Current Neuropharmacology - Volume 15, Issue 5, 2017

Background: New psychoactive substances are conquering the drug scene. Among these substances, cathinone derivatives have been observed since late in the years 2000. At that time, there was evidence of increasing use of the synthetic cathinone mephedrone, particularly amongst clubbers. Although the emergent drugs have an aura of safety, there is an increasing amount of experiences on their secondary effects. Mephedrone is known to induce psychosis. Method: Given the potential negative effects of mephedrone, the laboratory was asked to test for the drug in hair, a cumulative matrix that can document single, occasional or repetitive abuse of xenobiotics. Mephedrone was tested in hair by GC/MS, using a standard procedure developed for stimulants such as amphetamine or ecstasy. Results: In the head hair of 24 positive abusers, mephedrone was identified in the range 0.1 to 87 ng/mg, clearly determining 2 populations, one with co-administration of ecstasy and a second without ecstasy. In the first population, mephedrone concentrations were 0.1 to 5 ng/mg; in the second population, mephedrone concentrations were 3 to 87 ng/mg. These findings should help in the understanding the addiction of subjects. In 4 separate forensic cases, mephedrone was identified in hair of abusers, including a rape case (0.54 ng/mg), a fatal car crash (0.38 ng/mg), a fatal drowning (1.21 ng/mg), and a fatal overdose (6.99 ng/mg). Conclusion: Hair testing for new psychoactive substances appears as a good complement to standard urine analyses. This study confirms the increasing diffusion of new drugs among the forensic population of abusers.

Background: New Psychoactive Substances (NPS) belong to several chemical classes, including phenethylamines, piperazines, synthetic cathinones and synthetic cannabinoids. Development and validation of analytical methods for the determination of NPS both in traditional and alternative matrices is of crucial importance to study drug metabolism and to associate consumption to clinical outcomes and eventual intoxication symptoms. Among different biological matrices, hair is the one with the widest time window to investigate drug-related history and demonstrate past intake. Method: The aim of this paper was to overview the trends of the rapidly evolving analytical methods for the determination of NPS in hair and the usefulness of these methods when applied to real cases. A number of rapid and sensitive methods for the determination of NPS in hair matrix has been recently published, most of them using liquid chromatography coupled to mass spectrometry. Hair digestion and subsequent solid phase extraction or liquid-liquid extraction were described as well as extraction in organic solvents. For most of the methods limits of quantification at picogram per milligram hair were obtained. Results: The measured concentrations for most of the NPS in real samples were in the range of picograms of drug per milligram of hair. Interpretation of the results and lack of cut-off values for the discrimination between chronic consumption and occasional use or external contamination are still challenging. Conclusions: Methods for the determination of NPS in hair are continually emerging to include as many NPS as possible due to the great demand for their detection.

Background: Metabolite profiling of novel psychoactive substances (NPS) is critical for documenting drug consumption. N-(1-amino-3,3-dimethyl-1-oxobutan-2-yl)-1-(4-fluorobenzyl)-1Hindazole- 3-carboxamide (ADB-FUBINACA) is an emerging synthetic cannabinoid whose toxicological and metabolic data are currently unavailable. Methods: We aimed to determine optimal markers for identifying ADB-FUBINACA intake. Metabolic stability was evaluated with human liver microsome incubations. Metabolites were identified after 1 and 3 h incubation with pooled human hepatocytes, liquid chromatography- high resolution mass spectrometry in positive-ion mode (5600+ TripleTOF®, Sciex) and several data mining approaches (MetabolitePilot™, Sciex). Results: Metabolite separation was achieved on an Ultra Biphenyl column (Restek®); full-scan TOFMS and information-dependent acquisition MS/MS data were acquired. ADB-FUBINACA microsomal half-life was 39.7 min, with a predicted hepatic clearance of 9.0 mL/min/kg and a 0.5 extraction ratio (intermediate-clearance drug). Twenty-three metabolites were identified. Major metabolic pathways were alkyl and indazole hydroxylation, terminal amide hydrolysis, subsequent glucuronide conjugations, and dehydrogenation. Conclusion: We recommend ADB-FUBINACA hydroxyalkyl, hydroxydehydroalkyl and hydroxylindazole metabolites as ADB-FUBINACA intake markers. N-dealkylated metabolites are not specific ADB-FUBINACA metabolites and should not be used as definitive markers of consumption. This is the first ADB-FUBINACA in vitro metabolism study; in vivo experiments enabling pharmacokinetic and pharmacodynamics studies or urine from authentic clinical/forensic cases are needed to confirm our results.

Background: 3-Methoxyphencyclidine (3-MeO-PCP) and 3-methoxyrolicyclidine (3-MeOPCPy) are two new psychoactive substances (NPS). The aims of the present study were the elucidation of their metabolic fate in rat and pooled human liver microsomes (pHLM), the identification of the cytochrome P450 (CYP) isoenzymes involved, and the detectability using standard urine screening approaches (SUSA) after intake of common users’ doses using gas chromatography-mass spectrometry (GC-MS), liquid chromatography-multi-stage mass spectrometry (LC-MSn), and liquid chromatography-high-resolution tandem mass spectrometry (LC-HR-MS/MS). Methods: For metabolism studies, rat urine samples were treated by solid phase extraction or simple precipitation with or without previous enzymatic conjugate cleavage. After analyses via LC-HR-MSn, the phase I and II metabolites were identified. Results: Both drugs showed multiple aliphatic hydroxylations at the cyclohexyl ring and the heterocyclic ring, single aromatic hydroxylation, carboxylation after ring opening, O-demethylation, and glucuronidation. The transferability from rat to human was investigated by pHLM incubations, where Odemethylation and hydroxylation were observed. The involvement of the individual CYP enzymes in the initial metabolic steps was investigated after single CYP incubations. For 3-MeO-PCP, CYP 2B6 was responsible for aliphatic hydroxylations and CYP 2C19 and CYP 2D6 for O-demethylation. For 3-MeO-PCPy, aliphatic hydroxylation was again catalyzed by CYP 2B6 and O-demethylation by CYP 2C9 and CYP 2D6 Conclusions: As only polymorphically expressed enzymes were involved, pharmacogenomic variations might occur, but clinical data are needed to confirm the relevance. The detectability studies showed that the authors’ SUSAs were suitable for monitoring the intake of both drugs using the identified metabolites.

Background: Synthetic cannabinoids (SCs) have become an increasing issue in forensic toxicology. Controlled human studies evaluating pharmacokinetic data of SCs are lacking and only few animal studies have been published. Thus, an interpretation of analytical results found in intoxicated or poisoned individuals is difficult. Therefore, the distribution of two selected SCs, namely 4-ethylnaphthalen-1-yl-(1-pentylindol-3-yl)methanone (JWH-210) and 2-(4-methoxyphenyl)-1-(1- pentyl-indol-3-yl)methanone (RCS-4) as well as Δ9-tetrahydrocannabinol (THC) as reference were examined in pigs. Methods: Pigs (n = 6 per drug) received a single intravenous 200 μg/kg BW dose of JWH-210, RCS- 4, or THC. Six hours after administration, the animals were exsanguinated and relevant organs, important body fluids such as bile, and tissues such as muscle and adipose tissue, as well as the bradytrophic specimens dura and vitreous humor were collected. After hydrolysis and solid phase extraction, analysis was performed by LC-MS/MS. To overcome matrix effects of the LC-MS/MS analysis, a standard addition method was applied for quantification. Results: The parent compounds could be detected in every analyzed specimen with the exception of THC that was not present in dura and vitreous humor. Moderate concentrations were present in brain, the site of biological effect. Metabolite concentrations were highest in tissues involved in metabolism and/or elimination Conclusions: Besides kidneys and lungs routinely analyzed in postmortem toxicology, brain, adipose, and muscle tissue could serve as alternative sources, particularly if other specimens are not available. Bile fluid is the most appropriate specimen for SCs and THC metabolites detection.

Background: Recently, a large amount of physical and sexual performance enhancing products have started to be freely sold mainly on internet web sites as dietary supplements. However, there a high suspicion that pharmacologically active substance, prohibited in these products, can be present to provide the expected effect. Methods: A simple and rapid systematic toxicological analysis by gas chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry has been applied after a liquidliquid extraction at acidic, neutral and alkaline pH with chloroform-isopropanol (9:1 v/v). The assays were validated in the range from 10 mg to 250 mg/g products showing a good linearity for the calibration curves (r2 ≥0.99). Mean extraction recoveries of analytes from different products were always higher than 90% and intra-assay and inter-assay precision and accuracy were always better than 15%. Results: The developed method was applied to the analysis of products with a high percentage of sales in websites and smart and sexy shops. In twelve of eighty supplements, anabolic steroids, antiestrogenic drugs, psychoactive substances and sildenafil and analogs were identified and quantified. Conclusion: Eventual health hazards caused by the hidden presence of pharmacologically active substances in physical and sexual performance enhancing products are reported.

Background: Evolutionary research on drug abuse has hitherto been restricted to proximate studies, considering aetiology, mechanism, and ontogeny. However, in order to explain the recent emergency of a new behavioral pattern (e.g. ‘the e-psychonaut style’) of novel psychoactive substances’ (NPS) intake, a complementary evolutionary model may be needed. Objective: A range of evolutionary interpretations on the ‘psychonaut style’ and the recent emergency of NPS were here considered. Method: The PubMed database was searched in order to elicit evolutionary theory-based documents commenting on NPS/NPS users/e-psychonauts. Results: The traditional ‘shamanic style’ use of entheogens/plant-derived compounds may present with a range of similarities with the ‘e-psychonauts’ use of mostly of hallucinogen/psychedelic NPS. These users consider themselves as ‘new/technological’ shamans. Conclusion: Indeed, a range of evolutionary mechanisms, such as: optimal foraging, costly signaling, and reproduction at the expense of health may all cooperate to explain the recent spread and diffusion of the NPS market, and this may represent a reason of concern.

Background: Mephedrone is a β-ketoamphetamine belonging to the family of synthetic cathinones, an emerging class of designer drugs known for their hallucinogenic and psychostimulant properties as well as for their abuse potential. Objective: The aim of this review was to examine the emerging scientific literature on the possible mephedrone-induced neurotoxicity, yet not well defined due to the limited number of experimental studies, mainly carried on animal models. Materials and Methods: Relevant scientific articles were identified from international literature databases (Medline, Scopus, etc.) using the keywords: “Mephedrone”, “4-MMC,” “neurotoxicity,” “neuropharmacology”, “patents”, “monoamine transporters” and “neurochemical effects”. Results: Of the 498 sources initially found, only 36 papers were suitable for the review. Neurotoxic effect of mephedrone on 5-hydroxytryptamine (5-HT) and dopamine (DA) systems remains controversial. Although some studies in animal models reported no damage to DA nerve endings in the striatum and no significant changes in brain monoamine levels, some others suggested a rapid reduction in 5-HT and DA transporter function. Persistent serotonergic deficits were observed after binge like treatment in a warm environment and in both serotonergic and dopaminergic nerve endings at high ambient temperature. Oxidative stress cytotoxicity and an increase in frontal cortex lipid peroxidation were also reported. In vitro cytotoxic properties were also observed, suggesting that mephedrone may act as a reductant agent and can also determine changes in mitochondrial respiration. However, due to the differences in the design of the experiments, including temperature and animal model used, the results are difficult to compare. Conclusions: Further studies on toxicology and pharmacology of mephedrone are therefore necessary to establish an appropriate treatment for substance abuse and eventual consequences for public health

Background: A new trend among users of new psychoactive substances’ the consumption of “herbal highs”: plant parts containing psychoactive substances. Most of the substances extracted from herbs, in old centuries were at the centre of religious ceremonies of ancient civilizations. Currently, these herbal products are mainly sold by internet web sites and easily obtained since some of them have no legal restriction. Objective: We reviewed psychoactive effects and neuropharmacology of the most used “herbal highs” with characterized active principles, with studies reporting mechanisms of action, pharmacological and subjective effects, eventual secondary effects including intoxications and/or fatalities Method: The PubMed database was searched using the following key.words: herbal highs, Argyreia nervosa, Ipomoea violacea and Rivea corymbosa; Catha edulis; Datura stramonium; Piper methysticum; Mitragyna speciosa. Results: Psychoactive plants here reviewed have been known and used from ancient times, even if for some of them limited information still exist regarding subjective and neuropharmacological effects and consequent eventual toxicity when plants are used alone or in combination with “classical” drugs of abuse. Conclusion: Some “herbal highs” should be classified as harmful drugs since chronic administration has been linked with addiction and cognitive impairment; for some others taking into consideration only the recent trends of abuse, studies investigating these aspects are lacking.

Background: The term “chemsex” was coined to indicate the voluntary intake of psychoactive and non psychoactive drugs in the context of recreational settings to facilitate and/or to enhance sexual intercourses mostly among men who have sex with other men (MSM). Objective: The authors aimed to review the mechanisms of action, the toxicity and the pattern of use and abuse of substances involved in “chemsex” practice together with the sociocultural background underlying it and the health-related consequences that they may have. Results: Gamma-hydroxybutyrate, gamma-butyrolactone,1,4-butanediol, mephedrone, methamphetamine, sildenafil, tadalafil, vardenafil and alkyl nitrites have been described in their role of “chemsex drugs” including pharmacological action and in their implication to impair capacities to chose sexual partners and consensual sex. Moreover, it has been demonstrated that sexual activity over protracted length of time under the influence of chemsex drugs can result in rectal trauma or penile abrasions and a significant increase of the risk of transmission of sexual transmitted diseases, especially in case of condomless intercourses, which are frequent in this context, representing therefore a serious health threat. Conclusion: One of the major problems to establish health policy priority interventions for chemsex is the lack of available epidemiological data on the issue. Finally, social actions should be taken in order to break down the barriers that currently exist among chemsex drug users in accessing services, including the shame and stigma often associated with drug use. In conclusion, more specific resources to face high risks of infections and HIV transmission are required in bisexual and homosexual individuals having SUID: sex under the influence of drugs.

Background: The G protein-coupled receptor 55 (GPR55) is a mammalian orphan receptor that awaits a formal classification. There are an increasing number of reports directed to know the physiology and pathophysiology of this receptor. Lamentably, its functions in the central nervous system (CNS) have been scarcely elucidated. Methods: A bibliographic search in PubMed database about GPR55 actions in the CNS was made. The information was grouped for brain structures to facilitate the interpretation. Finally, we constructed a schematic representation of the current knowledge about the potential participation of GPR55 in some physiological and pathophysiological events. Results: Seventy nine papers were included in the review. Only few of them showed data about GPR55 (mRNA/protein) expression in multiple brain areas. The rest showed findings in different preparations both in vitro and in vivo conditions that allowed us to speculate a potential activity of GPR55 in the different brain areas. Conclusion: GPR55 mRNA is expressed in several brain areas as the hippocampus, hypothalamus, frontal cortex and cerebellum; but due to the lack of information, only some speculative information about its function in these regions has been suggested. Therefore, this review provide relevant information to motivate further research about GPR55 physiology/pathophysiology in the CNS.

Background: Recombinant antibody fragments are promising alternatives to full-length immunoglobulins and offer important advantages compared with conventional monoclonal antibodies: extreme specificity, higher affinity, superior stability and solubility, reduced immunogenicity as well as easy and inexpensive large-scale production. Objective: In this article we will review and discuss recombinant antibodies that are being evaluated for neurodegenerative diseases in pre-clinical models and in clinical studies and will summarize new strategies that are being developed to optimize their stability, specificity and potency for advancing their use. Methods: Articles describing recombinant antibody fragments used for neurological diseases were selected (PubMed) and evaluated for their significance. Results: Different antibody formats such as single-chain fragment variable (scFv), single-domain antibody fragments (VHHs or sdAbs), bispecific antibodies (bsAbs), intrabodies and nanobodies, are currently being studied in pre-clinical models of cancer as well as infectious and autoimmune diseases and many of them are being tested as therapeutics in clinical trials. Immunotherapy approaches have shown therapeutic efficacy in several animal models of Alzheimer´s disease (AD), Parkinson disease (PD), dementia with Lewy bodies (DLB), frontotemporal dementia (FTD), Huntington disease (HD), transmissible spongiform encephalopathies (TSEs) and multiple sclerosis (MS). It has been demonstrated that recombinant antibody fragments may neutralize toxic extra- and intracellular misfolded proteins involved in the pathogenesis of AD, PD, DLB, FTD, HD or TSEs and may target toxic immune cells participating in the pathogenesis of MS. Conclusion: Recombinant antibody fragments represent a promising tool for the development of antibody-based immunotherapeutics for neurodegenerative diseases.

Background: Akathisia continues to be a significant challenge in current neurological and psychiatric practice. Prompt and accurate detection is often difficult and there is a lack of consensus concerning the neurobiological basis of akathisia. No definitive treatment has been established for akathisia despite numerous preclinical and clinical studies.] Method: We reviewed antipsychotic-induced akathisia including its clinical presentation, proposed underlying pathophysiology, current and under investigation therapeutic strategies. Conclusion: Despite the initial promise that second generation antipsychotics would be devoid of akathisia effects, this has not been confirmed. Currently, there are limited therapeutic options for the clinical practice and the evidence supporting the most widely used treatments (beta blockers, anticholinergic drugs) is still absent or inconsistent.