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Quantum chemical (QM:MM) investigation of the mechanism of enzymatic reaction of tryptamine and N,N-dimethyltryptamine with monoamine oxidase A

January 3, 2022 / DMT, Papers, Pharmacology & Chemistry / Leave a Comment / By / ,

Abstract

The endogenous psychedelic (mind-altering) N,N-dimethyltryptamine (DMT) molecule has an important role in tissue protection, regeneration, and immunity via sigma-1 receptor activation as its natural ligand. The immunologic properties of DMT suggest this biogenic compound should be investigated thoroughly in other aspects as well. In our in silico project, we examined the metabolism of DMT and its primary analogue, the tryptamine (T), by the monoamine oxidase (MAO) flavoenzyme. MAO has two isoforms, MAO-A and MAO-B. MAOs perform the oxidation of various monoamines by their flavin adenine dinucleotide (FAD) cofactor. Two-layer QM:MM calculations at the ONIOM(M06-2X/6-31++G(d,p):UFF=QEq) level were performed including the whole enzyme to explore the potential energy surface (PES) of the reactions. Our findings reinforced that a hybrid mechanism, a mixture of pure H+ and H– transfer pathways, describes precisely the rate-determining step of amine oxidation as suggested by earlier works. Additionally, our results show that the oxidation of tertiary amine DMT requires a lower activation barrier than the primary amine T. This may reflect a general rule, thus we recommend further investigations. Furthermore, we demonstrated that at pH 7.4 the protonated form of these substrates enter the enzyme. As the deprotonation of substrates is crucial, we presumed protonated cofactor, FADH+, may form. Surprisingly, the activation barriers are much lower compared to FAD with both substrates. Therefore, we suggest further investigations in this direction.

Kubicskó, K., , & Farkas, Ö., (2020). Quantum chemical (QM:MM) investigation of the mechanism of enzymatic reaction of tryptamine and N,N-dimethyltryptamine with monoamine oxidase A. Organic & biomolecular chemistry, 18(47), 9660–9674. https://doi.org/10.1039/d0ob01118e

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MDMA-induced changes in within-network connectivity contradict the specificity of these alterations for the effects of serotonergic hallucinogens

January 7, 2022 / MDMA, Neuroscience, Papers / Leave a Comment / By / , , , , , , ,

Abstract

It has been reported that serotonergic hallucinogens like lysergic acid diethylamide (LSD) induce decreases in functional connectivity within various resting-state networks. These alterations were seen as reflecting specific neuronal effects of hallucinogens and it was speculated that these shifts in connectivity underlie the characteristic subjective drug effects. In this study, we test the hypothesis that these alterations are not specific for hallucinogens but that they can be induced by monoaminergic stimulation using the non-hallucinogenic serotonin-norepinephrine-dopamine releasing agent 3,4-methylenedioxymethamphetamine (MDMA). In a randomized, placebo-controlled, double-blind, crossover design, 45 healthy participants underwent functional magnetic resonance imaging (fMRI) following oral administration of 125 mg MDMA. The networks under question were identified using independent component analysis (ICA) and were tested with regard to within-network connectivity. Results revealed decreased connectivity within two visual networks, the default mode network (DMN), and the sensorimotor network. These findings were almost identical to the results previously reported for hallucinogenic drugs. Therefore, our results suggest that monoaminergic substances can induce widespread changes in within-network connectivity in the absence of marked subjective drug effects. This contradicts the notion that these alterations can be regarded as specific for serotonergic hallucinogens. However, changes within the DMN might explain antidepressants effects of some of these substances.

Müller, F., Holze, F., Dolder, P., Ley, L., Vizeli, P., Soltermann, A., Liechti, M. E., & Borgwardt, S. (2021). MDMA-induced changes in within-network connectivity contradict the specificity of these alterations for the effects of serotonergic hallucinogens. Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology, 46(3), 545–553. https://doi.org/10.1038/s41386-020-00906-2

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The time course of psychotic symptom side effects of ketamine in the treatment of depressive disorders: a systematic review and meta-analysis

January 3, 2022 / Depressive Disorders, Ketamine, Papers / Leave a Comment / By / , , , ,

Abstract

Objective: Ketamine is a potential rapid-acting treatment for depression. Studies have suggested that the side effects are minimal and temporary, but the psychotic symptom side effects have yet to be fully examined. This study investigated whether ketamine infusion in the treatment of mood disorders is associated with increases in positive symptoms and whether these symptom effects endure over time.

Methods: A systematic review and meta-analysis of studies of ketamine in the treatment of depression. Embase and Medline databases were searched for studies including (a) participants with major affective disorders, (b) 0.4 or 0.5 mg intravenously administered ketamine, (c) measurement of positive symptoms using BPRS+, and (d) a within-subject repeated-measures design with participants serving as their own baseline.

Results: Seventeen studies met the inclusion criteria, comprising 458 participants. The meta-analyses examined symptom change occurring within the first 4 h, after 1 day, and after 3 days. Results showed significant BPRS+ increases within the first 30-60 min in 72% of studies, followed by a return to baseline levels.

Conclusion: Peak symptom change occurred within the first hour post infusion. There are limited data to determine if ketamine is safe in the longer term, but there were no indications that psychotic symptoms re-occurred after the first hour and in the days following administration.

Tashakkori, M., Ford, A., Dragovic, M., Gabriel, L., & Waters, F. (2021). The time course of psychotic symptom side effects of ketamine in the treatment of depressive disorders: a systematic review and meta-analysis. Australasian psychiatry : bulletin of Royal Australian and New Zealand College of Psychiatrists, 29(1), 80–87. https://doi.org/10.1177/1039856220961642

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Time is of the essence: Coupling sleep-wake and circadian neurobiology to the antidepressant effects of ketamine

January 3, 2022 / Depressive Disorders, Ketamine, Papers / Leave a Comment / By / , , , ,

Abstract

Several studies have demonstrated the effectiveness of ketamine in rapidly alleviating depression and suicidal ideation. Intense research efforts have been undertaken to expose the precise mechanism underlying the antidepressant action of ketamine; however, the translation of findings into new clinical treatments has been slow. This translational gap is partially explained by a lack of understanding of the function of time and circadian timing in the complex neurobiology around ketamine. Indeed, the acute pharmacological effects of a single ketamine treatment last for only a few hours, whereas the antidepressant effects peak at around 24 hours and are sustained for the following few days. Numerous studies have investigated the acute and long-lasting neurobiological changes induced by ketamine; however, the most dramatic and fundamental change that the brain undergoes each day is rarely taken into consideration. Here, we explore the link between sleep and circadian regulation and rapid-acting antidepressant effects and summarize how diverse phenomena associated with ketamine’s antidepressant actions – such as cortical excitation, synaptogenesis, and involved molecular determinants – are intimately connected with the neurobiology of wake, sleep, and circadian rhythms. We review several recently proposed hypotheses about rapid antidepressant actions, which focus on sleep or circadian regulation, and discuss their implications for ongoing research. Considering these aspects may be the last piece of the puzzle necessary to gain a more comprehensive understanding of the effects of rapid-acting antidepressants on the brain.

Kohtala, S., Alitalo, O., Rosenholm, M., Rozov, S., & Rantamäki, T. (2021). Time is of the essence: Coupling sleep-wake and circadian neurobiology to the antidepressant effects of ketamine. Pharmacology & therapeutics, 221, 107741. https://doi.org/10.1016/j.pharmthera.2020.107741

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Exploratory Controlled Study of the Migraine-Suppressing Effects of Psilocybin

January 3, 2022 / Headache Pain and Neurological Disorders, Mushrooms / Psilocybin, Papers / Leave a Comment / By / , , , , , , , ,

Abstract

While anecdotal evidence suggests that select 5-hydroxytryptamine 2A (5-HT2A) receptor ligands, including psilocybin, may have long-lasting therapeutic effects after limited dosing in headache disorders, controlled investigations are lacking. In an exploratory double-blind, placebo-controlled, cross-over study, adults with migraine received oral placebo and psilocybin (0.143 mg/kg) in 2 test sessions spaced 2 weeks apart. Subjects maintained headache diaries starting 2 weeks before the first session until 2 weeks after the second session. Physiological and psychological drug effects were monitored during sessions and several follow-up contacts with subjects were carried out to assure safety of study procedures. Ten subjects were included in the final analysis. Over the 2-week period measured after single administration, the reduction in weekly migraine days from baseline was significantly greater after psilocybin (mean, – 1.65 (95% CI: – 2.53 to – 0.77) days/week) than after placebo (- 0.15 (- 1.13 to 0.83) days/week; p = 0.003, t(9) = 4.11). Changes in migraine frequency in the 2 weeks after psilocybin were not correlated with the intensity of acute psychotropic effects during drug administration. Psilocybin was well-tolerated; there were no unexpected or serious adverse events or withdrawals due to adverse events. This exploratory study suggests there is an enduring therapeutic effect in migraine headache after a single administration of psilocybin. The separation of acute psychotropic effects and lasting therapeutic effects is an important finding, urging further investigation into the mechanism underlying the clinical effects of select 5-HT2A receptor compounds in migraine, as well as other neuropsychiatric conditions. Clinicaltrials.gov : NCT03341689.

Schindler, E., Sewell, R. A., Gottschalk, C. H., Luddy, C., Flynn, L. T., Lindsey, H., Pittman, B. P., Cozzi, N. V., & D’Souza, D. C. (2021). Exploratory Controlled Study of the Migraine-Suppressing Effects of Psilocybin. Neurotherapeutics : the journal of the American Society for Experimental NeuroTherapeutics, 18(1), 534–543. https://doi.org/10.1007/s13311-020-00962-y

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Ketamine in Bipolar Disorder: A Review

January 6, 2022 / Depressive Disorders, Ketamine, Papers / Leave a Comment / By / , ,

Abstract

Bipolar disorder (BD) is a psychiatric illness associated with high morbidity, mortality and suicide rate. It has neuroprogressive course and a high rate of treatment resistance. Hence, there is an unquestionable need for new BD treatment strategies. Ketamine appears to have rapid antidepressive and antisuicidal effects. Since most of the available studies concern unipolar depression, here we present a novel insight arguing that ketamine might be a promising treatment for bipolar disorder.

Wilkowska, A., Szałach, Ł., & Cubała, W. J. (2020). Ketamine in Bipolar Disorder: A Review. Neuropsychiatric disease and treatment, 16, 2707–2717. https://doi.org/10.2147/NDT.S282208

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Pivotal mental states

January 3, 2022 / Papers, Psychology / Leave a Comment / By / ,

Abstract

This paper introduces a new construct, the ‘pivotal mental state’, which is defined as a hyper-plastic state aiding rapid and deep learning that can mediate psychological transformation. We believe this new construct bears relevance to a broad range of psychological and psychiatric phenomena. We argue that pivotal mental states serve an important evolutionary function, that is, to aid psychological transformation when actual or perceived environmental pressures demand this. We cite evidence that chronic stress and neurotic traits are primers for a pivotal mental state, whereas acute stress can be a trigger. Inspired by research with serotonin 2A receptor agonist psychedelics, we highlight how activity at this particular receptor can robustly and reliably induce pivotal mental states, but we argue that the capacity for pivotal mental states is an inherent property of the human brain itself. Moreover, we hypothesize that serotonergic psychedelics hijack a system that has evolved to mediate rapid and deep learning when its need is sensed. We cite a breadth of evidences linking stress via a variety of inducers, with an upregulated serotonin 2A receptor system (e.g. upregulated availability of and/or binding to the receptor) and acute stress with 5-HT release, which we argue can activate this primed system to induce a pivotal mental state. The pivotal mental state model is multi-level, linking a specific molecular gateway (increased serotonin 2A receptor signaling) with the inception of a hyper-plastic brain and mind state, enhanced rate of associative learning and the potential mediation of a psychological transformation.

Brouwer, A., & Carhart-Harris, R. L. (2021). Pivotal mental states. Journal of psychopharmacology (Oxford, England), 35(4), 319–352. https://doi.org/10.1177/0269881120959637

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DARK Classics in Chemical Neuroscience: Salvinorin A

January 3, 2022 / Neuroscience, Papers, Pharmacology & Chemistry, Salvia / Salvinorin A / Leave a Comment / By / , , ,

Abstract

Salvinorin A is the main bioactive compound in Salvia divinorum, an endemic plant with ancestral use by the inhabitants of the Mazateca mountain range (Sierra Mazateca) in Oaxaca, México. The main use of la pastora, as locally known, is in spiritual rites due to its extraordinary hallucinogenic effects. Being the first known nonalkaloidal opioid-mediated psychotropic molecule, salvinorin A set new research areas in neuroscience. The absence of a protonated amine group, common to all previously known opioids, results in a fast metabolism with the concomitant fast elimination and swift loss of activity. The worldwide spread and psychotropic effects of salvinorin A account for its misuse and classification as a drug of abuse. Consequently, salvinorin A and Salvia divinorum are now banned in many countries. Several synthetic efforts have been focused on the improvement of physicochemical and biological properties of salvinorin A: from total synthesis to hundreds of analogues. In this Review, we discuss the impact of salvinorin A in chemistry and neuroscience covering the historical relevance, isolation from natural sources, synthetic efforts, and pharmacological and safety profiles. Altogether, the chemistry behind and the taboo that encloses salvinorin A makes it one of the most exquisite naturally occurring drugs.

Hernández-Alvarado, R. B., Madariaga-Mazón, A., Ortega, A., & Martinez-Mayorga, K. (2020). DARK Classics in Chemical Neuroscience: Salvinorin A. ACS chemical neuroscience, 10.1021/acschemneuro.0c00608. Advance online publication. https://doi.org/10.1021/acschemneuro.0c00608

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The potential use of N-methyl-3,4-methylenedioxyamphetamine (MDMA) assisted psychotherapy in the treatment of eating disorders comorbid with PTSD

January 6, 2022 / Anxiety Disorders / PTSD, Eating Disorders, MDMA, Papers / Leave a Comment / By / , ,

Abstract

Despite advances in the field, eating disorders (EDs) remain very challenging disorders to treat, especially when comorbid with posttraumatic stress disorder (PTSD). N-methyl-3,4-methylenedioxyamphetamine (MDMA)-assisted psychotherapy for treatment refractory PTSD shows great promise, with two-thirds of participants achieving full remission at 1 year or more at follow-up. PTSD is a common comorbidity associated with EDs, and patients with EDs and PTSD (ED-PTSD) are reported to have higher severities of illness, greater comorbidities, higher treatment dropouts, and poorer outcomes. We hypothesize that MDMA-assisted psychotherapy will be efficacious in the ED-PTSD population for both ED and PTSD symptoms. The rationales for and proposed mechanisms of MDMA-assisted psychotherapy for ED-PTSD are considered from neurobiological, psychological and social perspectives. MDMA is associated with unique psychopharmacological effects, including: 1) reduced fear, 2) enhanced wellbeing, 3) increased sociability/extroversion, 4) reduced self-criticism, 5) increased compassion for self/others, 6) increased interpersonal trust, and 7) alert state of consciousness. These anxiolytic and prosocial effects may counteract avoidance and hyperarousal in the context of psychotherapy for those with ED-PTSD. Other clinical features of EDs that may be amenable to MDMA-assisted psychotherapy include body image distortion, cognitive rigidity, and socio-emotional processing difficulties. To illustrate its potential, personal accounts of individuals with ED-PTSD symptoms reporting benefit from MDMA adjunctive to psychotherapy are described. In addition, the possible risks and challenges in conducting this work are addressed, and future implications of this proposal are discussed.

Brewerton, T. D., Lafrance, A., & Mithoefer, M. C. (2021). The potential use of N-methyl-3,4-methylenedioxyamphetamine (MDMA) assisted psychotherapy in the treatment of eating disorders comorbid with PTSD. Medical hypotheses, 146, 110367. https://doi.org/10.1016/j.mehy.2020.110367

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Anti-inflammatory activity of ayahuasca: therapeutical implications in neurological and psychiatric diseases

September 17, 2024 / 5-MeO-DMT, Ayahuasca, DMT, Neuroscience, Papers, Substance / Leave a Comment / By / , ,

Abstract

Ayahuasca is a decoction with psychoactive properties, used for millennia for therapeutic and religious purposes by indigenous groups and the population of amazonian countries. As described in this narrative review, it is essentially constituted by β-carbolines and tryptamines, and it has therapeutic effects on behavioral disorders due to the inhibition of the monoamine oxidase enzyme and the activation of 5-hydroxytryptamine receptors, demonstrated through preclinical and clinical studies. It was recently observed that the pharmacological response presented by ayahuasca is linked to its anti-inflammatory action, attributed mainly to dimethyltryptamines (N, N-dimethyltryptamine and 5-methoxy-N, N-dimethyltryptamine), which act as endogenous systemic regulators of inflammation and immune homeostasis, also through sigma-1 receptors. Therefore, since neuroinflammation is among the main pathophysiological mechanisms related to the development of neurological and psychiatric diseases, we suggest, based on the available evidence, that ayahuasca is a promising and very safe therapeutic strategy since extremely high doses are required to reach toxicity. However, even so, additional studies are needed to confirm such evidence, as well as the complete elucidation of the mechanisms involved.

da Silva, M. G., Daros, G. C., & de Bitencourt, R. M. (2021). Anti-inflammatory activity of ayahuasca: therapeutical implications in neurological and psychiatric diseases. Behavioural brain research, 400, 113003. https://doi.org/10.1016/j.bbr.2020.113003

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