returned to the baseline level, but GSH-Px activity increased. Pre-treatment with both propranolol and glibenclamide abolished observed changes of antioxidant enzymes activity suggesting that ibogaine pro-antioxidative effectiveness is β-adrenergic receptors and K_ATP channels mediated.

Ibogaine Blocks Cue- and Drug-Induced Reinstatement of Conditioned Place Preference to Ethanol in Male Mice

Ibogaine is a psychedelic extracted from the plant Tabernanthe iboga Baill. (Apocynaceae), natural from Africa, and has been proposed as a potential treatment for substance use disorders. In animal models, ibogaine reduces ethanol self-administration. However, no study to date has investigated the effects of ibogaine on ethanol-induced conditioned place preference (CPP). The present study aimed to investigate the effects of repeated treatment with ibogaine on the reinstatement of CPP to ethanol in male mice. The rewarding effects of ethanol (1.8 g/kg, i. p.) or ibogaine (10 or 30 mg/kg, p. o.) were investigated using the CPP model. Furthermore, we evaluated the effects of repeated treatment with ibogaine (10 or 30 mg/kg, p. o.) on the reinstatement of ethanol-induced CPP. Reinstatement was evaluated under two conditions: 1) during a priming injection re-exposure test in which animals received a priming injection of ethanol and had free access to the CPP apparatus; 2) during a drug-free test conducted 24 h after a context-paired re-exposure, in which subjects received an injection of ethanol and were confined to the compartment previously conditioned to ethanol. Our results show that ethanol, but not ibogaine, induced CPP in mice. Treatment with ibogaine after conditioning with ethanol blocked the reinstatement of ethanol-induced CPP, both during a drug priming reinstatement test and during a drug-free test conducted after re-exposure to ethanol in the ethanol-paired compartment. Our findings add to the literature suggesting that psychedelics, in particular ibogaine, may have therapeutic properties for the treatment of alcohol use disorder at doses that do not have rewarding effects per se.

Engineering Safer Psychedelics for Treating Addiction

Addiction is best described as a disorder of maladaptive neuroplasticity involving the simultaneous strengthening of reward circuitry that drives compulsive drug seeking and weakening of circuits involved in executive control over harmful behaviors. Psychedelics have shown great promise for treating addiction, with many people attributing their therapeutic effects to insights gained while under the influence of the drug. However, psychedelics are also potent psychoplastogens—molecules capable of rapidly re-wiring the adult brain. The advent of non-hallucinogenic psychoplastogens with anti-addictive properties raises the intriguing possibility that hallucinations might not be necessary for all therapeutic effects of psychedelic-based medicines, so long as the underlying pathological neural circuitry can be remedied. One of these non-hallucinogenic psychoplastogens, tabernanthalog (TBG), appears to have long-lasting therapeutic effects in preclinical models relevant to alcohol and opioid addiction. Here, we discuss the implications of these results for the development of addiction treatments, as well as the next steps for advancing TBG and related non-hallucinogenic psychoplastogens as addiction therapeutics.

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.

Psychedelic Treatment for Trauma-Related Psychological and Cognitive Impairment Among US Special Operations Forces Veterans

BACKGROUND

U.S. Special Operations Forces Veterans are at increased risk for a variety of mental health problems and cognitive impairment associated with military service. Current treatments are lacking in effectiveness and adherence. Therefore, this study examined psychedelic treatment with ibogaine and 5-methoxy-N,N-dimethyltryptamine for trauma-related psychological and cognitive impairment among U.S. Special Operations Forces Veterans.

METHOD

We conducted a survey of Veterans who completed a specific psychedelic clinical program in Mexico between 2017 and 2019. Questions probed retrospective reports of mental health and cognitive functioning during the 30 days before and 30 days after treatment. A total of 65 people completed treatment during this time frame and were eligible for contact. Of these, 51 (78%) completed the survey and were included in data analyses (mean age = 40; male = 96%; married = 55%; Caucasian/White = 92%; Operation Enduring Freedom/Operation Iraqi Freedom Service = 96%).

RESULTS

Results indicated significant and very large reductions in retrospective report of suicidal ideation (p < .001; d = -1.9), cognitive impairment (p < .001; d = -2.8), and symptoms of posttraumatic stress disorder (p < .001; d = -3.6), depression (p < .001; d = -3.7), and anxiety (p < .001; d = -3.1). Results also showed a significant and large increase in retrospective report of psychological flexibility (p < .001; d = 2.9) from before-to-after the psychedelic treatment. Increases in the retrospective report of psychological flexibility were strongly associated with retrospective report of reductions in cognitive impairment, and symptoms of posttraumatic stress disorder, depression, and anxiety (rs range -0.61 to -0.75; p < .001). Additionally, most participants rated the psychedelic experiences as one of the top five personally meaningful (84%), spiritually significant (88%), and psychologically insightful (86%) experiences of their lives.Limitations: Several limitations should be considered including the retrospective, self-report, survey design of the study, and the lack of randomization and blinding, thus making these finding preliminary.

CONCLUSION

U.S. Special Operations Forces Veterans may have unique treatment needs because of the sequela of problems associated with repeated trauma exposure and the nature of the exposure. Psychedelic-assisted therapy with these under-researched psychedelics may hold unique promise for this population. However, controlled studies are needed to determine whether this treatment is efficacious in relieving mental health and cognitive impairment among U.S. Special Operations Forces Veterans.

Extraction and Conversion Studies of the Antiaddictive Alkaloids Coronaridine, Ibogamine, Voacangine, and Ibogaine from Two Mexican Tabernaemontana Species (Apocynaceae)

Several species from the Apocynaceae family, such as Tabernanthe iboga, Voacanga africana, and many Tabernaemontana species, produce ibogan type alkaloids, some of which present antiaddictive properties. In this study, we used gas chromatography/mass spectrometry (GC/MS) to examine the efficiency of methanol, acetone, ethyl acetate, dichloromethane, chloroform, and hydrochloric acid in extracting the antiaddictive compounds coronaridine, ibogamine, voacangine, and ibogaine (altogether the CIVI-complex) from the root barks of Tabernaemontana alba and Tabernaemontana arborea. These Mexican species have recently shown great potential as alternative natural sources of the aforementioned substances. Methanol proved to be the most suitable solvent. Furthermore, the crude methanolic extracts could be engaged in a one-step demethoxycarbonylation process that converted coronaridine and voacangine directly into its non-carboxylic counterparts ibogamine and ibogaine, respectively, without the intermediacy of their carboxylic acids. The established protocol straightforwardly simplifies the alkaloid mixture from four to two majority compounds. In summary, our findings facilitate and improve both the qualitative and quantitative analysis of CIVI-complex-containing plant material, as well as outlining a viable method for the bulk production of these scientifically and pharmaceutically important substances from Mexican Tabernaemontana species.

Metabolite Profiling of Anti-Addictive Alkaloids from Four Mexican Tabernaemontana Species and the Entheogenic African Shrub Tabernanthe iboga (Apocynaceae)

Ibogaine and other ibogan type alkaloids present anti-addictive effects against several drugs of abuse and occur in different species of the Apocynaceae family. In this work, we used gas chromatography-mass spectrometry (GC/MS) and principal component analysis (PCA) in order to compare the alkaloid profiles of the root and stem barks of four Mexican Tabernaemontana species with the root bark of the entheogenic African shrub Tabernanthe iboga. PCA demonstrated that separation between species could be attributed to quantitative differences of the major alkaloids, coronaridine, ibogamine, voacangine, and ibogaine. While T. iboga mainly presented high concentrations of ibogaine, Tabernaemontana samples either showed a predominance of voacangine and ibogaine, or coronaridine and ibogamine, respectively. The results illustrate the phytochemical proximity between both genera and confirm previous suggestions that Mexican Tabernaemontana species are viable sources of anti-addictive compounds.

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.

Cardiac arrest after ibogaine intoxication

Ibogaine is a psychoactive herbal medication with alleged antiaddiction properties. We report a case of ibogaine intoxication mimicking Long-QT syndrome resulting in ventricular flutter and nearby cardiac arrest. A 61-year-old man experienced massive QT prolongation and ventricular flutter at a rate of 270 beats per minute requiring defibrillation after ingestion of a large dose of Ibogaine. The ingested dose of 65-70 mg/kg represents the highest survived ibogaine dose reported to date. As a result of the long plasma half-life of ibogaine, it took 7 days for the patient's QT interval to normalize.

Cytochrome P450 and O-methyltransferase catalyze the final steps in the biosynthesis of the anti-addictive alkaloid ibogaine from Tabernanthe iboga

Monoterpenoid indole alkaloids are a large (∼3000 members) and structurally diverse class of metabolites restricted to a limited number of plant families in the order Gentianales. Tabernanthe iboga or iboga (Apocynaceae) is native to western equatorial Africa and has been used in traditional medicine for centuries. Howard Lotsof is credited with bringing iboga to the attention of Western medicine through his accidental discovery that iboga can alleviate opioid withdrawal symptoms. Since this observation, iboga has been investigated for its use in the general management of addiction. We were interested in elucidating ibogaine biosynthesis to understand the unique reaction steps en route to ibogaine. Furthermore, because ibogaine is currently sourced from plant material, these studies may help improve the ibogaine supply chain through synthetic biology approaches. Here, we used next-generation sequencing to generate the first iboga transcriptome and leveraged homology-guided gene discovery to identify the penultimate hydroxylase and final O-methyltransferase steps in ibogaine biosynthesis, herein named ibogamine 10-hydroxylase (I10H) and noribogaine-10-O-methyltransferase (N10OMT). Heterologous expression in Saccharomyces cerevisiae (I10H) or Escherichia coli (N10OMT) and incubation with putative precursors, along with HPLC-MS analysis, confirmed the predicted activities of both enzymes. Moreover, high expression levels of their transcripts were detected in ibogaine-accumulating plant tissues. These discoveries coupled with our publicly available iboga transcriptome will contribute to additional gene discovery efforts and could lead to the stabilization of the global ibogaine supply chain and to the development of ibogaine as a treatment for addiction.

Psychedelic-Assisted Psychotherapy: A Paradigm Shift in Psychiatric Research and Development

Mental disorders are rising while development of novel psychiatric medications is declining. This stall in innovation has also been linked with intense debates on the current diagnostics and explanations for mental disorders, together constituting a paradigmatic crisis. A radical innovation is psychedelic-assisted psychotherapy (PAP): professionally supervised use of ketamine, MDMA, psilocybin, LSD and ibogaine as part of elaborated psychotherapy programs. Clinical results so far have shown safety and efficacy, even for “treatment resistant” conditions, and thus deserve increasing attention from medical, psychological and psychiatric professionals. But more than novel treatments, the PAP model also has important consequences for the diagnostics and explanation axis of the psychiatric crisis, challenging the discrete nosological entities and advancing novel explanations for mental disorders and their treatment, in a model considerate of social and cultural factors, including adversities, trauma, and the therapeutic potential of some non-ordinary states of consciousness.

Ibogaine Detoxification Transitions Opioid and Cocaine Abusers Between Dependence and Abstinence: Clinical Observations and Treatment Outcomes

Ibogaine may be effective for transitioning opioid and cocaine dependent individuals to sobriety. American and European self-help groups provided public testimonials that ibogaine alleviated drug craving and opioid withdrawal symptoms after only a single dose administration. Preclinical studies in animal models of addiction have provided proof-of-concept evidence in support of these claims. However, the purported therapeutic benefits of ibogaine are based on anecdotal reports from a small series of case reports that used retrospective recruitment procedures. We reviewed clinical results from an open label case series (N = 191) of human volunteers seeking to detoxify from opioids or cocaine with medical monitoring during inpatient treatment. Whole blood was assayed to obtain pharmacokinetic measures to determine the metabolism and clearance of ibogaine. Clinical safety data and adverse events (AEs) were studied in male and female subjects. There were no significant adverse events following administration of ibogaine in a dose range that was shown to be effective for blocking opioid withdrawal symptoms in this study. We used multi-dimensional craving questionnaires during inpatient detoxification to test if ibogaine was effective in diminishing heroin and cocaine cravings. Participants also completed standardized questionnaires about their health and mood before and after ibogaine treatment, and at program discharge. One-month follow-up data were reviewed where available to determine if ibogaine's effects on drug craving would persist outside of an inpatient setting. We report here that ibogaine therapy administered in a safe dose range diminishes opioid withdrawal symptoms and reduces drug cravings. Pharmacological treatments for opioid dependence include detoxification, narcotic antagonists and long-term opioid maintenance therapy. Our results support product development of single oral dose administration of ibogaine for the treatment of opioid withdrawal during medically supervised detoxification to transition drug dependent individuals to abstinence.

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

Ibogaine is a potent psychedelic alkaloid that has been the focus of intense research because of its intriguing anti-addictive properties. According to anecdotic reports, ibogaine has been originally classified as an oneirogenic psychedelic; i.e., induces a dream-like cognitive activity while awake. However, the effects of ibogaine administration on wakefulness (W) and sleep have not been thoroughly assessed. The main aim of our study was to characterize the acute effects of ibogaine administration on W and sleep. For this purpose, polysomnographic recordings on chronically prepared rats were performed in the light phase during 6 h. Animals were treated with ibogaine (20 and 40 mg/kg) or vehicle, immediately before the beginning of the recordings. Furthermore, in order to evaluate associated motor behaviors during the W period, a different group of animals was tested for 2 h after ibogaine treatment on an open field with video-tracking software. Compared to control, animals treated with ibogaine showed an increase in time spent in W. This effect was accompanied by a decrease in slow wave sleep (SWS) and rapid-eye movements (REM) sleep time. REM sleep latency was significantly increased in animals treated with the higher ibogaine dose. While the effects on W and SWS were observed during the first 2 h of recordings, the decrement in REM sleep time was observed throughout the recording time. Accordingly, ibogaine treatment with the lower dose promoted an increase on locomotion, while tremor and flat body posture were observed only with the higher dose in a time-dependent manner. In contrast, head shake response, a behavior which has been associated in rats with the 5HT_2A receptor activation by hallucinogens, was not modified. We conclude that ibogaine promotes a waking state that is accompanied by a robust and long-lasting REM sleep suppression. In addition, it produces a dose-dependent unusual motor profile along with other serotonin-related behaviors. Since ibogaine is metabolized to produce noribogaine, further experiments are needed to elucidate if the metabolite and/or the parent drug produced these effects.

Changes in Withdrawal and Craving Scores in Participants Undergoing Opioid Detoxification Utilizing Ibogaine

Opioid use disorder (OUD) is currently an epidemic in the United States (US) and ibogaine is reported to have the ability to interrupt opioid addiction by simultaneously mitigating withdrawal and craving symptoms. This study examined opioid withdrawal and drug craving scores in 50 participants with OUD undergoing a week-long detoxification treatment protocol with ibogaine. The Addiction Severity Index (ASI) was used for baseline characterization of participants' OUD. Clinical Opioid Withdrawal Scale (COWS), Subjective Opioid Withdrawal Scale (SOWS), and Brief Substance Craving Scale (BSCS) scores were collected at 48 and 24 hours prior to ibogaine administration, as well as 24 and 48 hours after ibogaine administration. At 48 hours following ibogaine administration, withdrawal and craving scores were significantly lowered in comparison to baseline: 78% of patients did not exhibit objective clinical signs of opioid withdrawal, 79% reported minimal cravings for opioids, and 68% reported subjective withdrawal symptoms in the mild range. Ibogaine appears to facilitate opioid detoxification by reducing opioid withdrawal and craving in participants with OUD. These results warrant further research using rigorous controlled trials.

Subjective effectiveness of ibogaine treatment for problematic opioid consumption: Short- and long-term outcomes and current psychological functioning

Background and aims

Very few studies have reported the effectiveness of ibogaine as a treatment for chronic opioid use. Therefore, this study evaluated the acute subjective effects of ibogaine, outcomes on problematic opioid consumption, and the long-term associations with psychological functioning.

Methods

Using online data collection, 88 patients who received ibogaine treatment in Mexico between 2012 and 2015 completed our survey.

Results

Most participants (72%) had used opioids for at least 4 years and 69% reported daily use. Most (80%) indicated that ibogaine eliminated or drastically reduced withdrawal symptoms. Fifty percent reported that ibogaine reduced opioid craving, some (25%) reporting a reduction in craving lasting at least 3 months. Thirty percent of participants reported never using opioids again following ibogaine treatment. And over one half (54%) of these abstainers had been abstinent for at least 1 year, with 31% abstinent for at least 2 years. At the time of survey, 41% of all participants reported sustained abstinence (>6 months). Although 70% of the total sample reported a relapse following treatment, 48% reported decreased use from pretreatment levels and an additional 11% eventually achieved abstinence. Treatment responders had the lowest rates of depressive and anxious symptoms, the highest levels of subjective well-being and rated their ibogaine treatment as more spiritually meaningful compared with treatment non-responders.

Conclusion

The results suggest that ibogaine is associated with reductions in opioid use, including complete abstinence, and has long-term positive psychological outcomes. Future research should investigate the efficacy of ibogaine treatment using rigorous longitudinal and controlled designs.

Pharmacological Chaperones of the Dopamine Transporter Rescue Dopamine Transporter Deficiency Syndrome Mutations in Heterologous Cells

A number of pathological conditions have been linked to mutations in the dopamine transporter gene, including hereditary dopamine transporter deficiency syndrome (DTDS). DTDS is a rare condition that is caused by autosomal recessive loss-of-function mutations in the dopamine transporter (DAT), which often affects transporter trafficking and folding. We examined the possibility of using pharmacological chaperones of DAT to rescue DTDS mutations. After screening a set of known DAT ligands for their ability to increase DAT surface expression, we found that bupropion and ibogaine increased DAT surface expression, whereas others, including cocaine and methylphenidate, had no effect. Bupropion and ibogaine increased wild type DAT protein levels and also promoted maturation of the endoplasmic reticulum (ER)-retained DAT mutant K590A. Rescue of K590A could be blocked by inhibiting ER to Golgi transport using brefeldin A. Furthermore, knockdown of coat protein complex II (COPII) component SEC24D, which is important in the ER export of wild type DAT, also blocked the rescue effects of bupropion and ibogaine. These data suggest that bupropion and ibogaine promote maturation of DAT by acting as pharmacological chaperones in the ER. Importantly, both drugs rescue DAT maturation and functional activity of the DTDS-associated mutations A314V and R445C. Together, these results are the first demonstration of pharmacological chaperoning of DAT and suggest this may be a viable approach to increase DAT levels in DTDS and other conditions associated with reduced DAT function.

[Ibogaine - structure, influence on human body, clinical relevance]

Ibogaine is a natural chemical compound, which belongs to the indole alkaloid family. It can be naturally found within the root bark of african plant Tabernanthe iboga. Ibogaine plays a significant role among tribal cultures. Ibogaine, in small amount, causes reduction of hunger, thirst and exhaustion. In bigger amount, however, it can cause intensive visions. Other effects include reduction or complete disappearance of absitnence symptoms visible in people addicted to the nicotine, alcohol, methamphetamine, cocaine or opioids, what has been scientifically proven after the tests on animals and small groups of people. After oral application, 80% of ibogaine is subjected to the Odemethylation into noribogaine; main catalyzing enzyme is cytochrome CYP2D6. Research suggests, that ibogaine acts in many places within central nervous system. NMDA receptors seem to play main role in its anti-addiction properties. It is important to mention the side effects of the compound, which are cardiotoxicity and neurotoxicity, what makes it harder to use its beneficial properties. Because of this, Ibogaine is included among the dangerous substance. However, there are a few clinics in the world which specializes in the use of the compound in order to interrupt the sypmtoms acute opioid withdrawal syndrome as well as a substance benficial in curing other addictions. There is more hope with synthetic derivatives of ibogaine, which although are less toxic still keep their anti-addiction properties. The aim is to collect the available knowledge related to the structure and effects on human body of alkaloid Tabernanthe iboga and consider the possibility of commercial medical use.

Oral noribogaine shows high brain uptake and anti-withdrawal effects not associated with place preference in rodents

This study investigated the effects of noribogaine, the principal metabolite of the drug ibogaine, on substance-related disorders. In the first experiment, mice chronically treated with morphine were subjected to naloxone-precipitated withdrawal two hours after oral administration of noribogaine. Oral noribogaine dose dependently decreased the global opiate withdrawal score by up to 88% of vehicle control with an ED50 of 13 mg/kg. In the second experiment, blood and brain levels of noribogaine showed a high brain penetration and a brain/blood ratio of 7±1 across all doses tested. In a third experiment, rats given oral noribogaine up to 100 mg/kg were tested for abuse liability using a standard biased conditioned place paradigm. Noribogaine-treated rats did not display place preference, suggesting that noribogaine is not perceived as a hedonic stimulus in rodents. Retrospective review of published studies assessing the efficacy of ibogaine on morphine withdrawal shows that the most likely cause of the discrepancies in the literature is the different routes of administration and time of testing following ibogaine administration. These results suggest that the metabolite noribogaine rather than the parent compound mediates the effects of ibogaine on blocking naloxone-precipitated withdrawal. Noribogaine may hold promise as a non-addicting alternative to standard opiate replacement therapies to transition patients to opiate abstinence.

Control of serotonin transporter phosphorylation by conformational state

Serotonin transporter (SERT) is responsible for reuptake and recycling of 5-hydroxytryptamine (5-HT; serotonin) after its exocytotic release during neurotransmission. Mutations in human SERT are associated with psychiatric disorders and autism. Some of these mutations affect the regulation of SERT activity by cGMP-dependent phosphorylation. Here we provide direct evidence that this phosphorylation occurs at Thr276, predicted to lie near the cytoplasmic end of transmembrane helix 5 (TM5). Using membranes from HeLa cells expressing SERT and intact rat basophilic leukemia cells, we show that agents such as Na(+) and cocaine that stabilize outward-open conformations of SERT decreased phosphorylation and agents that stabilize inward-open conformations (e.g., 5-HT, ibogaine) increased phosphorylation. The opposing effects of the inhibitors cocaine and ibogaine were each reversed by an excess of the other inhibitor. Inhibition of phosphorylation by Na(+) and stimulation by ibogaine occurred at concentrations that induced outward opening and inward opening, respectively, as measured by the accessibility of cysteine residues in the extracellular and cytoplasmic permeation pathways, respectively. The results are consistent with a mechanism of SERT regulation that is activated by the transport of 5-HT, which increases the level of inward-open SERT and may lead to unwinding of the TM5 helix to allow phosphorylation.

Ibogaine-associated cardiac arrest and death: case report and review of the literature

A naturally occurring hallucinogenic plant alkaloid, ibogaine has been used as an adjuvant for opiate withdrawal for the past 50 years. In the setting of an escalating nationwide opiate epidemic, use of substances such as ibogaine may also increase. Therefore, familiarity with the mechanisms and potential adverse effects of ibogaine is important for clinicians. We present the case report of a man whose use of ibogaine resulted in cardiac arrest and death, complemented by a review of the literature regarding ibogaine's clinical effects. A 40-year-old man who used ibogaine for symptoms of heroin withdrawal suffered acute cardiac arrest leading to cerebral edema and brain death. His presentation was consistent with ibogaine-induced cardiotoxicity and ibogaine-induced cardiac arrest, and a review of the literature regarding the history, mechanisms, risks and clinical outcomes associated with ibogaine is presented. The case presented underscores the significant potential clinical risks of ibogaine. It is important the healthcare community be aware of the possible effects of ibogaine such that clinicians can provide informed counseling to their patients regarding the risks of attempting detoxification with ibogaine.

Anti-addiction drug ibogaine inhibits hERG channels: a cardiac arrhythmia risk

Ibogaine, an alkaloid derived from the African shrub Tabernanthe iboga, has shown promising anti-addictive properties in animals. Anecdotal evidence suggests that ibogaine is also anti-addictive in humans. Thus, it alleviates drug craving and impedes relapse of drug use. Although not licensed as therapeutic drug, and despite evidence that ibogaine may disturb the rhythm of the heart, this alkaloid is currently used as an anti-addiction drug in alternative medicine. Here, we report that therapeutic concentrations of ibogaine reduce currents through human ether-a-go-go-related gene potassium channels. Thereby, we provide a mechanism by which ibogaine may generate life-threatening cardiac arrhythmias.

Fatal case of a 27-year-old male after taking iboga in withdrawal treatment: GC-MS/MS determination of ibogaine and ibogamine in iboga roots and postmortem biological material

We report the case of a man who died twelve hours after ingesting powdered iboga root, commonly taken for its stimulant and hallucinogenic properties. Ibogaine and ibogamine were quantified in the powder ingested and the victim's body fluids by GC-MS/MS after liquid-liquid extraction (Toxi-tubes A(®)). The concentrations of ibogaine measured in the blood samples taken at the scene and in the peripheral blood, urine, and gastric fluid samples taken during the autopsy were 0.65, 1.27, 1.7, and 53.5 μg/mL, while the iboga content in the powder was 7.2%. Moreover, systematic toxicological analyses of biological samples showed the presence of diazepam and methadone in therapeutic concentrations. Death was attributed to the ingestion of a substantial quantity of iboga in the context of simultaneous methadone and diazepam consumption.

Analysis of electrical brain waves in neurotoxicology: γ-hydroxybutyrate

Advances in computer technology have allowed quantification of the electroencephalogram (EEG) and expansion of quantitative EEG (qEEG) analysis in neurophysiology, as well as clinical neurology, with great success. Among the variety of techniques in this field, frequency (spectral) analysis using Fast Fourier Transforms (FFT) provides a sensitive tool for time-course studies of different compounds acting on particular neurotransmitter systems. Studies presented here include Electrocorticogram (ECoG) analysis following exposure to a glutamic acid analogue - domoic acid (DOM), psychoactive indole alkaloid - ibogaine, as well as cocaine and gamma-hydroxybutyrate (GHB). The ECoG was recorded in conscious rats via a tether and swivel system. The EEG signal frequency analysis revealed an association between slow-wave EEG activity delta and theta and the type of behavioral seizures following DOM administration. Analyses of power spectra obtained in rats exposed to cocaine alone or after pretreatment with ibogaine indicated the contribution of the serotonergic system in ibogaine mediated response to cocaine (increased power in alpha(1) band). Ibogaine also lowered the threshold for cocaine-induced electrographic seizures (increased power in the low-frequency bands, delta and theta). Daily intraperitoneal administration of cocaine for two weeks was associated with a reduction in slow-wave ECoG activity 24 hrs following the last injection when compared with controls. Similar decreased cortical activity in low-frequency bands observed in chronic cocaine users has been associated with reduced metabolic activity in the frontal cortex. The FFT analyses of power spectra relative to baseline indicated a significant energy increase over all except beta(2) frequency bands following exposure to 400 and 800 mg/kg GHB. The EEG alterations detected in rats following exposure to GHB resemble absence seizures observed in human petit mal epilepsy. Spectral analysis of the EEG signals combined with behavioral observations may prove to be a useful approach in studying chronic exposure to drugs of abuse and treatment of drug dependence.

Characterization of the discriminable stimulus produced by 2-BFI: effects of imidazoline I(2)-site ligands, MAOIs, beta-carbolines, agmatine and ibogaine

1. The molecular nature and functions of the I(2) subtype of imidazoline binding sites are unknown but evidence suggests an association with monoamine oxidase (MAO). Rats can distinguish the selective imidazoline I(2)-site ligand 2-BFI from vehicle in drug discrimination, indicating functional consequences of occupation of these sites. We have used drug discrimination to investigate the nature of the discriminable stimulus, especially in relation to MAO inhibition. 2. Following training to distinguish 2-BFI 7 mg kg(-1) i.p. from saline vehicle in two-lever operant-chambers, male Hooded Lister rats underwent sessions where test substances were given instead and the proportion of lever presses on the 2-BFI-associated lever (substitution) recorded. 3. 2-BFI; its cogeners BU216, BU224, BU226 and LSL60101; the reversible MAO-A inhibitors moclobemide and RO41-1049; the beta-carbolines harmane, norharmane and harmaline which also reversibly inhibit MAO-A, and the anti-addictive substance ibogaine exhibited potent, dose-dependent substitution for 2-BFI. 4. Agmatine, and LSL60125 substituted at one dose only. The reversible MAO-B inhibitors lazabemide and RO16-1649; the sigma(2)-site ligand SKF10,047 and the I(2A)-site ligand, amiloride, failed to substitute. The irreversible inhibitor of MAO, deprenyl, substituted for 2-BFI while clorgyline did not. 5. These results suggest imidazoline I(2) site ligands produce a common discriminable stimulus that appears associated with reversible inhibition of MAO-A rather than MAO-B, possibly through increases in extracellular concentration of one or more monoamines. Ibogaine exhibits a commonality in its subjective effects with those of I(2)-site ligands.

Pharmacological comparison of the effect of ibogaine and 18-methoxycoronaridine on isolated smooth muscle from the rat and guinea-pig

Ibogaine and 18-methoxycoronaridine are naturally occurring alkaloids reported to possess antiaddictive properties in several models of drug dependence. We have examined their effect at mu-opioid receptors regulating neurogenic contractions of several smooth muscle preparations and also against spontaneous contractions of the rat isolated portal vein. Ibogaine (pIC(50) 5.28) and 18-methoxycoronaridine (pIC(50) 5.05) caused a concentration-dependent inhibition of cholinergic contractions of the guinea-pig ileum which was not affected by the opioid receptor antagonist naloxone (1 microM). In the rat isolated vas deferens ibogaine and 18-methoxycoronaridine caused a concentration-dependent enhancement of purinergic contractions. Both agents (30 microM) caused a 3 - 5 fold rightward displacement of DAMGO-induced inhibition of purinergic contractions, but similar effects were observed for ibogaine against alpha(2)-adrenoceptor-mediated inhibition of neurogenic responses. In the guinea-pig isolated bladder both ibogaine (10 microM) and 18-methoxycoronaridine (10 microM) caused a 2 fold increase in the purinergic component of neurogenic contractions without significantly altering cholinergic contractions or responses to exogenous ATP. In contrast, ibogaine (1 - 30 microM), but not 18-methoxycoronaridine, caused a concentration-dependent enhancement of spontaneous contractions of the rat isolated portal vein. In summary, while ibogaine and 18-methoxycoronaridine modulated electrically-evoked contractions in the three preparations examined, we have no evidence for a selective interaction with pre-junctional mu-opioid receptors. The pronounced enhancement of purinergic contractions produced by both agents is a novel finding and worthy of further investigation.

The olivocerebellar projection mediates ibogaine-induced degeneration of Purkinje cells: a model of indirect, trans-synaptic excitotoxicity

Ibogaine, an indole alkaloid that causes hallucinations, tremor, and ataxia, produces cerebellar neurotoxicity in rats, manifested by degeneration of Purkinje cells aligned in narrow parasagittal bands that are coextensive with activated glial cells. Harmaline, a closely related alkaloid that excites inferior olivary neurons, causes the same pattern of Purkinje cell degeneration, providing a clue to the mechanism of toxicity. We have proposed that ibogaine, like harmaline, excites neurons in the inferior olive, leading to sustained release of glutamate at climbing fiber synapses on Purkinje cells. The objective of this study was to test the hypothesis that increased climbing fiber activity induced by ibogaine mediates excitotoxic Purkinje cell degeneration. The inferior olive was pharmacologically ablated in rats by a neurotoxic drug regimen using 3-acetylpyridine, and cerebellar damage attributed to subsequent administration of ibogaine was analyzed using immunocytochemical markers for neurons and glial cells. The results show that ibogaine administered after inferior olive ablation produced little or no Purkinje cell degeneration or glial activation. That a lesion of the inferior olive almost completely prevents the neurotoxicity demonstrates that ibogaine is not directly toxic to Purkinje cells, but that the toxicity is indirect and dependent on integrity of the olivocerebellar projection. We postulate that ibogaine-induced activation of inferior olivary neurons leads to release of glutamate simultaneously at hundreds of climbing fiber terminals distributed widely over the surface of each Purkinje cell. The unique circuitry of the olivocerebellar projection provides this system with maximum synaptic security, a feature that confers on Purkinje cells a high degree of vulnerability to excitotoxic injury.

Ibogaine modulates cocaine responses which are altered due to environmental habituation: in vivo microvoltammetric and behavioral studies

Ibogaine, a serotonergic (5-HTergic) indole alkaloid, was studied for cocaine modulatory effects on four parameters of behavior by computerized infrared photocell beam detection. The behavioral parameters were: a) locomotor activity (ambulations), b) rearing, c) stereotypy (fine movements, primarily grooming), and d) agoraphobia [(thigmotaxis) a natural tendency to avoid the center of the behavioral chamber]. With each behavioral data point, dopamine (DA) release, and serotonin (5-HT) release were detected within seconds in nucleus accumbens (NAcc) of the same behaving male Sprague-Dawley rats, using in vivo electrochemistry (voltammetry). Ibogaine was administered (40 mg/kg IP) for 4 consecutive days. Importantly, the DAergic and the 5-HTergic responses to (SC) cocaine and two behavioral responses, ambulations and central ambulations, were reduced in intensity due to extended time spent in the novel behavioral chamber (habituated). Rearing and fine movement patterns were not habituated. The results show that ibogaine downmodulated the (SC) cocaine-induced increase in NAcc DA release (p < 0.0001) and potentiated the (SC) cocaine-induced decrease in NAcc 5-HT release (p < 0.0001). Concurrently, ibogaine downmodulated cocaine-induced ambulation (p < 0.0001) and central ambulation behavior (p < 0.0001). On the other hand, the behavioral parameters that did not exhibit habituation, i.e., rearing behavior and fine movement behavior, were not downmodulated by ibogaine (p < 0.1558) (p < 0.3763), respectively. Furthermore, ibogaine itself did not significantly alter NAcc DA release over the 2-h period studied (p < 0.9113) although individual time points were significantly affected bidirectionally. Concurrently ibogaine significantly increased 5-HT release (p < 0.0155). Behaviorally, ibogaine appears to be a weak psychostimulant. The data show a critical modulatory role for 5-HT in ibogaine-cocaine interactions. Also elucidated as critical is the efficacy of ibogaine when the response to (SC) cocaine is decreased due to the habituation of the animals to their environment.