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Rakoczy RJ, Runge GN, Sen AK, Sandoval O, Wells HG, Nguyen Q, Roberts BR, Sciortino JH, Gibbons WJ, Friedberg LM, Jones JA, McMurray MS. Pharmacological and behavioural effects of tryptamines present in psilocybin-containing mushrooms. Br J Pharmacol 2024. [PMID: 38825326 DOI: 10.1111/bph.16466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 05/08/2024] [Indexed: 06/04/2024] Open
Abstract
BACKGROUND AND PURPOSE Demand for new antidepressants has resulted in a re-evaluation of the therapeutic potential of psychedelic drugs. Several tryptamines found in psilocybin-containing "magic" mushrooms share chemical similarities with psilocybin. Early work suggests they may share biological targets. However, few studies have explored their pharmacological and behavioural effects. EXPERIMENTAL APPROACH We compared baeocystin, norbaeocystin and aeruginascin with psilocybin to determine if they are metabolized by the same enzymes, similarly penetrate the blood-brain barrier, serve as ligands for similar receptors and modulate behaviour in rodents similarly. We also assessed the stability and optimal storage and handling conditions for each compound. KEY RESULTS In vitro enzyme kinetics assays found that all compounds had nearly identical rates of dephosphorylation via alkaline phosphatase and metabolism by monoamine oxidase. Further, we found that only the dephosphorylated products of baeocystin and norbaeocystin crossed a blood-brain barrier mimetic to a similar degree as the dephosphorylated form of psilocybin, psilocin. The dephosphorylated form of norbaeocystin was found to activate the 5-HT2A receptor with similar efficacy to psilocin and norpsilocin in in vitro cell imaging assays. Behaviourally, only psilocybin induced head twitch responses in rats, a marker of 5-HT2A-mediated psychedelic effects and hallucinogenic potential. However, like psilocybin, norbaeocystin improved outcomes in the forced swim test. All compounds caused minimal changes to metrics of renal and hepatic health, suggesting innocuous safety profiles. CONCLUSIONS AND IMPLICATIONS Collectively, this work suggests that other naturally occurring tryptamines, especially norbaeocystin, may share overlapping therapeutic potential with psilocybin, but without causing hallucinations.
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Affiliation(s)
- Ryan J Rakoczy
- Department of Psychology, Miami University, Oxford, Ohio, USA
| | - Grace N Runge
- Department of Psychology, Miami University, Oxford, Ohio, USA
| | - Abhishek K Sen
- Department of Chemical, Paper, and Biomedical Engineering, Miami University, Oxford, Ohio, USA
| | - Oscar Sandoval
- Department of Psychology, Miami University, Oxford, Ohio, USA
| | - Hunter G Wells
- Department of Psychology, Miami University, Oxford, Ohio, USA
| | - Quynh Nguyen
- Department of Chemical, Paper, and Biomedical Engineering, Miami University, Oxford, Ohio, USA
| | | | - Jon H Sciortino
- Department of Psychology, Miami University, Oxford, Ohio, USA
| | - William J Gibbons
- Department of Chemical, Paper, and Biomedical Engineering, Miami University, Oxford, Ohio, USA
| | - Lucas M Friedberg
- Department of Chemical, Paper, and Biomedical Engineering, Miami University, Oxford, Ohio, USA
| | - J Andrew Jones
- Department of Chemical, Paper, and Biomedical Engineering, Miami University, Oxford, Ohio, USA
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Holze F, Singh N, Liechti ME, D'Souza DC. Serotonergic Psychedelics: A Comparative Review of Efficacy, Safety, Pharmacokinetics, and Binding Profile. BIOLOGICAL PSYCHIATRY. COGNITIVE NEUROSCIENCE AND NEUROIMAGING 2024; 9:472-489. [PMID: 38301886 DOI: 10.1016/j.bpsc.2024.01.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 12/27/2023] [Accepted: 01/22/2024] [Indexed: 02/03/2024]
Abstract
Psychedelic compounds, including psilocybin, LSD (lysergic acid diethylamide), DMT (N,N -dimethyltryptamine), and 5-MeO-DMT (5-methoxy-N,N-dimethyltryptamine), all of which are serotonin 2A receptor agonists, are being investigated as potential treatments. This review aims to summarize the current clinical research on these 4 compounds and mescaline to guide future research. Their mechanism(s) of action, pharmacokinetics, pharmacodynamics, efficacy, and safety were reviewed. While evidence for therapeutic indications, with the exception of psilocybin for depression, is still relatively scarce, we noted no differences in psychedelic effects beyond effect duration. Therefore, it remains unclear whether different receptor profiles contribute to the therapeutic potential of these compounds. More research is needed to differentiate these compounds in order to inform which compounds might be best for different therapeutic uses.
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Affiliation(s)
- Friederike Holze
- Division of Clinical Pharmacology and Toxicology, Department of Biomedicine and Department of Clinical Research, University Hospital Basel, University of Basel, Basel, Switzerland; Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland.
| | - Nirmal Singh
- Department of Psychiatry, Yale School of Medicine, New Haven, Connecticut; Clinical Neuroscience Research Unit, Connecticut Mental Health Center, New Haven, Connecticut
| | - Matthias E Liechti
- Division of Clinical Pharmacology and Toxicology, Department of Biomedicine and Department of Clinical Research, University Hospital Basel, University of Basel, Basel, Switzerland; Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Deepak Cyril D'Souza
- Department of Psychiatry, Yale School of Medicine, New Haven, Connecticut; Clinical Neuroscience Research Unit, Connecticut Mental Health Center, New Haven, Connecticut; VA Connecticut Healthcare System, West Haven, Connecticut.
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3
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Thomann J, Kolaczynska KE, Stoeckmann OV, Rudin D, Vizeli P, Hoener MC, Pryce CR, Vollenweider FX, Liechti ME, Duthaler U. In vitro and in vivo metabolism of psilocybin's active metabolite psilocin. Front Pharmacol 2024; 15:1391689. [PMID: 38741590 PMCID: PMC11089204 DOI: 10.3389/fphar.2024.1391689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 04/08/2024] [Indexed: 05/16/2024] Open
Abstract
In vivo, psilocybin is rapidly dephosphorylated to psilocin which induces psychedelic effects by interacting with the 5-HT2A receptor. Psilocin primarily undergoes glucuronidation or conversion to 4-hydroxyindole-3-acetic acid (4-HIAA). Herein, we investigated psilocybin's metabolic pathways in vitro and in vivo, conducting a thorough analysis of the enzymes involved. Metabolism studies were performed using human liver microsomes (HLM), cytochrome P450 (CYP) enzymes, monoamine oxidase (MAO), and UDP-glucuronosyltransferase (UGT). In vivo, metabolism was examined using male C57BL/6J mice and human plasma samples. Approximately 29% of psilocin was metabolized by HLM, while recombinant CYP2D6 and CYP3A4 enzymes metabolized nearly 100% and 40% of psilocin, respectively. Notably, 4-HIAA and 4-hydroxytryptophol (4-HTP) were detected with HLM but not with recombinant CYPs. MAO-A transformed psilocin into minimal amounts of 4-HIAA and 4-HTP. 4-HTP was only present in vitro. Neither 4-HIAA nor 4-HTP showed relevant interactions at assessed 5-HT receptors. In contrast to in vivo data, UGT1A10 did not extensively metabolize psilocin in vitro. Furthermore, two putative metabolites were observed. N-methyl-4-hydroxytryptamine (norpsilocin) was identified in vitro (CYP2D6) and in mice, while an oxidized metabolite was detected in vitro (CYP2D6) and in humans. However, the CYP2D6 genotype did not influence psilocin plasma concentrations in the investigated study population. In conclusion, MAO-A, CYP2D6, and CYP3A4 are involved in psilocin's metabolism. The discovery of putative norpsilocin in mice and oxidized psilocin in humans further unravels psilocin's metabolism. Despite limitations in replicating phase II metabolism in vitro, these findings hold significance for studying drug-drug interactions and advancing research on psilocybin as a therapeutic agent.
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Affiliation(s)
- Jan Thomann
- Division of Clinical Pharmacology and Toxicology, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
- Division of Clinical Pharmacology and Toxicology, Department of Biomedicine, University Hospital Basel, Basel, Switzerland
| | - Karolina E. Kolaczynska
- Division of Clinical Pharmacology and Toxicology, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
- Division of Clinical Pharmacology and Toxicology, Department of Biomedicine, University Hospital Basel, Basel, Switzerland
| | - Oliver V. Stoeckmann
- Division of Clinical Pharmacology and Toxicology, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
- Division of Clinical Pharmacology and Toxicology, Department of Biomedicine, University Hospital Basel, Basel, Switzerland
| | - Deborah Rudin
- Division of Clinical Pharmacology and Toxicology, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
- Division of Clinical Pharmacology and Toxicology, Department of Biomedicine, University Hospital Basel, Basel, Switzerland
| | - Patrick Vizeli
- Division of Clinical Pharmacology and Toxicology, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
- Division of Clinical Pharmacology and Toxicology, Department of Biomedicine, University Hospital Basel, Basel, Switzerland
| | - Marius C. Hoener
- Neuroscience Research, Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Christopher R. Pryce
- Department of Psychiatry, Psychotherapy and Psychosomatics, Preclinical Laboratory for Translational Research Into Affective Disorders, University of Zurich, Zurich, Switzerland
| | - Franz X. Vollenweider
- Department of Psychiatry, Psychotherapy and Psychosomatics, Neurophenomenology and Consciousness, University of Zurich, Zurich, Switzerland
| | - Matthias E. Liechti
- Division of Clinical Pharmacology and Toxicology, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
- Division of Clinical Pharmacology and Toxicology, Department of Biomedicine, University Hospital Basel, Basel, Switzerland
| | - Urs Duthaler
- Division of Clinical Pharmacology and Toxicology, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
- Division of Clinical Pharmacology and Toxicology, Department of Biomedicine, University Hospital Basel, Basel, Switzerland
- Institute of Forensic Medicine, Department of Biomedical Engineering, University of Basel, Basel, Switzerland
- Institute of Forensic Medicine, Health Department Basel-Stadt, Basel, Switzerland
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Kelly TJ, Bonniwell EM, Mu L, Liu X, Hu Y, Friedman V, Yu H, Su W, McCorvy JD, Liu QS. Psilocybin analog 4-OH-DiPT enhances fear extinction and GABAergic inhibition of principal neurons in the basolateral amygdala. Neuropsychopharmacology 2024; 49:854-863. [PMID: 37752222 PMCID: PMC10948882 DOI: 10.1038/s41386-023-01744-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 08/08/2023] [Accepted: 09/12/2023] [Indexed: 09/28/2023]
Abstract
Psychedelics such as psilocybin show great promise for the treatment of depression and PTSD, but their long duration of action poses practical limitations for patient access. 4-OH-DiPT is a fast-acting and shorter-lasting derivative of psilocybin. Here we characterized the pharmacological profile of 4-OH-DiPT and examined its impact on fear extinction learning as well as a potential mechanism of action. First, we profiled 4-OH-DiPT at all 12 human 5-HT GPCRs. 4-OH-DiPT showed strongest agonist activity at all three 5-HT2A/2B/2C receptors with near full agonist activity at 5-HT2A. Notably, 4-OH-DiPT had comparable activity at mouse and human 5-HT2A/2B/2C receptors. In a fear extinction paradigm, 4-OH-DiPT significantly reduced freezing responses to conditioned cues in a dose-dependent manner with a greater potency in female mice than male mice. Female mice that received 4-OH-DiPT before extinction training had reduced avoidance behaviors several days later in the light dark box, elevated plus maze and novelty-suppressed feeding test compared to controls, while male mice did not show significant differences. 4-OH-DiPT produced robust increases in spontaneous inhibitory postsynaptic currents (sIPSCs) in basolateral amygdala (BLA) principal neurons and action potential firing in BLA interneurons in a 5-HT2A-dependent manner. RNAscope demonstrates that Htr2a mRNA is expressed predominantly in BLA GABA interneurons, Htr2c mRNA is expressed in both GABA interneurons and principal neurons, while Htr2b mRNA is absent in the BLA. Our findings suggest that 4-OH-DiPT activates BLA interneurons via the 5-HT2A receptor to enhance GABAergic inhibition of BLA principal neurons, which provides a potential mechanism for suppressing learned fear.
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Affiliation(s)
- Thomas J Kelly
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Emma M Bonniwell
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Lianwei Mu
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Xiaojie Liu
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Ying Hu
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Vladislav Friedman
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Hao Yu
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Wantang Su
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - John D McCorvy
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI, 53226, USA.
| | - Qing-Song Liu
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA.
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Funk D, Araujo J, Slassi M, Lanthier J, Atkinson J, Feng D, Lau W, Lê A, Higgins GA. Effect of a single psilocybin treatment on Fos protein expression in male rat brain. Neuroscience 2024; 539:1-11. [PMID: 38184069 DOI: 10.1016/j.neuroscience.2024.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Revised: 12/31/2023] [Accepted: 01/02/2024] [Indexed: 01/08/2024]
Abstract
Psilocybin has received attention as a treatment for depression, stress disorders and drug and alcohol addiction. To help determine the mechanisms underlying its therapeutic effects, here we examined acute effects of a range of behaviourally relevant psilocybin doses (0.1-3 mg/kg SC) on regional expression of Fos, the protein product of the immediate early gene, c-fos in brain areas involved in stress, reward and motivation in male rats. We also determined the cellular phenotypes activated by psilocybin, in a co-labeling analysis with NeuN, a marker of mature neurons, or Olig1, a marker of oligodendrocytes. In adult male Sprague-Dawley rats, psilocybin increased Fos expression dose dependently in several brain regions, including the frontal cortex, nucleus accumbens, central and basolateral amygdala and locus coeruleus. These effects were most marked in the central amygdala. Double labeling experiments showed that Fos was expressed in both neurons and oligodendrocytes. These results extend previous research by determining Fos expression in multiple brain areas at a wider psilocybin dose range, and the cellular phenotypes expressing Fos. The data also highlight the amygdala, especially the central nucleus, a key brain region involved in emotional processing and learning and interconnected with other brain areas involved in stress, reward and addiction, as a potentially important locus for the therapeutic effects of psilocybin. Overall, the present findings suggest that the central amygdala may be an important site through which the initial brain activation induced by psilocybin is translated into neuroplastic changes, locally and in other regions that underlie its extended therapeutic effects.
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Affiliation(s)
- Douglas Funk
- Campbell Family Research Institute, Centre for Addiction and Mental Health, Toronto M5S 2S1, Canada.
| | - Joseph Araujo
- Transpharmation Ltd., Fergus N1M 2W8, Canada; Mindset Pharma, Toronto M5V 0R2, Canada
| | | | | | | | - Daniel Feng
- Transpharmation Ltd., Fergus N1M 2W8, Canada
| | - Winnie Lau
- Transpharmation Ltd., Fergus N1M 2W8, Canada
| | - Anh Lê
- Campbell Family Research Institute, Centre for Addiction and Mental Health, Toronto M5S 2S1, Canada; Department of Pharmacology and Toxicology, University of Toronto, Toronto M5S 1A8, Canada
| | - Guy A Higgins
- Transpharmation Ltd., Fergus N1M 2W8, Canada; Department of Pharmacology and Toxicology, University of Toronto, Toronto M5S 1A8, Canada
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6
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Jones NT, Wagner L, Hahn MCP, Scarlett CO, Wenthur CJ. In vivo validation of psilacetin as a prodrug yielding modestly lower peripheral psilocin exposure than psilocybin. Front Psychiatry 2024; 14:1303365. [PMID: 38264637 PMCID: PMC10804612 DOI: 10.3389/fpsyt.2023.1303365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 11/17/2023] [Indexed: 01/25/2024] Open
Abstract
Introduction The use of the psychedelic compound psilocybin in conjunction with psychotherapy has shown promising results in the treatment of psychiatric disorders, though the underlying mechanisms supporting these effects remain unclear. Psilocybin is a Schedule I substance that is dephosphorylated in vivo to form an active metabolite, psilocin. Psilacetin, also known as O-acetylpsilocin or 4-acetoxy-N,N-dimethyltryptamine (4-AcO-DMT), is an unscheduled compound that has long been suggested as an alternative psilocin prodrug, though direct in vivo support for this hypothesis has thus far been lacking. Methods This study employed liquid chromatography-tandem mass spectrometry (LC-MS/MS) to assess the time-course and plasma concentrations of psilocin following the intraperitoneal (IP) administration of psilacetin fumarate or psilocybin to male and female C57Bl6/J mice. Results Direct comparisons of the time courses for psilocin exposure arising from psilocybin and psilacetin found that psilocybin led to 10-25% higher psilocin concentrations than psilacetin at 15-min post-injection. The half-life of psilocin remained approximately 30 min, irrespective of whether it came from psilocybin or psilacetin. Overall, the relative amount of psilocin exposure from psilacetin fumarate was found to be approximately 70% of that from psilocybin. Discussion These findings provide the first direct support for the long-standing assumption in the field that psilacetin functions as a prodrug for psilocin in vivo. In addition, these results indicate that psilacetin fumarate results in lower peripheral psilocin exposure than psilocybin when dosed on an equimolar basis. Thoughtful substitution of psilocybin with psilacetin fumarate appears to be a viable approach for conducting mechanistic psychedelic research in C57Bl6/J mice.
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Affiliation(s)
- Nathan T. Jones
- School of Pharmacy, University of Wisconsin-Madison, Madison, WI, United States
| | - Laura Wagner
- School of Pharmacy, University of Wisconsin-Madison, Madison, WI, United States
| | - Molly C. Pellitteri Hahn
- Analytical Instrumentation Center, School of Pharmacy, University of Wisconsin-Madison, Madison, WI, United States
| | - Cameron O. Scarlett
- Analytical Instrumentation Center, School of Pharmacy, University of Wisconsin-Madison, Madison, WI, United States
| | - Cody J. Wenthur
- School of Pharmacy, Transdisciplinary Center for Research in Psychoactive Substances, University of Wisconsin-Madison, Madison, WI, United States
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Holze F, Erne L, Duthaler U, Liechti ME. Pharmacokinetics, pharmacodynamics and urinary recovery of oral lysergic acid diethylamide administration in healthy participants. Br J Clin Pharmacol 2024; 90:200-208. [PMID: 37596682 DOI: 10.1111/bcp.15887] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 07/24/2023] [Accepted: 08/05/2023] [Indexed: 08/20/2023] Open
Abstract
AIMS Lysergic acid diethylamide (LSD) is currently investigated for several neurological and psychiatric illnesses. Various studies have investigated the pharmacokinetics and the pharmacokinetic-pharmacodynamic relationship of LSD in healthy participants, but data on urinary recovery and confirmatory studies are missing. METHODS The present study characterized the pharmacokinetics, pharmacokinetic-pharmacodynamic relationship and urinary recovery of LSD at doses of 85 and 170 μg administered orally in 28 healthy participants. The plasma concentrations and subjective effects of LSD were continuously evaluated over a period of 24 h. Urine was collected during 3 time intervals (0-8, 8-16 and 16-24 h after LSD administration). Pharmacokinetic parameters were determined using compartmental modelling. Concentration-subjective effect relationships were described using pharmacokinetic-pharmacodynamic modelling. RESULTS Mean (95% confidence interval) maximal LSD concentrations were 1.8 ng/mL (1.6-2.0) and 3.4 ng/mL (3.0-3.8) after the administration of 85 and 170 μg LSD, respectively. Maximal concentrations were achieved on average after 1.7 h. Elimination half-lives were 3.7 h (3.4-4.1) and 4.0 h (3.6-4.4), for 85 and 170 μg LSD, respectively. Only 1% of the administered dose was recovered from urine unchanged within the first 24 h, 16% was eliminated as 2-oxo-3-hydroxy-LSD. Urinary recovery was dose proportional. Mean (±standard deviation) durations of subjective effects were 9.3 ± 3.2 and 11 ± 3.7 h, and maximal effects (any drug effects) were 77 ± 18% and 87 ± 13% after 85 and 170 μg of LSD, respectively. CONCLUSION The present novel study validates previous findings. LSD exhibited dose-proportional pharmacokinetics and first-order elimination kinetics and dose-dependent duration and intensity of subjective effects. LSD is extensively metabolized and shows dose-proportional urinary recovery.
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Affiliation(s)
- Friederike Holze
- Clinical Pharmacology and Toxicology, Department of Biomedicine and Department of Clinical Research, University Hospital Basel and University of Basel, Basel, Switzerland
- Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Livio Erne
- Clinical Pharmacology and Toxicology, Department of Biomedicine and Department of Clinical Research, University Hospital Basel and University of Basel, Basel, Switzerland
- Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Urs Duthaler
- Clinical Pharmacology and Toxicology, Department of Biomedicine and Department of Clinical Research, University Hospital Basel and University of Basel, Basel, Switzerland
- Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Matthias E Liechti
- Clinical Pharmacology and Toxicology, Department of Biomedicine and Department of Clinical Research, University Hospital Basel and University of Basel, Basel, Switzerland
- Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
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8
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Rieser NM, Gubser LP, Moujaes F, Duerler P, Lewis CR, Michels L, Vollenweider FX, Preller KH. Psilocybin-induced changes in cerebral blood flow are associated with acute and baseline inter-individual differences. Sci Rep 2023; 13:17475. [PMID: 37838755 PMCID: PMC10576760 DOI: 10.1038/s41598-023-44153-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 10/04/2023] [Indexed: 10/16/2023] Open
Abstract
Research into the use of psilocybin for the treatment of psychiatric disorders is a growing field. Nevertheless, robust brain-behavior relationships linking psilocybin-induced brain changes to subjective drug-induced effects have not been established. Furthermore, it is unclear if the acute neural effects are dependent on individual heterogeneity in baseline characteristics. To address this, we assessed the effects of three oral doses of psilocybin vs. placebo on cerebral blood flow (CBF) using arterial spin labeling in healthy participants (N = 70; n = 31, 0.16 mg/kg; n = 10, 0.2 mg/kg; n = 29, 0.215 mg/kg). First, we quantified psilocybin-induced changes in relative and absolute CBF. Second, in an exploratory analysis, we assessed whether individual baseline characteristics and subjective psychedelic experience are associated with changes in CBF. Psychological and neurobiological baseline characteristics correlated with the psilocybin-induced reduction in relative CBF and the psilocybin-induced subjective experience. Furthermore, the psilocybin-induced subjective experience was associated with acute changes in relative and absolute CBF. The results demonstrated that inter-individual heterogeneity in the neural response to psilocybin is associated with baseline characteristics and shed light on the mechanisms underlying the psychedelic-induced altered state. Overall, these findings help guide the search for biomarkers, paving the way for a personalized medicine approach within the framework of psychedelic-assisted therapy.
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Affiliation(s)
- Nathalie M Rieser
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital Zurich, Lenggstrasse 31, Zurich, Switzerland.
| | - Ladina P Gubser
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital Zurich, Lenggstrasse 31, Zurich, Switzerland
| | - Flora Moujaes
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital Zurich, Lenggstrasse 31, Zurich, Switzerland
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, 06510, USA
| | - Patricia Duerler
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital Zurich, Lenggstrasse 31, Zurich, Switzerland
| | - Candace R Lewis
- School of Life Sciences, Arizona State University, Tempe, AZ, 85281, USA
| | - Lars Michels
- Department of Neuroradiology, University Hospital Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and Swiss Federal Institute of Technology Zurich, Zurich, Switzerland
| | - Franz X Vollenweider
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital Zurich, Lenggstrasse 31, Zurich, Switzerland
| | - Katrin H Preller
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital Zurich, Lenggstrasse 31, Zurich, Switzerland
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9
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Domanegg K, Sommer WH, Meinhardt MW. Psychedelic Targeting of Metabotropic Glutamate Receptor 2 and Its Implications for the Treatment of Alcoholism. Cells 2023; 12:963. [PMID: 36980303 PMCID: PMC10047550 DOI: 10.3390/cells12060963] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 03/16/2023] [Accepted: 03/20/2023] [Indexed: 03/30/2023] Open
Abstract
Alcohol abuse is a leading risk factor for the public health burden worldwide. Approved pharmacotherapies have demonstrated limited effectiveness over the last few decades in treating alcohol use disorders (AUD). New therapeutic approaches are therefore urgently needed. Historical and recent clinical trials using psychedelics in conjunction with psychotherapy demonstrated encouraging results in reducing heavy drinking in AUD patients, with psilocybin being the most promising candidate. While psychedelics are known to induce changes in gene expression and neuroplasticity, we still lack crucial information about how this specifically counteracts the alterations that occur in neuronal circuits throughout the course of addiction. This review synthesizes well-established knowledge from addiction research about pathophysiological mechanisms related to the metabotropic glutamate receptor 2 (mGlu2), with findings and theories on how mGlu2 connects to the major signaling pathways induced by psychedelics via serotonin 2A receptors (2AR). We provide literature evidence that mGlu2 and 2AR are able to regulate each other's downstream signaling pathways, either through monovalent crosstalk or through the formation of a 2AR-mGlu2 heteromer, and highlight epigenetic mechanisms by which 2ARs can modulate mGlu2 expression. Lastly, we discuss how these pathways might be targeted therapeutically to restore mGlu2 function in AUD patients, thereby reducing the propensity to relapse.
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Affiliation(s)
- Kevin Domanegg
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, 69115 Heidelberg, Germany
| | - Wolfgang H. Sommer
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, 69115 Heidelberg, Germany
- Bethanien Hospital for Psychiatry, Psychosomatics, and Psychotherapy Greifswald, 17489 Greifswald, Germany
| | - Marcus W. Meinhardt
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, 69115 Heidelberg, Germany
- Department of Molecular Neuroimaging, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, 69115 Heidelberg, Germany
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Sudakin DL. Psilocybin services in Oregon: a call for awareness among clinical toxicologists. Clin Toxicol (Phila) 2023; 61:143-145. [PMID: 36815350 DOI: 10.1080/15563650.2023.2182664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
BACKGROUND In 2023, Oregon enacted laws regulating the manufacture and use of psilocybin products in licensed facilities for supervised sessions with trained facilitators. COMMENTARY This commentary summarizes the final rules for psilocybin services in Oregon, and provides perspectives from a clinical toxicologist on some of the issues that may arise. These include the scope of practice for non-clinical facilitators, prevention and management of adverse drug reactions, and toxicological uncertainties with regards to dose considerations for people with mental health and other medical conditions. CONCLUSION This commentary addresses some common misperceptions relating to the program, and provides perspective on some of the challenges that clinical toxicologists may encounter as legislative reform initiatives for psilocybin move forward throughout the United States.
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