Pharmacology of MDMA- and Amphetamine-Like New Psychoactive Substances

Alpha-methyltryptamine and 5-(2-methylaminopropyl)-benzofuran (5-MAPB) fatal co-intoxication: case report and review of literature

The scientific literature contains little reliable data regarding new psychoactive substances and designer drugs, making it difficult to assess toxic blood levels and potentially lethal threshold. Here, we report a fatal co-intoxication involving two uncommon drugs ‒ alpha-methyltryptamine (AMT) and 5-(2-methylaminopropyl)-benzofuran (5-MAPB) ‒ combined with exposure to benzodiazepines, ephedrine, and norephedrine. AMT and 5-MAPB were quantified using ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC/MS-MS), revealing concentrations of AMT 4690 ng/mL and 5-MAPB 101 ng/mL in postmortem peripheral blood. We additionally reviewed the literature to help interpret the likely roles of these molecules in the occurrence of death.

Arginine vasopressin deficiency: diagnosis, management and the relevance of oxytocin deficiency

Polyuria-polydipsia syndrome can be caused by central diabetes insipidus, nephrogenic diabetes insipidus or primary polydipsia. To avoid confusion with diabetes mellitus, the name 'central diabetes insipidus' was changed in 2022 to arginine vasopressin (AVP) deficiency and 'nephrogenic diabetes insipidus' was renamed as AVP resistance. To differentiate the three entities, various osmotic and non-osmotic copeptin-based stimulation tests have been introduced in the past decade. The hypertonic saline test plus plasma copeptin measurement emerged as the test with highest diagnostic accuracy, replacing the water deprivation test as the gold standard in differential diagnosis of the polyuria-polydipsia syndrome. The mainstay of treatment for AVP deficiency is AVP replacement with desmopressin, a synthetic analogue of AVP specific for AVP receptor 2 (AVPR2), which usually leads to rapid improvements in polyuria and polydipsia. The main adverse effect of desmopressin is dilutional hyponatraemia, which can be reduced by regularly performing the so-called desmopressin escape method. Evidence from the past few years suggests an additional oxytocin deficiency in patients with AVP deficiency. This potential deficiency should be further evaluated in future studies, including feasible provocation tests for clinical practice and interventional trials with oxytocin substitution.

Augmentation of intracranial self-stimulation induced by amphetamine-like drugs in Period circadian regulator 2 knockout mice is associated with intracellular Ca2+ levels

Over the past decade, new psychoactive substances (NPS) have emerged in the illegal drug market and have continued to attract attention from the international community. Among these, amphetamine-like NPS, classified as stimulants, constitute a significant proportion. However, the pharmacological characteristics and mechanisms underlying addiction to amphetamine-like NPS remain poorly understood. Given that circadian rhythms are linked to the brain stimulation effects of methamphetamine (METH) and amphetamine, we investigated the effects of METH, 1-(4-methoxyphenyl)-N-methylpropan-2-amine (PMMA), and 1-(benzofuran-5-yl)-N-ethylpropan-2-amine (5-EAPB) on intracranial self-stimulation (ICSS) in wild-type (WT) or Period circadian regulator 2 knockout mice. Amphetamine-like drugs increase intracellular Ca2+ levels to provoke dopamine release, so we examined the impact of Per2 knockdown on intracellular Ca2+ levels in PC12 cells to elucidate a potential mechanism underlying NPS-induced ICSS enhancement. Our ICSS results showed that METH and PMMA significantly increased brain stimulation in Per2 knockout mice compared to WT mice. Similarly, METH and PMMA induced higher Ca2+ fluorescence intensity in Per2 knockdown PC12 cells than in control cells. In contrast, 5-EAPB did not produce significant changes in either ICSS or Ca2+ signaling. These findings suggest that Per2 plays a crucial role in the brain stimulation effects of amphetamine-like drugs through the regulation of intracellular Ca2+.

Characterization of the Neurochemical and Behavioral Effects of the Phenethylamine 2-Cl-4,5-MDMA in Adolescent and Adult Male Rats

BACKGROUND

The proliferation of novel psychoactive substances (NPS) in the drug market raises concerns about uncertainty on their pharmacological profile and the health hazard linked to their use. Within the category of synthetic stimulant NPS, the phenethylamine 2-Cl-4,5-methylenedioxymethamphetamine (2-Cl-4,5-MDMA) has been linked to severe intoxication requiring hospitalization. Thereby, the characterization of its pharmacological profile is urgently warranted.

METHODS

By in vivo brain microdialysis in adolescent and adult male rats we investigated the effects of 2-Cl-4,5-MDMA on dopamine (DA) and serotonin (5-HT) neurotransmission in two brain areas critical for the motivational and rewarding properties of drugs, the nucleus accumbens (NAc) shell and the medial prefrontal cortex (mPFC). Moreover, we evaluated the locomotor and stereotyped activity induced by 2-Cl-4,5-MDMA and the emission of 50-kHz ultrasonic vocalizations (USVs) to characterize its affective properties.

RESULTS

2-Cl-4,5-MDMA increased dialysate DA and 5-HT in a dose-, brain area-, and age-dependent manner. Notably, 2-Cl-4,5-MDMA more markedly increased dialysate DA in the NAc shell and mPFC of adult than adolescent rats, while the opposite was observed on dialysate 5-HT in the NAc shell, with adolescent rats being more responsive. Furthermore, 2-Cl-4,5-MDMA stimulated locomotion and stereotyped activity in both adolescent and adult rats, although to a greater extent in adolescents. Finally, 2-Cl-4,5-MDMA did not stimulate the emission of 50-kHz USVs.

CONCLUSIONS

This is the first pharmacological characterization of 2-Cl-4,5-MDMA demonstrating that its neurochemical and behavioral effects may differ between adolescence and adulthood. These preclinical data could help understanding the central effects of 2-Cl-4,5-MDMA by increasing awareness on possible health damage in users.

Characterization of neurotransmitter inhibition for seven cathinones by a proprietary fluorescent dye method

Many new psychoactive substances (NPS) are stimulants, and information about their potency and abuse potential is often lacking. To start addressing this need, a method measuring the inhibition of the dopamine, serotonin, and norepinephrine transporters (DAT, SERT, and NET) by stimulant drugs was developed. The use of a proprietary fluorescent dye mixture and three cell lines (CHO-K1, HEK 293, and MDCK), each expressing a single transporter, allowed for a semiautomated, one-pot determination of inhibition in a 384-well format. The method was validated using well characterized stimulants, including cocaine, amphetamine, 3,4-methylenedioxymethamphetamine (MDMA), α-PVP, and fluoxetine and performed similarly to other methods. Seven synthetic cathinones all showed highest potency for DAT inhibition, followed by NET and SERT. The rank potency for DAT inhibition IC50 (nM) was MPHP (4.53) > 4Cl-α-PVP (8.05) > 3F-α-PVP (12.7) > α-PiHP (13.4) > N-ethylpentylone (16.9) > N-ethylhexedrone (44.5) > 4-methylpentedrone (261). All but 4-methylpentedrone were more potent than amphetamine (257) and cocaine (111). The DAT/SERT inhibition ratio for the cathinones was in the range from 5.02 for 4-methylpentedrone to >3730 for α-PiHP, compared to 1.64 for cocaine and >4030 for α-PVP. All seven substances had inhibition profiles similar to those of potent stimulants with high abuse potential.

5-HT_FAsTR: a versatile, label-free, high-throughput, fluorescence-based microplate assay to quantify serotonin transport and release

The neurotransmitter serotonin plays a pivotal role in mood and depression. It also acts as a vasoconstrictor within blood vessels and is the main neurotransmitter in the gastrointestinal system. In neurotransmission, released serotonin is taken up by serotonin transporters, which are principal targets of antidepressants and the psychostimulant, ecstasy. The investigation of serotonin transporters have relied almost exclusively on the use of radiolabeled serotonin in heterogenous end-point assays. Here we adapt the genetically encoded fluorescent biosensor, iSeroSnFR, to establish and validate the Serotonin (5-HT) Fluorescence Assay for Transport and Release (5-HT_FAsTR) for functional and pharmacological studies of serotonin transport and release. We demonstrate the applicability of the method for the study of a neuronal, high-affinity, low-capacity serotonin transporter (SERT) as well as an extraneuronal low-affinity, high-capacity organic cation transporter and mutants thereof. 5HT_FAsTR offers an accessible, versatile and reliable semi-homogenous assay format that only relies on a fluorescence plate reader for repeated, real-time measurements of serotonin influx and efflux. 5HT_FAsTR accelerates and democratizes functional characterization and pharmacological studies of serotonin transporters and genetic variants thereof in disease states such as depression, anxiety and ADHD.

Subjective long-term emotional and social effects of recreational MDMA use: the role of setting and intentions

MDMA is a recreational drug commonly used to enhance euphoria, but it is also used in non-party settings with self-insight or social connection intentions. Yet, little is known about whether distinct consumer groups are formed based on consumption setting and intention. We aimed to characterize different types of recreational MDMA users based on consumption setting and intentions, and to examine their differences in perceptions of long-term social-emotional effects of MDMA use. We analyzed self-reports of 766 individuals (ages 18-61, mostly from Western countries), reporting on their MDMA consumption habits and perceived effects. We used a K-medoids clustering algorithm to identify distinct types of consumption settings and intentions. We identified three setting types - party settings with friends (N = 388), private home settings (N = 132), mixed settings (N = 246) - and three intention types - euphoria and energy (N = 302), self-insight (N = 219), mixed intentions (N = 245). Members of the self-insight and mixed intentions clusters reported considerably more long-term socio-emotional benefits than members of the euphoria and energy cluster. No differences were observed between the setting clusters. In this particular sample, more long-term benefits than harms were reported. Our findings suggest that the long-term social-emotional benefits of MDMA are associated with whether users seek self-insight or have mixed intentions.

MDMA-Based Psychotherapy in Treatment-Resistant Post-Traumatic Stress Disorder (PTSD): A Brief Narrative Overview of Current Evidence

Post-traumatic stress disorder (PTSD) is a debilitating mental health disorder that causes significant dysfunction in individuals. Currently, there are many approved pharmacotherapy and psychotherapy treatment options for PTSD, but unfortunately, half of the patients do not respond to traditional therapies. In this article, we review clinical trials and research on 3,4-methylenedioxymethamphetamine (MDMA)-assisted psychotherapy in PTSD patients, its pharmacokinetics, and current treatment guidelines for PTSD. Our findings are based on the results of the efficacy of MDMA-assisted psychotherapy from six phase II randomized controlled trials. MDMA-assisted psychotherapy for PTSD has received the "breakthrough therapy" designation from the FDA. MDMA can reduce PTSD symptoms even in treatment-resistant cases by increasing certain neurohormones, i.e., dopamine, serotonin, norepinephrine, and oxytocin. It also modulates activities in the brain regions involved in fear and anxiety. Future research is needed to show whether the advantages outweigh the disadvantages and whether its use can be integrated into available treatment options for PTSD.

Drug-induced social connection: both MDMA and methamphetamine increase feelings of connectedness during controlled dyadic conversations

MDMA is a stimulant-like drug with distinctive empathogenic effects. Its pro-social effects, such as feelings of connectedness, may contribute to both its popularity as a recreational drug and its apparent value as an adjunct to psychotherapy. However, little is known about the behavioral processes by which MDMA affects social interactions. This investigation examined the effects of MDMA (100 mg versus placebo; N = 18) on feelings of connectedness with an unfamiliar partner during a semi-structured casual conversation. A separate study examined the effects of a prototypic stimulant methamphetamine (MA; 20 mg versus placebo; N = 19) to determine the pharmacological specificity of effects. Oxytocin levels were obtained in both studies. Compared to placebo, both MDMA and MA increased feelings of connection with the conversation partners. Both MDMA and MA increased oxytocin levels, but oxytocin levels were correlated with feeling closer to the partner only after MDMA. These findings demonstrate an important new dimension of the pro-social effects of MDMA, its ability to increase feelings of connectedness during casual conversations between two individuals. Surprisingly, MA had a similar effect. The findings extend our knowledge of the social effects of these drugs, and illustrate a sensitive method for assessing pro-social effects during in-person dyadic encounters.

Nanowired Delivery of Mesenchymal Stem Cells with Antioxidant Compound H-290/51 Reduces Exacerbation of Methamphetamine Neurotoxicity in Hot Environment

Military personnel are often exposed to hot environments either for combat operations or peacekeeping missions. Hot environment is a severe stressful situation leading to profound hyperthermia, fatigue and neurological impairments. To avoid stressful environment, some people frequently use methamphetamine (METH) or other psychostimulants to feel comfortable under adverse situations. Our studies show that heat stress alone induces breakdown of the blood-brain barrier (BBB) and edema formation associated with reduced cerebral blood flow (CBF). On the other hand, METH alone induces hyperthermia and neurotoxicity. These effects of METH are exacerbated at high ambient temperatures as seen with greater breakdown of the BBB and brain pathology. Thus, a combination of METH use at hot environment may further enhance the brain damage-associated behavioral dysfunctions. METH is well known to induce severe oxidative stress leading to brain pathology. In this investigation, METH intoxication at hot environment was examined on brain pathology and to explore suitable strategies to induce neuroprotection. Accordingly, TiO₂-nanowired delivery of H-290/51 (150 mg/kg, i.p.), a potent chain-breaking antioxidant in combination with mesenchymal stem cells (MSCs), is investigated in attenuating METH-induced brain damage at hot environment in model experiments. Our results show that nanodelivery of H-290/51 with MSCs significantly enhanced CBF and reduced BBB breakdown, edema formation and brain pathology following METH exposure at hot environment. These observations are the first to point out that METH exacerbated brain pathology at hot environment probably due to enhanced oxidative stress, and MSCs attenuate these adverse effects, not reported earlier.

Amphetamine, methamphetamine, and MDMA in hair samples from a rehabilitation facility: Validation and applicability of HF-LPME-GC-MS

INTRODUCTION

It is known that drug abuse jeopardizes economic and social development. Toxicological analyses can guide prevention and treatment strategies in rehabilitation facilities. The current greatest challenge is finding easily adaptable and less costly sensitive methods that meet the principles of green chemistry. Hair, as a biological matrix, has several advantages, and its ability to detect consumption for longer periods keeping the matrix stable and unaltered stands out. This manuscript addresses the use of a miniaturized technique in an alternative matrix, by making use of a reduced amount of solvents to quantify amphetamines, aiming to guide prevention and treatment strategies in rehabilitation facilities.

METHODS

A Hollow Fiber Liquid-phase Microextraction (HF-LPME) technique for extracting amphetamines from hair samples with Gas Chromatography-Mass Spectrometry (CG-MS) was validated, adapted, and applied to ten samples from patients of a rehabilitation facility.

RESULTS

The technique proved to be sensitive, accurate, precise, and not affected by interference from the biological matrix and the linear range for the analytes was 0.2 to 20 ng mg ^-1. The three analytes were quantified in the samples analyzed. It is worth stressing that the patients were young.

CONCLUSION

The HF-LPME-GC-MS technique complied with the principles of green chemistry, and proved to be a sensitive technique, adaptable to the routine of common laboratories. Validation in the analysis phase with authentic samples, thus, showed that it can be an important tool for preventing and controlling drug addiction.

Effects of the Phenethylamine 2-Cl-4,5-MDMA and the Synthetic Cathinone 3,4-MDPHP in Adolescent Rats: Focus on Sex Differences

The illicit drug market of novel psychoactive substances (NPSs) is expanding, becoming an alarming threat due to increasing intoxication cases and insufficient (if any) knowledge of their effects. Phenethylamine 2-chloro-4,5-methylenedioxymethamphetamine (2-Cl-4,5-MDMA) and synthetic cathinone 3,4-methylenedioxy-α-pyrrolidinohexanophenone (3,4-MDPHP) are new, emerging NPSs suggested to be particularly dangerous. This study verified whether these two new drugs (i) possess abuse liability, (ii) alter plasma corticosterone levels, and (iii) interfere with dopaminergic transmission; male and female adolescent rats were included to evaluate potential sex differences in the drug-induced effects. Findings show that the two NPSs are not able to sustain reliable self-administration behavior in rats, with cumulatively earned injections of drugs being not significantly different from cumulatively earned injections of saline in control groups. Yet, at the end of the self-administration training, females (but not males) exhibited higher plasma corticosterone levels after chronic exposure to low levels of 3,4-MDPHP (but not of 2-Cl-4,5-MDMA). Finally, electrophysiological patch-clamp recordings in the rostral ventral tegmental area (rVTA) showed that both drugs are able to increase the firing rate of rVTA dopaminergic neurons in males but not in females, confirming the sex dimorphic effects of these two NPSs. Altogether, this study demonstrates that 3,4-MDPHP and 2-Cl-4,5-MDMA are unlikely to induce dependence in occasional users but can induce other effects at both central and peripheral levels that may significantly differ between males and females.

Psychedelics in the treatment of unipolar and bipolar depression

This is a narrative review about the role of classic and two atypical psychedelics in the treatment of unipolar and bipolar depression. Since the 1990s, psychedelics experience a renaissance in biomedical research. The so-called classic psychedelics include lysergic acid diethylamide (LSD), psilocybin, mescaline and ayahuasca. Characteristic effects like alterations in sensory perception, as well as emotion- and self-processing are induced by stimulation of serotonin 2A receptors in cortical areas. The new paradigm of psychedelic-assisted psychotherapy suggests a therapeutic framework in which a safely conducted psychedelic experience is integrated into a continuous psychotherapeutic process. First randomized, controlled trials with psilocybin show promising efficacy, tolerability, and adherence in the treatment of unipolar depression. On the other hand, classic psychedelics seem to be associated with the induction of mania, which is an important issue to consider for the design of research and clinical protocols. So called atypical psychedelics are a heterogeneous group with overlapping subjective effects but different neurobiological mechanisms. Two examples of therapeutic value in psychiatry are 3,4-methyl​enedioxy​methamphetamine (MDMA) and ketamine. Since 2020 the ketamine enantiomer esketamine has been granted international approval for treatment-resistant unipolar depression, and also first evidence exists for the therapeutic efficacy of ketamine in bipolar depression. Whether psychedelics will fulfil current expectations and find their way into broader clinical use will depend on future rigorous clinical trials with larger sample sizes. A well-considered therapeutic and legal framework will be crucial for these substances to create new treatment settings and a potential paradigm shift.

Human behavioral pharmacology of stimulant drugs: An update and narrative review

Stimulant use disorders present an enduring public health concern. Chronic stimulant use is associated with a range of health problems, with notable increases in stimulant overdose that disproportionately affect marginalized populations. With these persistent problems, it is important to understand the behavioral and pharmacological factors that contribute to stimulant use in humans. The purpose of this chapter is to provide an update and narrative review on recent human laboratory research that has evaluated the behavioral pharmacology of stimulant drugs. We focus on two prototypic stimulants: cocaine as a prototype monoamine reuptake inhibitor and d-amphetamine as a prototype monoamine releaser. As such, placebo controlled human laboratory studies that involved administration of doses of cocaine or d-amphetamine and were published in peer reviewed journals within the last 10 years (i.e., since 2011) are reviewed. Primary outcomes from these studies are subjective effects, reinforcing effects, cognitive/behavioral effects, and discriminative stimulus effects. Both cocaine and d-amphetamine produce classical stimulant-like behavioral effects (e.g., increase positive subjective effects, function as reinforcers), but there are notable gaps in the literature including understanding sex differences in response to stimulant drugs, cognitive-behavioral effects of stimulants, and influence of use history (e.g., relatively drug naïve vs drug experienced) on stimulant effects.

Preventive Medication Patterns in Bipolar Disorder and Their Relationship With Comorbid Substance Use Disorders in a Cross-National Observational Study

OBJECTIVE

The potential role of sub-optimal pharmacological treatment in the poorer outcomes observed in bipolar disorder (BD) with vs. without comorbid substance use disorders (SUDs) is not known. Thus, we investigated whether patients with BD and comorbid SUD had different medication regimens than those with BD alone, in samples from France and Norway, focusing on compliance to international guidelines.

METHODS

Seven hundred and seventy patients from France and Norway with reliably ascertained BD I or II (68% BD-I) were included. Medication information was obtained from patients and hospital records, and preventive treatment was categorized according to compliance to guidelines. We used Bayesian and regression analyses to investigate associations between SUD comorbidity and medication. In the Norwegian subsample, we also investigated association with lack of medication.

RESULTS

Comorbid SUDs were as follows: current tobacco smoking, 26%, alcohol use disorder (AUD), 16%; cannabis use disorder (CUD), 10%; other SUDs, 5%. Compliance to guidelines for preventive medication was lacking in 8%, partial in 44%, and complete in 48% of the sample. Compliance to guidelines was not different in BD with and without SUD comorbidity, as was supported by Bayesian analyses (highest Bayes Factor = 0.16). Cross national differences in treatment regimens led us to conduct country-specific adjusted regression analyses, showing that (1) CUD was associated with increased antipsychotics use in France (OR = 2.4, 95% CI = 1.4-3.9, p = 0.001), (2) current tobacco smoking was associated with increased anti-epileptics use in Norway (OR = 4.4, 95% CI = 1.9-11, p < 0.001), and (3) AUD was associated with decreased likelihood of being medicated in Norway (OR = 1.2, 95% CI = 1.04-1.3, p = 0.038).

CONCLUSION

SUD comorbidity in BD was overall not associated with different pharmacological treatment in our sample, and not related to the level of compliance to guidelines. We found country-specific associations between comorbid SUDs and specific medications that warrant further studies.

Molecular mechanisms of action of stimulant novel psychoactive substances that target the high-affinity transporter for dopamine

Drug misuse is a significant social and public health problem worldwide. Misused substances exert their neurobehavioural effects through changing neural signalling within the brain, many of them leading to substance dependence and addiction in the longer term. Among drugs with addictive liability, there are illicit classical stimulants such as cocaine and amphetamine, and their more recently available counterparts known as novel psychoactive substances (NPS). Stimulants normally increase dopamine availability in the brain, including the pathway implicated in reward-related behaviour. This pattern is observed in both animal and human brain. The main biological target of stimulants, both classical and NPS, is the dopamine transporter (DAT) implicated in the dopamine-enhancing effects of these drugs. This article aims at reviewing research on the molecular mechanisms underpinning the interactions between stimulant NPS, such as benzofurans, cathinones or piperidine derivatives and DAT, to achieve a greater understanding of the core phenomena that decide about the addictive potential of stimulant NPS. As the methodology is essential in the process of experimental research in this area, we review the applications of in vitro, in vivo and in silico approaches. The latter, including molecular dynamics, attracts the focus of the present review as the method of choice in molecular and atomistic investigations of the mechanisms of addiction of stimulant NPS. Research of this kind is of interest to not only scientists but also health professionals as updated knowledge of NPS, their modes of action and health risks, is needed to tackle the challenges posed by NPS misuse.

Anxiety-related Symptoms following the Sporadic Use of Ecstasy - A Case Study

3,4-methylenedioxymethamphetamine (MDMA/"ecstasy") is widespread in the electronic club scene, but MDMA has also been suggested for the treatment of anxiety spectrum disorders like posttraumatic stress disorder (PTSD) and social anxiety in autistic adults. Here, we report a case of a high functioning 24-old student with a sporadic recreational use of ecstasy, and a history of a single episode of obsessive-compulsive disorder (OCD). A few days after using ecstasy during a period of stressful life events, he developed a complex depersonalization/derealization syndrome (DDS) including intermittent distortions of time and very short intermittent episodes of misidentification of persons. Furthermore, obsessive thoughts reappeared and he suffered a panic attack for the first time in his life. Under combined pharmacological treatment and psychotherapy, symptoms gradually subsided until full remission after 14 months. Some months after discontinuation of escitalopram, however, panic attacks recurred, evolving into a regular pattern. Even if MDMA is a promising tool for the treatment of some anxiety spectrum disorders in the framework of substance-assisted psychotherapy, the use of ecstasy might be also harmful for some patients with a history of anxiety or dissociative symptoms, when used recreationally or as a self-medication outside of a controlled clinical setting.

Psychedelics as Reemerging Treatments for Anxiety Disorders: Possibilities and Challenges in a Nascent Field

Although psychedelics initially showed promise in treating anxiety disorders, psychedelics were criminalized and research halted in the early 1970s. A subsequent resurgence of research into psychiatric benefits of psychedelic-assisted psychotherapy in the last 20 years has led to a potential paradigm shift in the treatment of numerous psychiatric disorders, including anxiety disorders. Despite accumulating evidence and likely U.S. Food and Drug Administration approval in the next 2-3 years, the emerging field of psychedelic medicine faces several challenges. Obstacles include ongoing barriers on the regulatory level, lack of education, stigma among mental health clinicians, cost and scalability, and a dearth of specialized personnel prepared to provide these treatments. Deeper issues of ethical responsibility and inclusivity also exist given the historical discovery and use of psychedelics by indigenous peoples throughout the world as well the ongoing disparities in mental health delivery and access within psychiatry and psychedelic research.

Beyond ecstasy: Alternative entactogens to 3,4-methylenedioxymethamphetamine with potential applications in psychotherapy

The last two decades have seen a revival of interest in the entactogen 3,4-methylenedioxy-N-methylamphetamine (MDMA) as an adjunct to psychotherapy, particularly for the treatment of post-traumatic stress disorder. While clinical results are highly promising, and MDMA is expected to be approved as a treatment in the near future, it is currently the only compound in its class of action that is being actively investigated as a medicine. This lack of alternatives to MDMA may prove detrimental to patients who do not respond well to the particular mechanism of action of MDMA or whose treatment calls for a modification of MDMA's effects. For instance, patients with existing cardiovascular conditions or with a prolonged history of stimulant drug use may not fit into the current model of MDMA-assisted psychotherapy, and could benefit from alternative drugs. This review examines the existing literature on a host of entactogenic drugs, which may prove to be useful alternatives in the future, paying particularly close attention to any neurotoxic risks, neuropharmacological mechanism of action and entactogenic commonalities with MDMA. The substances examined derive from the 1,3-benzodioxole, cathinone, benzofuran, aminoindane, indole and amphetamine classes. Several compounds from these classes are identified as potential alternatives to MDMA.

The SLC6A3 gene polymorphism is related to the development of attentional functions but not to ADHD

Neuropharmacological and human clinical studies have suggested that the brain dopaminergic system is substantively involved in normal and pathological phenotypes of attention. Dopamine transporter gene (SLC6A3) was proposed as a candidate gene for Attention-Deficit/Hyperactivity Disorder (ADHD). We investigated the effect of the SLC6A3 variants on cognitive performance in ADHD and healthy children and teenagers. Participants completed cognitive tasks measuring attentional switching, selective and sustained attention, and effectiveness of alerting, orienting and executive attention. We estimated the effects of 40 bp variable number of tandem repeat (VNTR) polymorphism located in the 3' untranslated region (3' UTR) (9-repeat vs 10-repeat allele) of the SLC6A3 gene, ADHD diagnosis, age, and their interactions as predictors of cognitive performance. ADHD children demonstrated deficits in most of the examined attention processes, persistent within the examined age range (9-16 years). No significant effects were observed for the interaction of ADHD and the SLC6A3 polymorphism, but the results revealed a significant main effect of SLC6A3 genotype in the entire research sample. Subjects carrying 9R allele performed the switching task significantly worse in comparison to children with 10R/10R or 10R/11R genotype. SLC6A3 polymorphism moderated age-related improvements in orienting and attentional switching. Results suggest that SLC6A3 genotype influence these attentional/cognitive functions which deficits are not the key symptoms in ADHD.

Pharmacotherapy of anxiety disorders in the 21st century: A call for novel approaches

While limited advances have occurred in the past 30 years in the pharmacological management of anxiety and stress-related disorders, novel molecular pathways both within and without the monoamine systems are currently under investigation and offer promising new avenues for more effective future treatments. Enhancing psychotherapy approaches with pharmacological compounds offers the potential to not only transform the standard of care of these conditions, but more broadly would introduce a paradigm shift in the way medications and their role in psychiatric care are conceptualised. Although further human trials and more translational research are sorely needed, continuing to pursue innovative mechanisms and treatments is hoped to yield substantial results in the coming decades and a departure from the reliance on chemical agents of the 20th century.

Novel pharmacological targets in drug development for the treatment of anxiety and anxiety-related disorders

Current medication for anxiety disorders is suboptimal in terms of efficiency and tolerability, highlighting the need for improved drug treatments. In this review an overview of drugs being studied in different phases of clinical trials for their potential in the treatment of fear-, anxiety- and trauma-related disorders is presented. One strategy followed in drug development is refining and improving compounds interacting with existing anxiolytic drug targets, such as serotonergic and prototypical GABAergic benzodiazepines. A more innovative approach involves the search for compounds with novel mechanisms of anxiolytic action using the growing knowledge base concerning the relevant neurocircuitries and neurobiological mechanisms underlying pathological fear and anxiety. The target systems evaluated in clinical trials include glutamate, endocannabinoid and neuropeptide systems, as well as ion channels and targets derived from phytochemicals. Examples of promising novel candidates currently in clinical development for generalised anxiety disorder, social anxiety disorder, panic disorder, obsessive compulsive disorder or post-traumatic stress disorder include ketamine, riluzole, xenon with one common pharmacological action of modulation of glutamatergic neurotransmission, as well as the neurosteroid aloradine. Finally, compounds such as D-cycloserine, MDMA, L-DOPA and cannabinoids have shown efficacy in enhancing fear-extinction learning in humans. They are thus investigated in clinical trials as an augmentative strategy for speeding up and enhancing the long-term effectiveness of exposure-based psychotherapy, which could render chronic anxiolytic drug treatment dispensable for many patients. These efforts are indicative of a rekindled interest and renewed optimism in the anxiety drug discovery field, after decades of relative stagnation.

The SERT Met172 Mouse: An Engineered Model To Elucidate the Contributions of Serotonin Signaling to Cocaine Action

Cocaine abuse and addiction remain highly prevalent and, unfortunately, poorly treated. It is well-known that essential aspects of cocaine's addictive actions involve the drug's ability to block the presynaptic dopamine (DA) transporter (DAT), thereby elevating extracellular levels of DA in brain circuits that subserve reward, reinforcement, and habit. Less well appreciated are the multiple DA-independent actions of cocaine, activities that we and others believe contribute key pieces to the puzzle of cocaine addiction, treatment, and relapse. In particular, a significant body of work points to altered serotonin (5-HT) signaling as one such component, not surprising given that, relative to DAT, cocaine acts as potently to block the 5-HT transporter (SERT) as to block DAT, and thereby elevates extracellular 5-HT levels throughout the brain when reward-eliciting DA elevations occur. To elucidate the contribution of SERT antagonism to the actions of cocaine, we engineered a mouse model that significantly reduces cocaine potency at SERT without disrupting the expression or function of SERT in vivo. In this short Perspective, we review the rationale for development of the SERT Met172 model, the studies that document the pharmacological impact of the Ile172Met substitution in vitro and in vivo, and our findings with the model that demonstrate serotonergic contributions to the genetic, physiological, and behavioral actions of cocaine.

Structure-activity relationships of bath salt components: substituted cathinones and benzofurans at biogenic amine transporters

RATIONALE

New psychoactive substances (NPSs), including substituted cathinones and other stimulants, are synthesized, sold on the Internet, and ingested without knowledge of their pharmacological activity and/or toxicity. In vitro pharmacology plays a role in therapeutic drug development, drug-protein in silico interaction modeling, and drug scheduling.

OBJECTIVES

The goal of this research was to determine mechanisms of action that may indicate NPS abuse liability.

METHODS

Affinities to displace the radioligand [¹²⁵I]RTI-55 and potencies to inhibit [³H]neurotransmitter uptake for 22 cathinones, 6 benzofurans and another stimulant were characterized using human embryonic kidney cells stably expressing recombinant human transporters for dopamine, norepinephrine, or serotonin (hDAT, hNET, or hSERT, respectively). Selected compounds were tested for potencies and efficacies at inducing [³H]neurotransmitter release via the transporters. Computational modeling was conducted to explain plausible molecular interactions established by NPS and transporters.

RESULTS

Most α-pyrrolidinophenones had high hDAT potencies and selectivities in uptake assays, with hDAT/hSERT uptake selectivity ratios of 83-360. Other substituted cathinones varied in their potencies and selectivities, with N-ethyl-hexedrone and N-ethyl-pentylone having highest hDAT potencies and N-propyl-pentedrone having highest hDAT selectivity. 4-Cl-ethcathinone and 3,4-methylenedioxy-N-propylcathinone had higher hSERT selectivity. Benzofurans generally had low hDAT selectivity, especially 1-(2,3-dihydrobenzofuran-5-yl)-N-methylpropan-2-amine, with 25-fold higher hSERT potency. Consistent with this selectivity, the benzofurans were releasers at hSERT. Modeling indicated key amino acids in the transporters' binding pockets that influence drug affinities.

CONCLUSIONS

The α-pyrrolidinophenones, with high hDAT selectivity, have high abuse potential. Lower hDAT selectivity among benzofurans suggests similarity to methylenedioxymethamphetamine, entactogens with lower stimulant activity.

No Influence of Dopamine System Gene Variations on Acute Effects of MDMA

3,4-Methylenedioxymethamphetamine (MDMA, ecstasy) is a recreational substance also investigated as medication for posttraumatic stress disorder. Dopamine (DA) system stimulation likely contributes to the acute mood effects of amphetamines, including MDMA. Genetic variants, such as single-nucleotide polymorphisms (SNPs), and polymorphic regions of the DA system genes may in part explain interindividual differences in the acute responses to MDMA in humans. We characterized the effects of common genetic variants within genes coding for key players in the DA system including the dopamine D2 receptor (DRD2/ANKK1 rs1800497, DRD2 rs6277, and rs107959), the dopamine transporter (DAT1 rs28363170, rs3836790, rs6347, rs11133767, rs11564774, rs460000, and rs463379), and dopamine D4 receptor [DRD4, variable-number tandem repeat (VNTR)] on the subjective and autonomic response to MDMA (125 mg) in pooled data from randomized, placebo-controlled, crossover studies in a total of 149 healthy subjects. Plasma concentrations of MDMA were used as covariate in the analysis to control for individual pharmacokinetic (metabolic and weight) differences. None of the tested genetic polymorphisms within the DA system altered effects of MDMA when adjusting for multiple comparisons. Genetic variations in genes coding for players of the DA system are unlikely to explain interindividual variations in the acute effects of MDMA in humans.

Modulation of Social Cognition via Hallucinogens and "Entactogens"

Social cognition is a fundamental ability in human everyday lives. Deficits in social functioning also represent a core aspect of many psychiatric disorders. Yet, despite its significance, deficits in social cognition skills are insufficiently targeted by current treatments. Hallucinogens and entactogens have been shown to have the potential to modulate social processing. This article reviews the literature on the influence of hallucinogens and entactogens on social processing in controlled experimental studies in humans and elucidates the underlying neurobiological and neuropharmacological mechanisms. Furthermore, it identifies current knowledge gaps and derives implications for hallucinogen-assisted treatment approaches as well as the development of novel medication for trans-diagnostic impairments in social cognition.

Dopaminergic neurotoxic effects of 3-TFMPP derivatives

Designer drugs are synthetically formulated to mimic the psychostimulatory effects of an original controlled/illegal drug of abuse. Designer drugs have similar chemical structure or functional analog as compared to existing controlled psychostimulatory drugs. There is a substantial rise in the production and use of designer drugs globally. Piperazine designer drugs were synthesized as an alternative to MDMA and have shown to induce numerous toxic effects leading to huge health, safety, law enforcement & monetary problems, and lethality. Currently, there are very few studies on the dopaminergic neurotoxicity of 1-(3-trifluoromethylphenyl) piperazine (3-TFMPP) and its derivatives (structural congeners). N27 rat dopaminergic neurons are valid cells to investigate the neurotoxic effects and establish the neurotoxic mechanisms of various substances. In the current study, we studied the time and dose-dependent neurotoxicity mechanisms of dopaminergic neurotoxicity of 3-TFMPP (parent compound) and its derivatives (2-TFMPP, 4-TFMPP). TFMPP derivatives-induced significant neurotoxicity (induced dopaminergic neuronal death. TFMPP derivatives-induced oxidative stress, mitochondrial dysfunction, apoptosis and decreased tyrosine hydroxylase expression. If the use of designer drugs are not strictly regulated and restricted around the world, this can lead to numerous central and peripheral disorders leading to a liability to the current and future society.