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Frontiers in Pharmacology 2024, psilocybin is rapidly dephosphorylated to psilocin which induces psychedelic effects by interacting with the 5-HT receptor. Psilocin primarily undergoes...
, psilocybin is rapidly dephosphorylated to psilocin which induces psychedelic effects by interacting with the 5-HT receptor. Psilocin primarily undergoes glucuronidation or conversion to 4-hydroxyindole-3-acetic acid (4-HIAA). Herein, we investigated psilocybin's metabolic pathways and , conducting a thorough analysis of the enzymes involved. Metabolism studies were performed using human liver microsomes (HLM), cytochrome P450 (CYP) enzymes, monoamine oxidase (MAO), and UDP-glucuronosyltransferase (UGT). , metabolism was examined using male C57BL/6J mice and human plasma samples. Approximately 29% of psilocin was metabolized by HLM, while recombinant CYP2D6 and CYP3A4 enzymes metabolized nearly 100% and 40% of psilocin, respectively. Notably, 4-HIAA and 4-hydroxytryptophol (4-HTP) were detected with HLM but not with recombinant CYPs. MAO-A transformed psilocin into minimal amounts of 4-HIAA and 4-HTP. 4-HTP was only present . Neither 4-HIAA nor 4-HTP showed relevant interactions at assessed 5-HT receptors. In contrast to data, UGT1A10 did not extensively metabolize psilocin . Furthermore, two putative metabolites were observed. -methyl-4-hydroxytryptamine (norpsilocin) was identified (CYP2D6) and in mice, while an oxidized metabolite was detected (CYP2D6) and in humans. However, the CYP2D6 genotype did not influence psilocin plasma concentrations in the investigated study population. In conclusion, MAO-A, CYP2D6, and CYP3A4 are involved in psilocin's metabolism. The discovery of putative norpsilocin in mice and oxidized psilocin in humans further unravels psilocin's metabolism. Despite limitations in replicating phase II metabolism , these findings hold significance for studying drug-drug interactions and advancing research on psilocybin as a therapeutic agent.
PubMed: 38741590
DOI: 10.3389/fphar.2024.1391689 -
Cancers Apr 2024Despite the legalization of psilocybin therapy for depression in terminal illnesses such as advanced cancer through Oregon's Measure 109 in 2020, significant challenges... (Review)
Review
Despite the legalization of psilocybin therapy for depression in terminal illnesses such as advanced cancer through Oregon's Measure 109 in 2020, significant challenges have impeded its implementation. This review synthesizes the empirical data supporting the utilization of psilocybin therapy for addressing cancer-related depression, including an evaluation of its purported benefits and potential adverse effects. It provides a comprehensive examination of therapeutic strategies, dosing regimens, and barriers to ensuring responsible and equitable access. Salient issues explored include the development of ethical protocols, integration within healthcare systems, ensuring statewide availability, resolving legal ambiguities, and defining clinical standards. Oregon's pioneering role serves as a case study, highlighting the necessity of addressing regulatory, logistical, and ethical obstacles to ensure the establishment of rigorous and equitable psilocybin care models.
PubMed: 38730654
DOI: 10.3390/cancers16091702 -
BJPsych Open May 2024In this editorial, we emphasise the efficacy and challenges of using ketamine in treatment-resistant depression. We highlight the need for comprehensive evidence-based...
In this editorial, we emphasise the efficacy and challenges of using ketamine in treatment-resistant depression. We highlight the need for comprehensive evidence-based guidelines to manage the use of both licensed and off-licence ketamine formulations and discuss recent efforts by Beaglehole et al to develop ketamine guidelines in New Zealand. We finally advocate for national registries to monitor ketamine therapy, ensuring its responsible and effective use in the management of depression.
PubMed: 38725375
DOI: 10.1192/bjo.2024.62 -
Nature Jun 2024Psychedelic substances such as lysergic acid diethylamide (LSD) and psilocybin show potential for the treatment of various neuropsychiatric disorders. These compounds...
Psychedelic substances such as lysergic acid diethylamide (LSD) and psilocybin show potential for the treatment of various neuropsychiatric disorders. These compounds are thought to mediate their hallucinogenic and therapeutic effects through the serotonin (5-hydroxytryptamine (5-HT)) receptor 5-HT (ref. ). However, 5-HT also plays a part in the behavioural effects of tryptamine hallucinogens, particularly 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT), a psychedelic found in the toxin of Colorado River toads. Although 5-HT is a validated therapeutic target, little is known about how psychedelics engage 5-HT and which effects are mediated by this receptor. Here we map the molecular underpinnings of 5-MeO-DMT pharmacology through five cryogenic electron microscopy (cryo-EM) structures of 5-HT, systematic medicinal chemistry, receptor mutagenesis and mouse behaviour. Structure-activity relationship analyses of 5-methoxytryptamines at both 5-HT and 5-HT enable the characterization of molecular determinants of 5-HT signalling potency, efficacy and selectivity. Moreover, we contrast the structural interactions and in vitro pharmacology of 5-MeO-DMT and analogues to the pan-serotonergic agonist LSD and clinically used 5-HT agonists. We show that a 5-HT-selective 5-MeO-DMT analogue is devoid of hallucinogenic-like effects while retaining anxiolytic-like and antidepressant-like activity in socially defeated animals. Our studies uncover molecular aspects of 5-HT-targeted psychedelics and therapeutics, which may facilitate the future development of new medications for neuropsychiatric disorders.
Topics: Animals; Humans; Male; Mice; 5-Methoxytryptamine; Anti-Anxiety Agents; Antidepressive Agents; Cryoelectron Microscopy; Hallucinogens; Lysergic Acid Diethylamide; Methoxydimethyltryptamines; Models, Molecular; Receptor, Serotonin, 5-HT1A; Receptor, Serotonin, 5-HT2A; Serotonin Receptor Agonists; Structure-Activity Relationship
PubMed: 38720072
DOI: 10.1038/s41586-024-07403-2 -
Frontiers in Psychiatry 2024Patients with incurable illnesses often experience existential distress, profoundly impacting their well-being. Current medical approaches have limitations in addressing...
INTRODUCTION
Patients with incurable illnesses often experience existential distress, profoundly impacting their well-being. Current medical approaches have limitations in addressing these burdens. Psilocybin, a promising psychedelic compound, may offer therapeutic benefits. This pilot survey study aimed to investigate the attitudes and openness toward psilocybin-assisted psychotherapy (PAT) among patients with incurable illnesses. The objective is to assess patients' attitudes toward PAT and identify potential barriers and concerns, including exploring the association between beliefs in psilocybin's therapeutic benefits and interest in receiving this treatment.
METHODS
The survey study was conducted at the Tampa General Hospital Palliative Care Outpatient office in the United States. Participants were 32 English-fluent patients, aged 18 or older, with incurable illnesses. The survey included demographic questions, a validated tool to measure existential distress, and questions about knowledge and concerns regarding psilocybin. Attitudes toward PAT and interest in its future use were assessed using Likert scale responses.
RESULTS
Among the 31 analyzed participants, 51.6% expressed interest in future psilocybin treatment, while 32.3% did not indicate interest. Belief in the psilocybin's therapeutic benefits for stress and anxiety significantly correlated with interest in use. Concerns included risk of psychosis, lack of trained providers, and potential for exploitation. No demographic factors were associated with interest or levels of distress.
CONCLUSIONS
This pilot study provides insights into the attitudes and concerns toward PAT among patients with incurable illnesses. Over half of participants expressed interest. However, concerns regarding its use were identified, with patients' concern for the risk of exploitation associated with PAT as an especially novel concern documented in this patient population. This highlighted the need for further education of risks and benefits or PAT by trained clinicians and rigorous training of clinicians with the establishment of safeguards against exploitation. Further research is necessary to explore the potential benefits of PAT and related non-psilocybin psychedelic compounds in addressing existential distress among patients with incurable illnesses.
PubMed: 38699449
DOI: 10.3389/fpsyt.2024.1301960 -
Frontiers in Pharmacology 2024Immediate early genes (IEGs) are rapidly activated and initiate diverse cellular processes including neuroplasticity. We report the effect of psilocybin (PSIL),...
Immediate early genes (IEGs) are rapidly activated and initiate diverse cellular processes including neuroplasticity. We report the effect of psilocybin (PSIL), PSIL-containing psychedelic mushroom extract (PME) and 5-hydroxytryptophan (5-HTP) on expression of the IEGs, , and in mouse somatosensory cortex (SSC). In our initial experiment, male C57Bl/6j mice were injected with PSIL 4.4 mg/kg or 5-HTP 200 mg/kg, alone or immediately preceded by serotonergic receptor modulators. IEG mRNA expression 1 hour later was determined by real time qPCR. In a replication study a group of mice treated with PME was added. In our initial experiment, PSIL but not 5-HTP significantly increased expression of all three IEGs. No correlation was observed between the head twitch response (HTR) induced by PSIL and its effect on the IEGs. The serotonergic receptor modulators did not significantly alter PSIL-induced IEG expression, with the exception of the 5-HT2C antagonist (RS102221), which significantly enhanced PSIL-induced egr2 expression. 5-HTP did not affect IEG expression. In our replication experiment, PSIL and PME upregulated levels of and while the upregulation of was not significant. We have shown that PSIL and PME but not 5-HTP (at a dose sufficient to induce HTR), induced a significant increase in and expression in mouse SSC. Our findings suggest that and expression may be associated with psychedelic effects.
PubMed: 38698823
DOI: 10.3389/fphar.2024.1391412 -
Cell Death Discovery May 2024Depression is highly prevalent globally, however, currently available medications face challenges such as low response rates and short duration of efficacy.... (Review)
Review
Depression is highly prevalent globally, however, currently available medications face challenges such as low response rates and short duration of efficacy. Additionally, depression mostly accompany other psychiatric disorders, further progressing to major depressive disorder without long-term effective management. Thus, sustained antidepressant strategies are urgently needed. Recently, ketamine and psilocybin gained attention as potential sustained antidepressants. Review of recent studies highlights that synaptic plasticity changes as key events of downstream long-lasting changes in sustained antidepressant effect. This underscores the significance of synaptic plasticity in sustained antidepressant effect. Moreover, neurexins, key molecules involved in the regulation of synaptic plasticity, act as critical links between synaptic plasticity and sustained antidepressant effects, involving mechanisms including protein level, selective splicing, epigenetics, astrocytes, positional redistribution and protein structure. Based on the regulation of synaptic plasticity by neurexins, several drugs with potential for sustained antidepressant effect are also discussed. Focusing on neurexins in regulating synaptic plasticity promises much for further understanding underlying mechanisms of sustained antidepressant and the next step in new drug development. This research represents a highly promising future research direction.
PubMed: 38693106
DOI: 10.1038/s41420-024-01974-9 -
BMJ (Clinical Research Ed.) May 2024To determine the efficacy of psilocybin as an antidepressant compared with placebo or non-psychoactive drugs. (Meta-Analysis)
Meta-Analysis
OBJECTIVE
To determine the efficacy of psilocybin as an antidepressant compared with placebo or non-psychoactive drugs.
DESIGN
Systematic review and meta-analysis.
DATA SOURCES
Five electronic databases of published literature (Cochrane Central Register of Controlled Trials, Medline, Embase, Science Citation Index and Conference Proceedings Citation Index, and PsycInfo) and four databases of unpublished and international literature (ClinicalTrials.gov, WHO International Clinical Trials Registry Platform, ProQuest Dissertations and Theses Global, and PsycEXTRA), and handsearching of reference lists, conference proceedings, and abstracts.
DATA SYNTHESIS AND STUDY QUALITY
Information on potential treatment effect moderators was extracted, including depression type (primary or secondary), previous use of psychedelics, psilocybin dosage, type of outcome measure (clinician rated or self-reported), and personal characteristics (eg, age, sex). Data were synthesised using a random effects meta-analysis model, and observed heterogeneity and the effect of covariates were investigated with subgroup analyses and metaregression. Hedges' g was used as a measure of treatment effect size, to account for small sample effects and substantial differences between the included studies' sample sizes. Study quality was appraised using Cochrane's Risk of Bias 2 tool, and the quality of the aggregated evidence was evaluated using GRADE guidelines.
ELIGIBILITY CRITERIA
Randomised trials in which psilocybin was administered as a standalone treatment for adults with clinically significant symptoms of depression and change in symptoms was measured using a validated clinician rated or self-report scale. Studies with directive psychotherapy were included if the psychotherapeutic component was present in both experimental and control conditions. Participants with depression regardless of comorbidities (eg, cancer) were eligible.
RESULTS
Meta-analysis on 436 participants (228 female participants), average age 36-60 years, from seven of the nine included studies showed a significant benefit of psilocybin (Hedges' g=1.64, 95% confidence interval (CI) 0.55 to 2.73, P<0.001) on change in depression scores compared with comparator treatment. Subgroup analyses and metaregressions indicated that having secondary depression (Hedges' g=3.25, 95% CI 0.97 to 5.53), being assessed with self-report depression scales such as the Beck depression inventory (3.25, 0.97 to 5.53), and older age and previous use of psychedelics (metaregression coefficient 0.16, 95% CI 0.08 to 0.24 and 4.2, 1.5 to 6.9, respectively) were correlated with greater improvements in symptoms. All studies had a low risk of bias, but the change from baseline metric was associated with high heterogeneity and a statistically significant risk of small study bias, resulting in a low certainty of evidence rating.
CONCLUSION
Treatment effects of psilocybin were significantly larger among patients with secondary depression, when self-report scales were used to measure symptoms of depression, and when participants had previously used psychedelics. Further research is thus required to delineate the influence of expectancy effects, moderating factors, and treatment delivery on the efficacy of psilocybin as an antidepressant.
SYSTEMATIC REVIEW REGISTRATION
PROSPERO CRD42023388065.
Topics: Humans; Antidepressive Agents; Depression; Hallucinogens; Psilocybin; Randomized Controlled Trials as Topic; Treatment Outcome
PubMed: 38692686
DOI: 10.1136/bmj-2023-078084 -
Brain Sciences Mar 2024Cluster headache (CH) is a debilitating condition, but current therapies leave CH patients in pain. The extent of this problem in Sweden is unknown.
BACKGROUND
Cluster headache (CH) is a debilitating condition, but current therapies leave CH patients in pain. The extent of this problem in Sweden is unknown.
METHODS
An anonymized questionnaire was sent to 479 Swedish CH patients to investigate patterns and perceived effects of treatments.
RESULTS
Three hundred fourteen answers were analyzed. The population was representative regarding age of onset and sex. Less than half (46%) were satisfied with their abortive treatments, 19% terminated functioning abortive treatments due to side effects. Additionally, 17% of chronic CH patients had not tried the first-line preventive drug verapamil. A small subset had tried illicit substances to treat their CH (0-8% depending on substance). Notably, psilocybin was reported effective as an abortive treatment by 100% ( = 8), and with some level of effect as a preventive treatment by 92% ( = 12). For verapamil, some level of preventive effect was reported among 68% ( = 85).
CONCLUSIONS
Our descriptive data illustrate that many Swedish CH patients are undertreated, lack functional therapies, and experience side effects. Further studies are warranted to search for new treatment strategies as well as a revision of current treatment guidelines with the aim of reducing patient disease burden to the greatest extent possible.
PubMed: 38672000
DOI: 10.3390/brainsci14040348 -
Fungal Biology and Biotechnology Apr 2024Although Basidiomycota produce pharmaceutically and ecologically relevant natural products, knowledge of how they coordinate their primary and secondary metabolism is...
BACKGROUND
Although Basidiomycota produce pharmaceutically and ecologically relevant natural products, knowledge of how they coordinate their primary and secondary metabolism is virtually non-existent. Upon transition from vegetative mycelium to carpophore formation, mushrooms of the genus Psilocybe use L-tryptophan to supply the biosynthesis of the psychedelic tryptamine alkaloid psilocybin with the scaffold, leading to a strongly increased demand for this particular amino acid as this alkaloid may account for up to 2% of the dry mass. Using Psilocybe mexicana as our model and relying on genetic, transcriptomic, and biochemical methods, this study investigated if L-tryptophan biosynthesis and degradation in P. mexicana correlate with natural product formation.
RESULTS
A comparative transcriptomic approach of gene expression in P. mexicana psilocybin non-producing vegetative mycelium versus producing carpophores identified the upregulation of L-tryptophan biosynthesis genes. The shikimate pathway genes trpE1, trpD, and trpB (encoding anthranilate synthase, anthranilate phosphoribosyltransferase, and L-tryptophan synthase, respectively) were upregulated in carpophores. In contrast, genes idoA and iasA, encoding indole-2,3-dioxygenase and indole-3-acetaldehyde synthase, i.e., gateway enzymes for L-tryptophan-consuming pathways, were massively downregulated. Subsequently, IasA was heterologously produced in Escherichia coli and biochemically characterized in vitro. This enzyme represents the first characterized microbial L-tryptophan-preferring acetaldehyde synthase. A comparison of transcriptomic data collected in this study with prior data of Psilocybe cubensis showed species-specific differences in how L-tryptophan metabolism genes are regulated, despite the close taxonomic relationship.
CONCLUSIONS
The upregulated L-tryptophan biosynthesis genes and, oppositely, the concomitant downregulated genes encoding L-tryptophan-consuming enzymes reflect a well-adjusted cellular system to route this amino acid toward psilocybin production. Our study has pilot character beyond the genus Psilocybe and provides, for the first time, insight in the coordination of mushroom primary and secondary metabolism.
PubMed: 38664850
DOI: 10.1186/s40694-024-00173-6