Psychopharmacology
February 22, 2001
Jordi Riba, Antoni Rodrı́guez-fornells, Gloria Urbano et al.
302 citations
Ayahuasca, a South American psychoactive beverage containing DMT, produced dose-dependent psychological effects in six healthy male volunteers with prior experience. Encapsulated freeze-dried ayahuasca at doses of 0.5, 0.75, and 1.0 mg DMT/kg body weight increased scores on hallucinogen rating scales, addiction research inventory scales, and visual analogue scales for liking, good effects, and high. Effects began within 30-60 minutes, peaked at 60-120 minutes, and resolved by 240 minutes. The tea was well tolerated cardiovascularly, though nausea and altered physical sensations were common. Five volunteers found the experience pleasant; one had an intensely dysphoric reaction with anxiety and withdrew. Ayahuasca induced perceptual, affective, cognitive, and somatic changes of longer duration and milder intensity than intravenous DMT.
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.
Psychopharmacology
June 20, 2013
José Carlos Bouso, Josep María Fábregas, Rosa María Antonijoan et al.
96 citations
Acute ayahuasca intake impaired working memory, as measured by increased errors on the Sternberg task, but reduced stimulus-response interference, shown by faster reaction times on the Stroop task with maintained accuracy. Performance on the Tower of London task, which assesses executive function, worsened only in occasional users, not in long-term experienced users. Greater lifetime ayahuasca use was associated with less impairment on the Tower of London. The findings suggest that prior exposure to ayahuasca may protect against acute cognitive disruption, possibly due to compensatory or neuromodulatory effects.
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.
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.
The international journal of neuropsychopharmacology
January 12, 2022
Genís Ona, Frederic Sampedro, Sergio Romero et al.
17 citations
Kappa opioid receptor (KOR) agonists like salvinorin-A produce psychotomimetic effects through largely unknown mechanisms. In a double-blind, crossover, randomized, placebo-controlled study, acute administration of salvinorin-A increased delta and gamma brain waves while decreasing alpha waves, as measured by electroencephalography. Single-photon emission computed tomography revealed significant decreases in regional cerebral blood flow across frontal, temporal, parietal, and occipital cortices, with increases in the medial temporal lobe, amygdala, hippocampal gyrus, and cerebellum. Subjective effects resembled other psychotomimetic drugs but were distinctly dissociative, with no dysphoria reported. KOR agonism by salvinorin-A induces dramatic psychotomimetic effects alongside generalized reductions in cortical blood flow and electrical activity.