On Site Link: MDMA (Ecstasy) Metabolites and Neurotoxicity
On Site Link: MDMA Pharmacology

Wang X, Baumann MH, Xu H, Rothman RB
3,4-methylenedioxymethamphetamine (MDMA) administration to rats decreases brain tissue serotonin but not serotonin transporter protein and glial fibrillary acidic protein.
Synapse. 2004 Sep 15;53(4):240-8.
Previous experiments conducted in this laboratory showed that administration of high-dose D-fenfluramine (D-FEN) and p-chloroamphetamine (PCA) decreased 5-HT transporter (SERT) binding and tissue 5-HT by 30-60% in caudate and whole brain tissue 2 days and 2 weeks after drug administration. However, protein expression as determined by Western blot analysis did not change in either tissue or time point, except for a 30% decrease in the caudate 2 days after PCA administration. In the present study, we studied the effect of MDMA and 5,7-dihydroxytryptamine (5,7-DHT) on tissue 5-HT levels and the protein expression level of SERT and glial fibrillary acidic protein (GFAP), a validated neurotoxicity marker. HYPOTHESIS: MDMA administration decreases SERT expression. METHODS: Two weeks after MDMA administration (7.5 mg/kg i.p., q 2 h x 3 doses) or 2 weeks after i.c.v. administration of 5,7,-DHT (150 microg/rat), male Sprague-Dawley rats were sacrificed and the caudate, cortex, and hippocampal tissue collected. Western blots for SERT and GFAP were generated using published methods. Tissue 5-HT levels were determined by HPLC coupled to electrochemical detection. RESULTS: MDMA treatment decreased tissue 5-HT in cortex, hippocampus, and caudate by about 50%. However, MDMA treatment had no significant effect on expression level of SERT and GFAP in any brain region. In contrast, 5,7-DHT reduced tissue 5-HT by more than 90%, decreased SERT protein expression by 20-35%, and increased GFAP by 30-39%. CONCLUSION: These data suggest the MDMA treatment regimen used here does not cause degeneration of 5-HT nerve terminals. Viewed collectively with our previous results and other published data, these data indicate that MDMA-induced persistent 5-HT depletion may occur in the absence of axotomy. [Abstract] [PDF]

Pubill D, Canudas AM, Pallas M, Camins A, Camarasa J, Escubedo E.
Different glial response to methamphetamine- and methylenedioxymethamphetamine-induced neurotoxicity.
Naunyn Schmiedebergs Arch Pharmacol. 2003 May;367(5):490-9. Epub 2003 Apr 09.
The consequences of the neurotoxic insult induced by 3,4-methylenedioxymethamphetamine (MDMA, an amphetamine derivative with specific action on the serotonergic system) were compared with those of methamphetamine (a derivative with specific action on dopaminergic system) in rats. Both drugs induced a very similar loss of body weight, especially evident 24 h after treatment. Their hyperthermic profile was also very similar and was dependent on ambient temperature, corroborating the thermo-dysregulatory effect of both substances. Methamphetamine (four injections of 10 mg kg(-1) s.c. at 2-h intervals) induced the loss of dopaminergic (35%) but not of serotonergic, terminals in the rat striatum and, simultaneously, a significant increase in striatal peripheral-type benzodiazepine receptor density, pointing to a glial reaction. Evidence for this drug-induced astrogliosis was the increased heat shock protein 27 (HSP27) expression in striatum, cortex and hippocampus. MDMA (20 mg kg(-1) s.c. b.i.d. for 4 days) induced a similar dopaminergic lesion in the striatum 3 days post-treatment, which reversed 4 days later. An important neurotoxic effect on serotonergic terminals was also observed in the cortex, striatum and hippocampus 3 days post-treatment, which partially reversed 4 days later in the striatum and hippocampus. No microglial activation was noticeable at either 3 or 7 days after MDMA treatment. This lack of effect on microglial cells was assessed by [(3)H]PK 11195 binding and OX-6 immunostaining, which were unchanged in the striatum and cortex after MDMA treatment. A non-significant tendency to increase was noted in the hippocampus 3 days after MDMA treatment. Furthermore, in MDMA-treated rats, neither HSP27 expression nor an increase in HSP27 immunoreactivity were detected. This result, together with the lack of increase in glial fibrilliary acidic protein (GFAP) immunoreactivity, indicate no astroglial activation at either 3 or 7 days post-treatment. Without microglial activation, an inflammatory process would not accompany the lesion induced by MDMA. The differences in glial activation between methamphetamine and MDMA observed in the present study could have implications for the prognosis of the injury induced by these drugs. [Abstract]

Aguirre N, Barrionuevo M, Ramirez MJ, Del Rio J, Lasheras B.
Alpha-lipoic acid prevents 3,4-methylenedioxy-methamphetamine (MDMA)-induced neurotoxicity.
Neuroreport 1999 Nov 26;10(17):3675-80
"A single administration of 3,4-methylenedioxymethamphetamine (MDMA, 20 mg/kg, i.p.), induced significant hyperthermia in rats and reduced 5-hydroxytryptamine (5-HT) content and [3H]paroxetine-labeled 5-HT transporter density in the frontal cortex, striatum and hippocampus by 40-60% 1 week later. MDMA treatment also increased glial fibrillary acidic protein (GFAP) immunoreactivity in the hippocampus. Repeated administration of the metabolic antioxidant alpha-lipoic acid (100 mg/kg, i.p., b.i.d. for 2 consecutive days) 30 min prior to MDMA did not prevent the acute hyperthermia induced by the drug; however, it fully prevented the serotonergic deficits and the changes in the glial response induced by MDMA. These results further support the hypothesis that free radical formation is responsible for MDMA-induced neurotoxicity." [Abstract]

Kramer HK, Poblete JC, Azmitia EC.
3,4-Methylenedioxymethamphetamine ('Ecstasy') promotes the translocation of protein kinase C (PKC): requirement of viable serotonin nerve terminals.
Brain Res 1995 May 22;680(1-2):1-8
"The metabolic effects of the neurotoxic, ring-substituted amphetamine 3,4-methylenedioxy-methamphetamine (MDMA or 'Ecstasy') were examined in vivo. In this study, we focused on the ability of MDMA to induce a translocation of the calcium and phospholipid-dependent protein kinase C (PKC) from the cytosol to the cortical plasma membrane. Two injections of MDMA (20 mg/kg; 10 h apart; s.c.) increased the density of membrane bound PKC sites by 48.0% over saline treated animals without mediating a significant change in ligand ([3H]phorbol 12,13 dibutyrate; [3H]PDBu) affinity. Longer drug treatments (8 x 20 mg/kg) induced a lasting (up to 5 days post-treatment) increase in the density of membrane-bound PKC. Prior destruction of cortical 5-HT nerve terminals with p-chloroamphetamine (PCA) prevents this effect and suggests that viable 5-HT uptake sites are essential for MDMA-induced PKC translocation. These results demonstrate that MDMA-induced PKC translocation is mediated by viable cortical 5-HT nerve terminals, and that prolonged kinase activation may contribute to MDMA-induced serotonergic neurotoxicity." [Abstract]

Samuvel DJ, Jayanthi LD, Bhat NR, Ramamoorthy S.
A role for p38 mitogen-activated protein kinase in the regulation of the serotonin transporter: evidence for distinct cellular mechanisms involved in transporter surface expression.
J Neurosci. 2005 Jan 5;25(1):29-41.
The serotonin transporter (SERT) is regulated by various signaling mechanisms that may operate to maintain appropriate levels of synaptic serotonin (5-HT). We demonstrate that one of the mitogen-activated protein kinases (MAPKs), p38 MAPK, regulates SERT. Treatment of rat midbrain synaptosomes with p38 MAPK-specific inhibitors, PD169316 [4-(4-fluorophenyl)-2-(4-nitrophenyl)-5-(4-pyridyl)-1H-imidazole] or SB203580 [4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)-1H-imidazole], reduced 5-HT uptake. An additive SERT inhibition by PD169316 and beta-phorbol 12-myristate 13-acetate (beta-PMA) indicated the involvement of a protein kinase C (PKC)-independent MAPK pathway. Kinetic studies indicated a significant decrease in the transport capacity (V(max)) after PD169316 treatment of synaptosomes. Biotinylation studies showed reduced SERT proteins in the plasma membrane of synaptosomes after p38 MAPK inhibition and PKC activation. Phosphorylation studies using synaptosomes revealed decreased SERT phosphorylation by PD169316 but increased phosphorylation by beta-PMA. d-Amphetamine enhanced SERT basal phosphorylation and PD169316 blocked this effect. SERT interaction with protein phosphatase 2A catalytic subunit and syntaxin 1A decreased after PD169316 or beta-PMA treatment of synaptosomes. In synaptosomes, PKC activation but not p38 MAPK inhibition resulted in SERT redistribution from cholesterolrich lipid raft fractions to nonlipid raft fractions. The presence of phospho-p38 MAPK in synaptosomes and human embryonic kidney 293 (HEK-293) cells suggested the presence of constitutively active p38 MAPK in these preparations. Cotransfection of HEK-293 cells with SERT and a constitutively active form of MAP kinase kinase 3b(E) [MKK3b(E)] increased 5-HT transport, and RNA interference targeted to p38 MAPK inhibited 5-HT uptake, confirming the involvement of active p38 MAPK in SERT expression. Although PD169316 inhibited SERT insertion to the plasma membrane, beta-PMA increased SERT internalization in HEK-293 cells. Together, these results indicate a distinct role of p38 MAPK in SERT regulation. [Abstract]

Kramer HK, Poblete JC, Azmitia EC.
Characterization of the translocation of protein kinase C (PKC) by 3,4-methylenedioxymethamphetamine (MDMA/ecstasy) in synaptosomes: evidence for a presynaptic localization involving the serotonin transporter (SERT).
Neuropsychopharmacology 1998 Oct;19(4):265-77
"3, 4-methylenedioxymethamphetamine (MDMA or Ecstasy) is a substituted amphetamine whose acute and long-term effects on the serotonin system are dependent on an interaction with the 5-HT uptake transporter (SERT). Although much of the work dedicated to the study of this compound has focused on its ability to release monoamines, this drug has many important metabolic consequences on neurons and glial cells. The identification of these physiological responses will help to bridge the gap that exists in the information between the acute and neurotoxic effects of amphetamines. Substituted amphetamines have the ability to produce a long-term translocation of protein kinase C (PKC) in vivo, and this action may be crucial to the development of serotonergic neurotoxicity. Our earlier results suggested that PKC activation occurred through pre- and postsynaptic mechanisms. Because the primary site of action of these drugs is the 5-HT transporter, we now expand on our previous results and attempt to characterize MDMA's ability to translocate PKC within cortical 5-HT nerve terminals. In synaptosomes, MDMA produced a concentration-dependent increase in membrane-bound PKC (as measured by 3H-phorbol 12, 13 dibutyrate, 3H-PDBu) bindings sites. This response was abolished by cotreatment with the specific serotonin reuptake inhibitor (SSRI), fluoxetine, but not by the 5-HT2A/2C antagonist, ketanserin. In contrast, full agonists to 5-HT1A and 5-HT2 receptors did not produce significant PKC translocation. MDMA-mediated PKC translocation also requires the presence of extracellular calcium ions. Using assay conditions where extracellular calcium was absent prevented in vitro activation of PKC by MDMA. Prolonged PKC translocation has been hypothesized to contribute to the calcium-dependent neurotoxicity produced by substituted amphetamines. In addition, many physiological processes within 5-HT nerve terminals, including 5-HT reuptake and vesicular serotonin release, are susceptible to modification by PKC-dependent protein phosphorylation. Our results suggest that prolonged activation of PKC within the 5-HT nerve terminal may contribute to lasting changes in the homeostatic function of 5-HT neurons, leading to the degeneration of specific cellular elements after repeated MDMA exposure." [Abstract]

Bogen IL, Haug KH, Myhre O, Fonnum F.
Short- and long-term effects of MDMA ("ecstasy") on synaptosomal and vesicular uptake of neurotransmitters in vitro and ex vivo.
Neurochem Int. 2003 Sep-Oct; 43(4-5): 393-400.
"3,4-Methylenedioxymethamphetamine (MDMA, "ecstasy") is a commonly abused drug which has been shown to be neurotoxic to serotonergic neurons in many species. The exact mechanism responsible for the neurotoxicity of MDMA is, however, poorly understood. In this study, the effects of MDMA on the synaptosomal and vesicular uptake of neurotransmitters were investigated. Our results show that MDMA (0.5-20 microM) reduces both synaptosomal and vesicular uptake of serotonin and dopamine in a dose dependent manner in vitro, while the uptake of glutamate and gamma-aminobutyric acid (GABA) remains unaffected. Ex vivo experiments support the importance of the monoamines, with predominant dopaminergic inhibition at short-term exposure (3 x 15 mg/kg; 2-h intervals), and exclusively serotonergic inhibition at long-term exposure (2 x 10 mg/kg per day; 4 days). This study also compares MDMA and the structurally related antidepressant paroxetine, in an attempt to reveal possible cellular mechanisms for the serotonergic toxicity of MDMA. One important difference between paroxetine and MDMA is that only MDMA has the capability of inhibiting vesicular uptake of monoamines at doses used. We suggest that inhibition of the vesicular monoamine transporter-2, and a following increase in cytoplasmatic monoamine concentrations, might be crucial for the neurotoxic effect of MDMA." [Abstract]

Chen K.
Organization of MAO A and MAO B promoters and regulation of gene expression.
Neurotoxicology. 2004 Jan;25(1-2):31-6.
Monoamine oxidase (MAO) A and B play important roles in the metabolism of catecholamines and xenobiotics in the central nervous system and peripheral tissues. The ubiquitous presence of low level of MAO in all cells suggests essential functional for house keeping. Higher level of expression of MAO A and B also were observed in tissue and cell specific manner. The core promoter of human MAO A and B promoters have been characterized. Sp1 binding motifs were present in both promoters which constituted the major binding sites for Sp1 and Sp1-like family transcription factor binding, and other interaction proteins like Egr-1 in MAO B promoter. The presence of repeat units within the 2 kb human MAO A promoter which is associated with promoter activity and enzymatic activity in human fibroblast culture provided a tool to study human population with abnormal behaviors related to serotonin and other neurotransmitters. Conflicting results were reported from these studies due to the lack of basic understanding of MAO A promoter and the factors such as glucocorticoid which influences MAO A activity. Hopefully the enthusiasm will lead to more reliable tools to identify the major factor which caused the large difference in MAO A activity among human population. The overlapping Sp1/Egr-1/Sp1 binding site within MAO B promoter has been identified as the responsible element for PMA response. MAO B expression is selectively induced by the activation of protein kinase C and MAPK signal pathway. [Abstract]

Wai K. Wong, Xiao-Ming Ou, Kevin Chen, and Jean C. Shih
Activation of Human Monoamine Oxidase B Gene Expression by a Protein Kinase C MAPK Signal Transduction Pathway Involves c-Jun and Egr-1
J. Biol. Chem. 277: 22222-22230, 2002.
"Monoamine oxidases (MAO) A and B deaminate a number of biogenic amines. Aberrant expression of MAO is implicated in several psychiatric and neurogenerative disorders. In this study, we have shown that phorbol 12-myristate 13-acetate (PMA) increases human MAO B, but not MAO A, gene expression. The sequence between 246 and 225 bp consists of overlapping binding sites (Sp1/Egr-1/Sp1) that are recognized by Sp1, Sp3, and PMA-inducible Egr-1 is essential for PMA activation. PMA transiently increases egr-1 and c-jun gene expression. Mutation studies show that Egr-1 and c-Jun transactivate the MAO B promoter and increase endogenous MAO B transcripts via the Sp1/Egr-1/Sp1 overlapping binding sites. Sp3 inhibits Sp1 and Egr-1 activation of MAO B gene expression. c-fos gene expression was increased by PMA but not involved in MAO B gene transcription. Furthermore, protein kinase C inhibitor blocks the PMA-dependent activation of MAO B. Co-transfection of the MAO B promoter with dominant negative forms of Ras, Raf-1, MEKK1, MEK1, MEK3, MEK7, ERK2, JNK1, and p38/RK inhibit the PMA-dependent activation of the MAO B promoter. These results indicate that MAO B expression is selectively induced by the activation of protein kinase C and MAPK signaling pathway and that c-Jun and Egr-1 appear to be the ultimate targets of this regulation." [Full Text]

Salzmann J, Marie-Claire C, Le Guen S, Roques BP, Noble F.
Importance of ERK activation in behavioral and biochemical effects induced by MDMA in mice.
Br J Pharmacol. 2003 Nov; 140(5): 831-8. Epub 2003 Sep 29.
"Little is known about the cellular effects induced by 3,4-methylenedioxymethamphetamine (MDMA, ecstasy), although changes in gene expression have been observed following treatments with other psychostimulants. Thus, the aim of this study was to investigate in mice, the relationships between the ras-dependent protein kinase ERK and MDMA-induced reinforcement using the conditioned place preference (CPP) and locomotor activity measurements. This was completed using real-time quantitative PCR method by a study of immediate early-genes (IEGs) transcription known to be involved in neuronal plasticity. A significant CPP was observed after repeated MDMA treatment in CD-1 mice at a dose of 9 mg kg-1 i.p. but not at 3 and 6 mg kg-1. This rewarding effect was abolished by the selective inhibitor of ERK activation, SL327 (50 mg kg-1; i.p.). Similar results were obtained on MDMA-induced locomotor activity, clearly suggesting a role of ERK pathway in these behavioral responses. Following acute i.p. injection, MDMA induced a strong c-fos transcription in brain structures, such as caudate putamen, nucleus accumbens and hippocampus, whereas egr-1 and egr-3 transcripts were only increased in the caudate putamen. MDMA-induced IEGs transcription was selectively suppressed by SL327 in the caudate putamen, suggesting a role for other signaling pathways in regulation of IEGs transcription in the other brain structures. In agreement with these results, MDMA-induced c-fos protein expression was blocked by SL327 in the caudate putamen. This study confirms and extends to mice the reported role of ERK pathway in the development of addiction-like properties of MDMA. This could facilitate studies about the molecular mechanism of this process by using mutant mice." [Abstract]

Falk EM, Cook VJ, Nichols DE, Sprague JE.
An antisense oligonucleotide targeted at MAO-B attenuates rat striatal serotonergic neurotoxicity induced by MDMA.
Pharmacol Biochem Behav 2002 Jun;72(3):617-22
"The present study was designed to elucidate the role of dopamine (DA) metabolism in the serotonergic neurotoxicity induced by 3,4-methylenedioxymethamphetamine (MDMA). An antisense (AS) oligonucleotide (ODN) sequence targeted at monoamine oxidase-B (MAO-B) was utilized to attenuate MAO-B activity prior to MDMA administration. Sprague-Dawley rats were surgically implanted with intracerebroventricular (icv) cannulae and received a continuous infusion of MAO-B AS-ODN via an osmotic minipump. Constant AS ODN infusion for 7 days at a rate of 0.5 microl/h (total daily dose 600 pmol) resulted in a 63% knockdown of MAO-B activity. MDMA (40 mg/kg, sc) produced a rise in body temperature within 1 h of MDMA administration and a reduction in striatal serotonin (5-HT) and 5-hydroxyindole acetic acid (5-HIAA) levels 7 days later. Pretreatment with the MAO-B AS ODN prior to MDMA attenuated this reduction in serotonergic markers, yet had no effect on MDMA-induced hyperthermia. Furthermore, in vivo microdialysis revealed that previous AS ODN treatment failed to alter the acute DA release induced by MDMA (10 mg/kg, sc) within the striatum. These results indicate that MAO-B plays an integral role in the development of MDMA-induced neurotoxicity while not affecting MDMA-induced hyperthermia or acute DA release." [Abstract]

Sprague JE, Nichols DE.
The monoamine oxidase-B inhibitor L-deprenyl protects against 3,4-methylenedioxymethamphetamine-induced lipid peroxidation and long-term serotonergic deficits.
J Pharmacol Exp Ther. 1995 May;273(2):667-73.
3,4-Methylenedioxymethamphetamine (MDMA)-induced serotonergic neurotoxicity was assessed in the striatum, hippocampus and frontal cortex of rats by using [3H]paroxetine binding to label serotonin (5-HT) uptake sites and 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) levels as markers of serotonergic function. NMDA (40 mg/kg) induced a significant decrease in both [3H]paroxetine binding Bmax and 5-HT and 5-HIAA levels 7 days after treatment. The monoamine oxidase-B inhibitor L-deprenyl (2 mg/kg) administered 30 min before MDMA blocked these decreases. MDMA (40 mg/kg) also maximally increased the formation of thiobarbituric acid reactive substances (an indicator of lipid peroxidation) 12 hr after treatment in all three brain regions studied. This increase in malondialdehyde formation was also blocked by pretreatment with L-deprenyl. Tryptophan hydroxylase (TPH) activity was also significantly reduced 18 hr after MDMA. L-Deprenyl reversed this decrease in TPH activity. ..." [Abstract]

Stone DM, Hanson GR, Gibb JW.
In vitro reactivation of rat cortical tryptophan hydroxylase following in vivo inactivation by methylenedioxymethamphetamine.
J Neurochem. 1989 Aug;53(2):572-81.
The activity of tryptophan hydroxylase (EC 1.14.16.4) from rat brain was significantly decreased 1 h following a single systemic injection of 3,4-methylenedioxymethamphetamine (MDMA) when assessed ex vivo by radioenzymatic assay or in vivo by the quantitation of 5-hydroxytryptophan accumulation following central L-aromatic amino acid decarboxylase inhibition. Recovery of enzymatic activity in vivo, which occurred within 24 h of low-dose MDMA treatment, appeared not to involve synthesis of new enzyme protein, because the return of enzymatic activity was not prevented by prior cycloheximide. Acutely MDMA-depressed cortical tryptophan hydroxylase activity could be completely restored in vitro by a prolonged (20-24 h) anaerobic incubation in the presence of dithiothreitol and Fe2+ at 25 degrees C; partial reconstitution occurred when 2-mercapto-ethanol was substituted for dithiothreitol. Cortical tryptophan hydroxylase acutely inactivated by methamphetamine or p-chloroamphetamine could be similarly reactivated. MDMA-inactivated cortical tryptophan hydroxylase derived from rats killed later than 3 days after drug treatment could not be significantly reactivated under the conditions described above, indicating the development of irreversible enzymatic damage. Kinetic analysis of enzyme reactivation revealed an approximate doubling of enzyme Vmax with no change in enzyme affinity for either substrate, tryptophan, or pterin cofactor. These studies suggest that MDMA and its congeners inactivate central tryptophan hydroxylase by inducing oxidation of key enzyme sulfhydryl groups. The reactivation capacity of drug-inactivated enzyme at various times after MDMA treatment may provide a means of assessing the development of MDMA-induced neurotoxicity. [Abstract]

Yuan J, Cord BJ, McCann UD, Callahan BT, Ricaurte GA.
Effect of depleting vesicular and cytoplasmic dopamine on methylenedioxymethamphetamine neurotoxicity.
J Neurochem. 2002 Mar;80(6):960-9.
"The mechanism by which 3,4-methylenedioxymethamphetamine (MDMA) produces serotonin (5-HT) neurotoxicity is unknown but considerable evidence suggests that endogenous brain dopamine (DA) is involved. However, it has recently become apparent that some of the data implicating brain DA in MDMA neurotoxicity may be confounded by drug effects on thermoregulation. The purpose of the present studies was to examine the role of DA in MDMA neurotoxicity, while controlling for possible confounding effects of drug- induced changes in core temperature. Rats were treated with reserpine, alone and in combination with alpha-methyl-p -tyrosine (AMPT), to deplete vesicular and cytoplasmic stores of DA. When drug-induced hypothermia was averted (by raising ambient temperature), the 5-HT neuroprotective effects of reserpine and AMPT were no longer apparent. The lack of neuroprotection by AMPT and reserpine, alone and in combination, in studies that control for the effects of these drugs on core temperature, suggests that DA per se is not essential for the expression of MDMA-induced 5-HT neurotoxicity." [Abstract]

Saldana SN, Barker EL.
Temperature and 3,4-methylenedioxymethamphetamine alter human serotonin transporter-mediated dopamine uptake.
Neurosci Lett. 2004 Jan 16;354(3):209-12.
"Although studies have suggested that dopamine can be transported by serotonin transporters (SERTs), such activity has not been characterized at the cloned SERTs. Dopamine and serotonin uptake by human SERT expressed in HEK-293 cells was compared at 37 and 40 degrees C. Elevated temperature was found to alter serotonin transport, but had no significant effect on dopamine transport. These effects led to a 10-fold increase in the serotonin:dopamine transport ratio reflecting an increased preference of SERTs for dopamine as opposed to serotonin at the higher temperature. The effects of 3,4-methylenedioxymethamphetamine (MDMA) on SERT-mediated dopamine transport were also evaluated by pre-incubating SERT-expressing cells with MDMA. The presence of intracellular MDMA caused a decrease in [(3)H]dopamine uptake but had no effect on [(3)H]serotonin transport suggesting that intracellular MDMA may be capable of inhibiting transporter function." [Abstract]

Jones DC, Lau SS, Monks TJ
Thioether metabolites of 3,4-methylenedioxyamphetamine and 3,4-methylenedioxymethamphetamine inhibit human serotonin transporter (hSERT) function and simultaneously stimulate dopamine uptake into hSERT-expressing SK-N-MC cells.
J Pharmacol Exp Ther. 2004 Oct;311(1):298-306.
3,4-Methylenedioxyamphetamine (MDA) and 3,4-methyl-enedioxymethamphetamine (MDMA, ecstasy) are widely abused amphetamine derivatives that target the serotonin system. The serotonergic neurotoxicity of MDA and MDMA seems dependent on their systemic metabolism. 5-(Glutathion-S-yl)-alpha-methyldopamine [5-(GSyl)-alpha-MeDA] and 2,5-bis(glutathion-S-yl)-alpha-methyldopamine [2,5-bis(GSyl)-alpha-MeDA], metabolites of MDA and MDMA, are also selective serotonergic neurotoxicants and produce behavioral and neurochemical changes similar to those seen with MDA and MDMA. We now show that 5-(GSyl)-alpha-MeDA and 2,5-bis(GSyl)-alpha-MeDA are more potent than MDA and MDMA (K(i) = 69, 50, 107, and 102 microM, respectively) at inhibiting 5-hy-droxytryptamine (serotonin) transport into SK-N-MC cells transiently transfected with the human serotonin transporter (hSERT). Moreover, 5-(GSyl)-alpha-MeDA and 2,5-bis(GSyl)-alpha-MeDA simultaneously stimulated dopamine (DA) transport into the hSERT-expressing cells, an effect attenuated by fluoxetine, indicating that stimulated DA transport was hSERT-dependent. Finally, 5-(GSyl)-alpha-MeDA and 2,5-bis(GSyl)-alpha-MeDA, and to a lesser extent MDA and MDMA, induced a concentration and time-dependent increase in reactive oxygen species (ROS) in both hSERT and human dopamine transporter-transfected cells. Fluoxetine attenuated the increase in ROS generation in hSERT-expressing cells. The results are consistent with the view that the serotonergic neurotoxicity of MDA and MDMA may be mediated by the metabolism-dependent stimulation of DA transport into hSERT-expressing cells and ROS generation by redox active catechol-thioether metabolites and DA. [Abstract]

Ikemoto K, Kitahama K, Seif I, Maeda T, De Maeyer E, Valatx JL.
Monoamine oxidase B (MAOB)-containing structures in MAOA-deficient transgenic mice.
Brain Res 1997 Oct 10;771(1):121-32
"Monoamine oxidase (MAO)-containing structures were studied for the first time in type A MAO (MAOA)-deficient transgenic mice (Tg8) derived from C3H strain, using MAO enzyme histochemistry. In this mutant line, MAOA activity was not detected in neurons of the locus coeruleus. In contrast, in their dorsal raphe neurons, we noted an intense activity of type B MAO (MAOB). Based on pharmacological MAOA suppression experiments employing a specific inhibitor (clorgyline), we confirmed that the localization of MAOB-positive structures are not different between Tg8 mutant and normal C3H line. Many of MAOB-positive structures which have not been described previously in the rat, cat and primates were described in this study. In the forebrain, MAOB-containing neurons were discriminated in the striatum, septal nuclei, major island of Calleja, diagonal band, medial forebrain bundle, ventral pallidum and amygdaloid nucleus. Stained neurons in the thalamus and hypothalamus were much more extensively distributed in the mouse than the rat. Pontine laterodorsal tegmental neurons showed MAOB activity. The present data suggest that serotonin, a preferential substrate for MAOA, can be oxidized by MAOB in MAOA-deficient Tg8 mice." [Abstract]

Luque JM, Kwan SW, Abell CW, Da Prada M, Richards JG.
Cellular expression of mRNAs encoding monoamine oxidases A and B in the rat central nervous system.
J Comp Neurol. 1995 Dec 25;363(4):665-680.
Monoamine oxidases A and B (MAO-A and MAO-B) oxidatively deaminate neurotransmitter and xenobiotic amines. The cellular localization of these isoenzymes in the central nervous system (CNS) differs markedly and only partly reflects the distribution of their presumed natural substrates. In the present study, by using in situ hybridization with 35S-labelled oligonucleotide probes, we examined the distribution of mRNAs encoding MAO-A and MAO-B in the rat CNS. Probes for tyrosine hydroxylase, histidine decarboxylase, and tryptophan hydroxylase mRNAs were used to demonstrate the catecholaminergic, histaminergic, or serotoninergic nature of some cell populations in adjacent sections. The radioligands [3H]-Ro 41-1049 and [3H]lazabemide (reversible and selective inhibitors of MAO-A and MAO-B, respectively) were used to reveal the protein distribution by enzyme radioautography. The distribution and abundance of transcripts for both isoenzymes in the tissues investigated differed markedly but, in general, correlated with the protein distribution. MAO-A mRNA and protein were most abundant in noradrenergic neurons. However, moderate levels of transcript expression and protein were also detected in the serotoninergic neurons, and low but significant levels were detected in the dopaminergic neurons. An unexpectedly remarkable degree of hybridization signal was apparent in nonaminergic cell populations, e.g., in the cerebral cortices, the hippocampal formation (CA1-3, dentate gyrus), the cerebellar granule cell layer, and the spinal cord motoneurons. In contrast, MAO-B mRNA and protein were most abundant in serotoninergic and histaminergic neurons, Bergmann glial cells, and circumventricular organs, including the ependyma. MAO-B transcripts were also weakly expressed in nonaminergic cells, e.g., in the hippocampal formation (CA1-2). A further nonneuronal localization of MAO-B transcripts was also resolved, e.g., in the glia limitans, the olfactory nerve layer, and the cerebellar peduncle. These findings reveal further the potential of various cell populations to synthesize the isoenzymes, and homologous (aminergic) and heterologous (nonaminergic) patterns of expression as well as coexpression of MAO mRNAs are described. [Abstract]

Arai R, Kimura H, Nagatsu I, Maeda T.
Preferential localization of monoamine oxidase type A activity in neurons of the locus coeruleus and type B activity in neurons of the dorsal raphe nucleus of the rat: a detailed enzyme histochemical study.
Brain Res 1997 Jan 16;745(1-2):352-6
"Using enzyme histochemistry for monoamine oxidase (MAO) activity, we have examined whether MAO type A or type B or both are localized in neurons of the locus coeruleus (LC) and dorsal raphe nucleus (DR) of the rat. After pretreatment with various concentrations of the MAO type A inhibitor clorgyline or the type B inhibitor deprenyl, non-fixed frozen sections of the brain were histochemically stained for MAO activity with tyramine as a common substrate for the two types. MAO activity of the stained neuron was determined by measuring optical density of the staining. Percentage inhibition of the control MAO activity was plotted against increasing concentrations of the inhibitors. MAO activity of LC neurons was inhibited by low concentrations of clorgyline with a monophasic dose-response curve but not with a biphasic curve. Higher concentrations of deprenyl were needed to inhibit of LC neurons. MAO activity of DR neurons was inhibited by low concentrations of deprenyl with a monophasic dose-response curve. Clorgyline inhibited the MAO activity of DR neurons at only higher concentrations. When the sections without inhibitor pretreatment were incubated with the type A preferential substrate serotonin, the MAO activity was strongly stained in LC neurons but very weakly in DR neurons. With the type B preferential substrate beta-phenylethylamine, the staining was intense in DR neurons while very faint in LC neurons. These findings suggest that (i) almost all the MAO activity in LC neurons is of type A, and (ii) the MAO activity in DR neurons is predominantly of type B." [Abstract]

Rudnick G, Wall SC.
Non-neurotoxic amphetamine derivatives release serotonin through serotonin transporters.
Mol Pharmacol 1993 Feb;43(2):271-6
"3,4-Methylenedioxymethamphetamine (MDMA) and several other amphetamine derivatives cause degeneration of serotonergic nerve terminals. These drugs also release serotonin from nerve terminals both in vivo and in vitro. Two non-neurotoxic derivatives of MDMA were tested in membrane vesicle model systems to determine whether they also lacked the ability to release serotonin. 3-Methoxy-4-methylamphetamine (MMA) and 5-methoxy-6-methyl-2-aminoindan (MMAI) both inhibited imipramine binding to serotonin transporters in platelet plasma membrane vesicles and both inhibited Na+ gradient-driven serotonin transport into those vesicles. Significantly, both MMA and MMAI released [3H]serotonin from plasma membrane vesicles, apparently by a process of exchange. The half-maximal concentrations for this effect were comparable to that reported for MDMA. In addition to their effects on plasma membrane transporters, MMA and MMAI both inhibited serotonin transport into chromaffin granule membrane vesicles catalyzed by the vesicular biogenic amine transporter. At higher concentrations, these compounds also caused release of [3H]serotonin from chromaffin granule membrane vesicles and dissipated the transmembrane pH difference (delta pH). Although MMAI effects on the serotonin transporter were similar to those of MDMA, the two compounds had different effects on dopamine transporters. MDMA and methamphetamine inhibited binding of a cocaine analog to the dopamine transporter and released dopamine accumulated by cells expressing dopamine transporters, but similar concentrations of MMAI were inactive." [Abstract]

Johnson MP, Nichols DE.
Combined administration of a non-neurotoxic 3,4-methylenedioxymethamphetamine analogue with amphetamine produces serotonin neurotoxicity in rats.
Neuropharmacology 1991 Jul;30(7):819-22
"In the present study, a central serotonin neurotoxicity was induced by combining a non-neurotoxic 3,4-methylenedioxymethamphetamine analogue, 5-methoxy-6-methyl-2-aminoindan (MMAI), with the non-vesicular dopamine (DA) releaser, S-(+)-amphetamine (Amp). With the multiple dosing regimen utilized neither drug alone resulted in any changes in serotonergic parameters, including 5-HT, 5-HIAA and the number of 5-HT uptake sites. However, MMAI (10 mg/kg) in combination with Amp (2 x 2.5 mg/kg) did result in a long-term 20% decrease in cortical serotonergic parameters. The same dose of Amp plus 20 mg/kg MMAI resulted in a 50 to 60% reduction. Effects in the hippocampus and caudate nucleus were similar. These data support the hypothesis that DA release plays a critical role in the serotonin neurotoxicity of substituted amphetamines."
[Abstract]

Beveridge TJ, Mechan AO, Sprakes M, Pei Q, Zetterstrom TS, Green AR, Elliott JM.
Effect of 5-HT depletion by MDMA on hyperthermia and Arc mRNA induction in rat brain.
Psychopharmacology (Berl). 2004 Jan 20 [Epub ahead of print]
"RATIONALE. 3,4-Methylenedioxymethamphetamine (MDMA) administration to rats produces an acute hyperthermic response and induces localised neuronal activation, which can be visualised via expression of immediate-early genes. The pharmacological and anatomical basis of these effects are unclear. At high doses, MDMA also causes selective neurotoxicity at serotonergic nerve terminals. OBJECTIVE. We investigated the effect of 5-hydroxytryptamine (5-HT) depletion on the acute hyperthermic response to MDMA and the pattern of neuronal excitation indicated by Arc (activity-regulated cytoskeleton associated gene) in naive rats and following administration of MDMA at a neurotoxic dose. METHODS. Expression of Arc mRNA was investigated by in situ hybridisation histochemistry using (35)S-labelled oligonucleotide probe. RESULTS. MDMA induced a significant hyperthermia together with increased Arc mRNA expression in cortical regions, caudate-putamen and CA1 hippocampus but not hypothalamus. At 21 days after a neurotoxic dose of MDMA, brain 5-HT and 5-HIAA levels were significantly reduced by 21-32%. In these animals, both the hyperthermic response and the pattern and extent of Arc mRNA expression induced by a subsequent dose of MDMA were unaltered. However, basal Arc expression was significantly increased in cortical regions and CA1 hippocampus. CONCLUSION. We conclude that the acute hyperthermic response induced by MDMA is not attenuated by moderate depletion of 5-HT, further questioning mediation via a serotonergic mechanism. Arc mRNA induction by MDMA exhibits highly localised expression, which is not altered following 5-HT depletion. However, following a neurotoxic dose of MDMA, basal expression of Arc is increased, particularly in cortex and CA1, suggesting that mechanisms underlying synaptic plasticity might also be modified." [Abstract]

Hansen, J. Paul, Riddle, Evan L., Sandoval, Veronica, Brown, Jeffrey M., Gibb, James W., Hanson, Glen R., Fleckenstein, Annette E.
Methylenedioxymethamphetamine Decreases Plasmalemmal and Vesicular Dopamine Transport: Mechanisms and Implications for Neurotoxicity
J Pharmacol Exp Ther 2002 300: 1093-1100
"Administration of a high-dose regimen of methamphetamine (METH) rapidly and profoundly decreases plasmalemmal and vesicular dopamine (DA) transport in the striatum, as assessed in synaptosomes and purified vesicles, respectively. To determine whether these responses were common to other amphetamines of abuse, effects of methylenedioxymethamphetamine (MDMA) on the plasmalemmal DA transporter (DAT) and vesicular monoamine transporter-2 (VMAT-2) were assessed. Similar to effects of METH reported previously, multiple high-dose MDMA administrations rapidly (within 1 h) decreased plasmalemmal DA uptake, as assessed ex vivo in synaptosomes prepared from treated rats. Unlike effects of multiple METH injections, this deficit was reversed completely 24 h after drug treatment. Also in contrast to effects of multiple METH injections, 1) MDMA caused little or no decrease in binding of the DAT ligand WIN35428, and 2) neither prevention of hyperthermia nor prior depletion of DA prevented the MDMA-induced reduction in plasmalemmal DA transport. However, a role for phosphorylation was suggested because pretreatment with protein kinase C inhibitors attenuated the deficit caused by MDMA in an in vitro model system. In addition to affecting DAT function, MDMA rapidly decreased vesicular DA transport as assessed in striatal vesicles prepared from treated rats. Unlike effects of multiple METH injections reported previously, this decrease partially recovered by 24 h after drug treatment. Taken together, these results reveal several differences between effects of MDMA and previously reported METH on DAT and VMAT-2; differences that may underlie the dissimilar neurotoxic profile of these agents." [Full Text]

Cowell RM, Kantor L, Hewlett GH, Frey KA, Gnegy ME.
Dopamine transporter antagonists block phorbol ester-induced dopamine release and dopamine transporter phosphorylation in striatal synaptosomes.
Eur J Pharmacol 2000 Feb 11;389(1):59-65
"We have reported that inhibition of protein kinase C blocks the Ca(2+)-independent reverse transport of dopamine mediated by amphetamine. In this study we investigated whether activation of protein kinase C by 12-O-tetradecanoyl phorbol-13-acetate (TPA) would mediate dopamine release through the plasmalemmal dopamine transporter. TPA, at 250 nM, increased the release of dopamine from rat striatal slices and synaptosomes while the inactive phorbol ester, 4alpha-phorbol, was ineffective. The TPA-mediated dopamine release was independent of extracellular calcium and was blocked by a selective protein kinase C inhibitor, Ro31-8220. The dopamine transporter antagonists, cocaine and GBR 12935 blocked the TPA-mediated dopamine release. In addition, cocaine blocked TPA-mediated phosphorylation of the plasmalemmal dopamine transporter. These results suggest that activation of protein kinase C results in reverse transport of dopamine through the plasmalemmal dopamine transporter and the phosphorylated substrate could be the dopamine transporter." [Abstract]

Schuldiner, S, Steiner-Mordoch, S, Yelin, R, Wall, SC, Rudnick, G
Amphetamine derivatives interact with both plasma membrane and secretory vesicle biogenic amine transporters
Mol Pharmacol 1993 44: 1227-1231
"The interaction of fenfluramine, 3,4-methylenedioxymethamphetamine (MDMA), and p-chloroamphetamine (PCA) with the platelet plasma membrane serotonin transporter and the vesicular amine transporter were studied using both transport and binding measurements. Fenfluramine is apparently a substrate for the plasma membrane transporter, and consequently inhibits both serotonin transport and imipramine binding. Moreover, fenfluramine exchanges with internal [3H]serotonin in a plasma membrane transporter-mediated reaction that requires NaCl and is blocked by imipramine. These properties are similar to those of MDMA and PCA as previously described. In adrenal chromaffin granule membrane vesicles containing the vesicular amine transporter, fenfluramine inhibited serotonin transport and dissipated the transmembrane pH difference (delta pH) that drives amine uptake. The use of [3H]reserpine-binding measurements to determine drug interaction with the vesicular amine transporter allowed assessment of the relative ability of MDMA, PCA, and fenfluramine to bind to the substrate site of the vesicular transporter. These measurements permit a distinction between inhibition of vesicular serotonin transport by directly blocking vesicular amine transport and by dissipating delta pH. The results indicate that MDMA and fenfluramine inhibit by both mechanisms but PCA dissipates delta pH without blocking vesicular amine transport directly." [Abstract]

Leonardi ET, Azmitia EC.
MDMA (ecstasy) inhibition of MAO type A and type B: comparisons with fenfluramine and fluoxetine (Prozac).
Neuropsychopharmacology 1994 Jul;10(4):231-8
"3,4-Methylenedioxymethamphetamine (MDMA), a serotonin (5-HT) neurotoxin, has been shown to promote the release of serotonin (5-HT) and block its reuptake. The increased buildup of extracellular 5-HT should normally be degraded by monoamine oxidase (MAO). The effects of both enantiomers of MDMA were examined on MAO-A and monoamine oxidase-B (MAO-B) activity in rat brain homogenates. Both enantiomers competitively inhibited 5-HT catabolism by rat brain MAO-A. The Ki of MDMA for MAO-A was 22 mumol/L. A mixed type of inhibition by MDMA was observed for phenethylamine catabolism by MAO-B for both optical antipodes. Logistical analysis of concentration response curves for MDMA inhibition of MAO-A and MAO-B show an IC50 of 44 mumol/L for inhibition of MAO-A by MDMA. The IC50 value of MDMA inhibition of MAO-B was 370 mumol/L, showing a selective potency for MAO-A inhibition. The MAO inhibitory properties of fenfluramine (FEN) and fluoxetine (FLUOX) were compared to those of MDMA. The rank order potency of these drugs for MAO-A inhibition was MDMA > FLUOX > FEN, whereas for MAO-B inhibition, FLUOX > MDMA > FEN. A combination of FLUOX and MDMA at their respective IC50 did not inhibit MAO activity more than either drug alone at equivalent concentrations. These results indicate that the actions of FEN do not appear to involve MAO inhibition. MDMA (ecstasy) produced a preferential inhibition of MAO-A (IC50 = 44 mumol/L), which should increase extracellular 5-HT." [Abstract]

de la Torre R, Farré M
Neurotoxicity of MDMA (ecstasy): the limitations of scaling from animals to humans.
Trends Pharmacol Sci. 2004 Oct;25(10):505-8.
Several studies suggest that MDMA-induced acute toxicity and long-term neurotoxicity is dependent on the metabolic disposition of MDMA. Differences in MDMA metabolism among animal species might therefore account for different sensitivities to its neurotoxic effects. The kinetic parameters of enzymes that regulate the formation of neurotoxic metabolites of MDMA differ among species, as does the ability of MDMA to self-inhibit these enzymes and the degree of genetic polymorphisms exhibited by these enzymes. Such features limit allometric scaling across animal models. [Abstract]

Colado MI, O'Shea E, Green AR
Acute and long-term effects of MDMA on cerebral dopamine biochemistry and function.
Psychopharmacology (Berl). 2004 May;173(3-4):249-63.
RATIONALE AND OBJECTIVES: The majority of experimental and clinical studies on the pharmacology of 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) tend to focus on its action on 5-HT biochemistry and function. However, there is considerable evidence for MDMA having marked acute effects on dopamine release. Furthermore, while MDMA produces long-term effects on 5-HT neurones in most species examined, in mice its long-term effects appear to be restricted to the dopamine system. The objective of this review is to examine the actions of MDMA on dopamine biochemistry and function in mice, rats, guinea pigs, monkeys and humans. RESULTS AND DISCUSSION: MDMA appears to produce a major release of dopamine from its nerve endings in all species investigated. This release plays a significant role in the expression of many of the behaviours that occur, including behavioural changes, alterations of the mental state in humans and the potentially life-threatening hyperthermia that can occur. While MDMA appears to be a selective 5-HT neurotoxin in most species examined (rats, guinea pigs and primates), it is a selective dopamine neurotoxin in mice. Selectivity may be a consequence of what neurotoxic metabolites are produced (which may depend on dosing schedules), their selectivity for monoamine nerve endings, or the endogenous free radical trapping ability of specific nerve endings, or both. We suggest more focus be made on the actions of MDMA on dopamine neurochemistry and function to provide a better understanding of the acute and long-term consequences of using this popular recreational drug. [Abstract]

Fantegrossi WE, Woolverton WL, Kilbourn M, Sherman P, Yuan J, Hatzidimitriou G, Ricaurte GA, Woods JH, Winger G
Behavioral and neurochemical consequences of long-term intravenous self-administration of MDMA and its enantiomers by rhesus monkeys.
Neuropsychopharmacology. 2004 Jul;29(7):1270-81.
The effects of self-administered 3,4-methylenedioxymethamphetamine (MDMA) on behavior and neurochemistry have not been previously studied in laboratory primates. We investigated the capacity of MDMA and its enantiomers to maintain contingent responding over an extended duration, whether any decrements in the reinforcing effects of these compounds would be observed over time, whether such decrements would be MDMA-selective, and whether any neurochemical correlates could be identified. Animals were previously trained to self-administer cocaine, then exposed to periodic substitutions of various doses of racemic MDMA and its enantiomers; full dose-effect curves were generated for each MDMA compound repeatedly over the duration of the study. After approximately 18 months of MDMA self-administration, drug exposure was halted and after at least 2 months drug abstinence, animals were scanned using positron emission tomography (PET) with the vesicular monoamine transporter (VMAT) ligand dihydrotetrabenazine (DTBZ). Shortly thereafter, animals were euthanized, brains were dissected, and samples were assayed for brain monoamines and their metabolites using high-performance liquid chromatography (HPLC), and for VMAT using DTBZ binding. The reinforcing effects of racemic and R(-)-MDMA were reduced over a long series (months) of individual self-administration access periods; the reinforcing effects of S+-MDMA were more resistant to this effect, but were attenuated for one animal. The reinforcing effects of cocaine were not altered by chronic MDMA self-administration, nor was the VMAT binding potential as assessed by PET. Further, there were no measurable decrements in serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC) or VMAT in any brain regions assayed. The reinforcing effects of MDMA are selectively attenuated by chronic MDMA self-administration, although this behavioral change appears to occur in the absence of any frank neurochemical correlates of toxicity. [Abstract]

Daumann J, Fischermann T, Pilatus U, Thron A, Moeller-Hartmann W, Gouzoulis-Mayfrank E
Proton magnetic resonance spectroscopy in ecstasy (MDMA) users.
Neurosci Lett. 2004 May 20;362(2):113-6.
The popular recreational drug 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) has well-recognized neurotoxic effects upon central serotonergic systems in animal studies. In humans, the use of MDMA has been linked to cognitive problems, particularly to deficits in long-term memory and learning. Recent studies with proton magnetic resonance spectroscopy (1H MRS) have reported relatively low levels of the neuronal marker N-acetylaspartate (NAA) in MDMA users, however, these results have been ambiguous. Moreover, the only available 1H MRS study of the hippocampus reported normal findings in a small sample of five MDMA users. In the present study, we compared 13 polyvalent ecstasy users with 13 matched controls. We found no differences between the NAA/creatine/phosphocreatine (Cr) ratios of users and controls in neocortical regions, and only a tendency towards lower NAA/Cr ratios in the left hippocampus of MDMA users. Thus, compared with cognitive deficits, 1H MRS appears to be a less sensitive marker of potential neurotoxic damage in ecstasy users. [Abstract]

Lyvers M, Hasking P
Have Halpern et al. (2004) detected 'residual neuropsychological effects' of MDMA? Not likely.
Drug Alcohol Depend. 2004 Aug 16;75(2):149-52; discussion 153. [Abstract]

Halpern JH, Pope HG, Sherwood AR, Barry S, Hudson JI, Yurgelun-Todd D
Residual neuropsychological effects of illicit 3,4-methylenedioxymethamphetamine (MDMA) in individuals with minimal exposure to other drugs.
Drug Alcohol Depend. 2004 Aug 16;75(2):135-47.
BACKGROUND: A substantial literature suggests that users of illicit 3,4-methylenedioxymethamphetamine (MDMA or "ecstasy") display residual cognitive deficits. Most MDMA users, however, use other illicit drugs as well, so it is difficult to be certain that these deficits are due to MDMA, as opposed to other drug use or additional confounding factors. METHODS: We administered a battery of neuropsychological tests to 23 young MDMA users who reported minimal exposure to any other drugs, including alcohol, and to 16 comparison individuals equally involved with the rave subculture, but reporting no MDMA use. We compared the groups by regression analyses adjusting for numerous potentially confounding variables. To test for a possible dose-response effect, we also performed a median split of 12 moderate MDMA users (22-50 lifetime uses) and 11 heavy users (60-450 uses), and compared these subgroups with non-users. RESULTS: MDMA users as a whole performed worse than non-users on most test measures, but these comparisons rarely reached statistical significance. This picture changed markedly in the subgroup analysis: although moderate users displayed virtually no differences from non-users on any measures, the heavy users displayed significant deficits on many measures, particularly those associated with mental processing speed and impulsivity. These differences did not appear explainable by differences in family-of-origin variables, verbal IQ, levels of depression, or time since last MDMA use. CONCLUSIONS: The presence of residual cognitive deficits, even among unusually "pure" frequent users of illicit MDMA, analyzed with adjustment for confounding variables, augments the evidence that MDMA itself, rather than some associated factor, is responsible for the deficits observed. [Abstract]

de Win MM, Reneman L, Reitsma JB, den Heeten GJ, Booij J, van den Brink W
Mood disorders and serotonin transporter density in ecstasy users--the influence of long-term abstention, dose, and gender.
Psychopharmacology (Berl). 2004 May;173(3-4):376-82.
RATIONALE: Neurotoxic effects of 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") on the serotonin (5-HT) system have been described in animals and humans, but little is known about long-term effects of ecstasy use on mood. OBJECTIVES: To investigate short-term and long-term effects of ecstasy use on mood and its association with 5-HT neurotoxicity, dose, and gender in humans. METHODS: Fifteen moderate ecstasy users, 23 heavy ecstasy users, 16 former heavy ecstasy users and 15 drug-using, but ecstasy-naive controls were included. Mood was assessed using the Composite International Diagnostic Interview (CIDI) and the Beck Depression Inventory (BDI). Outcomes were correlated with 5-HT transporter (SERT) density, assessed with [123I]beta-CIT single photon emission computed tomography (SPECT). RESULTS: The prevalence of mood disorders assessed by CIDI did not differ between all groups. The overall test for differences in BDI scores between groups was near significance (P=0.056), with BDI scores higher in former heavy ecstasy users than in ecstasy-naive controls (P=0.045). BDI scores were correlated with the total number of ecstasy tablets used (r=0.310; P=0.021). No associations between CIDI or BDI outcomes and SERT density or gender were observed. CONCLUSIONS: These results suggest that ecstasy use is not associated with clinical depression (CIDI). However, the number of ecstasy tablets taken lifetime was associated with higher BDI scores for depressive mood, and this relationship seemed to persist after ecstasy use had stopped. We did not find that depressed mood in ecstasy users was associated with decrease in SERT density. Prospective studies are needed to establish the causal relationship between ecstasy use and depressed mood. [Abstract]

Daumann J, Hensen G, Thimm B, Rezk M, Till B, Gouzoulis-Mayfrank E
Self-reported psychopathological symptoms in recreational ecstasy (MDMA) users are mainly associated with regular cannabis use: further evidence from a combined cross-sectional/longitudinal investigation.
Psychopharmacology (Berl). 2004 May;173(3-4):398-404.
RATIONALE: 3,4-Methylenedioxymethamphetamine (MDMA, ecstasy) has become a widely used recreational drug among young people. This is of great concern, since MDMA is neurotoxic in animal studies and its use has been associated with psychological distress and a variety of self-reported psychiatric symptoms. However, exploring the origins of psychopathology in ecstasy users is hampered by the frequent polydrug use and by the cross-sectional design of all investigations, so far. OBJECTIVES: The present study combines a cross-sectional with a longitudinal approach to further clarify the impact of the use of other illicit drugs on psychopathological symptoms reported by ecstasy users. METHODS: At baseline, we administered self-rating scales for impulsivity, sensation seeking and general psychological complaints to 60 recreational ecstasy users and 30 matched controls. From the initial sample of ecstasy users, 38 subjects were re-examined 18 months later. RESULTS. At baseline, ecstasy users reported significantly more psychological complaints than controls. However, self-reported psychopathology was mainly associated with regular cannabis use. At follow-up, subjects who had abstained from ecstasy use during the follow-up period did not differ from those reporting continued consumption. In contrast, subjects with regular concomitant cannabis use during the follow-up period reported more anxiety, interpersonal sensitivity and obsessive-compulsive behaviour than cannabis-abstinent users. Finally, higher levels of obsessive-compulsive behaviour, interpersonal sensitivity, depression, anxiety, phobic anxiety and paranoid ideation were significantly correlated with the duration of regular interim cannabis use. CONCLUSIONS: The present findings suggest that self-reported psychopathology in ecstasy users is predominantly attributable to concomitant use of cannabis. Abstinence from cannabis and not ecstasy seems to be a reliable predictor for remission of psychological complaints in ecstasy users. [Abstract]

Gudelsky GA.
Effect of ascorbate and cysteine on the 3,4-methylenedioxymethamphetamine-induced depletion of brain serotonin.
J Neural Transm. 1996;103(12):1397-404.
"The extent of long-term depletion of serotonin (5-HT) produced by 3,4-methylenedioxymethamphetmaine (MDMA) was assessed in rats treated with the antioxidants sodium ascorbate or L-cysteine. There was a 30-35% reduction in the striatal concentration of 5-HT 7 days following a single injection of MDMA (20 mg/kg, s.c.). MDMA had no significant effect on striatal concentrations of 5-HT in rats that had been treated with ascorbate (250 mg/kg, i.p.) or cysteine (500 mg/kg, i.p.) 30 min prior to and 5 hrs following the administration of MDMA. Treatment with ascorbate or cysteine did not alter the accumulation of MDMA in brain as determined by in vivo microdialysis. Moreover, neither ascorbate nor cysteine altered the stimulation of dopamine release elicited by MDMA. These data are supportive of the view that MDMA-induced toxicity of 5-HT neurons may be related to the production of free radicals and subsequent oxidative damage." [Abstract]

Shankaran M, Yamamoto BK, Gudelsky GA.
Ascorbic acid prevents 3,4-methylenedioxymethamphetamine (MDMA)-induced hydroxyl radical formation and the behavioral and neurochemical consequences of the depletion of brain 5-HT.
Synapse. 2001 Apr;40(1):55-64.
"MDMA-induced 5-HT neurotoxicity has been proposed to involve oxidative stress due to increased formation of hydroxyl radicals. Recently, MDMA-induced 5-HT neurotoxicity has been shown to be accompanied by a suppression of behavioral and neurochemical responses to a subsequent injection of MDMA. The intent of the present study was to examine whether suppression of the MDMA-induced formation of hydroxyl radicals by an antioxidant, ascorbic acid, attenuates both the MDMA-induced depletion of 5-HT and the functional consequences associated with this depletion. Treatment of rats with ascorbic acid suppressed the generation of hydroxyl radicals, as evidenced by the production of 2,3-dihydroxybenzoic acid from salicylic acid, in the striatum during the administration of a neurotoxic regimen of MDMA. Ascorbic acid also attenuated the MDMA-induced depletion of striatal 5-HT content. In rats treated with a neurotoxic regimen of MDMA, the ability of a subsequent injection of MDMA to increase the extracellular concentration of 5-HT in the striatum, elicit the 5-HT behavioral syndrome, and produce hyperthermia was markedly reduced compared to the responses in control rats. The concomitant administration of ascorbic acid with the neurotoxic regimen of MDMA prevented the diminished neurochemical and behavioral responses to a subsequent injection of MDMA. Finally, a neurotoxic regimen of MDMA produced significant reductions in the concentrations of vitamin E and ascorbic acid in the striatum and hippocampus. Thus, the MDMA-induced depletion of brain 5-HT and the functional consequences thereof appear to involve the induction of oxidative stress resulting from an increased generation of free radicals and diminished antioxidant capacity of the brain." [Abstract]

Zhou JF, Chen P, Zhou YH, Zhang L, Chen HH.
3,4-Methylenedioxymethamphetamine (MDMA) abuse may cause oxidative stress and potential free radical damage.
Free Radic Res. 2003 May; 37(5): 491-7.
"OBJECTIVE: To investigate whether 3,4-methylenedioxymethamphetamine abuse (MDMA abuse) may cause oxidative stress and potential free radical damage in the bodies of MDMA abusers (MA), and to explore the mechanisms by which MDMA abuse may be causing oxidative stress. METHODS: One hundred and twenty MA and 120 healthy volunteers (HV) were enrolled in a random control study design, in which the level of lipoperoxide (LPO) in erythrocytes, and the levels of Vitamin C (VC), Vitamin E (VE) and beta-carotene (beta-CAR) in plasma as well as the activities of superoxide dismutase (SOD) and catalase (CAT) in erythrocytes were determined by spectrophotometric methods. RESULTS: Compared with the average values of the above biochemical parameters in the HV group, the average value of LPO in erythrocytes in the MA group was significantly increased (P < 0.0001), while the average values of VC, VE and beta-CAR in plasma as well as those of SOD and CAT in erythrocytes in the MA group were significantly decreased (P < 0.0001). The analysis of bivariate correlations suggested that with the increase of the MDMA abuse dose and the MDMA abuse duration, the level of LPO in erythrocytes in the MA was increased (P < 0.0001), while the levels of VC, VE and beta-CAR in plasma as well as the activities of SOD and CAT in erythrocytes in the MA were decreased (P < 0.0001). CONCLUSION: The findings in this study suggest that MDMA abuse may cause oxidative stress and potential free radical damage to MA." [Abstract]

Wulf Dröge
Free Radicals in the Physiological Control of Cell Function
Physiol. Rev. 82: 47-95, 2002. [Full Text]

Pizzinat N, Copin N, Vindis C, Parini A, Cambon C.
Reactive oxygen species production by monoamine oxidases in intact cells.
Naunyn Schmiedebergs Arch Pharmacol 1999 May;359(5):428-31
"Monoamine oxidase (MAO) A and B are mitochondrial enzymes involved in the oxidative deamination of endogenous and exogenous amines. At present, the production of H2O2 by MAO in intact cells and its functional consequences in cell function have not been extensively investigated. The aim of this study was to define whether, in intact cells, the metabolism of small amounts of MAO substrates was able to induce a detectable H2O2 production. Hydrogen peroxide production was measured using a luminol-amplified chemiluminescence assay in three cell types, rat mesangial cells, rabbit proximal tubule cells and Hep-G2 cells, containing different MAO A/MAO B ratios. Our results showed that cell incubation with tyramine (50 micromol/l) led to a time-dependent H2O2 generation which was fully inhibited by MAO A (clorgyline and RO 41-1049) and MAO B (selegiline and RO 19-6327) inhibitors. The extent of inhibition of H2O2 production by selective inhibitors was in agreement with the amount of MAO isoforms expressed in each cell type, as determined by Western blot analysis and enzyme assay. Altogether, these findings show that, in a normal cell environment, MAO can be a source of reactive oxygen species which could have a functional impact on cell functions. In addition, we propose the luminol-amplified chemiluminescence assay as a rapid and sensitive procedure to characterize the monoamine oxidase isoforms and their regulation in intact cells." [Abstract]

Flanagan SW, Moseley PL, Buettner GR.
Increased flux of free radicals in cells subjected to hyperthermia: detection by electron paramagnetic resonance spin trapping.
FEBS Lett 1998 Jul 17;431(2):285-6
"It has been hypothesized that hyperthermia promotes oxygen-centered free radical formation in cells; however, to date there is no direct evidence of this heat-induced increase in oxygen free radical flux. Using electron paramagnetic resonance (EPR) spin trapping, we sought direct evidence for free radical generation during hyperthermia in intact, functioning cells. Rat intestinal epithelial cell monolayers were exposed to 45 degrees C for 20 min, after which the nitrone spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO) was added. Compared to control cells at 37 degrees C, heat-exposed cells had increased free radical EPR signals, consistent with the formation of DMPO/.OH (aN = aH = 14.9 G). These findings indicate that heat increases the flux of cellular free radicals and support the hypothesis that increased generation of oxygen-centered free radicals and the resultant oxidative stress may mediate in part, heat-induced cellular damage." [Abstract]

Che S, Johnson M, Hanson GR, Gibb JW.
Body temperature effect on methylenedioxymethamphetamine-induced acute decrease in tryptophan hydroxylase activity.
Eur J Pharmacol. 1995 Dec 7;293(4):447-53.
Brain tryptophan hydroxylase activity decreases within 15 min after a single administration of 3,4-methylenedioxymethamphetamine. In the present study, the effect of body temperature on this acute decrease of tryptophan hydroxylase activity was examined. 2 h after a single dose of 3,4-methylen