Acute Biphasic Effects of Ayahuasca
This study examines the effects of ayahuasca on brain activity with respect to the temporal metabolism of its active compounds and found that DMT (97.3mg/70kg) and harmine (320.6mg/70kg) are related to the early phase of the experience, measured as reduced power in the alpha band after 50 minutes, while harmaline (52.5mg/70kg) and tetrahydroharmine (380.1mg/70kg) are more strongly associated with the later phase of the experience, measured as gamma-band increases after 75 minutes from ingestion. The present results reveal acute biphasic effects of ayahuasca in the brain.
Authors
- Suresh Muthukumaraswamy
- Mariana Yonamine
- Draulio Silveira
Published
Abstract
Introduction
Ritual use of ayahuasca, an amazonian Amerindian medicine turned sacrament in syncretic religions in Brazil, is rapidly growing around the world. Because of this internationalization, a comprehensive understanding of the pharmacological mechanisms of action of the brew and the neural correlates of the modified states of consciousness it induces is important.Methods/Results: Employing a combination of electroencephalogram (EEG) recordings and quantification of ayahuasca's compounds and their metabolites in the systemic circulation we found ayahuasca to induce a biphasic effect in the brain. This effect was composed of reduced power in the alpha band (8-13 Hz) after 50 minutes from ingestion of the brew and increased slow- and fast-gamma power (30-50 and 50-100 Hz, respectively) between 75 and 125 minutes. Alpha power reductions were mostly located at left parieto-occipital cortex, slow-gamma power increase was observed at left centro-parieto-occipital, left fronto-temporal and right frontal cortices while fast-gamma increases were significant at left centro-parieto-occipital, left fronto-temporal, right frontal and right parieto-occipital cortices. These effects were significantly associated with circulating levels of ayahuasca’s chemical compounds, mostly N,N-dimethyltryptamine (DMT), harmine, harmaline and tetrahydroharmine and some of their metabolites.
Discussion
An interpretation based on a cognitive and emotional framework relevant to the ritual use of ayahuasca, as well as it's potential therapeutic effects is offered.
Research Summary of 'Acute Biphasic Effects of Ayahuasca'
Introduction
Ayahuasca is an Amazonian plant brew containing beta-carbolines (harmine, harmaline, tetrahydroharmine or THH) and the psychedelic tryptamine DMT. Earlier pharmacological work established that the beta-carbolines act as monoamine-oxidase A (MAO-A) inhibitors in the periphery, enabling orally ingested DMT to reach the brain, and prior neurophysiological studies using EEG have reported a mixture of findings including alpha decreases, theta/delta changes, beta increases and occasional reports of gamma-band effects. These prior studies varied in setting (ritual versus laboratory), timing after ingestion, dose regimens and the use of lyophilised versus liquid preparations, leaving unresolved questions about the temporal dynamics and pharmacological correlates of ayahuasca's effects on brain oscillations. Schenberg and colleagues therefore set out to record continuous EEG alongside repeated plasma sampling after a standardised dose of liquid ayahuasca in experienced volunteers in a controlled laboratory setting. The principal aim was to characterise the time course of oscillatory changes across frequency bands and to relate these changes to circulating concentrations of DMT, beta-carbolines and metabolites, thereby clarifying whether distinct early and late electrophysiological phases of the ayahuasca experience exist and which compounds are associated with each phase. The study combines spectral EEG analysis with pharmacokinetic measures to investigate neural and pharmacological correlates of the acute ayahuasca state.
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Study Details
- Study Typeindividual
- Journal
- Compound
- Topics
- Authors
- APA Citation
Schenberg, E. E., Alexandre, J. F. M., Filev, R., Cravo, A. M., Sato, J. R., Muthukumaraswamy, S. D., Yonamine, M., Waguespack, M., Lomnicka, I., Barker, S. A., & da Silveira, D. X. (2015). Acute Biphasic Effects of Ayahuasca. PLOS ONE, 10(9), e0137202. https://doi.org/10.1371/journal.pone.0137202
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