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The serotonin hallucinogen 5-MeO-DMT alters cortico-thalamic activity in freely moving mice: Regionally-selective involvement of 5-HT1A and 5-HT2A receptors

December 6, 2017 / Depression, Neuroscience, Other substances, Papers, Psychology, Psychopharmacology, Publications / By / , , ,

Abstract

5-MeO-DMT is a natural hallucinogen acting as serotonin 5-HT1A/5-HT2A receptor agonist. Its ability to evoke hallucinations could be used to study the neurobiology of psychotic symptoms and to identify new treatment targets. Moreover, recent studies revealed the therapeutic potential of serotonin hallucinogens in treating mood and anxiety disorders. Our previous results in anesthetized animals show that 5-MeO-DMT alters cortical activity via 5-HT1A and 5-HT2A receptors. Here, we examined 5-MeO-DMT effects on oscillatory activity in prefrontal (PFC) and visual (V1) cortices, and in mediodorsal thalamus (MD) of freely-moving wild-type (WT) and 5-HT2A-R knockout (KO2A) mice. We performed local field potential multi-recordings evaluating the power at different frequency bands and coherence between areas. We also examined the prevention of 5-MeO-DMT effects by the 5-HT1A-R antagonist WAY-100635. 5-MeO-DMT affected oscillatory activity more in cortical than in thalamic areas. More marked effects were observed in delta power in V1 of KO2A mice. 5-MeO-DMT increased beta band coherence between all examined areas. In KO2A mice, WAY100635 prevented most of 5-MeO-DMT effects on oscillatory activity. The present results indicate that hallucinatory activity of 5-MeO-DMT is likely mediated by simultaneous alteration of prefrontal and visual activities. The prevention of these effects by WAY-100635 in KO2A mice supports the potential usefulness of 5-HT1A receptor antagonists to treat visual hallucinations. 5-MeO-DMT effects on PFC theta activity and cortico-thalamic coherence may be related to its antidepressant activity.
Riga, M. S., Lladó-Pelfort, L., Artigas, F., & Celada, P. (2017). The serotonin hallucinogen 5-MeO-DMT alters cortico-thalamic activity in freely moving mice: Regionally-selective involvement of 5-HT 1A and 5-HT 2A receptors. Neuropharmacology. 10.1016/j.neuropharm.2017.11.049

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Acute effects of methylphenidate, modafinil and MDMA on negative emotion processing

December 1, 2017 / MDMA, Other subjects, Papers, Psychology, Publications / By / , , , , ,

Abstract

BACKGROUND:
Stimulants such as methylphenidate (MPH) and modafinil are frequently used as cognitive enhancers in healthy people, whereas 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) is proposed to enhance mood and empathy in healthy subjects. However, comparative data on the effects of MPH and modafinil on negative emotions in healthy subjects have been widely missing. The aim of this study was to compare the acute effects of MPH and modafinil on the neural correlates of fearful face processing using MDMA as a positive control.
METHODS:
Using a double-blind within-subject placebo-controlled cross-over design, 60 mg MPH, 600 mg modafinil, and 125 mg MDMA were administrated to 22 healthy subjects, while performing an event-related fMRI task to assess brain activation in response to fearful faces. Negative mood states were assessed with the State-Trait Anxiety Inventory and subjective ratings.
RESULTS:
Relative to placebo, modafinil, but not MPH or MDMA, increased brain activation within a limbic-cortical-striatal-pallidal-thalamic circuit during fearful face processing. Modafinil but not MPH also increased amydgala responses to fearful faces compared with MDMA. Furthermore, activation in the middle and inferior frontal gyrus in response to fearful faces correlated positively with subjective feelings of fearfulness and depressiveness after modafinil administration.
CONCLUSIONS:
In spite of the cognitive enhancement effects of 600 mg modafinil in healthy people, potential adverse effects on emotion processing should be considered.
Schmidt, A., Müller, F., Dolder, P. C., Schmid, Y., Zanchi, D., Egloff, L., … & Borgwardt, S. (2017). Acute effects of methylphenidate, modafinil and MDMA on negative emotion processing. International Journal of Neuropsychopharmacology, pyx112. 10.1093/ijnp/pyx112
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Ketamine and pharmacological imaging: use of functional magnetic resonance imaging to evaluate mechanisms of action

November 30, 2017 / Depression, Ketamine, Neuroscience, Other subjects, Papers, Psychiatry, Psychology, Psychopharmacology, Psychosis, Publications / By / , ,

Abstract

Ketamine has been used as a pharmacological model for schizophrenia as subanesthetic infusions have been shown to produce temporary schizophrenia-like symptoms in healthy humans. More recently, ketamine has emerged as a potential treatment for multiple psychiatric disorders, including treatment-resistant depression and suicidal ideation. However, the mechanisms underlying both the psychotomimetic and the therapeutic effects of ketamine remain poorly understood. This review provides an overview of what is known of the neural mechanisms underlying the effects of ketamine and details what functional MRI studies have yielded at a systems level focused on brain circuitry. Multiple analytic approaches show that ketamine exerts robust and consistent effects at the whole-brain level. These effects are highly conserved across human and nonhuman primates, validating the use of nonhuman primate models for further investigations with ketamine. Regional analysis of brain functional connectivity suggests that the therapeutic potential of ketamine may be derived from a strengthening of executive control circuitry, making it an intriguing candidate for the treatment of drug abuse. There are still important questions about the mechanism of action and the therapeutic potential of ketamine that can be addressed using appropriate functional neuroimaging techniques.
Maltbie, E. A., Kaundinya, G. S., & Howell, L. L. (2017). Ketamine and pharmacological imaging: use of functional magnetic resonance imaging to evaluate mechanisms of action. Behavioural Pharmacology, 28(8), 610-622. 10.1097/FBP.0000000000000354
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Effects of harmaline on cell growth of human liver cancer through the p53/p21 and Fas/FasL signaling pathways

November 28, 2017 / Ayahuasca, Medicine, Other subjects, Papers, Publications / By / , , , , , ,

Abstract

The effects of harmaline on the viability and apoptosis of human liver carcinoma were investigated in vitro. HepG2 cells were treated with harmaline (0‑10 µM), and the proliferation and apoptosis of HepG2 cells were investigated using an MTT assay and flow cytometry, respectively. The protein expression of cellular tumor antigen p53 (p53), cyclin‑dependent kinase inhibitor 1 (p21), tumor necrosis factor receptor superfamily member 6 (Fas), Fas ligand (FasL) and caspase‑8 was subsequently measured using western blotting. In addition, an ELISA was used to analyze caspase‑8/3 activity. Harmaline significantly increased p53, p21, Fas and FasL protein expression in HepG2 cells. Additionally, treatment with harmaline significantly increased the expression of caspase‑8 and caspase‑8/3 activity. The results from the present study suggest that harmaline suppresses the viability, but induces the apoptosis, of human liver carcinoma cells through upregulation of the p53/p21 and Fas/FasL signaling pathways.
Xu, B., Li, M., Yu, Y., He, J., Hu, S., Pan, M., … & Zhu, J. (2018). Effects of harmaline on cell growth of human liver cancer through the p53/p21 and Fas/FasL signaling pathways. Oncology Letters, 15(2), 1931-1936. 10.3892/ol.2017.7495
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Psychedelics and reconsolidation of traumatic and appetitive maladaptive memories: focus on cannabinoids and ketamine

November 25, 2017 / Depression, Ketamine, MDMA, Papers, Psychiatry, Psychology, Publications, Substance Use Disorder / By / , , , ,

Abstract

Rationale

Clinical data with 3,4-methylenedioxymethamphetamine (MDMA) in post-traumatic stress disorder (PTSD) patients recently stimulated interest on the potential therapeutic use of psychedelics in disorders characterized by maladaptive memories, including substance use disorders (SUD). The rationale for the use of MDMA in PTSD and SUD is being extended to a broader beneficial “psychedelic effect,” which is supporting further clinical investigations, in spite of the lack of mechanistic hypothesis. Considering that the retrieval of emotional memories reactivates specific brain mechanisms vulnerable to inhibition, interference, or strengthening (i.e., the reconsolidation process), it was proposed that the ability to retrieve and change these maladaptive memories might be a novel intervention for PTSD and SUD. The mechanisms underlying MDMA effects indicate memory reconsolidation modulation as a hypothetical process underlying its efficacy.

Objective

Mechanistic and clinical studies with other two classes of psychedelic substances, namely cannabinoids and ketamine, are providing data in support of a potential use in PTSD and SUD based on the modulation of traumatic and appetitive memory reconsolidation, respectively. Here, we review preclinical and clinical data on cannabinoids and ketamine effects on biobehavioral processes related to the reconsolidation of maladaptive memories.

Results

We report the findings supporting (or not) the working hypothesis linking the potential therapeutic effect of these substances to the underlying reconsolidation process. We also proposed possible approaches for testing the use of these two classes of drugs within the current paradigm of reconsolidation memory inhibition.

Conclusions

Metaplasticity may be the process in common between cannabinoids and ketamine/ketamine-like substance effects on the mediation and potential manipulation of maladaptive memories.

Fattore, L., Piva, A., Zanda, M. T., Fumagalli, G., & Chiamulera, C. (2017). Psychedelics and reconsolidation of traumatic and appetitive maladaptive memories: focus on cannabinoids and ketamine. Psychopharmacology, 1-13. 10.1007/s00213-017-4793-4
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A regulatory perspective on the evaluation of hallucinogen drugs for human use

November 24, 2017 / Other disciplines, Other subjects, Other substances, Papers, Publications, Safety / By / , ,

Abstract

In recent years, there is renewed interest in the study of various hallucinogens for their potential therapeutic effects. In the United States of America (USA), the abuse potential assessment of a drug is carried out as part of the general safety and efficacy evaluation of a drug. Additionally, the abuse potential assessment is taken under consideration in determining if a drug needs to be subject to controls to minimize the abuse of the drug once on the market. This assessment is conducted for all new drugs with central nervous system (CNS) activity, that are chemically or pharmacologically similar to other drugs with known abuse potential, or drugs that produce psychoactive effects predictive of abuse, such as euphoria and hallucinations. This paper describes the regulatory framework for evaluating the abuse potential of new drugs, with emphasis on hallucinogens. The paper discusses the role of the United States Food and Drug Administration (FDA) in the evaluation of the abuse potential of drugs and its role in drug control, and provides an overview of the controlled status of hallucinogens and the requirements to conduct research with Schedule I substances in the USA.

Calderon, S. N., Hunt, J., & Klein, M. (2017). A regulatory perspective on the evaluation of hallucinogen drugs for human use. Neuropharmacology. 10.1016/j.neuropharm.2017.11.028
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TrkB dependent adult hippocampal progenitor differentiation mediates sustained ketamine antidepressant response

November 21, 2017 / Depression, Ketamine, Neuroscience, Papers, Psychopharmacology, Publications / By / , , , , , ,

Abstract

Adult neurogenesis persists in the rodent dentate gyrus and is stimulated by chronic treatment with conventional antidepressants through BDNF/TrkB signaling. Ketamine in low doses produces both rapid and sustained antidepressant effects in patients. Previous studies have shed light on post-transcriptional synaptic NMDAR mediated mechanisms underlying the acute effect, but how ketamine acts at the cellular level to sustain this anti-depressive function for prolonged periods remains unclear. Here we report that ketamine accelerates differentiation of doublecortin-positive adult hippocampal neural progenitors into functionally mature neurons. This process requires TrkB-dependent ERK pathway activation. Genetic ablation of TrkB in neural stem/progenitor cells, or pharmacologic disruption of ERK signaling, or inhibition of adult neurogenesis, each blocks the ketamine-induced behavioral responses. Conversely, enhanced ERK activity via Nf1 gene deletion extends the response and rescues both neurogenic and behavioral deficits in mice lacking TrkB. Thus, TrkB-dependent neuronal differentiation is involved in the sustained antidepressant effects of ketamine.
Ma, Z., Zang, T., Birnbaum, S. G., Wang, Z., Johnson, J. E., Zhang, C. L., & Parada, L. F. (2017). TrkB dependent adult hippocampal progenitor differentiation mediates sustained ketamine antidepressant response. Nature communications, 8(1), 1668. 10.1038/s41467-017-01709-8
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Progress and promise for the MDMA drug development program

November 20, 2017 / Anxiety disorders / PTSD, MDMA, Papers, Psychiatry, Psychology, Psychotherapy, Publications / By / , ,

Abstract

Pharmacotherapy is often used to target symptoms of posttraumatic stress disorder (PTSD), but does not provide definitive treatment, and side effects of daily medication are often problematic. Trauma-focused psychotherapies are more likely than drug treatment to achieve PTSD remission, but have high dropout rates and ineffective for a large percentage of patients. Therefore, research into drugs that might increase the effectiveness of psychotherapy is a logical avenue of investigation. The most promising drug studied as a catalyst to psychotherapy for PTSD thus far is 3,4-methylenedioxymethamphetamine (MDMA), commonly known as the recreational drug “Ecstasy.” MDMA stimulates the release of hormones and neurochemicals that affect key brain areas for emotion and memory processing. A series of recently completed phase 2 clinical trials of MDMA-assisted psychotherapy for treatment of PTSD show favorable safety outcomes and large effect sizes that warrant expansion into multi-site phase 3 trials, set to commence in 2018. The nonprofit sponsor of the MDMA drug development program, the Multidisciplinary Association for Psychedelic Studies (MAPS), is supporting these trials to explore whether MDMA, administered on only a few occasions, can increase the effectiveness of psychotherapy. Brain imaging techniques and animal models of fear extinction are elucidating neural mechanisms underlying the robust effects of MDMA on psychological processing; however, much remains to be learned about the complexities of MDMA effects as well as the complexities of PTSD itself.
Feduccia, A. A., Holland, J., & Mithoefer, M. C. (2017). Progress and promise for the MDMA drug development program. Psychopharmacology, 1-11. 10.1007/s00213-017-4779-2
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The ‘Endless Trip’: Psychopathology and Psychopharmacology in the Hallucinogen Persisting Perception Disorder/HPPD and the NPS. A systematic review

November 20, 2017 / New substances, Other substances, Papers, Psychology, Publications / By / , , , , ,

Abstract

Hallucinogen-persisting perception disorder (HPPD) is a syndrome characterized by prolonged or reoccurring perceptual symptoms, reminiscent of acute hallucinogen effects. HPPD was associated with a broader range of LSD (lysergic acid diethylamide)-like substances, cannabis, methylenedioxymethamphetamine (MDMA), psilocybin, mescaline, and psychostimulants. The recent emergence of novel psychoactive substances (NPS) posed a critical concern regarding the new onset of psychiatric symptoms/syndromes, including cases of HPPD. Symptomatology mainly comprises visual disorders (i.e., geometric pseudo-hallucinations, haloes, flashes of colors/lights, motion-perception deficits, afterimages, micropsia, more acute awareness of floaters, etc.), even though depressive symptoms and thought disorders may be comorbidly present. Although HPPD was first described in 1954, it was just established as a fully syndrome in 2000, with the revised fourth version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR). HPPD neural substrates, risk factors, and aetiopathogenesys still largely remain unknown and under investigation, and many questions about its pharmacological targets remain unanswered too. A critical mini review on psychopathological bases, etiological hypothesis, and psychopharmacological approaches toward HPPD, including the association with some novel substances, are provided here, by means of a literature search on PubMed/Medline, Google Scholar, and Scopus databases without time restrictions, by using a specific set of keywords. Pharmacological and clinical issues are considered, and practical psychopharmacological recommendations and clinical guidelines are suggested.
Orsolini, L., Papanti, G. D., De Berardis, D., Guirguis, A., Corkery, J. M., & Schifano, F. (2017). The ‘Endless Trip’: Psychopathology and Psychopharmacology in the Hallucinogen Persisting Perception Disorder/HPPD and the NPS. A systematic review. Frontiers in Psychiatry, 8, 240. 10.3389/fpsyt.2017.00240
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Studies with psychedelic drugs in human volunteers

November 18, 2017 / DMT, Ketamine, MDMA, Papers, Psychiatry, Psychology, Psychopharmacology, Psychotherapy, Publications / By / , ,

Abstract

Scientific curiosity and fascination have played a key role in human research with psychedelics along with the hope that perceptual alterations and heightened insight could benefit well-being and play a role in the treatment of various neuropsychiatric disorders. These motivations need to be tempered by a realistic assessment of the hurdles to be cleared for therapeutic use. Development of a psychedelic drug for treatment of a serious psychiatric disorder presents substantial although not insurmountable challenges. While the varied psychedelic agents described in this chapter share some properties, they have a range of pharmacologic effects that are reflected in the gradation in intensity of hallucinogenic effects from the classical agents to DMT, MDMA, ketamine, dextromethorphan and new drugs with activity in the serotonergic system. The common link seems to be serotonergic effects modulated by NMDA and other neurotransmitter effects. The range of hallucinogens suggest that they are distinct pharmacologic agents and will not be equally safe or effective in therapeutic targets. Newly synthesized specific and selective agents modeled on the legacy agents may be worth considering. Defining therapeutic targets that represent unmet medical need, addressing market and commercial issues, and finding treatment settings to safely test and use such drugs make the human testing of psychedelics not only interesting but also very challenging.
Sellers, E. M., Romach, M. K., & Leiderman, D. B. (2017). Studies with psychedelic drugs in human volunteers. Neuropharmacology. 10.1016/j.neuropharm.2017.11.029
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