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Serotonin transporter-ibogaine complexes illuminate mechanisms of inhibition and transport

April 24, 2019 / Anxiety Disorders / PTSD, Iboga / Ibogaine, Neuroscience, Papers, Publications, Substance Use Disorder / By / , , , , ,

Abstract

The serotonin transporter (SERT) regulates neurotransmitter homeostasis through the sodium- and chloride-dependent recycling of serotonin into presynaptic neurons. Major depression and anxiety disorders are treated using selective serotonin reuptake inhibitors-small molecules that competitively block substrate binding and thereby prolong neurotransmitter action. The dopamine and noradrenaline transporters, together with SERT, are members of the neurotransmitter sodium symporter (NSS) family. The transport activities of NSSs can be inhibited or modulated by cocaine and amphetamines, and genetic variants of NSSs are associated with several neuropsychiatric disorders including attention deficit hyperactivity disorder, autism and bipolar disorder. Studies of bacterial NSS homologues-including LeuT-have shown how their transmembrane helices (TMs) undergo conformational changes during the transport cycle, exposing a central binding site to either side of the membrane. However, the conformational changes associated with transport in NSSs remain unknown. To elucidate structure-based mechanisms for transport in SERT we investigated its complexes with ibogaine, a hallucinogenic natural product with psychoactive and anti-addictive properties. Notably, ibogaine is a non-competitive inhibitor of transport but displays competitive binding towards selective serotonin reuptake inhibitors. Here we report cryo-electron microscopy structures of SERT-ibogaine complexes captured in outward-open, occluded and inward-open conformations. Ibogaine binds to the central binding site, and closure of the extracellular gate largely involves movements of TMs 1b and 6a. Opening of the intracellular gate involves a hinge-like movement of TM1a and the partial unwinding of TM5, which together create a permeation pathway that enables substrate and ion diffusion to the cytoplasm. These structures define the structural rearrangements that occur from the outward-open to inward-open conformations, and provide insight into the mechanism of neurotransmitter transport and ibogaine inhibition.

Coleman, J. A., Yang, D., Zhao, Z., Wen, P. C., Yoshioka, C., Tajkhorshid, E., & Gouaux, E. (2019). Serotonin transporter–ibogaine complexes illuminate mechanisms of inhibition and transport. Nature, 569(7754), 141., 10.1038/s41586-019-1135-1
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Survey of subjective “God encounter experiences”: Comparisons among naturally occurring experiences and those occasioned by the classic psychedelics psilocybin, LSD, ayahuasca, or DMT.

April 23, 2019 / Ayahuasca, DMT, LSD, Mushrooms / Psilocybin, Papers, Psychology, Publications / By / , , , ,

Abstract

Naturally occurring and psychedelic drug-occasioned experiences interpreted as personal encounters with God are well described but have not been systematically compared. In this study, five groups of individuals participated in an online survey with detailed questions characterizing the subjective phenomena, interpretation, and persisting changes attributed to their single most memorable God encounter experience (n = 809 Non-Drug, 1184 psilocybin, 1251 lysergic acid diethylamide (LSD), 435 ayahuasca, and 606 N,N-dimethyltryptamine (DMT)). Analyses of differences in experiences were adjusted statistically for demographic differences between groups. The Non-Drug Group was most likely to choose “God” as the best descriptor of that which was encountered while the psychedelic groups were most likely to choose “Ultimate Reality.” Although there were some other differences between non-drug and the combined psychedelic group, as well as between the four psychedelic groups, the similarities among these groups were most striking. Most participants reported vivid memories of the encounter experience, which frequently involved communication with something having the attributes of being conscious, benevolent, intelligent, sacred, eternal, and all-knowing. The encounter experience fulfilled a priori criteria for being a complete mystical experience in approximately half of the participants. More than two-thirds of those who identified as atheist before the experience no longer identified as atheist afterwards. These experiences were rated as among the most personally meaningful and spiritually significant lifetime experiences, with moderate to strong persisting positive changes in life satisfaction, purpose, and meaning attributed to these experiences. Among the four groups of psychedelic users, the psilocybin and LSD groups were most similar and the ayahuasca group tended to have the highest rates of endorsing positive features and enduring consequences of the experience. Future exploration of predisposing factors and phenomenological and neural correlates of such experiences may provide new insights into religious and spiritual beliefs that have been integral to shaping human culture since time immemorial.
Griffiths, R. R., Hurwitz, E. S., Davis, A. K., Johnson, M. W., & Jesse, R. (2019). Survey of subjective” God encounter experiences”: Comparisons among naturally occurring experiences and those occasioned by the classic psychedelics psilocybin, LSD, ayahuasca, or DMT. PloS one, 14(4), e0214377., https://doi.org/10.1371/journal.pone.0214377
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Survey of subjective "God encounter experiences": Comparisons among naturally occurring experiences and those occasioned by the classic psychedelics psilocybin, LSD, ayahuasca, or DMT.

April 23, 2019 / Ayahuasca, DMT, LSD, Mushrooms / Psilocybin, Papers, Psychology, Publications / By / , , , ,

Abstract

Naturally occurring and psychedelic drug-occasioned experiences interpreted as personal encounters with God are well described but have not been systematically compared. In this study, five groups of individuals participated in an online survey with detailed questions characterizing the subjective phenomena, interpretation, and persisting changes attributed to their single most memorable God encounter experience (n = 809 Non-Drug, 1184 psilocybin, 1251 lysergic acid diethylamide (LSD), 435 ayahuasca, and 606 N,N-dimethyltryptamine (DMT)). Analyses of differences in experiences were adjusted statistically for demographic differences between groups. The Non-Drug Group was most likely to choose “God” as the best descriptor of that which was encountered while the psychedelic groups were most likely to choose “Ultimate Reality.” Although there were some other differences between non-drug and the combined psychedelic group, as well as between the four psychedelic groups, the similarities among these groups were most striking. Most participants reported vivid memories of the encounter experience, which frequently involved communication with something having the attributes of being conscious, benevolent, intelligent, sacred, eternal, and all-knowing. The encounter experience fulfilled a priori criteria for being a complete mystical experience in approximately half of the participants. More than two-thirds of those who identified as atheist before the experience no longer identified as atheist afterwards. These experiences were rated as among the most personally meaningful and spiritually significant lifetime experiences, with moderate to strong persisting positive changes in life satisfaction, purpose, and meaning attributed to these experiences. Among the four groups of psychedelic users, the psilocybin and LSD groups were most similar and the ayahuasca group tended to have the highest rates of endorsing positive features and enduring consequences of the experience. Future exploration of predisposing factors and phenomenological and neural correlates of such experiences may provide new insights into religious and spiritual beliefs that have been integral to shaping human culture since time immemorial.
Griffiths, R. R., Hurwitz, E. S., Davis, A. K., Johnson, M. W., & Jesse, R. (2019). Survey of subjective” God encounter experiences”: Comparisons among naturally occurring experiences and those occasioned by the classic psychedelics psilocybin, LSD, ayahuasca, or DMT. PloS one, 14(4), e0214377., https://doi.org/10.1371/journal.pone.0214377
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Psychedelics as a treatment for disorders of consciousness

April 21, 2019 / Anthropology & Sociology, Mushrooms / Psilocybin, Papers, Psychology, Publications / By / ,

Abstract

Based on its ability to increase brain complexity, a seemingly reliable index of conscious level, we propose testing the capacity of the classic psychedelic, psilocybin, to increase conscious awareness in patients with disorders of consciousness. We also confront the considerable ethical and practical challenges this proposal must address, if this hypothesis is to be directly assessed.

Scott, G., & Carhart-Harris, R. L. (2019). Psychedelics as a treatment for disorders of consciousness. Neuroscience of consciousness, 2019(1), niz003. 10.1093/nc/niz003
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Palliative Nursing and Sacred Medicine: A Holistic Stance on Entheogens, Healing, and Spiritual Care.

April 18, 2019 / Papers, Psychology, Publications / By / , ,

Abstract

The fields of palliative and holistic nursing both maintain a commitment to the care of the whole person, including a focus on spiritual care. Advanced serious illness may pose a plethora of challenges to patients seeking to create meaning and purpose in their lives. The purpose of this article is to introduce scholarly dialogue on the integration of entheogens, medicines that engender an experience of the sacred, into the spiritual and holistic care of patients experiencing advanced serious illness. A brief history of the global use of entheogens as well as a case study are provided. Clinical trials show impressive preliminary findings regarding the healing potential of these medicinal agents. While other professions, such as psychology, pharmacy, and medicine, are disseminating data related to patient outcomes secondary to entheogen administration, the nursing literature has not been involved in raising awareness of such advancements. Research is illustrating their effectiveness in achieving integrative experiences for patients confronting advanced serious illness and their ability to promote presence, introspection, decreased fear, and increased joy and acceptance. Evidence-based knowledge surrounding this potentially sensitive topic is necessary to invite understanding, promote scientific knowledge development, and create healing environments for patients, nurses, and researchers alike.
Rosa, W. E., Hope, S., & Matzo, M. (2019). Palliative Nursing and Sacred Medicine: A Holistic Stance on Entheogens, Healing, and Spiritual Care. Journal of Holistic Nursing, 37(1), 100-106, https://doi.org/10.1177/0898010118770302
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A single inhalation of vapor from dried toad secretion containing 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) in a naturalistic setting is related to sustained enhancement of satisfaction with life, mindfulness-related capacities, and a decrement of psychopathological symptoms

September 17, 2024 / 5-MeO-DMT, Anxiety Disorders / PTSD, Depressive Disorders, Papers, Psychology, Publications, Substance / By / , , , , ,

Abstract

BACKGROUND: 5-methoxy-N,N-dimethyltryptamine (hereinafter referred to as 5-MeO-DMT) is a psychedelic substance found in the secretion from the parotoid glands of the Bufo alvarius toad. Inhalation of vapor from toad secretion containing 5-MeO-DMT has become popular in naturalistic settings as a treatment of mental health problems or as a means for spiritual exploration. However, knowledge of the effects of 5-MeO-DMT in humans is limited.
AIMS: The first objective of this study was to assess sub-acute and long-term effects of inhaling vapor from dried toad secretion containing 5-MeO-DMT on affect and cognition. The second objective was to assess whether any changes were associated with the psychedelic experience.
METHODS: Assessments at baseline, within 24 h and 4 weeks following intake, were made in 42 individuals who inhaled vapor from dried toad secretion at several European locations.
RESULTS: Relative to baseline, ratings of satisfaction with life and convergent thinking significantly increased right after intake and were maintained at follow-up 4 weeks later. Ratings of mindfulness also increased over time and reached statistical significance at 4 weeks. Ratings of depression, anxiety, and stress decreased after the session, and reached significance at 4 weeks. Participants that experienced high levels of ego dissolution or oceanic boundlessness during the session displayed higher ratings of satisfaction with life and lower ratings of depression and stress.
CONCLUSION: A single inhalation of vapor from dried toad secretion containing 5-MeO-DMT produces sub-acute and long-term changes in affect and cognition in volunteers. These results warrant exploratory research into therapeutic applications of 5-MeO-DMT.
Uthaug, M. V., Lancelotta, R., van Oorsouw, K., Kuypers, K. P. C., Mason, N., Rak, J., … & Ramaekers, J. G. (2019). A single inhalation of vapor from dried toad secretion containing 5-methoxy-N, N-dimethyltryptamine (5-MeO-DMT) in a naturalistic setting is related to sustained enhancement of satisfaction with life, mindfulness-related capacities, and a decrement of psychopathological symptoms. Psychopharmacology, 236(9), 2653-2666., https://doi.org/10.1007/s00213-019-05236-w
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A single inhalation of vapor from dried toad secretion containing 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) in a naturalistic setting is related to sustained enhancement of satisfaction with life, mindfulness-related capacities, and a decrement of psychopathological symptoms.

April 13, 2019 / Anxiety Disorders / PTSD, Depressive Disorders, DMT, Papers, Psychology, Publications / By / , , , , , ,

Abstract

BACKGROUND:
5-methoxy-N,N-dimethyltryptamine (hereinafter referred to as 5-MeO-DMT) is a psychedelic substance found in the secretion from the parotoid glands of the Bufo alvarius toad. Inhalation of vapor from toad secretion containing 5-MeO-DMT has become popular in naturalistic settings as a treatment of mental health problems or as a means for spiritual exploration. However, knowledge of the effects of 5-MeO-DMT in humans is limited.
AIMS:
The first objective of this study was to assess sub-acute and long-term effects of inhaling vapor from dried toad secretion containing 5-MeO-DMT on affect and cognition. The second objective was to assess whether any changes were associated with the psychedelic experience.
METHODS:
Assessments at baseline, within 24 h and 4 weeks following intake, were made in 42 individuals who inhaled vapor from dried toad secretion at several European locations.
RESULTS:
Relative to baseline, ratings of satisfaction with life and convergent thinking significantly increased right after intake and were maintained at follow-up 4 weeks later. Ratings of mindfulness also increased over time and reached statistical significance at 4 weeks. Ratings of depression, anxiety, and stress decreased after the session, and reached significance at 4 weeks. Participants that experienced high levels of ego dissolution or oceanic boundlessness during the session displayed higher ratings of satisfaction with life and lower ratings of depression and stress.
CONCLUSION:
A single inhalation of vapor from dried toad secretion containing 5-MeO-DMT produces sub-acute and long-term changes in affect and cognition in volunteers. These results warrant exploratory research into therapeutic applications of 5-MeO-DMT.

 
Uthaug, M. V., Lancelotta, R., van Oorsouw, K., Kuypers, K. P. C., Mason, N., Rak, J., … & Páleníček, T. (2019). A single inhalation of vapor from dried toad secretion containing 5-methoxy-N, N-dimethyltryptamine (5-MeO-DMT) in a naturalistic setting is related to sustained enhancement of satisfaction with life, mindfulness-related capacities, and a decrement of psychopathological symptoms. Psychopharmacology, 1-14., https://doi.org/10.1007/s00213-019-05236-w
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Cytochrome P450 enzymes contribute to the metabolism of LSD to nor-LSD and 2-oxo-3-hydroxy-LSD: Implications for clinical LSD use

April 11, 2019 / LSD, Neuroscience, Papers, Pharmacology & Chemistry / By / , , , ,

Abstract

In recent years, experimental research on lysergic acid diethylamide (LSD) in humans has gained new momentum. In humans, LSD is metabolized rapidly into several metabolites but knowledge of the involved metabolizing enzymes is limited. The aim of the current study was to identify the cytochrome P450 (CYP) isoforms involved in the metabolism of LSD to 6-norlysergic acid diethylamide (nor-LSD) and 2-oxo-3-hydroxy-LSD (O-H-LSD) in vitro, in order to evaluate potential effects of enzyme polymorphisms or prescription drugs on LSD pharmacokinetics. Additionally, interactions of LSD and both metabolites with 5-hydroxytryptamine (5-HT) receptors were assessed. LSD was incubated with human liver microsomes over 4 h and the production of nor-LSD and O-H-LSD was quantified by liquid chromatography tandem mass spectrometry. Metabolism was inhibited by the addition of specific CYP inhibitors. Additionally, recombinant CYPs were used to verify the inhibition results obtained with microsomes and induction of metabolism was investigated in human hepatocyte-derived cells. Radioligand binding and calcium mobilization assays were used to determine 5-HT receptor affinities and activities, respectively. Human liver microsomes displayed minor metabolite formation (<1% metabolized) over 4 h. CYP2D6, 2E1, and 3A4 significantly contributed to the formation of nor-LSD, and CYP1A2, 2C9, 2E1, and 3A4 were significantly involved in the formation of O-H-LSD. These findings could be verified using recombinant CYPs. Enzyme induction with rifampicin distinctly increased the formation of both metabolites, whereas treatment with omeprazole only slightly increased formation of nor-LSD. LSD and nor-LSD were pharmacologically active at the 5-HT1A, 5-HT2A, 5-HT2B, and 5-HT2C receptors. Nor-LSD mainly differed from the parent compound by having a lower affinity to the 5-HT2C receptor. O-H-LSD displayed substantially weaker affinity and activity at serotonergic receptors in comparison to LSD. To conclude, human liver microsomes converted only small amounts of LSD to nor-LSD and O-H-LSD but several CYPs significantly contributed. Genetic polymorphisms and drug interactions could therefore influence pharmacokinetics and pharmacodynamics of LSD. Nor-LSD likely has hallucinogenic activity similar to LSD, whereas O-H-LSD is inactive. Drug-drug interaction studies in humans are required to further assess the clinical relevance of these findings.

Luethi, D., Hoener, M. C., Krähenbühl, S., Liechti, M. E., & Duthaler, U. (2019). Cytochrome P450 enzymes contribute to the metabolism of LSD to nor-LSD and 2-oxo-3-hydroxy-LSD: Implications for clinical LSD use. Biochemical pharmacology, 164, 129-138., 10.1016/j.bcp.2019.04.013
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Ibogaine and Subjective Experience: Transformative States and Psychopharmacotherapy in the Treatment of Opioid Use Disorder

April 9, 2019 / Iboga / Ibogaine, Papers, Psychology, Publications, Substance Use Disorder / By / , ,

Abstract

This article examines the therapeutic potential of ibogaine, a powerful oneiric alkaloid derived from Tabernanthe iboga, through exploring the subjective experiences of 44 participants from two observational treatment studies for opioid use disorder. Following treatment with ibogaine HCl, the participants (Mexico, n = 30; New Zealand, n = 14) completed the States of Consciousness Questionnaire (SCQ) to quantify the magnitude of their psychotropic experience. Participants were asked to provide written transcripts of their experiences, with those supplied being analyzed thematically through an iterative process, to produce a set of coded themes. Mean SCQ scores in many domains exceeded 0.6, the cutoff score for a “complete mystical experience,” with 43% of participants achieving this in more than five of seven domains. Qualitative data described multiple phenomenological themes, including auditory and visual phenomena. Ibogaine’s strong oneiric action promoted cyclic visions leading to confronting realizations involving remorse and regret for participants’ actions towards others, but also release from feelings of guilt and worthlessness. Many participants reported feeling a sense of spiritual transformation. We propose that the reported experiences support the meaningfulness of ibogaine’s oneiric effects as a discrete element in its capacity for healing, which is distinct from pharmacological actions associated with reduced withdrawal and craving.

Brown, T. K., Noller, G. E., & Denenberg, J. O. (2019). Ibogaine and Subjective Experience: Transformative States and Psychopharmacotherapy in the Treatment of Opioid Use Disorder. Journal of psychoactive drugs, 1-11., https://doi.org/10.1080/02791072.2019.1598603
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Effects of the Psychedelic Amphetamine MDA (3,4-Methylenedioxyamphetamine) in Healthy Volunteers.

April 9, 2019 / MDMA, Papers, Psychology, Publications / By / , , , , , ,

Abstract

Entactogens such as 3,4-Methylenedioxymethamphetamine (MDMA, “molly”, “ecstasy”) appear to have unusual, potentially therapeutic, emotional effects. Understanding their mechanisms can benefit from clinical experiments with related drugs. Yet the first known drug with such properties, 3,4-Methylenedioxyamphetamine (MDA), remains poorly studied and its pharmacokinetics in humans are unknown. We conducted a within-subjects, double-blind, placebo-controlled study of 1.4 mg/kg oral racemic MDA and compared results to those from our prior similar studies with 1.5 mg/kg oral racemic MDMA. MDA was well-tolerated by participants. MDA induced robust increases in heart rate and blood pressure and increased cortisol and prolactin to a similar degree as MDMA. MDA self-report effects shared features with MDMA as well as with classical psychedelics. MDA self-report effects lasted longer than those of MDMA, with MDA effects remaining elevated at 8 h while MDMA effects resolved by 6 h. Cmax and AUC0-∞ for MDA were 229 ± 39 (mean ± SD) and 3636 ± 958 µg/L for MDA and 92 ± 61 and 1544 ± 741 µg/L for the metabolite 4-hydroxy-3-methoxyamphetamine (HMA). There was considerable between-subject variation in MDA/HMA ratios. The similarity of MDA and MDMA pharmacokinetics suggests that the greater duration of MDA effects is due to pharmacodynamics rather than pharmacokinetics.
Baggott, M. J., Garrison, K. J., Coyle, J. R., Galloway, G. P., Barnes, A. J., Huestis, M. A., & Mendelson, J. E. (2019). Effects of the psychedelic amphetamine MDA (3, 4-methylenedioxyamphetamine) in healthy volunteers. Journal of psychoactive drugs, 1-10., https://doi.org/10.1080/02791072.2019.1593560
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