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Pharmacokinetics and Pharmacodynamics of Lysergic Acid Diethylamide in Healthy Subjects

Abstract

Background and Objective: Lysergic acid diethylamide (LSD) is used recreationally and in clinical research. The aim of the present study was to characterize the pharmacokinetics and exposure–response relationship of oral LSD.

Methods: We analyzed pharmacokinetic data from two published placebo-controlled, double-blind, cross-over studies using oral administration of LSD 100 and 200 µg in 24 and 16 subjects, respectively. The pharmacokinetics of the 100-µg dose is shown for the first time and data for the 200-µg dose were reanalyzed and included. Plasma concentrations of LSD, subjective effects, and vital signs were repeatedly assessed. Pharmacokinetic parameters were determined using compartmental modeling. Concentration-effect relationships were described using pharmacokinetic-pharmacodynamic modeling.

Results: Geometric mean (95% confidence interval) maximum plasma concentration values of 1.3 (1.2–1.9) and 3.1 (2.6–4.0) ng/mL were reached 1.4 and 1.5 h after administration of 100 and 200 µg LSD, respectively. The plasma half-life was 2.6 h (2.2–3.4 h). The subjective effects lasted (mean ± standard deviation) 8.2 ± 2.1 and 11.6 ± 1.7 h for the 100- and 200-µg LSD doses, respectively. Subjective peak effects were reached 2.8 and 2.5 h after administration of LSD 100 and 200 µg, respectively. A close relationship was observed between the LSD concentration and subjective response within subjects, with moderate counterclockwise hysteresis. Half-maximal effective concentration values were in the range of 1 ng/mL. No correlations were found between plasma LSD concentrations and the effects of LSD across subjects at or near maximum plasma concentration and within dose groups.

Conclusions: The present pharmacokinetic data are important for the evaluation of clinical study findings (e.g., functional magnetic resonance imaging studies) and the interpretation of LSD intoxication. Oral LSD presented dose-proportional pharmacokinetics and first-order elimination up to 12 h. The effects of LSD were related to changes in plasma concentrations over time, with no evidence of acute tolerance.

Dolder, P. C., Schmid, Y., Steuer, A. E., Kraemer, T., Rentsch, K. M., Hammann, F., & Liechti, M. E. (2017). Pharmacokinetics and Pharmacodynamics of Lysergic Acid Diethylamide in Healthy Subjects. Clinical Pharmacokinetics, 1-12. 10.1007/s40262-017-0513-9

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The association of psychedelic use and opioid use disorders among illicit users in the United States

Short term changes in the proteome of human cerebral organoids induced by 5-methoxy-N,N-dimethyltryptamine

Abstract

Dimethyltryptamines are hallucinogenic serotonin-like molecules present in traditional Amerindian medicine (e.g. Ayahuasca, Virola) recently associated with cognitive gains, antidepressant effects and changes in brain areas related to attention, self-referential thought, and internal mentation. Historical and technical restrictions impaired understanding how such substances impact human brain metabolism. Here we used shotgun mass spectrometry to explore proteomic differences induced by dimethyltryptamine (5-methoxy-N,N-dimethyltryptamine, 5-MeO-DMT) on human cerebral organoids. Out of the 6,728 identified proteins, 934 were found differentially expressed in 5-MeO-DMT-treated cerebral organoids. In silico systems biology analyses support 5-MeO-DMT’s anti-inflammatory effects and reveal a modulation of proteins associated with the formation of dendritic spines, including proteins involved in cellular protrusion formation, microtubule dynamics and cytoskeletal reorganization. Proteins involved in long-term potentiation were modulated in a complex manner, with significant increases in the levels of NMDAR, CaMKII and CREB, but a reduction of PKA and PKC levels. These results offer possible mechanistic insights into the neuropsychological changes caused by the ingestion of substances rich in dimethyltryptamines.

Dakic, V., Nascimento, J. M., Sartore, R. C., de Moraes Maciel, R., de Araujo, D. B., Ribeiro, S., … & Rehen, S. K. (2017). Short term changes in the proteome of human cerebral organoids induced by 5-methoxy-N, N-dimethyltryptamine. bioRxiv, 108159.
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Science, spirituality, and ayahuasca: The problem of consciousness and spiritual ontologies in the academy

Abstract

Ayahuasca is a psychoactive brew from Amazonas, popularized in the last decades in part through transnational religious networks, but also due to interest in exploring spirituality through altered states of consciousness among academic schools and scientific researchers. In this article, the author analyzes the relation between science and religion proposing that the “demarcation problem” between the two arises from the relations among consciousness, intentionality, and spirituality. The analysis starts at the beginning of modern science, continues through the nineteenth century, and then examines the appearance of new schools in psychology and anthropology in the countercultural milieu of the 1960s. The author analyzes the case of ayahuasca against this historical background, first, in the general context of ayahuasca studies in the academic field. Second, he briefly describes three cases from Spain. Finally, he discusses the permeability of science to “spiritual ontologies” from an interdisciplinary perspective, using insights from social and cognitive sciences.

Apud, I. (2017). Science, spirituality, and ayahuasca: The problem of consciousness and spiritual ontologies in the academy. Zygon®, 52(1), 100-123. 10.1111/zygo.12315
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A unique natural selective kappa-opioid receptor agonist, salvinorin A, and its roles in human therapeutics

Abstract

Until the mid-60s, only the Mazatecs, an indigenous group from Oaxaca, Mexico, used Salvia Divinorum (S. divinorum) due to its hallucinogen properties.

Later it was found that the hallucinogen effects of this plant were caused by the presence of a neoclerodane diterpene Salvinorin A (salvinorin A), which is a highly selective agonist of kappa-opioid receptor (KOR) that cause more intense hallucinations than the common hallucinogens as lysergic acid, mushrooms, ecstasy and others. In fact, smoking of only 200–500 μg of S. divinorum leaves is enough to produce these effects thus making it the most potent natural occurring hallucinogen known.

Due to its legal status in various countries, this compound has gained a worldwide popularity as a drug of abuse with an easy access through smartshops and internet.

Furthermore, salvinorin A gathered an increased interest in the scientific community thanks to its unique structure and properties, and various studies demonstrated that salvinorin A has antinociceptive, antidepressant, in some circumstances pro-depressant and anti-addictive effects that have yielded potential new avenues for research underlying salvinorin A and its semi-synthetic analogs as therapeutic agents.

Cruz, A., Domingos, S., Gallardo, E., & Martinho, A. (2017). A unique natural selective kappa-opioid receptor agonist, salvinorin A, and its roles in human therapeutics. Phytochemistry. 10.1016/j.phytochem.2017.02.001
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Toxicokinetics of ibogaine and noribogaine in a patient with prolonged multiple cardiac arrhythmias after ingestion of internet purchased ibogaine

Abstract

BACKGROUND:
Ibogaine is an agent that has been evaluated as an unapproved anti-addictive agent for the management of drug dependence. Sudden cardiac death has been described to occur secondary to its use. We describe the clinical effects and toxicokinetics of ibogaine and noribogaine in a single patient. For this purpose, we developed a LC-MS/MS-method to measure ibogaine and noribogaine plasma-concentrations. We used two compartments with first order absorption.
CASE DETAILS:
The maximum concentration of ibogaine was 1.45 mg/L. Our patient developed markedly prolonged QTc interval of 647ms maximum, several multiple cardiac arrhythmias (i.e., atrial tachycardia and ventricular tachycardia and Torsades des Pointes). QTc-prolongation remained present until 12 days after ingestion, several days after ibogaine plasma-levels were low, implicating clinically relevant noribogaine concentrations long after ibogaine had been cleared from the plasma. The ratio k12/k21 for noribogaine was 21.5 and 4.28 for ibogaine, implicating a lower distribution of noribogaine from the peripheral compartment into the central compartment compared to ibogaine.
CONCLUSIONS:
We demonstrated a linear relationship between the concentration of the metabolite and long duration of action, rather than with parent ibogaine. Therefore, after (prolonged) ibogaine ingestion, clinicians should beware of long-term effects due to its metabolite.
Henstra, M., Wong, L., Chahbouni, A., Swart, N., Allaart, C., & Sombogaard, F. (2017). Toxicokinetics of ibogaine and noribogaine in a patient with prolonged multiple cardiac arrhythmias after ingestion of internet purchased ibogaine. Clinical Toxicology55(6), 600-602. 10.1080/15563650.2017.1287372
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Potential Antitumor Effect of Harmine in the Treatment of Thyroid Cancer

Abstract

Thyroid cancer is one of the most common types of cancer in endocrine system. In latest studies, harmine has been proved to inhibit the growth of several cancers in vitro and in vivo. In the current study, we evaluated the in vitro and in vivo anticancer efficiency of harmine against thyroid cancer cell line TPC-1. The in vitro cytotoxicity of harmine evaluated by XTT assay indicated that harmine suppressed the proliferation of TPC-1 cells in a dose- and time-dependent manner. Moreover, harmine dose-dependently induced apoptosis of TPC-1 cells through regulating the ratio of Bcl-2/Bax. The colony forming ability of TPC-1 cells was also time-dependently inhibited by harmine. The inhibitory effects of harmine on migration and invasion of TPC-1 cells were studied by wound scratching and Transwell assays. In vivo evaluation showed that harmine effectively inhibited the growth of thyroid cancer in a dose-dependent manner in nude mice. Therefore, harmine might be a promising herbal medicine in the therapy of thyroid cancer and further efforts are needed to explore this therapeutic strategy.

Ruan, S., Jia, F., & Li, J. (2017). Potential Antitumor Effect of Harmine in the Treatment of Thyroid Cancer. Evidence-Based Complementary and Alternative Medicine, 2017. 10.1155/2017/9402615
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Rapid antidepressant effect of ketamine correlates with astroglial plasticity in the hippocampus

Abstract

BACKGROUND AND PURPOSE: Astroglia contribute to the pathophysiology of major depression and antidepressant drugs act by modulating synaptic plasticity; therefore, the present study investigated whether the fast antidepressant action of ketamine is reflected in a rapid alteration of the astrocytes’ morphology in a genetic animal model of depression.

EXPERIMENTAL APPROACH: S-Ketamine (15 mg·kg-1 ) or saline was administered as a single injection to Flinders Line (FSL/ FRL) rats. Twenty-four hours after the treatment, perfusion fixation was carried out and the morphology of glial fibrillary acid protein (GFAP)-positive astrocytes in the CA1 stratum radiatum (CA1.SR) and the molecular layer of the dentate gyrus (GCL) of the hippocampus was investigated by applying stereological techniques and analysis with Imaris software. The depressive-like behaviour of animals was also evaluated using forced swim test.

KEY RESULTS: FSL rats treated with ketamine exhibited a significant reduction in immobility time in comparison with the FSL-vehicle group. The volumes of the hippocampal CA1.SR and GCL regions were significantly increased 1 day after ketamine treatment in the FSL rats. The size of astrocytes in the ketamine-treated FSL rats was larger than those in the FSL-vehicle group. Additionally, the number and length of the astrocytic processes in the CA1.SR region were significantly increased 1 day following ketamine treatment.

CONCLUSIONS AND IMPLICATIONS: Our results support the hypothesis that astroglial atrophy contributes to the pathophysiology of depression and a morphological modification of astrocytes could be one mechanism by which ketamine rapidly improves depressive behaviour.

Ardalan, M., Rafati, A. H., Nyengaard, J. R., & Wegener, G. (2017). Rapid antidepressant effect of ketamine correlates with astroglial plasticity in the hippocampus. British Journal of Pharmacology, 174(6), 483-492. 10.1111/bph.13714
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Sub-anesthetic doses of ketamine exert antidepressant-like effects and upregulate the expression of glutamate transporters in the hippocampus of rats

Abstract

Clinical studies on the role of the glutamatergic system in the pathogenesis of depression found that ketamine induces an antidepressant response, but the molecular mechanisms remain unclear. The present study investigated the effects of sub-anesthetic doses of ketamine on the glutamate reuptake function in the rat hippocampus. Chronic unpredictable mild stress (CUMS) was applied to construct animal models of depression. Sixty adult male Sprague-Dawley rats were randomly assigned to 5 groups and received a different regimen of CUMS and ketamine (10, 25, and 50 mg/kg) treatment. The sucrose preference test and open-field test were used to assess behavioral changes. The expression levels of excitatory amino acid transporters (EAATs) were measured by western blot. Microdialysis and high-performance liquid chromatography (HPLC) were used to detect hippocampal glutamate concentrations. We found that the expression of EAAT2 and EAAT3 were obviously downregulated, and extracellular concentrations of glutamate were significantly increased in the hippocampi of depressive-like rats. Ketamine (10, 25, and 50 mg/kg) upregulated the expression of EAAT2 and EAAT3, decreased the hippocampal concentration of extracellular glutamate, and alleviated the rats’ depressive-like behavior. The antidepressant effect of ketamine may be linked to the regulation of EAAT expression and the enhancement of glutamate uptake in the hippocampus of depressive-like rats.

Zhu, X., Ye, G., Wang, Z., Luo, J., & Hao, X. (2017). Sub-anesthetic doses of ketamine exert antidepressant-like effects and upregulate the expression of glutamate transporters in the hippocampus of rats. Neuroscience Letters, 639, 132-137. 10.1016/j.neulet.2016.12.070
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Disrupted integration of sensory stimuli with information about the movement of the body as a mechanism explaining LSD-induced experience

Abstract

LSD (lysergic acid diethylamide) is a model psychedelic drug used to study mechanism underlying the effects induced by hallucinogens. However, despite advanced knowledge about molecular mechanism responsible for the effects induced by LSD and other related substances acting at serotonergic 5-HT2a receptors, we still do not understand how these drugs trigger specific sensory experiences. LSD-induced experience is characterised by perception of movement in the environment and by presence of various bodily sensations such as floating in space, merging into surroundings and movement out of the physical body (the out-of-body experience). It means that a large part of the experience induced by the LSD can be simplified to the illusory movement that can be attributed to the self or to external objects. The phenomenology of the LSD-induced experience has been combined with the fact that serotonergic neurons provide all major parts of the brain with information about the level of tonic motor activity, occurrence of external stimuli and the execution of orienting responses. Therefore, it has been proposed that LSD-induced stimulation of 5-HT2a receptors disrupts the integration of the sensory stimuli with information about the movement of the body leading to perception of illusory movement.

Juszczak, G. R. (2017). Disrupted integration of sensory stimuli with information about the movement of the body as a mechanism explaining LSD-induced experience. Medical Hypotheses, 100, 94-97. 10.1016/j.mehy.2017.01.022
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