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Neuroscience

Is Ayahuasca a Potential Ethnic Plant for the Treatment of Parkinson’s Disease?

Abstract

Objective: Investigate the MAO inhibitory properties, toxicity, behavioral and neuroprotective properties of ayahuasca in mice and dopamine rich neuroblastoma cells in order to assess its potential effects on PD. 

Methods: This study examined the effects of the soluble extract of Banisteriopsis caapi on the activity MAO in mouse brain, the MAO inhibitory activity using HPLC with electrochemical detection and the animal´s behavior in an open field and marble burying test. In vitro cell-based assays in neuroblastoma NB69 cells were employed for evaluation of the antioxidant property of ayahuasca by measuring the auto-oxidation to quinones upon dopamine exposure and its neuroprotective effects against cytotoxicity induced by DA and rotenone. The neuroprotective activity was determined by MTT, LDH and trypan blue or propidium iodide (PI) staining. 

Results: Intraperitoneal injection in mice of ayahuasca extract produced a significant striatal inhibitory effect on MAO A and MAO B activity. In mice striatum of ayahuasca treated mice there is an elevation of dopamine and reduction of the levels of di-hydroxy-phenyl acetic acid (DOPAC), homovanillic acid (HVA) and 5-hydroxy-indole acetic acid (5-HIAA). After ayahuasca administration, the mice display less anxiogenic behavior in marble burying test and less exploratory activities in the open field tests. Results demonstrated no significant antioxidative and neuroprotective effects of ayahuasca on dopamine and rotenone toxicity. 

Conclusion: Ayahuasca extract due its strong inhibitory effect on MAO A activity and more powerful inhibition of MAO B, and absence of toxicity could be used as an alternative or complementary therapy for the treatment of Parkinson´s disease.

Perucho, J., Alarcón, F., Mena, M. Á., de Yebenes, J. G., & Casarejos, M. J. Is Ayahuasca a Potential Ethnic Plant for the Treatment of Parkinson’s Disease?.
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The Nucleus Accumbens and Ketamine Treatment in Major Depressive Disorder

Abstract

Animal models of depression repeatedly showed stress-induced nucleus accumbens (NAc) hypertrophy. Recently, ketamine was found to normalize this stress-induced NAc structural growth. Here, we investigated NAc structural abnormalities in major depressive disorder (MDD) in two cohorts. Cohort A included a cross-sectional sample of 34 MDD and 26 healthy control (HC) subjects, with high-resolution magnetic resonance imaging (MRI) to estimate NAc volumes. Proton MR spectroscopy (1H MRS) was used to divide MDD subjects into two subgroups: glutamate-based depression (GBD) and non-GBD. A separate longitudinal sample (cohort B) included 16 MDD patients who underwent MRI at baseline then 24 h following intravenous infusion of ketamine (0.5 mg/kg). In cohort A, we found larger left NAc volume in MDD compared to controls (Cohen’s d=1.05), but no significant enlargement in the right NAc (d=0.44). Follow-up analyses revealed significant subgrouping effects on the left (d⩾1.48) and right NAc (d⩾0.95) with larger bilateral NAc in non-GBD compared to GBD and HC. NAc volumes were not different between GBD and HC. In cohort B, ketamine treatment reduced left NAc, but increased left hippocampal, volumes in patients achieving remission. The cross-sectional data provided the first evidence of enlarged NAc in patients with MDD. These NAc abnormalities were limited to patients with non-GBD. The pilot longitudinal data revealed a pattern of normalization of left NAc and hippocampal volumes particularly in patients who achieved remission following ketamine treatment, an intriguing preliminary finding that awaits replication.
Abdallah, C. G., Jackowski, A., Salas, R., Gupta, S., Sato, J. R., Mao, X., … & Mathew, S. J. (2017). The nucleus accumbens and ketamine treatment in major depressive disorder. Neuropsychopharmacology1, 8. 10.1038/npp.2017.49
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Ketamine as a Rapid-Acting Antidepressant: Promising Clinical and Basic Research

Abstract

Suicidal ideation and attempts are a common medical emergency, accounting for about 650,000 adult evaluations per year in emergency settings (1). Depressive disorders are a major driving force behind this, but first-line antidepressants, such as selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs), can take months to work, making them of limited use in acutely suicidal patients. Potentially safe and fast-acting interventions would be invaluable in acute situations until standard antidepressants have time to take effect.
Ketamine, best known as an N-methyl-d-aspartate receptor (NMDAR) antagonist commonly used as an anesthetic, has recently drawn attention for possibly filling the role. At lower doses it exhibits strong antidepressant effects in many patients, and it acts on the order of minutes. Despite these promising effects, its use as an antidepressant has been controversial, as ketamine is also a Schedule III controlled substance that is used recreationally for its dissociative and hallucinogenic effects. Furthermore, the full mechanism of action regarding its antidepressant effects has long remained unclear.
In the present article, we review research surrounding ketamine’s potential as a fast-acting antidepressant from a “two-pronged” approach: first, summarizing established and new knowledge on its mechanism of action and second, reviewing clinical research addressing its potential to quickly reduce depression and suicidality.
Tuck, A. N., & Ghazali, D. H. (2017). Ketamine as a Rapid-Acting Antidepressant: Promising Clinical and Basic Research. American Journal of Psychiatry Residents’ Journal12(3), 3-5. 10.1176/appi.ajp-rj.2017.120302
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Psychedelics and the science of self-experience

Abstract

Altered self-experiences arise in certain psychiatric conditions, and may be induced by psychoactive drugs and spiritual/religious practices. Recently, a neuroscience of self-experience has begun to crystallise, drawing upon findings from functional neuroimaging and altered states of consciousness occasioned by psychedelic drugs. This advance may be of great importance for psychiatry.

Nour, M. M., & Carhart-Harris, R. L. (2017). Psychedelics and the science of self-experience. 10.1192/bjp.bp.116.194738
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Synthesis of New Harmine Isoxazoles and Evaluation of their Potential Anti-Alzheimer, Anti-inflammatory, and Anticancer Activities

Abstract

Harmine 1 was extracted from the seeds of Peganum harmala. From this natural molecule, a new series of isoxazole derivatives with complete regiospecificity were prepared using 1,3-dipolar cycloaddition reactions with various arylnitrile oxides. Harmine and its derivatives were characterized by (1)H NMR, (13)C NMR and HRMS. The evaluation of their anti-acetylcholinesterase (AChE), anti-5-lipoxygenase (5-LOX), anti-xanthine oxidase (XOD) and anticancer activities were studied in vitro against AChE, 5-LOX and XOD enzymes, respectively, and in HTC-116, MCF7 and OVCAR-3 cancer cell lines. The prepared derivatives were shown to be inactive against the XOD enzyme (0-38.3 ± 1.9% at 100 µM). Compound 2 exhibited the best anti-AChE activity (IC50=1.9 ± 1.5 µM). Derivatives 3a, 3b and 3d had moderate cytotoxic activities (IC50=5.0 ± 0.3 µM (3a) and IC50=6.3 ± 0.4 µM (3b) against HCT 116 cells, IC50=5.0 ± 1.0 µM (3d) against MCF7 cells).

Filali, I., Romdhane, A., Znati, M., B Jannet, H., & Bouajila, J. (2016). Synthesis of New Harmine Isoxazoles and Evaluation of their Potential Anti-Alzheimer, Anti-inflammatory, and Anticancer Activities. Medicinal Chemistry, 12(2), 184-190. 10.2174/157340641202160209104115
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Indole Alkaloids from Plants as Potential Leads for Antidepressant Drugs: A Mini Review

Abstract

Depression is the most common illness observed in the elderly, adults, and children. Antidepressants prescribed are usually synthetic drugs and these can sometimes cause a wide range of unpleasant side effects. Current research is focussed on natural products from plants as they are a rich source of potent new drug leads. Besides Hypericum perforatum (St. John’s wort), the plants studied include Passiflora incarnata L. (passion flower), Mitragyna speciosa (kratom), Piper methysticum G. Forst (kava) and Valeriana officinalis L. Harman, harmol, harmine, harmalol and harmaline are indole alkaloids isolated from P. incarnata, while mitragynine is isolated from M. speciosa. The structure of isolated compounds from P. methysticum G. Forst and V. officinalis L. contains an indole moiety. The indole moiety is related to the neurotransmitter serotonin which is widely implicated for brain function and cognition as the endogenous receptor agonist. An imbalance in serotonin levels may influence mood in a way that leads to depression. The moiety is present in a number of antidepressants already on the market. Hence, the objective of this review is to discuss bioactive compounds containing the indole moiety from plants that can serve as potent antidepressants.

Hamid, H. A., Ramli, A. N., & Yusoff, M. M. (2017). Indole Alkaloids from Plants as Potential Leads for Antidepressant Drugs: A Mini Review. Frontiers in Pharmacology, 8, 96. 10.3389/fphar.2017.00096
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Effects of Hallucinogens on Neuronal Activity

Abstract

Hallucinogens evoke sensory, perceptual, affective, and cognitive effects that may be useful to understand the neurobiological basis of mood and psychotic disorders. The present chapter reviews preclinical research carried out in recent years in order to better understand the action of psychotomimetic agents such as the noncompetitive NMDA receptor (NMDA-R) antagonists and serotonergic hallucinogens. Our studies have focused on the mechanisms through which these agents alter cortical activity. Noncompetitive NMDA-R antagonists, such as phencyclidine (PCP) and MK-801 (dizocilpine), as well as the serotonergic hallucinogens DOI and 5-MeO-DMT, produce similar effects on cellular and population activity in prefrontal cortex (PFC); these effects include alterations of pyramidal neuron discharge (with an overall increase in firing), as well as a marked attenuation of the low frequency oscillations (0.2–4 Hz) to which neuronal discharge is coupled in anesthetized rodents. PCP increases cfos expression in excitatory neurons from various cortical and subcortical areas, particularly the thalamus. This effect of PCP involves the preferential blockade of NMDA-R on GABAergic neurons of the reticular nucleus of the thalamus, which provides feedforward inhibition to the rest of thalamic nuclei. It is still unknown whether serotonergic hallucinogens also affect thalamocortical networks. However, when examined, similar alterations in other cortical areas, such as the primary visual cortex (V1), have been observed, suggesting that these agents affect cortical activity in sensory and associative areas. Interestingly, the disruption of PFC activity induced by PCP, DOI and 5-MeO-DMT is reversed by classical and atypical antipsychotic drugs. This effect suggests a possible link between the mechanisms underlying the disruption of perception by multiple classes of hallucinogenic agents and the therapeutic efficacy of antipsychotic agents.

Lladó-Pelfort, L., Celada, P., Riga, M. S., Troyano-Rodríguez, E., Santana, N., & Artigas, F. (2017). Effects of Hallucinogens on Neuronal Activity. 10.1007/7854_2017_473

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Hallucinogenic Drugs: A New Study Answers Old Questions about LSD.

Abstract

LSD induces profound psychedelic effects, including changes in the meaning of percepts. The subjective effects of LSD are fully blocked by a 5-HT2A receptor antagonist. LSD may alter meaningfulness by increasing activity in cortical regions responsible for processing personal attribution.

Halberstadt, A. L. (2017). Hallucinogenic drugs: A new study answers old questions about LSD. Current Biology27(4), R156-R158., https://doi.org/10.1016/j.cub.2016.12.058
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22-azidosalvinorin A exhibits antidepressant-like effect in mice

Abstract

The increasing cases of depression has made the searches for new drugs and understanding of the underligning neurobiology of this psychiatric disorder a necessity. Here, we modified the structure of salvinorin A (a known halucinogen) and investigated antidepressant-like activity of its four derivatives; 22-methylsulfanylsalvinorin A(SA1), 2-O-cinnamoylsalvinorin B (CSB), 22-azidosalvinorin A (SA2), and 2-O-(4-azidophenylsulfonyl)salvinorin B (SA3). Prior to behavioural tests (Irwin test, open field test – OFT, forced swimming test – FST and tail suspension test – TST), SA1 was prepared by reacting salvinorin B and methylthioacetic acid with 89% yield; CSB was obtained from the reaction of salvinorin B and cinnamic acid with 92% yield; SA2 was obtained from the reaction of salvinorin B and azidoacetic acid with 81% yield; and SA3 was prepared by reacting salvinorin B with 4-azidophenylsulfonyl chloride with 80% yield. Oral treatment of mice with these derivatives (1–1000 mg/kg) did not elicit toxic sign or death. Unlike SA, SA1, CSB and SA3, treatment with SA2 (5, 10 and 20 mg/kg) decreased the immobility (TST and FST) and swimming time (FST) without altering locomotor activity in OFT. A decrease in the immobility time in TST and FST confirmed antidepressant-like property of SA2. Although p-chlorophenylalanine (serotonin depletor) or WAY100635 (selective 5-HT1A receptor antagonist) did not attenuate effect of SA2, alpha-methyl-para-tyrosine (catecholamine depletor) and prazosin (selective α1-receptor antagonist) attenuated this effect. SA2 mildly inhibited monoamine oxidase and showed affinity for α1A, α1B, α1D and κ-opioid receptor subtypes. In summary, SA2 induced monoamine-mediated antidepressant-like effect.

Fajemiroye, J. O., Prabhakar, P. R., da Cunha, C. L., Costa, E. A., & Zjawiony, J. K. (2017). 22-Azidosalvinorin A exhibits antidepressant-like effect in mice. European Journal of Pharmacology. 10.1016/j.ejphar.2017.02.031
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Altered Insula Connectivity Under MDMA

Abstract

Recent work with noninvasive human brain imaging has started to investigate the effects of 3, 4-methylenedioxymethamphetamine (MDMA) on large-scale patterns of brain activity. MDMA, a potent monoamine-releaser with particularly pronounced serotonin- releasing properties, has unique subjective effects that include: marked positive mood, pleasant/unusual bodily sensations and pro-social, empathic feelings. However, the neurobiological basis for these effects is not properly understood, and the present analysis sought to address this knowledge gap. To do this, we administered MDMA-HCl (100 mg p.o.) and, separately, placebo (ascorbic acid) in a randomized, double-blind, repeated-measures design with twenty-five healthy volunteers undergoing fMRI scanning. We then employed a measure of global resting-state functional brain connectivity and follow-up seed-to-voxel analysis to the fMRI data we acquired. Results revealed decreased right insula/salience network functional connectivity under MDMA. Furthermore, these decreases in right insula/salience network connectivity correlated with baseline trait anxiety and acute experiences of altered bodily sensations under MDMA. The present findings highlight insular disintegration (ie, compromised salience network membership) as a neurobiological signature of the MDMA experience, and relate this brain effect to trait anxiety and acutely altered bodily sensations-both of which are known to be associated with insular functioning.

Walpola, I. C., Nest, T., Roseman, L., Erritzoe, D., Feilding, A., Nutt, D. J., & Carhart-Harris, R. L. (2017). Altered Insula Connectivity Under MDMA. Neuropsychopharmacology: official publication of the American College of Neuropsychopharmacology. 10.1038/npp.2017.35
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