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Medicine

Exposure-Response Analysis to Assess the Concentration-QTc Relationship of Psilocybin/Psilocin

April 6, 2020 / Medicine, Mushrooms / Psilocybin, Other subjects, Papers, Psychotherapy, Publications, Safety, Toxicology / By / , ,

Abstract

Psilocybin is being developed for treating major depressive disorder. Psilocybin is readily dephosphorylated to psilocin upon absorption. The potential for psilocin proarrhythmic effect was assessed using a concentration-QTc interval (C-QTc) analysis from an open-label single ascending dose study of psilocybin. Psilocybin doses ranged from 0.3 to 0.6 mg/kg. This trial showed a significant but shallow C-QTc relationship. At the clinical dose of 25 mg, the mean psilocin maximum concentration is 18.7 ng/mL, and the associated mean (upper 90% confidence interval of mean) QTcF change is 2.1 (6.6) milliseconds. Given the short half-life of psilocin of about 4 hours, there would be no accumulation after monthly oral doses used in clinical trials. The upper limit of the 90% confidence interval of the model-predicted mean ΔQTcF crossed 10 milliseconds at a psilocin concentration of 31.1 ng/mL. At a supraclinical psilocin maximum concentration of about 60 ng/mL, ΔQTcF remains low, with a mean (upper limit of the 90% confidence interval) of 9.1 (17.9) milliseconds. This analysis enabled the characterization of the C-QTc relationship and prediction of QTc prolongation at the expected clinical and possible higher psilocybin doses.

Dahmane, E., Hutson, P. R., & Gobburu, J. V. (2020). Exposure‐Response Analysis to Assess the Concentration‐QTc Relationship of Psilocybin/Psilocin. Clinical Pharmacology in Drug Development.; 10.1002/cpdd.796

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Salvinorin A Does Not Affect Seizure Threshold in Mice

January 27, 2022 / Medicine, Papers, Salvia / Salvinorin A / Leave a Comment / By / , ,

Abstract

The κ-opioid receptor has recently gained attention as a new molecular target in the treatment of many psychiatric and neurological disorders including epilepsy. Salvinorin A is a potent plant-derived hallucinogen that acts as a highly selective κ-opioid receptor agonist. It has unique structure and pharmacological properties, but its influence on seizure susceptibility has not been studied so far. Therefore, the aim of the present study was to investigate the effect of salvinorin A on seizure thresholds in three acute seizure tests in mice. We also examined its effect on muscular strength and motor coordination. The obtained results showed that salvinorin A (0.1-10 mg/kg, i.p.) did not significantly affect the thresholds for the first myoclonic twitch, generalized clonic seizure, or forelimb tonus in the intravenous pentylenetetrazole seizure threshold test in mice. Likewise, it failed to affect the thresholds for tonic hindlimb extension and psychomotor seizures in the maximal electroshock- and 6 Hz-induced seizure threshold tests, respectively. Moreover, no changes in motor coordination (assessed in the chimney test) or muscular strength (assessed in the grip-strength test) were observed. This is a preliminary report only, and further studies are warranted to better characterize the effects of salvinorin A on seizure and epilepsy.

Socała, K., Doboszewska, U., & Wlaź, P. (2020). Salvinorin A Does Not Affect Seizure Threshold in Mice. Molecules (Basel, Switzerland), 25(5), 1204. https://doi.org/10.3390/molecules25051204

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N,N-dimethyltryptamine reduces infarct size and improves functional recovery following transient focal brain ischemia in rats

December 2, 2021 / DMT, Medicine, Neuroscience, Papers / Leave a Comment / By / , , , , , , , ,

Abstract

Background and purpose: N,N-dimethyltryptamine (DMT) is an endogenous ligand of the Sigma 1 receptor (Sig-1R) with documented in vitro cytoprotective properties against hypoxia. Our aim was to demonstrate the in vivo neuroprotective effect of DMT following ischemia-reperfusion injury in the rat brain.

Methods: Transient middle cerebral occlusion (MCAO) was induced for 60 min in male Wistar rats using the filament occlusion model under general anaesthesia. Before the removal of the filament the treatment group (n = 10) received an intra-peritoneal (IP) bolus of 1 mg/kg-body weight (bw) DMT dissolved in 1 ml 7% ethanol/saline vehicle, followed by a maintenance dose of 2 mg/Kg-bw/h delivered over 24 h via osmotic minipumps. Controls (n = 10) received a vehicle bolus only. A third group (n = 10) received a Sig-1R antagonist (BD1063, 1 mg/kg-bw bolus +2 mg/kg-bw/h maintenance) in parallel with the DMT. Lesion volume was measured by MRI 24 h following the MCAO. Shortly after imaging the animals were terminated, and the native brains and sera were removed. Four rats were perfusion fixed. Functional recovery was studied in two separate group of pre-trained animals (n = 8-8) using the staircase method for 30 days. The expression levels of proteins involved in apoptosis, neuroplasticity and inflammatory regulation were assessed by real-time qPCR and ELISA.

Results: DMT treated rats were characterized by lower ischemic lesion volume (p = .0373), and better functional recovery (p = .0084) compared to the controls. Sig-1R was expressed both in neurons and in microglia in the peri-infarct cortex, and the DMT induced change in the lesion volume was hindered by BD1063. Lower APAF1 expression (mRNA and protein) and higher BNDF levels were documented on DTM, while decreased TNF-α, IL1-β, IL-6 and increased IL-10 expressions indicated the compound’s anti-inflammatory potential.

Conclusion: Our results indicate a Sig-1R dependent reduction of the ischemic brain injury following exogenous DMT administration in rats, presumably through a combined anti-apoptotic, pro-neurotrophic and anti-inflammatory treatment effect.

Nardai, S., László, M., Szabó, A., Alpár, A., Hanics, J., Zahola, P., Merkely, B., Frecska, E., & Nagy, Z. (2020). N,N-dimethyltryptamine reduces infarct size and improves functional recovery following transient focal brain ischemia in rats. Experimental neurology, 327, 113245. https://doi.org/10.1016/j.expneurol.2020.113245

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Therapeutic mechanisms of psilocybin: Changes in amygdala and prefrontal functional connectivity during emotional processing after psilocybin for treatment-resistant depression

January 16, 2020 / Medicine, Mushrooms / Psilocybin, Neuroscience, Other subjects, Papers, Personal development, Personality, Psychiatry, Psychology, Psychopharmacology, Psychotherapy, Publications / By / , , , , ,

Abstract

BACKGROUND:

Psilocybin has shown promise as a treatment for depression but its therapeutic mechanisms are not properly understood. In contrast to the presumed actions of antidepressants, we recently found increased amygdala responsiveness to fearful faces one day after open-label treatment with psilocybin (25 mg) in 19 patients with treatment-resistant depression, which correlated with treatment efficacy.

AIMS:

Aiming to further unravel the therapeutic mechanisms of psilocybin, the present study extends this basic activation analysis. We hypothesised changed amygdala functional connectivity, more precisely decreased amygdala-ventromedial prefrontal cortex functional connectivity, during face processing after treatment with psilocybin.

METHODS:

Psychophysiological interaction analyses were conducted on functional magnetic resonance imaging data from a classic face/emotion perception task, with the bilateral amygdala and ventromedial prefrontal cortex time-series as physiological regressors. Average parameter estimates (beta weights) of significant clusters were correlated with clinical outcomes at one week.

RESULTS:

Results showed decreased ventromedial prefrontal cortex-right amygdala functional connectivity during face processing post- (versus pre-) treatment; this decrease was associated with levels of rumination at one week. This effect was driven by connectivity changes in response to fearful and neutral (but not happy) faces. Independent whole-brain analyses also revealed a post-treatment increase in functional connectivity between the amygdala and ventromedial prefrontal cortex to occipital-parietal cortices during face processing.

CONCLUSION:

These results are consistent with the idea that psilocybin therapy revives emotional responsiveness on a neural and psychological level, which may be a key treatment mechanism for psychedelic therapy. Future larger placebo-controlled studies are needed to examine the replicability of the current findings.

Mertens, L. J., Wall, M. B., Roseman, L., Demetriou, L., Nutt, D. J., & Carhart-Harris, R. L. (2020). Therapeutic mechanisms of psilocybin: Changes in amygdala and prefrontal functional connectivity during emotional processing after psilocybin for treatment-resistant depression. Journal of Psychopharmacology, 10.1177/0269881119895520
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Psilocybin Induces Time-Dependent Changes in Global Functional Connectivity

January 13, 2020 / Medicine, Mushrooms / Psilocybin, Neuroscience, Papers, Psychiatry, Psychology, Psychopharmacology, Psychotherapy, Publications / By / , , , , , ,

Abstract

Background

The use of psilocybin in scientific and experimental clinical contexts has triggered renewed interest in the mechanism of action of psychedelics. However, its time-dependent systems-level neurobiology remains sparsely investigated in humans.

Methods

We conducted a double-blind, randomized, counterbalanced, crossover study comprising 23 healthy human participants who received placebo and 0.2 mg/kg of psilocybin orally on 2 different test days. Participants underwent magnetic resonance imaging at 3 time points between administration and peak effects: 20 minutes, 40 minutes, and 70 minutes after administration. Resting-state functional connectivity was quantified via a data-driven global brain connectivity method and compared with cortical gene expression maps.

Results

Psilocybin reduced associative, but concurrently increased sensory, brain-wide connectivity. This pattern emerged over time from administration to peak effects. Furthermore, we showed that baseline connectivity is associated with the extent of psilocybin-induced changes in functional connectivity. Lastly, psilocybin-induced changes correlated in a time-dependent manner with spatial gene expression patterns of the 5-HT2A (5-hydroxytryptamine 2A) and 5-HT1A (5-hydroxytryptamine 1A) receptors.

Conclusions

These results suggest that the integration of functional connectivity in sensory regions and the disintegration in associative regions may underlie the psychedelic state and pinpoint the critical role of the serotonin 2A and 1A receptor systems. Furthermore, baseline connectivity may represent a predictive marker of the magnitude of changes induced by psilocybin and may therefore contribute to a personalized medicine approach within the potential framework of psychedelic treatment.

Preller, K. H., Duerler, P., Burt, J. B., Ji, J. L., Adkinson, B., Stämpfli, P., … & Anticevic, A. (2020). Psilocybin induces time-dependent changes in global functional connectivity: Psi-induced changes in brain connectivity. Biological Psychiatry., 10.1016/j.biopsych.2019.12.027
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In vivo effects of 3,4-methylenedioxymethamphetamine (MDMA) and its deuterated form in rodents: Drug discrimination and thermoregulation.

January 13, 2020 / Anxiety disorders / PTSD, Chemistry, MDMA, Medicine, New substances, Other substances, Papers, Psychopharmacology, Publications, Safety, Toxicology / By / , , ,

Abstract

BACKGROUND:

Recent clinical studies support the use of 3,4-methylenedioxymethamphetamine (MDMA) as an adjunct treatment for posttraumatic stress disorder (PTSD). Despite these promising findings, MDMA administration in controlled settings can increase blood pressure, heart rate, and body temperature. Previous studies indicate thatO-demethylated metabolites of MDMA contribute to its adverse effects. As such, limiting the conversion of MDMA to reactive metabolites may mitigate some of its adverse effects and potentially improve its safety profile for therapeutic use.

METHODS:

We compared the interoceptive and hyperthermic effects of a deuterium-substituted form of MDMA (d2-MDMA) to MDMA using rodent drug discrimination and biotelemetry procedures, respectively.

RESULTS:

Compared to MDMA, d2-MDMA produced full substitution for a 1.5 mg/kg MDMA training stimulus with equal potency and effectiveness in the drug discrimination experiment. In addition, d2-MDMA produced increases in body temperature that were shorter-lasting and of lower magnitude compared to equivalent doses of MDMA. Last, d2-MDMA and MDMA were equally effective in reversing the hypothermic effects of the selective 5-HT2A/2C antagonist ketanserin.

CONCLUSION:

These findings indicate that deuterium substitution of hydrogen at the methylenedioxy ring moiety does not impact MDMA’s interoceptive effects, and compared to MDMA, d2-MDMA has less potential for producing hyperthermic effects and likely has similar pharmacodynamic properties. Given that d2-MDMA produces less adverse effects than MDMA, but retains similar desirable effects that are thought to relate to the effective treatment of PTSD, additional investigations into its effects on cardiovascular functioning and pharmacokinetic properties are warranted.

Berquist, M. D., Leth-Petersen, S., Kristensen, J. L., & Fantegrossi, W. E. (2020). In vivo effects of 3, 4-methylenedioxymethamphetamine (MDMA) and its deuterated form in rodents: drug discrimination and thermoregulation. Drug and Alcohol Dependence, 107850., 10.1016/j.drugalcdep.2020.107850
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Antidepressant and neurocognitive effects of serial ketamine administration versus ECT in depressed patients

January 13, 2020 / Depression, Ketamine, Medicine, Neuroscience, Papers, Psychopharmacology, Psychotherapy, Publications / By / , , , , , ,

Abstract

BACKGROUND:

While electroconvulsive therapy (ECT) is considered the gold standard for acute treatment of patients with otherwise treatment-resistant depression, ketamine has recently emerged as a fast-acting treatment alternative for these patients. Efficacy and onset of action are currently among the main factors that influence clinical decision making, however, the effect of these treatments on cognitive functions should also be a crucial point, given that cognitive impairment in depression is strongly related to disease burden and functional recovery. ECT is known to induce transient cognitive impairment, while little is known about ketamine’s impact on cognition. This study therefore aims to compare ECT and serial ketamine administration not only with regard to their antidepressant efficacy but also to acute neurocognitive effects.

METHODS:

Fifty patients suffering from depression were treated with either serial ketamine infusions or ECT. Depression severity and cognitive functions were assessed before, during, and after treatment.

RESULTS:

ECT and ketamine administration were equally effective, however, the antidepressant effects of ketamine occurred faster. Ketamine improved neurocognitive functioning, especially attention and executive functions, whereas ECT was related to a small overall decrease in cognitive performance.

CONCLUSIONS:

Due to its pro-cognitive effects and faster antidepressant effect, serial ketamine administration might be a more favorable short-term treatment option than ECT.

LIMITATIONS:

As this research employed a naturalistic study design, patients were not systematically randomized, there was no control group and patients received concurrent and partially changing medications during treatment.

CLINICAL TRIALS REGISTRATION:

Functional and Metabolic Changes in the Course of Antidepressive Treatment, https://clinicaltrials.gov/ct2/show/NCT02099630, NCT02099630.

Basso, L., Bönke, L., Aust, S., Gärtner, M., Heuser-Collier, I., Otte, C., … & Grimm, S. (2020). Antidepressant and neurocognitive effects of serial ketamine administration versus ECT in depressed patients. Journal of Psychiatric Research.,  10.1016/j.jpsychires.2020.01.002

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4-MeO-PCP and 3-MeO-PCMo, new dissociative drugs, produce rewarding and reinforcing effects through activation of mesolimbic dopamine pathway and alteration of accumbal CREB, deltaFosB, and BDNF levels

December 11, 2019 / Addiction, Chemistry, Medicine, Neuroscience, Other substances, Papers, Psychopharmacology, Publications / By / , , , , , ,

Abstract

Rationale: A high number of synthetic dissociative drugs continue to be available through online stores, leading to their misuse. Recent inclusions in this category are 4-MeO-PCP and 3-MeO-PCMo, analogs of phencyclidine. Although the dissociative effects of these drugs and their recreational use have been reported, no studies have investigated their abuse potential.

Objectives: To examine their rewarding and reinforcing effects and explore the mechanistic correlations.

Methods: We used conditioned place preference (CPP), self-administration, and locomotor sensitization tests to assess the rewarding and reinforcing effects of the drugs. We explored their mechanism of action by pretreating dopamine receptor (DR) D1 antagonist SCH23390 and DRD2 antagonist haloperidol during CPP test and investigated the effects of 4-MeO-PCP and 3-MeO-PCMo on dopamine-related proteins in the ventral tegmental area and nucleus accumbens. We also measured the levels of dopamine, phosphorylated cyclic-AMP response element-binding (p-CREB) protein, deltaFosB, and brain-derived neurotrophic factor (BDNF) in the nucleus accumbens. Additionally, we examined the effects of both drugs on brain wave activity using electroencephalography.

Results: While both 4-MeO-PCP and 3-MeO-PCMo induced CPP and self-administration, only 4-MeO-PCP elicited locomotor sensitization. SCH23390 and haloperidol inhibited the acquisition of drug CPP. 4-MeO-PCP and 3-MeO-PCMo altered the levels of tyrosine hydroxylase, DRD1, DRD2, and dopamine, as well as that of p-CREB, deltaFosB, and BDNF. All drugs increased the delta and gamma wave activity, whereas pretreatment with SCH23390 and haloperidol inhibited it.

Conclusion: Our results indicate that 4-MeO-PCP and 3-MeO-PCMo induce rewarding and reinforcing effects that are probably mediated by the mesolimbic dopamine system, suggesting an abuse liability in humans.

Abiero, A., Botanas, C. J., Custodio, R. J., Sayson, L. V., Kim, M., Lee, H. J., … & Cheong, J. H. (2020). 4-MeO-PCP and 3-MeO-PCMo, new dissociative drugs, produce rewarding and reinforcing effects through activation of mesolimbic dopamine pathway and alteration of accumbal CREB, deltaFosB, and BDNF levels. Psychopharmacology, 237(3), 757-772; 10.1007/s00213-019-05412-y

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Prospective examination of synthetic 5-methoxy-N,N-dimethyltryptamine inhalation: effects on salivary IL-6, cortisol levels, affect, and non-judgment

December 10, 2019 / Chemistry, DMT, Medicine, Neuroscience, Other substances, Papers, Psychopharmacology, Psychotherapy, Publications / By / , , , , ,

Abstract

Rationale

5-methoxy-N,N-dimethyltryptamine is a psychotropic substance found in various plant and animal species and is synthetically produced. 5-methoxy-N,N-dimethyltryptamine is used in naturalistic settings for spiritual exploration, recreation, or to address negative affect and mood problems. However, scientific knowledge on the effects of 5-methoxy-N,N-dimethyltryptamine in humans is scarce.

Objectives

The first objective was to assess the effects of inhalation of vaporized synthetic 5-methoxy-N,N-dimethyltryptamine on neuroendocrine markers. The second objective was to assess effects of the substance on affect and mindfulness. In addition, we assessed whether ratings of subjective measures were associated with changes in stress biomarkers (i.e., cortisol) and immune response (i.e., IL-6, CRP, IL-1β), as well as the acute psychedelic experience.

Methods

Assessments (baseline, immediately post-session, and 7-day follow-up) were made in 11 participants. Salivary samples were collected at baseline and post-session and analyzed by high-sensitivity enzyme-linked immunosorbent assay (ELISA).

Results

5-methoxy-N,N-dimethyltryptamine significantly increased cortisol levels and decreased IL-6 concentrations in saliva immediately post-session. These changes were not correlated to ratings of mental health or the psychedelic experience. Relative to baseline, ratings of non-judgment significantly increased, and ratings of depression decreased immediately post-session and at follow-up. Ratings of anxiety and stress decreased from baseline to 7-day follow-up. Participant ratings of the psychedelic experience correlated negatively with ratings of affect and positively with ratings of non-judgment.

Conclusion

Inhalation of vaporized synthetic 5-methoxy-N,N-dimethyltryptamine produced significant changes in inflammatory markers, improved affect, and non-judgment in volunteers. Future research should examine the effect of 5-methoxy-N,N-dimethyltryptamineamine with healthy volunteers in a controlled laboratory setting.

Uthaug, M. V., Lancelotta, R., Szabo, A., Davis, A. K., Riba, J., & Ramaekers, J. G. (2019). Prospective examination of synthetic 5-methoxy-N, N-dimethyltryptamine inhalation: effects on salivary IL-6, cortisol levels, affect, and non-judgment. Psychopharmacology, 1-13., 10.1007/s00213-019-05414-w
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7 May - Psychedelics, Nature & Mental Health with Sam Gandy

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