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[ Appendix 4 sec. 5 ] [ Index ] [ Appendix 4 sec 7 ]

Appendix 4: Bibliography Neurochemistry

Ali, S.F., Scallet, A.C., Holson, R.R., Newport, G.D. and Slikker Jr., W. Acute Administration of MDMA (Ecstasy): Neurochemical Changes Persist up to 120 Days in Rat Brain. Soc. Neurosci. Abstr. 13 904 (1987).

Rats were given 40 mg/Kg MDMA twice daily for 4 days. After 120 days, some regions of the brain (frontal cortex, hippocampus) still had serotonin depletion. There was fighting behaviour noted between rats during the dosing and for up to two weeks following it.

Ali, S.F., Scallet, A.C., Newport, G.D., Lipe, G.W., Holson, R.R. and Slikker Jr., W. Persistent Neurochemical and Structural Changes in Rat Brain after Oral Administration of MDMA. Res. Commun. Subst. Abuse 10 225-236 (1989).

Rats were administered short-term intense levels of MDMA orally, and then assayed for neurological changes after a period of four months. Changes were seen in the levels of both serotonin and 5-hydroxyindoleacetic acid, and neurohistological changes in the brain step were observed.

Anon. Long-term Effects of "Ecstasy": Study Finds Brain Cell Destruction. NIDA Notes 2 # 3. p. 7 (1987).

A short distillation of the present state of MDMA research in relationship to serotonin neurochemistry is presented.

Battaglia, G. and De Souza, E.B. Pharmacologic Profile of Amphetamine Derivatives at Various Brain Recognition Sites: Selective Effects on Serotonergic Systems. NIDA Research Monograph Series #94 240-258 (1989).

A review is presented of the affinities for a large number of substituted amphetamine derivatives for several serotonin receptors. An addition, a pharmacologic profile of binding affinities of MDMA at a number of recognition sites is tabulated.

Battaglia, G., Kuhar, M.J. and De Souza, E.B. MDA and MDMA (Ecstasy) Interactions with Brain Serotonin Receptors and Uptake Sites: In vitro Studies. Soc. Neurosciences Abs. 12 336.4 (1986).

The receptor site uptake of the optical isomers, as well as the racemate, of both MDA and MDMA were measured by separate, selective labelling with appropriate radioligands. The relationships between the isomers depended on whether uptake sites or receptors were involved, and differed at different locations in the brain.

Battaglia, G., Sharkey, J., Kuhar, M.J. and De Souza, E.B. Neuroanatomic Specificity and Time Course of Alterations in Rat Brain Serotoninergic Pathways Induced by MDMA (3,4- Methylenedioxymethamphetamine): Assessment Using Quantitative Autoradiography. Synapse 8 249-260 (1991).

A quantitative measure of the change in serotonin uptake sites as a consequence of MDMA exposure in rats was determined by the use of radio labelled Paroxetine. Changes as a function of time were noted in defined areas of the brain.

Battaglia, G., Yeh, S.Y. and De Souza, E.B. MDMA-Induced Neurotoxicity: Parameters of Degeneration and Recovery of Brain Serotonin Neurons. Pharmacol. Biochem. Behav. 29 269-274 (1988).

A number of parameters were studied to define the nature of the neurotoxic effect on serotonin axons and terminals. Both the size and frequency of drug administration resulted in a dose-dependent response. Regeneration of these neurons was also time dependent, returning to control levels in 12 months. Pretreatment with a serotonin uptake blocker (Citalopram) prevented the neurodegenerative effects of MDMA. The rat and guinea-pig brains were affected, whereas the mouse brain was not.

Battaglia, G., Yeh, S.Y., O'Hearn, E., Molliver, M.E., Kuhar, M.J. and De Souza, E.B. 3,4-Methylenedioxymethamphetamine and 3,4-Methylenedioxyamphetamine Destroy Serotonin Terminals in Rat Brain: Quantification of Neurodegeneration by Measurements of [3H] Paroxetine-Labelled Serotonin Uptake Sites. J. Pharm. Exptl. Therap. 242 911-916 (1987),

The effects of repeated administration of MDMA and MDA on the levels of rat brain monoamines and their metabolites are reported. Only the serotonin-related systems were found to be affected.

Battaglia, G., Zaczek, R. and De Souza, E. MDMA Effects in Brain: Pharmacologic Profile and Evidence of Neurotoxicity from Neurochemical and Autoradiographic Studies. The Clinical, Pharmacological and Neurotoxicological Effects of the Drug MDMA. Kluwer, New York. (1990) Ed: S.J. Peroutka.

A series of in vitro and in vivo studies of MDMA in rats has allowed a thorough mapping of the sites of MDMA-induced neurotoxicity.

Bird, M.P., Svendsen, C.N., Knapp, C., Hrbek, C.C., Bird, E.D. and Kornetsky, C. Evidence for Dopaminergic and Not Serotonergic Mediation of the Threshold Lowering Effects of MDMA on Rewarding Brain Stimulation. Soc. Neurosci. Abstr. 13, Part 3, p. 1323 (1987) No. 365.13.

An effort was made to determine the rewarding aspect of MDMA by a combination of brain electrodes and specific neurotransmitter inhibitors. It is felt that MDMA reinforcing values may be mediated by the dopamine D2 receptor rather than the serotonin 5-HT2 receptor.

Callaway, C.W., Nichols, D.E., Paulus, M.P. and Geyer, M.A. Serotonin Release is Responsible for the Locomotor Hyperactivity in Rats Induced by Derivatives of Amphetamine Related to MDMA. Serotonin: Molecular Biology, Receptors and Functional Effects, Birkh=E4user Verlag, Basel. J.R. Fozard and P.R. Saxena, Eds. (1991).

In rats MDMA produces locomotor hyperactivity, but the spatial pattern of locomotion differs qualitatively from the pattern of exploration produced by other psychostimulants.

Callaway, C.W., Rempel, N., Peng, R.Y. and Geyer, M.A. Serotonin 5-HT1-Like Receptors Mediate Hyperactivity in Rats Induced by 3,4-Methylenedioxymethamphetamine. Neuropsychopharm. 7 113-127 (1992).

This study was designed to evaluate the role of different serotonin (5-HT) receptor subtypes in mediating the effects of MDMA on a rat's exploration of a novel environment. This study indicates that S-MDMA produces a characteristic form of locomotor hyperactivity in rats that depends upon activation of 5-HT1-like receptors, possibly of the 5-HT1b subtype.

Champney, T.H. and Matthews, R.T. Pineal Serotonin is Resistant to Depletion by Serotonergic Neurotoxins in Rats. J. Pineal Res. 11 163-167 (1991).

A comparison between MDMA and p-chloroamphetamine (pCA) has been made in the rat with a view to neurotoxicity. Both compounds reduced serotonin levels in several brain areas, but neither affected the neurotransmitter levels in the pineal. This gland does not appear to have the serotonin re-uptake system that is thought to be necessary for MDMA or pCA induced neurotoxicity.

Champney, T.H., Golden, P.T. and Matthews, R.T. Reduction of Hypothalamic Serotonin Levels after Acute MDMA Administration. Soc. Neurosciences Absts. 12 101.6 (1986).

Cortical, hypothalamic, and pineal levels of catecholamines, serotonin and 5-HIAA were determined shortly following an acute exposure of rats to each of several doses of MDMA. Dose-dependent decreases of serotonin and 5-HIAA were noted in some but not other areas of the brain. The catecholamine levels were unchanged.

Commins, D.L., Vosmer, G., Virus, R.M., Woolverton, C.R., Schuster, C.R. and Seiden, L.S. Biochemical and Histological Evidence that Methylenedioxmethamphetamine (MDMA) is Toxic to Neurons in Rat Brain. J. Pharm. Exptl. Therap. 241 338-345 (1987).

MDMA was administered chronically to rats and guinea pigs , and the neurotransmitter levels were assayed in several portions of the brain. These levels were found to be related to dosage, and to the extent of exposure. Anatomical morbidity is carefully described.

Defrese, G.D.R. (+/-)-3,4-Methylenedioxymethamphetamine (MDMA): Extending the Debate Regarding Clinical Implications of its Neurotoxicity. Unpublished manuscript, Department of Pharmacology, U.C. Davis, (1990).

An experimental approach is proposed, using experimental animals, to evaluate the toxicological risks to man that might result from the reintroduction of MDMA into clinical practice.

De Souza, E.B. and Battaglia, G. Effects of MDMA and MDA on Brain Serotonin Neurons: Evidence from Neurochemical and Autoradiographic Studies. NIDA Research Monograph Series #94 196-222 (1989).

A series of studies with both MDMA and MDA demonstrate dose-dependent changes in the brain serotonin neurons, which can blocked by pretreatment with a serotonin uptake blocker.

DeSouza, E.B., Battaglia, G., Shu, Y.Y. and Kuhar, M.J. In Vitro and In Vivo Effects of MDA and MDMA (Ecstasy) on Brain Receptors and Uptake Sites: Evidence for Selective Neurotoxic Actions on Serotonin Terminals. Amer. Coll. of Neuropsychopharm. p. 207 (Dec. 8-12, 1986).

MDA and MDMA both showed a relatively high affinity for both 5-HT2 serotoninergic and alpha-2 adrenergic brain receptors, but low affinities for 5-HT1, and for the alpha-1 and beta adrenergic receptors, as well as for dopamine, muscarinic, and opiate receptors. Chronic administration of either drug decreases the number of 5-HT2 receptors in various brain locations.

Dornan, W.A., Katz, J.L. and Ricaurte, G.A. The Effects of Repeated Administration of MDMA on the Expression of Sexual Behaviour in the Male Rat. Pharmacol. Biochem. Behav. 39 813-816 (1991).

The repeated s.c administration of MDMA to rats produced a disruption of copulatory behaviour. These effects disappeared within a week.

Finnigan, K.T., Ricaurte, G.A., Ritchie, L.D., Irwin, I., Peroutka, S.J. and Langston, J.W. Orally Administered MDMA Causes a Long-term Depletion of Serotonin in Rat Brain. Brain Research 447 141-144 (1988).

The oral and sub-cutaneous routes of MDMA toxicity to rat serotonergic neurons are studied. Both routes lead to a dose dependent serotonin depletion.

Finnegan, K.T., Skratt, J.J., Irwin, I. and Langston, J.W. The N-Methyl-D-aspartate (NMDA) Receptor Antagonist, Dextrorphan, Prevents the Neurotoxic Effects of 3,4-Methylenedioxymethamphetamine (MDMA) in Rats. Neuroscience Letters 105 300-306 (1990).

In in vivo rat studies with various levels of MDMA and dextrorphan, the latter drug, a NMDA antagonist, completely prevented the serotonin-depleting action of MDMA.

Gaylor, D.W. and Slikker Jr, W. Risk Assessment for Neurotoxic Effects. Neurotoxicology 11 211-218 (1990).

A mathematical basis is presented for the estimation of risk as a function of dose, with drugs that are neurotoxic. An illustration is given for MDMA, based on rat and monkey data.

Gehlert, D.R. and Schmidt, C.J. Acute Administration of Methylenedioxymethamphetamine (MDMA) Results in a Persistent and Selective Increase in 5-HT1 Receptor Binding in Rat Brain. Pharmacologist 29 ABS-44 (1987).

Acute administration of MDMA in the rat showed an increase in serotonin binding in 24 hours. This occurred in several parts of the brain.

Glennon, R.A., Titeler, M., Lyon, R.A. and Youssif, M. MDMA ("Ecstasy"): Drug Discrimination and Brain Binding Properties. Soc. Neurosciences Abstrac ts 12 250.11 (1986).

In rats treated chronically with MDMA (trained to discriminate racemic MDMA from saline), radioligand binding studies were conducted with both serotonin and dopamine sites. The Ki values for both 5-HT1 and 5-HT2 receptors were highest for the "S" isomers of MDMA and MDA, with the racemate lower, and the "R" isomer yet lower. There was no particular affinity for the dopamine receptors studied.

Gold, L.H., Hubner, C.B. and Koob, G.F. The Role of Mesolimbic Dopamine in the Stimulant Action of MDMA. Soc. Neurosci. Abstr., Vol. 13, Part 3, p. 833 (1987) No. 234.13.

The administration of MDMA to rats may involve (like amphetamine) the release of dopamine. Test animals with lesions induced by 6-hydroxydopamine showed less motor activity in response to MDMA than control animals.

Gold, L.H., Hubner, C.B. and Koob, G.F. A Role for the Mesolimbic Dopamine System in the Psychostimulant Actions of MDMA. Psychopharmacology 99 40-47 (1989).

MDMA was evaluated in rats as a stimulant. Lesions induced with 6-hydroxydopamine modified the amphetamine-like responses seen, suggesting that the drug's action may involve the presynaptic release of dopamine in the region of the nucleus accumbens.

Gollamudi, R., Ali, S.F., Lipe, G., Newport, G., Webb, P., Lopez, M., Leakey, J.E.A., Kolta, M. and Slikker Jr., W. Influence of Inducers and Inhibitors on the Metabolism in vitro and Neurochemical Effects in vivo of MDMA. Neurotox. 10 455-466 (1989).

A number of experiments were conducted on rats, with the optical isomers of MDMA. The metabolic formation of MDA by N-demethylation, in vitro, was greater for the "S" isomer in the female than the male. This effect was lost with prior phenobarbital induction, and may be related to P-450 isozymes. In in vivo studies, either isomer appeared to be equally effective in depleting serotonin, but pretreatment studies suggest that an active metabolite other than MDA is formed.

Hanson, G.R., Sonsalla, P., Letter, A., Merchant, K.M., Johnson, M., Bush, L. and Gibb, J.W. Effects of Amphetamine Analogs on Central Nervous System Neuropeptide Systems. NIDA Research Monograph Series #94 259-269 (1989).

The effects of a number of substituted amphetamines on polypeptides associated with extrapyrimidal structures, have been observed. Both MDA and MDMA are included, and a discussion is presented of their possible contribution to both motor and mood changes related to drug-exposure.

Hashimoto, K. and Goromaru, T. Reduction of [3H] 6-Nitroquipazine-labelled 5-Hydroxytrypatmine Uptake Sites in Rat Brain by 3,4-Methylenedioxymethamphetamine. Fund. Clin. Pharmacol. 4 635-641 (1990).

The administration of the selective serotonin uptake inhibitor 6-nitroquipazine prevented the MDMA-induced reduction of serotonin and 5-hydroxyindoleacetic acid in rat brain. Tritiated 6-nitroquipazine was used as a probe for determining the receptor sites that recognized by MDMA.

Hashimoto, K. and Goromaru, T. Reduction of in vivo Binding of [3H]Paroxetine in Mouse Brain by 3,4-Methylenedioxymeth-amphetamine. Neuropharmacol. 29 633-639 (1990)

Pretreatment of a mouse with MDMA significantly modifies the radioactivity distribution of tritiated Paroxetine, a potent serotonin re-uptake inhibitor. The relative decrease of binding to hypothallimus and to cerebral cortex appears to be dose dependent.

Hashimoto, K. and Goromaru, T. Study of 3,4-Methylenedioxymethamphetamine-Induced Neurotoxicity in Rat Brain Using Specific In Vivo Binding of [3H] 6-Nitroquipazine. Res Comm. Subst. Abuse 13 191-201 (1992).

MDMA-induced neurotoxicity in the rat was studied employing 6-nitoquipazine binding. This radioligand appears to be well suited for studying neuropathology and neurochemical changes associated with brain serotonin.

Hashimoto, K., Maeda, H. and Goromaru, T. Antagonism of 3,4-Methylenedioxymethamphetamine-induced Neurotoxicity in Rat Brain by 1-Piperonylpiperazine. Eur. J. Pharmacol. - Envir. Toxicol. and Pharmacol. Section, 228 171-174 (1992).

Several serotonin uptake inhibitors were evaluated for their effects on MDMA-induced neurotoxicity. 6-Nitroquipazine, Paroxetine and 1-piperonylpiperazine were effective, but the immediate homologue of MDMA (N,alpha-dimethylpiperonylamine) was not.

Hekmatpanah, C.R., McKenna, D.J. and Peroutka, S.J. Reserpine does not Prevent 3,4-Methylenedioxyamphetamine-induced Neurotoxicity in the Rat. Neuroscience Letters (in press) 1989.

The administration of reserpine to rats, which reduces the brain monoamine stores in rats, did not prevent the degeneration of serotoninergic nerve terminals.

Hiramatsu, M. and Cho, A.K. Enantiomeric Differences in the Effects of 3,4-Methylenedioxymethamphetamine on Extracellular Monoamines and Metabolites in the Striatum of Freely-Moving Rats: An in vivo Microdialysis Study, Neuropharm. 29 269-275 (1990).

The effects of para-chloroamphetamine and of the optical isomers of MDMA on the extracellular levels of the metabolites of dopamine and of serotonin were determined by dialysis. The level of dopamine was increased, and that of its metabolites decreased, with p-CPA, (+) MDMA and (-) MDMA showing decreased potency. The serotonin metabolite 5-HIAA was also decreased, but there was no difference between the two optical isomers of MDMA in the production of this effect.

Hoffman, B.J., Mezey, E. and Brownstein, M.J. Cloning of a Serotonin Transporter Affected by Antidepressants. Science, 254 579-580 (1991).

A DNA clone for a serotonin transporter has been isolated. The cell uptake of the complimentary DNA resembles platelet serotonin uptake, and it is sensitive to antidepressants, amphetamine derivatives and cocaine. MDMA has an exceptionally high affinity.

Insel, T.R., Battaglia, G., Johannessen, J.N., Marra, S. and De Souza, E.B. 3,4-Methylenedioxymethamphetamine ("Ecstasy") Selectively Destroys Brain Serotonin Terminals in Rhesus Monkeys. J. Pharm. Exptl. Therap. 249 713-720 (1989).

In rhesus monkeys, the subacute administration of MDMA decreased both serotonin and 5-HIAA levels. At high levels there was also a decrease in the number of serotonin uptake sites (implying serotonin terminal destruction). There appears to be a considerable specificity as to brain region where these effects are expressed.

Johnson, M.P. and Nichols, D.E. Neurotoxin Effects of the Alpha-Ethyl Homologue of MDMA Following Subacute Administration. Pharmacol. Biochem. Behav. 33 105-108 (1989).

MBDB, the alpha-ethyl homologue of MDMA, was compared with MDMA in rats, as to potential neurotoxicity. There was a similar decrease in the number of observed serotonin binding sites but, unlike MDMA, there were no significant decreases in dopamine levels observed.

Johnson, M.P., and Nichols, D.E. Combined Administration of a Non-Neurotoxic 3,4-Methylenedioxymethamphetamine Analogue with Amphetamine Produces Serotonin Neurotoxicity in Rats. Neuropharmacology 30 819-822 (1991).

Two drugs have been studied in combination, in the rat. MMAI (5-methoxy-6-methyl-2-aminoindan) and S-(+)-amphetamine by themselves do not change any serotonin parameters in the rat. However, in combination, there was a central serotonin neurotoxicity induced. It appears that dopamine release plays a critical role in the serotonin neurotoxicity expression of substituted amphetamine derivatives.

Johnson, M.P., Conarty, P.F. and Nichols, D.E. [3H]Monoamine Releasing and Uptake Inhibition Properties of 3,4-Methylenedioxymethamphetamine and p-Chloroamphetamine Analogues. Eur. J. Pharmacol. 200 9-16 (1991).

A number of analogues of MDMA and of PCA were studied to determine their effectiveness in inhibiting the uptake of serotonin into synaptosomes, with or without pretreatment with reserpine. A valid relationship between the serotonin neurotoxic potential and the dopamine releasing ability of these compounds was noted.

Johnson, M.P., Hoffman, A.J. and Nichols, D.E. Effects of the Enantiomers of MDA, MDMA, and Related Analogues on [3H]Serotonin and [3H]Dopamine Release from Superfused Rat Brain Slices. Eur. J. Pharmacol. 132 269-276 (1986).

The study of a series of MDA homologues (MDA, MDMA, MBDB) showed a dramatic dependence between chain length and dopamine release. The longer the chain, the less the release. It is concluded that dopamine release plays a minor role in the human activity of these compounds.

Johnson, M.P., Huang, X. and Nichols, D.E. Serotonin Neurotoxicity in Rats After Combined Treatment with a Dopaminergic Agent Followed by a Nonneurotoxic 3,4-Methylenedioxymethamphetamine (MDMA) Analogue. Pharm. Biochem. Beh. 40 915-922 (1991).

Further evidence has been found linking dopamine to the long-term serotonergic neurotoxic effects of certain substituted amphetamines such as MDMA. Studies were conducted with MDAI (5,6-methylenedioxy-2-aminoindan (itself with a low neurotoxic liability) with several MAO inhibitors (clorgyline and deprenyl), with a dopamine uptake inhibitor led to no long term changes. Pretreatment with a dopamine releaser (S-amphetamine) did produce changes, however.

Johnson, M.P., Huang, X., Oberlender, R., Nash, J.F. and Nichols, D.E. Behavioural, Biochemical and Neurotoxicological Actions of the alpha-Ethyl Homologue of p-Chloroamphetamine. Eur. J. Pharmacol. 191 1-10 (1990).

The alpha-ethyl homologue of PCA was studied. The relationship of this compound (CAB) to PCA is that of the non-dopamine releasing MBDB (N-methyl-1-(1,3-benzodioxol-5-yl)-2-butanamine) to MDMA. Although CAB produces less disruption of the dopamine system, its effects on the serotonin system is similar to that of PCA.

Johnson, M., Elayan, I., Hanson, G.R., Foltz, R.L., Gibbs, J.W. and Lim, H.K. Effects of 3,4-Dihydroxymethamphetamine and 2,4,5-Trihydroxymethamphetamine, Two Metabolites of 3,4-Methylenedioxymethamphetamine, on Central Serotonergic and Dopaminergic Systems. J. Pharm. Exptl. Therap. 261 447-453 (1992).

Two metabolites of MDMA have been evaluated as to their contribution to neurotoxicity. The metabolite, 2,4,5- trihydroxymethamphetamine is toxic to both serotonin and dopamine nerve terminals, although it does not appear to explain the neurotoxic effects of MDMA.

Johnson, M., Hanson, G.R. and Gibb, J.W. Effects of Dopaminergic and Serotonergic Receptor Blockade on Neurochemical Changes Induced by Acute Administration of Methamphetamine and 3,4-Methylenedioxymethamphetamine. Neuropharm. 27 1089-1096 (1988).

By the use of specific neurorecptor ligands, the mechanisms of acute and long-term changes in the CNS from methamphetamine and MDMA exposure, have been investigated.

Johnson, M., Letter, A.A., Merchant, K., Hanson, G.R. and Gibb, J.W. Effects of 3,4-Methylenedioxyamphetamine and 3,4-Methylenedioxymethamphetamine Isomers on Central Serotonergic, Dopaminergic and Nigral Neurotensin Systems of the Rat. J. Pharm. Exptl. Therap. 244 977-982 (1988).

The difference of the isomers of MDA and MDMA in their ability to induce neurotransmitter changes and neurotensin immunoreactivity are reported. In general, the d-isomers of each were the more potent in affecting neurochemical systems.

Johnson, M., Stone, D.M., Bush, L.G., Hanson, G.R. and Gibb, J.W. Glucocorticoid and 3,4-Methylenedioxymethamphetamine (MDMA)-induced Neurotoxicity Eur. J. Pharmacol. 161 181 (1989).

A series of studies of the role of the glucocorticoids in the serotonin neurotoxicity of MDMA in rats has indicated some involvement in the hippocampal area.

Kalix, P. A Comparison of the Effects of Some Phenethylamines on the Release of Radioactivity from Isolated Rat Caudate Nucleus Prelabelled with 3H-Dopamine. Arzneim. Forsch. 36 1019-1021 (1986).

A number of phenethylamines were found to be able to release radioactive dopamine from prelabelled caudate nuclei. MDMA was not spectacular. The simplest unsubstituted amphetamine derivatives were the most effective.

Kalix, P., Yousif, M.Y. and Glennon, R.A. Differential Effects of the Enantiomers of Methylenedioxymeth-amphetamine (MDMA) on the Release of Radioactivity from (3H)Dopamine-Prelabeled Rat Striatum. Res. Commun. Subst. Abuse 9 45-52 (1988).

The S-isomer of MDMA (the more effective stimulant) is more effective than the R-isomer in releasing tritiated dopamine from rat striatum. It is about one sixth the potency of S-methamphetamine.

Kelland, M.D., Freeman,A.S. and Chiodo, L.A. (+/-)-3,4-Methylenedioxymethamphetamine- induced Changes in the Basal Activity and Pharmacological Responsiveness of Nigrostriatal Dopamine Neurons. Europ. J. Pharmacol. 169 11-21 (1989).

Studies of acute exposure of rats to MDMA showed an inhibition of the firing of dopamine neurons, and this effect is diminished following the depletion of either serotonin or dopamine. MDMA appears to exert direct functional effects on the nigrostriatal dopamine system.

Kleven, M.S., Woolverton, W.L. and Seiden, L.S. Evidence that both Intragastric and Subcutaneous Administration of Methylenedioxmethamphetamine (MDMA) Produce Serotonin Neurotoxicity in Rhesus Monkeys. Brain Research 488 121-125 (1989).

Subacute administration of MDMA to rhesus monkeys by both intragastric and subcutaneous routes was found to lead to depletion of both serotonin and 5-HIAA in various brain regions. Serotonin uptake sites were depleted following the oral route but not the subcutaneous route.

Kopajtic, T., Battaglia, G. and De Souza, E.B. A Pharmacologic Profile of MDA and MDMA on Brain Receptors and Uptake Sites. Soc. Neurosciences Abstrts. 12 336.1 (1986).

Both MDA and MDMA were studied at various brain recognition sites using radioligand binding techniques. The findings suggest that these drugs may express their effects at serotonin receptors or uptake sites and/or alpha-2 adrenergic receptors.

Logan, B.J., Laverty, R., Sanderson, W.D. and Yee, Y.B. Differences Between Rats and Mice in MDMA (Methylenedioxmethamphetamine) Neurotoxicity. Europ. J. Pharmacol. 152 227-234 (1988).

A single large administration of MDMA to the rat or the mouse caused only transient changes in serotonin, norepinephrine and dopamine levels (and those of their metabolites). Repeated administrations were required to establish long-lasting changes in the rat; the mouse remained relatively insensitive. It appears that the both the nature and the degree of neurotoxicity with MDMA is species-specific.

Lowe, M.T., Nash Jr., J.F. and Meltzer, H.Y. Selective Reduction of Striatal Type-II Glucocorticoid Receptors in Rats by 3,4-Methylenedioxymethamphetamine (MDMA). Eur. J. Pharmacol. 163 157-161 (1989).

A single large s.c. dose of MDMA to rats reduced, in addition to brain serotonin and 5-HIAA levels, the glucocorticoid levels in the striatum. No differences in the corticosterone levels were noted, however, suggesting that it may not play a role in the receptor reduction.

Lyon, R.A., Glennon, R.A. and Titeler, M. 3,4-Methylenedioxymethamphetamine (MDMA): Stereoselective Interactions at Brain 5-HT1 and 5-HT2 Receptors. Psychopharmacology 88 525-526 (1986).

The assay of the optical isomers of MDA and MDMA with isolated receptors of rat brains, suggested that MDMA does not work primarily through direct interaction with serotonin receptors.

Millan, M.J. and Colpaert, F.C. Methylenedioxymethamphetamine Induces Spontaneous Tail-flicks in the Rat via 5-HT1a Receptors. Eur. J. Pharmacol. 193 145-152 (1991).

MDMA, but not amphetamine, induced dose-dependent tail-flicks in restrained rats. These effects were blocked by serotonin uptake inhibitors, implicating these receptors in this response.

Mokler, D.J., Robinson, S.E. and Rosecrans, J.A. Differential Depletion of Brain 5-Hydroxytryptamine (5-HT) by (+/-) 3,4-Methylenedioxymethamphetamine (MDMA). Pharmacologist 29 ABS-273 (1987).

The sensitivity of specific brain areas for the 5-HT depleting effects of MDMA may relate to the metabolic activity of 5-HT neurones in that region.

Mokler, D.J., Robinson, S.E. and Rosecrans, J.A. (+/-) 3,4-Methylenedioxymethamphetamine (MDMA) Produces Long-term Reductions in Brain 5-Hydroxytryptamine in Rats. Eur. J. Pharmacol. 138 265-268 (1987).

Following chronic administration of MDMA to rats, both serotonin and 5-HIAA became depleted in the brain. It is suggested that MDMA can function as a neurotoxin.

Mokler, D.J., Robinson, S.E. and Rosecrans, J.A. A Comparison of the Effects of Repeated Doses of MDMA ("Ecstasy") on Biogenic Amine Levels in Adult and Neonate Rats. Soc. Neurosci. Abstr. 13No. 251.9 p.905 (1987).

MDMA was given to both adult and neonate rats in 10-40 mg/Kg doses over several days. The serotonin levels were decreased and the dopamine levels were significantly increased.

Molliver, M.E. Serotonergic Neural Systems: What Their Anatomic Organization Tells Us about Function. J. Clinical Psychopharm. 7 3S-23S (1987).

A review of the organization of the serotonin nervous system is presented. The findings associated with the neurotoxic effects of MDMA are used as instructive tools, and speculation is extended as to the role of these neurons in the generation of the affective state.

Molliver, M.E., Mamounas, L.A. and Wilson, M.A. Effects of Neurotoxic Amphetamines on Serotonergic Neurons: Immunocytochemical Studies. NIDA Research Monograph Series #94 270-305 (1989).

A highly detailed cytological mapping of the serotonin related structures in the rat brain, is presented. An immunocytological study, with anto-serotonin antibodies, has been made with several substituted amphetamines, including MDA and MDMA. The axon bodies are severely damaged, but the raphe cell bodies are spared. Some primate studies are discussed.

Molliver, M.E., O'Hearn, E., Battaglia, G. and De Souza, E.B. Direct Intracerebral Administration of MDA and MDMA Does Not Produce Serotonin Neurotoxicity. Soc. Neurosciences Abstrts. 12 336.3 (1986).

The microinjection of either MDA or MDMA directly in to the cerebral cortex resulted in no detectable cytotoxicity. This suggests that the neurotoxicity of both compounds may be due to some metabolite formed peripherally.

Monti, J.A., Beaton, J.M., Benington, F., Morin, R.D. and Christian, S.T. MDMA and MBDB Potentiate Phorbol Ester-Stimulated Catecholamine Release from PC-12 Cells. Soc. Neuroscience Abstrt. November 13-18, 1988.

The "S" isomer of both MDMA and MBDB are potent in stimulating catechol release from PC-12 cells. The norepinephrin and dopamine release was increased in the presence of phorbol dibenzoate. It is suggested that this release may be mediated by protein kinase-C.

Nader, M.A., Hoffmann, S.M. and Barrett, J.E. Behavioural Effects of (+/-) 3,4-Methylenedioxyamphetamine (MDA) and (+/-) 3,4-Methylenedioxymethamphetamine (MDMA) in the Pigeon: Interactions with Noradrenergic and Serotoninergic Systems. Psychopharmacology 98 183-188 (1989).

MDA, MDMA and MDE. were studied in a conditioned behaviour involving pigeons. MDA was the most potent of the three drugs. The use of serotonin and dopamine antagonists suggested that the actions of MDA and MDMA are mediated by different neurotransmitter systems.

Nash, J.F. and Yamamoto, B.K. Methamphetamine Neurotoxicity and Striatal Glutamate Release: Comparison to 3,4-Methylenedioxymethamphet- amine. Brain Research 581 237-243 (1992).

The neurotoxicity of methamphetamine and MDMA were compared by measuring the extracellular concentrations of several compounds by microdialysis in freely moving rats. The long term dopamine neurotoxicity from repeated methamphetamine administration is mediated, in part, by a delayed increase in extracellular glutamate. Repeated MDMA administration, at a dose that produced a long-term depletion of serotonin, had no effect on glutamate release.

Nash, J.F., Meltzer, H.Y. and Gudelsky, G.A. Effect of 3,4-Methylenedioxymethamphetamine on 3,4-Dihydroxyphenylalanine Accumulation in the Striatum and Nucleus Accumbers, J. Neurochem. 34 1062-1067 (1990).

The effect of MDMA on dopamine synthesis in rat brain was estimated by measuring DOPA accumulation following pretreatment with a decarboxylase inhibitor. It is suggested that dopamine plays a role in the serotonin depletion produced by MDMA.

Nash, J.F., Meltzer, H.Y. and Lowy, M.T. The Effect of Adrenalectomy on MDMA-Induced Dopamine Release in the Striatum as Measured by in vivo Microdialysis and Depletion of Serotonin. Res. Commun. Subst. Abuse 13 177-190 (1992).

The interaction of MDMA and corticosterone in neurotransmitter depletion was studied in adrenalectomized rats. There does not seem to be any significant role for corticosterone in the MDMA-induced depletionof serotonin and 5-hydroxyindoleacetic acid.

Nichols, D.E., Brewster, W.K., Johnson, M.P., Oberlender, R. and Riggs, R.M. Nonneurotoxic Tetralin and Indan Analogues of 3,4-Methylenedioxyamphetamine (MDA). J. Med. Chem. 33 703-710 (1990).

Four cyclic analogues of MDA were synthesized and evaluated pharmacologically. Two indanes and two tetralins were explored through discrimination studies relative to MDMA or LSD. They appear not to have serotonin neurotoxicity.

O'Hearn, E., Battaglia, G., De Souza, E.B., Kuhar, K.J. and Molliver, M.E. Systemic MDA and MDMA, Psychotropic Substituted Amphetamines, Produce Serotonin Neurotoxicity. Soc. Neurosciences Abstrts. 12 336.2 (1986).

Rats exposed chronically to either MDA or MDMA were found, on sacrifice, to have a reduced number of serotonin axon terminals. This was most evident in cerebral cortex, thalamus, olfactory bulb and striatum, but also occurred in other areas. This may be due to the binding of these drugs to the uptake sites. The serotonin cell bodies and the preterminal axons are spared.

O'Hearn, E., Battaglia, G., De Souza, E.B., Kuhar, M.J. and Molliver, M.E. Methylenedioxyamphetamine (MDA) and Methylenedioxymethamphetamine (MDMA) Cause Selective Ablation of the Serotoninergic Axon Terminals in Forebrain: Immunocytochemical Evidence for Neurotoxicity. J. Neuroscience 8 2788 (1988).

Following chronic administration of MDMA (or separately, MDA) to rats, there is observed a profound loss of serotoninergic neuron axons throughout the forebrain. Various regions of the brain are compared as to extent of damage. The catacholamine counterparts are not affected.

Pan, H.S. and Wang, R.Y. MDMA: Further Evidence that its Action in the Medial Prefrontal Cortex is Mediated by the Serotoninergic System. Brain Res. 539 332-336 (1991).

The administration of MDMA was found to suppress the firing rates of certain brain neurons in anaesthetized rats. The (+) isomer, but not the (-) isomer, mimics the racemate. These effects are blocked by the pretreatment with a serotonin uptake inhibitor.

Pan, H.S. and Wang, R.Y. The Action of (+/-)-MDMA on Medial Prefrontal Cortical Neurons is Mediated Through the Serotoninergic System. Brain Research 543 56-60 (1991).

Rats anaesthetized with chloral hydrate were given varying amounts of MDMA intravenously. Electrodes located in the brain showed decreased neuron excitement. Studies were extended to include pretreatment with para-chlorophenylalanine and alpha-methyl-paratyrosine. The action of MDMA apparently involves some endogenous serotonin release.

Paris, J.M. and Cunningham, K.A. Lack of Serotonin Neurotoxicity after Intraraphe Microinjection of (+) 3,4-Methylenedioxymethamphetamine (MDMA). Brain Res. Bull. 28 115-119 (1991).

Direct injection of MDMA into the dorsal and the median Raphe nuclei was followed, in two weeks, by assay for serotonin and catecholamine changes. No apparent neurotoxicity was found.

Peroutka, S.J. Relative Insensitivity of Mice to 3,4-Methylenedioxymethamphetamine (MDMA) Neurotoxocity. Res. Commun. Subst. Abuse 9 193-206 (1988).

The effects of MDMA were determined in mouse brain serotonin uptake sites using paroxetine binding as a measure. In distinction with rats, there were no effects that could be observed at dosages of up to 30 mg/Kg, administered chronically. These findings confirm that in the mouse, MDMA is not a neurotoxic agent.

Pierce, P.A. and Peroutka, S.J. Ring-substituted Amphetamine Interactions with Neurotransmitter Receptor Binding Sites in Human Cortex. Neuroscience Lett. 95 208-212 (1988).

Three psychotropic drugs, MDA, MDMA and MDE, were evaluated as to their affinities for the DOB binding site, as determined by the displacement of 77Br DOB as the labelled radioligand.

Piercey, M.F., Lum, J.T. and Palmer, J.R. Effects of MDMA ("ecstasy") on Firing Rates of Seroronergic, Dopaminergic, and Noradrenergic Neurons in the Rat. Brain Research 526 203-206 (1990).

MDMA is effective in the depression of serotonin neurons in the dorsal and median raphe. Noradrenalin neurons in the locus coeruleus were also depressed at moderate dosages, but dopamine neurons were unaffected.

Ricaurte G.A. and McCann, U.D. Neurotoxic Amphetamine Analogues: Effects in Monkeys and Implications for Humans. Ann. N. Y. Acad. Sci. 648 371-82 (1992)

A review is presented of the relationships between several amphetamine-related compounds (such as amphetamine, methamphetamine and MDMA) and changes in the neurotransmitter area. The changes seen in rodents are compared to those observed in non-human primates, and speculation is made concerning further extrapolation to humans. Research with these compounds should enhance our understanding of central monoaminergic systems in normal brain function, and their role in the pathophysiology of neuropsychiatric disorders

Ricaurte, G.A., Bryan, G., Strauss, L., Seiden, L. and Schuster, C. Hallucinogenic Amphetamine Selectively Destroys Brain Serotonin Nerve Terminals. Science 229 986-988 (1985).

MDA was studied and found to produce long lasting reductions in the level of serotonin, the number of serotonin uptake sites, and the concentration of 5-HIAA in the rat brain. It was suggested that these deficits were due to serotonin nerve terminal degeneration. This was the research report that had been submitted for publication at the time of the MDMA hearings, and that played a focal role in the emergency scheduling of MDMA.

Ricaurte, G.A., DeLanney, L.E., Irwin, I. and Langston, J.W. Toxic Effects of MDMA on Central Serotonergic Neurons in the Primate: Importance of Route and Frequency of Drug Application. Brain Research 446 165-169 (1988).

The toxicity of MDMA was studied in primates both by the oral and the subcutaneous routes, and in single and multiple doses. Multiple doses are more effective that single doses in depleting serotonin, and the s.c route is more effective than the oral route. However, a single, oral administration of MDMA still produces a long-lived depletion

Ricaurte, G.A., DeLanney, L.E., Wiener, S.G., Irwin, I. and Langston, J.W. 5-Hydroxyindoleacetic acid in Cerebrospinal Fluid Reflects Serotonergic Damage Induced by 3,4-Methylenedioxymethamphetamine in CNS of Non-human Primates. Brain Research 474 359-363 (1988).

The usefulness of 5-hydroxyindoleacetic acid in CSF as a marker for serotonergic damage induced by MDMA was evaluated in the monkey. Following toxic doses of MDMA, there was removal of CSF for the assay of this serotonin metabolite, followed by sacrifice of the animal for direct brain measurement. The resulting positive correlation supports this technique for the eventual search for MDMA-induced damage in humans.

Ricaurte, G.A., Finnegan, K.F., Nichols, D.E., DeLanney, L.E., Irwin, I. and Langston, J.W. 3,4-Methylenedioxymeth-amphetamine (MDE), a Novel Analogue of MDMA, Produces Long-lasting Depletion of Serotonin in the Rat Brain. Eur. J. Pharmacol. 137 265-268 (1987).

MDE was qualitatively similar to MDMA in the depletion of serotonin in rat brain, but was only one fourth as potent.

Ricaurte, G.A., Forno, L.S., Wilson, M.A., DeLanney, L.E., Irwin, I., Molliver, M.E. and Langston, J.W. (+/-) Methylenedioxymethamphetamine (MDMA) Exerts Toxic Effects on Central Serotonergic Neurons in Primates. Soc. Neurosci. Abstr. 13 No. 251.8 p. 905 (1987).

MDMA was given s.q. twice daily for four days to monkeys, at 2.5, 3.75 and 5 mg/Kg. Post-mortem brain analyses showed serotonin reduction (90%) and axon damage. Some was described as "striking" and involved morphological changes.

Ricaurte, G.A., Forno, L.S., Wilson, M.A., DeLanney, L.E., Irwin, I., Moliver, M.E. and Langston, J.W. (+/-) 3,4-Methylenedioxymethamphetamine Selectively Damages Central Serotonergic Neurons in Nonhuman Primates. J. Am. Med. Assn. 260 51-55 (1988).

The parenteral administration (subcutaneous, twice daily for four days) of MDMA to monkeys of three species produced both brain serotonin depletion and accompanying neuron damage upon autopsy following a two-week waiting period. Considerable microscopic detail is given. The evidence presented could imply, but does not established, that there may be actual neuron cell death. The humanpattern of use is oral rather than parenteral, but a warning for prudence is advanced for the human use of either MDMA or (the neurotoxicologically similar drug) Fenfluramine.

Ricaurte, G.A., Marletto, A.L., Katz, J.L. and Marletto, M.B. Lasting Effects of (+/-)-3,4-Methylenedioxymethamphetamine (MDMA) on Ventral Serotonergic Neurons in Nonhuman Primates: Neurochemical Observations. J. Pharm. Exptl. Therap. 261 616-622 (1992).

A study was made of the duration of the neurotoxic effects of MDMA on squirrel monkeys (5 mg/day, twice daily, for 4 days) as a function of time, from 2 weeks to a year and a half. A control blank was used. Serotonin deficits persisted, suggesting that MDMA produces lasting effects.

Scallet, A.C., Ali, S.F., Holson, R.R., Lipe, G.W. and Slikker Jr., W. Neurohistological Effects 120 Days after Oral Ecstasy (MDMA): Multiple Antigen Immunohistochemistry and Silver Degeneration Staining. Soc. Neurosci. Abstr. 13, Part 3 No. 251.6, p. 904 (1987).

Both silver degeneration procedures (Fink-Heimer) and immunohistochemical techniques have been applied to MDMA-treated rats long after dosing. There are indications of regional differences in recovery, and that some changes may be irreversible.

Scheffel, U. and Ricaurte, G.A., Paroxetine as an in vivo Indicator of 3,4-Methylenedioxymethamphetamine Neurotoxicity: A Presynaptic Serotonergic Positron Emission Tomography Ligand? Brain Research 527 89-95 (1990).

The value of Paroxetine as an indicator of serotonergic nerve axon damage was demonstrated by the effectiveness of 5,7-dihydroxytryptamine in decreasing specific binding. MDMA treatment of rats gave similar reduction in labelled Paroxetine binding.

Scheffel, U., Lever, J.R., Stathis, M., Ricaurte, G.A. Repeated Administration of MDMA Causes Transient Down-regulation of Serotonin 5-HT2 Receptors. Neuropharm. 31 881-893 (1992).

The repeated administration of MDMA to rats causes a down regulation of serotonin receptors ion the brain of the rat. N-methyl-2-iodolysergic acid diethylamide is a suitable ligand for the labelling of these receptors in vitro and in vivo..

Schlechter, M.D. Serotonergic-Dopaminergic Mediation of 3,4-Methylenedioxymethamphetamine (MDMA, "Ecstasy"). Pharmacol. Biochem. and Behav. 31 817-824 (1989).

The discriminative stimuli properties of MDMA in rats, were studied to explore the serotinergic, as contrasted to the dopaminergic, nature of the drug's action. In the early part of the behavioural responses, the effects appear to be exclusively serotinergic, but in the latter period, there are some believable dominergic actions.

Schmidt, C.J. Acute Administration of Methylenedioxymethamphetamine: Comparison with the Neurochemical Effects of its N-Desmethyl and N-Ethyl Analogs. Eur. J. Pharmacol. 136 81-88 (1987).

MDMA (and its two immediate homologues, MDMA and MDE) were studied in the serotoninergic systems in the rat brain. There was depletion of cortical serotonin which in the case of MDMA appeared to persist after at least a week.

Schmidt, C.J. Neurotoxicity of the Psychedelic Amphetamine, Methylenedioxymethamphetamine. J. Pharm. Exptl. Therap. 240 1-7 (1987).

Evidence is presented that MDMA has a complex effect on rat serotonergic neurons, that results in a neurotoxic change at the nerve terminals. A parallel is drawn to the neurotoxin para-chloroamphetamine.

Schmidt, C.J., Acute and Long-term Neurochemical Effects of Methylenedioxmethamphetamine in the Rat. NIDA Research Monograph Series #94 179-195 (1989).

An analysis of short and long-term brain serotonin-related changes was made, and interpreted. Comparisons were made to PCA, methamphetamine and Fenfluramine.

Schmidt, C.J. and Kehne, J.H. Neurotoxicity of MDMA: Neurochemical Effects. Ann. N. Y. Acad. Sci. 600 665-681 (1990).

A review of the experimental findings involving both serotonin and dopamine in the neurotoxic action of MDMA. The actual mechanism of action remains unknown.

Schmidt, C.J. and Lovenberg, W. (+/-)Methylenedioxymethamphetamine (MDMA): A Potentially Neurotoxic Amphetamine Analogue. Fed. Proc. 45 1059 (#5264) April 13-18, (1986). Note paper below, Schmidt et al., with this same title.

Rats were administered MDMA s.c. at various doses and sacrificed at three hours. Brain concentrations of dopamine and serotonin, and their major metabolites were determined. The serotonin concentrations were reduced in a dose-dependent manner. Co-administration of a serotonin uptake inhibitor, Citalopram, blocked the MDMA-induced decline in striatal serotonin concentrations suggesting a mechanism similar to that of the known serotonergic neurotoxin p-chloroamphetamine.

Schmidt, C.J. and Lovenberg, W. Further Studies on the Neurochemical Effects of 4,5-Methylenedioxymethamphetamine and Related Analogues. Soc. Neurosciences Abstrts. 12 169.5 (1986).

The racemate and optical isomers of MDMA produced depletion of cortical and striatal serotonin. The (+) isomer was the more effective material. MDA was similar to MDMA, but effects produced by the N-ethyl homologue (MDE) were reversed in a week. Whereas all three drugs caused an acute decrease in serotonin concentration, only MDA and MDMA reduced the uptake of tritiated serotonin at the dosages studied (20 mg/Kg).

Schmidt, C.J. and Taylor, V.L. Direct Central Effects of Acute Methylenedioxymethamphetamine on Serotonergic Neurons. Eur. J. Pharmacol. 156 121-131 (1988).

The optical isomers of MDMA were studied separately in the rat as to their effects on loss of brain tryptophan hydroxylase. This appeared to precede the drop of serotonin concentration in the same areas. Injections of MDMA directly into the brain had no effect on either measure.

Schmidt, C.J. and Taylor, V.L. Neurochemical Effects of Methylenedioxymethamphetamine in the Rat: Acute versus Long-term Changes. The Clinical, Pharmacological and Neurotoxicological Effects of the Drug MDMA. Kluwer, New York. (1990) Ed: S.J. Peroutka

A study is presented describing the changes in the brains of rats which had been administered MDMA. It is felt that the release of dopamine is a prerequisite for the neurotoxic effects seen.

Schmidt, C.J., Abbate, G.M., Black, C.K. and Taylor, V.L. Selective 5-Hydroxytryptamine-2 Receptor Antagonists Protect against the Neurotoxicity of Methylendioxymethamphetamine in Rats. J. Pharm. Exptl. Therap. 255 478-483 (1990).

The characteristic serotonin deficits produced in rats by MDMA were prevented by the simultaneous administration of serotonin antagonists such as Ritanserin. The action of such drugs may involve dopamine.

Schmidt, C.J., Black, C.K., Abbate, G.M. and Taylor, V.L. Methylenedioxymethamphetamine-induced Hyperthermia and Neurotoxicity are Independently Mediated by 5-HT2 Receptors. Brain Research 529 85-90 (1990).

In rats, MDMA produces a hyperthermia which can be partially antagonised, as can the induced neurotoxicity, by the administration of a serotonin antagonist.

Schmidt, C.J., Black, C.K., Abbate, G.M. and Taylor, V.L Chloral Hydrate Anesthesia Antagonizes the Neurotoxicity of 3,4-Methylenedioxymethamphetamine. Eur. J. Pharmacol. 191 213-216 (1990).

When chloral anesthesia is administered to rats that have been administered MDMA, there is an interference with the induced neurotoxicity. This may be due to some role played by dopamine release.

Schmidt, C.J., Black, C.K. and Taylor, V.L. Antagonism of the Neurotoxicity due to a Single Administration of Methylenedioxyamphetamine. Eur. J. Pharmacol. 181 59-70 (1990).

A complex series of experiments in the rat investigating MDMA has suggested that the release of both dopamine and serotonin are implicated in the observed neurotoxicity of MDMA.

Schmidt, C.J., Black, C.K. and Taylor, V.L. L-DOPA Potentiation of the Serotoninergic Deficits Due to a Single Administration of 3,4-Methylenedioxymethamphetamine, p-Chloroamphetamine or Methamphetamine to Rats. Eur. J. Pharmacol. 203 41-49 (1991).

The role of dopamine in the serotoninergic neurotoxicity of MDMA, PCA, methamphetamine, MDE, and Fenfluramine was assessed by their co-administration with L-DOPA. The findings reported support a role for dopamine release in the toxicity of the first three of these drugs.

Schmidt,C.J., Levin, J.A. and Loverberg, W. In Vitro and In Vivo Neurochemical Effects of Methylenedioxymethamphetamine on Striatal Monoaminergic Systems in the Rat Brain, Biochem. Pharmacol. 36 747-755 (1987).

This study compares the effects of MDMA and MDA on neurotransmitter release in vitro and the (+) isomer is the more effective. The (+) isomer is also the more effective in vivo.

Schmidt, C.J., Vicki, L., Taylor, G.M. and Nieduzak, T.R. 5-HT-2 Antagonist Stereoselectivly Prevents the Neurotoxicity of 3,4-Methylenedioxymethamphetamine by Blocking the Acute Stimulation of Dopamine Synthesis: Reversal by L-DOPA. J. Pharm. Exptl. Therap. 256 230-235 (1991).

The effects of the optical isomers of a serotonin antagonist (one active, the other inactive) on the interaction of MDMA with both the dopaminergic and the serotoninergic systems of the male rat were studied. The protective effects against forebrain serotonin deficit that was observed, was reversed by the administration of L-DOPA.

Schmidt, C.J., Wu, L. and Lovenberg, W. Methylenedioxymethamphetet-amine: A Potentially Neurotoxic Amphetamine Analogue. Eur. J. Pharmacol. 124 175-178 (1986).

Acute administration of MDMA to rats provide selective and long lasting serotonin and 5-HIAA depletion, similar to that produced by p-chlorophenylalanine. There was an elevation of neostriatal dopamine as well as it primary metabolite homovanillic acid. A typewritten draft of this paper was presented to the DEA in conjunction with the legal hearings held concerning the scheduling of MDMA.

Seiden, L.S. Report of Preliminary Results on MDMA. Document entered into evidence Re: MDMA Scheduling Docket No. 84-48, U.S. Department of Justice, Drug Enforcement Administration, October 16, 1985.

Rats were treated both acutely and chronically with MDMA, and the study of the decrease of serotonin receptors and the interpretation of neurological staining indicated a neurotoxicity similar to, but less dramatic than, that seen with MDA.

Slikker, Jr., W. and Gaylor, D.W. Biologically-Based Dose-Response Model for Neurotoxicity Risk Assessment. Korean J. Toxicol. 6 205-213 (1990).

A discussion of a model of risk assessment of neurotoxicity is presented, illustrated by published experimental details from MDMA in experimental rats.

Slikker Jr., W., Ali, S.F., Scallet, A.C. and Frith, C.H. Methylenedioxymethamphetamine (MDMA) Produces Long Lasting Alterations in the Serotonergic System of Rat Brain. Soc. Neurosciences Abstrts. 12 101.7 (1986).

The chronic treatment of rats with MDMA (orally) produced decreased levels of serotonin and 5-HIAA. At high dose levels there was a temporary decrease in homovanillic acid (HVA) but no change in dopamine levels.

Slikker Jr., W., Ali, S.F., Scallet, A.C., Firth, C.H., Newport, G.D. and Bailey, J.R. Neurochemical and Neurohistological Alterations in the Rat and Monkey Produced by Orally Administered Methylenedioxmethamphetamine (MDMA). Toxicol Appl. Pharmacol. 94 448-457 (1988).

A complete neurohistochemical study of chronically administered MDMA, orally, to either rats of monkeys, showed extensive indications of serotonin neuron involvement, but no changes in with either dopamine or its primary metabolites.

Slikker Jr., W., Holson, R.R., Ali, S.F., Kolta, M.G., Paule, M.G., Scallet, A.C., McMillan, D.E., Bailey, J.R., Hong, J.S. and Scalzo, F.M. Behavioural and Neurochemical Effects of Orally Administered MDMA in the Rodent and Nonhuman Primate. Neurotox. 10 529-542 (1989).

MDMA was compared to p-chloroamphetamine (PCA) in rats following short-term chronic oral administration. Observations were made on behavioural effects and on neurochemical changes. Both compounds showed the "serotonin motor syndrome" but these markers were not persistent, although the brain serotonin level decreases were maintained with time. Similar decreases were seen in monkeys, but there was no behavioural modification evident.

Spanos, L.J. and Yamamoto, B.K. Methylenedioxymethamphetamine (MDMA)-induced Efflux of Dopamine and Serotonin in Rat Nucleus Accumbens. Soc. of Neurosciences Abstr. 12 p. 609 (#169.6) (1986).

Following MDMA administration to rats, the efflux of dopamine was decreased but then it quickly recovered. Serotonin depletion does not recover even after 2 hours, thus MDMA may be neurotoxic.

Steele, T.D., Brewster, W.K., Johnson, M.P., Nichols, D.E. and Yim, G.K.W. Assessment of the Role of alpha-Methylepinine in the Neurotoxicity of MDMA. Pharm. Biochem. Behav. 38 345-351 (1991).

The catachol metabolite of MDMA, alpha-methylepinine, was evaluated as a potential contributor to the neurotoxicity of MDMA. It was formed metabolicially, and also assayed directly. No relationship to biogenic amines was observed, and it appears not to be responsible for the observed MDMA effects.

Stone, D.M., Hanson, G.R. and Gibb, J.W. Does Dopamine Play a Role in the Serotonergic "Neurotoxicity" Induced by 3,4-Methylenedioxymethamphetamine (MDMA)? Soc. Neurosciences Abstrt. 12 169.4 (1986).

The possibility that the negative serotonin effects of MDMA might be mediated by dopamine was investigated. Studies involving dopamine synthesis inhibitors and antagonists suggest less involvement of dopamine than is seen with methamphetamine.

Stone, D.M., Hanson, G.R. and Gibb, J.W. Differences in the Central Serotonergic Effects of Methylenedioxymethamphetamine (MDMA) in Mice and Rats. Neuropharm. 26 1657-1661 (1987).

A number of studies as to the brain serotonin responses to MDMA (in rats) suggest that the duration of exposure might be an important factor in the estimation of toxic effects. Mice are shown to be less susceptible to MDMA, neurotoxicologically, than rats.

Stone, D.M., Merchant, K.M., Hanson, G.R. and Gibb, J.W. Immediate and Long Term Effects of 3,4-Methylenedioxymethamphetamine on Serotonin Pathways in Brain of Rat. Neuropharmacology 26 1677-1683 (1987).

The time course for the decrease of markers of central serotonin function in the rat is reported. Changes were observed at 15 minutes following a 10 mg/Kg s.c. injection, and much recovery was observed at the 2 week point. Following multiple dose administration of MDMA, significant serotonin changes were still evident after 110 days.

Stone, D.M., Stahl, D.C., Hanson, G.R. and Gibb, J.W. The Effects of 3,4-Methylenedioxymethamphetamine (MDMA) and 3,4-Methylenedioxyamphetamine (MDA) on Monoaminergic Systems in the Rat Brain. Eur. J. Pharmacol. 128 41-48 (1986).

Single or multiple doses of either MDMA or MDA caused marked reduction in both serotonin and 5-HIAA, as well as in the associated enzyme tryptophane hydroxylase (TPH). Single injections elevated striatal dopamine concentrations, although after repeated injections, these values became normal. Striatal tyrosine hydroxylase (TH) was not changed.

St. Omer, V.E.V., Ali, S.F., Holson, R.R., Duhart, H.M., Scalzo, F.M. and Slikker, W. Behavioural and Neurochemical Effects of Prenatal Methylenedioxymethamphetamine (MDMA) Exposure in Rats. Neurotox. Teratol. 13 13-20 (1991).

Pregnant rats were treated repeatedly with MDMA. The progeny were completely normal as to litter size, birth weight, physical appearance, maturation parameters, and other measures of behaviour. No neurological deficit could be observed, although the mother showed some decrease in weight gain, and decreases in brain levels of serotonin at selected locations.

Takeda, H., Gazzara, R.A., Howard, S.G. and Cho, A.K. Effects of Methylenedioxymethamphetamine (MDMA) on Dopamine (DA) and Serotonin (5-HT) Efflux in the Rat Neostriatum. Fed. Proc. 45 1059 (#5266) April 13-18, 1986.

Employing electrodes implanted in the neostriatum of anaesthetized rats, the MDMA-induced efflux of dopamine and serotonin was measured. The serotonin efflux was significantly increased by MDMA, and had returned to normal by three hours. The dopamine efflux increased slightly, and then dropped below normal. MDA decreased the dopamine efflux.

Trulson, T.J. and Trulson, M.E. 3,4-Methylenedioxymethamphetamine (MDMA) Suppresses Serotonergic Dorsal Raphe Neuronal Activity in Freely Moving Cats and in Midbrain Slices in vitro. Soc. Neurosci. Abstr. Vol. 13, Part 3, p. 905 (1987) No. 251.7.

A study of the decrease of brain serotonin levels in cats given 0.25-5.0 mg/Kg MDMA is reported. Pretreatment with p-chloroamphetamine greatly attenuated the suppressant action of MDMA, and it is suggested that the action of the two drugs is similar.

Wagner, J. and Peroutka, S.J., Neurochemistry and Neurotoxicity of Substituted Amphetamines, Neuropsychopharm. 3 219-220 (1990).

MDMA was compared with Fenfluramine as a depletor of serotonergic nerve terminals, as determined by the reduction of the density of paroxetine binding sites in rat's brains. Single dosages of 30 mg/Kg and 10 mg/Kg were required of the two drugs, respectively, to achieve significant changes.

Whitaker-Azmitia, P.M. and Azmitia, E.C. A Tissue Culture Model of MDMA Toxicity. The Clinical, Pharmacological and Neurotoxicological Effects of the Drug MDMA. Kluwer, New York. (1990) Ed: S.J. Peroutka

A procedure is described for studying MDMA toxicity employing tissue cultures prepared from fetal rat brains. The similarities and the differences observed between this technique and the more common in vivo techniques, are discussed.

Wilson, M.A., Ricaurte, G.A. and Molliver, M.E. The Psychotropic Drug 3,4-Methylenedioxymethamphetamine (MDMA) Destroys Serotonergic Axons in Primate Forebrain: Regional and Laminar Differences in Vulnerability. Soc. Neurosci. Abstr., Vol. 13, Part 3, No. 251.8 p. 905 (1987).

The monkey shows a striking brain loss of serotonin terminals following exposure to MDMA twice daily for 4 days at 5 mg/Kg. The distribution and extent of this damage is reported.

Wilson, M.A., Ricaurte, G.A. and Molliver, M.E. Distinct Morphologic Classes of Serotoninergic Axons in Primates Exhibit Differential Vulnerability to the Psychotropic Drug 3,4-Methylenedioxymethamphetamine. Neuroscience 28 121 (1989).

An exacting study is presented describing the morphological changes seen in the serotoninergic axons in the monkey's brain following MDMA exposure.

Woolverton, W.L., Virus, R.M., Kamien, J.B., Nencini, P., Johanson, C.E., Seiden, L.S. and Schuster, C.R. Behavioural and Neurotoxic Effects of MDMA and MDA. Amer. Coll. Neuropsychopharm. Abstrts. p. 173 (1985).

In behavioural studies in rats and monkeys trained to distinguish amphetamine from saline, MDMA mimicked amphetamine. With chronic administration, MDMA caused a degeneration of serotonin uptake sites, but no change in affinity of the undamaged sites. These results were similar to, but greater than, those seen with MDA.

Yamamoto, B.K. and Spanos, L.J. The Acute Effects of Methylenedioxymethamphetamine on Dopamine Release in the Awake-behaving Rat. Eur. J. Pharmacol. 148 195-204 (1988).

The effects of MDMA on the caudate and nucleus accumbens dopamine release and metabolism were studied by in vivo voltammetry and HPLC with electrochemical detection. There was a dose-dependent dopamine release observed in both regions by both measures.

Yeh, S.Y. Lack of Protective Effect of Chlorpromazine on 3,4-Methylenedioxymethamphetamine Induced Neurotoxicity on Brain Serotonin Neurons in Rats. Res. Commun. Subst. Abuse 11 167-174 (1990).

Studies involving the administration of MDMA with or without chlorpromazine suggests have suggested that chlorpromazine does not protect MDMA-induced depletion of serotonin in rats.

Yeh, S.Y. and Hsu, F-L Neurotoxicity of Metabolites of MDA and MDMA (Ecstasy) in the Rat. Soc. Neurosci. Abstr., Vol. 13, Part 3, p. 906 (1987) No. 251.11.

MDA, MDMA, and a number of potential metabolites (4-OH-3-OMe- amphetamine, alpha-methyldopamine, alpha-methylnorepinephrine) were studied in the rat, and the serotonin decreases measured. These metabolites have a lower neurotoxicity than the parent compound.

Zaczek, R., Culp, S. and De Souza, E.B. Intrasynaptosomal Sequestration of [3H]Amphetamine and [3H]Methylenedioxyamphetamine: Characterization Suggests the Presence of a Factor Responsible for Maintaining Sequestration. J. Neurochem. 54 195-204 (1990).

The incorporation of tritiated amphetamine, MDA and MDMA into rat brain synaptosomes was studied. The observed dynamics is discussed in relationship to the mechanism of action of amphetamine-induced monoamine release.

Zaczek, R., Hurt, S., Culp, S. and DeSouza, E.B. Characterization of Brain Interactions with Methylenedioxyamphetamine and Methylenedioxymethamphetamine. NIDA Research Monograph Series #94 223-239 (1989).

Brain recognition sites have been described for labelled MDA and MDMA, and similarities between these and the corresponding amphetamine sites are noted.

Zhao, Z., Castagnoli Jr., N, Ricaurte, G.A., Steele, T. and Martello, M. Synthesis and Neurotoxicological Evaluation of Putative Metabolites of the Serotoninergic Neurotoxin 2-(Methylamino)-1-[3,4-(methylenedioxy)phenyl]propane [(Methylenedioxy)methamphetamine]. Chem. Res. Toxicol. 5 89-94 (1992).

A number of potential toxic metabolites of MDMA were synthesized and assayed as neurotoxins. One of these, 2,4,5-trihydroxymethamphetamine, was found to deplete both dopamine and serotonin.