Psychopharmacology
November 27, 2015
Joaquim Soler, Matilde Elices, Alba Franquesa et al.
212 citations
Ayahuasca, a psychotropic plant tea containing DMT and β-carboline alkaloids, increases mindfulness capacities within 24 hours of a single session. In 25 individuals, ayahuasca significantly reduced judgmental processing of experiences and inner reactivity, as measured by the Five Facets Mindfulness Questionnaire, and increased decentering ability, as measured by the Experiences Questionnaire. These changes match those seen after extensive mindfulness practice and support the tea's therapeutic potential, particularly for addiction and depression.
The International Journal of Neuropsychopharmacology
May 17, 2017
Frederic Sampedro, Mario de la Fuente Revenga, Marta Valle et al.
205 citations
A single dose of ayahuasca reduced glutamate+glutamine, creatine, and N-acetylaspartate+N-acetylaspartylglutamate in the posterior cingulate cortex of 16 healthy volunteers, measured post-acutely with magnetic resonance spectroscopy. Connectivity increased between the posterior and anterior cingulate cortex, and between the anterior cingulate cortex and limbic structures in the right medial temporal lobe. Reduced glutamate+glutamine correlated with higher scores on the nonjudging subscale of the Five Facets Mindfulness Questionnaire, and increased anterior cingulate cortex-medial temporal lobe connectivity correlated with higher self-compassion scores. Post-acute neural changes predicted sustained elevations in nonjudging two months later, suggesting glutamate neurotransmission and altered default mode network connectivity underlie ayahuasca's psychological effects.
Psychopharmacology
July 19, 2016
Kim P. C. Kuypers, Jordi Riba, Mario de la Fuente Revenga et al.
204 citations
Ayahuasca, a psychedelic plant tea used in Amazonian shamanism, may enhance creative divergent thinking—the ability to generate new ideas and strategies—while decreasing convergent thinking, which focuses on a single correct answer. In a study of 26 participants at two spiritual workshops, creativity tests before and during the acute effects of ayahuasca showed that the tea significantly increased divergent thinking and decreased convergent thinking, as measured by the picture concept test. No significant effects were found on the pattern/line meanings test. These results suggest ayahuasca increases psychological flexibility, potentially aiding psychotherapeutic interventions.
European Neuropsychopharmacology
March 26, 2016
Marta Valle, Ana Maqueda, Mireia Rabella et al.
175 citations
Ayahuasca, a psychoactive Amazonian tea, contains DMT and other compounds. In a double-blind, placebo-controlled study with 12 experienced users, ayahuasca reduced brain oscillations in delta, theta, and alpha frequency bands. The intensity of visual imagery correlated inversely with alpha-band current density in parietal and occipital cortex. Pretreatment with the 5-HT2A antagonist ketanserin blocked these neurophysiological changes, weakened the correlation between alpha activity and visual effects, and reduced subjective intensity. These results indicate that activation of the 5-HT2A receptor is central to ayahuasca's neurophysiological and visual effects in humans, despite the tea's chemical complexity.
Journal of Clinical Psychopharmacology
October 15, 2011
Rafael G. Dos Santos, Marta Valle, José Carlos Bouso et al.
136 citations
Ayahuasca, an Amazonian psychotropic tea containing DMT and β-carboline alkaloids, produced moderate sympathomimetic effects, significant increases in prolactin and cortisol, and time-dependent changes in immune cell populations in a double-blind crossover trial with 10 healthy volunteers. Pupil dilation occurred with both ayahuasca and amphetamine, but ayahuasca’s effects were milder. Prolactin rose only after ayahuasca, while cortisol peaked higher with ayahuasca than with amphetamine. Lymphocyte subsets shifted similarly for both drugs: CD4 and CD3 percentages decreased, and natural killer cells increased, with maximum changes at 2 hours and return to baseline by 24 hours.
PLoS ONE
September 30, 2015
Eduardo Ekman Schenberg, João Felipe Morel Alexandre, Renato Filev et al.
115 citations
Ayahuasca, an Amazonian plant-based brew used ritually in Brazil and increasingly worldwide, produces a two-phase brain effect. Electroencephalogram recordings and blood measurements of the brew's compounds (DMT, harmine, harmaline, tetrahydroharmine, and their metabolites) showed that 50 minutes after ingestion, alpha brainwave power (8–13 Hz) decreased, mostly in the left parieto-occipital cortex. Between 75 and 125 minutes, slow- and fast-gamma power (30–50 and 50–100 Hz, respectively) increased across multiple cortical regions, including left centro-parieto-occipital, left fronto-temporal, and right frontal areas. These brain changes were significantly linked to circulating levels of ayahuasca's active chemicals. The authors interpret these effects within cognitive and emotional frameworks relevant to ritual use and potential therapeutic applications.
International review of neurobiology
January 1, 1981
Steven A. Barker, John A. Monti, Samuel T. Christian
113 citations
No Summary
Drug Testing and Analysis
July 28, 2014
Jordi Riba, Ethan H. Mcilhenny, José Carlos Bouso et al.
96 citations
When N,N-dimethyltryptamine (DMT) is taken orally, it produces no psychedelic effects and no DMT appears in urine, because monoamine oxidase (MAO) breaks it down almost completely into indole-3-acetic acid (97% of recovered compounds). By contrast, smoking DMT yields full psychoactivity, with unmetabolized DMT and DMT-N-oxide rising to 10% and 28% of recovered compounds, while indole-3-acetic acid drops to 63%. An inverse relationship between the ratio of these metabolites and subjective effects indicates that smoking shifts metabolism from efficient MAO-dependent breakdown to less efficient CYP-dependent pathways, enabling psychoactivity.
Drug Testing and Analysis
April 19, 2012
Jordi Riba, Ethan H. Mcilhenny, Marta Valle et al.
91 citations
Ayahuasca, an Amazonian tea containing β-carboline alkaloids (harmine, harmaline, tetrahydroharmine) and the psychedelic DMT, is used worldwide, but its metabolism in humans had not been systematically studied. In 10 healthy men given freeze-dried ayahuasca (1.0 mg DMT/kg), less than 1% of DMT was excreted unchanged; about 50% was recovered as indole-3-acetic acid, 10% as DMT-N-oxide, and total DMT plus metabolites reached 68%. Harmala alkaloids were excreted as O-demethylated and conjugated metabolites, but recoveries varied from 9% to 65%. The findings indicate alternative metabolic routes for DMT beyond monoamine-oxidase and that O-demethylation plus conjugation is important but not the only pathway for harmala alkaloids.
The International Journal of Neuropsychopharmacology
June 5, 2015
Marta Valle, Montserrat Puntes, Jimena Coimbra et al.
75 citations
Salvinorin-A, a compound from the plant Salvia divinorum that activates kappa-opioid receptors, produces dose-dependent changes in perception and body awareness. In eight healthy volunteers with prior psychedelic experience, vaporized salvinorin-A at 0.25, 0.50, and 1 mg caused detachment from external reality, elaborate visions, and auditory phenomena. Lower doses increased bodily sensations, while the highest dose produced a complete loss of contact with the body. The effects on body awareness followed an inverted-U pattern, suggesting the kappa-opioid receptor plays a key role in regulating sensory perception, interoception, and the sense of body ownership.
Biochemical Pharmacology
April 1, 1980
Steven A. Barker, John A. Monti, Samuel T. Christian
72 citations
No Summary
Psychopharmacology
January 22, 2022
Steven A. Barker
59 citations
The route, form, and dose of a drug critically shape its pharmacology and therapeutic use. This review focuses on the psychedelic N,N-dimethyltryptamine (DMT), examining positive and negative aspects of various formulations and routes of administration, including ayahuasca teas, oral "pharmahuasca," intravenous and intramuscular injections, inhalation, insufflation, and high-dose, low-dose, and micro-dose effects. It considers possible oral alternatives that would not require a monoamine oxidase inhibitor. The review also addresses current in vivo and in vitro research findings and the possibility that these findings may reveal a role for endogenous DMT in normal brain function.
The International Journal of Neuropsychopharmacology
February 12, 2016
Marta Valle, Montserrat Puntes, Jimena Coimbra et al.
31 citations
Salvinorin-A, a terpene from the plant Salvia divinorum, induces an intense but short-lasting altered state of awareness similar to classical psychedelics, but it acts on kappa-opioid receptors rather than serotonin-2A receptors. In a double-blind, placebo-controlled study with 24 healthy volunteers experienced with psychedelics, inhalation of 1 mg of vaporized salvinorin-A severely reduced external sensory perception, caused intense visual and auditory modifications, and increased systolic blood pressure, cortisol, and prolactin. These effects were effectively blocked by the opioid antagonist naltrexone (50 mg orally) but not by the serotonin-2A antagonist ketanserin (40 mg orally), confirming that salvinorin-A's mechanism involves kappa-opioid receptor agonism and not serotonin-2A agonism.
Progress in neuro-psychopharmacology & biological psychiatry
March 20, 2025
Steven A. Barker
3 citations
Renewed interest in psychedelic drugs highlights DMT's therapeutic effectiveness and its role as a neuroplastogen. DMT binds to intracellular sigma-1 and 5-HT2a receptors, with the latter located on the Golgi apparatus in cortical neurons, and fails to occupy cell surface 5-HT2a receptors. DMT is proposed as the endogenous ligand for intracellular 5-HT2a receptors, which serotonin cannot access. Brain levels of DMT are elevated by stress in rats and appear under inducible, adaptive physiological regulation. These findings suggest DMT may be involved in brain development and explain subjective effects of psychedelics.