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Shinozuka K, Tabaac BJ, Arenas A, Beutler BD, Cherian K, Evans VD, Fasano C, Muir OS. Psychedelic Therapy: A Primer for Primary Care Clinicians-N,N-Dimethyltryptamine and Ayahuasca. Am J Ther 2024; 31:e112-e120. [PMID: 38518268 DOI: 10.1097/mjt.0000000000001725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/24/2024]
Abstract
BACKGROUND N,N-dimethyltryptamine (DMT) is a naturally occurring serotonergic psychedelic found in natural plants around the globe. As the main psychoactive component in ayahuasca, which also contains monoamine oxidase inhibitors, DMT has been consumed as plant-based brew by indigenous peoples for centuries. Further research is required to delineate the therapeutic utility of DMT. AREAS OF UNCERTAINTY Although previous research has shown that DMT is synthesized endogenously, it may not be produced at physiologically relevant concentrations. Additionally, the phenomenological similarities between the DMT-induced state and near-death experiences led to the popular hypothesis that endogenous DMT is released during the dying process. However, this hypothesis continues to be debated. Generally, DMT and ayahuasca seem to be physiologically and psychiatrically safe, although ayahuasca is known to cause transient vomiting. THERAPEUTIC ADVANCES A double-blind, randomized controlled trial showed that, within 1 week, ayahuasca causes remission in 36% of patients with treatment-resistant depression. According to top-line results from a recent phase IIa trial, 57% of patients with major depressive disorder experienced remission 12 weeks after receiving a single intravenous dose of DMT. LIMITATIONS There has only been a single published double-blind randomized controlled trial on ayahuasca and 2 on DMT. All clinical trials have had small sample sizes (≤34 participants). DMT requires further research to understand its therapeutic and clinical potential as a psychedelic. CONCLUSIONS Preliminary evidence indicates that ayahuasca and DMT may be more effective than existing antidepressants for treating major depressive disorder and treatment-resistant depression.
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Affiliation(s)
- Kenneth Shinozuka
- Centre for Eudaimonia and Human Flourishing, University of Oxford, Oxford, United Kingdom
- Department of Psychiatry, University of Oxford, Oxford, United Kingdom
| | - Burton J Tabaac
- University of Nevada, Reno School of Medicine, Reno, NV
- Department of Neurology, Carson Tahoe Health, Carson City, NV
| | - Alejandro Arenas
- Department of Anesthesiology, University of Washington School of Medicine, Seattle, WA
| | - Bryce D Beutler
- University of Southern California, Keck School of Medicine, Los Angeles, CA
| | - Kirsten Cherian
- Department of Psychiatry & Behavioral Sciences, Stanford University, Palo Alto, CA
| | - Viviana D Evans
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY
| | | | - Owen S Muir
- Fermata Health, Brooklyn, New York, NY; and
- Acacia Clinics, Sunnyvale, CA
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Lawrence DW, DiBattista AP, Timmermann C. N, N-Dimethyltryptamine (DMT)-Occasioned Familiarity and the Sense of Familiarity Questionnaire (SOF-Q). J Psychoactive Drugs 2023:1-13. [PMID: 37428989 DOI: 10.1080/02791072.2023.2230568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 03/30/2023] [Accepted: 04/13/2023] [Indexed: 07/12/2023]
Abstract
This study investigated the sense of familiarity attributed to N, N-dimethyltryptamine (DMT) experiences. 227 naturalistic inhaled-DMT experiences reporting a sense of familiarity were included. No experiences referenced a previous DMT or psychedelic experience as the source of the familiarity. A high prevalence of concomitant features discordant from ordinary consciousness were identified: features of a mystical experience (97.4%), ego-dissolution (16.3%), and a "profound experience of death" (11.0%). The Sense of Familiarity Questionnaire (SOF-Q) was developed assessing 19 features of familiarity across 5 themes: (1) Familiarity with the Feeling, Emotion, or Knowledge Gained; (2) Familiarity with the Place, Space, State, or Environment; (3) Familiarity with the Act of Going Through the Experience; (4) Familiarity with Transcendent Features; and (5) Familiarity Imparted by an Entity Encounter. Bayesian latent class modeling yielded two stable classes of participants who shared similar SOF-Q responses. Class 1 participants responded, "yes" more often for items within "Familiarity Imparted by an Entity Encounter" and "Familiarity with the Feeling, Emotion, or Knowledge Gained." Results catalogued features of the sense of familiarity imparted by DMT, which appears to be non-referential to a previous psychedelic experience. Findings provide insights into the unique and enigmatic familiarity reported during DMT experiences and offer a foundation for further exploration into this intriguing phenomenon.
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Affiliation(s)
- David Wyndham Lawrence
- Department of Family & Community Medicine, Faculty of Medicine, University of Toronto, Toronto, Canada
- Mount Sinai Hospital, Sinai Health System, Toronto, Canada
- Faculty of Kinesiology & Physical Education, University of Toronto, Toronto, Canada
| | - Alex P DiBattista
- Faculty of Kinesiology & Physical Education, University of Toronto, Toronto, Canada
| | - Christopher Timmermann
- Centre for Psychedelic Research, Division of Psychiatry, Department of Brain Sciences, Imperial College London, London, UK
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Molecular Pathways of the Therapeutic Effects of Ayahuasca, a Botanical Psychedelic and Potential Rapid-Acting Antidepressant. Biomolecules 2022; 12:biom12111618. [DOI: 10.3390/biom12111618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 10/27/2022] [Accepted: 10/29/2022] [Indexed: 11/06/2022] Open
Abstract
Ayahuasca is a psychoactive brew traditionally used in indigenous and religious rituals and ceremonies in South America for its therapeutic, psychedelic, and entheogenic effects. It is usually prepared by lengthy boiling of the leaves of the bush Psychotria viridis and the mashed stalks of the vine Banisteriopsis caapi in water. The former contains the classical psychedelic N,N-dimethyltryptamine (DMT), which is thought to be the main psychoactive alkaloid present in the brew. The latter serves as a source for β-carbolines, known for their monoamine oxidase-inhibiting (MAOI) properties. Recent preliminary research has provided encouraging results investigating ayahuasca’s therapeutic potential, especially regarding its antidepressant effects. On a molecular level, pre-clinical and clinical evidence points to a complex pharmacological profile conveyed by the brew, including modulation of serotoninergic, glutamatergic, dopaminergic, and endocannabinoid systems. Its substances also interact with the vesicular monoamine transporter (VMAT), trace amine-associated receptor 1 (TAAR1), and sigma-1 receptors. Furthermore, ayahuasca’s components also seem to modulate levels of inflammatory and neurotrophic factors beneficially. On a biological level, this translates into neuroprotective and neuroplastic effects. Here we review the current knowledge regarding these molecular interactions and how they relate to the possible antidepressant effects ayahuasca seems to produce.
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Abstract
N,N-dimethyltryptamine (DMT) is a potent psychedelic naturally produced by many plants and animals, including humans. Whether or not DMT is significant to mammalian physiology, especially within the central nervous system, is a debate that started in the early 1960s and continues to this day. This review integrates historical and recent literature to clarify this issue, giving special attention to the most controversial subjects of DMT's biosynthesis, its storage in synaptic vesicles and the activation receptors like sigma-1. Less discussed topics, like DMT's metabolic regulation or the biased activation of serotonin receptors, are highlighted. We conclude that most of the arguments dismissing endogenous DMT's relevance are based on obsolete data or misleading assumptions. Data strongly suggest that DMT can be relevant as a neurotransmitter, neuromodulator, hormone and immunomodulator, as well as being important to pregnancy and development. Key experiments are addressed to definitely prove what specific roles DMT plays in mammalian physiology.
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Affiliation(s)
- Javier Hidalgo Jiménez
- ICEERS Foundation (International Center for Ethnobotanical Education, Research and Services), Barcelona, Spain
| | - José Carlos Bouso
- ICEERS Foundation (International Center for Ethnobotanical Education, Research and Services), Barcelona, Spain
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Lawrence DW, Carhart-Harris R, Griffiths R, Timmermann C. Phenomenology and content of the inhaled N, N-dimethyltryptamine (N, N-DMT) experience. Sci Rep 2022; 12:8562. [PMID: 35610230 PMCID: PMC9130218 DOI: 10.1038/s41598-022-11999-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 04/28/2022] [Indexed: 11/25/2022] Open
Abstract
Understanding the phenomenology and content of the inhaled N, N, dimethyltryptamine (N, N-DMT) experience is critical to facilitate and support ongoing research and therapeutic models targeting mental health conditions and central nervous system pathology. A qualitative analysis was conducted of all N, N-DMT experiences posted to the r/DMT Reddit community over a 10-year period from 2009 to 2018. A total of 3778 experiences from 3305 posts were included in this study. A median dose of N, N-DMT of 40.0 mg [interquartile range (IQR), 27.5 to 50.0] and a median experience duration of 10 min (IQR, 5.0 to 15.0) were identified. The most common somatic effects were somaesthesias (n = 1415, 37.5%) and an auditory ringing (n = 583, 15.4%). Visualizations predominantly consisted of fractals, shapes, patterns (n = 1231, 32.6%) and vivid colours (n = 953, 25.2%). Entity encounters were reported in 45.5% (n = 1719) of the experiences and involved predominantly a feminine phenotype (n = 416, 24.2%); deities (n = 293, 17.0%); aliens (n = 281, 16.3%); creature-based entities (n = 158, 9.2%, including reptilian and insectoid beings); mythological beings (n = 144, 8.4%, including machine elves); and jesters (n = 112, 6.5%). Entity interactions were predominantly positive (n = 600, 34.9% of encounters) involving benevolent, comforting, protecting, or outwardly caring interactions. A companion-type, pedagogical, or guide-type interaction was identified 32.4% of encounters (n = 557). Common typology, architecture, and structural features of the "DMT world" included descriptions of alternate or higher dimensions (n = 952, 25.2%); rooms [n = 582, 15.4%, including the "waiting room" (n = 105, 2.8%)], and a tunnel (n = 390, 10.3%). Features of mystical and ego-dissolution experiences were common. Additional rewarding aspects were identified, including a sense of familiarity and the acceptance/removal of the fear of death. Challenging and difficult responses were less frequent but also documented. Statements of profundity were identified in 232 experiences (6.1%), including pronouncing the experience or an aspect of the experience as the most "beautiful" or feeling the most "beautiful" of their life (n = 47, 1.2%). This study identified common phenomenological themes and content of naturalistic inhaled N, N-DMT experiences. Major thematic domains included (1) physical and somatic experiences; (2) visualizations and imagery; (3) entity encounters including entity phenotype, descriptors, attributes, disposition, and characteristics of the interaction; (4) typology, architectural features, structural characteristics, and scenery of the "DMT world"; (5) alerations in consciousness (including mystical experiences, out-of-body experiences, and ego-dissolution); (6) emotional responses (including positive, rewarding, difficult, and challenging); and (7) statements of profundity.
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Affiliation(s)
- David Wyndham Lawrence
- Department of Family & Community Medicine, Faculty of Medicine, University of Toronto, Toronto, Canada.
- Mount Sinai Hospital, Sinai Health System, 600 University Avenue, Toronto, M5G 1X5, Canada.
- Faculty of Kinesiology & Physical Education, University of Toronto, Toronto, Canada.
| | - Robin Carhart-Harris
- Centre for Psychedelic Research, Division of Psychiatry, Department of Brain Sciences, Imperial College London, London, UK
- Psychedelics Division, Neuroscape, Department of Neurology, University of California, San Francisco, CA, USA
| | - Roland Griffiths
- Departments of Psychiatry and Neuroscience, Center for Psychedelic and Consciousness Research, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Christopher Timmermann
- Centre for Psychedelic Research, Division of Psychiatry, Department of Brain Sciences, Imperial College London, London, UK
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Mahmood D, Alenezi SK, Anwar MJ, Azam F, Qureshi KA, Jaremko M. New Paradigms of Old Psychedelics in Schizophrenia. Pharmaceuticals (Basel) 2022; 15:ph15050640. [PMID: 35631466 PMCID: PMC9147282 DOI: 10.3390/ph15050640] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 04/08/2022] [Accepted: 05/17/2022] [Indexed: 11/16/2022] Open
Abstract
Psychedelics such as lysergic acid diethylamide (LSD), psilocybin (magic mushrooms), and mescaline exhibit intense effects on the human brain and behaviour. In recent years, there has been a surge in studies investigating these drugs because clinical studies have shown that these once banned drugs are well tolerated and efficacious in medically supervised low doses called microdosing. Psychedelics have demonstrated efficacy in treating neuropsychiatric maladies such as difficult to treat anxiety, depression, mood disorders, obsessive compulsive disorders, suicidal ideation, posttraumatic stress disorder, and also in treating substance use disorders. The primary mode of action of psychedelics is activation of serotonin 5-HT2A receptors affecting cognition and brain connectivity through the modulation of several downstream signalling pathways via complex molecular mechanisms. Some atypical antipsychotic drugs (APDs) primarily exhibit pharmacological actions through 5-HT2A receptors, which are also the target of psychedelic drugs. Psychedelic drugs including the newer second generation along with the glutamatergic APDs are thought to mediate pharmacological actions through a common pathway, i.e., a complex serotonin-glutamate receptor interaction in cortical neurons of pyramidal origin. Furthermore, psychedelic drugs have been reported to act via a complex interplay between 5HT2A, mGlu2/3, and NMDA receptors to mediate neurobehavioral and pharmacological actions. Findings from recent studies have suggested that serotoninergic and glutamatergic neurotransmissions are very closely connected in producing pharmacological responses to psychedelics and antipsychotic medication. Emerging hypotheses suggest that psychedelics work through brain resetting mechanisms. Hence, there is a need to dig deeply into psychedelic neurobiology to uncover how psychedelics could best be used as scientific tools to benefit psychiatric disorders including schizophrenia.
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Affiliation(s)
- Danish Mahmood
- Department of Pharmacology & Toxicology, Unaizah College of Pharmacy, Qassim University, Unaizah 51911, Saudi Arabia; (S.K.A.); (M.J.A.)
- Correspondence: or
| | - Sattam K. Alenezi
- Department of Pharmacology & Toxicology, Unaizah College of Pharmacy, Qassim University, Unaizah 51911, Saudi Arabia; (S.K.A.); (M.J.A.)
| | - Md. Jamir Anwar
- Department of Pharmacology & Toxicology, Unaizah College of Pharmacy, Qassim University, Unaizah 51911, Saudi Arabia; (S.K.A.); (M.J.A.)
| | - Faizul Azam
- Department of Pharmaceutical Chemistry & Pharmacognosy, Unaizah College of Pharmacy, Qassim University, Unaizah 51911, Saudi Arabia;
| | - Kamal A. Qureshi
- Department of Pharmaceutics, Unaizah College of Pharmacy, Qassim University, Unaizah 51911, Saudi Arabia;
| | - Mariusz Jaremko
- Smart-Health Initiative (SHI) and Red Sea Research Center (RSRC), Division of Biological and Environmental Sciences and Engineering (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Saudi Arabia;
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Administration of N,N-dimethyltryptamine (DMT) in psychedelic therapeutics and research and the study of endogenous DMT. Psychopharmacology (Berl) 2022; 239:1749-1763. [PMID: 35064294 PMCID: PMC8782705 DOI: 10.1007/s00213-022-06065-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 01/11/2022] [Indexed: 12/20/2022]
Abstract
As with all drugs, the route, form, and/or dose of a substance administered or applied can play a defining role in its overall pharmacology and use as a therapeutic. This review will focus on these factors as they relate to the psychedelic N,N-dimethyltryptamine (DMT). It will examine the positive and negative aspects of different formulations and routes of administration of DMT and the observed effects from such administrations in the form of ayahuasca teas; oral "pharmahuasca"; injections by intravenous (IV) and intramuscular (IM) routes; inhalation, insufflation; and other routes; and high-dose, low-dose, and "micro-dose" effects. The review will consider possible oral route of administration alternatives that would not require concomitant use of a monoamine oxidase inhibitor. The review will then address the current research findings for DMT from in vivo and in vitro studies as well as the possibility that these findings may be revealing the role of endogenous DMT in normal brain function.
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Szabó Í, Varga VÉ, Dvorácskó S, Farkas AE, Körmöczi T, Berkecz R, Kecskés S, Menyhárt Á, Frank R, Hantosi D, Cozzi NV, Frecska E, Tömböly C, Krizbai IA, Bari F, Farkas E. N,N-Dimethyltryptamine attenuates spreading depolarization and restrains neurodegeneration by sigma-1 receptor activation in the ischemic rat brain. Neuropharmacology 2021; 192:108612. [PMID: 34023338 DOI: 10.1016/j.neuropharm.2021.108612] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 04/23/2021] [Accepted: 05/13/2021] [Indexed: 12/19/2022]
Abstract
Dimethyltryptamine (DMT), an endogenous ligand of sigma-1 receptors (Sig-1Rs), acts against systemic hypoxia, but whether DMT may prevent cerebral ischemic injury is unexplored. Here global forebrain ischemia was created in anesthetized rats and aggravated with the induction of spreading depolarizations (SDs) and subsequent short hypoxia before reperfusion. Drugs (DMT, the selective Sig-1R agonist PRE-084, the Sig-1R antagonist NE-100, or the serotonin receptor antagonist asenapine) were administered intravenously alone or in combination while physiological variables and local field potential from the cerebral cortex was recorded. Neuroprotection and the cellular localization of Sig-1R were evaluated with immunocytochemistry. Plasma and brain DMT content was measured by 2D-LC-HRMS/MS. The affinity of drugs for cerebral Sig-1R was evaluated with a radioligand binding assay. Both DMT and PRE-084 mitigated SDs, counteracted with NE-100. Further, DMT attenuated SD when co-administered with asenapine, compared to asenapine alone. DMT reduced the number of apoptotic and ferroptotic cells and supported astrocyte survival. The binding affinity of DMT to Sig-1R matched previously reported values. Sig-1Rs were associated with the perinuclear cytoplasm of neurons, astrocytes and microglia, and with glial processes. According to these data, DMT may be considered as adjuvant pharmacological therapy in the management of acute cerebral ischemia.
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Affiliation(s)
- Írisz Szabó
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged; Korányi Fasor 9, Szeged, 6720, Hungary.
| | - Viktória É Varga
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged; Korányi Fasor 9, Szeged, 6720, Hungary.
| | - Szabolcs Dvorácskó
- Laboratory of Chemical Biology, Institute of Biochemistry, Biological Research Centre, Temesvári Krt 62, Szeged, 6726, Hungary; Department of Medical Chemistry, Faculty of Medicine, University of Szeged, Dóm Tér 8, Szeged, 6720, Hungary.
| | - Attila E Farkas
- Neurovascular Unit Research Group, Molecular Neurobiology Research Unit, Institute of Biophysics, Biological Research Centre, Temesvári Krt 62, Szeged, 6726, Hungary.
| | - Tímea Körmöczi
- Department of Medical Chemistry, Faculty of Medicine, University of Szeged, Dóm Tér 8, Szeged, 6720, Hungary; Institute of Pharmaceutical Analysis, Faculty of Pharmacy, University of Szeged, Somogyi U 4, Szeged, 6720, Hungary.
| | - Róbert Berkecz
- Department of Medical Chemistry, Faculty of Medicine, University of Szeged, Dóm Tér 8, Szeged, 6720, Hungary; Institute of Pharmaceutical Analysis, Faculty of Pharmacy, University of Szeged, Somogyi U 4, Szeged, 6720, Hungary.
| | - Szilvia Kecskés
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged; Korányi Fasor 9, Szeged, 6720, Hungary.
| | - Ákos Menyhárt
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged; Korányi Fasor 9, Szeged, 6720, Hungary.
| | - Rita Frank
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged; Korányi Fasor 9, Szeged, 6720, Hungary.
| | - Dóra Hantosi
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged; Korányi Fasor 9, Szeged, 6720, Hungary.
| | - Nicholas V Cozzi
- Neuropharmacology Laboratory, University of Wisconsin School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA; Alexander Shulgin Research Institute, 1483 Shulgin Road, Lafayette, CA, 94549, USA.
| | - Ede Frecska
- Department of Psychiatry, Faculty of Medicine, University of Debrecen, Nagyerdei Krt 94, Debrecen, 4032, Hungary.
| | - Csaba Tömböly
- Laboratory of Chemical Biology, Institute of Biochemistry, Biological Research Centre, Temesvári Krt 62, Szeged, 6726, Hungary.
| | - István A Krizbai
- Neurovascular Unit Research Group, Molecular Neurobiology Research Unit, Institute of Biophysics, Biological Research Centre, Temesvári Krt 62, Szeged, 6726, Hungary; Institute of Life Sciences, UVVG, 94 Bulevardul Revoluției, Arad, 310025, Romania.
| | - Ferenc Bari
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged; Korányi Fasor 9, Szeged, 6720, Hungary.
| | - Eszter Farkas
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged; Korányi Fasor 9, Szeged, 6720, Hungary.
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Cumming P, Scheidegger M, Dornbierer D, Palner M, Quednow BB, Martin-Soelch C. Molecular and Functional Imaging Studies of Psychedelic Drug Action in Animals and Humans. Molecules 2021; 26:2451. [PMID: 33922330 PMCID: PMC8122807 DOI: 10.3390/molecules26092451] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 04/15/2021] [Accepted: 04/19/2021] [Indexed: 12/19/2022] Open
Abstract
Hallucinogens are a loosely defined group of compounds including LSD, N,N-dimethyltryptamines, mescaline, psilocybin/psilocin, and 2,5-dimethoxy-4-methamphetamine (DOM), which can evoke intense visual and emotional experiences. We are witnessing a renaissance of research interest in hallucinogens, driven by increasing awareness of their psychotherapeutic potential. As such, we now present a narrative review of the literature on hallucinogen binding in vitro and ex vivo, and the various molecular imaging studies with positron emission tomography (PET) or single photon emission computer tomography (SPECT). In general, molecular imaging can depict the uptake and binding distribution of labelled hallucinogenic compounds or their congeners in the brain, as was shown in an early PET study with N1-([11C]-methyl)-2-bromo-LSD ([11C]-MBL); displacement with the non-radioactive competitor ketanserin confirmed that the majority of [11C]-MBL specific binding was to serotonin 5-HT2A receptors. However, interactions at serotonin 5HT1A and other classes of receptors and pleotropic effects on second messenger pathways may contribute to the particular experiential phenomenologies of LSD and other hallucinogenic compounds. Other salient aspects of hallucinogen action include permeability to the blood-brain barrier, the rates of metabolism and elimination, and the formation of active metabolites. Despite the maturation of radiochemistry and molecular imaging in recent years, there has been only a handful of PET or SPECT studies of radiolabeled hallucinogens, most recently using the 5-HT2A/2C agonist N-(2[11CH3O]-methoxybenzyl)-2,5-dimethoxy- 4-bromophenethylamine ([11C]Cimbi-36). In addition to PET studies of target engagement at neuroreceptors and transporters, there is a small number of studies on the effects of hallucinogenic compounds on cerebral perfusion ([15O]-water) or metabolism ([18F]-fluorodeoxyglucose/FDG). There remains considerable scope for basic imaging research on the sites of interaction of hallucinogens and their cerebrometabolic effects; we expect that hybrid imaging with PET in conjunction with functional magnetic resonance imaging (fMRI) should provide especially useful for the next phase of this research.
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Affiliation(s)
- Paul Cumming
- Department of Nuclear Medicine, Bern University Hospital, CH-3010 Bern, Switzerland
- School of Psychology and Counselling, Queensland University of Technology, Brisbane 4059, Australia
| | - Milan Scheidegger
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital of the University of Zurich, CH-8032 Zurich, Switzerland; (M.S.); (D.D.); (B.B.Q.)
| | - Dario Dornbierer
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital of the University of Zurich, CH-8032 Zurich, Switzerland; (M.S.); (D.D.); (B.B.Q.)
| | - Mikael Palner
- Odense Department of Clinical Research, University of Southern Denmark, DK-5000 Odense, Denmark;
- Department of Nuclear Medicine, Odense University Hospital, DK-5000 Odense, Denmark
- Neurobiology Research Unit, Copenhagen University Hospital, DK-2100 Copenhagen, Denmark
| | - Boris B. Quednow
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital of the University of Zurich, CH-8032 Zurich, Switzerland; (M.S.); (D.D.); (B.B.Q.)
- Neuroscience Center Zurich, University of Zurich and Swiss Federal Institute of Technology Zurich, CH-8058 Zurich, Switzerland
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Brito-da-Costa AM, Dias-da-Silva D, Gomes NGM, Dinis-Oliveira RJ, Madureira-Carvalho Á. Toxicokinetics and Toxicodynamics of Ayahuasca Alkaloids N, N-Dimethyltryptamine (DMT), Harmine, Harmaline and Tetrahydroharmine: Clinical and Forensic Impact. Pharmaceuticals (Basel) 2020; 13:ph13110334. [PMID: 33114119 PMCID: PMC7690791 DOI: 10.3390/ph13110334] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 10/16/2020] [Accepted: 10/20/2020] [Indexed: 12/11/2022] Open
Abstract
Ayahuasca is a hallucinogenic botanical beverage originally used by indigenous Amazonian tribes in religious ceremonies and therapeutic practices. While ethnobotanical surveys still indicate its spiritual and medicinal uses, consumption of ayahuasca has been progressively related with a recreational purpose, particularly in Western societies. The ayahuasca aqueous concoction is typically prepared from the leaves of the N,N-dimethyltryptamine (DMT)-containing Psychotria viridis, and the stem and bark of Banisteriopsis caapi, the plant source of harmala alkaloids. Herein, the toxicokinetics and toxicodynamics of the psychoactive DMT and harmala alkaloids harmine, harmaline and tetrahydroharmine, are comprehensively covered, particularly emphasizing the psychological, physiological, and toxic effects deriving from their concomitant intake. Potential therapeutic utility, particularly in mental and psychiatric disorders, and forensic aspects of DMT and ayahuasca are also reviewed and discussed. Following administration of ayahuasca, DMT is rapidly absorbed and distributed. Harmala alkaloids act as potent inhibitors of monoamine oxidase A (MAO-A), preventing extensive first-pass degradation of DMT into 3-indole-acetic acid (3-IAA), and enabling sufficient amounts of DMT to reach the brain. DMT has affinity for a variety of serotonergic and non-serotonergic receptors, though its psychotropic effects are mainly related with the activation of serotonin receptors type 2A (5-HT2A). Mildly to rarely severe psychedelic adverse effects are reported for ayahuasca or its alkaloids individually, but abuse does not lead to dependence or tolerance. For a long time, the evidence has pointed to potential psychotherapeutic benefits in the treatment of depression, anxiety, and substance abuse disorders; and although misuse of ayahuasca has been diverting attention away from such clinical potential, research onto its therapeutic effects has now strongly resurged.
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Affiliation(s)
- Andreia Machado Brito-da-Costa
- Department of Sciences, IINFACTS-Institute of Research and Advanced Training in Health Sciences and Technologies, University Institute of Health Sciences (IUCS), CESPU, CRL, 4585-116 Gandra, Portugal; (A.M.B.-d.-C.); (N.G.M.G.); (Á.M.-C.)
| | - Diana Dias-da-Silva
- Department of Sciences, IINFACTS-Institute of Research and Advanced Training in Health Sciences and Technologies, University Institute of Health Sciences (IUCS), CESPU, CRL, 4585-116 Gandra, Portugal; (A.M.B.-d.-C.); (N.G.M.G.); (Á.M.-C.)
- UCIBIO-REQUIMTE, Laboratory of Toxicology, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal
- Correspondence: (D.D.-d.-S.); (R.J.D.-O.); Tel.: +351-224-157-216 (R.J.D.-O.)
| | - Nelson G. M. Gomes
- Department of Sciences, IINFACTS-Institute of Research and Advanced Training in Health Sciences and Technologies, University Institute of Health Sciences (IUCS), CESPU, CRL, 4585-116 Gandra, Portugal; (A.M.B.-d.-C.); (N.G.M.G.); (Á.M.-C.)
- LAQV-REQUIMTE, Laboratory of Pharmacognosy, Department of Chemistry, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal
| | - Ricardo Jorge Dinis-Oliveira
- Department of Sciences, IINFACTS-Institute of Research and Advanced Training in Health Sciences and Technologies, University Institute of Health Sciences (IUCS), CESPU, CRL, 4585-116 Gandra, Portugal; (A.M.B.-d.-C.); (N.G.M.G.); (Á.M.-C.)
- UCIBIO-REQUIMTE, Laboratory of Toxicology, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal
- Department of Public Health and Forensic Sciences, and Medical Education, Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal
- Correspondence: (D.D.-d.-S.); (R.J.D.-O.); Tel.: +351-224-157-216 (R.J.D.-O.)
| | - Áurea Madureira-Carvalho
- Department of Sciences, IINFACTS-Institute of Research and Advanced Training in Health Sciences and Technologies, University Institute of Health Sciences (IUCS), CESPU, CRL, 4585-116 Gandra, Portugal; (A.M.B.-d.-C.); (N.G.M.G.); (Á.M.-C.)
- LAQV-REQUIMTE, Laboratory of Pharmacognosy, Department of Chemistry, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal
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11
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Alamia A, Timmermann C, Nutt DJ, VanRullen R, Carhart-Harris RL. DMT alters cortical travelling waves. eLife 2020; 9:e59784. [PMID: 33043883 PMCID: PMC7577737 DOI: 10.7554/elife.59784] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 10/11/2020] [Indexed: 12/25/2022] Open
Abstract
Psychedelic drugs are potent modulators of conscious states and therefore powerful tools for investigating their neurobiology. N,N, Dimethyltryptamine (DMT) can rapidly induce an extremely immersive state of consciousness characterized by vivid and elaborate visual imagery. Here, we investigated the electrophysiological correlates of the DMT-induced altered state from a pool of participants receiving DMT and (separately) placebo (saline) while instructed to keep their eyes closed. Consistent with our hypotheses, results revealed a spatio-temporal pattern of cortical activation (i.e. travelling waves) similar to that elicited by visual stimulation. Moreover, the typical top-down alpha-band rhythms of closed-eyes rest were significantly decreased, while the bottom-up forward wave was significantly increased. These results support a recent model proposing that psychedelics reduce the 'precision-weighting of priors', thus altering the balance of top-down versus bottom-up information passing. The robust hypothesis-confirming nature of these findings imply the discovery of an important mechanistic principle underpinning psychedelic-induced altered states.
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Affiliation(s)
| | - Christopher Timmermann
- Computational, Cognitive and Clinical Neuroscience Laboratory (C3NL), Faculty of Medicine, Imperial CollegeLondonUnited Kingdom
- Centre for Psychedelic Research, Division of Psychiatry, Department of Brain Sciences, Imperial College LondonLondonUnited Kingdom
| | - David J Nutt
- Centre for Psychedelic Research, Division of Psychiatry, Department of Brain Sciences, Imperial College LondonLondonUnited Kingdom
| | - Rufin VanRullen
- Cerco, CNRS Université de ToulouseToulouseFrance
- Artificial and Natural Intelligence Toulouse Institute (ANITI)ToulouseFrance
| | - Robin L Carhart-Harris
- Centre for Psychedelic Research, Division of Psychiatry, Department of Brain Sciences, Imperial College LondonLondonUnited Kingdom
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12
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Davis AK, Clifton JM, Weaver EG, Hurwitz ES, Johnson MW, Griffiths RR. Survey of entity encounter experiences occasioned by inhaled N,N-dimethyltryptamine: Phenomenology, interpretation, and enduring effects. J Psychopharmacol 2020; 34:1008-1020. [PMID: 32345112 DOI: 10.1177/0269881120916143] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
BACKGROUND Experiences of having an encounter with seemingly autonomous entities are sometimes reported after inhaling N,N-dimethyltryptamine. AIM The study characterized the subjective phenomena, interpretation, and persisting changes that people attribute to N,N-dimethyltryptamine-occasioned entity encounter experiences. METHODS Two thousand, five hundred and sixty-one individuals (mean age 32 years; 77% male) completed an online survey about their single most memorable entity encounter after taking N,N-dimethyltryptamine. RESULTS Respondents reported the primary senses involved in the encounter were visual and extrasensory (e.g. telepathic). The most common descriptive labels for the entity were being, guide, spirit, alien, and helper. Although 41% of respondents reported fear during the encounter, the most prominent emotions both in the respondent and attributed to the entity were love, kindness, and joy. Most respondents endorsed that the entity had the attributes of being conscious, intelligent, and benevolent, existed in some real but different dimension of reality, and continued to exist after the encounter. Respondents endorsed receiving a message (69%) or a prediction about the future (19%) from the experience. More than half of those who identified as atheist before the experience no longer identified as atheist afterwards. The experiences were rated as among the most meaningful, spiritual, and psychologically insightful lifetime experiences, with persisting positive changes in life satisfaction, purpose, and meaning attributed to the experiences. CONCLUSION N,N-dimethyltryptamine-occasioned entity encounter experiences have many similarities to non-drug entity encounter experiences such as those described in religious, alien abduction, and near-death contexts. Aspects of the experience and its interpretation produced profound and enduring ontological changes in worldview.
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Affiliation(s)
- Alan K Davis
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, USA.,College of Social Work, The Ohio State University, Columbus, USA
| | - John M Clifton
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, USA.,University of Maryland School of Medicine, Baltimore, USA
| | - Eric G Weaver
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, USA
| | - Ethan S Hurwitz
- Department of Psychology, University of California San Diego, La Jolla, USA
| | - Matthew W Johnson
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, USA
| | - Roland R Griffiths
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, USA.,Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, USA
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13
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Dean JG, Liu T, Huff S, Sheler B, Barker SA, Strassman RJ, Wang MM, Borjigin J. Biosynthesis and Extracellular Concentrations of N,N-dimethyltryptamine (DMT) in Mammalian Brain. Sci Rep 2019; 9:9333. [PMID: 31249368 PMCID: PMC6597727 DOI: 10.1038/s41598-019-45812-w] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 06/10/2019] [Indexed: 02/07/2023] Open
Abstract
N,N-dimethyltryptamine (DMT), a psychedelic compound identified endogenously in mammals, is biosynthesized by aromatic-L-amino acid decarboxylase (AADC) and indolethylamine-N-methyltransferase (INMT). Whether DMT is biosynthesized in the mammalian brain is unknown. We investigated brain expression of INMT transcript in rats and humans, co-expression of INMT and AADC mRNA in rat brain and periphery, and brain concentrations of DMT in rats. INMT transcripts were identified in the cerebral cortex, pineal gland, and choroid plexus of both rats and humans via in situ hybridization. Notably, INMT mRNA was colocalized with AADC transcript in rat brain tissues, in contrast to rat peripheral tissues where there existed little overlapping expression of INMT with AADC transcripts. Additionally, extracellular concentrations of DMT in the cerebral cortex of normal behaving rats, with or without the pineal gland, were similar to those of canonical monoamine neurotransmitters including serotonin. A significant increase of DMT levels in the rat visual cortex was observed following induction of experimental cardiac arrest, a finding independent of an intact pineal gland. These results show for the first time that the rat brain is capable of synthesizing and releasing DMT at concentrations comparable to known monoamine neurotransmitters and raise the possibility that this phenomenon may occur similarly in human brains.
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Affiliation(s)
- Jon G Dean
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA.,Center for Consciousness Science, University of Michigan, Ann Arbor, MI, USA
| | - Tiecheng Liu
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Sean Huff
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Ben Sheler
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - Steven A Barker
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA
| | - Rick J Strassman
- Department of Psychiatry, University of New Mexico School of Medicine, Albuquerque, NM, USA
| | - Michael M Wang
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA.,Department of Neurology, University of Michigan, Ann Arbor, MI, USA.,Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA.,VA Ann Arbor Healthcare System, Ann Arbor, MI, USA
| | - Jimo Borjigin
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA. .,Department of Neurology, University of Michigan, Ann Arbor, MI, USA. .,Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, USA. .,Center for Consciousness Science, University of Michigan, Ann Arbor, MI, USA.
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14
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Rodrigues AVSL, Almeida FJ, Vieira-Coelho MA. Dimethyltryptamine: Endogenous Role and Therapeutic Potential. J Psychoactive Drugs 2019; 51:299-310. [DOI: 10.1080/02791072.2019.1602291] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Alexandra VSL Rodrigues
- Department of Biomedicine-Pharmacology and Therapeutics unit, Faculty of Medicine, University of Porto, Porto, Portugal
| | - Francisco Jcg Almeida
- Department of Biomedicine-Pharmacology and Therapeutics unit, Faculty of Medicine, University of Porto, Porto, Portugal
| | - Maria A Vieira-Coelho
- Department of Biomedicine-Pharmacology and Therapeutics unit, Faculty of Medicine, University of Porto, Porto, Portugal
- Psychiatry and Mental Health Clinic, Hospital de São João, Porto, Portugal
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15
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Cameron LP, Olson DE. Dark Classics in Chemical Neuroscience: N, N-Dimethyltryptamine (DMT). ACS Chem Neurosci 2018; 9:2344-2357. [PMID: 30036036 DOI: 10.1021/acschemneuro.8b00101] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Though relatively obscure, N, N-dimethyltryptamine (DMT) is an important molecule in psychopharmacology as it is the archetype for all indole-containing serotonergic psychedelics. Its structure can be found embedded within those of better-known molecules such as lysergic acid diethylamide (LSD) and psilocybin. Unlike the latter two compounds, DMT is ubiquitous, being produced by a wide variety of plant and animal species. It is one of the principal psychoactive components of ayahuasca, a tisane made from various plant sources that has been used for centuries. Furthermore, DMT is one of the few psychedelic compounds produced endogenously by mammals, and its biological function in human physiology remains a mystery. In this review, we cover the synthesis of DMT as well as its pharmacology, metabolism, adverse effects, and potential use in medicine. Finally, we discuss the history of DMT in chemical neuroscience and why this underappreciated molecule is so important to the field of psychedelic science.
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Affiliation(s)
- Lindsay P. Cameron
- Neuroscience Graduate Program, University of California, Davis, 1544 Newton Ct., Davis, California 95618, United States
| | - David E. Olson
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, California 95616, United States
- Department of Biochemistry & Molecular Medicine, School of Medicine, University of California, Davis, 2700 Stockton Blvd., Suite 2102, Sacramento, California 95817, United States
- Center for Neuroscience, University of California, Davis, 1544 Newton Ct., Davis, California 95618, United States
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16
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Barker SA. N, N-Dimethyltryptamine (DMT), an Endogenous Hallucinogen: Past, Present, and Future Research to Determine Its Role and Function. Front Neurosci 2018; 12:536. [PMID: 30127713 PMCID: PMC6088236 DOI: 10.3389/fnins.2018.00536] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 07/17/2018] [Indexed: 01/12/2023] Open
Abstract
This report provides a historical overview of research concerning the endogenous hallucinogen N, N-dimethyltryptamine (DMT), focusing on data regarding its biosynthesis and metabolism in the brain and peripheral tissues, methods and results for DMT detection in body fluids and brain, new sites of action for DMT, and new data regarding its possible physiological and therapeutic roles. Research that further elaborates its consideration as a putative neurotransmitter is also addressed. Taking these studies together, the report proposes several new directions and experiments to ascertain the role of DMT in the brain, including brain mapping of enzymes responsible for the biosynthesis of DMT, further studies to elaborate its presence and role in the pineal gland, a reconsideration of binding site data, and new administration and imaging studies. The need to resolve the "natural" role of an endogenous hallucinogen from the effects observed from peripheral administration are also emphasized.
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Affiliation(s)
- Steven A. Barker
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, United States
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17
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Dean JG. Indolethylamine- N-methyltransferase Polymorphisms: Genetic and Biochemical Approaches for Study of Endogenous N,N,-dimethyltryptamine. Front Neurosci 2018; 12:232. [PMID: 29740267 PMCID: PMC5924808 DOI: 10.3389/fnins.2018.00232] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 03/23/2018] [Indexed: 12/05/2022] Open
Abstract
N,N-dimethyltryptamine (DMT) is a powerful serotonergic psychedelic whose exogenous administration elicits striking psychedelic effects in humans. Studies have identified DMT and analogous compounds (e.g., 5-hydroxy-DMT, 5-methoxy-DMT) alongside of an enzyme capable of synthesizing DMT endogenously from tryptamine, indolethylamine-N-methyltransferase (INMT), in human and several other mammalian tissues. Subsequently, multiple hypotheses for the physiological role of endogenous DMT have emerged, from proposed immunomodulatory functions to an emphasis on the overlap between the mental states generated by exogenous DMT and naturally occurring altered states of consciousness; e.g., schizophrenia. However, no clear relationship between endogenous DMT and naturally occurring altered states of consciousness has yet been established from in vivo assays of DMT in bodily fluids. The advent of genetic screening has afforded the capability to link alterations in the sequence of specific genes to behavioral and molecular phenotypes via expression of identified single nucleotide polymorphisms (SNPs) in cell and animal models. As SNPs in INMT may impact endogenous DMT synthesis and levels via changes in INMT expression and/or INMT structure and function, these combined genetic and biochemical approaches circumvent the limitations of assaying DMT in bodily fluids and may augment data from prior in vitro and in vivo work. Therefore, all reported SNPs in INMT were amassed from genetic and biochemical literature and genomic databases to consolidate a blueprint for future studies aimed at elucidating whether DMT plays a physiological role.
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Affiliation(s)
- Jon G Dean
- Molecular and Integrative Physiology, Center for Consciousness Science, University of Michigan, Ann Arbor, MI, United States
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18
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Penke B, Fülöp L, Szűcs M, Frecska E. The Role of Sigma-1 Receptor, an Intracellular Chaperone in Neurodegenerative Diseases. Curr Neuropharmacol 2018; 16:97-116. [PMID: 28554311 PMCID: PMC5771390 DOI: 10.2174/1570159x15666170529104323] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 04/15/2017] [Accepted: 05/25/2017] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Widespread protein aggregation occurs in the living system under stress or during aging, owing to disturbance of endoplasmic reticulum (ER) proteostasis. Many neurodegenerative diseases may have a common mechanism: the failure of protein homeostasis. Perturbation of ER results in unfolded protein response (UPR). Prolonged chronical UPR may activate apoptotic pathways and cause cell death. METHODS Research articles on Sigma-1 receptor were reviewed. RESULTS ER is associated to mitochondria by the mitochondria-associated ER-membrane, MAM. The sigma-1 receptor (Sig-1R), a well-known ER-chaperone localizes in the MAM. It serves for Ca2+-signaling between the ER and mitochondria, involved in ion channel activities and especially important during neuronal differentiation. Sig-1R acts as central modulator in inter-organelle signaling. Sig-1R helps cell survival by attenuating ER-stress. According to sequence based predictions Sig-1R is a 223 amino acid protein with two transmembrane (2TM) domains. The X-ray structure of the Sig-1R [1] showed a membrane-bound trimeric assembly with one transmembrane (1TM) region. Despite the in vitro determined assembly, the results of in vivo studies are rather consistent with the 2TM structure. The receptor has unique and versatile pharmacological profile. Dimethyl tryptamine (DMT) and neuroactive steroids are endogenous ligands that activate Sig-1R. The receptor has a plethora of interacting client proteins. Sig-1R exists in oligomeric structures (dimer-trimer-octamer-multimer) and this fact may explain interaction with diverse proteins. CONCLUSION Sig-1R agonists have been used in the treatment of different neurodegenerative diseases, e.g. Alzheimer's and Parkinson's diseases (AD and PD) and amyotrophic lateral sclerosis. Utilization of Sig-1R agents early in AD and similar other diseases has remained an overlooked therapeutic opportunity.
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Affiliation(s)
- Botond Penke
- University of Szeged, Department of Medical Chemistry, Faculty of Medicine, Szeged, Hungary
| | - Lívia Fülöp
- University of Szeged, Department of Medical Chemistry, Faculty of Medicine, Szeged, Hungary
| | - Mária Szűcs
- University of Szeged, Department of Medical Chemistry, Faculty of Medicine, Szeged, Hungary
| | - Ede Frecska
- University of Debrecen, Department of Psychiatry, Faculty of Medicine, Debrecen, Hungary
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19
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Hassan Z, Bosch OG, Singh D, Narayanan S, Kasinather BV, Seifritz E, Kornhuber J, Quednow BB, Müller CP. Novel Psychoactive Substances-Recent Progress on Neuropharmacological Mechanisms of Action for Selected Drugs. Front Psychiatry 2017; 8:152. [PMID: 28868040 PMCID: PMC5563308 DOI: 10.3389/fpsyt.2017.00152] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 08/02/2017] [Indexed: 12/15/2022] Open
Abstract
A feature of human culture is that we can learn to consume chemical compounds, derived from natural plants or synthetic fabrication, for their psychoactive effects. These drugs change the mental state and/or the behavioral performance of an individual and can be instrumentalized for various purposes. After the emergence of a novel psychoactive substance (NPS) and a period of experimental consumption, personal and medical benefits and harm potential of the NPS can be estimated on evidence base. This may lead to a legal classification of the NPS, which may range from limited medical use, controlled availability up to a complete ban of the drug form publically accepted use. With these measures, however, a drug does not disappear, but frequently continues to be used, which eventually allows an even better estimate of the drug's properties. Thus, only in rare cases, there is a final verdict that is no more questioned. Instead, the view on a drug can change from tolerable to harmful but may also involve the new establishment of a desired medical application to a previously harmful drug. Here, we provide a summary review on a number of NPS for which the neuropharmacological evaluation has made important progress in recent years. They include mitragynine ("Kratom"), synthetic cannabinoids (e.g., "Spice"), dimethyltryptamine and novel serotonergic hallucinogens, the cathinones mephedrone and methylone, ketamine and novel dissociative drugs, γ-hydroxybutyrate, γ-butyrolactone, and 1,4-butanediol. This review shows not only emerging harm potentials but also some potential medical applications.
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Affiliation(s)
- Zurina Hassan
- Centre for Drug Research, Universiti Sains Malaysia, Minden, Malaysia
| | - Oliver G Bosch
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland
| | - Darshan Singh
- Centre for Drug Research, Universiti Sains Malaysia, Minden, Malaysia
| | - Suresh Narayanan
- School of Social Sciences, Universiti Sains Malaysia, Minden, Malaysia
| | | | - Erich Seifritz
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland
| | - Johannes Kornhuber
- Department of Psychiatry and Psychotherapy, University Hospital, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
| | - Boris B Quednow
- Experimental and Clinical Pharmacopsychology, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland
| | - Christian P Müller
- Department of Psychiatry and Psychotherapy, University Hospital, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany
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20
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Carbonaro TM, Gatch MB. Neuropharmacology of N,N-dimethyltryptamine. Brain Res Bull 2016; 126:74-88. [PMID: 27126737 PMCID: PMC5048497 DOI: 10.1016/j.brainresbull.2016.04.016] [Citation(s) in RCA: 110] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 04/21/2016] [Accepted: 04/22/2016] [Indexed: 12/20/2022]
Abstract
N,N-dimethyltryptamine (DMT) is an indole alkaloid widely found in plants and animals. It is best known for producing brief and intense psychedelic effects when ingested. Increasing evidence suggests that endogenous DMT plays important roles for a number of processes in the periphery and central nervous system, and may act as a neurotransmitter. This paper reviews the current literature of both the recreational use of DMT and its potential roles as an endogenous neurotransmitter. Pharmacokinetics, mechanisms of action in the periphery and central nervous system, clinical uses and adverse effects are also reviewed. DMT appears to have limited neurotoxicity and other adverse effects except for intense cardiovascular effects when administered intravenously in large doses. Because of its role in nervous system signaling, DMT may be a useful experimental tool in exploring how the brain works, and may also be a useful clinical tool for treatment of anxiety and psychosis.
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Affiliation(s)
- Theresa M Carbonaro
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Michael B Gatch
- Center for Neuroscience Discovery University of North Texas Health Science Center Fort Worth, TX, United States.
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21
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Frecska E, Bokor P, Winkelman M. The Therapeutic Potentials of Ayahuasca: Possible Effects against Various Diseases of Civilization. Front Pharmacol 2016; 7:35. [PMID: 26973523 PMCID: PMC4773875 DOI: 10.3389/fphar.2016.00035] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 02/08/2016] [Indexed: 11/23/2022] Open
Abstract
Ayahuasca is an Amazonian psychoactive brew of two main components. Its active agents are β-carboline and tryptamine derivatives. As a sacrament, ayahuasca is still a central element of many healing ceremonies in the Amazon Basin and its ritual consumption has become common among the mestizo populations of South America. Ayahuasca use amongst the indigenous people of the Amazon is a form of traditional medicine and cultural psychiatry. During the last two decades, the substance has become increasingly known among both scientists and laymen, and currently its use is spreading all over in the Western world. In the present paper we describe the chief characteristics of ayahuasca, discuss important questions raised about its use, and provide an overview of the scientific research supporting its potential therapeutic benefits. A growing number of studies indicate that the psychotherapeutic potential of ayahuasca is based mostly on the strong serotonergic effects, whereas the sigma-1 receptor (Sig-1R) agonist effect of its active ingredient dimethyltryptamine raises the possibility that the ethnomedical observations on the diversity of treated conditions can be scientifically verified. Moreover, in the right therapeutic or ritual setting with proper preparation and mindset of the user, followed by subsequent integration of the experience, ayahuasca has proven effective in the treatment of substance dependence. This article has two important take-home messages: (1) the therapeutic effects of ayahuasca are best understood from a bio-psycho-socio-spiritual model, and (2) on the biological level ayahuasca may act against chronic low grade inflammation and oxidative stress via the Sig-1R which can explain its widespread therapeutic indications.
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Affiliation(s)
- Ede Frecska
- Department of Psychiatry, Faculty of Medicine, University of Debrecen Debrecen, Hungary
| | - Petra Bokor
- Doctoral School of Psychology, University of Pécs Pécs, Hungary
| | - Michael Winkelman
- School of Human Evolution and Social Change, Arizona State University, Tempe AZ, USA
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22
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Szabo A. Psychedelics and Immunomodulation: Novel Approaches and Therapeutic Opportunities. Front Immunol 2015; 6:358. [PMID: 26236313 PMCID: PMC4500993 DOI: 10.3389/fimmu.2015.00358] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 06/30/2015] [Indexed: 12/12/2022] Open
Abstract
Classical psychedelics are psychoactive substances, which, besides their psychopharmacological activity, have also been shown to exert significant modulatory effects on immune responses by altering signaling pathways involved in inflammation, cellular proliferation, and cell survival via activating NF-κB and mitogen-activated protein kinases. Recently, several neurotransmitter receptors involved in the pharmacology of psychedelics, such as serotonin and sigma-1 receptors, have also been shown to play crucial roles in numerous immunological processes. This emerging field also offers promising treatment modalities in the therapy of various diseases including autoimmune and chronic inflammatory conditions, infections, and cancer. However, the scarcity of available review literature renders the topic unclear and obscure, mostly posing psychedelics as illicit drugs of abuse and not as physiologically relevant molecules or as possible agents of future pharmacotherapies. In this paper, the immunomodulatory potential of classical serotonergic psychedelics, including N,N-dimethyltryptamine (DMT), 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT), lysergic acid diethylamide (LSD), 2,5-dimethoxy-4-iodoamphetamine, and 3,4-methylenedioxy-methamphetamine will be discussed from a perspective of molecular immunology and pharmacology. Special attention will be given to the functional interaction of serotonin and sigma-1 receptors and their cross-talk with toll-like and RIG-I-like pattern-recognition receptor-mediated signaling. Furthermore, novel approaches will be suggested feasible for the treatment of diseases with chronic inflammatory etiology and pathology, such as atherosclerosis, rheumatoid arthritis, multiple sclerosis, schizophrenia, depression, and Alzheimer’s disease.
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Affiliation(s)
- Attila Szabo
- Department of Immunology, Faculty of Medicine, University of Debrecen , Debrecen , Hungary
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Araújo AM, Carvalho F, Bastos MDL, Guedes de Pinho P, Carvalho M. The hallucinogenic world of tryptamines: an updated review. Arch Toxicol 2015; 89:1151-73. [PMID: 25877327 DOI: 10.1007/s00204-015-1513-x] [Citation(s) in RCA: 118] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 03/25/2015] [Indexed: 12/25/2022]
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Szabo A, Kovacs A, Frecska E, Rajnavolgyi E. Psychedelic N,N-dimethyltryptamine and 5-methoxy-N,N-dimethyltryptamine modulate innate and adaptive inflammatory responses through the sigma-1 receptor of human monocyte-derived dendritic cells. PLoS One 2014; 9:e106533. [PMID: 25171370 PMCID: PMC4149582 DOI: 10.1371/journal.pone.0106533] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 08/08/2014] [Indexed: 12/24/2022] Open
Abstract
The orphan receptor sigma-1 (sigmar-1) is a transmembrane chaperone protein expressed in both the central nervous system and in immune cells. It has been shown to regulate neuronal differentiation and cell survival, and mediates anti-inflammatory responses and immunosuppression in murine in vivo models. Since the details of these findings have not been elucidated so far, we studied the effects of the endogenous sigmar-1 ligands N,N-dimethyltryptamine (NN-DMT), its derivative 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) and the synthetic high affinity sigmar-1 agonist PRE-084 hydrochloride on human primary monocyte-derived dendritic cell (moDCs) activation provoked by LPS, polyI:C or pathogen-derived stimuli to induce inflammatory responses. Co-treatment of moDC with these activators and sigma-1 receptor ligands inhibited the production of pro-inflammatory cytokines IL-1β, IL-6, TNFα and the chemokine IL-8, while increased the secretion of the anti-inflammatory cytokine IL-10. The T-cell activating capacity of moDCs was also inhibited, and dimethyltryptamines used in combination with E. coli or influenza virus as stimulators decreased the differentiation of moDC-induced Th1 and Th17 inflammatory effector T-cells in a sigmar-1 specific manner as confirmed by gene silencing. Here we demonstrate for the first time the immunomodulatory potential of NN-DMT and 5-MeO-DMT on human moDC functions via sigmar-1 that could be harnessed for the pharmacological treatment of autoimmune diseases and chronic inflammatory conditions of the CNS or peripheral tissues. Our findings also point out a new biological role for dimethyltryptamines, which may act as systemic endogenous regulators of inflammation and immune homeostasis through the sigma-1 receptor.
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Affiliation(s)
- Attila Szabo
- Department of Immunology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
- Research Centre for Molecular Medicine, University of Debrecen, Debrecen, Hungary
| | - Attila Kovacs
- Department of Psychiatry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Ede Frecska
- Department of Psychiatry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Eva Rajnavolgyi
- Department of Immunology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
- Research Centre for Molecular Medicine, University of Debrecen, Debrecen, Hungary
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Winstock AR, Kaar S, Borschmann R. Dimethyltryptamine (DMT): prevalence, user characteristics and abuse liability in a large global sample. J Psychopharmacol 2014; 28:49-54. [PMID: 24284475 DOI: 10.1177/0269881113513852] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This paper presents original research on prevalence, user characteristics and effect profile of N,N-dimethyltryptamine (DMT), a potent hallucinogenic which acts primarily through the serotonergic system. Data were obtained from the Global Drug Survey (an anonymous online survey of people, many of whom have used drugs) conducted between November and December 2012 with 22,289 responses. Lifetime prevalence of DMT use was 8.9% (n=1980) and past year prevalence use was 5.0% (n=1123). We explored the effect profile of DMT in 472 participants who identified DMT as the last new drug they had tried for the first time and compared it with ratings provided by other respondents on psilocybin (magic mushrooms), LSD and ketamine. DMT was most often smoked and offered a strong, intense, short-lived psychedelic high with relatively few negative effects or "come down". It had a larger proportion of new users compared with the other substances (24%), suggesting its popularity may increase. Overall, DMT seems to have a very desirable effect profile indicating a high abuse liability that maybe offset by a low urge to use more.
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Affiliation(s)
- Adam R Winstock
- 1Addiction CAG, South London and Maudsley NHS Trust, Southwark CDAT, London, UK
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Frecska E, Szabo A, Winkelman MJ, Luna LE, McKenna DJ. A possibly sigma-1 receptor mediated role of dimethyltryptamine in tissue protection, regeneration, and immunity. J Neural Transm (Vienna) 2013; 120:1295-303. [PMID: 23619992 DOI: 10.1007/s00702-013-1024-y] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 04/01/2013] [Indexed: 01/20/2023]
Abstract
N,N-dimethyltryptamine (DMT) is classified as a naturally occurring serotonergic hallucinogen of plant origin. It has also been found in animal tissues and regarded as an endogenous trace amine transmitter. The vast majority of research on DMT has targeted its psychotropic/psychedelic properties with less focus on its effects beyond the nervous system. The recent discovery that DMT is an endogenous ligand of the sigma-1 receptor may shed light on yet undiscovered physiological mechanisms of DMT activity and reveal some of its putative biological functions. A three-step active uptake process of DMT from peripheral sources to neurons underscores a presumed physiological significance of this endogenous hallucinogen. In this paper, we overview the literature on the effects of sigma-1 receptor ligands on cellular bioenergetics, the role of serotonin, and serotoninergic analogues in immunoregulation and the data regarding gene expression of the DMT synthesizing enzyme indolethylamine-N-methyltransferase in carcinogenesis. We conclude that the function of DMT may extend central nervous activity and involve a more universal role in cellular protective mechanisms. Suggestions are offered for future directions of indole alkaloid research in the general medical field. We provide converging evidence that while DMT is a substance which produces powerful psychedelic experiences, it is better understood not as a hallucinogenic drug of abuse, but rather an agent of significant adaptive mechanisms that can also serve as a promising tool in the development of future medical therapies.
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Affiliation(s)
- Ede Frecska
- Department of Psychiatry, Medical and Health Science Center, University of Debrecen, Nagyerdei krt. 98, 4012, Debrecen, Hungary.
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28
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Morris PE, Chiao C. Indolealkylamine metabolism: Synthesis of deuterated indolealkylamines as metabolic probes. J Labelled Comp Radiopharm 2006. [DOI: 10.1002/jlcr.2580330603] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Jacob MS, Presti DE. Endogenous psychoactive tryptamines reconsidered: an anxiolytic role for dimethyltryptamine. Med Hypotheses 2005; 64:930-7. [PMID: 15780487 DOI: 10.1016/j.mehy.2004.11.005] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2004] [Accepted: 11/04/2004] [Indexed: 12/17/2022]
Abstract
The presence of the potent hallucinogenic psychoactive chemical N,N-dimethyltryptamine (DMT) in the human body has puzzled scientists for decades. Endogenous DMT was investigated in the 1960s and 1970s and it was proposed that DMT was involved in psychosis and schizophrenia. This hypothesis developed from comparisons of the blood and urine of schizophrenic and control subjects. However, much of this research proved inconclusive and conventional thinking has since held that trace levels of DMT, and other endogenous psychoactive tryptamines, are insignificant metabolic byproducts. The recent discovery of a G-protein-coupled, human trace amine receptor has triggered a reappraisal of the role of compounds present in limited concentrations in biological systems. Interestingly enough, DMT and other psychoactive tryptamine hallucinogens elicit a robust response at the trace amine receptor. While it is currently accepted that serotonin 5-HT(2A) receptors play a pivotal role in the activity of hallucinogenic/psychedelic compounds, we propose that the effects induced by exogenous DMT administration, especially at low doses, are due in part to activity at the trace amine receptor. Furthermore, we suggest that endogenous DMT interacts with the TA receptor to produce a calm and relaxed mental state, which may suppress, rather than promote, symptoms of psychosis. This hypothesis may help explain the inconsistency in the early analysis of endogenous DMT in humans. Finally, we propose that amphetamine action at the TA receptor may contribute to the calming effects of amphetamine and related drugs, especially at low doses.
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Affiliation(s)
- Michael S Jacob
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3200, USA
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Barker SA, Littlefield-Chabaud MA, David C. Distribution of the hallucinogens N,N-dimethyltryptamine and 5-methoxy-N,N-dimethyltryptamine in rat brain following intraperitoneal injection: application of a new solid-phase extraction LC-APcI-MS-MS-isotope dilution method. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 2001; 751:37-47. [PMID: 11232854 DOI: 10.1016/s0378-4347(00)00442-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
A method for the solid-phase extraction (SPE) and liquid chromatographic-atmospheric pressure chemical ionization-mass spectrometric-mass spectrometric-isotope dilution (LC-APcI-MS-MS-ID) analysis of the indole hallucinogens N,N-dimethyltryptamine (DMT) and 5-methoxy DMT (or O-methyl bufotenin, OMB) from rat brain tissue is reported. Rats were administered DMT or OMB by the intraperitoneal route at a dose of 5 mg/kg and sacrificed 15 min post treatment. Brains were dissected into discrete areas and analyzed by the methods described as a demonstration of the procedure's applicability. The synthesis and use of two new deuterated internal standards for these purposes are also reported.
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Affiliation(s)
- S A Barker
- Department of Physiology, Pharmacology and Toxicology, School of Veterinary Medicine, Louisiana State University, Baton Rouge 70803, USA.
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McKenna DJ, Repke DB, Lo L, Peroutka SJ. Differential interactions of indolealkylamines with 5-hydroxytryptamine receptor subtypes. Neuropharmacology 1990; 29:193-8. [PMID: 2139186 DOI: 10.1016/0028-3908(90)90001-8] [Citation(s) in RCA: 126] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Affinities of drugs for 21 indolealkylamine derivatives, some with putative hallucinogenic activity, were determined at 5-HT1A, 5-HT2A and 5-HT2B recognition sites, using radioligand competition studies. Nearly all of the derivatives displayed greatest potency for the 5-HT2A receptor, labelled by [125I]R-(-)DOI in the cortex of the rat. Most derivatives displayed 2-10 times lower affinity at the HT2B receptor labelled by [3H]ketanserin in bovine cortex. Derivatives lacking ring substituents displayed lower affinities for all of the recognition sites, compared to derivatives substituted in the 4- or 5-position of the indole ring. The 4-hydroxylated derivatives displayed 25-380-fold selectivity for the 5-HT2A site, vs the 5-HT1A site, while the 5-substituted derivatives displayed approximately equal potency at the 5-HT1A and 5-HT2A sites. Affinity of all the compounds at the 5-HT2B site was greater than 300 nM. The 6-substituted derivatives displayed greater than micromolar affinities for all of the 5-HT recognition sites examined. The size of the N,N-dialkyl substituent was a secondary determinant of affinity, with groups larger than N,N-diisopropyl resulting in a marked reduction in affinity at both the 5-HT2A and 5-HT1A recognition sites. This study demonstrated that hallucinogenic 4-hydroxy-indolealkylamines, like psychotomimetic phenylisopropylamines, bind potently and selectively to the 5-HT2A recognition site, labelled by [125I]R-(-)DOI. This provides further evidence indicating that this recently described subtype of the 5-HT2 receptor may partially mediate the action of hallucinogenic agents.
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Affiliation(s)
- D J McKenna
- Department of Neurology, Stanford University School of Medicine, California 94305
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Sitaram BR, Talomsin R, Blackman GL, McLeod WR. Study of metabolism of psychotomimetic indolealkylamines by rat tissue extracts using liquid chromatography. Biochem Pharmacol 1987; 36:1503-8. [PMID: 3472525 DOI: 10.1016/0006-2952(87)90117-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The use of a series of liquid chromatographic techniques involving cation-exchange, reverse-phase and normal-phase chromatography has permitted the separation and characterisation of a number of metabolites of the psychotomimetic indolealkylamines N,N-dimethyltryptamine and 5-methoxy-N,N-dimethyltryptamine which were isolated following incubation of these compounds with rat tissue extracts. In liver, kidney and brain tissue extracts the routes of metabolism identified included oxidative deamination, N-demethylation, O-demethylation and N-oxidation. The quantitative significance of individual routes of metabolism in these tissues was assessed using N,N-dimethyltryptamine as a substrate.
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Barker SA, Beaton JM, Christian ST, Monti JA, Morris PE. In vivo metabolism of alpha,alpha,beta,beta-tetradeutero-N, N-dimethyltryptamine in rodent brain. Biochem Pharmacol 1984; 33:1395-400. [PMID: 6587850 DOI: 10.1016/0006-2952(84)90404-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The metabolism of alpha,alpha,beta,beta- tetradeutero -N,N -dimethyltryptamine ( D4DMT ) in rat brain in vivo as a function of time and dose was examined. Quantification of D4DMT and its respective deutero-metabolites was accomplished using gas chromatographic/mass spectrometric/selected ion monitoring/isotope dilution techniques. The results of this study indicate that D4DMT is metabolized to the corresponding deutero-N-methyltryptamine, tryptamine, 1,2,3,4-tetrahydro-beta-carboline, and 2-methyl-1, 2,3,4-tetrahydro-beta-carboline in rat brain. The subcellular distribution of D4DMT and the aforementioned metabolites is also reported.
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Beaton JM, Barker SA, Liu WF. A comparison of the behavioral effects of proteo-and deutero-N, N-dimethyltryptamine. Pharmacol Biochem Behav 1982; 16:811-4. [PMID: 6806829 DOI: 10.1016/0091-3057(82)90240-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Barker SA, Harrison RE, Monti JA, Brown GB, Christian ST. Identification and quantification of 1,2,3,4-tetrahydro-beta-carboline, 2-methyl-1,2,3,4-tetrahydro-beta-carboline, and 6-methoxy-1,2,3,4-tetrahydro-beta-carboline as in vivo constituents of rat brain and adrenal gland. Biochem Pharmacol 1981; 30:9-17. [PMID: 7213417 DOI: 10.1016/0006-2952(81)90278-1] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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36
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Barker SA, Monti JA, Christian ST. N, N-dimethyltryptamine: an endogenous hallucinogen. INTERNATIONAL REVIEW OF NEUROBIOLOGY 1981; 22:83-110. [PMID: 6792104 DOI: 10.1016/s0074-7742(08)60291-3] [Citation(s) in RCA: 73] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Barker SA, Monti JA, Christian ST. Metabolism of the hallucinogen N,N-dimethyltryptamine in rat brain homogenates. Biochem Pharmacol 1980; 29:1049-57. [PMID: 6770869 DOI: 10.1016/0006-2952(80)90169-0] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Quayle ES, Pagel J, Monti JA, Christian ST. A serotonin sensitive guanylate cyclase associated with specific neurotransmitter binding sites on isolated synaptic membranes from mature rat brain. Life Sci 1978; 23:159-65. [PMID: 28459 DOI: 10.1016/0024-3205(78)90265-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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