Paul F. Daley

The Designer Methcathinone Analogs, Mephedrone and Methylone, are Substrates for Monoamine Transporters in Brain Tissue

The nonmedical use of ‘designer’ cathinone analogs, such as 4-methylmethcathinone (mephedrone) and 3,4-methylenedioxymethcathinone (methylone), is increasing worldwide, yet little information is available regarding the mechanism of action for these drugs. Here, we employed in vitro and in vivo methods to compare neurobiological effects of mephedrone and methylone with those produced by the structurally related compounds, 3,4-methylenedioxymethamphetamine (MDMA) and methamphetamine. In vitro release assays using rat brain synaptosomes revealed that mephedrone and methylone are nonselective substrates for plasma membrane monoamine transporters, similar to MDMA in potency and selectivity. In vivo microdialysis in rat nucleus accumbens showed that i.v. administration of 0.3 and 1.0 mg/kg of mephedrone or methylone produces dose-related increases in extracellular dopamine and serotonin (5-HT), with the magnitude of effect on 5-HT being greater. Both methcathinone analogs were weak motor stimulants when compared with methamphetamine. Repeated administrations of mephedrone or methylone (3.0 and 10.0 mg/kg, s.c., 3 doses) caused hyperthermia but no long-term change in cortical or striatal amines, whereas similar treatment with MDMA (2.5 and 7.5 mg/kg, s.c., 3 doses) evoked robust hyperthermia and persistent depletion of cortical and striatal 5-HT. Our data demonstrate that designer methcathinone analogs are substrates for monoamine transporters, with a profile of transmitter-releasing activity comparable to MDMA. Dopaminergic effects of mephedrone and methylone may contribute to their addictive potential, but this hypothesis awaits confirmation. Given the widespread use of mephedrone and methylone, determining the consequences of repeated drug exposure warrants further study.

New mescaline concentrations from 14 taxa/cultivars of Echinopsis spp. (Cactaceae) (“San Pedro”) and their relevance to shamanic practice

AIM OF THE STUDY The aim of the present study is to determine in a procedurally uniform manner the mescaline concentrations in stem tissue of 14 taxa/cultivars of the subgenus Trichocereus of the genus Echinopsis (Cactaceae) and to evaluate the relationship (if any) between mescaline concentration and actual shamanic use of these plants. MATERIALS AND METHODS Columnar cacti of the genus Echinopsis, some of which are used for diagnostic and therapeutic purposes by South American shamans in traditional medicine, were selected for analysis because they were vegetative clones of plants of documented geographic origin and/or because they were known to be used by practitioners of shamanism. Mescaline content of the cortical stem chlorenchyma of each cactus was determined by Soxhlet extraction with methanol, followed by acid-base extraction with water and dichloromethane, and high-pressure liquid chromatography (HPLC). RESULTS By virtue of the consistent analytical procedures used, comparable alkaloid concentrations were obtained that facilitated the ranking of the various selected species and cultivars of Echinopsis, all of which exhibited positive mescaline contents. The range of mescaline concentrations across the 14 taxa/cultivars spanned two orders of magnitude, from 0.053% to 4.7% by dry weight. CONCLUSIONS The mescaline concentrations reported here largely support the hypothesis that plants with the highest mescaline concentrations - particularly E. pachanoi from Peru - are most associated with documented shamanic use.

Analytical characterization of three trifluoromethyl‐substituted methcathinone isomers

Cathinone derivatives display a wide range of pharmacological activities and uses; some of them are used as prescription medicines, while others are encountered within a recreational context and are available without a prescription over the Internet and in retail shops around the world. One of the difficulties involved in the unambiguous identification of these new psychoactive substances is the lack of suitable reference standards, particularly when dealing with unreported derivatives and positional isomers. In order to address this need, three trifluoromethyl analogues of the psychostimulant methcathinone, with a CF(3) substituent at the 2-, 3- and 4-position of the phenyl ring (2-TFMAP 1, 3-TFMAP 2 and 4-TFMAP 3), have been prepared for analytical characterization using ATR-FTIR, (1)H and (13) C NMR, and GC-(EI/CI)-ion trap-MS. Differentiation among isomers was feasible by IR, for example when assessing the carbonyl stretch at 1711 (1), 1693 (2) and 1688 (3) cm(-1) , respectively. In addition to the expected iminium base peak at m/z 58, EI-MS displayed key ions at m/z 173, 145, 125, 95, and 75. Separation of isomers was possible under GC conditions. A characteristic feature under CI conditions was the loss of water from the [M + H](+) yielding m/z 214 in addition to m/z 58. Studies currently underway show that the three CF(3) -methcathinone analogues have central nervous system effects and that the 4-CF(3) isomer 3 is more potent as a serotonin uptake inhibitor and releasing agent than the 3-CF(3) and 2-CF(3) counterparts.

Receptor binding profiles and quantitative structure–affinity relationships of some 5-substituted-N,N-diallyltryptamines

N,N-Diallyltryptamine (DALT) and 5-methoxy-N,N-diallyltryptamine (5-MeO-DALT) are two tryptamines synthesized and tested by Alexander Shulgin. In self-experiments, 5-MeO-DALT was reported to be psychoactive in the 12-20mg range, while the unsubstituted compound DALT had few discernible effects in the 42-80 mg range. Recently, 5-MeO-DALT has been used in nonmedical settings for its psychoactive effects, but these effects have been poorly characterized and little is known of its pharmacological properties. We extended the work of Shulgin by synthesizing additional 5-substituted-DALTs. We then compared them to DALT and 5-MeO-DALT for their binding affinities at 45 cloned receptors and transporter proteins. Based on in vitro binding affinity, we identified 27 potential receptor targets for the 5-substituted-DALT compounds. Five of the DALT compounds had affinity in the 10-80 nM range for serotonin 5-HT1A and 5-HT2B receptors, while the affinity of DALT itself at 5-HT1A receptors was slightly lower at 100 nM. Among the 5-HT2 subtypes, the weakest affinity was at 5-HT2A receptors, spanning 250-730 nM. Five of the DALT compounds had affinity in the 50-400 nM range for serotonin 5-HT1D, 5-HT6, and 5-HT7 receptors; again, it was the unsubstituted DALT that had the weakest affinity at all three subtypes. The test drugs had even weaker affinity for 5-HT1B, 5-HT1E, and 5-HT5A subtypes and little or no affinity for the 5-HT3 subtype. These compounds also had generally nanomolar affinities for adrenergic α2A, α2B, and α2C receptors, sigma receptors σ1 and σ2, histamine H1 receptors, and norepinephrine and serotonin uptake transporters. They also bound to other targets in the nanomolar-to-low micromolar range. Based on these binding results, it is likely that multiple serotonin receptors, as well as several nonserotonergic sites are important for the psychoactive effects of DALT drugs. To learn whether any quantitative structure-affinity relationships existed, we evaluated correlations among physicochemical properties of the congeneric 5-substituted-DALT compounds. The descriptors included electronic (σp), hydrophobic (π), and steric (CMR) parameters. The binding affinity at 5-HT1A, 5-HT1D, 5-HT7, and κ opioid receptors was positively correlated with the steric volume parameter CMR. At α2A, α2B, and α2C receptors, and at the histamine H1 receptor, binding affinity was correlated with the Hammett substituent parameter σp; higher affinity was associated with larger σp values. At the σ2 receptor, higher affinity was correlated with increasing π. These correlations should aid in the development of more potent and selective drugs within this family of compounds.

Synthesis and characterization of 5-methoxy-2- methyl-N,N-dialkylated tryptamines

The absence of reference material is a commonly experienced difficulty among medical and forensic professionals tasked with identifying new psychoactive substances that are encountered for the first time. The identification of newly emerging substances lies at the heart of forensic and clinical analysis, and a proactive public health policy calls for a thorough analysis of the properties of new psychoactive substances before they appear in the emergency clinic, where they may be noticed because of adverse reactions or toxicity. For example, a wide range of N,N-dialkyltryptamines show psychoactive properties in humans and these tryptamines are sometimes encountered as intoxicants. However, most of the existing reference data on new psychoactive tryptamines have been obtained retrospectively, after reports of acute toxicities. To address the need for reference standards for new tryptamines, thirteen 5-methoxy-2-methyl-N,N-dialkyltryptamines were prepared. Analytical characterization was based on ¹H and ¹³C nuclear magnetic resonance (NMR), gas chromatography-electron ionization ion-trap mass spectrometry (GC-EI-IT-MS) and chemical ionization-ion-trap tandem mass spectrometry (CI-IT-MS/MS), respectively. Differentiation among isomers was feasible by NMR and MS. In addition to the expected iminium ion base peak, indole-related key ions were detected under EI-IT-MS conditions at m/z 174, 159, 131, 130, and 103. CI-IT-MS/MS analysis of the 5-methoxy-2-methyl derivatives revealed the presence of m/z 188 in addition to [M+H]+ and the iminium species. This study served as an extension from previous work on isomeric 5-ethoxylated counterparts and confirmed the ability to differentiate between the two groups. The data provided here add to the existing body of literature and aim to serve both forensic and clinical communities.

Receptor binding profiles and behavioral pharmacology of ring-substituted N,N-diallyltryptamine analogs

&NA; Substantial effort has been devoted toward understanding the psychopharmacological effects of tryptamine hallucinogens, which are thought to be mediated by activation of 5‐HT2A and 5‐HT1A receptors. Recently, several psychoactive tryptamines based on the N,N‐diallyltryptamine (DALT) scaffold have been encountered as recreational drugs. Despite the apparent widespread use of DALT derivatives in humans, little is known about their pharmacological properties. We compared the binding affinities of DALT and its 2‐phenyl‐, 4‐acetoxy‐, 4‐hydroxy‐, 5‐methoxy‐, 5‐methoxy‐2‐methyl‐, 5‐fluoro‐, 5‐fluoro‐2‐methyl‐, 5‐bromo‐, and 7‐ethyl‐derivatives at 45 receptor and transporter binding sites. Additionally, studies in C57BL/6 J mice examined whether these substances induce the head twitch response (HTR), a 5‐HT2A receptor‐mediated response that is widely used as a behavioral proxy for hallucinogen effects in humans. Most of the test drugs bound to serotonin receptors, &sgr; sites, &agr;2‐adrenoceptors, dopaminergic D3 receptors, histaminergic H1 receptors, and the serotonin transporter. DALT and several of the ring‐substituted derivatives were active in the HTR assay with the following rank order of potency: 4‐acetoxy‐DALT > 5‐fluoro‐DALT > 5‐methoxy‐DALT > 4‐hydroxy‐DALT > DALT > 5‐bromo‐DALT. 2‐Phenyl‐DALT, 5‐methoxy‐2‐methyl‐DALT, 5‐fluoro‐2‐methyl‐DALT, and 7‐ethyl‐DALT did not induce the HTR. HTR potency was not correlated with either 5‐HT1A or 5‐HT2A receptor binding affinity, but a multiple regression analysis indicated that 5‐HT2A and 5‐HT1A receptors make positive and negative contributions, respectively, to HTR potency (R2 = 0.8729). In addition to supporting the established role of 5‐HT2A receptors in the HTR, these findings are consistent with evidence that 5‐HT1A activation by tryptamine hallucinogens buffers their effects on HTR. This article is part of the Special Issue entitled ‘Psychedelics: New Doors, Altered Perceptions’. HighlightsA new class of recreational drugs are derived from N,N‐Diallyltryptamine (DALT).DALT derivatives are relatively nonselective for serotonin receptors.DALT derivatives induce the head twitch response (a 5‐HT2A‐mediated behavior) in mice.Both 5‐HT2A and 5‐HT1A receptors contribute to head twitch potency.