Administration of N,N-dimethyltryptamine (DMT) in psychedelic therapeutics and research and the study of endogenous DMT

Exploring DMT: Endogenous role and therapeutic potential

N,N-Dimethyltryptamine (DMT) is a naturally occurring amine and psychedelic compound, found in plants, animals, and humans. While initial studies reported only trace amounts of DMT in mammalian brains, recent findings have identified alternative methylation pathways and DMT levels comparable to classical neurotransmitters in rodent brains, calling for a re-evaluation of its biological role and exploration of this inconsistency. This study evaluated DMT's biosynthetic pathways, focusing on indolethylamine N-methyltransferase (INMT) and its isoforms, and possible regulatory mechanisms, including alternative routes of synthesis and how physiological conditions, such as stress and hypoxia influence DMT levels. This review considers the impact of endogenous regulatory factors on DMT synthesis and degradation, particularly under conditions affecting monoamine oxidase (MAO) efficiency and activity. We also examined DMT's potential roles in various physiological processes, including neuroplasticity and neurogenesis, mitochondrial homeostasis, immunomodulation, and protection against hypoxia and oxidative stress. DMT's lipophilic properties allow it to cross cell membranes and activate intracellular 5-HT2A receptors, contributing to its role in neuroplasticity. This suggests DMT may act as an endogenous ligand for intracellular receptors, highlighting its broader biological significance beyond traditional receptor pathways. The widespread evolutionary presence of DMT's biosynthetic pathways across diverse species suggests it may play essential roles in various developmental stages and cellular adaptation to environmental challenges, highlighting the neurobiological significance of DMT and its potential clinical applications. We propose further research to explore the role of endogenous DMT, particularly as a potential neurotransmitter.

Exploring Motivations, Experiences, and Consequences of Psychedelic Use in Aotearoa New Zealand

While interest in psychedelic research has recently increased globally, little is known about use in Aotearoa New Zealand. Therefore, we sought to explore motivations, features of subjective experience, and impact of use. We also aimed to explore and compare positive, typical, and worst experiences. An online survey was completed by 997 individuals who had used at least one classical psychedelic in Aotearoa New Zealand. Worst, best, and typical experiences were compared, and logistic regression analysis was used to explore predictors of positive psychological health impact. Worst experiences differed substantially from best experiences across emotional, cognitive, and relational domains, while typical experiences more closely resembled best experiences. Motivations for use changed after initial experience, and motivations associated with different experience types varied. A higher number of psychedelic use occasions, as well as therapeutic and growth-oriented motivations, were significant predictors of positive psychological health impact. Consequences of psychedelic use were mostly positive, with best psychedelic experiences resulting in the most benefit. The findings highlight the potential of psychedelic experiences for personal growth and wellbeing and emphasize the need for an open-minded approach to drug education and policy development for the minimization of harm and maximization of benefit regarding psychedelics.

An encounter with death: a comparative thematic and content analysis of naturalistic DMT experiences and the near-death experience

Introduction

Classical near-death experiences (NDEs) refer to states of disconnected consciousness characterised by a range of features occurring in the context of being close to death. Various psychedelic substances, such as N,N-dimethyltryptamine (DMT), consistently replicate NDE features and may be considered 'near-death-like experiences.' However, a systematic qualitative analysis comparing the specifics of content with the broader themes of both psychedelic and NDEs has yet to be conducted.

Methods

We report the third thematic and content analysis of the DMT experience from a naturalistic field study, focusing on themes related to death and dying. Based on 36 semi-structured interviews, this analysis is then directly compared, qualitatively and in terms of content frequency, with a novel extension of a previous thematic analysis of 34 written NDE narratives.

Results

The 'canonical NDE themes' identified across the DMT experiences included Translocation, Bright Light(s), Sense of Dying, The Void, Disembodiment, Tunnel-like Structures, Light Being-esque Entities, Deceased Family, Life Review-like, and Hyper-empathic Experiences. A total of 95% of participants reported at least one of these. Twelve 'less typical NDE motifs' were also noted. Five classical NDE features were entirely absent from DMT, while DMT exhibited an even broader array of experience features that were absent from NDEs. DMT clearly shares a more basic phenomenological structure with NDEs but shows differences in the prevalence of certain features. Furthermore, DMT did not present any immediately recognisable linear sequencing of themes. Overall, DMT is distinctly unique in its qualitative content, characterised by its more prodigious and stereotypical nature, which includes kaleidoscopic, extraterrestrial, transcultural, fluctuating, and overwhelming elements.

Discussion

When examining the comparability between DMT and NDEs at a fundamentally more nuanced level of qualitative content (as opposed to broad themes or questionnaire items), the two experiences clearly diverge. However, a minority of NDEs, which are themselves unique, do share significant content with DMT. Taken together, DMT could be considered an 'NDE-mimetic.' The weaker comparability is likely due not only to differences in context but also to the complex neural processes occurring near death, in which endogenous DMT may only play a small role. In light of this level of parallelism with NDEs, some potential clinical applications of DMT are also discussed.

Application of microarray patches for the transdermal administration of psychedelic drugs in micro-doses

Throughout history, psychedelic compounds have been used for religious, spiritual and recreational purposes. A plethora of studies have reported the use of psychedelic compounds in the treatment of various conditions, such as alcoholism, addictions, depressive state to borderline schizophrenia, personality disorder, among other mental disorders. Psychedelic microdosing, a common technique in recent years, involves the consumption of small doses of psychedelic drugs for therapeutic purposes. This study investigated the potential of hydrogel-forming microarray patches (HF-MAPs) to deliver N,N-dimethyltryptamine (DMT), 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT), and mescaline (MES) in small doses through the skin. To this purpose, HF-MAPs were prepared using poly(vinyl alcohol) (PVA) and poly(vinyl pyrrolidone) (PVP), using citric acid as the crosslinker. Two different reservoirs, containing PVP and PVA as the main components and poly(ethylene)glycol 400 (PEG400) and glycerol as plasticising agents, were used to deliver all the drugs from the HF-MAPs. Franz cells studies in excised neonatal porcine skin demonstrated that the permeation of DMT, 5-MeO-DMT and MES was better from the PEG400 reservoir, showing a permeation of 60.71 %, 59.61 % and 41.85 % respectively. Pharmacokinetic studies in rats showed that HF-MAP technology as a strategy for microdosing psychedelic compounds was also demonstrated with DMT. AUCt0-final for the HF-MAP cohort (7186 ± 1296 ng/mL*h) was significantly greater than the IM cohort (1803 ± 53.25 ng/mL*h) (p = 0.0020), with a relative bioavailability of ∼ 72 %. Considering their pharmacokinetic profile, the frequency of DMT dosing could be reduced with HF-MAP when compared to the IM route.

N, N-dimethyltryptamine (DMT) in rodent brain: Concentrations, distribution, and recent pharmacological data

Renewed interest in the clinical use of psychedelic drugs acknowledges their therapeutic effectiveness. It has also provided a changing frame of reference for older psychedelic drug study data, especially regarding concentrations of N, N-dimethyltryptamine (DMT) reported in rodent brains and recent discoveries in DMT receptor interactions in rat brain neurons and select brain areas. The mode of action of DMT in its newly defined role as a neuroplastogen, its effectiveness in treating neuropsychiatric disorders, and its binding to intracellular sigma-1 and 5HT2a receptors may define these possible roles. Recent data also show psychedelics promote neuroplasticity via activation of sigma-1 receptors associated with the endoplasmic reticulum and binding to 5-HT2a receptors predominantly related to the intracellular membrane of the Golgi apparatus in cortical neurons and the failure of DMT to occupy cell surface 5-HT2a receptors. While DMT has been proposed as the endogenous ligand for sigma-1, there is no identified ligand for intracellular 5-HT2a receptors, which serotonin cannot acquire. DMT is proposed to be the missing endogenous ligand. These data further suggest that DMT may be involved in brain development in rat pups. Brain levels of DMT have also been shown to be elevated by stress in the rat and appear to be under an inducible, adaptive, physiological regulatory system control. With DMT acting as the natural ligand for intracellular 5HT2a receptors in the Golgi, it may also explain the subjective effects observed from the administration of psychedelics in general and define some of the natural roles for DMT in particular.

Benefits and Challenges of Ultra-Fast, Short-Acting Psychedelics in the Treatment of Depression

Unlike classical antidepressants, psychedelics such as psilocybin have been shown to induce a rapid antidepressant response. In the wake of this development, interest has emerged in ultra-fast, short-acting psychedelics such as 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) and N,N-dimethyltryptamine (DMT) with the expectation that these can produce rapid antidepressant effects following an intense but brief psychedelic intervention. The current paper reviews the clinical pharmacology of 5-MeO-DMT and DMT and their potential benefits and challenges in the treatment of depression. Both compounds display affinities for a variety of monoamine receptors and transporters, but mostly so for serotonergic (5HT) receptors, including 5HT1A and 5HT2A. Early clinical trials in small samples have shown that short interventions (15-30 min) with 5-MeO-DMT and DMT are safe and well tolerated and can induce marked improvement in symptoms of depression within 24 hours that sustain for at least 1 week. Data on long-term efficacy are currently scarce but do suggest a prolongation of the treatment response. Potential benefits of these treatments include flexible, single day dosing regimens, achievement of treatment efficacy independent from integrative therapy, and ease of clinical implementation. Future challenges include establishing the duration of the antidepressant effect and strategies on how to sustain the antidepressant response, optimization of treatment delivery parameters, and a mechanistic understanding of the clinical response. Acceptance of ultra-fast, short-acting psychedelics will depend on future randomized, placebo-controlled trials with a focus on replication, duration and maintenance of antidepressant efficacy in large patient samples.

Pharmacokinetics and pharmacodynamics of an innovative psychedelic N,N-dimethyltryptamine/harmine formulation in healthy participants: a randomized controlled trial

BACKGROUND

Recent interest in the clinical use of psychedelics has highlighted plant-derived medicines like ayahuasca showing rapid-acting and sustainable therapeutic effects in various psychiatric conditions. This traditional Amazonian plant decoction contains N,N-dimethyltryptamine (DMT) and β-carboline alkaloids such as harmine. However, its use is often accompanied by distressing effects like nausea, vomiting, and intense hallucinations, possibly due to complex pharmacokinetic/pharmacodynamic (PK-PD) interactions and lack of dose standardization.

METHODS

This study addresses these limitations by testing a novel pharmaceutical formulation containing pure forms of DMT and harmine in a double-blind, randomized, placebo-controlled trial with 31 healthy male volunteers. We evaluated PK-PD by monitoring drug and metabolite plasma levels, subjective effects, adverse events, and cardiovascular parameters. Each participant received 3 randomized treatments: (1) 100 mg buccal harmine with 100 mg intranasal DMT, (2) 100 mg buccal harmine with intranasal placebo, and (3) full placebo, using a repeated-intermittent dosing scheme, such that 10 mg of DMT (or placebo) was administered every 15 minutes.

RESULTS

N,N-dimethyltryptamine produced consistent PK profiles with Cmax values of 22.1 ng/mL and acute drug effects resembling the psychological effects of ayahuasca with a duration of 2-3 hours. Likewise, buccal harmine produced sustained-release PK profiles with Cmax values of 32.5 ng/mL but lacked distinguishable subjective effects compared to placebo. All drug conditions were safe and well tolerated, indicating the formulation's suitability for clinical applications.

CONCLUSIONS

This study underscores the potential of a patient-oriented pharmaceutical formulation of DMT and harmine to reduce risks and improve therapeutic outcomes in treating mental health disorders.

CLINICAL TRIAL REGISTRATION NUMBER

Neurodynamics of prosocial emotional processing following serotonergic stimulation with N,N-dimethyltryptamine (DMT) and harmine in healthy subjects (NCT04716335) https://clinicaltrials.gov/ct2/show/NCT04716335.

Neurobiological research on N,N-dimethyltryptamine (DMT) and its potentiation by monoamine oxidase (MAO) inhibition: from ayahuasca to synthetic combinations of DMT and MAO inhibitors

The potent hallucinogen N,N-dimethyltryptamine (DMT) has garnered significant interest in recent years due to its profound effects on consciousness and its therapeutic psychopotential. DMT is an integral (but not exclusive) psychoactive alkaloid in the Amazonian plant-based brew ayahuasca, in which admixture of several β-carboline monoamine oxidase A (MAO-A) inhibitors potentiate the activity of oral DMT, while possibly contributing in other respects to the complex psychopharmacology of ayahuasca. Irrespective of the route of administration, DMT alters perception, mood, and cognition, presumably through agonism at serotonin (5-HT) 1A/2A/2C receptors in brain, with additional actions at other receptor types possibly contributing to its overall psychoactive effects. Due to rapid first pass metabolism, DMT is nearly inactive orally, but co-administration with β-carbolines or synthetic MAO-A inhibitors (MAOIs) greatly increase its bioavailability and duration of action. The synergistic effects of DMT and MAOIs in ayahuasca or synthetic formulations may promote neuroplasticity, which presumably underlies their promising therapeutic efficacy in clinical trials for neuropsychiatric disorders, including depression, addiction, and post-traumatic stress disorder. Advances in neuroimaging techniques are elucidating the neural correlates of DMT-induced altered states of consciousness, revealing alterations in brain activity, functional connectivity, and network dynamics. In this comprehensive narrative review, we present a synthesis of current knowledge on the pharmacology and neuroscience of DMT, β-carbolines, and ayahuasca, which should inform future research aiming to harness their full therapeutic potential.

Ayahuasca-enhanced extinction of fear behaviour: Role of infralimbic cortex 5-HT2A and 5-HT1A receptors

BACKGROUND AND PURPOSE

Ayahuasca (AYA) is a botanical psychedelic with promising results in observational and small clinical trials for depression, trauma and drug use disorders. Its psychoactive effects primarily stem from N,N-dimethyltryptamine (DMT). However, there is a lack of research on how and where AYA acts in the brain. This study addressed these questions by examining the extinction of aversive memories in AYA-treated rats.

EXPERIMENTAL APPROACH

We focused on the 5-HT1A and 5-HT2A receptors, as DMT exhibits a high affinity for both of them, along with the infralimbic cortex in which activity and plasticity play crucial roles in regulating the mnemonic process under analysis.

KEY RESULTS

A single oral treatment with AYA containing 0.3 mg·kg-1 of DMT increased the within-session extinction of contextual freezing behaviour without affecting its recall. This protocol, when repeated twice on consecutive days, enhanced extinction recall. These effects were consistent for both 1- and 21-day-old memories in males and females. AYA effects on fear extinction were independent of changes in anxiety and general exploratory activity: AYA- and vehicle-treated animals showed no differences when tested in the elevated plus-maze. The 5-HT2A receptor antagonist MDL-11,939 and the 5-HT1A receptor antagonist WAY-100635 infused into the infralimbic cortex respectively blocked within- and between-session fear extinction effects resulting from repeated oral administration of AYA.

CONCLUSION AND IMPLICATIONS

Our findings highlight complementary mechanisms by which AYA facilitates the behavioural suppression of aversive memories in the rat infralimbic cortex. These results suggest potential beneficial effects of AYA or DMT in stress-related disorders.

N, N-Dimethyltryptamine, a natural hallucinogen, ameliorates Alzheimer's disease by restoring neuronal Sigma-1 receptor-mediated endoplasmic reticulum-mitochondria crosstalk

BACKGROUND

Aberrant neuronal Sigma-1 receptor (Sig-1r)-mediated endoplasmic reticulum (ER)- mitochondria signaling plays a key role in the neuronal cytopathology of Alzheimer's disease (AD). The natural psychedelic N, N-dimethyltryptamine (DMT) is a Sig-1r agonist that may have the anti-AD potential through protecting neuronal ER-mitochondrial interplay.

METHODS

3×TG-AD transgenic mice were administered with chronic DMT (2 mg/kg) for 3 weeks and then performed water maze test. The Aβ accumulation in the mice brain were determined. The Sig-1r level upon DMT treatment was tested. The effect of DMT on the ER-mitochondrial contacts site and multiple mitochondria-associated membrane (MAM)-associated proteins were examined. The effect of DMT on calcium transport between ER and mitochondria and the mitochondrial function were also evaluated.

RESULTS

chronic DMT (2 mg/kg) markedly alleviated cognitive impairment of 3×TG-AD mice. In parallel, it largely diminished Aβ accumulation in the hippocampus and prefrontal cortex. DMT restored the decreased Sig-1r levels of 3×TG-AD transgenic mice. The hallucinogen reinstated the expression of multiple MAM-associated proteins in the brain of 3×TG-AD mice. DMT also prevented physical contact and calcium dynamic between the two organelles in in vitro and in vivo pathological circumstances. DMT modulated oxidative phosphorylation (OXPHOS) and ATP synthase in the in vitro model of AD.

CONCLUSION

The anti-AD effects of DMT are associated with its protection of neuronal ER-mitochondria crosstalk via the activation of Sig-1r. DMT has the potential to serve as a novel preventive and therapeutic agent against AD.

Spectroscopic behavior of bufotenine and bufotenine N-oxide: Solvent and pH effects and interaction with biomembrane models

Bufotenine is a fluorescent analog of Dimethyltryptamine (DMT) that has been widely studied due to its psychedelic properties and biological activity. However, little is known about its spectroscopic properties in different media. Thus, we present in this work, for the first time, the spectroscopic behavior of bufotenine and bufotenine N-oxide by means of their fluorescence properties. Both molecules exhibit changes in optical absorption and emission spectra with variations in pH of the medium and in different solvents. Assays in the presence of biomembranes models, like micelles and liposomes, were also performed. In surfactants titration experiments, the spectral shift observed in fluorescence shows the interaction of both molecules with pre-micellar structures and with micelles. Steady state anisotropy measurements show that both bufotenine and bufotenine N-oxide, in the studied concentration range, interact with liposomes without causing changes in the fluidity of the lipid bilayer. These results can be useful in studies that aim at searching for new compounds, inspired by bufotenine and bufotenine N-oxide, with relevant pharmacological activities and also in studies that use these molecules as markers of psychiatric disorders.

Psychedelic Therapy: A Primer for Primary Care Clinicians-N,N-Dimethyltryptamine and Ayahuasca

BACKGROUND

N,N-dimethyltryptamine (DMT) is a naturally occurring serotonergic psychedelic found in natural plants around the globe. As the main psychoactive component in ayahuasca, which also contains monoamine oxidase inhibitors, DMT has been consumed as plant-based brew by indigenous peoples for centuries. Further research is required to delineate the therapeutic utility of DMT.

AREAS OF UNCERTAINTY

Although previous research has shown that DMT is synthesized endogenously, it may not be produced at physiologically relevant concentrations. Additionally, the phenomenological similarities between the DMT-induced state and near-death experiences led to the popular hypothesis that endogenous DMT is released during the dying process. However, this hypothesis continues to be debated. Generally, DMT and ayahuasca seem to be physiologically and psychiatrically safe, although ayahuasca is known to cause transient vomiting.

THERAPEUTIC ADVANCES

A double-blind, randomized controlled trial showed that, within 1 week, ayahuasca causes remission in 36% of patients with treatment-resistant depression. According to top-line results from a recent phase IIa trial, 57% of patients with major depressive disorder experienced remission 12 weeks after receiving a single intravenous dose of DMT.

LIMITATIONS

There has only been a single published double-blind randomized controlled trial on ayahuasca and 2 on DMT. All clinical trials have had small sample sizes (≤34 participants). DMT requires further research to understand its therapeutic and clinical potential as a psychedelic.

CONCLUSIONS

Preliminary evidence indicates that ayahuasca and DMT may be more effective than existing antidepressants for treating major depressive disorder and treatment-resistant depression.

The changing outlook of psychedelic drugs: The importance of risk assessment and occupational exposure limits

Serotonergic psychedelics, such as lysergic acid diethylamide (LSD), psilocybin, dimethyltryptamine (DMT), and 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT), are currently being investigated for the treatment of psychiatric disorders such as depression and anxiety. Clinical trials with psilocybin and LSD have shown improvement in emotional and psychological scores. Although these drugs are reported to be safe in a controlled environment (such as clinical trials), exposure to low doses of these drugs can result in psychedelic effects, and therefore, occupational safety is an important consideration to prevent adverse effects in the workplace from low daily exposure. This article will discuss the factors involved in the derivation of occupational exposure limits (OELs) and risk assessment of these psychedelic drugs. To support the OEL derivations of psychedelic drugs, information regarding their mechanism of action, adverse effect profiles, pharmacokinetics, clinical effects, and nonclinical toxicity were considered. Additionally, psilocybin and LSD, which are the most extensively researched psychedelic substances, are employed as illustrative examples in case studies. The OELs derived for psilocybin and for LSD are 0.05 and 0.002 μg/m3 , respectively, which indicates that these are highly hazardous compounds, and it is important to take into account suitable safety measures and risk-management strategies in order to minimize workplace exposure.

Is there an affective neuroscience of spirituality? The development and validation of the OCEANic feelings scale

Background

Oceanic feelings represent a phenomenological structure of affective sensations that characteristically involve feelings of self-dissolution and feelings of unity and transcendence. This study presents the preliminary version of a self-report instrument to measure individual dispositions toward oceanic feelings in order to enable further research within the concept of primary emotions postulated by Jaak Panksepp.

Methods

A first version of the questionnaire was applied to a total sample of 926 German-speaking adults of the general population. After performing item analysis and principal component analysis (PCA) in a first study (N = 300), the questionnaire was shortened. In a second study (N = 626), confirmatory factor analysis (CFA) was conducted and emerged scales were related to the already established instruments for the assessment of primary emotions (BANPS-GL) and Big Five personality traits (BFI-44).

Results

The OCEANic scale exhibited reliabilities ranging from Cronbach's α = 0.82 (positive) to α = 0.88 (negative) and plausible correlations with behavioral traits related to the seven affective neurobiological systems (ANGER, FEAR, CARE, SEEK, PLAY, SADNESS, and LUST) as well as with personality factors measured by the Big Five Inventory. For CFA, a bifactorial model with an overall factor demonstrated good fit: RMSEA = 0.00 (90% CI:0.00, 0.03); TLI = 1.00; CFI = 1.00; NFI = 0.99.

Discussion

The OCEANic scale enables the operationalization of oceanic feelings comprising two subscales and one total scale. The results indicate good reliability and acceptable factorial validity. Establishment and further validation of the OCEANic scale within future research will be needed to fully understand the role of oceanic feelings within the human affective life, especially the personality trait of spirituality.

Potential therapeutic effects of an ayahuasca-inspired N,N-DMT and harmine formulation: a controlled trial in healthy subjects

Background

There is growing scientific evidence for the therapeutic benefits of the Amazonian plant-based psychedelic "ayahuasca" for neuropsychiatric disorders such as depression and anxiety. However, there are certain challenges when incorporating botanical ayahuasca into biomedical research and clinical therapy environments. Formulations inspired by ayahuasca, which contain specific and standardized active components, are a potential remedy.

Methods

We investigated subjective acute and persisting effects of a novel formulation containing the reversible monoamine oxidase inhibitor harmine (orodispersible tablet containing 100 mg MAO-I) and N,N-dimethyltryptamine (incremental intranasal dosing of up to 100 mg DMT), compared with two other conditions, namely harmine alone and placebo, in a crossover RCT in 31 healthy male subjects.

Results

DMT + harmine, but not harmine alone, induced a psychedelic experience assessed with the 5D-ASC rating scale [global score: F(2,60) = 80.21, p < 0.001] and acute experience sampling items over time, characterized by psychological insights [PIQ, F(2,58.5) = 28.514, p < 0.001], emotional breakthroughs [EBI, F(2,60) = 26.509, p < 0.001], and low scores on the challenging experience questionnaire [CEQ, F(2,60) = 12.84, p < 0.001]. Participants attributed personal and spiritual significance to the experience (GSR) with mainly positive persisting effects (PEQ) at 1- and 4-months follow-up. Acute drug effects correlated positively with persisting effects. We found no changes in trait measures of personality, psychological flexibility, or general well-being, and no increases in psychopathology (SCL-90-R) were reported.

Discussion and Conclusion

Our results suggest that the experience induced by the standardized DMT + harmine formulation induces a phenomenologically rich psychedelic experience, demonstrates good psychological safety and tolerability, is well tolerated, and induces beneficial psychological processes that could possibly support psychotherapy. Further studies are required to investigate the psychotherapeutic potential in patients.

Overcoming the clinical challenges of traditional ayahuasca: a first-in-human trial exploring novel routes of administration of N,N-Dimethyltryptamine and harmine

Recently, the Amazonian plant medicine "ayahuasca"-containing the psychedelic compound N,N-dimethyltryptamine (DMT) and numerous β-carboline alkaloids, such as harmine-has been suggested to exhibit beneficial effects in patients with affective and other mental health disorders. Although ayahuasca ingestion is considered safe, its pharmacokinetics/pharmacodynamics and tolerability profile pose some challenges and may limit the clinical applicability in vulnerable patient populations. While overdosing and the admixture of intolerable plant constituents may explain some of the common adverse reactions, the peroral route of administration may represent another relevant source of gastro-intestinal intolerabilities and unpredictable pharmacokinetics across users. To overcome these challenges, the present work aimed at creating ayahuasca-analogue formulations with improved pharmacokinetics and tolerability profiles. To this end, we developed peroral formulas and compared them with parenteral formulas specifically designed to circumvent the gastro-intestinal tract. In more detail, peroral administration of a capsule (containing purified DMT and harmine) was tested against a combined administration of an oromucosal harmine tablet and an intranasal DMT spray at two dose levels in an open-label within-subject study in 10 healthy male subjects. Pharmacokinetic and pharmacodynamic profiles were assessed by means of continuous blood sampling, vital sign monitoring, and psychometric assessments. Common side effects induced by traditional herbal ayahuasca such as nausea, vomiting, and diarrhea were significantly attenuated by our DMT/harmine formulations. While all preparations were well tolerated, the combined buccal/intranasal administration of harmine and DMT yielded substantially improved pharmacokinetic profiles, indicated by significantly reduced variations in systemic exposure. In conclusion, the combined buccal/intranasal administration of harmine and DMT is an innovative approach that may pave the way towards a safe, rapid-acting, and patient-oriented administration of DMT/harmine for the treatment of affective disorders. Clinical Trial Registration: clinicaltrials.gov, identifier NCT04716335.

Exploring the Potential Utility of Psychedelic Therapy for Patients With Amyotrophic Lateral Sclerosis

Background: Amyotrophic lateral sclerosis (ALS) is an aggressive, terminal neurodegenerative disease that causes death of motor neurons and has an average survival time of 3-4 years. ALS is the most common motor neuron degenerative disease and is increasing in prevalence. There is a pressing need for more effective ALS treatments as available pharmacotherapies do not reverse disease progression or provide substantial clinical benefit. Furthermore, despite psychological distress being highly prevalent in ALS patients, psychological treatments remain understudied. Psychedelics (i.e., serotonergic psychedelics and related compounds like ketamine) have seen a resurgence of research into therapeutic applications for treating a multitude of neuropsychiatric conditions, including psychiatric and existential distress in life-threatening illnesses. Methods: We conducted a narrative review to examine the potential of psychedelic assisted-psychotherapy (PAP) to alleviate psychiatric and psychospiritual distress in ALS. We also discussed the safety of using psychedelics in this population and proposed putative neurobiological mechanisms that may therapeutically intervene on ALS neuropathology. Results: PAP has the potential to treat psychological dimensions and may also intervene on neuropathological dimensions of ALS. Robust improvements in psychiatric and psychospiritual distress from PAP in other populations provide a strong rationale for utilizing this therapy to treat ALS-related psychiatric and existential distress. Furthermore, relevant neuroprotective properties of psychedelics warrant future preclinical trials to investigate this area in ALS models. Conclusion: PAP has the potential to serve as an effective treatment in ALS. Given the lack of effective treatment options, researchers should rigorously explore this therapy for ALS in future trials.

The risk of chronic psychedelic and MDMA microdosing for valvular heart disease

Psychedelic microdosing is the practice of taking very low doses of psychedelic substances, typically over a longer period of time. The long-term safety of chronic microdosing is relatively uncharacterized, but valvular heart disease (VHD) has been proposed as a potential risk due to activation of the serotonin 5-HT2B receptor. However, this risk has not yet been comprehensively assessed. This analysis searched for all relevant in vitro, animal, and clinical studies related to the VHD risk of lysergic acid diethylamide (LSD), psilocybin, mescaline, N,N-dimethyltryptamine (DMT), and the non-psychedelic 3,4-methylenedioxymethamphetamine (MDMA). All five compounds and some metabolites could bind to the 5-HT2B receptor with potency equal to or greater than that of the 5-HT2A receptor, the primary target of psychedelics. All compounds were partial agonists at the 5-HT2B receptor with the exception of mescaline, which could not be adequately assessed due to low potency. Safety margins relative to the maximum plasma concentrations from typical microdoses were greater than known valvulopathogens, but not without potential risk. No animal or clinical studies appropriately designed to evaluate VHD risk were found for the four psychedelics. However, there is some clinical evidence that chronic ingestion of full doses of MDMA is associated with VHD. We conclude that VHD is a potential risk with chronic psychedelic microdosing, but further studies are necessary to better define this risk.

Ligand-Free Signaling of G-Protein-Coupled Receptors: Physiology, Pharmacology, and Genetics

G-protein-coupled receptors (GPCRs) are ubiquitous sensors and regulators of cellular functions. Each GPCR exists in complex aggregates with multiple resting and active conformations. Designed to detect weak stimuli, GPCRs can also activate spontaneously, resulting in basal ligand-free signaling. Agonists trigger a cascade of events leading to an activated agonist-receptor G-protein complex with high agonist affinity. However, the ensuing signaling process can further remodel the receptor complex to reduce agonist affinity, causing rapid ligand dissociation. The acutely activated ligand-free receptor can continue signaling, as proposed for rhodopsin and μ opioid receptors, resulting in robust receptor activation at low agonist occupancy with enhanced agonist potency. Continued receptor stimulation can further modify the receptor complex, regulating sustained ligand-free signaling-proposed to play a role in opioid dependence. Basal, acutely agonist-triggered, and sustained elevated ligand-free signaling could each have distinct functions, reflecting multi-state conformations of GPCRs. This review addresses basal and stimulus-activated ligand-free signaling, its regulation, genetic factors, and pharmacological implications, focusing on opioid and serotonin receptors, and the growth hormone secretagogue receptor (GHSR). The hypothesis is proposed that ligand-free signaling of 5-HT2A receptors mediate therapeutic effects of psychedelic drugs. Research avenues are suggested to close the gaps in our knowledge of ligand-free GPCR signaling.

Classic psychedelics do not affect T cell and monocyte immune responses

INTRODUCTION

Classic psychedelics have been shown to exert therapeutic potential for the treatment of various psychiatric disorders, neuropsychiatric diseases, and neuronal damage. Besides their psychopharmacological activity, psychedelics have been reported to modulate immune functions. There has thus far been a sparse exploration of the direct immune-modulating effect of psychedelics on human immune cells in vitro. Since T cells are key mediators of several immune functions, inhibition of their function would increase the risk of infections.

METHODS

We investigated the effect of the classic psychedelics lysergic acid diethylamide (LSD), psilocin, N,N-dimethyltryptamine (DMT), and mescaline on the proliferation and stimulated cytokine release of primary human T lymphocytes and on the stimulated NF-κB induction of monocytes.

RESULTS

We did not observe any relevant direct immune-modulatory effects of the tested classic psychedelics in either cell line.

DISCUSSION

We concluded that LSD, psilocin, DMT, or mescaline did not directly stimulate the proliferation or cytokine secretion of primary human T lymphocytes or stimulate NF-κB induction of monocytes. Our findings support the future safe use of classic psychedelics in assisted psychotherapy in patients with life-threatening diseases where immune suppression and diminished immune function would be detrimental.

The complete organellar genomes of the entheogenic plant Psychotria viridis (Rubiaceae), a main component of the ayahuasca brew

Psychotria viridis (Rubioideae: Rubiaceae), popularly known as chacrona, is commonly found as a shrub in the Amazon region and is well-known to produce psychoactive compounds, such as the N,N-dimethyltryptamine (DMT). Together with the liana Banisteropsis caapi, P. viridis is one of the main components of the Amerindian traditional, entheogenic beverage known as ayahuasca. In this work, we assembled and annotated the organellar genomes (ptDNA and mtDNA), presenting the first genomics resources for this species. The P. viridis ptDNA exhibits 154,106 bp, encoding all known ptDNA gene repertoire found in angiosperms. The Psychotria genus is a complex paraphyletic group, and according to phylogenomic analyses, P. viridis is nested in the Psychotrieae clade. Comparative ptDNA analyses indicate that most Rubiaceae plastomes present conserved ptDNA structures, often showing slight differences at the junction sites of the major four regions (LSC-IR-SSC). For the mitochondrion, assembly graph-based analysis supports a complex mtDNA organization, presenting at least two alternative and circular mitogenomes structures exhibiting two main repeats spanning 24 kb and 749 bp that may symmetrically isomerize the mitogenome into variable arrangements and isoforms. The circular mtDNA sequences (615,370 and 570,344 bp) encode almost all plant mitochondrial genes (except for the ccmC, rps7, rps10, rps14, rps19, rpl2 and rpl16 that appears as pseudogenes, and the absent genes sdh3, rps2, rsp4, rsp8, rps11, rpl6, and rpl10), showing slight variations related to exclusive regions, ptDNA integration, and relics of previous events of LTR-RT integration. The detection of two mitogenomes haplotypes is evidence of heteroplasmy as observed by the complex organization of the mitochondrial genome using graph-based analysis. Taken together, these results elicit the primary insights into the genome biology and evolutionary history of Psychotria viridis and may be used to aid strategies for conservation of this sacred, entheogenic species.

New Paradigms of Old Psychedelics in Schizophrenia

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-HT_2A 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-HT_2A 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 5HT_2A, 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.