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Abstract
BACKGROUND 5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) is a naturally occurring, short-acting psychedelic tryptamine, produced by a variety of plant and animal species. Plants containing 5-MeO-DMT have been used throughout history for ritual and spiritual purposes. The aim of this article is to review the available literature about 5-MeO-DMT and inform subsequent clinical development. METHODS We searched PubMed database for articles about 5-MeO-DMT. Search results were cross-checked against earlier reviews and reference lists were hand searched. Findings were synthesised using a narrative synthesis approach. This review covers the pharmacology, chemistry and metabolism of 5-MeO-DMT, as well epidemiological studies, and reported adverse and beneficial effects. RESULTS 5-MeO-DMT is serotonergic agonist, with highest affinity for 5-HT1A receptors. It was studied in a variety of animal models, but clinical studies with humans are lacking. Epidemiological studies indicate that, like other psychedelics, 5-MeO-DMT induces profound alterations in consciousness (including mystical experiences), with potential beneficial long-term effects on mental health and well-being. CONCLUSION 5-MeO-DMT is a potentially useful addition to the psychedelic pharmacopoeia because of its short duration of action, relative lack of visual effects and putatively higher rates of ego-dissolution and mystical experiences. We conclude that further clinical exploration is warranted, using similar precautions as with other classic psychedelics.
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Affiliation(s)
- Anna O Ermakova
- Beckley Psytech, Beckley, UK,Psychedelic Trials Group, Centre for Affective Disorders, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, UK,Anna O Ermakova, Psychedelic Trials Group, Centre for Affective Disorders, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, 16 De Crespigny Park, London SE5 8AF, UK.
| | | | - James Rucker
- Psychedelic Trials Group, Centre for Affective Disorders, Institute of Psychiatry, Psychology and Neuroscience, King’s College London, London, UK
| | - Matthew W Johnson
- Department of Psychiatry and Behavioral Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
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Bissig KD, Han W, Barzi M, Kovalchuk N, Ding L, Fan X, Pankowicz FP, Zhang QY, Ding X. P450-Humanized and Human Liver Chimeric Mouse Models for Studying Xenobiotic Metabolism and Toxicity. Drug Metab Dispos 2018; 46:1734-1744. [PMID: 30093418 DOI: 10.1124/dmd.118.083303] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 08/03/2018] [Indexed: 01/01/2023] Open
Abstract
Preclinical evaluation of drug candidates in experimental animal models is an essential step in drug development. Humanized mouse models have emerged as a promising alternative to traditional animal models. The purpose of this mini-review is to provide a brief survey of currently available mouse models for studying human xenobiotic metabolism. Here, we describe both genetic humanization and human liver chimeric mouse models, focusing on the advantages and limitations while outlining their key features and applications. Although this field of biomedical science is relatively young, these humanized mouse models have the potential to transform preclinical drug testing and eventually lead to a more cost-effective and rapid development of new therapies.
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Affiliation(s)
- Karl-Dimiter Bissig
- Baylor College of Medicine, Houston, Texas (K.-D.B., M.B., F.P.P.); and Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona (W.H., N.K., L.D., X.F., Q.-Y.Z., X.D.)
| | - Weiguo Han
- Baylor College of Medicine, Houston, Texas (K.-D.B., M.B., F.P.P.); and Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona (W.H., N.K., L.D., X.F., Q.-Y.Z., X.D.)
| | - Mercedes Barzi
- Baylor College of Medicine, Houston, Texas (K.-D.B., M.B., F.P.P.); and Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona (W.H., N.K., L.D., X.F., Q.-Y.Z., X.D.)
| | - Nataliia Kovalchuk
- Baylor College of Medicine, Houston, Texas (K.-D.B., M.B., F.P.P.); and Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona (W.H., N.K., L.D., X.F., Q.-Y.Z., X.D.)
| | - Liang Ding
- Baylor College of Medicine, Houston, Texas (K.-D.B., M.B., F.P.P.); and Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona (W.H., N.K., L.D., X.F., Q.-Y.Z., X.D.)
| | - Xiaoyu Fan
- Baylor College of Medicine, Houston, Texas (K.-D.B., M.B., F.P.P.); and Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona (W.H., N.K., L.D., X.F., Q.-Y.Z., X.D.)
| | - Francis P Pankowicz
- Baylor College of Medicine, Houston, Texas (K.-D.B., M.B., F.P.P.); and Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona (W.H., N.K., L.D., X.F., Q.-Y.Z., X.D.)
| | - Qing-Yu Zhang
- Baylor College of Medicine, Houston, Texas (K.-D.B., M.B., F.P.P.); and Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona (W.H., N.K., L.D., X.F., Q.-Y.Z., X.D.)
| | - Xinxin Ding
- Baylor College of Medicine, Houston, Texas (K.-D.B., M.B., F.P.P.); and Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona, Tucson, Arizona (W.H., N.K., L.D., X.F., Q.-Y.Z., X.D.)
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Development of a mechanism-based pharmacokinetic/pharmacodynamic model to characterize the thermoregulatory effects of serotonergic drugs in mice. Acta Pharm Sin B 2016; 6:492-503. [PMID: 27709018 PMCID: PMC5045556 DOI: 10.1016/j.apsb.2016.07.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Revised: 04/25/2016] [Accepted: 04/27/2016] [Indexed: 01/01/2023] Open
Abstract
We have shown recently that concurrent harmaline, a monoamine oxidase-A inhibitor (MAOI), potentiates serotonin (5-HT) receptor agonist 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT)-induced hyperthermia. The objective of this study was to develop an integrated pharmacokinetic/pharmacodynamic (PK/PD) model to characterize and predict the thermoregulatory effects of such serotonergic drugs in mice. Physiological thermoregulation was described by a mechanism-based indirect-response model with adaptive feedback control. Harmaline-induced hypothermia and 5-MeO-DMT–elicited hyperthermia were attributable to the loss of heat through the activation of 5-HT1A receptor and thermogenesis via the stimulation of 5-HT2A receptor, respectively. Thus serotonergic 5-MeO-DMT–induced hyperthermia was readily distinguished from handling/injection stress-provoked hyperthermic effects. This PK/PD model was able to simultaneously describe all experimental data including the impact of drug-metabolizing enzyme status on 5-MeO-DMT and harmaline PK properties, and drug- and stress-induced simple hypo/hyperthermic and complex biphasic effects. Furthermore, the modeling results revealed a 4-fold decrease of apparent SC50 value (1.88–0.496 µmol/L) for 5-MeO-DMT when harmaline was co-administered, providing a quantitative assessment for the impact of concurrent MAOI harmaline on 5-MeO-DMT–induced hyperthermia. In addition, the hyperpyrexia caused by toxic dose combinations of harmaline and 5-MeO-DMT were linked to the increased systemic exposure to harmaline rather than 5-MeO-DMT, although the body temperature profiles were mispredicted by the model. The results indicate that current PK/PD model may be used as a new conceptual framework to define the impact of serotonergic agents and stress factors on thermoregulation.
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Jiang XL, Shen HW, Yu AM. Modification of 5-methoxy-N,N-dimethyltryptamine-induced hyperactivity by monoamine oxidase A inhibitor harmaline in mice and the underlying serotonergic mechanisms. Pharmacol Rep 2016; 68:608-15. [PMID: 26977821 DOI: 10.1016/j.pharep.2016.01.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 12/17/2015] [Accepted: 01/21/2016] [Indexed: 01/03/2023]
Abstract
BACKGROUND 5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) and harmaline are indolealkylamine (IAA) drugs often abused together. Our recent studies have revealed the significant effects of co-administered harmaline, a monoamine oxidase inhibitor (MAOI), on 5-MeO-DMT pharmacokinetics and thermoregulation. This study was to delineate the impact of harmaline and 5-MeO-DMT on home-cage activity in mouse models, as well as the contribution of serotonin (5-HT) receptors. METHODS Home-cage activities of individual animals were monitored automatically in the home cages following implantation of telemetry transmitters and administration of various doses of IAA drugs and 5-HT receptor antagonists. Area under the effect curve (AUEC) of mouse activity values were calculated by trapezoidal rule. RESULTS High dose of harmaline (15mg/kg, ip) alone caused an early-phase (0-45min) hypoactivity in mice that was fully attenuated by 5-HT1A receptor antagonist WAY-100635, whereas a late-phase (45-180min) hyperactivity that was reduced by 5-HT2A receptor antagonist MDL-100907. 5-MeO-DMT (10 and 20mg/kg, ip) alone induced biphasic effects, an early-phase (0-45min) hypoactivity that was completely attenuated by WAY-100635, and a late-phase (45-180min) hyperactivity that was fully suppressed by MDL-100907. Interestingly, co-administration of MAOI harmaline (2-15mg/kg) with a subthreshold dose of 5-MeO-DMT (2mg/kg) induced excessive hyperactivities at late phase (45-180min) that could be abolished by either WAY-100635 or MDL-100907. CONCLUSIONS Co-administration of MAOI with 5-MeO-DMT provokes excessive late-phase hyperactivity, which involves the activation of both 5-HT1A and 5-HT2A receptors.
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Affiliation(s)
- Xi-Ling Jiang
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, The State University of New York, Buffalo, NY, USA
| | - Hong-Wu Shen
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, The State University of New York, Buffalo, NY, USA
| | - Ai-Ming Yu
- Department of Biochemistry & Molecular Medicine, UC Davis School of Medicine, Sacramento, CA, USA.
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Jiang XL, Shen HW, Yu AM. Potentiation of 5-methoxy-N,N-dimethyltryptamine-induced hyperthermia by harmaline and the involvement of activation of 5-HT1A and 5-HT2A receptors. Neuropharmacology 2015; 89:342-51. [PMID: 25446678 DOI: 10.1016/j.neuropharm.2014.10.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 10/08/2014] [Accepted: 10/13/2014] [Indexed: 10/24/2022]
Abstract
5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) and harmaline are serotonin (5-HT) analogs often abused together, which alters thermoregulation that may indicate the severity of serotonin toxicity. Our recent studies have revealed that co-administration of monoamine oxidase inhibitor harmaline leads to greater and prolonged exposure to 5-HT agonist 5-MeO-DMT that might be influenced by cytochrome P450 2D6 (CYP2D6) status. This study was to define the effects of harmaline and 5-MeO-DMT on thermoregulation in wild-type and CYP2D6-humanized (Tg-CYP2D6) mice, as well as the involvement of 5-HT receptors. Animal core body temperatures were monitored noninvasively in the home cages after implantation of telemetry transmitters and administration of drugs. Harmaline (5 and 15 mg/kg, i.p.) alone was shown to induce hypothermia that was significantly affected by CYP2D6 status. In contrast, higher doses of 5-MeO-DMT (10 and 20 mg/kg) alone caused hyperthermia. Co-administration of harmaline (2, 5 or 15 mg/kg) remarkably potentiated the hyperthermia elicited by 5-MeO-DMT (2 or 10 mg/kg), which might be influenced by CYP2D6 status at certain dose combination. Interestingly, harmaline-induced hypothermia was only attenuated by 5-HT1A receptor antagonist WAY-100635, whereas 5-MeO-DMT- and harmaline-5-MeO-DMT-induced hyperthermia could be suppressed by either WAY-100635 or 5-HT2A receptor antagonists (MDL-100907 and ketanserin). Moreover, stress-induced hyperthermia under home cage conditions was not affected by WAY-100635 but surprisingly attenuated by MDL-100907 and ketanserin. Our results indicate that co-administration of monoamine oxidase inhibitor largely potentiates 5-MeO-DMT-induced hyperthermia that involves the activation of both 5-HT1A and 5-HT2A receptors. These findings shall provide insights into development of anxiolytic drugs and new strategies to relieve the lethal hyperthermia in serotonin toxicity.
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Affiliation(s)
- Xi-Ling Jiang
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14214-8033, USA
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Cheng J, Zhen Y, Miksys S, Beyoğlu D, Krausz KW, Tyndale RF, Yu A, Idle JR, Gonzalez FJ. Potential role of CYP2D6 in the central nervous system. Xenobiotica 2013; 43:973-84. [PMID: 23614566 DOI: 10.3109/00498254.2013.791410] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
1. Cytochrome P450 2D6 (CYP2D6) is a pivotal enzyme responsible for a major drug oxidation polymorphism in human populations. Distribution of CYP2D6 in brain and its role in serotonin metabolism suggest that CYP2D6 may have a function in the central nervous system. 2. To establish an efficient and accurate platform for the study of CYP2D6 in vivo, a human CYP2D6 (Tg-2D6) model was generated by transgenesis in wild-type (WT) C57BL/6 mice using a P1 phage artificial chromosome clone containing the complete human CYP2D locus, including the CYP2D6 gene and 5'- and 3'-flanking sequences. 3. Human CYP2D6 was expressed not only in the liver but also in the brain. The abundance of serotonin and 5-hydroxyindoleacetic acid in brain of Tg-2D6 is higher than in WT mice, either basal levels or after harmaline induction. Metabolomics of brain homogenate and cerebrospinal fluid revealed a significant up-regulation of L-carnitine, acetyl-L-carnitine, pantothenic acid, 2'-deoxycytidine diphosphate (dCDP), anandamide, N-acetylglucosaminylamine and a down-regulation of stearoyl-L-carnitine in Tg-2D6 mice compared with WT mice. Anxiety tests indicate Tg-2D6 mice have a higher capability to adapt to anxiety. 4. Overall, these findings indicate that the Tg-2D6 mouse model may serve as a valuable in vivo tool to determine CYP2D6-involved neurophysiological metabolism and function.
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Affiliation(s)
- Jie Cheng
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health , Bethesda, MD , USA
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Genetic variability of drug-metabolizing enzymes: the dual impact on psychiatric therapy and regulation of brain function. Mol Psychiatry 2013; 18:273-87. [PMID: 22565785 DOI: 10.1038/mp.2012.42] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Polymorphic drug-metabolizing enzymes (DMEs) are responsible for the metabolism of the majority of psychotropic drugs. By explaining a large portion of variability in individual drug metabolism, pharmacogenetics offers a diagnostic tool in the burgeoning era of personalized medicine. This review updates existing evidence on the influence of pharmacogenetic variants on drug exposure and discusses the rationale for genetic testing in the clinical context. Dose adjustments based on pharmacogenetic knowledge are the first step to translate pharmacogenetics into clinical practice. However, also clinical factors, such as the consequences on toxicity and therapeutic failure, must be considered to provide clinical recommendations and assess the cost-effectiveness of pharmacogenetic treatment strategies. DME polymorphisms are relevant not only for clinical pharmacology and practice but also for research in psychiatry and neuroscience. Several DMEs, above all the cytochrome P (CYP) enzymes, are expressed in the brain, where they may contribute to the local biochemical homeostasis. Of particular interest is the possibility of DMEs playing a physiological role through their action on endogenous substrates, which may underlie the reported associations between genetic polymorphisms and cognitive function, personality and vulnerability to mental disorders. Neuroimaging studies have recently presented evidence of an effect of the CYP2D6 polymorphism on basic brain function. This review summarizes evidence on the effect of DME polymorphisms on brain function that adds to the well-known effects of DME polymorphisms on pharmacokinetics in explaining the range of phenotypes that are relevant to psychiatric practice.
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Jiang XL, Shen HW, Mager DE, Yu AM. Pharmacokinetic interactions between monoamine oxidase A inhibitor harmaline and 5-methoxy-N,N-dimethyltryptamine, and the impact of CYP2D6 status. Drug Metab Dispos 2013; 41:975-86. [PMID: 23393220 DOI: 10.1124/dmd.112.050724] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT or street name "5-MEO") is a newer designer drug belonging to a group of naturally occurring indolealkylamines. Our recent study has demonstrated that coadministration of monoamine oxidase A (MAO-A) inhibitor harmaline (5 mg/kg) increases systemic exposure to 5-MeO-DMT (2 mg/kg) and active metabolite bufotenine. This study is aimed at delineating harmaline and 5-MeO-DMT pharmacokinetic (PK) interactions at multiple dose levels, as well as the impact of CYP2D6 that affects harmaline PK and determines 5-MeO-DMT O-demethylation to produce bufotenine. Our data revealed that inhibition of MAO-A-mediated metabolic elimination by harmaline (2, 5, and 15 mg/kg) led to a sharp increase in systemic and cerebral exposure to 5-MeO-DMT (2 and 10 mg/kg) at all dose combinations. A more pronounced effect on 5-MeO-DMT PK was associated with greater exposure to harmaline in wild-type mice than CYP2D6-humanized (Tg-CYP2D6) mice. Harmaline (5 mg/kg) also increased blood and brain bufotenine concentrations that were generally higher in Tg-CYP2D6 mice. Surprisingly, greater harmaline dose (15 mg/kg) reduced bufotenine levels. The in vivo inhibitory effect of harmaline on CYP2D6-catalyzed bufotenine formation was confirmed by in vitro study using purified CYP2D6. Given these findings, a unified PK model including the inhibition of MAO-A- and CYP2D6-catalyzed 5-MeO-DMT metabolism by harmaline was developed to describe blood harmaline, 5-MeO-DMT, and bufotenine PK profiles in both wild-type and Tg-CYP2D6 mouse models. This PK model may be further employed to predict harmaline and 5-MeO-DMT PK interactions at various doses, define the impact of CYP2D6 status, and drive harmaline-5-MeO-DMT pharmacodynamics.
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Affiliation(s)
- Xi-Ling Jiang
- Department of Pharmaceutical Sciences, University at Buffalo, The State University of New York, Buffalo, New York, USA
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