Topographic pharmaco-EEG mapping of the effects of the South American psychoactive beverage ayahuasca in healthy volunteers.
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AIMS: Ayahuasca is a traditional South American psychoactive beverage used in Amazonian shamanism, and in the religious ceremonies of Brazilian-based syncretic religious groups with followers in the US and several European countries. This tea contains measurable amounts of the psychotropic indole N,N-dimethyltryptamine (DMT), and beta-carboline alkaloids with MAO-inhibiting properties. In a previous report we described a profile of stimulant and psychedelic effects for ayahuasca as measured by subjective report self-assessment instruments. In the present study the cerebral bioavailability and time-course of effects of ayahuasca were assessed in humans by means of topographic quantitative-electroencephalography (q-EEG), a noninvasive method measuring drug-induced variations in brain electrical activity. METHODS: Two doses (one low and one high) of encapsulated freeze-dried ayahuasca, equivalent to 0.6 and 0.85 mg DMT kg(-1) body weight, were administered to 18 healthy volunteers with previous experience in psychedelic drug use in a double-blind crossover placebo-controlled clinical trial. Nineteen-lead recordings were undertaken from baseline to 8 h after administration. Subjective effects were measured by means of the Hallucinogen Rating Scale (HRS). RESULTS: Ayahuasca induced a pattern of psychoactive effects which resulted in significant dose-dependent increases in all subscales of the HRS, and in significant and dose-dependent modifications of brain electrical activity. Absolute power decreased in all frequency bands, most prominently in the theta band. Mean absolute power decreases (95% CI) at a representative lead (P3) 90 min after the high dose were -20.20+/-15.23 microV2 and -2.70+/-2.21 microV2 for total power and theta power, respectively. Relative power decreased in the delta (-1.20+/-1.31% after 120 min at P3) and theta (-3.30+/-2.59% after 120 min at P3) bands, and increased in the beta band, most prominently in the faster beta-3 (1.00+/-0.88% after 90 min at P3) and beta-4 (0.30+/-0.24% after 90 min at P3) subbands. Finally, an increase was also seen for the centroid of the total activity and its deviation. EEG modifications began as early as 15-30 min, reached a peak between 45 and 120 min and decreased thereafter to return to baseline levels at 4-6 h after administration. CONCLUSIONS: The central effects of ayahuasca could be objectively measured by means of q-EEG, showing a time pattern which closely paralleled that of previously reported subjective effects. The modifications seen for the individual q-EEG variables were in line with those previously described for other serotonergic psychedelics and share some features with the profile of effects shown by pro-serotonergic and pro-dopaminergic drugs. The q-EEG profile supports the role of 5-HT2 and dopamine D2-receptor agonism in mediating the effects of ayahuasca on the central nervous system. (+info)
Human pharmacology of ayahuasca: subjective and cardiovascular effects, monoamine metabolite excretion, and pharmacokinetics.
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The effects of the South American psychotropic beverage ayahuasca on subjective and cardiovascular variables and urine monoamine metabolite excretion were evaluated, together with the drug's pharmacokinetic profile, in a double-blind placebo-controlled clinical trial. This pharmacologically complex tea, commonly obtained from Banisteriopsis caapi and Psychotria viridis, combines N,N-dimethyltryptamine (DMT), an orally labile psychedelic agent showing 5-hydroxytryptamine2A agonist activity, with monoamine oxidase (MAO)-inhibiting beta-carboline alkaloids (harmine, harmaline, and tetrahydroharmine). Eighteen volunteers with prior experience in the use of psychedelics received single oral doses of encapsulated freeze-dried ayahuasca (0.6 and 0.85 mg of DMT/kg of body weight) and placebo. Ayahuasca produced significant subjective effects, peaking between 1.5 and 2 h, involving perceptual modifications and increases in ratings of positive mood and activation. Diastolic blood pressure showed a significant increase at the high dose (9 mm Hg at 75 min), whereas systolic blood pressure and heart rate were moderately and nonsignificantly increased. Cmax values for DMT after the low and high ayahuasca doses were 12.14 ng/ml and 17.44 ng/ml, respectively. Tmax (median) was observed at 1.5 h after both doses. The Tmax for DMT coincided with the peak of subjective effects. Drug administration increased urinary normetanephrine excretion, but, contrary to the typical MAO-inhibitor effect profile, deaminated monoamine metabolite levels were not decreased. This and the negligible harmine plasma levels found suggest a predominantly peripheral (gastrointestinal and liver) site of action for harmine. MAO inhibition at this level would suffice to prevent first-pass metabolism of DMT and allow its access to systemic circulation and the central nervous system. (+info)
A fatal intoxication following the ingestion of 5-methoxy-N,N-dimethyltryptamine in an ayahuasca preparation.
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A case of a 25-year-old white male who was found dead the morning after consuming herbal extracts containing beta-carbolines and hallucinogenic tryptamines is presented. No anatomic cause of death was found at autopsy. Toxicologic analysis of the heart blood identified N,N-dimethyltryptamine (0.02 mg/L), 5-methoxy-N,N-dimethyltryptamine (1.88 mg/L), tetrahydroharmine (0.38 mg/L), harmaline (0.07 mg/L), and harmine (0.17 mg/L). All substances were extracted by a single-step n-butyl chloride extraction following alkalinization with borate buffer. Detection and quantitation was performed using liquid chromatography-electrospray mass spectrometry. The medical examiner ruled that the cause of death was hallucinogenic amine intoxication, and the manner of death was undetermined. (+info)
Ayahuasca versus violence--a case report.
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We have limited resources available for the treatment and prevention of violent behavior. The usefulness of the most commonly used medications, namely the selective serotonin-reuptake inhibitor [SSRI] agents for the above purpose is a debated issue in the psychiatric literature. The aim of this case report is to add an ethnopharmacological perspective to the management of human aggression. Particularly, attention is called to the potential prosocial effect of the Amazonian beverage, ayahuasca--a decoctum, which has been used traditionally for multiple medico-religious purposes by numerous indigenous groups of the Upper Amazon--and has been found to be useful in crisis intervention, achieving redemption, as well as eliciting cathartic feelings with moral content. (+info)
Banisteriopsis caapi, a unique combination of MAO inhibitory and antioxidative constituents for the activities relevant to neurodegenerative disorders and Parkinson's disease.
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Composition, standardization and chemical profiling of Banisteriopsis caapi, a plant for the treatment of neurodegenerative disorders relevant to Parkinson's disease.
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