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Danyeli LV, Sen ZD, Colic L, Opel N, Refisch A, Blekic N, Macharadze T, Kretzschmar M, Munk MJ, Gaser C, Speck O, Walter M, Li M. Cortical thickness of the posterior cingulate cortex is associated with the ketamine-induced altered sense of self: An ultra-high field MRI study. J Psychiatr Res 2024; 172:136-143. [PMID: 38382237 DOI: 10.1016/j.jpsychires.2024.02.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 01/31/2024] [Accepted: 02/07/2024] [Indexed: 02/23/2024]
Abstract
Subanesthetic doses of ketamine induce an antidepressant effect within hours in individuals with treatment-resistant depression while it furthermore induces immediate but transient psychotomimetic effects. Among these psychotomimetic effects, an altered sense of self has specifically been associated with the antidepressant response to ketamine as well as psychedelics. However, there is plenty of variation in the extent of the drug-induced altered sense of self experience that might be explained by differences in basal morphological characteristics, such as cortical thickness. Regions that have been previously associated with a psychedelics-induced sense of self and with ketamine's mechanism of action, are the posterior cingulate cortex (PCC) and the pregenual anterior cingulate cortex (pgACC). In this randomized, placebo-controlled, double-blind cross-over magnetic resonance imaging study, thirty-five healthy male participants (mean age ± standard deviation (SD) = 25.1 ± 4.2 years) were scanned at 7 T. We investigated whether the cortical thickness of two DMN regions, the PCC and the pgACC, are associated with disembodiment and experience of unity scores, which were used to index the ketamine-induced altered sense of self. We observed a negative correlation between the PCC cortical thickness and the disembodiment scores (R = -0.54, p < 0.001). In contrast, no significant association was found between the pgACC cortical thickness and the ketamine-induced altered sense of self. In the context of the existing literature, our findings highlight the importance of the PCC as a structure involved in the mechanism of ketamine-induced altered sense of self that seems to be shared with different antidepressant agents with psychotomimetic effects operating on different classes of transmitter systems.
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Affiliation(s)
- Lena Vera Danyeli
- Department of Psychiatry and Psychotherapy, Jena University Hospital, Jena, Germany; Clinical Affective Neuroimaging Laboratory (CANLAB), Magdeburg, Germany; Department of Psychiatry and Psychotherapy, University Tübingen, Tübingen, Germany; Center for Intervention and Research on adaptive and maladaptive brain Circuits underlying mental health (C-I-R-C), Halle-Jena-Magdeburg, Germany
| | - Zümrüt Duygu Sen
- Department of Psychiatry and Psychotherapy, Jena University Hospital, Jena, Germany; Clinical Affective Neuroimaging Laboratory (CANLAB), Magdeburg, Germany; Center for Intervention and Research on adaptive and maladaptive brain Circuits underlying mental health (C-I-R-C), Halle-Jena-Magdeburg, Germany
| | - Lejla Colic
- Department of Psychiatry and Psychotherapy, Jena University Hospital, Jena, Germany; Center for Intervention and Research on adaptive and maladaptive brain Circuits underlying mental health (C-I-R-C), Halle-Jena-Magdeburg, Germany; German Center for Mental Health (DZPG), partner site Halle-Jena-Magdeburg, Germany
| | - Nils Opel
- Department of Psychiatry and Psychotherapy, Jena University Hospital, Jena, Germany; Center for Intervention and Research on adaptive and maladaptive brain Circuits underlying mental health (C-I-R-C), Halle-Jena-Magdeburg, Germany; German Center for Mental Health (DZPG), partner site Halle-Jena-Magdeburg, Germany
| | - Alexander Refisch
- Department of Psychiatry and Psychotherapy, Jena University Hospital, Jena, Germany; Center for Intervention and Research on adaptive and maladaptive brain Circuits underlying mental health (C-I-R-C), Halle-Jena-Magdeburg, Germany
| | - Nikolai Blekic
- Department of Psychiatry and Psychotherapy, Jena University Hospital, Jena, Germany; Clinical Affective Neuroimaging Laboratory (CANLAB), Magdeburg, Germany
| | - Tamar Macharadze
- Department of Anesthesiology and Intensive Care Medicine, Medical Faculty, Otto-von-Guericke University Magdeburg, Magdeburg, Germany; Department Systems Physiology of Learning, Leibniz Institute for Neurobiology, Magdeburg, Germany; Center for Behavioral Brain Sciences, Magdeburg, Germany; Department of Behavioral Neurology, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Moritz Kretzschmar
- Department of Anesthesiology and Intensive Care Medicine, Medical Faculty, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
| | - MatthiasH J Munk
- Department of Psychiatry and Psychotherapy, University Tübingen, Tübingen, Germany; Systems Neurophysiology, Department of Biology, Darmstadt University of Technology, Darmstadt, Germany
| | - Christian Gaser
- Department of Psychiatry and Psychotherapy, Jena University Hospital, Jena, Germany; Center for Intervention and Research on adaptive and maladaptive brain Circuits underlying mental health (C-I-R-C), Halle-Jena-Magdeburg, Germany; German Center for Mental Health (DZPG), partner site Halle-Jena-Magdeburg, Germany; Department of Neurology, Jena University Hospital, Jena, Germany
| | - Oliver Speck
- Center for Intervention and Research on adaptive and maladaptive brain Circuits underlying mental health (C-I-R-C), Halle-Jena-Magdeburg, Germany; German Center for Mental Health (DZPG), partner site Halle-Jena-Magdeburg, Germany; Center for Behavioral Brain Sciences, Magdeburg, Germany; Department of Behavioral Neurology, Leibniz Institute for Neurobiology, Magdeburg, Germany; Department of Biomedical Magnetic Resonance, Otto-von-Guericke University Magdeburg, Magdeburg, Germany
| | - Martin Walter
- Department of Psychiatry and Psychotherapy, Jena University Hospital, Jena, Germany; Clinical Affective Neuroimaging Laboratory (CANLAB), Magdeburg, Germany; Department of Psychiatry and Psychotherapy, University Tübingen, Tübingen, Germany; Center for Intervention and Research on adaptive and maladaptive brain Circuits underlying mental health (C-I-R-C), Halle-Jena-Magdeburg, Germany; German Center for Mental Health (DZPG), partner site Halle-Jena-Magdeburg, Germany; Center for Behavioral Brain Sciences, Magdeburg, Germany; Department of Behavioral Neurology, Leibniz Institute for Neurobiology, Magdeburg, Germany.
| | - Meng Li
- Department of Psychiatry and Psychotherapy, Jena University Hospital, Jena, Germany; Clinical Affective Neuroimaging Laboratory (CANLAB), Magdeburg, Germany; Center for Intervention and Research on adaptive and maladaptive brain Circuits underlying mental health (C-I-R-C), Halle-Jena-Magdeburg, Germany.
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Buchborn T, Kettner HS, Kärtner L, Meinhardt MW. The ego in psychedelic drug action - ego defenses, ego boundaries, and the therapeutic role of regression. Front Neurosci 2023; 17:1232459. [PMID: 37869510 PMCID: PMC10587586 DOI: 10.3389/fnins.2023.1232459] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 08/18/2023] [Indexed: 10/24/2023] Open
Abstract
The ego is one of the most central psychological constructs in psychedelic research and a key factor in psychotherapy, including psychedelic-assisted forms of psychotherapy. Despite its centrality, the ego-construct remains ambiguous in the psychedelic literature. Therefore, we here review the theoretical background of the ego-construct with focus on its psychodynamic conceptualization. We discuss major functions of the ego including ego boundaries, defenses, and synthesis, and evaluate the role of the ego in psychedelic drug action. According to the psycholytic paradigm, psychedelics are capable of inducing regressed states of the ego that are less protected by the ego's usual defensive apparatus. In such states, core early life conflicts may emerge that have led to maladaptive ego patterns. We use the psychodynamic term character in this paper as a potential site of change and rearrangement; character being the chronic and habitual patterns the ego utilizes to adapt to the everyday challenges of life, including a preferred set of defenses. We argue that in order for psychedelic-assisted therapy to successfully induce lasting changes to the ego's habitual patterns, it must psycholytically permeate the characterological core of the habits. The primary working principle of psycholytic therapy therefore is not the state of transient ego regression alone, but rather the regressively favored emotional integration of those early life events that have shaped the foundation, development, and/or rigidification of a person's character - including his or her defense apparatus. Aiming for increased flexibility of habitual ego patterns, the psycholytic approach is generally compatible with other forms of psychedelic-assisted therapy, such as third wave cognitive behavioral approaches.
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Affiliation(s)
- Tobias Buchborn
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Hannes S. Kettner
- Centre for Psychedelic Research, Department of Medicine, Imperial College London, London, United Kingdom
- Psychedelics Division, Neuroscape, Department of Neurology, University of California, San Francisco, San Francisco, CA, United States
| | - Laura Kärtner
- Centre for Psychedelic Research, Department of Medicine, Imperial College London, London, United Kingdom
- Department of Molecular Neuroimaging, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany
| | - Marcus W. Meinhardt
- Institute of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany
- Department of Molecular Neuroimaging, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Heidelberg, Germany
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3
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Jahanabadi S, Amiri S, Karkeh-Abadi M, Razmi A. Natural psychedelics in the treatment of depression; a review focusing on neurotransmitters. Fitoterapia 2023; 169:105620. [PMID: 37490982 DOI: 10.1016/j.fitote.2023.105620] [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: 04/04/2023] [Revised: 07/21/2023] [Accepted: 07/22/2023] [Indexed: 07/27/2023]
Abstract
Natural psychedelic compounds are emerging as potential novel therapeutics in psychiatry. This review will discuss how natural psychedelics exert their neurobiological therapeutic effects, and how different neurotransmission systems mediate the effects of these compounds. Further, current therapeutic strategies for depression, and novel mechanism of action of natural psychedelics in the treatment of depression will be discussed. In this review, our focus will be on N, N-dimethyltryptamine (DMT), reversible type A monoamine oxidase inhibitors, mescaline-containing cacti, psilocybin/psilocin-containing mushrooms, ibogaine, muscimol extracted from Amanita spp. mushrooms and ibotenic acid.
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Affiliation(s)
- Samane Jahanabadi
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Shahid Sadoughi University of Medical Sciences, Yazd, Iran; Pharmaceutical Science Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Shayan Amiri
- Division of Neurodegenerative Disorders, St Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB, Canada; Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, MB, Canada.
| | - Mehdi Karkeh-Abadi
- Medicinal Plants Research Center, Institute of Medicinal Plants, ACECR, Karaj, Iran
| | - Ali Razmi
- Medicinal Plants Research Center, Institute of Medicinal Plants, ACECR, Karaj, Iran.
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Ort A, Smallridge JW, Sarasso S, Casarotto S, von Rotz R, Casanova A, Seifritz E, Preller KH, Tononi G, Vollenweider FX. TMS-EEG and resting-state EEG applied to altered states of consciousness: oscillations, complexity, and phenomenology. iScience 2023; 26:106589. [PMID: 37138774 PMCID: PMC10149373 DOI: 10.1016/j.isci.2023.106589] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 12/22/2022] [Accepted: 04/03/2023] [Indexed: 05/05/2023] Open
Abstract
Exploring the neurobiology of the profound changes in consciousness induced by classical psychedelic drugs may require novel neuroimaging methods. Serotonergic psychedelic drugs such as psilocybin produce states of increased sensory-emotional awareness and arousal, accompanied by increased spontaneous electroencephalographic (EEG) signal diversity. By directly stimulating cortical tissue, the altered dynamics and propagation of the evoked EEG activity can reveal drug-induced changes in the overall brain state. We combine Transcranial Magnetic Stimulation (TMS) and EEG to reveal that psilocybin produces a state of increased chaotic brain activity which is not a result of altered complexity in the underlying causal interactions between brain regions. We also map the regional effects of psilocybin on TMS-evoked activity and identify changes in frontal brain structures that may be associated with the phenomenology of psychedelic experiences.
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Affiliation(s)
- Andres Ort
- Neurophenomenology of Consciousness Lab, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland
- Corresponding author
| | - John W. Smallridge
- Neurophenomenology of Consciousness Lab, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland
- Corresponding author
| | - Simone Sarasso
- Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy
| | - Silvia Casarotto
- Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy
- IRCCS Fondazione Don Carlo Gnocchi Milano, Milan, Italy
| | - Robin von Rotz
- Neurophenomenology of Consciousness Lab, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland
| | - Andrea Casanova
- Neurophenomenology of Consciousness Lab, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland
| | - Erich Seifritz
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland
| | - Katrin H. Preller
- Neurophenomenology of Consciousness Lab, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland
| | - Giulio Tononi
- Department of Psychiatry, University of Wisconsin, Madison, WI, USA
| | - Franz X. Vollenweider
- Neurophenomenology of Consciousness Lab, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland
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5
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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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6
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Psilocybin for Depression: From Credibility to Feasibility, What's Missing? Pharmaceuticals (Basel) 2022; 16:ph16010068. [PMID: 36678564 PMCID: PMC9861656 DOI: 10.3390/ph16010068] [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: 11/30/2022] [Revised: 12/28/2022] [Accepted: 12/29/2022] [Indexed: 01/03/2023] Open
Abstract
Psilocybin has been suggested as a promising transdiagnostic treatment strategy for a wide range of psychiatric disorders. Recent findings showed that psychedelic-assisted/"psycholitic" psychotherapy should provide significant and sustained alleviation of depressive symptoms. However, to date, there have been several study limitations (e.g., small sample sizes, blinding, limited follow-up, highly screened treatment populations) and some health/political issues, including practitioners' experience, lack of standardized protocols, psychedelics' legal status, ethical concerns, and potential psychological/psychopathological/medical untoward effects. The focus here is on a range of clinical and methodological issues, also aiming at outlining some possible suggestions. We are confident that newer evidence, more precise protocols, and eventual reclassification policies may allow a better understanding of the real potential of psilocybin as a transdiagnostic therapeutic molecule.
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Stoliker D, Egan GF, Friston KJ, Razi A. Neural Mechanisms and Psychology of Psychedelic Ego Dissolution. Pharmacol Rev 2022; 74:876-917. [PMID: 36786290 DOI: 10.1124/pharmrev.121.000508] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 06/26/2022] [Accepted: 06/29/2022] [Indexed: 11/22/2022] Open
Abstract
Neuroimaging studies of psychedelics have advanced our understanding of hierarchical brain organization and the mechanisms underlying their subjective and therapeutic effects. The primary mechanism of action of classic psychedelics is binding to serotonergic 5-HT2A receptors. Agonist activity at these receptors leads to neuromodulatory changes in synaptic efficacy that can have a profound effect on hierarchical message-passing in the brain. Here, we review the cognitive and neuroimaging evidence for the effects of psychedelics: in particular, their influence on selfhood and subject-object boundaries-known as ego dissolution-surmised to underwrite their subjective and therapeutic effects. Agonism of 5-HT2A receptors, located at the apex of the cortical hierarchy, may have a particularly powerful effect on sentience and consciousness. These effects can endure well after the pharmacological half-life, suggesting that psychedelics may have effects on neural plasticity that may play a role in their therapeutic efficacy. Psychologically, this may be accompanied by a disarming of ego resistance that increases the repertoire of perceptual hypotheses and affords alternate pathways for thought and behavior, including those that undergird selfhood. We consider the interaction between serotonergic neuromodulation and sentience through the lens of hierarchical predictive coding, which speaks to the value of psychedelics in understanding how we make sense of the world and specific predictions about effective connectivity in cortical hierarchies that can be tested using functional neuroimaging. SIGNIFICANCE STATEMENT: Classic psychedelics bind to serotonergic 5-HT2A receptors. Their agonist activity at these receptors leads to neuromodulatory changes in synaptic efficacy, resulting in a profound effect on information processing in the brain. Here, we synthesize an abundance of brain imaging research with pharmacological and psychological interpretations informed by the framework of predictive coding. Moreover, predictive coding is suggested to offer more sophisticated interpretations of neuroimaging findings by bridging the role between the 5-HT2A receptors and large-scale brain networks.
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Affiliation(s)
- Devon Stoliker
- Turner Institute for Brain and Mental Health (D.S., G.F.E., A.R.) and Monash Biomedical Imaging (G.F.E., A.R.), Monash University, Clayton, Victoria, Australia; Wellcome Centre for Human Neuroimaging, UCL, London, United Kingdom (K.J.F., A.R.); and CIFAR Azrieli Global Scholar, CIFAR, Toronto, Canada (A.R.)
| | - Gary F Egan
- Turner Institute for Brain and Mental Health (D.S., G.F.E., A.R.) and Monash Biomedical Imaging (G.F.E., A.R.), Monash University, Clayton, Victoria, Australia; Wellcome Centre for Human Neuroimaging, UCL, London, United Kingdom (K.J.F., A.R.); and CIFAR Azrieli Global Scholar, CIFAR, Toronto, Canada (A.R.)
| | - Karl J Friston
- Turner Institute for Brain and Mental Health (D.S., G.F.E., A.R.) and Monash Biomedical Imaging (G.F.E., A.R.), Monash University, Clayton, Victoria, Australia; Wellcome Centre for Human Neuroimaging, UCL, London, United Kingdom (K.J.F., A.R.); and CIFAR Azrieli Global Scholar, CIFAR, Toronto, Canada (A.R.)
| | - Adeel Razi
- Turner Institute for Brain and Mental Health (D.S., G.F.E., A.R.) and Monash Biomedical Imaging (G.F.E., A.R.), Monash University, Clayton, Victoria, Australia; Wellcome Centre for Human Neuroimaging, UCL, London, United Kingdom (K.J.F., A.R.); and CIFAR Azrieli Global Scholar, CIFAR, Toronto, Canada (A.R.)
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8
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Smausz R, Neill J, Gigg J. Neural mechanisms underlying psilocybin's therapeutic potential - the need for preclinical in vivo electrophysiology. J Psychopharmacol 2022; 36:781-793. [PMID: 35638159 PMCID: PMC9247433 DOI: 10.1177/02698811221092508] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Psilocybin is a naturally occurring psychedelic compound with profound perception-, emotion- and cognition-altering properties and great potential for treating brain disorders. However, the neural mechanisms mediating its effects require in-depth investigation as there is still much to learn about how psychedelic drugs produce their profound and long-lasting effects. In this review, we outline the current understanding of the neurophysiology of psilocybin's psychoactive properties, highlighting the need for additional preclinical studies to determine its effect on neural network dynamics. We first describe how psilocybin's effect on brain regions associated with the default-mode network (DMN), particularly the prefrontal cortex and hippocampus, likely plays a key role in mediating its consciousness-altering properties. We then outline the specific receptor and cell types involved and discuss contradictory evidence from neuroimaging studies regarding psilocybin's net effect on activity within these regions. We go on to argue that in vivo electrophysiology is ideally suited to provide a more holistic, neural network analysis approach to understand psilocybin's mode of action. Thus, we integrate information about the neural bases for oscillatory activity generation with the accumulating evidence about psychedelic drug effects on neural synchrony within DMN-associated areas. This approach will help to generate important questions for future preclinical and clinical studies. Answers to these questions are vital for determining the neural mechanisms mediating psilocybin's psychotherapeutic potential, which promises to improve outcomes for patients with severe depression and other difficulty to treat conditions.
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Affiliation(s)
- Rebecca Smausz
- Division of Neuroscience and
Experimental Psychology, Faculty of Biology, Medicine and Health, The
University of Manchester, Manchester, UK
| | - Joanna Neill
- Division of Pharmacy and
Optometry, Faculty of Biology, Medicine and Health, The University of
Manchester, Manchester, UK,Medical Psychedelics Working
Group, Drug Science, UK
| | - John Gigg
- Division of Neuroscience and
Experimental Psychology, Faculty of Biology, Medicine and Health, The
University of Manchester, Manchester, UK,John Gigg, Division of Neuroscience
and Experimental Psychology, Faculty of Biology, Medicine and Health,
The University of Manchester, Manchester, M13 9PT, 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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10
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James E, Keppler J, L Robertshaw T, Sessa B. N,N-dimethyltryptamine and Amazonian ayahuasca plant medicine. Hum Psychopharmacol 2022; 37:e2835. [PMID: 35175662 PMCID: PMC9286861 DOI: 10.1002/hup.2835] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 01/13/2022] [Accepted: 01/26/2022] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Reports have indicated possible uses of ayahuasca for the treatment of conditions including depression, addictions, post-traumatic stress disorder, anxiety and specific psychoneuroendocrine immune system pathologies. The article assesses potential ayahuasca and N,N-dimethyltryptamine (DMT) integration with contemporary healthcare. The review also seeks to provide a summary of selected literature regarding the mechanisms of action of DMT and ayahuasca; and assess to what extent the state of research can explain reports of unusual phenomenology. DESIGN A narrative review. RESULTS Compounds in ayahuasca have been found to bind to serotonergic receptors, glutaminergic receptors, sigma-1 receptors, trace amine-associated receptors, and modulate BDNF expression and the dopaminergic system. Subjective effects are associated with increased delta and theta oscillations in amygdala and hippocampal regions, decreased alpha wave activity in the default mode network, and stimulations of vision-related brain regions particularly in the visual association cortex. Both biological processes and field of consciousness models have been proposed to explain subjective effects of DMT and ayahuasca, however, the evidence supporting the proposed models is not sufficient to make confident conclusions. Ayahuasca plant medicine and DMT represent potentially novel treatment modalities. CONCLUSIONS Further research is required to clarify the mechanisms of action and develop treatments which can be made available to the general public. Integration between healthcare research institutions and reputable practitioners in the Amazon is recommended.
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Affiliation(s)
- Edward James
- School of Pharmacy and Pharmaceutical SciencesCardiff UniversityCardiffUK
| | | | | | - Ben Sessa
- Centre for NeuropsychopharmacologyDivision of Brain SciencesFaculty of MedicineImperial College LondonLondonUK
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11
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Lovinger DM, Mateo Y, Johnson KA, Engi SA, Antonazzo M, Cheer JF. Local modulation by presynaptic receptors controls neuronal communication and behaviour. Nat Rev Neurosci 2022; 23:191-203. [PMID: 35228740 PMCID: PMC10709822 DOI: 10.1038/s41583-022-00561-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/19/2022] [Indexed: 12/15/2022]
Abstract
Central nervous system neurons communicate via fast synaptic transmission mediated by ligand-gated ion channel (LGIC) receptors and slower neuromodulation mediated by G protein-coupled receptors (GPCRs). These receptors influence many neuronal functions, including presynaptic neurotransmitter release. Presynaptic LGIC and GPCR activation by locally released neurotransmitters influences neuronal communication in ways that modify effects of somatic action potentials. Although much is known about presynaptic receptors and their mechanisms of action, less is known about when and where these receptor actions alter release, especially in vivo. This Review focuses on emerging evidence for important local presynaptic receptor actions and ideas for future studies in this area.
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Affiliation(s)
- David M Lovinger
- Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, USA.
| | - Yolanda Mateo
- Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, USA
| | - Kari A Johnson
- Department of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Sheila A Engi
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Mario Antonazzo
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Joseph F Cheer
- Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
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12
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Thomas CW, Blanco-Duque C, Bréant BJ, Goodwin GM, Sharp T, Bannerman DM, Vyazovskiy VV. Psilocin acutely alters sleep-wake architecture and cortical brain activity in laboratory mice. Transl Psychiatry 2022; 12:77. [PMID: 35197453 PMCID: PMC8866416 DOI: 10.1038/s41398-022-01846-9] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 02/02/2022] [Accepted: 02/03/2022] [Indexed: 01/03/2023] Open
Abstract
Serotonergic psychedelic drugs, such as psilocin (4-hydroxy-N,N-dimethyltryptamine), profoundly alter the quality of consciousness through mechanisms which are incompletely understood. Growing evidence suggests that a single psychedelic experience can positively impact long-term psychological well-being, with relevance for the treatment of psychiatric disorders, including depression. A prominent factor associated with psychiatric disorders is disturbed sleep, and the sleep-wake cycle is implicated in the homeostatic regulation of neuronal activity and synaptic plasticity. However, it remains largely unknown to what extent psychedelic agents directly affect sleep, in terms of both acute arousal and homeostatic sleep regulation. Here, chronic electrophysiological recordings were obtained in mice to track sleep-wake architecture and cortical activity after psilocin injection. Administration of psilocin led to delayed REM sleep onset and reduced NREM sleep maintenance for up to approximately 3 h after dosing, and the acute EEG response was associated primarily with an enhanced oscillation around 4 Hz. No long-term changes in sleep-wake quantity were found. When combined with sleep deprivation, psilocin did not alter the dynamics of homeostatic sleep rebound during the subsequent recovery period, as reflected in both sleep amount and EEG slow-wave activity. However, psilocin decreased the recovery rate of sleep slow-wave activity following sleep deprivation in the local field potentials of electrodes targeting the medial prefrontal and surrounding cortex. It is concluded that psilocin affects both global vigilance state control and local sleep homeostasis, an effect which may be relevant for its antidepressant efficacy.
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Affiliation(s)
- Christopher W. Thomas
- grid.4991.50000 0004 1936 8948Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Cristina Blanco-Duque
- grid.4991.50000 0004 1936 8948Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Benjamin J. Bréant
- grid.4991.50000 0004 1936 8948Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Guy M. Goodwin
- grid.4991.50000 0004 1936 8948Department of Psychiatry, University of Oxford, Oxford, UK
| | - Trevor Sharp
- grid.4991.50000 0004 1936 8948Department of Pharmacology, University of Oxford, Oxford, UK
| | - David M. Bannerman
- grid.4991.50000 0004 1936 8948Department of Experimental Psychology, University of Oxford, Oxford, UK
| | - Vladyslav V. Vyazovskiy
- grid.4991.50000 0004 1936 8948Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
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13
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Vollenweider FX, Smallridge JW. Classic Psychedelic Drugs: Update on Biological
Mechanisms. PHARMACOPSYCHIATRY 2022; 55:121-138. [PMID: 35079988 PMCID: PMC9110100 DOI: 10.1055/a-1721-2914] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Renewed interest in the effects of psychedelics in the treatment of psychiatric
disorders warrants a better understanding of the neurobiological mechanisms
underlying the effects of these substances. During the past two decades,
state-of-the-art studies of animals and humans have yielded new important
insights into the molecular, cellular, and systems-level actions of psychedelic
drugs. These efforts have revealed that psychedelics affect primarily
serotonergic receptor subtypes located in cortico-thalamic and cortico-cortical
feedback circuits of information processing. Psychedelic drugs modulate
excitatory-inhibitory balance in these circuits and can participate in
neuroplasticity within brain structures critical for the integration of
information relevant to sensation, cognition, emotions, and the narrative of
self. Neuroimaging studies showed that characteristic dimensions of the
psychedelic experience obtained through subjective questionnaires as well as
alterations in self-referential processing and emotion regulation obtained
through neuropsychological tasks are associated with distinct changes in brain
activity and connectivity patterns at multiple-system levels. These recent
results suggest that changes in self-experience, emotional processing, and
social cognition may contribute to the potential therapeutic effects of
psychedelics.
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Affiliation(s)
- Franz X. Vollenweider
- Neuropsychopharmacology and Brain Imaging, Department of Psychiatry,
Psychotherapy and Psychosomatics, University Hospital for Psychiatry Zurich,
Zurich, Switzerland
| | - John W. Smallridge
- Neuropsychopharmacology and Brain Imaging, Department of Psychiatry,
Psychotherapy and Psychosomatics, University Hospital for Psychiatry Zurich,
Zurich, Switzerland
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14
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Desouza LA, Benekareddy M, Fanibunda SE, Mohammad F, Janakiraman B, Ghai U, Gur T, Blendy JA, Vaidya VA. The Hallucinogenic Serotonin 2A Receptor Agonist, 2,5-Dimethoxy-4-Iodoamphetamine, Promotes cAMP Response Element Binding Protein-Dependent Gene Expression of Specific Plasticity-Associated Genes in the Rodent Neocortex. Front Mol Neurosci 2022; 14:790213. [PMID: 35002622 PMCID: PMC8739224 DOI: 10.3389/fnmol.2021.790213] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 11/26/2021] [Indexed: 12/27/2022] Open
Abstract
Psychedelic compounds that target the 5-HT2A receptor are reported to evoke psychoplastogenic effects, including enhanced dendritic arborization and synaptogenesis. Transcriptional regulation of neuronal plasticity-associated genes is implicated in the cytoarchitectural effects of serotonergic psychedelics, however, the transcription factors that drive this regulation are poorly elucidated. Here, we addressed the contribution of the transcription factor cyclic adenosine monophosphate (cAMP)-response element binding protein (CREB) in the regulation of neuronal plasticity-associated genes by the hallucinogenic 5-HT2A receptor agonist, 2,5-dimethoxy-4-iodoamphetamine (DOI). In vitro studies with rat cortical neurons indicated that DOI enhances the phosphorylation of CREB (pCREB) through mitogen-activated protein (MAP) kinase and calcium/calmodulin dependent kinase II (CaMKII) pathways, with both cascades contributing to the DOI-evoked upregulation of Arc, Bdnf1, Cebpb, and Egr2 expression, whilst the upregulation of Egr1 and cFos mRNA involved the MAP kinase and CaMKII pathway respectively. We observed a robust DOI-evoked increase in the expression of several neuronal plasticity-associated genes in the rat neocortex in vivo. This DOI-evoked upregulation of neuronal plasticity-associated genes was completely blocked by the 5-HT2A receptor antagonist MDL100,907 in vitro and was also abrogated in the neocortex of 5-HT2A receptor deficient mice. Further, 5-HT2A receptor stimulation enhanced pCREB enrichment at putative cAMP response element (CRE) binding sites in the Arc, Bdnf1, Cebpb, cFos, but not Egr1 and Egr2, promoters in the rodent neocortex. The DOI-mediated transcriptional induction of Arc, cFos and Cebpb was significantly attenuated in the neocortex of CREB deficient/knockout (CREBαδ KO) mice. Collectively, these results indicate that the hallucinogenic 5-HT2A receptor agonist DOI leads to a rapid transcriptional upregulation of several neuronal plasticity-associated genes, with a subset of them exhibiting a CREB-dependent regulation. Our findings raise the intriguing possibility that similar to slow-acting classical antidepressants, rapid-action serotonergic psychedelics that target the 5-HT2A receptor may also recruit the transcription factor CREB to enhance the expression of neuronal plasticity-associated genes in the neocortex, which could in turn contribute to the rapid psychoplastogenic changes evoked by these compounds.
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Affiliation(s)
- Lynette A Desouza
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Madhurima Benekareddy
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Sashaina E Fanibunda
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India.,Medical Research Centre, Kasturba Health Society, Mumbai, India
| | - Farhan Mohammad
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Balaganesh Janakiraman
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Utkarsha Ghai
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Tamar Gur
- Department of Psychiatry and Behavioral Health, The Ohio State University College of Medicine, Columbus, OH, United States
| | - Julie A Blendy
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Vidita A Vaidya
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
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15
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Bachmann T. Representational 'touch' and modulatory 'retouch'-two necessary neurobiological processes in thalamocortical interaction for conscious experience. Neurosci Conscious 2021; 2021:niab045. [PMID: 34925911 PMCID: PMC8672242 DOI: 10.1093/nc/niab045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 11/16/2021] [Accepted: 11/30/2021] [Indexed: 12/01/2022] Open
Abstract
Theories of consciousness using neurobiological data or being influenced by these data have been focused either on states of consciousness or contents of consciousness. These theories have occasionally used evidence from psychophysical phenomena where conscious experience is a dependent experimental variable. However, systematic catalog of many such relevant phenomena has not been offered in terms of these theories. In the perceptual retouch theory of thalamocortical interaction, recently developed to become a blend with the dendritic integration theory, consciousness states and contents of consciousness are explained by the same mechanism. This general-purpose mechanism has modulation of the cortical layer-5 pyramidal neurons that represent contents of consciousness as its core. As a surplus, many experimental psychophysical phenomena of conscious perception can be explained by the workings of this mechanism. Historical origins and current views inherent in this theory are presented and reviewed.
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Affiliation(s)
- Talis Bachmann
- Department of Penal Law, Laboratory of Cognitive Neuroscience, School of Law, University of Tartu (Tallinn Branch), Kaarli puiestee 3, Tallinn 10119, Estonia
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16
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Jones GH, Vecera CM, Pinjari OF, Machado-Vieira R. Inflammatory signaling mechanisms in bipolar disorder. J Biomed Sci 2021; 28:45. [PMID: 34112182 PMCID: PMC8194019 DOI: 10.1186/s12929-021-00742-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 06/08/2021] [Indexed: 12/12/2022] Open
Abstract
Bipolar disorder is a decidedly heterogeneous and multifactorial disease, with a high individual and societal burden. While not all patients display overt markers of elevated inflammation, significant evidence suggests that aberrant immune signaling contributes to all stages of the disease, and likely explains the elevated rates of comorbid inflammatory illnesses seen in this population. While individual systems have been intensely studied and targeted, a relative paucity of attention has been given to the interconnecting role of inflammatory signals therein. This review presents an updated overview of some of the most prominent pathophysiologic mechanisms in bipolar disorder, from mitochondrial, endoplasmic reticular, and calcium homeostasis, to purinergic, kynurenic, and hormonal/neurotransmitter signaling, showing inflammation to act as a powerful nexus between these systems. Several areas with a high degree of mechanistic convergence within this paradigm are highlighted to present promising future targets for therapeutic development and screening.
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Affiliation(s)
- Gregory H Jones
- Department of Psychiatry and Behavioral Sciences, University of Texas Health Science Center at Houston (UTHealth), 1941 East Road, Houston, TX, 77054, USA.
| | - Courtney M Vecera
- Department of Psychiatry and Behavioral Sciences, University of Texas Health Science Center at Houston (UTHealth), 1941 East Road, Houston, TX, 77054, USA
| | - Omar F Pinjari
- Department of Psychiatry and Behavioral Sciences, University of Texas Health Science Center at Houston (UTHealth), 1941 East Road, Houston, TX, 77054, USA
| | - Rodrigo Machado-Vieira
- Department of Psychiatry and Behavioral Sciences, University of Texas Health Science Center at Houston (UTHealth), 1941 East Road, Houston, TX, 77054, USA
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17
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Psychedelic Medicines in Major Depression: Progress and Future Challenges. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1305:515-533. [PMID: 33834416 DOI: 10.1007/978-981-33-6044-0_26] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The volume of research on the therapeutic use of psychedelic drugs has been increasing during the last decades. Partly because of the need of innovative treatments in psychiatry, several studies have assessed the safety and efficacy of drugs like psilocybin or ayahuasca for a wide range of mental disorders, including major depression. The first section of this chapter will offer an introduction to psychedelic research, including a brief historical overview and discussions about appropriate terminology. In the second section, the recently published clinical trials in which psychedelic drugs were administered to patients will be analysed in detail. Then, in the third section, the main neurobiological mechanisms of these drugs will be described, noting that while some of these mechanisms could be potentially associated with their therapeutic properties, they are commonly used as adjuvants in psychotherapeutic processes. The last section suggests future challenges for this groundbreaking field of research and therapy.
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18
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Xiang Z, Lv X, Lin X, O'Brien DE, Altman MK, Lindsley CW, Javitch JA, Niswender CM, Conn PJ. Input-specific regulation of glutamatergic synaptic transmission in the medial prefrontal cortex by mGlu 2/mGlu 4 receptor heterodimers. Sci Signal 2021; 14:14/677/eabd2319. [PMID: 33824180 DOI: 10.1126/scisignal.abd2319] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Metabotropic glutamate receptors (mGluRs) are G protein-coupled receptors that regulate various aspects of central nervous system processing in normal physiology and in disease. They are thought to function as disulfide-linked homodimers, but studies have suggested that mGluRs can form functional heterodimers in cell lines. Using selective allosteric ligands, ex vivo brain slice electrophysiology, and optogenetic approaches, we found that two mGluR subtypes-mGluR2 and mGluR4 (or mGlu2 and mGlu4)-exist as functional heterodimers that regulate excitatory transmission in a synapse-specific manner within the rodent medial prefrontal cortex (mPFC). Activation of mGlu2/mGlu4 heterodimers inhibited glutamatergic signaling at thalamo-mPFC synapses but not at hippocampus-mPFC or amygdala-mPFC synapses. These findings raise the possibility that selectively targeting these heterodimers could be a therapeutic strategy for some neurologic and neuropsychiatric disorders involving specific brain circuits.
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Affiliation(s)
- Zixiu Xiang
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA.,Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA
| | - Xiaohui Lv
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA.,Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA
| | - Xin Lin
- Department of Psychiatry, Columbia University, New York, NY 10032, USA.,Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA
| | - Daniel E O'Brien
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA.,Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA
| | - Molly K Altman
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA.,Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA
| | - Craig W Lindsley
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA.,Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA.,Department of Chemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Jonathan A Javitch
- Department of Psychiatry, Columbia University, New York, NY 10032, USA.,Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA.,Department of Molecular Pharmacology and Therapeutics, Columbia University, New York, NY 10032, USA
| | - Colleen M Niswender
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA.,Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA.,Vanderbilt Kennedy Center, Vanderbilt University, Nashville, TN 37232, USA
| | - P Jeffrey Conn
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA. .,Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA.,Vanderbilt Kennedy Center, Vanderbilt University, Nashville, TN 37232, USA
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19
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Dos Santos RG, Hallak JE, Baker G, Dursun S. Hallucinogenic/psychedelic 5HT2A receptor agonists as rapid antidepressant therapeutics: Evidence and mechanisms of action. J Psychopharmacol 2021; 35:453-458. [PMID: 33740877 DOI: 10.1177/0269881120986422] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Major depressive disorder (MDD) is among the most prevalent mental health disorders worldwide, and it is associated with a reduced quality of life and enormous costs to health care systems. Available drug treatments show low-to-moderate response in most patients, with almost a third of patients being non-responders (treatment-resistant). Furthermore, most currently available medications need several weeks to achieve therapeutic effects, and the long-term use of these drugs is often associated with significant unwanted side effects and resultant reductions in treatment compliance. Therefore, more effective, safer, and faster-acting antidepressants with enduring effects are needed. Together with ketamine, psychedelics (or classic or serotoninergic hallucinogens) such as lysergic acid diethylamide (LSD), psilocybin, and ayahuasca are among the few compounds with recent human evidence of fast-acting antidepressant effects. Several studies in the 1950s to 1970s reported antidepressive and anxiolytic effects of these drugs, which are being confirmed by modern trials (LSD, one trial; psilocybin, five trials; ayahuasca, two trials). The effects of these drugs appear to be produced primarily by their agonism at serotonin (5-hydroxytryptamine, 5-HT) receptors, especially the 5-HT2A receptor. Considering the overall burden of MDD and the necessity of new therapeutic options, the promising (but currently limited) evidence of safety and efficacy of psychedelics has encouraged the scientific community to explore more fully their beneficial effects in MDD.
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Affiliation(s)
- Rafael Guimarães Dos Santos
- Department of Neurosciences and Behavior, Ribeirão Preto Medical School, University of São Paulo, SP, Brazil.,National Institute for Translational Medicine (INCT-TM), CNPq, Brazil
| | - Jaime Ec Hallak
- Department of Neurosciences and Behavior, Ribeirão Preto Medical School, University of São Paulo, SP, Brazil.,National Institute for Translational Medicine (INCT-TM), CNPq, Brazil.,Department of Psychiatry (Neurochemical Research Unit) and Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | - Glen Baker
- National Institute for Translational Medicine (INCT-TM), CNPq, Brazil.,Department of Psychiatry (Neurochemical Research Unit) and Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | - Serdar Dursun
- National Institute for Translational Medicine (INCT-TM), CNPq, Brazil.,Department of Psychiatry (Neurochemical Research Unit) and Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
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20
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dos Santos RG, Bouso JC, Rocha JM, Rossi GN, Hallak JE. The Use of Classic Hallucinogens/Psychedelics in a Therapeutic Context: Healthcare Policy Opportunities and Challenges. Risk Manag Healthc Policy 2021; 14:901-910. [PMID: 33707976 PMCID: PMC7943545 DOI: 10.2147/rmhp.s300656] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 02/24/2021] [Indexed: 01/23/2023] Open
Abstract
Psychedelics or serotonergic hallucinogens are a group of substances that share the agonism of serotonergic 5-HT2A receptors as their main mechanism of action. Its main effects include changes in perception, cognitive process, and mood. Despite being used for centuries by different cultures in ritual contexts, these substances have currently aroused the interest of science and industry for their promising antidepressant, anxiolytic, and anti-addictive effects. Considering this evidence, this article aims to explore some of the possible health policy challenges to integrate these therapeutic tools into broad and heterogeneous health systems. As a main benefit, these substances produce rapid and enduring effects with the administration of single or few doses, which could lead to new treatment possibilities for patients with severe mental disorders resistant to the usual medications. The main challenge is associated with the fact that these substances remain scheduled in most countries and are associated with social stigma related to their recreational use (especially LSD and psilocybin). This situation makes it exceedingly difficult to conduct clinical trials, although international conventions allow such research. Ethically, this could be interpreted as a violation of human rights since thousands of people are prevented from having access to possible benefits. Interestingly, ritual ayahuasca use is more acceptable to the public than the use of psilocybin-containing mushrooms or LSD. The controlled, clinical use of LSD and psilocybin seems to be less criticized and is being explored by the industry. Rigorous scientific evidence coupled with industrial interests (LSD and psilocybin), together with respect for traditional uses (ayahuasca) and international conventions, seems to be the best way for these drugs to be integrated into health systems in the next years. Which highlights the need for an urgent dialogue between science, health system, society, and politics.
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Affiliation(s)
- Rafael Guimarães dos Santos
- Department of Neurosciences and Behavior, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
- National Institute of Science and Technology – Translational Medicine, Ribeirão Preto, Brazil
- ICEERS Foundation, International Center for Ethnobotanical Education, Research and Services, Barcelona, Spain
| | - José Carlos Bouso
- Department of Neurosciences and Behavior, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
- ICEERS Foundation, International Center for Ethnobotanical Education, Research and Services, Barcelona, Spain
- Medical Anthropology Research Center, Universitat Rovira i Virgili, Tarragona, Spain
| | - Juliana Mendes Rocha
- Department of Neurosciences and Behavior, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Giordano Novak Rossi
- Department of Neurosciences and Behavior, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Jaime E Hallak
- Department of Neurosciences and Behavior, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
- National Institute of Science and Technology – Translational Medicine, Ribeirão Preto, Brazil
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21
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Kadriu B, Greenwald M, Henter ID, Gilbert JR, Kraus C, Park LT, Zarate CA. Ketamine and Serotonergic Psychedelics: Common Mechanisms Underlying the Effects of Rapid-Acting Antidepressants. Int J Neuropsychopharmacol 2021; 24:8-21. [PMID: 33252694 PMCID: PMC7816692 DOI: 10.1093/ijnp/pyaa087] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 10/13/2020] [Accepted: 11/16/2020] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND The glutamatergic modulator ketamine has created a blueprint for studying novel pharmaceuticals in the field. Recent studies suggest that "classic" serotonergic psychedelics (SPs) may also have antidepressant efficacy. Both ketamine and SPs appear to produce rapid, sustained antidepressant effects after a transient psychoactive period. METHODS This review summarizes areas of overlap between SP and ketamine research and considers the possibility of a common, downstream mechanism of action. The therapeutic relevance of the psychoactive state, overlapping cellular and molecular effects, and overlapping electrophysiological and neuroimaging observations are all reviewed. RESULTS Taken together, the evidence suggests a potentially shared mechanism wherein both ketamine and SPs may engender rapid neuroplastic effects in a glutamatergic activity-dependent manner. It is postulated that, though distinct, both ketamine and SPs appear to produce acute alterations in cortical network activity that may initially produce psychoactive effects and later produce milder, sustained changes in network efficiency associated with therapeutic response. However, despite some commonalities between the psychoactive component of these pharmacologically distinct therapies-such as engagement of the downstream glutamatergic pathway-the connection between psychoactive impact and antidepressant efficacy remains unclear and requires more rigorous research. CONCLUSIONS Rapid-acting antidepressants currently under investigation may share some downstream pharmacological effects, suggesting that their antidepressant effects may come about via related mechanisms. Given the prototypic nature of ketamine research and recent progress in this area, this platform could be used to investigate entirely new classes of antidepressants with rapid and robust actions.
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Affiliation(s)
- Bashkim Kadriu
- Section on the Neurobiology and Treatment of Mood Disorders, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Maximillian Greenwald
- Section on the Neurobiology and Treatment of Mood Disorders, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Ioline D Henter
- Section on the Neurobiology and Treatment of Mood Disorders, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Jessica R Gilbert
- Section on the Neurobiology and Treatment of Mood Disorders, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Christoph Kraus
- Section on the Neurobiology and Treatment of Mood Disorders, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Lawrence T Park
- Section on the Neurobiology and Treatment of Mood Disorders, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Carlos A Zarate
- Section on the Neurobiology and Treatment of Mood Disorders, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
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22
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Cortical influences of serotonin and glutamate on layer V pyramidal neurons. PROGRESS IN BRAIN RESEARCH 2021; 261:341-378. [PMID: 33785135 DOI: 10.1016/bs.pbr.2020.11.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Layer V pyramidal neurons constitute principle output neurons of the medial prefrontal cortex (mPFC)/neocortex to subcortical regions including the intralaminar/midline thalamic nuclei, amygdala, basal ganglia, brainstem nuclei and the spinal cord. The effects of 5-hydroxytryptamine (5-HT) on layer V pyramidal cells primarily reflect a range of excitatory influences through 5-HT2A receptors and inhibitory influences through non-5-HT2A receptors, including 5-HT1A receptors. While the 5-HT2A receptor is primarily a postsynaptic receptor on throughout the apical dendritic field of 5-HT2A receptors, activation of a minority of 5-HT2A receptors also appears to increase spontaneous excitatory postsynaptic currents/potentials (EPSCs/EPSPs) via a presynaptic effect on thalamocortical terminals arising from the midline and intralaminar thalamic nuclei. Activation of 5-HT2A receptors by the phenethylamine hallucinogen also appears to increase asynchronous release of glutamate upon the layer V pyramidal dendritic field, an effect that is suppressed by 5-HT itself through non-5-HT2A receptors. Serotonergic hallucinogens acting on 5-HT2A receptors also appears to increase gene expression of immediate early genes (iEG) and other receptors appearing to induce an iEG-like response like BDNF. Psychedelic hallucinogens acting on 5-HT2A receptors also induce head twitches in rodents that appear related to induction of glutamate release. These electrophysiological, biochemical and behavioral effects of serotonergic hallucinogens appear to be related to modulating glutamatergic thalamocortical neurotransmission and/or shifting the balance toward 5-HT2A receptor activation and away from non-5-HT2A receptor activation. These 5-HT2A receptor induced responses are modulated by feedback homeostatic mechanisms through mGlu2, mGlu4, and mGlu8 presynaptic receptors on thalamocortical terminals. These 5-HT2A receptor and glutamatergic interactions also appear to play a role on higher cortical functions of the mPFC such as motoric impulsivity and antidepressant-like behavioral responses on the differential-reinforcement-of low rate 72-s (DRL 72-s schedule). These mutually opposing effects between 5-HT2A receptor and mGlu autoreceptor activation (e.g., blocking 5-HT2A receptors and enhancing activity at mGlu2 receptors) may play a clinical role with respect to currently prescribed or novel antidepressant drugs. Thus, there is an important balance between 5-HT2A receptor activation and activation of mGlu autoreceptors on prefrontal cortical layer V pyramidal cells with respect to the electrophysiological, biochemical and behavioral effects serotonergic hallucinogenic drugs.
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23
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Avram M, Rogg H, Korda A, Andreou C, Müller F, Borgwardt S. Bridging the Gap? Altered Thalamocortical Connectivity in Psychotic and Psychedelic States. Front Psychiatry 2021; 12:706017. [PMID: 34721097 PMCID: PMC8548726 DOI: 10.3389/fpsyt.2021.706017] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 09/16/2021] [Indexed: 12/23/2022] Open
Abstract
Psychiatry has a well-established tradition of comparing drug-induced experiences to psychotic symptoms, based on shared phenomena such as altered perceptions. The present review focuses on experiences induced by classic psychedelics, which are substances capable of eliciting powerful psychoactive effects, characterized by distortions/alterations of several neurocognitive processes (e.g., hallucinations). Herein we refer to such experiences as psychedelic states. Psychosis is a clinical syndrome defined by impaired reality testing, also characterized by impaired neurocognitive processes (e.g., hallucinations and delusions). In this review we refer to acute phases of psychotic disorders as psychotic states. Neuropharmacological investigations have begun to characterize the neurobiological mechanisms underpinning the shared and distinct neurophysiological changes observed in psychedelic and psychotic states. Mounting evidence indicates changes in thalamic filtering, along with disturbances in cortico-striato-pallido-thalamo-cortical (CSPTC)-circuitry, in both altered states. Notably, alterations in thalamocortical functional connectivity were reported by functional magnetic resonance imaging (fMRI) studies. Thalamocortical dysconnectivity and its clinical relevance are well-characterized in psychotic states, particularly in schizophrenia research. Specifically, studies report hyperconnectivity between the thalamus and sensorimotor cortices and hypoconnectivity between the thalamus and prefrontal cortices, associated with patients' psychotic symptoms and cognitive disturbances, respectively. Intriguingly, studies also report hyperconnectivity between the thalamus and sensorimotor cortices in psychedelic states, correlating with altered visual and auditory perceptions. Taken together, the two altered states appear to share clinically and functionally relevant dysconnectivity patterns. In this review we discuss recent findings of thalamocortical dysconnectivity, its putative extension to CSPTC circuitry, along with its clinical implications and future directions.
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Affiliation(s)
- Mihai Avram
- Department of Psychiatry and Psychotherapy, Schleswig Holstein University Hospital, University of Lübeck, Lübeck, Germany
| | - Helena Rogg
- Department of Psychiatry and Psychotherapy, Schleswig Holstein University Hospital, University of Lübeck, Lübeck, Germany
| | - Alexandra Korda
- Department of Psychiatry and Psychotherapy, Schleswig Holstein University Hospital, University of Lübeck, Lübeck, Germany
| | - Christina Andreou
- Department of Psychiatry and Psychotherapy, Schleswig Holstein University Hospital, University of Lübeck, Lübeck, Germany
| | - Felix Müller
- Department of Psychiatry (UPK), University of Basel, Basel, Switzerland
| | - Stefan Borgwardt
- Department of Psychiatry and Psychotherapy, Schleswig Holstein University Hospital, University of Lübeck, Lübeck, Germany
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24
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Inserra A, De Gregorio D, Gobbi G. Psychedelics in Psychiatry: Neuroplastic, Immunomodulatory, and Neurotransmitter Mechanisms. Pharmacol Rev 2020; 73:202-277. [PMID: 33328244 DOI: 10.1124/pharmrev.120.000056] [Citation(s) in RCA: 93] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Mounting evidence suggests safety and efficacy of psychedelic compounds as potential novel therapeutics in psychiatry. Ketamine has been approved by the Food and Drug Administration in a new class of antidepressants, and 3,4-methylenedioxymethamphetamine (MDMA) is undergoing phase III clinical trials for post-traumatic stress disorder. Psilocybin and lysergic acid diethylamide (LSD) are being investigated in several phase II and phase I clinical trials. Hence, the concept of psychedelics as therapeutics may be incorporated into modern society. Here, we discuss the main known neurobiological therapeutic mechanisms of psychedelics, which are thought to be mediated by the effects of these compounds on the serotonergic (via 5-HT2A and 5-HT1A receptors) and glutamatergic [via N-methyl-d-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors] systems. We focus on 1) neuroplasticity mediated by the modulation of mammalian target of rapamycin-, brain-derived neurotrophic factor-, and early growth response-related pathways; 2) immunomodulation via effects on the hypothalamic-pituitary-adrenal axis, nuclear factor ĸB, and cytokines such as tumor necrosis factor-α and interleukin 1, 6, and 10 production and release; and 3) modulation of serotonergic, dopaminergic, glutamatergic, GABAergic, and norepinephrinergic receptors, transporters, and turnover systems. We discuss arising concerns and ways to assess potential neurobiological changes, dependence, and immunosuppression. Although larger cohorts are required to corroborate preliminary findings, the results obtained so far are promising and represent a critical opportunity for improvement of pharmacotherapies in psychiatry, an area that has seen limited therapeutic advancement in the last 20 years. Studies are underway that are trying to decouple the psychedelic effects from the therapeutic effects of these compounds. SIGNIFICANCE STATEMENT: Psychedelic compounds are emerging as potential novel therapeutics in psychiatry. However, understanding of molecular mechanisms mediating improvement remains limited. This paper reviews the available evidence concerning the effects of psychedelic compounds on pathways that modulate neuroplasticity, immunity, and neurotransmitter systems. This work aims to be a reference for psychiatrists who may soon be faced with the possibility of prescribing psychedelic compounds as medications, helping them assess which compound(s) and regimen could be most useful for decreasing specific psychiatric symptoms.
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Affiliation(s)
- Antonio Inserra
- Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University, Montreal, Quebec, Canada
| | - Danilo De Gregorio
- Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University, Montreal, Quebec, Canada
| | - Gabriella Gobbi
- Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University, Montreal, Quebec, Canada
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25
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Psychedelic drugs: neurobiology and potential for treatment of psychiatric disorders. Nat Rev Neurosci 2020; 21:611-624. [PMID: 32929261 DOI: 10.1038/s41583-020-0367-2] [Citation(s) in RCA: 182] [Impact Index Per Article: 45.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/07/2020] [Indexed: 12/13/2022]
Abstract
Renewed interest in the use of psychedelics in the treatment of psychiatric disorders warrants a better understanding of the neurobiological mechanisms underlying the effects of these substances. After a hiatus of about 50 years, state-of-the art studies have recently begun to close important knowledge gaps by elucidating the mechanisms of action of psychedelics with regard to their effects on receptor subsystems, systems-level brain activity and connectivity, and cognitive and emotional processing. In addition, functional studies have shown that changes in self-experience, emotional processing and social cognition may contribute to the potential therapeutic effects of psychedelics. These discoveries provide a scientific road map for the investigation and application of psychedelic substances in psychiatry.
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26
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Buchborn T, Lyons T, Song C, Feilding A, Knöpfel T. The serotonin 2A receptor agonist 25CN-NBOH increases murine heart rate and neck-arterial blood flow in a temperature-dependent manner. J Psychopharmacol 2020; 34:786-794. [PMID: 32048564 PMCID: PMC7488829 DOI: 10.1177/0269881120903465] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND Serotonin 2A receptors, the molecular target of psychedelics, are expressed by neuronal and vascular cells, both of which might contribute to brain haemodynamic characteristics for the psychedelic state. AIM Aiming for a systemic understanding of psychedelic vasoactivity, here we investigated the effect of N-(2-hydroxybenzyl)-2,5-dimethoxy-4-cyanophenylethylamine - a new-generation agonist with superior serotonin 2A receptor selectivity - on brain-supplying neck-arterial blood flow. METHODS We recorded core body temperature and employed non-invasive, collar-sensor based pulse oximetry in anesthetised mice to extract parameters of local blood perfusion, oxygen saturation, heart and respiration rate. Hypothesising an overlap between serotonergic pulse- and thermoregulation, recordings were done under physiological and elevated pad temperatures. RESULTS N-(2-hydroxybenzyl)-2,5-dimethoxy-4-cyanophenylethylamine (1.5 mg/kg, subcutaneous) significantly increased the frequency of heart beats accompanied by a slight elevation of neck-arterial blood flow. Increasing the animal-supporting heat-pad temperature from 37°C to 41°C enhanced the drug's effect on blood flow while counteracting tachycardia. Additionally, N-(2-hydroxybenzyl)-2,5-dimethoxy-4-cyanophenylethylamine promoted bradypnea, which, like tachycardia, quickly reversed at the elevated pad temperature. The interrelatedness of N-(2-hydroxybenzyl)-2,5-dimethoxy-4-cyanophenylethylamine's respiro-cardiovascular effects and thermoregulation was further corroborated by the drug selectively increasing the core body temperature at the elevated pad temperature. Arterial oxygen saturation was not affected by N-(2-hydroxybenzyl)-2,5-dimethoxy-4-cyanophenylethylamine at either temperature. CONCLUSIONS Our findings imply that selective serotonin 2A receptor activation modulates systemic cardiovascular functioning in orchestration with thermoregulation and with immediate relevance to brain-imminent neck (most likely carotid) arteries. As carotid branching is a critical last hub to channel cardiovascular output to or away from the brain, our results might have implications for the brain haemodynamics associated with psychedelia.
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Affiliation(s)
- Tobias Buchborn
- Laboratory for Neuronal Circuit Dynamics, Department of Medicine, Imperial College, London, UK,Centre for Psychedelic Research, Department of Medicine, Imperial College, London, UK,Tobias Buchborn, Laboratory for Neuronal Circuit Dynamics, Department of Medicine, Imperial College, Du Cane Road, Burlington Danes, London, W12 0NN, UK.
| | - Taylor Lyons
- Laboratory for Neuronal Circuit Dynamics, Department of Medicine, Imperial College, London, UK,Centre for Psychedelic Research, Department of Medicine, Imperial College, London, UK
| | - Chenchen Song
- Laboratory for Neuronal Circuit Dynamics, Department of Medicine, Imperial College, London, UK
| | | | - Thomas Knöpfel
- Laboratory for Neuronal Circuit Dynamics, Department of Medicine, Imperial College, London, UK,Centre for Neurotechnology, Institute of Biomedical Engineering, Imperial College, London, UK
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27
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Ulivieri M, Wierońska JM, Lionetto L, Martinello K, Cieslik P, Chocyk A, Curto M, Di Menna L, Iacovelli L, Traficante A, Liberatore F, Mascio G, Antenucci N, Giannino G, Vergassola M, Pittaluga A, Bruno V, Battaglia G, Fucile S, Simmaco M, Nicoletti F, Pilc A, Fazio F. The Trace Kynurenine, Cinnabarinic Acid, Displays Potent Antipsychotic-Like Activity in Mice and Its Levels Are Reduced in the Prefrontal Cortex of Individuals Affected by Schizophrenia. Schizophr Bull 2020; 46:1471-1481. [PMID: 32506121 PMCID: PMC7846105 DOI: 10.1093/schbul/sbaa074] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Cinnabarinic acid (CA) is a kynurenine metabolite that activates mGlu4 metabotropic glutamate receptors. Using a highly sensitive ultra-performance liquid chromatography/tandem mass spectrometry (UPLC/MS-MS) method, we found that CA is present in trace amounts in human brain tissue. CA levels were largely reduced in the prefrontal cortex (PFC) of individuals affected by schizophrenia. This reduction did not correlate with age, sex, duration of the disease, and duration and type of antipsychotic medication and might, therefore, represent a trait of schizophrenia. Interestingly, systemic treatment with low doses of CA (<1 mg/kg, i.p.) showed robust efficacy in several behavioral tests useful to study antipsychotic-like activity in mice and rats and attenuated MK-801-evoked glutamate release. CA failed to display antipsychotic-like activity and inhibit excitatory synaptic transmission in mice lacking mGlu4 receptors. These findings suggest that CA is a potent endogenous antipsychotic-like molecule and reduced CA levels in the PFC might contribute to the pathophysiology of schizophrenia.
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Affiliation(s)
| | | | - Luana Lionetto
- Department of Medical-Surgical Sciences and Translational Medicine, DiMA (Advanced Molecular Diagnosis), Sant’Andrea Hospital—Sapienza University, Rome, Italy
| | | | - Paulina Cieslik
- Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
| | - Agnieszka Chocyk
- Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
| | - Martina Curto
- Department of Neurology and Psychiatry, Sapienza University, Rome, Italy,Department of Clinical and Molecular Medicine, Sapienza University, Rome, Italy,Bipolar & Psychotic Disorders Program, McLean Hospital, Belmont, MA
| | | | - Luisa Iacovelli
- Department of Physiology and Pharmacology, Sapienza University, Rome, Italy
| | | | | | | | - Nico Antenucci
- Department of Physiology and Pharmacology, Sapienza University, Rome, Italy
| | - Giuseppe Giannino
- School of Medicine and Psychology NESMOS Department, Sant’Andrea Hospital, Sapienza University, Rome, Italy
| | | | - Anna Pittaluga
- Department of Pharmacy, DiFAR, University of Genoa, Genoa, Italy,I.R.C.C.S. San Martino Hospital, Genoa, Italy
| | - Valeria Bruno
- I.R.C.C.S. Neuromed, Pozzilli, Italy,Department of Physiology and Pharmacology, Sapienza University, Rome, Italy
| | - Giuseppe Battaglia
- I.R.C.C.S. Neuromed, Pozzilli, Italy,Department of Physiology and Pharmacology, Sapienza University, Rome, Italy
| | - Sergio Fucile
- I.R.C.C.S. Neuromed, Pozzilli, Italy,Department of Physiology and Pharmacology, Sapienza University, Rome, Italy
| | - Maurizio Simmaco
- Department of Medical-Surgical Sciences and Translational Medicine, DiMA (Advanced Molecular Diagnosis), Sant’Andrea Hospital—Sapienza University, Rome, Italy
| | - Ferdinando Nicoletti
- I.R.C.C.S. Neuromed, Pozzilli, Italy,Department of Physiology and Pharmacology, Sapienza University, Rome, Italy
| | - Andrzej Pilc
- Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
| | - Francesco Fazio
- I.R.C.C.S. Neuromed, Pozzilli, Italy,To whom correspondence should be addressed; Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Rose F. Kennedy Center, 1410 Pelham Parkway South, room 610, New York City, NY, USA; tel: +1-718-430-2160, fax: +1-718-430-8932, e-mail:
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28
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Marek GJ, Salek AA. Extending the Specificity of DRL 72-s Behavior for Screening Antidepressant-Like Effects of Glutamatergic Clinically Validated Anxiolytic or Antidepressant Drugs in Rats. J Pharmacol Exp Ther 2020; 374:200-210. [PMID: 32265323 DOI: 10.1124/jpet.119.264069] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 03/13/2020] [Indexed: 12/26/2022] Open
Abstract
Both an agonist and its associated prodrug for metabotropic glutamate2/3 (mGlu2/3) receptors demonstrated anxiolytic efficacy in large, randomized, multicenter, double-blind, placebo-controlled trials studying patients with generalized anxiety disorder (GAD). These mGlu2/3 receptor agonists produced robust preclinical anxiolytic-like effects in rodent models. Several different metabotropic glutamate2 receptor positive allosteric modulators have been found to produce antidepressant-like effects on several preclinical screening paradigms, including differential-reinforcement-of-low-rate 72-second (DRL 72-s) behavior [increased reinforcers, decreased response rate, and cohesive rightward shifts in inter-response time distributions]. Although mGlu2/3 receptor agonists have not been tested formally for therapeutic effects in treating patients with major depressive disorder, these compounds generally fail to exert antidepressant-like effects in preclinical screening paradigms and did not improve depressive symptoms in GAD trials. Thus, the present studies were designed to test the potential antidepressant-like effects of the mGlu2/3 receptor agonist 1S,2S,5R,6S-2-aminobicyclo[3.1.0]hexane-2,6-bicarboxylate monohydrate (LY354740) on the DRL 72-s schedule. LY354740 did not test similarly to clinically validated antidepressant drugs when administered alone or when coadministered with the selective serotonin reuptake inhibitor fluoxetine in rats. Another glutamate-based antidepressant drug, the uncompetitive N-methyl-D-aspartate channel blocker racemic ketamine, exerted antidepressant-like effects when administered at subanesthetic doses in rats. The findings further support the specificity of rat DRL 72-s behavior when screening for anxiolytic versus antidepressant drugs and extend testing of compounds with glutamatergic mechanisms of action. SIGNIFICANCE STATEMENT: The metabotropic glutamate2/3 receptor agonist and clinically validated anxiolytic drug 1S,2S,5R,6S-2-aminobicyclo[3.1.0]hexane-2,6-bicarboxylate monohydrate did not test similar to antidepressant drugs (increased reinforcers, decreased response rate, and cohesive rightward shifts in the inter-response time distribution) when tested on differential-reinforcement-of-low-rate 72-second (DRL 72-s) behavior and also did not enhance the antidepressant-like effects of the serotonin reuptake inhibitor fluoxetine. The uncompetitive N-methyl-D-aspartate receptor antagonist ketamine increased the reinforcement rate, decreased the response rate, and induced a rightward shift in the inter-response time distribution similar to antidepressant drugs; these results confirm the utility of DRL 72-s schedule of reinforcement when testing clinically validated anxiolytic versus antidepressant glutamatergic drugs.
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Affiliation(s)
- Gerard J Marek
- Yale School of Medicine Department of Psychiatry, Ribicoff Research Facilities of the Connecticut Mental Health Center, New Haven, Connecticut
| | - Allyson A Salek
- Yale School of Medicine Department of Psychiatry, Ribicoff Research Facilities of the Connecticut Mental Health Center, New Haven, Connecticut
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29
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dos Santos RG, Hallak JEC. Therapeutic use of serotoninergic hallucinogens: A review of the evidence and of the biological and psychological mechanisms. Neurosci Biobehav Rev 2020; 108:423-434. [DOI: 10.1016/j.neubiorev.2019.12.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Revised: 11/05/2019] [Accepted: 12/02/2019] [Indexed: 12/20/2022]
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30
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Pham X, Wright DK, Atapour N, Chan JMH, Watkins KJ, Worthy KH, Rosa M, Reichelt A, Reser DH. Internal Subdivisions of the Marmoset Claustrum Complex: Identification by Myeloarchitectural Features and High Field Strength Imaging. Front Neuroanat 2019; 13:96. [PMID: 31827427 PMCID: PMC6890826 DOI: 10.3389/fnana.2019.00096] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 11/14/2019] [Indexed: 11/23/2022] Open
Abstract
There has been a surge of interest in the structure and function of the mammalian claustrum in recent years. However, most anatomical and physiological studies treat the claustrum as a relatively homogenous structure. Relatively little attention has been directed toward possible compartmentalization of the claustrum complex into anatomical subdivisions, and how this compartmentalization is reflected in claustrum connections with other brain structures. In this study, we examined the cyto- and myelo-architecture of the claustrum of the common marmoset (Callithrix jacchus), to determine whether the claustrum contains internal anatomical structures or compartments, which could facilitate studies focused on understanding its role in brain function. NeuN, Nissl, calbindin, parvalbumin, and myelin-stained sections from eight adult marmosets were studied using light microscopy and serial reconstruction to identify potential internal compartments. Ultra high resolution (9.4T) post-mortem magnetic resonance imaging was employed to identify tractographic differences between identified claustrum subcompartments by diffusion-weighted tractography. Our results indicate that the classically defined marmoset claustrum includes at least two major subdivisions, which correspond to the dorsal endopiriform and insular claustrum nuclei, as described in other species, and that the dorsal endopiriform nucleus (DEnD) contains architecturally distinct compartments. Furthermore, the dorsal subdivision of the DEnD is tractographically distinguishable from the insular claustrum with respect to cortical connections.
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Affiliation(s)
| | - David K Wright
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia.,The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
| | - Nafiseh Atapour
- Department of Physiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia.,Australian Research Council Centre of Excellence for Integrative Brain Function, Monash University Node, Clayton, VIC, Australia
| | - Jonathan M-H Chan
- Department of Physiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia.,Australian Research Council Centre of Excellence for Integrative Brain Function, Monash University Node, Clayton, VIC, Australia
| | - Kirsty J Watkins
- The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
| | - Katrina H Worthy
- Department of Physiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Marcello Rosa
- Department of Physiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia.,Australian Research Council Centre of Excellence for Integrative Brain Function, Monash University Node, Clayton, VIC, Australia
| | - Amy Reichelt
- The Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia.,Robarts Research Institute, Western University, London, ON, Canada
| | - David H Reser
- Department of Physiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia.,Graduate Entry Medicine Program, Monash Rural Health, Churchill, VIC, Australia
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31
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Carhart-Harris RL, Friston KJ. REBUS and the Anarchic Brain: Toward a Unified Model of the Brain Action of Psychedelics. Pharmacol Rev 2019; 71:316-344. [PMID: 31221820 PMCID: PMC6588209 DOI: 10.1124/pr.118.017160] [Citation(s) in RCA: 342] [Impact Index Per Article: 68.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
This paper formulates the action of psychedelics by integrating the free-energy principle and entropic brain hypothesis. We call this formulation relaxed beliefs under psychedelics (REBUS) and the anarchic brain, founded on the principle that-via their entropic effect on spontaneous cortical activity-psychedelics work to relax the precision of high-level priors or beliefs, thereby liberating bottom-up information flow, particularly via intrinsic sources such as the limbic system. We assemble evidence for this model and show how it can explain a broad range of phenomena associated with the psychedelic experience. With regard to their potential therapeutic use, we propose that psychedelics work to relax the precision weighting of pathologically overweighted priors underpinning various expressions of mental illness. We propose that this process entails an increased sensitization of high-level priors to bottom-up signaling (stemming from intrinsic sources), and that this heightened sensitivity enables the potential revision and deweighting of overweighted priors. We end by discussing further implications of the model, such as that psychedelics can bring about the revision of other heavily weighted high-level priors, not directly related to mental health, such as those underlying partisan and/or overly-confident political, religious, and/or philosophical perspectives. SIGNIFICANCE STATEMENT: Psychedelics are capturing interest, with efforts underway to bring psilocybin therapy to marketing authorisation and legal access within a decade, spearheaded by the findings of a series of phase 2 trials. In this climate, a compelling unified model of how psychedelics alter brain function to alter consciousness would have appeal. Towards this end, we have sought to integrate a leading model of global brain function, hierarchical predictive coding, with an often-cited model of the acute action of psychedelics, the entropic brain hypothesis. The resulting synthesis states that psychedelics work to relax high-level priors, sensitising them to liberated bottom-up information flow, which, with the right intention, care provision and context, can help guide and cultivate the revision of entrenched pathological priors.
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Affiliation(s)
- R L Carhart-Harris
- Centre for Psychedelic Research, Division of Brain Sciences, Imperial College London, London, United Kingdom (R.L.C.-H.); and Institute of Neurology, Wellcome Trust Centre for Neuroimaging, University College London, London, United Kingdom (K.J.F.)
| | - K J Friston
- Centre for Psychedelic Research, Division of Brain Sciences, Imperial College London, London, United Kingdom (R.L.C.-H.); and Institute of Neurology, Wellcome Trust Centre for Neuroimaging, University College London, London, United Kingdom (K.J.F.)
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32
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de Almeida RN, Galvão ACDM, da Silva FS, Silva EADS, Palhano-Fontes F, Maia-de-Oliveira JP, de Araújo LSB, Lobão-Soares B, Galvão-Coelho NL. Modulation of Serum Brain-Derived Neurotrophic Factor by a Single Dose of Ayahuasca: Observation From a Randomized Controlled Trial. Front Psychol 2019; 10:1234. [PMID: 31231276 PMCID: PMC6558429 DOI: 10.3389/fpsyg.2019.01234] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 05/10/2019] [Indexed: 01/01/2023] Open
Abstract
Serotonergic psychedelics are emerging as potential antidepressant therapeutic tools, as suggested in a recent randomized controlled trial with ayahuasca for treatment-resistant depression. Preclinical and clinical studies have suggested that serum brain-derived neurotrophic factor (BDNF) levels increase after treatment with serotoninergic antidepressants, but the exact role of BDNF as a biomarker for diagnostic and treatment of major depression is still poorly understood. Here we investigated serum BDNF levels in healthy controls (N = 45) and patients with treatment-resistant depression (N = 28) before (baseline) and 48 h after (D2) a single dose of ayahuasca or placebo. In our sample, baseline serum BDNF levels did not predict major depression and the clinical characteristics of the patients did not predict their BDNF levels. However, at baseline, serum cortisol was a predictor of serum BDNF levels, where lower levels of serum BDNF were detected in a subgroup of subjects with hypocortisolemia. Moreover, at baseline we found a negative correlation between BDNF and serum cortisol in volunteers with eucortisolemia. After treatment (D2) we observed higher BDNF levels in both patients and controls that ingested ayahuasca (N = 35) when compared to placebo (N = 34). Furthermore, at D2 just patients treated with ayahuasca (N = 14), and not with placebo (N = 14), presented a significant negative correlation between serum BDNF levels and depressive symptoms. This is the first double-blind randomized placebo-controlled clinical trial that explored the modulation of BDNF in response to a psychedelic in patients with depression. The results suggest a potential link between the observed antidepressant effects of ayahuasca and changes in serum BDNF, which contributes to the emerging view of using psychedelics as an antidepressant. This trial is registered at http://clinicaltrials.gov (NCT02914769).
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Affiliation(s)
- Raíssa Nóbrega de Almeida
- Laboratory of Hormone Measurement, Department of Physiology and Behavior, Federal University of Rio Grande do Norte, Natal, Brazil
- Postgraduate Program in Psychobiology, Department of Physiology and Behavior, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Ana Cecília de Menezes Galvão
- Laboratory of Hormone Measurement, Department of Physiology and Behavior, Federal University of Rio Grande do Norte, Natal, Brazil
- Postgraduate Program in Psychobiology, Department of Physiology and Behavior, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Flávia Santos da Silva
- Laboratory of Hormone Measurement, Department of Physiology and Behavior, Federal University of Rio Grande do Norte, Natal, Brazil
- Postgraduate Program in Psychobiology, Department of Physiology and Behavior, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Erick Allan dos Santos Silva
- Laboratory of Hormone Measurement, Department of Physiology and Behavior, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Fernanda Palhano-Fontes
- Onofre Lopes University Hospital, Federal University of Rio Grande do Norte, Natal, Brazil
- Brain Institute, Federal University of Rio Grande do Norte, Natal, Brazil
| | - João Paulo Maia-de-Oliveira
- Onofre Lopes University Hospital, Federal University of Rio Grande do Norte, Natal, Brazil
- National Science and Technology Institute for Translational Medicine (INCT-TM), Natal, Brazil
- Department of Clinical Medicine, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Lobão-Soares Barros de Araújo
- Onofre Lopes University Hospital, Federal University of Rio Grande do Norte, Natal, Brazil
- Brain Institute, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Bruno Lobão-Soares
- National Science and Technology Institute for Translational Medicine (INCT-TM), Natal, Brazil
- Department of Biophysics and Pharmacology, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Nicole Leite Galvão-Coelho
- Laboratory of Hormone Measurement, Department of Physiology and Behavior, Federal University of Rio Grande do Norte, Natal, Brazil
- Postgraduate Program in Psychobiology, Department of Physiology and Behavior, Federal University of Rio Grande do Norte, Natal, Brazil
- National Science and Technology Institute for Translational Medicine (INCT-TM), Natal, Brazil
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33
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Dos Santos RG, Bouso JC, Alcázar-Córcoles MÁ, Hallak JEC. Efficacy, tolerability, and safety of serotonergic psychedelics for the management of mood, anxiety, and substance-use disorders: a systematic review of systematic reviews. Expert Rev Clin Pharmacol 2018; 11:889-902. [PMID: 30102078 DOI: 10.1080/17512433.2018.1511424] [Citation(s) in RCA: 110] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
INTRODUCTION Mood, anxiety, and substance-use disorders are among the most prevalent psychiatric disorders in the population. Although several pharmacological treatments are available, they are not effective for a significant proportion of patients and are associated with several adverse reactions. Therefore, new treatments should be explored. Recent studies suggest that serotonergic hallucinogens/psychedelics including ayahuasca, psilocybin, and lysergic acid diethylamide (LSD) have anxiolytic, antidepressive, and antiaddictive effects. Areas Covered: A systematic review of systematic reviews assessing the efficacy, safety, and tolerability of serotonergic hallucinogens/psychedelic was performed using the PubMed data base until 11 April 2018. Systematic reviews with or without meta-analysis were analyzed, but only reviews that described at least one randomized controlled trial (RCT) were included. Expert Commentary: Psilocybin and LSD reduced anxiety and depression in cancer patients and symptoms of alcohol and tobacco dependence, and ayahuasca reduced depression symptoms in treatment-resistant depression. Although the results are promising, several studies were open label, and only few were RCTs, and most had small sample sizes and a short duration. Single or few doses of these drugs seem to be well tolerated, but long-term studies are lacking. New RCTs with bigger samples and longer duration are needed to replicate these findings.
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Affiliation(s)
- Rafael G Dos Santos
- a ICEERS Foundation (International Center for Ethnobotanical Education, Research and Services) , Barcelona , Spain.,b Department of Neurosciences and Behavior, Ribeirão Preto Medical School , University of São Paulo , Ribeirão Preto , Brazil.,c Translational Medicine , National Institute of Science and Technology , Ribeirão Preto , Brazil
| | - José Carlos Bouso
- a ICEERS Foundation (International Center for Ethnobotanical Education, Research and Services) , Barcelona , Spain
| | - Miguel Ángel Alcázar-Córcoles
- d Departamento de Psicología Biológica y de la Salud. Facultad de Psicología , Universidad Autónoma de Madrid , Madrid , Spain
| | - Jaime E C Hallak
- b Department of Neurosciences and Behavior, Ribeirão Preto Medical School , University of São Paulo , Ribeirão Preto , Brazil.,c Translational Medicine , National Institute of Science and Technology , Ribeirão Preto , Brazil
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Benvenga MJ, Chaney SF, Baez M, Britton TC, Hornback WJ, Monn JA, Marek GJ. Metabotropic Glutamate 2 Receptors Play a Key Role in Modulating Head Twitches Induced by a Serotonergic Hallucinogen in Mice. Front Pharmacol 2018; 9:208. [PMID: 29599719 PMCID: PMC5862811 DOI: 10.3389/fphar.2018.00208] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 02/23/2018] [Indexed: 11/29/2022] Open
Abstract
There is substantial evidence that glutamate can modulate the effects of 5-hydroxytryptamine2A (5-HT2A) receptor activation through stimulation of metabotropic glutamate2/3 (mGlu2/3) receptors in the prefrontal cortex. Here we show that constitutive deletion of the mGlu2 gene profoundly attenuates an effect of 5-HT2A receptor activation using the mouse head twitch response (HTR). MGlu2 and mGlu3 receptor knockout (KO) as well as age-matched ICR (CD-1) wild type (WT) mice were administered (±)1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) and observed for head twitch activity. DOI failed to produce significant head twitches in mGlu2 receptor KO mice at a dose 10-fold higher than the peak effective dose in WT or mGlu3 receptor KO mice. In addition, the mGlu2/3 receptor agonist LY379268, and the mGlu2 receptor positive allosteric modulator (PAM) CBiPES, potently blocked the HTR to DOI in WT and mGlu3 receptor KO mice. Conversely, the mGlu2/3 receptor antagonist LY341495 (10 mg/kg) increased the HTR produced by DOI (3 mg/kg) in mGlu3 receptor KO mice. Finally, the mGlu2 receptor potentiator CBiPES was able to attenuate the increase in the HTR produced by LY341495 in mGlu3 receptor KO mice. Taken together, all of these results are consistent with the hypothesis that that DOI-induced head twitches are modulated by mGlu2 receptor activation. These results also are in keeping with a critical autoreceptor function for mGlu2 receptors in the prefrontal cortex with differential effects of acute vs. chronic perturbation (e.g., constitutive mGlu2 receptor KO mice). The robust attenuation of DOI-induced head twitches in the mGlu2 receptor KO mice appears to reflect the critical role of glutamate in ongoing regulation of 5-HT2A receptors in the prefrontal cortex. Future experiments with inducible knockouts for the mGlu2 receptor and/or selective mGlu3 receptor agonists/PAMs/antagonists could provide an important tools in understanding glutamatergic modulation of prefrontal cortical 5-HT2A receptor function.
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Affiliation(s)
- Mark J Benvenga
- Neuroscience Discovery Research, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, United States.,Lilly Corporate Center, Eli Lilly and Company, Indianapolis, IN, United States
| | - Stephen F Chaney
- Neuroscience Discovery Research, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, United States
| | - Melvyn Baez
- Neuroscience Discovery Research, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, United States
| | - Thomas C Britton
- Discovery Chemistry Research, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, United States
| | - William J Hornback
- Discovery Chemistry Research, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, United States
| | - James A Monn
- Discovery Chemistry Research, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, United States
| | - Gerard J Marek
- Neuroscience Discovery Research, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, United States
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35
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Marek GJ, Ramos BP. β 2-Adrenergic Receptor Activation Suppresses the Rat Phenethylamine Hallucinogen-Induced Head Twitch Response: Hallucinogen-Induced Excitatory Post-synaptic Potentials as a Potential Substrate. Front Pharmacol 2018; 9:89. [PMID: 29472863 PMCID: PMC5809958 DOI: 10.3389/fphar.2018.00089] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 01/26/2018] [Indexed: 12/20/2022] Open
Abstract
5-Hydroxytryptamine2A (5-HT2A) receptors are enriched in layers I and Va of the rat prefrontal cortex and neocortex and their activation increases the frequency of glutamatergic excitatory post-synaptic potentials/currents (EPSP/Cs) onto layer V pyramidal cells. A number of other G-protein coupled receptors (GPCRs) are also enriched in cortical layers I and Va and either induce (α1-adrenergic and orexin2) or suppress (metabotropic glutamate2 [mGlu2], adenosine A1, μ-opioid) both 5-HT-induced EPSCs and head twitches or head shakes induced by the phenethylamine hallucinogen 2,5-dimethoxy-4-iodoamphetamine (DOI). Another neurotransmitter receptor also localized to apparent thalamocortical afferents to layers I and Va of the rat prefrontal cortex and neocortex is the β2-adrenergic receptor. Therefore, we conducted preliminary electrophysiological experiments with rat brain slices examining the effects of epinephrine on electrically-evoked EPSPs following bath application of DOI (3 μM). Epinephrine (0.3-10 μM) suppressed the late EPSPs produced by electrical stimulation and DOI. The selective β2-adrenergic receptor antagonist ICI-118,551 (300 nM) resulted in a rightward shift of the epinephrine concentration-response relationship. We also tested the selective β2-adrenergic receptor agonist clenbuterol and the antagonist ICI-118,551 on DOI-induced head twitches. Clenbuterol (0.3-3 mg/kg, i.p.) suppressed DOI (1.25 mg/kg, i.p.)-induced head twitches. This clenbuterol effect appeared to be at least partially reversed by the selective β2-adrenergic receptor antagonist ICI-118,553 (0.01-1 mg/kg, i.p.), with significant reversal at doses of 0.1 and 1 mg/kg. Thus, β2-adrenergic receptor activation reverses the effects of phenethylamine hallucinogens in the rat prefrontal cortex. While Gi/Go-coupled GPCRs have previously been shown to suppress both the electrophysiological and behavioral effects of 5-HT2A receptor activation in the mPFC, the present work appears to extend this suppressant action to a Gs-coupled GPCR. Furthermore, the modulation of 5-HT2A receptor activation-induced glutamate release onto mPFC layer V pyramidal neurons apical dendrites by a range GPCRs in rat brain slices appears to results in behaviorally salient effects of relevance when screening for novel CNS therapeutic drugs.
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Affiliation(s)
- Gerard J. Marek
- Department of Psychiatry, School of Medicine, Ribicoff Research Facilities of the Connecticut Mental Health Center, Yale University, New Haven, CT, United States
- Astellas Pharma Global Development, Inc., Global Medical Science, CNS and Pain, Northbrook, IL, United States
| | - Brian P. Ramos
- Department of Neurobiology, School of Medicine, Yale University, New Haven, CT, United States
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