Methylenedioxymethamphetamine: a potentially neurotoxic amphetamine analogue

Psychedelic Therapy: A Primer for Primary Care Clinicians-3,4-Methylenedioxy-methamphetamine (MDMA)

BACKGROUND

After becoming notorious for its use as a party drug in the 1980s, 3,4-methylenedioxy-methampetamine (MDMA), also known by its street names "molly" and "ecstasy," has emerged as a powerful treatment for post-traumatic stress disorder (PTSD).

AREAS OF UNCERTAINTY

There are extensive data about the risk profile of MDMA. However, the literature is significantly biased. Animal models demonstrating neurotoxic or adverse effects used doses well beyond the range that would be expected in humans (up to 40 mg/kg in rats compared with roughly 1-2 mg/kg in humans). Furthermore, human samples often comprise recreational users who took other substances in addition to MDMA, in uncontrolled settings.

THERAPEUTIC ADVANCES

Phase III clinical trials led by the Multidisciplinary Association for Psychedelic Studies (MAPS) have shown that MDMA-assisted psychotherapy has an effect size of d = 0.7-0.91, up to 2-3 times higher than the effect sizes of existing antidepressant treatments. 67%-71% of patients who undergo MDMA-assisted psychotherapy no longer meet the diagnostic criteria for PTSD within 18 weeks. We also describe other promising applications of MDMA-assisted psychotherapy for treating alcohol use disorder, social anxiety, and other psychiatric conditions.

LIMITATIONS

Thus far, almost all clinical trials on MDMA have been sponsored by a single organization, MAPS. More work is needed to determine whether MDMA-assisted therapy is more effective than existing nonpharmacological treatments such as cognitive behavioral therapy.

CONCLUSIONS

Phase III trials suggest that MDMA is superior to antidepressant medications for treating PTSD. Now that MAPS has officially requested the Food and Drug Administration to approve MDMA as a treatment for PTSD, legal MDMA-assisted therapy may become available as soon as 2024.

Serotonin 2C receptors are also important in head-twitch responses in male mice

RATIONALE

Serotonergic psychedelics exert their effects via their high affinity for serotonin (5-HT) receptors, particularly through activating 5-HT2A receptors (5-HT2AR), employing the frontal cortex-dependent head-twitch response (HTR). Although universally believed to be so, studies have not yet fully ascertained whether 5-HT2AR activation is the sole initiator of these psychedelic effects. This is because not all 5-HT2AR agonists exhibit similar pharmacologic properties.

OBJECTIVE

This study aims to identify and discriminate the roles of 5-HT2AR and 5-HT2CR in the HTR induced by Methallylescaline (MAL) and 4-Methyl-2,5,β-trimethoxyphenethylamine (BOD) in male mice. Also, an analysis of their potential neurotoxic properties was evaluated.

METHODS

Male mice treated with MAL and BOD were evaluated in different behavioral paradigms targeting HTR and neurotoxicity effects. Drug affinity, pharmacological blocking, and molecular analysis were also conducted to support the behavioral findings. The HTR induced by DOI has been extensively characterized in male mice, making it a good positive control for this study, specifically for comparing the pharmacological effects of our test compounds.

RESULTS

The activation of 5-HT2CR, alone or in concert with 5-HT2AR, produces a comparable degree of HTRs (at a dose of 1 mg·kg-1), with divergent 5-HT2CR- and 5-HT2AR-Gqα11-mediated signaling and enhanced neurotoxic properties (at a dose of 30 mg·kg-1) coupled with activated pro-inflammatory cytokines. These findings show these compounds' potential psychedelic and neurotoxic effects in male mice.

CONCLUSION

These findings showed that while 5-HT2AR is the main initiator of HTR, the 5-HT2CR also has a distinct property that renders it effective in inducing HTR in male mice.

Psilocybin and MDMA for the treatment of trauma-related psychopathology

This review examines the role of trauma in psychiatric morbidity and analogous psychoneurobiological changes. Trauma is a necessary criterion for Post-Traumatic Stress Disorder (PTSD), however, trauma history is highly correlated with a variety of psychiatric conditions. Some evidence suggests that Major Depressive Disorder (MDD) is the most common psychiatric condition that arises following trauma. Approximately 50% of PTSD cases present with co-morbid MDD. Overlapping symptomatology and neurobiology between these conditions underlie the debate over whether these phenomena result from problematic nosology or whether comorbid MDD + PTSD is a distinct phenotype of trauma-related psychopathology. Regardless, similar treatment approaches have been employed historically, with varying success. The drug-assisted psychotherapy treatment model, which combines pharmacological and psychotherapeutic approaches, is currently being trialled as a novel treatment approach in psychiatry. Both psilocybin- and 3,4-Methylenedioxymethamphetamine (MDMA)-assisted psychotherapy have received Food and Drug Administration 'breakthrough therapy' designation for the treatment of resistant MDD and PTSD, respectively. This paper reviews the therapeutic rationale of both psilocybin and MDMA for treating both trauma-related MDD and PTSD.

Dark Classics in Chemical Neuroscience: 3,4-Methylenedioxymethamphetamine

Better known as "ecstasy", 3,4-methylenedioxymethamphetamine (MDMA) is a small molecule that has played a prominent role in defining the ethos of today's teenagers and young adults, much like lysergic acid diethylamide (LSD) did in the 1960s. Though MDMA possesses structural similarities to compounds like amphetamine and mescaline, it produces subjective effects that are unlike any of the classical psychostimulants or hallucinogens and is one of the few compounds capable of reliably producing prosocial behavioral states. As a result, MDMA has captured the attention of recreational users, the media, artists, psychiatrists, and neuropharmacologists alike. Here, we detail the synthesis of MDMA as well as its pharmacology, metabolism, adverse effects, and potential use in medicine. Finally, we discuss its history and why it is perhaps the most important compound for the future of psychedelic science-having the potential to either facilitate new psychedelic research initiatives, or to usher in a second Dark Age for the field.

Are ecstasy induced serotonergic alterations overestimated for the majority of users?

BACKGROUND

Neuroimaging studies imply that the regular use of ±3,4-methylenedioxymethamphetamine (MDMA), the major constituent of ecstasy pills, alters the brain's serotonergic system in a dose-dependent manner. However, the relevance of these findings remains unclear due to limited knowledge about the ecstasy/MDMA use pattern of real-life users.

AIMS

We examined the representativeness of ecstasy users enrolled in neuroimaging studies by comparing their ecstasy use habits with the use patterns of a large, international sample.

METHODS

A systematic literature search revealed 10 imaging studies that compare serotonin transporter levels in recreational ecstasy users to matched controls. To characterize the ecstasy use patterns we relied on the Global Drug Survey, the world's largest self-report database on drug use. The basis of the dose comparison were the Usual Amount (pills/session), Use Frequency (sessions/month) and Dose Intensity (pills/year) variables.

RESULTS

Both the average Usual Amount (pills/session) and Use Frequency (sessions/month) of neuroimaging study participants corresponded to the top 5-10% of the Global Drug Survey sample and imaging participants, on average, consumed 720% more pills over a year than the Global Drug Survey participants.

CONCLUSIONS

Our findings suggest that the serotonin brain imaging literature has focused on unusually heavy ecstasy use and therefore the conclusions from these studies are likely to overestimate the extent of serotonergic alterations experienced by the majority of people who use ecstays.

REVIEW ■ : Long-lasting Effects of Recreational Drugs of Abuse on the Central Nervous System

Although a wealth of knowledge exists regarding the acute pharmacological effects of recreational drugs on the CNS, much less is known about the long-term toxic effects of recreational drugs on the CNS. Recent findings in nonhuman primates treated with amphetamine analogs, such as ±3,4-methylenedioxymetham phetamine (MDMA), indicate that these drugs can produce long-lasting, probably permanent, changes in brain serotonin innervation. Similarly, animals treated with phencyclidine (PCP) and related drugs develop neurodegenerative changes in selected brain regions. It seems clear, then, that some psychoactive drugs have the potential to produce persistent changes in CNS structure and, possibly, function. The goal of this article is to summarize current knowledge regarding the long-term effects of several popular recreational drugs, including MDMA and related amphetamine analogs, cocaine, marijuana, alcohol, PCP, lysergic acid (LSD), and opiates. Gaps in the current knowledge base are identified, and areas ripe for future research efforts are suggested. NEUROSCIENTIST 3:399-411, 1997

3,4-methylenedioxymethamphetamine increases excitability in the dentate gyrus: role of 5HT2A receptor-induced PGE2 signaling

3,4-methylenedioxymethamphetamine (MDMA) is a widely abused psychostimulant, which causes release of serotonin in various forebrain regions. Recently, we reported that MDMA increases extracellular glutamate concentrations in the dentate gyrus, via activation of 5HT2A receptors. We examined the role of prostaglandin signaling in mediating the effects of 5HT2A receptor activation on the increases in extracellular glutamate and the subsequent long-term loss of parvalbumin interneurons in the dentate gyrus caused by MDMA. Administration of MDMA into the dentate gyrus of rats increased PGE2 concentrations which was prevented by coadministration of MDL100907, a 5HT2A receptor antagonist. MDMA-induced increases in extracellular glutamate were inhibited by local administration of SC-51089, an inhibitor of the EP1 prostaglandin receptor. Systemic administration of SC-51089 during injections of MDMA prevented the decreases in parvalbumin interneurons observed 10 days later. The loss of parvalbumin immunoreactivity after MDMA exposure coincided with a decrease in paired-pulse inhibition and afterdischarge threshold in the dentate gyrus. These changes were prevented by inhibition of EP1 and 5HT2A receptors during MDMA. Additional experiments revealed an increased susceptibility to kainic acid-induced seizures in MDMA-treated rats, which could be prevented with SC51089 treatments during MDMA exposure. Overall, these findings suggest that 5HT2A receptors mediate MDMA-induced PGE2 signaling and subsequent increases in glutamate. This signaling mediates parvalbumin cell losses as well as physiologic changes in the dentate gyrus, suggesting that the lack of the inhibition provided by these neurons increases the excitability within the dentate gyrus of MDMA-treated rats. We hypothesized that the widely abused psychostimulant MDMA causes a loss of parvalbumin (PV) cells and increases excitability in the dentate gyrus. MDMA increases serotonin (5HT) release and activates 5HT2A receptors. The increased activation of 5HT2A receptors promotes the production of prostaglandin E2 (PGE2) and subsequent activation of EP1 receptors in the dentate gyrus. EP1 receptor activation leads to eventual excitotoxicity and loss of PV interneurons resulting in reduced inhibition and lowered seizure threshold resulting in increased seizure susceptibility.

Effect of MDMA-Induced Axotomy on the Dorsal Raphe Forebrain Tract in Rats: An In Vivo Manganese-Enhanced Magnetic Resonance Imaging Study

3,4-Methylenedioxymethamphetamine (MDMA), also known as “Ecstasy”, is a common recreational drug of abuse. Several previous studies have attributed the central serotonergic neurotoxicity of MDMA to distal axotomy, since only fine serotonergic axons ascending from the raphe nucleus are lost without apparent damage to their cell bodies. However, this axotomy has never been visualized directly in vivo. The present study examined the axonal integrity of the efferent projections from the midbrain raphe nucleus after MDMA exposure using in vivo manganese-enhanced magnetic resonance imaging (MEMRI). Rats were injected subcutaneously six times with MDMA (5 mg/kg) or saline once daily. Eight days after the last injection, manganese ions (Mn²⁺) were injected stereotactically into the raphe nucleus, and a series of MEMRI images was acquired over a period of 38 h to monitor the evolution of Mn²⁺-induced signal enhancement across the ventral tegmental area, the medial forebrain bundle (MFB), and the striatum. The MDMA-induced loss of serotonin transporters was clearly evidenced by immunohistological staining consistent with the Mn²⁺-induced signal enhancement observed across the MFB and striatum. MEMRI successfully revealed the disruption of the serotonergic raphe-striatal projections and the variable effect of MDMA on the kinetics of Mn²⁺ accumulation in the MFB and striatum.

MDMA for the treatment of mood disorder: all talk no substance?

BACKGROUND

Unipolar depression is the third highest contributor to the global burden of disease, yet current pharmacotherapies typically take about 6 weeks to have an effect. A rapid-onset agent is an attractive prospect, not only to alleviate symptoms before first-line antidepressants display therapeutic action, but as a further treatment option in nonresponsive cases. It has been suggested that 3,4-methylene-dioxymethamphetamine (MDMA) could play a part in the treatment of depression, either as a rapid-onset pharmacological agent or as an adjunct to psychotherapy. Whilst these hypotheses are in keeping with the monoamine theory of depression and the principles surrounding psychotherapy, explicit experimental evidence of an antidepressant effect of MDMA has rarely been established.

AIMS

To address the hypothesis surrounding MDMA as a rapid-onset antidepressant by examining pharmacological, psychological and behavioural studies. We consider whether this therapy could be safe by looking at the translation of neurotoxicity data from animals to humans.

METHOD

A literature review of the evidence supporting this hypothesis was performed.

CONCLUSIONS

The pharmacology of MDMA offers a promising target as a rapid-onset agent and MDMA is currently being investigated for use in psychotherapy in anxiety disorders; translation from these studies for use in depression may be possible. However, experimental evidence and safety analysis are insufficient to confirm or reject this theory at present.

Effects of ecstasy on cooperative behaviour and perception of trustworthiness: a naturalistic study

BACKGROUND

Acute recreational use of 3,4-methylenedioxymethamphetamine (MDMA; 'ecstasy') can promote pro-social effects which may alter interpersonal perceptions.

AIMS

To explore such effects, this study investigated whether acute recreational use of ecstasy was associated with changes in individual perception of trustworthiness of people's faces and co-operative behaviours.

METHOD

An independent group, repeated measures design was used in which 17 ecstasy users were tested on the night of drug use (day 0) and again three days later (day 3); 22 controls were tested on parallel days. On each day, participants rated the trustworthiness of 66 faces, carried out three co-operative behaviour tasks (public good; dictator; ultimatum game) and completed mood self-ratings.

RESULTS

Acute ecstasy use was associated with increased face trustworthiness ratings and increased cooperative behaviour on the dictator and ultimatum games; on day 3 there were no group differences on any task. Self-ratings showed the standard acute ecstasy effects (euphoria, energy, jaw clenching) with negative effects (less empathy, compassion, more distrust, hostility) emerging on day 3.

CONCLUSIONS

Our findings of increased perceived trustworthiness and co-operative behaviours following use of ecstasy suggest that a single dose of the drug enhances aspects of empathy. This may in turn contribute to its popularity as a recreational drug and potentially to its enhancement of the therapeutic alliance in psychotherapy.

5-hydroxytryptamine- and dopamine-releasing effects of ring-substituted amphetamines on rat brain: a comparative study using in vivo microdialysis

Using in vivo microdialysis, a comparative study was conducted to examine the effects of amphetamine-related compounds (methamphetamine, MAP; 3,4-methylenedioxymethamphetamine, MDMA; p-methoxyamphetamine, PMA; p-methoxymethamphetamine, PMMA; 4-methylthioamphetamine, 4-MTA; 3,4,5-trimethoxyamphetamine, TMA; 2,5-dimethoxy-4-iodoamphetamine, DOI) on extracellular levels of serotonin (5-HT) and dopamine (DA). Dialysates were assayed using HPLC equipped with electrochemical detector following i.p. administration with each drug at a dose of 5 mg/kg. MAP was found to drastically and rapidly increase 5-HT and DA levels (870% and 1460%, respectively). PMA, PMMA, and 4-MTA slightly increased DA levels (150-290%) but remarkably increased 5-HT levels (540-900%). In contrast, TMA and DOI caused no detectable changes in levels of both monoamines. We observed that the potent DA-releasing action of MAP was remarkably decreased by introduction of methoxy or methylthio group at the para position (MAP vs. PMMA or 4-MTA), but introduction of two additional adjacent methoxy groups into PMA totally abolished its 5-HT-/DA-releasing action (PMA vs. TMA). In addition, para-mono-substituted compounds inhibited both monoamine oxidase (MAO) enzymes more strongly than other compounds; PMA and 4-MTA exhibited submicromolar IC50 values for MAO-A. On the other hand, TMA scarcely affected the activity of both MAO enzymes as well as extracellular levels of 5-HT and DA. In this comparative study, MDMA, PMA, and 4-MTA functioned similar to PMMA, a typical empathogen; these findings therefore could be helpful in clarifying the psychopharmacological properties of amphetamine-related, empathogenic designer drugs.

Effects of long-term exposure of 3,4-methylenedioxymethamphetamine (MDMA; "ecstasy") on neuronal transmitter transport, brain immuno-regulatory systems and progression of experimental periodontitis in rats

The present study was designed to investigate the effects of long-term exposure (4 weeks) to the widely used narcotic drug and putative neurotoxicant 3,4-methylenedioxymetamphetamine (MDMA; "ecstasy") on neuronal transmitter transport and progression of experimental periodontitis in male Wistar rats. The rats were exposed to MDMA (10mg/kg/day i.p.) or saline five days a week for four consecutive weeks. Exposure to MDMA induced a significant reduction in the synaptosomal reuptake of serotonin, while the uptake of dopamine was significantly increased 24h after the last injection of MDMA. In contrast, the synaptosomal uptake of noradrenaline and the vesicular uptake through the vesicular monoamine transporter 2 were not affected. In the experiments of periodontitis development, ligature-induced periodontitis was induced three days prior to MDMA administration. Compared to controls, MDMA-treated rats developed significantly more periodontitis. In conclusion, our results show that long-term exposure to MDMA affects the serotonergic and dopaminergic transport systems in the rat brain and increased the susceptibility to the psychosomatic ailment periodontitis following disturbances of brain immune-regulatory systems. These results are interesting with respect to recent research showing that changes in neurotransmitter signalling may alter the reactivity of brain-controlled immunoregulatory systems controlling pathogenic microorganisms colonizing mucosal surfaces.

Contribution of impulsivity and novelty-seeking to the acquisition and maintenance of MDMA self-administration

It has been suggested that the response to novelty and impulsivity predict the latency to acquisition and maintenance of drug self-administration, respectively. The aim of this study was to examine the relationship between these two traits and (1) the latency to acquisition and (2) maintenance (drug-seeking) of 3,4-methylenedioxymethamphetamine (MDMA) self -administration. Impulsivity, measured as premature responding on the five-choice serial reaction time task (5-CSRTT), and novelty-seeking, measured as the locomotor response in a novel environment, were measured prior to self-administration. Latency to acquisition was determined as the number of test sessions required to self-administer an initial criterion of 90 infusions of 1.0 mg/kg/infusion, as well as an additional 150 infusions of 0.5 mg/kg/infusion MDMA. For some rats, the ability of MDMA [0, 5.0 or 10.0 mg/kg, intraperitoneal (IP)] to produce drug-seeking was subsequently measured, and for others, impulsivity was again measured following self-administration. Novelty-seeking was not significantly correlated with either the acquisition or drug-seeking measures of MDMA self-administration. Impulsivity was not significantly correlated with the latency to acquire self-administration of MDMA, but was significantly and positively correlated with the magnitude of MDMA-produced drug-seeking. Furthermore, MDMA self-administration produced a number of notable, but transient, deficits in the 5-CSRTT; there was an increase in omission rate and a delayed increase in premature responses in particular. These findings suggest that impulsivity, but not sensation seeking, might be a risk factor for the development of compulsive drug-seeking following withdrawal from MDMA self-administration.

Parallel changes in serotonin levels in brain and blood following acute administration of MDMA

Recent studies have demonstrated a similar acute effect of 3,4- methylenedioxymethamphetamine (MDMA) in blood platelets and brain tissue via action on the serotonin transporter. To investigate the validity of blood serotonin as a peripheral marker for central serotonin in this regard, we administered MDMA (20 mg/kg i.p.) to rats and observed a parallel decrease in serotonin levels in the frontal cortex and blood at 2 h (63% and 46% respectively) with some recovery evident at 8 h (42% and 38%) and more so at 18 h (19% and 24% below control levels). Administration of a tryptophan supplement (82.5 mg/kg p.o.) to naïve rats produced parallel increases in serotonin levels 2 h later in the frontal cortex (39%) and blood (26%). Following MDMA administration, the same dose of tryptophan caused a smaller (26%) rise in brain serotonin whereas in blood it had no effect. We conclude that blood serotonin is a useful marker for brain serotonin levels in the rat following acute administration of MDMA and this finding highlights the possible use of platelet serotonin as a marker for brain serotonin in human studies involving MDMA.

Sustained recreational use of ecstasy is associated with altered pre and postsynaptic markers of serotonin transmission in neocortical areas: a PET study with [¹¹C]DASB and [¹¹C]MDL 100907

3,4-Methylenedioxymethamphetamine (MDMA), the main psychoactive component of the recreational drug ecstasy, is a potent serotonin (5-HT) releaser. In animals, MDMA induces 5-HT depletion and toxicity in 5-HT neurons. The aim of this study was to investigate both presynaptic (5-HT transporter, SERT) and postsynaptic (5-HT(2A) receptor) markers of 5-HT transmission in recently abstinent chronic MDMA users compared with matched healthy controls. We hypothesized that MDMA use is associated with lower SERT density and concomitant upregulation of 5-HT(2A) receptors. Positron emission tomography studies using the SERT ligand [¹¹C]DASB and the 5-HT(2A) receptor ligand [¹¹C]MDL 100907 were evaluated in 13 current and recently detoxified MDMA users and 13 matched healthy controls. MDMA users reported a mean duration of ecstasy use of 8 years, regular exposure, and at least 2 weeks of abstinence before the scans. SERT and 5-HT(2A) receptor availability (binding potential, BP(ND)) were analyzed with a two-tissue compartment model with arterial input function. Current recreational MDMA use was significantly associated with lower SERT BP(ND) and higher 5-HT(2A) receptor BP(ND) in cortical, but not subcortical regions. Decreased SERT BP(ND) was regionally associated with upregulated 5-HT(2A) receptor BP(ND). In light of the animal literature, the most parsimonious interpretation is that repeated exposure to MDMA in humans, even in moderate amounts, leads to damage in 5-HT neuron terminals innervating the cortex. Alterations in mood, cognition, and impulse control associated with these changes might contribute to sustain MDMA use. The reversibility of these changes upon abstinence remains to be firmly established.

Toxicity of amphetamines: an update

Amphetamines represent a class of psychotropic compounds, widely abused for their stimulant, euphoric, anorectic, and, in some cases, emphathogenic, entactogenic, and hallucinogenic properties. These compounds derive from the β-phenylethylamine core structure and are kinetically and dynamically characterized by easily crossing the blood-brain barrier, to resist brain biotransformation and to release monoamine neurotransmitters from nerve endings. Although amphetamines are widely acknowledged as synthetic drugs, of which amphetamine, methamphetamine, and 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) are well-known examples, humans have used natural amphetamines for several millenniums, through the consumption of amphetamines produced in plants, namely cathinone (khat), obtained from the plant Catha edulis and ephedrine, obtained from various plants in the genus Ephedra. More recently, a wave of new amphetamines has emerged in the market, mainly constituted of cathinone derivatives, including mephedrone, methylone, methedrone, and buthylone, among others. Although intoxications by amphetamines continue to be common causes of emergency department and hospital admissions, it is frequent to find the sophism that amphetamine derivatives, namely those appearing more recently, are relatively safe. However, human intoxications by these drugs are increasingly being reported, with similar patterns compared to those previously seen with classical amphetamines. That is not surprising, considering the similar structures and mechanisms of action among the different amphetamines, conferring similar toxicokinetic and toxicological profiles to these compounds. The aim of the present review is to give an insight into the pharmacokinetics, general mechanisms of biological and toxicological actions, and the main target organs for the toxicity of amphetamines. Although there is still scarce knowledge from novel amphetamines to draw mechanistic insights, the long-studied classical amphetamines-amphetamine itself, as well as methamphetamine and MDMA, provide plenty of data that may be useful to predict toxicological outcome to improvident abusers and are for that reason the main focus of this review.

The Nature of 3, 4-Methylenedioxymethamphetamine (MDMA)-Induced Serotonergic Dysfunction: Evidence for and Against the Neurodegeneration Hypothesis

High doses of the recreational drug 3,4-methylenedioxymethamphetamine (MDMA, "Ecstasy") have been well-documented to reduce the expression of serotonergic markers in several forebrain regions of rats and nonhuman primates. Neuroimaging studies further suggest that at least one of these markers, the plasma membrane serotonin transporter (SERT), may also be reduced in heavy Ecstasy users. Such effects, particularly when observed in experimental animal models, have generally been interpreted as reflecting a loss of serotonergic fibers and terminals following MDMA exposure. This view has been challenged, however, based on the finding that MDMA usually does not elicit glial cell reactions known to occur in response to central nervous system (CNS) damage. The aim of this review is to address both sides of the MDMA-neurotoxicity controversy, including recent findings from our laboratory regarding the potential of MDMA to induce serotonergic damage in a rat binge model. Our data add to the growing literature implicating neuroregulatory mechanisms underlying MDMA-induced serotonergic dysfunction and questioning the need to invoke a degenerative response to explain such dysfunction.

Methylenedioxymethamphetamine (MDMA, 'Ecstasy'): Neurodegeneration versus Neuromodulation

The amphetamine analogue 3,4-methylenedioxymethamphetamine (MDMA, ‘ecstasy’) is widely abused as a recreational drug due to its unique psychological effects. Of interest, MDMA causes long-lasting deficits in neurochemical and histological markers of the serotonergic neurons in the brain of different animal species. Such deficits include the decline in the activity of tryptophan hydroxylase in parallel with the loss of 5-HT and its main metabolite 5-hydoxyindoleacetic acid (5-HIAA) along with a lower binding of specific ligands to the 5-HT transporters (SERT). Of concern, reduced 5-HIAA levels in the CSF and SERT density have also been reported in human ecstasy users, what has been interpreted to reflect the loss of serotonergic fibers and terminals. The neurotoxic potential of MDMA has been questioned in recent years based on studies that failed to show the loss of the SERT protein by western blot or the lack of reactive astrogliosis after MDMA exposure. In addition, MDMA produces a long-lasting down-regulation of SERT gene expression; which, on the whole, has been used to invoke neuromodulatory mechanisms as an explanation to MDMA-induced 5-HT deficits. While decreased protein levels do not necessarily reflect neurodegeneration, the opposite is also true, that is, neuroregulatory mechanisms do not preclude the existence of 5-HT terminal degeneration.

The ugly side of amphetamines: short- and long-term toxicity of 3,4-methylenedioxymethamphetamine (MDMA, 'Ecstasy'), methamphetamine and D-amphetamine

Amphetamine ('Speed'), methamphetamine ('Ice') and its congener 3,4-methylenedioxymethamphetamine (MDMA; 'Ecstasy') are illicit drugs abused worldwide for their euphoric and stimulant effects. Despite compelling evidence for chronic MDMA neurotoxicity in animal models, the physiological consequences of such toxicity in humans remain unclear. In addition, distinct differences in the metabolism and pharmacokinetics of MDMA between species and different strains of animals prevent the rationalisation of realistic human dose paradigms in animal studies. Here, we attempt to review amphetamine toxicity and in particular MDMA toxicity in the pathogenesis of exemplary human pathologies, independently of confounding environmental factors such as poly-drug use and drug purity.

Synthesis and neurotoxicity profile of 2,4,5-trihydroxymethamphetamine and its 6-(N-acetylcystein-S-yl) conjugate

The purpose of the present study was to determine if trihydroxymethamphetamine (THMA), a metabolite of methylenedioxymethamphetamine (MDMA, "ecstasy"), or its thioether conjugate, 6-(N-acetylcystein-S-yl)-2,4,5-trihydroxymethamphetamine (6-NAC-THMA), play a role in the lasting effects of MDMA on brain serotonin (5-HT) neurons. To this end, novel high-yield syntheses of THMA and 6-NAC-THMA were developed. Lasting effects of both compounds on brain serotonin (5-HT) neuronal markers were then examined. A single intraventricular injection of THMA produced a significant lasting depletion of regional rat brain 5-HT and 5-hydroxyindoleacetic acid (5-HIAA), consistent with previous reports that THMA harbors 5-HT neurotoxic potential. The lasting effect of THMA on brain 5-HT markers was blocked by the 5-HT uptake inhibitor fluoxetine, indicating that persistent effects of THMA on 5-HT markers, like those of MDMA, are dependent on intact 5-HT transporter function. Efforts to identify THMA in the brains of animals treated with a high, neurotoxic dose (80 mg/kg) of MDMA were unsuccessful. Inability to identify THMA in the brains of these animals was not related to the unstable nature of the THMA molecule because exogenous THMA administered intracerebroventricularly could be readily detected in the rat brain for several hours. The thioether conjugate of THMA, 6-NAC-THMA, led to no detectable lasting alterations of cortical 5-HT or 5-HIAA levels, indicating that it lacks significant 5-HT neurotoxic activity. The present results cast doubt on the role of either THMA or 6-NAC-THMA in the lasting serotonergic effects of MDMA. The possibility remains that different conjugated forms of THMA or oxidized cyclic forms (e.g., the indole of THMA) play a role in MDMA-induced 5-HT neurotoxicity in vivo.

Enhanced hippocampal long-term potentiation following repeated MDMA treatment in Dark-Agouti rats

In rats and primates, (±)3,4-Methylenedioxymethamphetamine (MDMA, ecstasy) produces both long-lasting damage to serotonergic axons and memory impairment. Our objective was to determine effects of neurotoxic dose of MDMA on long-term potentiation (LTP) in hippocampal area CA1 in Dark-Agouti (DA) rats. One week after neurotoxic MDMA treatment in vivo (12.5mg/kg i.p., once a week, per three weeks), serotonergic deficit was evident in hippocampal slices as 56.3% reduction in 5-HT content (p=0.04) and as 68.4% reduction in the effect of endogenous 5-HT release on synaptic neurotransmission (p<0.01). In hippocampal slices from the same animals, LTP was on average 46% greater than that observed in sham-treated controls (42.9 ± 3.5%; n=12 vs. 29.2 ± 3.2%; n=12; p<0.01). Non-neurotoxic dose of MDMA (12.5 mg/kg, i.p., one time) did not change LTP one week after the treatment, suggesting correlation between serotonergic deficit and enhanced synaptic plasticity. We conclude that MDMA-induced impairment of learning and memory is not a consequence of hippocampal LTP inhibition.

Decreased cerebral cortical serotonin transporter binding in ecstasy users: a positron emission tomography/[(11)C]DASB and structural brain imaging study

Animal data indicate that the recreational drug ecstasy (3,4-methylenedioxymethamphetamine) can damage brain serotonin neurons. However, human neuroimaging measurements of serotonin transporter binding, a serotonin neuron marker, remain contradictory, especially regarding brain areas affected; and the possibility that structural brain differences might account for serotonin transporter binding changes has not been explored. We measured brain serotonin transporter binding using [(11)C] N,N-dimethyl-2-(2-amino-4-cyanophenylthio) benzylamine in 50 control subjects and in 49 chronic (mean 4 years) ecstasy users (typically one to two tablets bi-monthly) withdrawn from the drug (mean 45 days). A magnetic resonance image for positron emission tomography image co-registration and structural analyses was acquired. Hair toxicology confirmed group allocation but also indicated use of other psychoactive drugs in most users. Serotonin transporter binding in ecstasy users was significantly decreased throughout all cerebral cortices (range -19 to -46%) and hippocampus (-21%) and related to the extent of drug use (years, maximum dose), but was normal in basal ganglia and midbrain. Substantial overlap was observed between control and user values except for insular cortex, in which 51% of ecstasy user values fell below the lower limit of the control range. Voxel-based analyses confirmed a caudorostral gradient of cortical serotonin transporter binding loss with occipital cortex most severely affected. Magnetic resonance image measurement revealed no overall regional volume differences between groups; however, a slight left-hemispheric biased cortical thinning was detected in methamphetamine-using ecstasy users. The serotonin transporter binding loss was not related to structural changes or partial volume effect, use of other stimulant drugs, blood testosterone or oestradiol levels, major serotonin transporter gene promoter polymorphisms, gender, psychiatric status, or self-reported hyperthermia or tolerance. The ecstasy group, although 'grossly behaviourally normal', reported subnormal mood and demonstrated generally modest deficits on some tests of attention, executive function and memory, with the latter associated with serotonin transporter decrease. Our findings suggest that the 'typical'/low dose (one to two tablets/session) chronic ecstasy-polydrug user might display a highly selective mild to marked loss of serotonin transporter in cerebral cortex/hippocampus in the range of that observed in Parkinson's disease, which is not gender-specific or completely accounted for by structural brain changes, recent use of other drugs (as assessed by hair analyses) or other potential confounds that we could address. The striking sparing of serotonin transporter-rich striatum (although possibly affected in 'heavier' users) suggests that serotonergic neurons innervating cerebral cortex are more susceptible, for unknown reasons, to ecstasy than those innervating subcortical regions and that behavioural problems in some ecstasy users during abstinence might be related to serotonin transporter changes limited to cortical regions.

Behavioral, thermal and neurochemical effects of acute and chronic 3,4-methylenedioxymethamphetamine ("Ecstasy") self-administration

3,4-Methylenedioxymethamphetamine (MDMA) is a popular methamphetamine derivative associated with young adults and all-night dance parties. However, the enduring effects of MDMA at voluntary intake levels have not been extensively investigated. In this study, MDMA-influenced behaviors and core temperatures were assessed over the course of 20 daily MDMA self-administration sessions in rats. In vivo microdialysis techniques were used in a subsequent MDMA challenge test session to determine extracellular nucleus accumbens dopamine (NAcc DA) and serotonin (5-HT) levels in MDMA-experienced and naïve animals before and after a self-administered MDMA injection (3.0mg/kg, i.v.). During self-administration sessions, gradual and significant increases in MDMA intake and MDMA-stimulated locomotor activity were observed across sessions. Core temperature significantly decreased during initial MDMA sessions, but was unaltered by the last 10 sessions. In the MDMA challenge test, MDMA-naïve rats showed significantly higher NAcc 5-HT responses compared to MDMA-experienced rats, though MDMA experience did not affect the magnitude of NAcc DA response. The overall findings suggest that changes in MDMA-induced responses over the course of increasing levels of drug exposure may reflect the development of tolerance to a number of MDMA effects.

Neurotoxicity of substituted amphetamines: Molecular and cellular mechanisms

The amphetamines, including amphetamine (AMPH), methamphetamine (METH) and 3,4-methylenedioxymethamphetamine (MDMA), are among abused drugs in the US and throughout the world. Their abuse is associated with severe neurologic and psychiatric adverse events including the development of psychotic states. These neuropsychiatric complications might, in part, be related to drug-induced neurotoxic effects, which include damage to dopaminergic and serotonergic terminals, neuronal apoptosis, as well as activated astroglial and microglial cells in the brain. The purpose of the present review is to summarize the toxic effects of AMPH, METH and MDMA. The paper also presents some of the factors that are thought to underlie this toxicity. These include oxidative stress, hyperthermia, excitotoxicity and various apoptotic pathways. Better understanding of the cellular and molecular mechanisms involved in their toxicity should help to generate modern therapeutic approaches to prevent or attenuate the long-term consequences of amphetamine use disorders in humans.

The effect of catecholamine depletion by alpha-methyl-para-tyrosine on measures of cognitive performance and sleep in abstinent MDMA users

(+/-) 3, 4-Methylenedioxymethamphetamine (MDMA) is a popular recreational drug of abuse and a brain serotonin (5-HT) neurotoxin in animals. Growing evidence suggests that humans who use MDMA recreationally can also develop 5-HT neurotoxic injury, although functional consequences have been difficult to identify. Twenty-five abstinent MDMA users and 23 non-MDMA using controls were studied to determine whether pharmacologic depletion of brain catecholamines by alpha-methyl-para-tyrosine (AMPT) would differentially effect MDMA users on measures of cognition and sleep, two processes dually modulated by brain serotonergic and catecholaminergic neurons. During a 5-day in-patient study, all subjects underwent formal neuropsychiatric testing, repeated computerized cognitive testing, and all-night sleep studies. At baseline, MDMA users had performance deficits on tasks of verbal and visuospatial working memory and displayed increased behavioral impulsivity on several computerized tasks, reflecting a tendency to perform quickly at the expense of accuracy. Baseline sleep architecture was also altered in abstinent MDMA users compared to controls. AMPT produced differential effects in MDMA users compared to controls on several cognitive and sleep measures. Differences in cognitive performance, impulsivity, and sleep were significantly correlated with MDMA use. These data extend findings from earlier studies demonstrating cognitive deficits, behavioral impulsivity, and sleep alterations in abstinent MDMA users, and suggest that lasting effects of MDMA lead to alterations in the ability to modulate behaviors reciprocally influenced by 5-HT and catecholamines. More research is needed to determine potential relationships between sleep abnormalities, cognitive deficits and impulsive behavior in abstinent MDMA users.

Hug drug or thug drug? Ecstasy use and aggressive behavior

While clinical studies have established a link between aggression and ecstasy (3,4-methylenedioxymeth-amphetamine [MDMA]), no research has attempted to explore how this link manifests itself in behavioral outcomes. In this research we examine the effects of ecstasy on aggressive and violent behavior in a sample of active users. Data were collected from 260 ecstasy users in Atlanta, Georgia. Data analysis included ordered logit regression to examine the likelihood of engaging in aggressive behavior, controlling for key predictors of aggression independent of ecstasy use. Our results indicate that those with a higher prevalence of lifetime ecstasy use exhibit higher levels of aggressive and violent behavior. However, the effect of lifetime ecstasy use differs by levels of low self-control as a measure of propensity for aggression. Those who exhibit low self-control are more affected by ecstasy use than those who do not in terms of aggression. Our findings add an important dimension to our current knowledge about the relationship between aggression and ecstasy.

Persistent cerebrovascular effects of MDMA and acute responses to the drug

Acutely, 3,4,-methylenedioxymethamphetamine (MDMA) induces cerebrovascular dysfunction [Quate et al., (2004)Psychopharmacol., 173, 287-295]. In the longer term the same single dose results in depletion of 5-hydroxytrptamine (5-HT) nerve terminals. In this study we examined the cerebrovascular consequences of this persistent neurodegeneration, and the acute effects of subsequent MDMA exposure, upon the relationship that normally exists between local cerebral blood flow (LCBF) and local cerebral glucose utilization (LCMRglu). Dark agouti (DA) rats were pre-treated with 15 mg/kg i.p. MDMA or saline. Three weeks later, rats from each pre-treatment group were treated with an acute dose of MDMA (15 mg/kg i.p.) or saline. Quantitative autoradiographic imaging was used to measure LCBF or LCMRglu with [(14)C]-iodoantipyrine and [(14)C]-2-deoxyglucose, respectively. Serotonergic terminal depletion was assessed using radioligand binding with [(3)H]-paroxetine and immunohistochemistry. Three weeks after MDMA pre-treatment there were significant reductions in densities of 5-HT transporter (SERT)-positive fibres (-46%) and [(3)H]-paroxetine binding (-47%). In animals pre-treated with MDMA there were widespread significant decreases in LCMRglu, but no change in LCBF indicating a persistent loss of cerebrovascular constrictor tone. In both pre-treatment groups, acute MDMA produced significant increases in LCMRglu, while LCBF was significantly decreased. In 50% of MDMA-pre-treated rats, random areas of focal hyperaemia indicated a loss of autoregulatory capacity in response to MDMA-induced hypertension. These results suggest that cerebrovascular regulatory dysfunction resulting from acute exposure to MDMA is not diminished by previous exposure, despite a significant depletion in 5-HT terminals. However, there may be a sub-population, or individual circumstances, in which this dysfunction develops into a condition that might predispose to stroke.

Memory function and serotonin transporter promoter gene polymorphism in ecstasy (MDMA) users

Although 3,4-methylenedioxymethamphetamine (MDMA or ecstasy) has been shown to damage brain serotonin (5-HT) neurons in animals and possibly humans, little is known about the long-term consequences of MDMA-induced 5-HT neurotoxic lesions on functions in which 5-HT is involved, such as cognitive function. Because 5-HT transporters play a key element in the regulation of synaptic 5-HT transmission it may be important to control for the potential covariance effect of a polymorphism in the 5-HT transporter promoter gene region (5-HTTLPR) when studying the effects of MDMA as well as cognitive functioning. The aim of the study was to investigate the effects of moderate and heavy MDMA use on cognitive function, as well as the effects of long-term abstention from MDMA, in subjects genotyped for 5-HTTLPR. A second aim of the study was to determine whether these effects differ for females and males. Fifteen moderate MDMA users (<55 lifetime tablets), 22 heavy MDMA+ users (>55 lifetime tablets), 16 ex-MDMA+ users (last tablet > 1 year ago) and 13 controls were compared on a battery of neuropsychological tests. DNA from peripheral nuclear blood cells was genotyped for 5-HTTLPR using standard polymerase chain reaction methods.A significant group effect was observed only on memory function tasks (p = 0.04) but not on reaction times (p = 0.61) or attention/executive functioning (p = 0.59). Heavy and ex-MDMA+ users performed significantly poorer on memory tasks than controls. In contrast, no evidence of memory impairment was observed in moderate MDMA users. No significant effect of 5-HTTLPR or gender was observed. While the use of MDMA in quantities that may be considered "moderate" is not associated with impaired memory functioning, heavy use of MDMA use may lead to long lasting memory impairments. No effect of 5-HTTLPR or gender on memory function or MDMA use was observed.

From "Male Bonding Rituals" to "Suicide Tuesday": A qualitative study of issues faced by gay male ecstasy (MDMA) users

Use of MDMA and other club drugs has increased among gay men, but questions remain concerning the use, context, and popularity of these drugs; and views of their side effects. We interviewed in-depth 12 gay MDMA users in New York. MDMA had specific appeals to gay men, who often described isolation and stigmatization. Users underwent a period of initiation and social networks often became comprised of greater numbers of other users. Club environments fostered drug use and vice versa. Awareness of potential adverse effects varied and was minimized. Appropriate educational and prevention programs are needed to address these issues, and must take into account the specific contexts of these gay men's lives.

Selective impairment of sadness and disgust recognition in abstinent ecstasy users

Previous data have suggested that ecstasy use may affect cognitive functions. The relationship between ecstasy use and emotion recognition remains largely unknown. This study reports the findings on the neuropsychological effects of ecstasy use on recognition of basic human emotions among 100 abstinent ecstasy users, along with 100 demographically matched nonusers. Recognition of both facial and prosodic emotions was studied. In addition, neuropsychological predictors of emotion recognition for abstinent ecstasy users were examined. The results showed that abstinent ecstasy users were impaired, relative to nonusers, on overall emotion recognition. In particular, recognition of sadness and disgust was significantly affected. The emotion-recognition deficits observed among the abstinent ecstasy users may reflect a complex derangement of monoamines and/or general degenerative change observed in the addicted populations. The length of time in months since ecstasy was last consumed, cumulative ecstasy dosage, and years of education negatively predicted various domains of emotion recognition. The observation that nonverbal and verbal fluency functions were significant predictors of emotion identification, as well as of recognition of sadness and disgust, suggests that the frontal executive system might be affected by ecstasy use.

Quantitative PET studies of the serotonin transporter in MDMA users and controls using [11C]McN5652 and [11C]DASB

(+/-)3,4-Methylenedioxymethamphetamine (MDMA, 'Ecstasy') is a widely used illicit drug that produces toxic effects on brain serotonin axons and axon terminals in animals. The results of clinical studies addressing MDMA's serotonin neurotoxic potential in humans have been inconclusive. In the present study, 23 abstinent MDMA users and 19 non-MDMA controls underwent quantitative positron emission tomography (PET) studies using [11C]McN5652 and [11C]DASB, first- and second-generation serotonin transporter (SERT) ligands previously validated in baboons for detecting MDMA-induced brain serotonin neurotoxicity. Global and regional distribution volumes (DVs) and two additional SERT-binding parameters (DV(spec) and DVR) were compared in the two subject populations using parametric statistical analyses. Data from PET studies revealed excellent correlations between the various binding parameters of [11C]McN5652 and [11C]DASB, both in individual brain regions and individual subjects. Global SERT reductions were found in MDMA users with both PET ligands, using all three of the above-mentioned SERT-binding parameters. Preplanned comparisons in 15 regions of interest demonstrated reductions in selected cortical and subcortical structures. Exploratory correlational analyses suggested that SERT measures recover with time, and that loss of the SERT is directly associated with MDMA use intensity. These quantitative PET data, obtained using validated first- and second-generation SERT PET ligands, provide strong evidence of reduced SERT density in some recreational MDMA users.

Long-term effects of MDMA (Ecstasy) on the human central nervous system revealed by visual evoked potentials

Several studies indicate long-term cognitive impairment of MDMA (ecstasy) users. In the present study we attempted to establish whether electrophysiological correlates of low-level cognitive processes present a long-term alteration, dependent on the level of use of ecstasy. We addressed this issue by investigating amplitude and latency of VEPs related to a very simple discrimination task involving sustained attention (arousal). Eight heavy-MDMA users, eight moderate-MDMA users and 18 drug-free control subjects were asked to discriminate whether the digit at the centre of the screen was 1 or 2. None of the subjects (except one) had used MDMA in the 6 months previous testing. We measured psychophysical performance and EEG, recorded in Oz and Fz during task execution. The heavy-MDMA users made significantly more errors than the other two groups (p < .05). Moreover, they presented reduced amplitude but not latency of VEPs in both Oz and Fz. The effect in Oz is present in P200 (for heavy users only, p < .05) and in P300 components (for both MDMA groups; heavy users: p < .001, moderate users: p < .0.5). In Fz, the amplitude effect is present in N250 (for heavy users only, p < .05) and in P300 components (for both MDMA groups; heavy users: p < .05, moderate users: p < .05). The three groups do not differ in early components, reflecting low-level processing. These results provide evidence of long-term electrophysiological abnormality displayed by ecstasy users and agree with the suggestion that even typical recreational doses of ecstasy are sufficient to cause long-term altered cortical activity in humans.

Effect of ecstasy use on neuropsychological function: a study in Hong Kong

RATIONALE

Previous studies on the effects of ecstasy on neuropsychological performance have often recruited small sample sizes.

OBJECTIVES

The present study was conducted to validate previous findings regarding the effects of ecstasy consumption on neuropsychological performance.

METHOD

A comprehensive neuropsychological investigation was conducted in 100 abstinent ecstasy users and 100 matched non-user counterparts on standardized measures of working memory, verbal and non-verbal memory, verbal and figural fluency, and selective and switching attention.

RESULTS

Abstinent ecstasy users were impaired on verbal and non-verbal memory, complex attention, and verbal fluency, but not on working memory, relative to their non-user counterparts. Of particular interest was the fact that abstinent ecstasy users performed better on figural fluency relative to their non-user counterparts. In addition, only cumulative ecstasy consumption correlated with neuropsychological performances among abstinent ecstasy users. Canonical discriminant analysis yielded verbal and visual memory, switching attention, and verbal fluency as potential core neuropsychological variables for differentiating abstinent ecstasy users from non-users. Levels of depression and general non-verbal intelligence, as measured by the Beck Depression Inventory and the test of non-verbal Intelligence, respectively, were not likely to affect these findings, since these measures were matched between ecstasy users and non-users.

CONCLUSIONS

These findings suggest that previous ecstasy consumption can affect a wide range of neuropsychological performance, though figural fluency may be subsequently enhanced as a result of the phenomenon of "cortical disinhibition." Furthermore, measures of verbal and visual memory, switching attention, and verbal fluency may be particularly useful for differentiating abstinent ecstasy users from non-users.

3,4-Methylenedioxymethamphetamine and naloxone in rat rotational behaviour and open field

It has recently been shown that 3,4-Methylenedioxymethamphetamine (MDMA) has an anti-parkinsonian effect in rodent models of Parkinson's disease. The mechanism of this anti-parkinsonian action is unknown. Opioids have been suggested to play a role in MDMA-induced behaviour. We therefore investigated MDMA and naloxone in the rat rotational behavioural model. Male Sprague-Dawley rats were lesioned unilaterally with 6-hydroxydopamine at the medial forebrain bundle. Administration of R/S-MDMA (5 mg/kg, s.c.) produced ipsilateral rotations. Naloxone (2, 5, 10 mg/kg, s.c.) did not produce rotations on its own but reduced the number of MDMA-induced ipsilateral rotations. This effect was not dose-dependent. In contrast to reports on mice, in unlesioned animals, naloxone (10 mg/kg, s.c.) did not block MDMA (5 mg/kg, s.c.)-induced hyperactivity in an open field in our experiment. It is concluded that endogenous opioids play a role in MDMA's action in the rat rotational behavioural model.

Rat brain serotonin neurones that express neuronal nitric oxide synthase have increased sensitivity to the substituted amphetamine serotonin toxins 3,4-methylenedioxymethamphetamine and p-chloroamphetamine

Substituted amphetamines such as p-chloroamphetamine and the abused drug methylenedioxymethamphetamine cause selective destruction of serotonin axons in rats, by unknown mechanisms. Since some serotonin neurones also express neuronal nitric oxide synthase, which has been implicated in neurotoxicity, the present study was undertaken to determine whether nitric oxide synthase expressing serotonin neurones are selectively vulnerable to methylenedioxymethamphetamine or p-chloroamphetamine. Using double-labeling immunocytochemistry and double in situ hybridization for nitric oxide synthase and the serotonin transporter, it was confirmed that about two thirds of serotonergic cell bodies in the dorsal raphé nucleus expressed nitric oxide synthase, however few if any serotonin transporter immunoreactive axons in striatum expressed nitric oxide synthase at detectable levels. Methylenedioxymethamphetamine (30 mg/kg) or p-chloroamphetamine (2 x 10 mg/kg) was administered to Sprague-Dawley rats, and 7 days after drug administration there were modest decreases in the levels of serotonin transporter protein in frontal cortex, and striatum using Western blotting, even though axonal loss could be clearly seen by immunostaining. p-Chloroamphetamine or methylenedioxymethamphetamine administration did not alter the level of nitric oxide synthase in striatum or frontal cortex, determined by Western blotting. Analysis of serotonin neuronal cell bodies 7 days after p-chloroamphetamine treatment, revealed a net down-regulation of serotonin transporter mRNA levels, and a profound change in expression of nitric oxide synthase, with 33% of serotonin transporter mRNA positive cells containing nitric oxide synthase mRNA, compared with 65% in control animals. Altogether these results support the hypothesis that serotonin neurones which express nitric oxide synthase are most vulnerable to substituted amphetamine toxicity, supporting the concept that the selective vulnerability of serotonin neurones has a molecular basis.

Impaired executive function in male MDMA ("ecstasy") users

RATIONALE

Long-term users of ecstasy have shown impaired performance on a multitude of cognitive abilities (most notably memory, attention, executive function). Research into the pattern of MDMA effects on executive functions remains fragmented, however.

OBJECTIVES

To determine more systematically what aspects of executive function are affected by a history of MDMA use, by using a model that divides executive functions into cognitive flexibility, information updating and monitoring, and inhibition of pre-potent responses.

METHODS

MDMA users and controls who abstained from ecstasy and other substances for at least 2 weeks were tested with a computerized cognitive test battery to assess their abilities on tasks that measure the three submodalities of executive function, and their combined contribution on two more complex executive tasks. Because of sex-differential effects of MDMA reported in the literature, data from males and females were analyzed separately.

RESULTS

Male MDMA users performed significantly worse on the tasks that tap on cognitive flexibility and on the combined executive function tasks; no differences were found on the other cognitive tasks. Female users showed no impairments on any of the tasks.

CONCLUSIONS

The present data suggest that a history of MDMA use selectively impairs executive function. In male users, cognitive flexibility was impaired and increased perseverative behavior was observed. The inability to adjust behavior rapidly and flexibly may have repercussions for daily life activities.

Clinical pharmacokinetics of amfetamine and related substances: monitoring in conventional and non-conventional matrices

Consumption of amfetamine-type stimulants, including classical amfetamines and 'designer drugs', has been recognised as one of the most significant trends in drug abuse at the end of the past century and at the beginning of the current one. The first cause is the increasing consumption amongst youth of methylenedioxy- and methoxy-substituted amfetamines, of which the pharmacology in humans is currently under investigation. Secondly, the abuse of more classical amfetamines, such as amfetamine itself and metamfetamine, continues to be highly prevalent in some geographical regions. Amfetamines are powerful psychostimulants, producing increased alertness, wakefulness, insomnia, energy and self-confidence in association with decreased fatigue and appetite as well as enhanced mood, well-being and euphoria. From a clinical pharmacokinetic perspective, amfetamine-type stimulants are rather homogeneous. Their oral bioavailability is good, with a high distribution volume (4 L/kg) and low binding to plasma proteins (less than 20%). The elimination half-life is 6-12 hours. Both hepatic and renal clearance contribute to their elimination from the body. Hepatic metabolism is extensive in most cases, but a significant percentage of the drug always remains unaltered. Amfetamine and related compounds are weak bases, with a pKa around 9.9, and a relatively low molecular weight. These characteristics allow amfetamine-type stimulants to diffuse easily across cell membranes and lipid layers and to those tissues or biological substrates with a more acidic pH than blood, facilitating their detection in alternative matrices at relatively high concentrations. In most cases, the concentrations found are higher than expected from the Henderson-Hasselbach equation. Drug monitoring in non-conventional biological matrices (e.g. saliva, hair, nails, sweat) has recently gained much attention because of its possible applications in clinical and forensic toxicology. An individual's past history of medication, compliance or drug abuse can be obtained from testing of hair and nails, whereas data on current status of drug use can be provided by analysis of sweat and saliva. Because of the physicochemical properties of amfetamine-type stimulants, this group of drugs is one of the most suitable for drug testing in non-conventional matrices.

Serotonin neurotoxins--past and present

Autoxidation pathways and redox reactions of dihydroxytryptamines (5,6- and 5,7-DHT) and of 6-hydroxydopamine (6-OH-DA) are illustrated, and their potential role in aminergic neurotoxicity is discussed. It is proposed that certain aspects of the cytotoxicity of 6-OH-DA and of the DHTs, namely redox cycling of their quinone- and quinoneimine-intermediates as a source of free radicals, may also apply to quinoidal reactive intermediates and to glutathionyl- or cysteinyl conjugates ("thioether adducts") of o-dihydroxylated (catechol-like) metabolites of certain substituted amphetamines (of methylenedioxymethamphetamine (MDMA) and of methylenedioxyamphetamine (MDA)). Despite similarities in their primary interaction with the plasmalemmal (serotonergic transporter/dopamine transporter, SERT/DAT) and vesicular monoamine transporters (VMAT2), MDMA and fenfluramine (N-ethyl-meta-trifluoromethamphetamine, Fen) differ substantially in many aspects of their metabolism, pharmacokinetics, pharmacology, and neurotoxicology profile; the consequences of these differences for neuronal response patterns and long-term survival prospects are not yet fully understood. However, sustained hyperthermia appears to be a critical factor in these differences. Methodological requirements for adequate detection and description of pre- and postsynaptic forms of drug-induced neurotoxicity are exemplified using recently published accounts. The inclusion of microglial markers into research strategies has widened contemporary pathogenetic concepts on methamphetamine (MA)-induced neurotoxicity as an example of inflammatory neurodegeneration, thus complementing the traditional ROS and RNS-dependent stress models. Amphetamine-type neurotoxicity studies may assist in elaborating of preventive strategies for human neurodegenerative disorders.

The pharmacology and clinical pharmacology of 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy")

The amphetamine derivative (+/-)-3,4-methylenedioxymethamphetamine (MDMA, ecstasy) is a popular recreational drug among young people, particularly those involved in the dance culture. MDMA produces an acute, rapid enhancement in the release of both serotonin (5-HT) and dopamine from nerve endings in the brains of experimental animals. It produces increased locomotor activity and the serotonin behavioral syndrome in rats. Crucially, it produces dose-dependent hyperthermia that is potentially fatal in rodents, primates, and humans. Some recovery of 5-HT stores can be seen within 24 h of MDMA administration. However, cerebral 5-HT concentrations then decline due to specific neurotoxic damage to 5-HT nerve endings in the forebrain. This neurodegeneration, which has been demonstrated both biochemically and histologically, lasts for months in rats and years in primates. In general, other neurotransmitters appear unaffected. In contrast, MDMA produces a selective long-term loss of dopamine nerve endings in mice. Studies on the mechanisms involved in the neurotoxicity in both rats and mice implicate the formation of tissue-damaging free radicals. Increased free radical formation may result from the further breakdown of MDMA metabolic products. Evidence for the occurrence of MDMA-induced neurotoxic damage in human users remains equivocal, although some biochemical and functional data suggest that damage may occur in the brains of heavy users. There is also some evidence for long-term physiological and psychological changes occurring in human recreational users. However, such evidence is complicated by the lack of knowledge of doses ingested and the fact that many subjects studied are or have been poly-drug users.

Demonstration and localization of neuronal degeneration in the rat forebrain following a single exposure to MDMA

Methylenedioxymethamphetamine (MDMA, Ecstasy) is a powerful releaser of serotonin. Increasing recreational use of this stimulant and hallucinogenic drug has raised concerns about its potential to produce brain damage. The vast majority of previous research studies have focused on the compound's ability to deplete serotonin (5-hydroxytryptamine, 5-HT) from axon terminals. Despite extensive research on this '5-HT terminal neurotoxicity', a much less studied aspect of MDMA toxicity involves its ability to actually kill nerve cells. Only two prior studies mention the existence of MDMA-induced neuronal degeneration, as reflected by a limited number of argyrophylic neurons within the somatosensory cortex, following very high doses of MDMA. The development of Fluoro-Jade B as a simple and reliable marker of neuronal degeneration has allowed us to conduct the first comprehensive localization of MDMA induced neuronal degeneration throughout the entire rat forebrain. In addition to the previously reported neuronal degeneration within parietal cortex, degenerating neurons were also observed in the insular/perirhinal cortex, the ventromedial/ventrolateral thalamus, and the tenia tecta. The extent of neuronal degeneration observed generally correlated with the degree of hyperthermia achieved.

Methylenedioxymethamphetamine (MDMA, Ecstasy) neurotoxicity: cellular and molecular mechanisms

Methylenedioxymethamphetamine (MDMA, Ecstasy) is a very popular drug of abuse. This has led to new intense concerns relevant to its nefarious neuropsychiatric effects. These adverse events might be related to the neurotoxic effects of the drug. Although the mechanisms of MDMA-induced neurotoxicity remain to be fully characterized, exposure to the drug can cause acute and long-term neurotoxic effects in animals and nonhuman primates. Recent studies have also documented possible toxic effects in the developing fetus. Nevertheless, there is still much debate concerning the effects of the drug in humans and how to best extrapolate animal and nonhuman primate data to the human condition. Herein, we review the evidence documenting the adverse effects of the drug in some animal models. We also discuss possible mechanisms for the development of MDMA neurotoxicity. Data supporting deleterious effects of this drug on the developing fetus are also described. Much remains to be done in order to clarify the molecular and biochemical pathways involved in the long-term neuroplastic changes associated with MDMA abuse.

Designer drugs: how dangerous are they?

Of the designer drugs, the amphetamine analogues are the most popular and extensively studied, ecstasy (3,4-methylenedioxymethamphetamine; MDMA) in particular. They are used recreationally with increasing popularity despite animal studies showing neurotoxic effects to serotonin (5-HT) and/or dopamine (DA) neurones. However, few detailed assessments of risks of these drugs exist in humans. Previously, there were no methods available for directly evaluating the neurotoxic effects of amphetamine analogues in the living human brain. However, development of in vivo neuroimaging tools have begun to provide insights into the effects of MDMA in human brain. In this review, contributions of brain imaging studies on the potential 5-HT and/or DA neurotoxic effects of amphetamine analogues will be highlighted in order to delineate the risks these drugs engender in humans, focusing on MDMA. An overview will be given of PET, SPECT and MR Spectroscopy studies employed in human users of these drugs. Most of these studies provide suggestive evidence that MDMA is neurotoxic to 5-HT neurones, and (meth)amphetamine to DA neurones in humans. These effects seem to be dose-related, leading to functional impairments such as memory loss, and are reversible in several brain regions. However most studies have had a retrospective design, in which evidence is indirect and differs in the degree to which any causative links can be implied between drug use and neurotoxicity. Therefore, at this moment, it cannot be ascertained that humans are susceptible to MDMA-induced 5-HT injury or (meth)amphetamine-induced DA injury. Finally, although little is known about other amphetamine analogues there are important questions as to the safety of these designer drugs as well, in view of the fact that they are chemically closely related to MDMA and some have been shown to be 5-HT neurotoxins in animals.

Validity of [123I]beta-CIT SPECT in detecting MDMA-induced serotonergic neurotoxicity

Recent [123I]beta-CIT single-photon emission computed tomography (SPECT) studies revealed decreased serotonin transporters (SERT) density in the brain of humans with a history of MDMA ("Ecstasy") use. However, [123I]beta-CIT SPECT has until now not been validated as a method for detecting such serotonergic lesions. Therefore, the present study was undertaken. Following baseline [123I]beta-CIT SPECT scans, a rhesus monkey was treated with MDMA (5 mg/kg, s.c. twice daily for 4 consecutive days). SPECT studies 4, 10, and 31 days after MDMA treatment revealed decreases in [123I]beta-CIT binding ratios in the SERT-rich brain region studied (hypothalamic/midbrain region), with SERT density reduced by 39% in this brain region 31 days after treatment. Data obtained with SPECT studies correlated well with SERT density determined with autoradiography after sacrifice of the animal (-34%). In addition, ex vivo [123I]beta-CIT binding studies in rats 1 week after treatment with neurotoxic doses of MDMA (20 mg/kg s.c. twice daily for 4 consecutive days) revealed significant reductions in [123I]beta-CIT binding in SERT-rich regions (including the hypothalamus) when compared to saline-treated rats. The combined results of these studies indicate that SPECT imaging of SERT with [123I]beta-CIT can detect changes in SERT density secondary to MDMA-induced neurotoxicity in the hypothalamic/midbrain region, and possibly other brain regions.

Studies, using in vivo microdialysis, on the effect of the dopamine uptake inhibitor GBR 12909 on 3,4-methylenedioxymethamphetamine ('ecstasy')-induced dopamine release and free radical formation in the mouse striatum

The present study examined the mechanisms by which 3,4-methylenedioxymethamphetamine (MDMA) produces long-term neurotoxicity of striatal dopamine neurones in mice and the protective action of the dopamine uptake inhibitor GBR 12909. MDMA (30 mg/kg, i.p.), given three times at 3-h intervals, produced a rapid increase in striatal dopamine release measured by in vivo microdialysis (maximum increase to 380 +/- 64% of baseline). This increase was enhanced to 576 +/- 109% of baseline by GBR 12909 (10 mg/kg, i.p.) administered 30 min before each dose of MDMA, supporting the contention that MDMA enters the terminal by diffusion and not via the dopamine uptake site. This, in addition to the fact that perfusion of the probe with a low Ca(2+) medium inhibited the MDMA-induced increase in extracellular dopamine, indicates that the neurotransmitter may be released by a Ca(2+) -dependent mechanism not related to the dopamine transporter. MDMA (30 mg/kg x 3) increased the formation of 2,3-dihydroxybenzoic acid (2,3-DHBA) from salicylic acid perfused through a probe implanted in the striatum, indicating that MDMA increased free radical formation. GBR 12909 pre-treatment attenuated the MDMA-induced increase in 2,3-DHBA formation by approximately 50%, but had no significant intrinsic radical trapping activity. MDMA administration increased lipid peroxidation in striatal synaptosomes, an effect reduced by approximately 60% by GBR 12909 pre-treatment. GBR 12909 did not modify the MDMA-induced changes in body temperature. These data suggest that MDMA-induced toxicity of dopamine neurones in mice results from free radical formation which in turn induces an oxidative stress process. The data also indicate that the free radical formation is probably not associated with the MDMA-induced dopamine release and that MDMA does not induce dopamine release via an action at the dopamine transporter.

Recreational Ecstasy/MDMA, the serotonin syndrome, and serotonergic neurotoxicity

The ring-substituted amphetamine derivative 3,4-methylenedioxymethamphetamine (MDMA) or "Ecstasy" is widely used a recreational drug. It stimulates the release and inhibits the reuptake of serotonin (5-HT) and other neurotransmitters such as dopamine to a lesser extent. The acute boost in monoamine activity can generate feelings of elation, emotional closeness, and sensory pleasure. In the hot and crowded conditions of raves/dances, mild versions of the serotonin syndrome often develop, when hyperthermia, mental confusion, and hyperkinesia predominate. Rest in a cooler environment generally reverses these problems, although they can develop into medical emergencies, which occasionally prove fatal. This acute serotonergic overactivity is exacerbated by the high ambient temperatures, overcrowding (aggregate toxicity), and use of other stimulant drugs. The on-drug experience is generally followed by negative moods, with 80--90% of weekend Ecstasy users reporting 'midweek blues', due probably to monoaminergic depletion. Single doses of MDMA can cause serotonergic nerve damage in laboratory animals, with repeated doses causing extensive loss of distal axon terminals. Huether's explanatory model for this 5-HT neurotoxicity will be briefly described. There is an increasing body of evidence for equivalent neuropsychobiological damage in humans. Abstinent regular Ecstasy users often show: reduced cerebrospinal 5-HIAA, reduced density of 5-HT transporters, blunted response to a fenfluramine challenge, memory problems, higher cognitive deficits, various psychiatric disorders, altered appetite, and loss of sexual interest. Functional deficits may remain long after drug use has ceased and are consistent with serotonergic axonal loss in higher brain regions.

MDMA ('ecstasy') use, and its association with high risk behaviors, mental health, and other factors among gay/bisexual men in New York City

This study assesses patterns of use of methylenedioxymethamphetamine (MDMA or 'ecstasy'), and the characteristics of users, in a sample of 733 men who have sex with men (MSM) in New York City. Among respondents, 13.7% reported using MDMA in the past 6 months, with mean frequency of use of 6.24 times in that period. MDMA users were found to be younger, less educated, to have had more male partners, more one night stands with men, more visits to bars or clubs and sex clubs or bathhouses, to have unprotected anal sex with a male, to be likely to have been the victim of physical domestic violence, to have more gay/bisexual friends, to have disclosed their sexual orientation to more friends, family members, and coworkers, and to have higher levels of gay community participation and affiliation. Among MDMA users, higher frequency of MDMA use was associated with being younger, having more visits to bars or clubs, more gay/bisexual friends, and having an HIV negative test result or never having been tested. MDMA users thus constitute a group at risk for sexually transmitted diseases, including HIV, and other problems. The data suggest that MDMA use is associated with being more 'out', which may be advantageous in helping gay men deal with harmful psychological effects of stigma, but may place individuals in settings that expose them to MDMA. These men have also presumably already been well exposed to safer sex messages within the gay community, thus raising challenges for interventions aimed at prevention, as well as opportunities (e.g. MSM and community specific interventions) that need to be further explored.