Persistent binding at dopamine transporters determines sustained psychostimulant effects.

Psychostimulants interacting with the dopamine transporter (DAT) can be used illicitly or for the treatment of specific neuropsychiatric disorders. However, they can also produce severe and persistent adverse events. Often, their pharmacological properties in vitro do not fully correlate to their pharmacological profile in vivo. Here, we investigated the pharmacological effects of enantiomers of pyrovalerone, α-pyrrolidinovalerophenone, and 3,4-methylenedioxypyrovalerone as compared to the traditional psychostimulants cocaine and methylphenidate, using a variety of in vitro, computational, and in vivo approaches. We found that in vitro drug-binding kinetics at DAT correlate with the time-course of in vivo psychostimulant action in mice. In particular, a slow dissociation (i.e., slow koff) of S-enantiomers of pyrovalerone analogs from DAT predicts their more persistent in vivo effects when compared to cocaine and methylphenidate. Overall, our findings highlight the critical importance of drug-binding kinetics at DAT for determining the in vivo profile of effects produced by psychostimulant drugs.

Exploring a Lux® i-Amylose-3 column in normal phase and polar-organic mode for chiral separation of cathinone derivatives and pyrovalerones using high-performance liquid chromatography.

Each year, new psychoactive substances appear on the global drug market leading to constant changes. Most of these compounds with stimulating effect possess a chiral center, thus leading to two enantiomers with presumably different pharmacological properties. Among them, synthetic cathinones, often misleadingly traded as "bath salts," play an important role. There is little knowledge about the distinct effect of the enantiomers. The aim of this study was to test a commercially available Lux® i-Amylose-3 column by HPLC-UV for enantiorecognition of cathinone derivatives. Overall, 80 compounds were tested in normal phase mode, where 75 substances were separated under initial conditions. After method optimization, at least partial separation was achieved for the remaining compounds. The same set of substances was measured in polar-organic mode, where 63 analytes were resolved into their enantiomers under initial conditions with very short retention times. Both modes showed complementary results for the individual compounds. Furthermore, the tested methods proved to be suitable for differentiation of positional isomers, which can be useful for drug checking programs. All measurements were carried out under isocratic conditions, and intraday and interday repeatability tests were performed.

Synthesis and absolute configuration of cyclic synthetic cathinones derived from α-tetralone.

The emergence of new synthetic cathinones continues to be a matter of public health concern. In fact, already known products (drugs) are being rapidly replaced by new structurally related alternatives, whereby modifications in the basic cathinone structure are used by manufacturers to circumvent the legislation. On the other hand, some derivatives of synthetic cathinones represent important pharmaceuticals with antidepressant properties. In the search for pharmaceutically relevant analogs, the main goal of the present study was to design and characterize novel cyclic α-tetralone-based derivatives of synthetic cathinones. We synthesized a series of derivatives and verified their chemical structure. Subsequently, chiral separation has been accomplished by high-performance liquid chromatography (HPLC) equipped with a circular dichroism (CD) detector, which directly provided CD spectra of the enantiomers of the analyzed substances at 252 nm. Using density functional theory calculations, we have obtained stable conformers of selected enantiomers in solution and their relative abundances, which we used to simulate their spectra. The experimental and calculated data have been used to assign the absolute configuration of six as-yet unknown synthetic cathinones.

Metaphedrone (3-Methylmethcathinone): Pharmacological, Clinical, and Toxicological Profile.

Introduction: Synthetic cathinones are a group of novel psychoactive substances used as an alternative to classical recreational drugs. As a result of legal prohibitions on older generations of these compounds, new formulations appeared on the drug market. One of them is metaphedrone (3-methylmethcathinone, 3-MMC), a structural isomer of 4-methylmethcathinone and a psychostimulant drug. Metaphedrone became popular in a large number of countries in a short period of time. The aim: The collection, analysis, and review of relevant research on the subject of metaphedrone in order to present information about the pharmacological, clinical, and toxicological profile of this compound. An assessment of the significance and role of metaphedrone in consumption patterns of novel psychoactive substances among recreational drug users. Methodology: By using search engines like Google Scholar and PubMed, the relevant literature on metaphedrone was looked for and analyzed. The search was not limited to a specific period of time. All information regarding the compound of interest was analyzed and presented. Key results and discussion: All novel psychoactive substances are abused due to their pronounced stimulatory, hallucinogenic, dissociative, and euphoric and/or relaxing characteristics. Users of 3-methylmethcathinone usually opt for this substance for recreational purposes and/or sexual stimulation. Metaphedrone has the potential to cause a psychological dependence to the users. It was determined in relevant studies that most users are from 17 to 50 years of age. Older users usually administer metaphedrone intravenously, while younger ones usually choose snorting and oral ingestion of the drug. In Serbia, metaphedrone is a legally controlled substance. The pharmacodynamic properties make metaphedrone similar to classical recreational drugs. The method of administration, mainly repeated administration in a single session, could be explained using the pharmacokinetic profile of the drug. The most reported symptoms of intoxication were those of a sympathomimetic nature, such as tachycardia, chest pain, hypertension, diaphoresis, and agitation. Most intoxications and fatal outcomes occurred to users who combined several psychoactive substances. The correlation between measured blood concentrations of the drug and outcomes of intoxication was not found. The mechanisms of metaphedrone's toxicity are not fully understood. Conclusions: There is an increasing trend of abuse of metaphedrone among recreational drugs users. Future studies should focus on pharmacological and toxicological effects of metaphedrone on animals and humans.

Synthesis of emerging cathinones and validation of a SPE GC-MS method for their simultaneous quantification in blood.

Over the past 15 years, synthetic cathinones have emerged as an important class of new psychoactive substances (NPS) worldwide. The proliferation of these psychostimulants and their sought-after effects among recreational drug users pose a serious threat to public health and enormous challenges to forensic laboratories. For forensic institutions, it is essential to be one step ahead of covert laboratories, foreseeing the structural changes possible to introduce in the core skeleton of cathinones while maintaining their stimulating activity. In this manner, it is feasible to equip themselves with standards of possible new cathinones and validated analytical methods for their qualitative and quantitative detection. Therefore, the aim of the work herein described was to synthesize emerging cathinones based on the evolving patterns in the illicit drug market, and to develop an analytical method for their accurate determination in forensic situations. Five so far unreported cathinones [4'-methyl-N-dimethylbuphedrone (4-MDMB), 4'-methyl-N-ethylbuphedrone (4-MNEB), 4'-methyl-N-dimethylpentedrone (4-MDMP), 4'-methyl-N-dimethylhexedrone (4-MDMH), and 4'-methyl-N-diethylbuphedrone (4-MDEB)] and a sixth one, 4'-methyl-N-ethylpentedrone, already reported to EMCDDA and also known as 4-MEAP, were synthesized and fully characterized by nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS). An analytical method for the simultaneous quantification of these cathinones in blood, using solid phase extraction (SPE) combined with gas chromatography-mass spectrometry (GC-MS) was developed and validated. The results prove that this methodology is selective, linear, precise, and accurate. For all target cathinones, the extraction efficiency was higher than 73%, linearity was observed in the range of 10 (lower limit of quantification, LLOQ) to 800 ng/mL, with coefficients of determination higher than 0.99, and the limits of detection (LODs) were 5 ng/mL for all target cathinones. The stability of these cathinones in blood matrices is dependent on the storage conditions; 4-MNEB is the most stable compound and 4-MDMH is the least stable compound. The low limits obtained allow the detection of the compounds in situations where they are involved, even if present at low concentrations.

In vitro metabolism of cathinone positional isomers: does sex matter?

Synthetic cathinones, one of the most prevalent categories of new psychoactive substances, have been posing a serious threat to public health. Methylmethcathinones (MMCs), notably 3-MMC, have seen an alarming increase in their use in the last decade. The metabolism and toxicology of a large majority of synthetic cathinones, including 3-MMC and 2-MMC, remain unknown. Traditionally, male-derived liver materials have been used as in vitro metabolic incubations to investigate the metabolism of xenobiotics, including MMCs. Therefore, little is known about the metabolism in female-derived in vitro models and the potential sex-specific differences in biotransformation. In this study, the metabolism of 2-MMC, 3-MMC, and 4-MMC was investigated using female rat and human liver microsomal incubations, as well as male rat and human liver microsomal incubations. A total of 25 phase I metabolites of MMCs were detected and tentatively identified using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Seven sex-specific metabolites were detected exclusively using pooled male rat liver microsomal incubations. In addition, the metabolites generated from the sex-dependent in vitro metabolic incubations that were present in both male and female rat liver microsomal incubations showed differences in relative abundance. Yet, neither sex-specific metabolites nor significant differences in relative abundance were observed from pooled human liver microsomal incubations. This is the first study to report the phase I metabolic pathways of MMCs using in vitro metabolic incubations for both male and female liver microsomes, and the relative abundance of the metabolites observed from each sex.

A narrative review of the neuropharmacology of synthetic cathinones-Popular alternatives to classical drugs of abuse.

OBJECTIVE: To review the literature on the neuropharmacology of synthetic cathinones. METHODS: A comprehensive literature search was carried out across multiple databases (mainly PubMed, World Wide Web, and Google Scholar) using relevant keywords. RESULTS: Cathinones exhibit a broad toxicological profile, mimicking the effects of a wide variety of 'classic drugs' such as 3,4-methylenedioxymethamphetamine (MDMA), methamphetamine and cocaine. Even small structural changes affect their interactions with key proteins. This article reviews existing knowledge of the mechanisms of action of cathinones at the molecular level, and key findings from research on their structure-activity relationship. The cathinones are also classified according to their chemical structure and neuropharmacological profiles. CONCLUSIONS: Synthetic cathinones represent one of the most numerous and widespread groups among new psychoactive substances. Initially developed for therapeutic purposes, they quickly started to be used recreationally. With a rapidly increasing number of new agents entering the market, structure-activity relationship studies are valuable for assessing and predicting the addictive potential and toxicity of new and potential future substances. The neuropharmacological properties of synthetic cathinones are still not fully understood. A full elucidation of the role of some key proteins, including organic cation transporters, requires detailed studies.

Relationship between GABA-Ergic System and the Expression of Mephedrone-Induced Reward in Rats-Behavioral, Chromatographic and In Vivo Imaging Study.

Mephedrone is a psychoactive drug that increases dopamine, serotonin and noradrenaline levels in the central nervous system via interaction with transporters or monoamines. The aim of the presented study was to assess the role of the GABA-ergic system in the expression of mephedrone-induced reward. For this purpose, we conducted (a) a behavioral evaluation of the impact of baclofen (a GABAB receptors agonist) and GS39783 (a positive allosteric modulator of GABAB receptors) on the expression of mephedrone-induced conditioned place preference (CPP) in rats, (b) an ex vivo chromatographic determination of the GABA level in the hippocampi of rats subchronically treated with mephedrone and (c) an in vivo evaluation of GABA hippocampal concentration in rats subchronically administered with mephedrone using magnetic resonance spectroscopy (MRS). The results show that GS39783 (but not baclofen) blocked the expression of CPP induced by (20 mg/kg of) mephedrone. The behavioral effect was consistent with chromatographic analysis, which showed that mephedrone (5 and 20 mg/kg) led to a decrease in GABA hippocampal concentration. Altogether, the presented study provides a new insight into the involvement of the GABA-ergic system in the rewarding effects of mephedrone, implying that those effects are at least partially mediated through GABAB receptors, which suggests their potential role as new targets for the pharmacological management of mephedrone use disorder.

First-Generation Synthetic Cathinones Produce Arrhythmia in Zebrafish Eleutheroembryos: A New Approach Methodology for New Psychoactive Substances Cardiotoxicity Evaluation.

The increasing number of new psychoactive substances (NPS) entering the illicit drug market, especially synthetic cathinones, as well as the risk of cardiovascular complications, is intensifying the need to quickly assess their cardiotoxic potential. The present study aims to evaluate the cardiovascular toxicity and lethality induced by first-generation synthetic cathinones (mephedrone, methylone, and MDPV) and more classical psychostimulants (cocaine and MDMA) in zebrafish embryos using a new approach methodology (NAM). Zebrafish embryos at 4 dpf were exposed to the test drugs for 24 h to identify drug lethality. Drug-induced effects on ventricular and atrial heart rate after 2 h exposure were evaluated, and video recordings were properly analyzed. All illicit drugs displayed similar 24 h LC50 values. Our results indicate that all drugs are able to induce bradycardia, arrhythmia, and atrial-ventricular block (AV block), signs of QT interval prolongation. However, only MDPV induced a different rhythmicity change depending on the chamber and was the most potent bradycardia and AV block-inducing drug compared to the other tested compounds. In summary, our results strongly suggest that the NAM presented in this study can be used for screening NPS for their cardiotoxic effect and especially for their ability to prolong the QT intervals.

Synthetic Cathinones and Neurotoxicity Risks: A Systematic Review.

According to the EU Early Warning System (EWS), synthetic cathinones (SCs) are the second largest new psychoactive substances (NPS) class, with 162 synthetic cathinones monitored by the EU EWS. They have a similar structure to cathinone, principally found in Catha Edulis; they have a phenethylamine related structure but also exhibit amphetamine-like stimulant effects. Illegal laboratories regularly develop new substances and place them on the market. For this reason, during the last decade this class of substances has presented a great challenge for public health and forensic toxicologists. Acting on different systems and with various mechanisms of action, the spectrum of side effects caused by the intake of these drugs of abuse is very broad. To date, most studies have focused on the substances' cardiac effects, and very few on their associated neurotoxicity. Specifically, synthetic cathinones appear to be involved in different neurological events, including increased alertness, mild agitation, severe psychosis, hyperthermia and death. A systematic literature search in PubMed and Scopus databases according to PRISMA guidelines was performed. A total of 515 studies published from 2005 to 2022 (350 articles from PubMed and 165 from Scopus) were initially screened for eligibility. The papers excluded, according to the criteria described in the Method Section (n = 401) and after full text analyses (n = 82), were 483 in total. The remaining 76 were included in the present review, as they met fully the inclusion criteria. The present work provides a comprehensive review on neurotoxic mechanisms of synthetic cathinones highlighting intoxication cases and fatalities in humans, as well as the toxic effects on animals (in particular rats, mice and zebrafish larvae). The reviewed studies showed brain-related adverse effects, including encephalopathy, coma and convulsions, and sympathomimetic and hallucinogenic toxidromes, together with the risk of developing excited/agitated delirium syndrome and serotonin syndrome.

Genotoxicity Evaluation of The Novel Psychoactive Substance MTTA.

MTTA, also known as mephtetramine, is a stimulant novel psychoactive substance characterized by a simil-cathinonic structure. To date, little has been studied on its pharmaco-toxicological profile, and its genotoxic potential has never been assessed. In order to fill this gap, the aim of the present work was to evaluate its genotoxicity on TK6 cells in terms of its ability to induce structural and numerical chromosomal aberrations by means of a cytofluorimetric protocol of the "In Vitro Mammalian Cell Micronucleus (MN) test". To consider the in vitro effects of both the parental compound and the related metabolites, TK6 cells were treated with MTTA in the absence or presence of an exogenous metabolic activation system (S9 mix) for a short-term time (3 h) followed by a recovery period (23 h). No statistically significant increase in the MNi frequency was detected. Specifically, in the presence of S9 mix, only a slight increasing trend was observable at all tested concentrations, whereas, without S9 mix, at 75 µM, almost a doubling of the negative control was reached. For the purposes of comprehensive evaluation, a long-term treatment (26 h) was also included. In this case, a statistically significant enhancement in the MNi frequency was observed at 50 µM.

GC-MS/MS Determination of Synthetic Cathinones: 4-chloromethcathinone, N-ethyl Pentedrone, and N-ethyl Hexedrone in Oral Fluid and Sweat of Consumers under Controlled Administration: Pilot Study.

This study presents a validated GC-MS/MS method for the detection and quantification of 4-chloromethcathinone or clephedrone (4-CMC), N-ethyl Pentedrone (NEP), and N-ethyl Hexedrone (NEH, also named HEXEN) in oral fluid and sweat and verifies its feasibility in determining human oral fluid concentrations and pharmacokinetics following the administration of 100 mg of 4-CMC orally and 30 mg of NEP and NEH intranasally. A total of 48 oral fluid and 12 sweat samples were collected from six consumers. After the addition of 5 µL of methylone-d3 and 200 µL of 0.5 M ammonium hydrogen carbonate, an L/L extraction was carried out using ethyl acetate. The samples, dried under a nitrogen flow, were then derivatized with pentafluoropropionic anhydride and dried again. One microliter of the sample reconstituted in 50 µL of ethyl acetate was injected into GC-MS/MS. The method was fully validated according to international guidelines. Our results showed how, in oral fluid, the two cathinones taken intranasally were absorbed very rapidly, within the first hour, when compared with the 4-CMC which reached its maximum concentration peak in the first three hours. We observed that these cathinones were excreted in sweat in an amount equivalent to approximately 0.3% of the administered dose for 4-CMC and NEP. The total NEH excreted in sweat 4 h after administration was approximately 0.2% of the administered dose. Our results provide, for the first time, preliminary information about the disposition of these synthetic cathinones in the consumers' oral fluid and sweat after controlled administration.

Molecular Docking Assessment of Cathinones as 5-HT2AR Ligands: Developing of Predictive Structure-Based Bioactive Conformations and Three-Dimensional Structure-Activity Relationships Models for Future Recognition of Abuse Drugs.

Commercially available cathinones are drugs of long-term abuse drugs whose pharmacology is fairly well understood. While their psychedelic effects are associated with 5-HT2AR, the enclosed study summarizes efforts to shed light on the pharmacodynamic profiles, not yet known at the receptor level, using molecular docking and three-dimensional quantitative structure-activity relationship (3-D QSAR) studies. The bioactive conformations of cathinones were modeled by AutoDock Vina and were used to build structure-based (SB) 3-D QSAR models using the Open3DQSAR engine. Graphical inspection of the results led to the depiction of a 3-D structure analysis-activity relationship (SAR) scheme that could be used as a guideline for molecular determinants by which any untested cathinone molecule can be predicted as a potential 5-HT2AR binder prior to experimental evaluation. The obtained models, which showed a good agreement with the chemical properties of co-crystallized 5-HT2AR ligands, proved to be valuable for future virtual screening campaigns to recognize unused cathinones and similar compounds, such as 5-HT2AR ligands, minimizing both time and financial resources for the characterization of their psychedelic effects.

Semi-Preparative Separation, Absolute Configuration, Stereochemical Stability and Effects on Human Neuronal Cells of MDPV Enantiomers.

Synthetic cathinones, such as 3,4-methylenedioxypyrovalerone (MDPV), are widely abused due to their psychostimulant effects. As they are chiral molecules, studies of their stereochemical stability (racemization can occur in certain temperatures and acidic/basic environments) and of their biological and/or toxicity effects (enantiomers might display different properties) are of great relevance. In this study, the liquid chromatography (LC) semi-preparative enantioresolution of MDPV was optimized to collect both enantiomers with high recovery rates and enantiomeric ratio (e.r.) values. The absolute configuration of the MDPV enantiomers was determined by electronic circular dichroism (ECD) with the aid of theoretical calculations. The first eluted enantiomer was identified as S-(-)-MDPV and the second eluted enantiomer was identified as R-(+)-MDPV. A racemization study was performed by LC-UV, showing enantiomers' stability up to 48 h at room temperature and 24 h at 37 °C. Racemization was only affected by higher temperatures. The potential enantioselectivity of MDPV in cytotoxicity and in the expression of neuroplasticity-involved proteins-brain-derived neurotrophic factor (BDNF) and cyclin-dependent kinase 5 (Cdk5)-was also evaluated using SH-SY5Y neuroblastoma cells. No enantioselectivity was observed.

Amphetamine-type Stimulants: Novel Insights into their Actions and use Patterns.

This review focuses on the effects and mechanisms of action of amphetamine-type stimulants (ATS) and their adverse effects on the cardiovascular, nervous, and immune systems. ATS include amphetamine (AMPH), methamphetamine (METH, "crystalmeth," or "ice"), methylenedioxymethamphetamine (MDMA, "ecstasy," or "Molly"), MDMA derivatives (e.g., methylenedioxyamphetamine [MDA] and methylenedioxy-N-ethylamphetamine [MDEA]), khat, and synthetic cathinones. The first section of this paper presents an overview of the historical aspects of ATS use, their initial clinical use, and regulations. The second part reviews the acute and chronic impact and the most salient clinical effects of ATS on the central nervous and cardiovascular systems, skin, and mouth. The chemical structure, pharmacokinetics, and classic and non-canonical pharmacological actions are covered in the third section, briefly explaining the mechanisms involved. In addition, the interactions of ATS with the central and peripheral immune systems are reviewed. The last section presents data about the syndemic of ATS and opioid use in the North American region, focusing on the increasing adulteration of METH with fentanyl.

Behavioural and neurochemical effects after repeated administration of N-ethylpentylone (ephylone) in mice.

N-ethyl-pentylone (NEP), also known as 'ephylone' and N-ethylnorpentylone, has been identified as one of the most recent novel psychostimulants to emerge into the illicit drug market and it has been associated with some intoxications and even fatalities. However, little is known about the consequences of its repeated consumption as well as the role of the monoaminergic system in such consequences. Thus, the aim of our study was to investigate the neurochemical profile and the behavioural effects after both acute and repeated NEP exposure. Male OF1 mice were acutely (1, 3, 10 mg/kg, i.p.) or repeatedly (1, 3, 10 mg/kg, i.p., 5 days, twice/day) exposed to NEP, and anxiety-like behaviour, aggressiveness, social interaction, depressive-like symptoms, body temperature, changes in monoaminergic enzymes and neurotransmitters levels as well as ΔFosB in striatum and prefrontal cortex (PFC) from post-mortem tissue were analysed short after drug-exposure or during drug-withdrawal. Acute administration of NEP induced anxiolytic effects but also an aggressive behaviour and social exploration deficits in mice, which persist during NEP-withdrawal. Moreover, NEP induced hyperthermia as well as depressive-like symptoms after repeated administrations that may be related to the decrease in serotonin and noradrenaline levels observed in striatum and PFC. Finally, the long-term increase in ΔFosB levels in striatum after NEP chronic exposure points to a high risk of dependence. Altogether indicates that NEP consumption induces different neurological and neuropsychiatric disorders accompanied by changes in the monoaminergic system, posing a threat to public health.

A unique case of death by MDPHP with no other co-ingestion: a forensic toxicology case.

Synthetic cathinones are a class of psychoactive drugs that have become, in recent years, of quite common observation in medical and toxicological forensic field. MDPHP (3,4-methylenedioxy-α-pyrrolidinohexanophenone) belongs to this class of substances but lethal acute intoxication caused by this specific substance without other co-ingestions has never been described in literature. We are presenting the unique case of a fatal acute intoxication caused by MDPHP in a 48-year-old man carried to the A&E department of a big Milanese hospital where he suddenly deceased after brief time. Clinical records, autopsy examination, histological findings, and toxicological analysis, assessed via a Q-Exactive Orbitrap with a HPLC system and LC/MS-MS system, are discussed. This case report may represent the first case of this type of intoxication and might help in improving recognition and treatment of these particular cases.

Interactions between impulsivity and MDPV self-administration in rats.

Synthetic cathinones, such as 3,4-methylenedioxypyrovalerone (MDPV), are recreational drugs of abuse often identified in 'bath salts' preparations. Humans report compulsive patterns of bath salts use, and previous work suggests that a subset of rats develop unusually high levels of MDPV self-administration. This study aims to test the hypothesis that high levels of impulsivity (e.g., inability to withhold responding for a sucrose reward) will predispose rats to high levels of MDPV self-administration relative to rats with lower levels of impulsivity. The 1-choice serial reaction time task (1-CSRTT) was used to assess impulsivity (i.e., premature responding) in 10 female and 10 male Sprague Dawley rats. Rats were then allowed to self-administer 0.032 mg/kg/inf MDPV or 0.32 mg/kg/inf cocaine, after which full dose-response curves for MDPV (0.001-0.1 mg/kg/inf) or cocaine (0.01-1 mg/kg/inf) were generated under a FR5 schedule of reinforcement. After a history of self-administering MDPV or cocaine, impulsivity was reassessed under the 1-CSRTT, prior to evaluating the acute effects of MDPV (0.032-0.32 mg/kg) or cocaine (0.1-1 mg/kg) on impulsivity. Level of impulsivity was not correlated with subsequent levels of either MDPV or cocaine self-administration, and level of drug self-administration was also not correlated with subsequent levels of impulsivity, although acute administration of MDPV and cocaine did increase premature responding. In failing to find direct relationships between either impulsivity and subsequent drug-taking behaviour, or drug-taking behaviour and subsequent assessments of impulsivity, these findings highlight the complexity inherent in the associations between impulsive behaviour and drug-taking behaviour in both animal models and humans.

Determination of total cathinones with a single molecularly imprinted fluorescent sensor assisted by electromembrane microextraction.

An electromembrane microextraction (EME)-assisted fluorescent molecularly imprinted polymer (MIP) sensing method is presented for detecting the total cathinone drugs in urine samples. In this detection system, the clean-up ability of EME eliminated the matrix effects on both target binding with MIPs and the luminescence of the fluorophore in the sensor. Moreover, by optimizing the extraction conditions of EME, different cathinone drugs with a same concentration show a same response on the single aggregation induced emission (AIE) based MIP (AIE-MIP) sensor (λex = 360 nm, λem = 467 nm). The recoveries were 57.9% for cathinone (CAT) and 78.2% for methcathinone (MCAT). The EME-assisted "light-up" AIE-MIP sensing method displayed excellent performance with a linear range of 2.0-12.0 µmol L-1 and a linear determination coefficient (R2) of 0.99. The limit of detection (LOD) value for EME-assisted "light-up" AIE-MIP sensing method was 0.3 µmol L-1. The relative standard deviation (RSD) values for the detection were found to be within the range 2.0-12.0%. To the best of our knowledge, this is the first time that determination of total illicit drugs with a single fluorescent MIP sensor was achieved and also the first utilization of sample preparation to tune the sensing signal of the sensor to be reported. We believe that this versatile combination of fluorescent MIP sensor and sample preparation can be used as a common protocol for sensing the total amount of a group of analytes in various fields.

Neuropsychopharmacology of Emerging Drugs of Abuse: meta- and para-Halogen-Ring-Substituted α-PVP ("flakka") Derivatives.

Changes in the molecular structure of synthetic cathinones has led to an increase in the number of novel emerging drugs in the illicit drug market at an unprecedented rate. Unfortunately, little is known about the neuropsychopharmacology of recently emerged halogen-substituted α-PVP derivatives. Thus, the aim of this study was to investigate the role of para- and meta-halogen (F-, Cl-, and Br-) substitutions on the in vitro, in silico, and in vivo effects of α-pyrrolidinopentiophenone (α-PVP) derivatives. HEK293 cells expressing the human dopamine or serotonin transporter (hDAT and hSERT) were used for the uptake inhibition and transporter affinity assays. Molecular docking was used to model the interaction mechanism against DAT. Swiss CD-1 mice were used for the horizontal locomotor activity, open field test, and conditioned place preference paradigm. All compounds demonstrated potent DA uptake inhibition and higher DAT selectivity than cocaine. Meta-substituted cathinones showed higher DAT/SERT ratios than their para- analogs, which correlates with an increased psychostimulant effect in vivo and with different meta- and para-in silico interactions at DAT. Moreover, all compounds induced rewarding and acute anxiogenic effects in mice. In conclusion, the present study demonstrates the role of meta- and para-halogen substitutions in the mechanism of action and provides the first evidence of the rewarding and anxiety-like properties of halogenated α-PVP derivatives.