Universität Zürich, ZORA
June 1, 2026
Klemens Egger, Robert Bozsak, Helena Aicher et al.
Classical psychedelics such as N,N -dimethyltryptamine (DMT) modulate consciousness via serotonergic receptor agonism, and are increasingly investigated for their psychotherapeutic potential. When combined with the monoamine oxidase A (MAO-A) inhibitor harmine—mimicking the pharmacological profile of ayahuasca—oral DMT induces a psychedelic experience lasting 4–5 h. While some neuroimaging...
Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism
June 1, 2026
Klemens Egger, Robert Bozsak, Helena Aicher et al.
Classical psychedelics such as N,N-dimethyltryptamine (DMT) modulate consciousness via serotonergic receptor agonism, and are increasingly investigated for their psychotherapeutic potential. When combined with the monoamine oxidase A (MAO-A) inhibitor harmine-mimicking the pharmacological profile of ayahuasca-oral DMT induces a psychedelic experience lasting 4-5 h. While some neuroimaging...
Open Access CRIS of the University of Bern
February 9, 2026
Mikael Palner, Elisabeth Kolesnik, Christina Baun et al.
Mammalian brain may contain an endogenous pool of the psychedelic substance N,N-dimethyltryptamine (DMT), which may act as a co-transmitter with serotonin (5-HT). We tested the joint hypotheses. We tested the joint hypotheses that endogenous DMT would accumulate in rat brain after inhibiting monoamine oxidase with pargyline, whereas its acidic metabolite 3-indoleacetic acid (3-IAA) would...
Neuropharmacology
February 9, 2026
Mikael Palner, Elisabeth Kolesnik, Christina Baun et al.
Mammalian brain may contain an endogenous pool of the psychedelic substance N,N-dimethyltryptamine (DMT), which may act as a co-transmitter with serotonin (5-HT). We tested the joint hypotheses. We tested the joint hypotheses that endogenous DMT would accumulate in rat brain after inhibiting monoamine oxidase with pargyline, whereas its acidic metabolite 3-indoleacetic acid (3-IAA) would...
Repository for Publications and Research Data (ETH Zurich)
2026
Klemens Egger, Robert Bozsak, Helena Aicher et al.
Classical psychedelics such as N,N-dimethyltryptamine (DMT) modulate consciousness via serotonergic receptor agonism, and are increasingly investigated for their psychotherapeutic potential. When combined with the monoamine oxidase A (MAO-A) inhibitor harmine—mimicking the pharmacological profile of ayahuasca—oral DMT induces a psychedelic experience lasting 4–5 h. While some neuroimaging...
Research Square
July 27, 2025
Klemens Egger, Robert Bozsak, Helena Aicher et al.
1 citation
Global Increases in Brain Glucose Metabolism Following Acute N,N-Dimethyltryptamine and Harmine Administration in Healthy Volunteers: An [¹⁸F]FDG-PET Study
International review of neurobiology
2025
Paul Cumming, Klemens Egger, Gitte M. Knudsen
2 citations
Molecular brain imaging by positron emission tomography (PET) and single photon emission computer-tomography (SPECT) entails the mapping of the cerebral distribution of radiopharmaceuticals that track physiological processes such as blood perfusion and glucose metabolism, or the abundance in brain of specific molecular targets such as neuroreceptors. PET and SPECT emerged as useful in vivo...
Cellular and molecular life sciences : CMLS
September 10, 2024
Klemens Egger, Helena Aicher, Paul Cumming et al.
30 citations
The potent hallucinogen N,N-dimethyltryptamine (DMT) has garnered significant interest in recent years due to its profound effects on consciousness and its therapeutic psychopotential. DMT is an integral (but not exclusive) psychoactive alkaloid in the Amazonian plant-based brew ayahuasca, in which admixture of several β-carboline monoamine oxidase A (MAO-A) inhibitors potentiate the activity...
Molecular Psychiatry
September 1, 2023
Kat F. Kiilerich, Joe Lorenz, Malthe B. Scharff et al.
48 citations
Psilocybin (a classic serotonergic psychedelic drug) has received appraisal for use in psychedelic-assisted therapy of several psychiatric disorders. A less explored topic concerns the use of repeated low doses of psychedelics, at a dose that is well below the psychedelic dose used in psychedelic-assisted therapy and often referred to as microdosing. Psilocybin microdose users frequently report...
January 4, 2023
Klemens Egger, Frederik Gudmundsen, Naja Støckel Jessen et al.
preprint
RationaleThe psychedelic effects of the traditional Amazonian botanical decoction known as ayahuasca are attributed to the effects of N,N-dimethyltryptamine (DMT) at brain serotonin 5-HT2A receptors. To make oral DMT bioavailable, ayahuasca additionally contains reversible monoamine oxidase A (MAO-A) inhibitors, namely β-carboline alkaloids such as harmine. However, there is lacking biochemical...
Frontiers in Pharmacology
2023
Klemens Egger, Frederik Gudmundsen, Naja Støckel Jessen et al.
17 citations
Rationale: The psychedelic effects of the traditional Amazonian botanical decoction known as ayahuasca are often attributed to agonism at brain serotonin 5-HT2A receptors by N,N-dimethyltryptamine (DMT). To reduce first pass metabolism of oral DMT, ayahuasca preparations additionally contain reversible monoamine oxidase A (MAO-A) inhibitors, namely β-carboline alkaloids such as harmine....
Frontiers in Pharmacology
May 2, 2022
Ilana Berlowitz, Klemens Egger, Paul Cumming
32 citations
The monoamine oxidases (MAOs) are flavin-containing amine oxidoreductases responsible for metabolism of many biogenic amine molecules in the brain and peripheral tissues. Whereas serotonin is the preferred substrate of MAO-A, phenylethylamine is metabolized by MAO-B, and dopamine and tyramine are nearly ambivalent with respect to the two isozymes. β-Carboline alkaloids such as harmine,...
Molecules
April 22, 2021
Paul Cumming, Milan Scheidegger, Dario Dornbierer et al.
45 citations
Hallucinogens are a loosely defined group of compounds including LSD, N,N-dimethyltryptamines, mescaline, psilocybin/psilocin, and 2,5-dimethoxy-4-methamphetamine (DOM), which can evoke intense visual and emotional experiences. We are witnessing a renaissance of research interest in hallucinogens, driven by increasing awareness of their psychotherapeutic potential. As such, we now present a...
Neuropsychopharmacology
March 3, 2021
Nora Penzel, Linda A. Antonucci, Linda T. Betz et al.
18 citations
Cannabis use during adolescence is associated with an increased risk of developing psychosis. According to a current hypothesis, this results from detrimental effects of early cannabis use on brain maturation during this vulnerable period. However, studies investigating the interaction between early cannabis use and brain structural alterations hitherto reported inconclusive findings. We...
Synapse
April 5, 2007
Paul Cumming, Mette Møller, Kjeld Benda et al.
28 citations
Abstract The psychostimulant 3,4‐methylendioxymethamphetamine (MDMA, “ecstasy”) evokes degeneration of telencephalic serotonin innervations in rodents, nonhuman primates, and human recreational drug users. However, there has been no alternative to nonhuman primates for studies of the cognitive and neurochemical consequences of serotonin depletion in a large‐bodied animal. Therefore, we used...
Synapse
2005
Luciano Minuzzi, George G. Nomikos, Mark Wade et al.
25 citations
The psychoactive properties of the hallucinogen LSD have frequently been attributed to high affinity interactions with serotonin 5HT2 receptors in brain. Possible effects of LSD on dopamine D2/3 receptor availability have not previously been investigated in living brain. Therefore, we used PET to map the binding potential (pB) of [11C]raclopride in brain of three pigs, first in a baseline...
Synapse
July 14, 2004
Pedro Rosa‐neto, Albert Gjedde, Aage Kristian Olsen Alstrup et al.
39 citations
Abstract Positron emission tomography (PET) studies with radiolabeled dopamine D 2 ‐like receptor ligands reveal d ‐amphetamine‐evoked increases in the competition from endogenous dopamine. However, the corresponding effects of methylenedioxymethamphetamine (MDMA, “Ecstasy”), which releases catecholamines and also serotonin, are unknown. Using PET, we measured the binding potentials ( pB s) of...