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Ibogaine as a treatment for substance misuse: Potential benefits and practical dangers.

Abstract

Ibogaine is an indole alkaloid found in the root bark of the Iboga shrub native to west Africa possessing hallucinogenic properties. For centuries it has been used in religious ceremonies and to gain spiritual enlightenment. However, since the early 1960s, its apparent ability to reduce craving for psychoactive substances including alcohol, cocaine, methamphetamine, opiates, and nicotine has led to its use in detoxification treatments. In many instances, clients receive treatment in non-medical settings, with little by way of robust scientific clinical trials. This chapter provides an overview of the potential benefits that could arise from such research. This is balanced against the serious adverse effects that can occur due to undiagnosed health conditions and/or concomitant use of other drugs. A detailed update is provided of the 33 deaths known to have occurred, including 5 in the UK. Looking forward, there is a need to develop better opiate detoxification treatment against a background of increasing opioid-related fatalities. A congener of ibogaine, 18-MC, appears to be safer and is to undergo clinical trials. In the meantime, would-be consumers and treatment providers must make more careful, detailed risk-assessments before using ibogaine. Treatment outcomes, including deaths, need to be accurately recorded and published.
Corkery, J. M. (2018). Ibogaine as a treatment for substance misuse: Potential benefits and practical dangers. Progress in brain research242, 217-257., 10.1016/bs.pbr.2018.08.005
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Kappa Opioid Receptor Agonist Mesyl Sal B Attenuates Behavioral Sensitization to Cocaine with Fewer Aversive Side-Effects than Salvinorin A in Rodents.

Abstract

The acute activation of kappa opioid receptors (KOPr) produces antinociceptive and anti-cocaine effects, however, their side-effects have limited further clinical development. Mesyl Sal B is a potent and selective KOPr analogue of Salvinorin A (Sal A), a psychoactive natural product isolated from the plant Salvia divinorum. We assessed the antinociceptive, anti-cocaine, and side-effects of Mesyl Sal B. The anti-cocaine effects are evaluated in cocaine-induced hyperactivity and behavioral sensitization to cocaine in male Sprague Dawley rats. Mesyl Sal B was assessed for anhedonia (conditioned taste aversion), aversion (conditioned place aversion), pro-depressive effects (forced swim test), anxiety (elevated plus maze) and learning and memory deficits (novel object recognition). In male B6.SJL mice, the antinociceptive effects were evaluated in warm-water (50 °C) tail withdrawal and intraplantar formaldehyde (2%) assays and the sedative effects measured with the rotarod performance task. Mesyl Sal B (0.3 mg/kg) attenuated cocaine-induced hyperactivity and behavioral sensitization to cocaine without modulating sucrose self-administration and without producing aversion, sedation, anxiety, or learning and memory impairment in rats. However, increased immobility was observed in the forced swim test indicating pro-depressive effects. Mesyl Sal B was not as potent as Sal A at reducing pain in the antinociceptive assays. In conclusion, Mesyl Sal B possesses anti-cocaine effects, is longer acting in vivo and has fewer side-effects when compared to Sal A, however, the antinociceptive effects are limited.
Kivell, B., Paton, K., Kumar, N., Morani, A., Culverhouse, A., Shepherd, A., … & Prisinzano, T. (2018). Kappa Opioid Receptor Agonist Mesyl Sal B Attenuates Behavioral Sensitization to Cocaine with Fewer Aversive Side-Effects than Salvinorin A in Rodents. Molecules23(10), 2602., 10.3390/molecules23102602
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Pharmacokinetic And Pharmacodynamic Aspects Of Peyote And Mescaline: Clinical And Forensic Repercussions

Abstract

BACKGROUND:

Mescaline (3,4,5-trimethoxyphenethylamine), mainly found in the Peyote cactus (Lophophora williamsii), is one of the oldest known hallucinogenic agents that influence human and animal behavior, but its psychoactive mechanisms remain poorly understood.

OBJECTIVES:

This article aims to fully review pharmacokinetics and pharmacodynamics of mescaline, focusing on the in vivo and in vitro metabolic profile of the drug and its implications for the variability of response.

METHODS:

Mescaline pharmacokinetic and pharmacodynamic aspects were searched in books and in PubMed (U.S. National Library of Medicine) without a limiting period. Biological effects of other compounds found in peyote were also reviewed.

RESULTS:

Although its illicit administration is less common, in comparison with cocaine and Cannabis, it has been extensively described in adolescents and young adults, and licit consumption often occurs in religious and therapeutic rituals practiced by the Native American Church. Its pharmacodynamic mechanisms of action are primarily attributed to the interaction with the serotonergic 5-HT2A-C receptors, and therefore clinical effects are similar to those elicited by other psychoactive substances, such as lysergic acid diethylamide (LSD) and psilocybin, which include euphoria, hallucinations, depersonalization and psychoses. Moreover, as a phenethylamine derivative, signs and symptoms are consistent with a sympathomimetic effect. Mescaline is mainly metabolized into trimethoxyphenylacetic acid by oxidative deamination but several minor metabolites with possible clinical and forensic repercussions have also been reported.

CONCLUSION:

Most reports concerning mescaline were described in a complete absence of exposure confirmation, since toxicological analysis is not widely available. Addiction and dependence are practically absent and it is clear that most intoxications appear to be mild and are unlikely to produce life-threatening symptoms, which favors the contemporary interest in the therapeutic potential of the drugs of the class.

Dinis-Oliveira, R. J., Pereira, C. L., & Da Silva, D. D., (2018). Pharmacokinetic And Pharmacodynamic Aspects Of Peyote And Mescaline: Clinical And Forensic Repercussions. Current molecular pharmacology., 10.2174/1874467211666181010154139
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DARK Classics in Chemical Neuroscience: Ibogaine.

Abstract

The West African iboga plant has been used for centuries by the Bwiti and Mbiri tribes to induce hallucinations during religious ceremonies. Ibogaine, the principal alkaloid responsible for iboga’s psychedelic properties, was isolated and sold as an antidepressant in France for decades before its adverse effects precipitated its removal from the market. An ibogaine resurgence in the 1960s was driven by U.S. heroin addicts who claimed that ibogaine cured their opiate addictions. Behavioral pharmacologic studies in animal models provided evidence that ibogaine could blunt self-administration of not only opiates but cocaine, amphetamines, and nicotine. Ibogaine displays moderate-to-weak affinities for a wide spectrum of receptor and transporter proteins; recent work suggests that its actions at nicotinic acetylcholine receptor subtypes may underlie its reputed antiopiate effects. At micromolar levels, ibogaine is neurotoxic and cardiotoxic and has been linked to several deaths by cardiac arrest. Structure-activity studies led to the isolation of the ibogaine analog 18-methoxycoronaridine (18-MC), an α3β4 nicotinic receptor modulator that retains ibogaine’s anticraving properties with few or no adverse effects. Clinical trials of 18-MC treatment of nicotine addiction are pending. Ibogaine analogs may also hold promise for treating anxiety and depression via the “psychedelic-assisted therapy” approach that employs hallucinogens including psilocybin and methylenedioxymethamphetamine (“ecstasy”).
Wasko, M. J., Witt-Enderby, P. A., & Surratt, C. K. (2018). DARK Classics in Chemical Neuroscience: Ibogaine. ACS chemical neuroscience9(10), 2475-2483., 10.1021/acschemneuro.8b00294
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Neuroscience: Modeling the Brain on Acid.

Abstract

A receptor map of serotonin distribution is integrated into a model of the dynamic activity of the brain under the effects of LSD. The approach opens new avenues to understand experimental manipulations of healthy brain activity and offers a novel drug-discovery platform.
van der Meer, J., & Breakspear, M. (2018). Neuroscience: Modeling the Brain on Acid. Current Biology28(19), R1157-R1160. doi: 10.1016/j.cub.2018.08.008, https://doi.org/10.1016/j.cub.2018.08.008
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Increased use of illicit drugs in a Dutch cluster headache population

Abstract

Introduction

Many patients with cluster headache report use of illicit drugs. We systematically assessed the use of illicit drugs and their effects in a well-defined Dutch cluster headache population.

Methods

In this cross-sectional explorative study, 756 people with cluster headache received a questionnaire on lifetime use and perceived effects of illicit drugs. Results were compared with age and sex-matched official data from the Dutch general population.

Results

Compared to the data from the general population, there were more illicit drug users in the cluster headache group (31.7% vs. 23.8%; p < 0.01). Reduction in attack frequency was reported by 56% (n = 22) of psilocybin mushroom, 60% (n = 3) of lysergic acid diethylamide and 50% (n = 2) of heroin users, and a decreased attack duration was reported by 46% (n = 18) of PSI, 50% (n = 2) of heroin and 36% (n = 8) of amphetamine users.

Conclusion

In the Netherlands, people with cluster headache use illicit drugs more often than the general population. The question remains whether this is due to an actual alleviatory effect, placebo response, conviction, or common pathophysiological background between cluster headache and addictive behaviours such as drug use.

de Coo, I. F., Naber, W. C., Wilbrink, L. A., Haan, J., Ferrari, M. D., & Fronczek, R. (2018). Increased use of illicit drugs in a Dutch cluster headache population. Cephalalgia., 10.1177/0333102418804160
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The neuropharmacology of sleep paralysis hallucinations: serotonin 2A activation and a novel therapeutic drug

Abstract

Sleep paralysis is a state of involuntary immobility occurring at sleep onset or offset, often accompanied by uncanny “ghost-like” hallucinations and extreme fear reactions. I provide here a neuropharmacological account for these hallucinatory experiences by evoking the role of the serotonin 2A receptor (5-HT2AR). Research has shown that 5-HT2AR activation can induce visual hallucinations, “mystical” subjective states, and out-of-body experiences (OBEs), and modulate fear circuits. Hallucinatory experiences triggered by serotonin-serotonergic (“pseudo”) hallucinations, induced by hallucinogenic drugs-tend to be “dream-like” with the experiencer having insight (“meta-awareness”) that he is hallucinating, unlike dopaminergic (“psychotic” and “life-like”) hallucinations where such insight is lost. Indeed, hallucinatory experiences during sleep paralysis have the classic features of serotonergic hallucinations, and are strikingly similar to perceptual and subjective states induced by hallucinogenic drugs (e.g., lysergic acid diethylamide [LSD] and psilocybin), i.e., they entail visual hallucinations, mystical experiences, OBEs, and extreme fear reactions. I propose a possible mechanism whereby serotonin could be functionally implicated in generating sleep paralysis hallucinations and fear reactions through 5-HT2AR activity. Moreover, I speculate on the role of 5-HT2C receptors vis-à-vis anxiety and panic during sleep paralysis, and the orbitofrontal cortex-rich with 5-HT2A receptors-in influencing visual pathways during sleep paralysis, and, in effect, hallucinations. Finally, I propose, for the first time, a drug to target sleep paralysis hallucinations and fear reactions, namely the selective 5-HT2AR inverse agonist, pimavanserin. This account implicates gene HTR2A on chromosome 13q as the underlying cause of sleep paralysis hallucinations and could be explored using positron emission tomography.

Jalal, B. (2018). The neuropharmacology of sleep paralysis hallucinations: serotonin 2A activation and a novel therapeutic drug. Psychopharmacology235(11), 3083-3091.,  10.1007/s00213-018-5042-1

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Advances and challenges in neuroimaging studies on the effects of serotonergic hallucinogens: Contributions of the resting brain.

Abstract

The effects of hallucinogenic drugs on the human brain have been studied since the earliest days of neuroimaging in the 1990s. However, approaches are often hard to compare and results are heterogeneous. In this chapter, we summarize studies investigating the effects of hallucinogens on the resting brain, with a special emphasis on replicability and limitations. In previous studies, similarities were observed between psilocybin, LSD, and ayahuasca, with respect to decreases in cerebral blood flow and increases in global functional connectivity in the precuneus and thalamus. Additionally, LSD consistently decreased functional connectivity within distinct resting state networks. Little convergence was observed for connectivity between networks and for blood flow in other brain regions. Although these studies are limited by small sample sizes and might be biased by unspecific drug effects on physiological parameters and the vascular system, current results indicate that neuroimaging could be a useful tool to elucidate the neuronal correlates of hallucinogenic effects.
Müller, F., Liechti, M. E., Lang, U. E., Borgwardt, S., Wilson, M. R., Webb, A., … & Lutz, K. (2018). Advances and challenges in neuroimaging studies on the effects of serotonergic hallucinogens: Contributions of the resting brain. Progress in brain research242, 159-177. 10.1016/bs.pbr.2018.08.004
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Whole-Brain Multimodal Neuroimaging Model Using Serotonin Receptor Maps Explains Non-linear Functional Effects of LSD

Abstract

Understanding the underlying mechanisms of the human brain in health and disease will require models with necessary and sufficient details to explain how function emerges from the underlying anatomy and is shaped by neuromodulation. Here, we provide such a detailed causal explanation using a whole-brain model integrating multimodal imaging in healthy human participants undergoing manipulation of the serotonin system. Specifically, we combined anatomical data from diffusion magnetic resonance imaging (dMRI) and functional magnetic resonance imaging (fMRI) with neurotransmitter data obtained with positron emission tomography (PET) of the detailed serotonin 2A receptor (5-HT2AR) density map. This allowed us to model the resting state (with and without concurrent music listening) and mechanistically explain the functional effects of 5-HT2AR stimulation with lysergic acid diethylamide (LSD) on healthy participants. The whole-brain model used a dynamical mean-field quantitative description of populations of excitatory and inhibitory neurons as well as the associated synaptic dynamics, where the neuronal gain function of the model is modulated by the 5-HT2AR density. The model identified the causative mechanisms for the non-linear interactions between the neuronal and neurotransmitter system, which are uniquely linked to (1) the underlying anatomical connectivity, (2) the modulation by the specific brainwide distribution of neurotransmitter receptor density, and (3) the non-linear interactions between the two. Taking neuromodulatory activity into account when modeling global brain dynamics will lead to novel insights into human brain function in health and disease and opens exciting possibilities for drug discovery and design in neuropsychiatric disorders.

Deco, G., Cruzat, J., Cabral, J., Knudsen, G. M., Carhart-Harris, R. L., Whybrow, P. C., … & Kringelbach, M. L. (2018). Whole-brain multimodal neuroimaging model using serotonin receptor maps explains non-linear functional effects of LSD. Current biology28(19), 3065-3074., 10.1016/j.cub.2018.07.083

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Neurocognitive effects of six ketamine infusions and the association with antidepressant response in patients with unipolar and bipolar depression

Abstract

BACKGROUND:

Ketamine has proven to have rapid, robust antidepressant effects on treatment-resistant depression. However, whether repeated ketamine infusions would cause short-and long-term neurocognitive impairments was not clear. Our aims were to investigate the neurocognitive effects of six ketamine infusions and to examine the association between these infusions and the antidepressant response in patients with unipolar and bipolar depression.

METHODS:

Six intravenous infusions of ketamine (0.5 mg/kg) over a 12-day period were administered to 84 patients with unipolar and bipolar depression. Severity of depressive symptoms and four domains of neurocognition, including speed of processing, working memory, visual learning and verbal learning, were assessed at baseline, one day following the last infusion and again two weeks post-infusion.

RESULTS:

Significant improvements were found on speed of processing ( F=9.344, p<0.001) and verbal learning ( F=5.647, p=0.004) in a linear mixed model. The Sobel test showed significant indirect effects between time and improvement in speed of processing (Sobel test=3.573, p<0.001) as well as improvement in verbal learning (Sobel test=6.649, p<0.001), which were both significantly mediated by change in depressive symptoms. Logistic regression analysis showed ketamine responders had better visual learning at baseline than non-responders (B=0.118, p<0.001).

CONCLUSIONS:

Our findings suggest that neurocognitive function would not deteriorate after six ketamine infusions, while verbal learning and speed of processing improved over 13 days and 26 days of observation, respectively. However, this change was mainly accounted for by improvements in severity of depressive symptoms over time. Greater baseline visual learning predicted an antidepressant response over six ketamine infusions.

Zhou, Y., Zheng, W., Liu, W., Wang, C., Zhan, Y., Li, H., … & Ning, Y. (2018). Neurocognitive effects of six ketamine infusions and the association with antidepressant response in patients with unipolar and bipolar depression. Journal of Psychopharmacology32(10), 1118-1126, 10.1177/0269881118798614
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