Orally administered MDMA causes a long-term depletion of serotonin in rat brain

Recent studies suggest that 3,4-methylenedioxymethylamphetamine (MDMA), when administered subcutaneously, is toxic to central serotonergic neurons in rats. Because humans typically self-administer this drug orally, we compared this route to the s.c. route of administration. Orally administered MDMA produced a dose-related depletion of serotonin comparable to that produced by the s.c. route. These findings suggest that MDMA, when given orally, retains it neurotoxic activity and that humans using MDMA may be at risk for developing a persistent depletion of brain serotonin.     

5-Hydroxyindoleacetic acid in cerebrospinal fluid reflects serotonergic damage induced by 3,4-methylenedioxymethamphetamine in CNS of non-human primates

This study examined whether 5-hydroxyindoleacetic acid (5-HIAA) in cerebrospinal fluid (CSF) could be used to detect serotonergic damage induced by (+/-)-3,4-methylenedioxymethamphetamine (MDMA) in the central nervous system (CNS) of non-human primates. Monkeys were administered toxic doses of MDMA; two weeks later, the animals were lightly anesthetized with ether and CSF was obtained by means of cervical puncture. Later that same day, the animals were killed for direct determination of CNS serotonin and 5-HIAA concentrations. Monkeys with 73-94% depletions of serotonin and 5-HIAA in brain and 42-45% depletions of serotonin and 5-HIAA in the spinal cord had a 60 +/- 7% reduction of 5-HIAA in CSF, without any change in homovanillic acid (HVA) or 3-methoxy-4-hydroxyphenethyleneglycol (MHPG). These findings indicate that CSF 5-HIAA can be employed to detect central serotonergic damage produced by MDMA in non-human primates, and suggest that CSF 5-HIAA may be useful for detecting MDMA-induced neuronal damage in humans.     

MDMA alters the response of the circadian clock to a photic and non-photic stimulus

3,4-Methylenedioxymethamphetamine (MDMA or 'Ecstasy') is a widely used recreational drug that damages serotonin 5-HT neurons in animals and possibly humans. Published literature has shown that the serotonergic system is involved in photic and non-photic phase shifting of the circadian clock, which is located in the suprachiasmatic nuclei. Despite the dense innervation of the circadian system by 5-HT and the known selective neurotoxicity of MDMA, little is known about the effects of MDMA on the circadian oscillator. This study investigated whether repeated exposure to the serotonin neurotoxin MDMA alters the behavioural response of the Syrian hamster to phase shift to the serotonin 5-HT1A/7 receptor agonist 8-hydroxy-2-(di-n-propylamino) tetralin hydrobromide (8-OH-DPAT). This agonist was administered under an Aschoff Type I (CT8) and Aschoff Type II (ZT8) paradigm (5 mg/kg) and was given before and after treatment with MDMA (10, 15 and 20 mg/kg administered on successive days). Pre-treatment with MDMA significantly attenuated phase shifts to 8-OH-DPAT. We also tested the ability of the clock to phase shift to a photic stimulus after treatment with MDMA. A 15-min light pulse (mean lux 125 at CT14 or ZT14) was administered before and after treatment with MDMA. Phase shifts to a photic stimulus were significantly attenuated by pre-treatment with MDMA. Our study demonstrates that repeated exposure to MDMA may alter the ability of the circadian clock to phase shift to a photic and non-photic stimulus in the hamster. Disruption of circadian function has been linked with a variety of clinical conditions such as sleep disorders, mood, concentration difficulties and depression, consequently outlining the potential dangers of long-term ecstasy use.     

Long-term neuropsychiatric consequences of "ecstasy" (MDMA): a review

The recreational drug "ecstasy" (3,4-methylenedioxymethamphetamine, or MDMA) is widely used by young people throughout the world. Experimental studies indicate that MDMA damages serotonergic neurons in animals and possibly in humans. Repeated use may induce long-term neurotoxic effects, with cognitive and behavioral implications. We reviewed both the preclinical and the clinical literature to assess the evidence for persistent neuropsychiatric sequelae in humans. We focused on studies of chronic recreational use and reports of presence or absence of neurological, psychiatric, and psychological problems related to MDMA exposure. These investigations show repeated use of ecstasy to be associated with sleep, mood, and anxiety disturbances, elevated impulsiveness, memory deficits, and attention problems, which may persist for up to 2 years after cessation. In a subset of humans, particularly adolescents, depletion of serotonin by MDMA use may hasten or enhance vulnerability to a wide array of neuropsychiatric problems. Together, the studies reviewed provide substantial evidence that MDMA causes neuronal damage in animals and humans. Additional research is necessary to determine whether the MDMA-induced destruction of serotonergic neurons can have long-term and possibly permanent neuropsychiatric consequences in humans.     

Effect of ecstasy [3,4-methylenedioxymethamphetamine (MDMA)] on cerebral blood flow: a co-registered SPECT and MRI study

3,4-methylenedioxymethamphetamine (MDMA), an illicit recreational drug, damages serotonergic nerve endings. Since the cerebrovasculature is regulated partly by the serotonergic system, MDMA may affect cerebral blood flow (CBF) in humans. We evaluated 21 abstinent recreational MDMA users and 21 age- and gender-matched healthy subjects with brain SPECT and MRI. Ten of the MDMA subjects also had repeat SPECT and MRI after receiving two doses of MDMA. Abstinent MDMA users showed no significantly different global or regional CBF (rCBF) compared to the control subjects. However, within 3 weeks after MDMA administration, rCBF remained decreased in the visual cortex, the caudate, the superior parietal and dorsolateral frontal regions compared to baseline rCBF. The decreased rCBF tended to be more pronounced in subjects who received the higher dosage of MDMA. Two subjects who were scanned at 2-3 months after MDMA administration showed increased rather than decreased rCBF. Low-dose recreational MDMA use does not cause detectable persistent rCBF changes in humans. The lack of long-term rCBF changes may be due to a non-significant effect of serotonergic deficits on rCBF, or regeneration of serotonergic nerve terminals. The subacute decrease in rCBF after MDMA administration may be due to the direct effect of MDMA on the serotonergic system or the indirect effects of its metabolites on the dopaminergic system; the preliminary data suggest these effects may be transient.     

Effects of MDMA ('ecstasy') on firing rates of serotonergic, dopaminergic, and noradrenergic neurons in the rat

3,4-Methylenedioxymethamphetamine (MDMA), a non-hallucinogenic drug of abuse, potently depressed firing rates of a subpopulation of serotonin neurons in the dorsal and median raphe. High neurotoxic doses depressed those serotonin neurons unresponsive to low doses. Noradrenaline neurons in the locus coeruleus were also depressed by moderate doses. Dopamine neurons were unaffected. It is concluded that MDMA's unique psychological effects are mediated through a subpopulation of serotonergic and noradrenergic neurons, presumably through effects on release mechanisms.     

Experimental studies on 3,4-methylenedioxymethamphetamine (MDMA, “ECSTASY”) and its potential to damage brain serotonin neurons

A number of drugs that fall into the broad category of “ring-substituted amphetamines” have been found to be neurotoxic toward brain monoamine neurons in animals. Several of these drugs, including (3,4-methylenedioxymethamphetamine (MDMA, “Ecstasy”) and methamphetamine (“speed”) and fenfluramine (“Pondimin”) have been used or abused by humans. A growing body of evidence indicates that humans, like animals, are susceptible to substituted amphetamine-induced neurotoxic injury, and that consequences of this injury can be subtle. This article will review the effects of ring-substituted amphetamine analogs on brain monoamine neurons, using MDMA as the prototype. Studies documenting MDMA neurotoxic potential toward brain serotonin (5-HT) neurons in animals are summarized first. Human MDMA studies are then discussed, beginning with a consideration of methodological challenges in evaluating the status of 5-HT neurons in the living human brain. Recent findings indicating possible functional alterations in brain serotonergic systems in humans with a history of extensive MDMA exposure are then presented, including some new findings on sleep and personality in abstinent MDMA users.     

α-Methyltyrosine blocks methylamphetamine-induced degeneration in the rat somatosensory cortex

Neurochemical and histological studies suggest that methylamphetamine (MA) administered continously or in high doses is toxic to dopaminergic and serotonergic nerve terminals. Degeneration of the dopaminergic or serotonergic cell bodies themselves has not been reported, however. In the present study, administration of a single 100 mg/kg dose of MA was toxic to a subpopulation of neurons in the somatosensory cortex, an area of the brain which does not contain catecholaminergic or serotonergic cell bodies. This dose of MA also produced a long-lasting depletion of serotonin (5-HT) but not norepinephine in the somatosensory cortex. Dompamine levels in the somatosensory cortices of control animals were virtually undetectable and therefore were not studied further. Administation of α-methyltyrosine (α-MT), a catecholamine synthesis inhibitor, prior to the injection of MA blocked both the depletion of 5-HT and the degeneration of cortical perikarya produced by MA alone. Since the MA-induced depletion of 5-HT and the MA-induced degeneration of cortical perikarya are correlated, we suggest that the serotonergic system may be involved in the toxic effects of MA on the cortical neurons.     

alpha-Methyltyrosine blocks methylamphetamine-induced degeneration in the rat somatosensory cortex

Neurochemical and histological studies suggest that methylamphetamine (MA) administered continuously or in high doses is toxic to dopaminergic and serotonergic nerve terminals. Degeneration of the dopaminergic or serotonergic cell bodies themselves has not been reported, however. In the present study, administration of a single 100 mg/kg dose of MA was toxic to a subpopulation of neurons in the somatosensory cortex, an area of the brain which does not contain catecholaminergic or serotonergic cell bodies. This dose of MA also produced a long-lasting depletion of serotonin (5-HT) but not norepinephrine in the somatosensory cortex. Dopamine levels in the somatosensory cortices of control animals were virtually undetectable and therefore were not studied further. Administration of alpha-methyltyrosine (alpha-MT), a catecholamine synthesis inhibitor, prior to the injection of MA blocked both the depletion of 5-HT and the degeneration of cortical perikarya produced by MA alone. Since the MA-induced depletion of 5-HT and the MA-induced degeneration of cortical perikarya are correlated, we suggest that the serotonergic system may be involved in the toxic effects of MA on the cortical neurons.     

Influence of PCPA and MDMA (ecstasy) on physiology, development and behavior in Drosophila melanogaster

The effects of para-chlorophenylalanine (PCPA) and 3,4 methylenedioxy-methamphetamine (MDMA, 'ecstasy') were investigated in relation to development, behavior and physiology in larval Drosophila. PCPA blocks the synthesis of serotonin (5-HT) and MDMA is known to deplete 5-HT in mammalian neurons; thus these studies were conducted primarily to target the serotonergic system. Treatment with PCPA and MDMA delayed time to pupation and eclosion. The developmental rate was investigated with a survival analysis statistical approach that is unique for Drosophila studies. Locomotion and eating were reduced in animals exposed to MDMA or PCPA. Sensitivity to exogenously applied 5-HT on an evoked sensory-central nervous system (CNS)-motor circuit showed that the CNS is sensitive to 5-HT but that when depleted of 5-HT by PCPA a decreased sensitivity occurred. A diet with MDMA produced an enhanced response to exogenous 5-HT on the central circuit. Larvae eating MDMA from the first to third instar did not show a reduction in 5-HT within the CNS; however, eating PCPA reduced 5-HT as well as dopamine content as measured by high performance liquid chromatography from larval brains. As the heart serves as a good bioindex of 5-HT exposure, it was used in larvae fed PCPA and MDMA but no significant effects occurred with exogenous 5-HT. In summary, the action of these pharmacological compounds altered larval behaviors and development. PCPA treatment changed the sensitivity in the CNS to 5-HT, suggesting that 5-HT receptor regulation is modulated by neural activity of the serotonergic neurons. The actions of acute MDMA exposure suggest a 5-HT agonist action or possible dumping of 5-HT from neurons.     

Damage of serotonergic axons and immunolocalization of Hsp27, Hsp72, and Hsp90 molecular chaperones after a single dose of MDMA administration in Dark Agouti rat: temporal, spatial, and cellular patterns

3,4-Methylenedioxymethamphetamine (MDMA, "ecstasy") causes long-term disturbance of the serotonergic system. We examined the temporal, spatial, and cellular distribution of three molecular chaperones, Hsp27, Hsp72, and Hsp90, 3 and 7 days after treatment with 7.5, 15, and 30 mg/kg single intraperitoneal (i.p.) doses of MDMA in Dark Agouti rat brains. Furthermore, we compared the immunostaining patterns of molecular chaperones with serotonergic axonal-vulnerability evaluated by tryptophan-hydroxylase (TryOH) immunoreactivity and with astroglial-activation detected by GFAP-immunostaining. There was a marked reduction in TryOH-immunoreactive axon density after MDMA treatment in all examined areas at both time points. Three days after treatment, a significant dose-dependent increase in Hsp27-immunoreactive protoplasmic astrocytes was found in the cingulate, frontal, occipital, and pyriform cortex, and in the hippocampus CA1. However, there was no increase in astroglial Hsp27-immunoreactivity in the caudate putamen, lateral septal nucleus, or anterior hypothalamus. A significant increase in the GFAP immunostaining density of protoplasmic astrocytes was found only in the hippocampus CA1. In addition, numerous strong Hsp72-immunopositive neurons were found in some brain areas only 3 days after treatment with 30 mg/kg MDMA. Increased Hsp27-immunoreactivity exclusively in the examined cortical areas reveals that Hsp27 is a sensitive marker of astroglial response to the effects of MDMA in these regions of Dark Agouti rat brain and suggests differential responses in astroglial Hsp27-expression between distinct brain areas. The co-occurrence of Hsp27 and GFAP response exclusively in the hippocampus CA1 may suggest the particular vulnerability of this region. The presence of strong Hsp72-immunopositive neurons in certain brain areas may reflect additional effects of MDMA on nonserotonergic neurons.     

Neurotoxicity of drugs of abuse - the case of methylenedioxy amphetamines (MDMA,ecstasy ), and amphetamines

Ecstasy (MDMA, 3,4-methylendioxymethamphetamine) and the stimulants methamphetamine (METH, speed) and amphetamine are popular drugs among young people, particularly in the dance scene. When given in high doses both MDMA and the stimulant amphetamines are clearly neurotoxic in laboratory animals. MDMA causes selective and persistent lesions of central serotonergic nerve terminals, whereas amphetamines damage both the serotonergic and dopaminergic systems. In recent years, the question of ecstasy-induced neurotoxicity and possible functional sequelae has been addressed in several studies in drug users. Despite large methodological problems, the bulk of evidence suggests residual alterations of serotonergic transmission in MDMA users, although at least partial recovery may occur after long-term abstinence. However, functional sequelae may persist even after longer periods of abstinence. To date, the most consistent findings associate subtle cognitive impairments with ecstasy use, particularly with memory. In contrast, studies on possible long-term neurotoxic effects of stimulant use have been relatively scarce. Preliminary evidence suggests that alterations of the dopaminergic system may persist even after years of abstinence from METH, and may be associated with deficits in motor and cognitive performance. In this paper, we will review the literature focusing on human studies.     

Myelin staining of deep white matter in the dorsolateral prefrontal cortex in schizophrenia, bipolar disorder, and unipolar major depression

The recreational drug MDMA (3,4, methylenedioxymethamphetamine; sold under the street name of Ecstasy) is toxic to serotonergic axons in some animal models of MDMA administration. In humans, MDMA use is associated with alterations in markers of brain function that are pronounced in occipital cortex. Among neuroimaging methods, magnetic resonance spectroscopy (MRS) studies of brain metabolites N-acetylaspartate (NAA) and myoinositol (MI) at a field strength of 1.5 Tesla (T) reveal inconsistent results in MDMA users. Because higher field strength proton MRS has theoretical advantages over lower field strengths, we used proton MRS at 4.0 T to study absolute concentrations of occipital cortical NAA and MI in a cohort of moderate MDMA users (n=9) versus non-MDMA using (n=7) controls. Mean NAA in non-MDMA users was 10.47 mM (+/-2.51), versus 9.83 mM (+/-1.94) in MDMA users. Mean MI in non-MDMA users was 7.43 mM (+/-.68), versus 6.57 mM (+/-1.59) in MDMA users. There were no statistical differences in absolute metabolite levels for NAA and MI in occipital cortex of MDMA users and controls. These findings are not supportive of MDMA-induced alterations in NAA or MI levels in this small sample of moderate MDMA users. Limitations to this study suggest caution in the interpretation of these results.     

Neuroanatomic specificity and time course of alterations in rat brain serotonergic pathways induced by MDMA (3,4-methylenedioxymethamphetamine): assessment using quantitative autoradiography.

The widely abused "designer" drug MDMA (3,4-methylenedioxymethamphetamine) has been shown to cause marked and long-lasting changes in brain serotonergic systems. The present study uses quantitative in vitro autoradiography of 3H-paroxetine labeled 5-HT uptake sites to assess the time-dependent effects of MDMA on 5-HT neurons in specific neuroanatomic loci. Following treatment with MDMA (20 mg/kg, b.i.d. for 4 days), marked decreases in 5-HT uptake sites were observed in a number of brain regions known to receive projections of 5-HT neurons. These regions included cerebral cortex, caudate nucleus, hippocampus, nucleus accumbens, olfactory tubercle, superior and inferior colliculi, geniculate nuclei, and most thalamic nuclei. In contrast, other areas such as the septal nuclei and some thalamic nuclei which also receive 5-HT projections were not substantially affected by this drug. In most regions, decreases in 5-HT uptake sites occurred within 24 hours of the last dose of MDMA and persisted at the 2 week time point. Some regions such as dorsal striatum exhibited a time-dependent reduction with greater reductions occurring at 2 weeks rather than immediately following the MDMA treatment regimen. The density of 5-HT uptake sites in other regions such as endopiriform nucleus and substantia nigra at the 2 week versus 18 hour time point indicated some degree of region-specific recovery. Regions which demonstrated no significant reduction in 5-HT uptake sites included the dorsal and median raphe nuclei, ventral tegmental area, central grey, interpeduncular nucleus, locus coerulus, pontine reticular formation and cerebellum. Likewise, regions containing 5-HT axons of passage (e.g., indusium griseum and lateral hypothalamus) appeared to be insensitive to the neurotoxic effects of MDMA on 5-HT neurons. Furthermore, the neurotoxic effects of MDMA showed specificity in that the catecholamine neurons labeled by 3H-mazindol were unaffected by the treatment regimen. These data indicate that the preferential degeneration of serotonergic neurons by MDMA is mediated primarily at 5-HT terminal regions, whereas regions containing 5-HT perikarya and axons of passage remain relatively unaffected. In addition, the observed time-dependent reductions and recovery of 5-HT uptake sites which were detected within 2 weeks of the treatment regimen in certain brain regions suggest region-specific differences in recovery of 5-HT systems from MDMA-induced lesion.     

(+/-)3,4-Methylenedioxymethamphetamine ('Ecstasy')-induced serotonin neurotoxicity: studies in animals

The popular recreational drug, (+/-)3, 4-methylenedioxymethamphetamine (MDMA; 'Ecstasy') is a potent and selective brain serotonin (5-HT) neurotoxin in animals. MDMA-induced 5-HT neurotoxicity can be demonstrated using a variety of neurochemical, neuroanatomical and, more recently, functional measures of 5-HT neurons. Although the neurotoxic effects of MDMA in animals are widely accepted, the relevance of the animal data to human MDMA users has been questioned, largely because dosages of drugs used in animals are perceived as being much higher than those used by humans. In the present paper, we review the extensive body of data demonstrating that MDMA produced toxic effects on brain 5-HT neurons in animals and present new data indicating that levels of the type 2 vesicular monoamine transporter are reduced in MDMA-treated animals, providing further indication of MDMA's 5-HT neurotoxic potential. Further, we demonstrate, using principles of interspecies scaling, that dosages of MDMA known to be neurotoxic in animals fall squarely in the range of dosages used typically by recreational MDMA users.     

The neurotoxic effects of 3,4-methylenedioxymethamphetamine (MDMA) and methamphetamine on serotonin, dopamine, and GABA-ergic terminals: an in-vitro autoradiographic study in rats

Damage to serotonin (5-HT) terminals following doses of 3,4-methylenedioxymethamphetamine (MDMA) is well documented, and this toxicity is thought to be related to dopamine release that is potentiated by the 5-HT(2A/2C) agonist effects of the drug. Although MDMA and methamphetamine (METH) have some similar dopaminergic activities, they differ in their 5-HT agonistic properties. It is reasoned that the study of the resultant toxicity following equimolar doses of MDMA and METH on both dopamine and 5-HT terminals should offer a comparison of the ability of these drugs to induce neurotoxicity. In order to measure the toxic effects to the brain, rats were given equimolar doses of MDMA (40 mg/kg/day) and METH (32 mg/kg/day) in subcutaneously implanted osmotic minipumps for a period of 5 days, and in-vitro autoradiography using [3H]-paroxetine, [3H]-mazindol, [3H]-methylspiperone, and [3H]-flunitrazepam, was performed on brain sections. The results showed that METH was more toxic to 5-HT terminals than MDMA in forebrain regions, including the anterior cingulate, caudate nucleus, nucleus accumbens, and septum. METH was also more toxic than MDMA to dopamine terminals in the habenula, and posterior retrosplenial cortex. Therefore, we find that METH was more toxic to 5-HT and dopamine terminals in specific brain regions in both pre and post-synaptic sites following continuous equimolar dosing.     

D1 but not D4 Dopamine Receptors are Critical for MDMA-Induced Neurotoxicity in Mice

MDMA, an addictive psychostimulant-consumed worldwide, has the ability to induce neurotoxic effects and addiction in laboratory animals and in humans through its effects on monoaminergic systems. MDMA-induced neurotoxicity in mice occurs primarily in dopaminergic neurons and does not significantly affect the serotonergic system. As the neurotoxic effects of MDMA in mice involve excessive dopamine (DA) release, DA receptors are highly likely to play a role in MDMA neurotoxicity, but the specific dopamine receptor subtypes involved have not previously been determined definitively. In this study, dopamine D1 and D4 receptor knock-out mice (D1R^?/? and D4R^?/?) were used to determine whether these receptors are involved in MDMA neurotoxicity. D1R inactivation attenuated MDMA-induced hyperthermia, decreased the reduction of dopamine and dopamine metabolite levels, and protected against dopamine terminal loss and reactive astrogliosis as determined in the striatum, 7 days after MDMA treatment. In sharp contrast, inactivation of D4R did not prevent hyperthermia or the neurotoxic effects of MDMA. Altogether, these results indicate that D1R, but not D4R, plays a significant role in the dopaminergic striatal neurotoxicity observed after exposure to MDMA.     

(±)3,4-methylenedioxymethamphetamine ("ecstasy") treatment modulates expression of neurotrophins and their receptors in multiple regions of adult rat brain

(±)3,4-Methylenedioxymethamphetamine (MDMA), a widely used drug of abuse, rapidly reduces serotonin levels in the brain when ingested or administered in sufficient quantities, resulting in deficits in complex route-based learning, spatial learning, and reference memory. Neurotrophins are important for survival and preservation of neurons in the adult brain, including serotonergic neurons. In this study, we examined the effects of MDMA on the expression of brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) and their respective high-affinity receptors, tropomyosin receptor kinase (trk)B and trkC, in multiple regions of the rat brain. A serotonergic-depleting dose of MDMA (10 mg/kg × 4 at 2-hour intervals on a single day) was administered to adult Sprague-Dawley rats, and brains were examined 1, 7, or 24 hours after the last dose. Messenger RNA levels of BDNF, NT-3, trkB, and trkC were analyzed by using in situ hybridization with cRNA probes. The prefrontal cortex was particularly vulnerable to MDMA-induced alterations in that BDNF, NT-3, trkB, and trkC mRNAs were all upregulated at multiple time points. MDMA-treated animals had increased BDNF expression in the frontal, parietal, piriform, and entorhinal cortices, increased NT-3 expression in the anterior cingulate cortex, and elevated trkC in the entorhinal cortex. In the nigrostriatal system, BDNF expression was upregulated in the substantia nigra pars compacta, and trkB was elevated in the striatum in MDMA-treated animals. Both neurotrophins and trkB were differentially regulated in several regions of the hippocampal formation. These findings suggest a possible role for neurotrophin signaling in the learning and memory deficits seen following MDMA treatment.     

Panic disorder due to ingestion of single dose ecstasy

Ecstasy or MDMA (3,4 methylenedioxymethamphetamine) is a popularly consumed substance worldwide. There have been various reports documented in the literature that have attributed MDMA to precipitating the onset of a wide range of persistent psychiatric symptoms. Additionally, there is increasing evidence of a permanent injury to the serotonergic neurons. In this case report, a person demonstrating panic disorder after the ingestion of a single dose of MDMA is described and potential mechanisms of action are reviewed.