R Zurich, University of Zurich and Swiss Federal Institute of Technology Zurich, CH-8058 Zurich, Switzerland

R Zurich, University of Zurich and Swiss Federal Institute of Technology Zurich, CH-8058 Zurich, Switzerland Division of Psychology, University of Fribourg, CH-1700 Fribourg, Switzerland; chantal.martinsoelch@unifr.ch Correspondence: [email protected] or [email protected]: Cumming, P.; Scheidegger, M.; Dornbierer, D.; Palner, M.; Quednow, B.B.; Martin-Soelch, C. Molecular and Functional TXA2/TP Molecular Weight imaging Research of Psychedelic Drug Action in Animals and Humans. Molecules 2021, 26, 2451. https://doi.org/10.3390/ molecules26092451 Academic Editors: Mauricio Morais and P er Kele Received: eight March 2021 Accepted: 19 April 2021 Published: 22 AprilPublisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.Copyright: 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is definitely an open access post distributed under the terms and situations with the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ four.0/).DNA Methyltransferase Inhibitor Accession Abstract: Hallucinogens are a loosely defined group of compounds like LSD, N,Ndimethyltryptamines, mescaline, psilocybin/psilocin, and 2,5-dimethoxy-4-methamphetamine (DOM), which can evoke intense visual and emotional experiences. We are witnessing a renaissance of investigation interest in hallucinogens, driven by rising awareness of their psychotherapeutic prospective. As such, we now present a narrative overview from the literature on hallucinogen binding in vitro and ex vivo, and also the a variety of molecular imaging studies with positron emission tomography (PET) or single photon emission laptop tomography (SPECT). In general, molecular imaging can depict the uptake and binding distribution of labelled hallucinogenic compounds or their congeners within the brain, as was shown in an early PET study with N1 -([11 C]-methyl)-2-bromo-LSD ([11 C]-MBL); displacement together with the non-radioactive competitor ketanserin confirmed that the majority of [11 C]-MBL specific binding was to serotonin 5-HT2A receptors. Having said that, interactions at serotonin 5HT1A and also other classes of receptors and pleotropic effects on second messenger pathways may well contribute to the particular experiential phenomenologies of LSD along with other hallucinogenic compounds. Other salient aspects of hallucinogen action contain permeability towards the blood rain barrier, the rates of metabolism and elimination, along with the formation of active metabolites. In spite of the maturation of radiochemistry and molecular imaging in recent years, there has been only a handful of PET or SPECT studies of radiolabeled hallucinogens, most lately employing the 5-HT2A/2C agonist N-(2[11 CH3 O]methoxybenzyl)-2,5-dimethoxy- 4-bromophenethylamine ([11 C]Cimbi-36). In addition to PET research of target engagement at neuroreceptors and transporters, there is a modest number of studies around the effects of hallucinogenic compounds on cerebral perfusion ([15 O]-water) or metabolism ([18 F]fluorodeoxyglucose/FDG). There remains considerable scope for standard imaging analysis on the websites of interaction of hallucinogens and their cerebrometabolic effects; we expect that hybrid imaging with PET in conjunction with functional magnetic resonance imaging (fMRI) should offer in particular valuable for the subsequent phase of this analysis. Keywords: hallucinogens; molecular imaging; PET; SPECT; serotonin receptorsMolecules 2021, 26, 2451. https://doi.org/10.3390/moleculeshttps://www.mdpi.com/journal/moleculesMolecules 2021, 26,two ofContents: 1.