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effects of 3.4 methylenedioxymethamphetamine (MDMA) on mnemonic and executive measures and serotonergic neurotoxicity using interspecies effects scaling

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Date Issued:
2011
Summary:
3,4-methlenedioxymethamphetamine (MDMA), the main constituent of Ecstasy, is a ring-substituted amphetamine commonly abused in recreational users. High doses of MDMA determined by allometric scaling produce serotonin (5-HT) axon deneveration. Studies suggest that this interspecies scaling does not reflect human use. An 'effects' scale comparing similar behavioral and physiological effects between species has been postulated as more accurate for translational studies. Experiment 1 examined the effects of MDMA on serotonergic forebrain innervation using immunohistochemical labeling targeting the serotonin transporter protein (SERT). Experiments 2 and 3 examined low and high doses of MDMA on spatial memory, prefrontal functioning, and serotonergic neurotoxicity using 'effects' scaling. Long Evans rats were given MDMA regimens of: chronic low dose (daily injections of 1.5 mg/kg for 10 days); binge low dose (2 days of 4 x 1.5 mg/kg spaced 2 hours apart), binge high dose (2 x 7.5 mg/kg sp aced 2 hours apart). Acquisition, retention, and spatial reversal (SR) were measured in a water maze task. A 2.0 mg/kg MDMA drug challenge was then given prior to a serial spatial reversal (SSR) task to assess performance while under the effect of the drug. Attentional set shifting and behavioral flexibility were assessed in an intradimensional extradimensionl (IED) task using odor/texture discriminations. MDMA chronic and binge low doses did not impair water maze or IED performance and produced no reductions in SERT expression. MDMA binge high dose resulted in significant reductions of SERT density in the prefrontal cortex, striatum, cortical mantle, hippocampus, amygdala, and many thalamic nuclei. Despite prominent 5-HT denervation, water maze performance was unaffected. Selective impairment in behavioral flexibility on the IED test was found.
Title: The effects of 3.4 methylenedioxymethamphetamine (MDMA) on mnemonic and executive measures and serotonergic neurotoxicity using interspecies effects scaling.
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Name(s): Linley, Stephanie Brooke.
Charles E. Schmidt College of Science
Department of Psychology
Type of Resource: text
Genre: Electronic Thesis Or Dissertation
Issuance: monographic
Date Issued: 2011
Publisher: Florida Atlantic University
Physical Form: electronic
Extent: xxii, 313 p. : ill.
Language(s): English
Summary: 3,4-methlenedioxymethamphetamine (MDMA), the main constituent of Ecstasy, is a ring-substituted amphetamine commonly abused in recreational users. High doses of MDMA determined by allometric scaling produce serotonin (5-HT) axon deneveration. Studies suggest that this interspecies scaling does not reflect human use. An 'effects' scale comparing similar behavioral and physiological effects between species has been postulated as more accurate for translational studies. Experiment 1 examined the effects of MDMA on serotonergic forebrain innervation using immunohistochemical labeling targeting the serotonin transporter protein (SERT). Experiments 2 and 3 examined low and high doses of MDMA on spatial memory, prefrontal functioning, and serotonergic neurotoxicity using 'effects' scaling. Long Evans rats were given MDMA regimens of: chronic low dose (daily injections of 1.5 mg/kg for 10 days); binge low dose (2 days of 4 x 1.5 mg/kg spaced 2 hours apart), binge high dose (2 x 7.5 mg/kg sp aced 2 hours apart). Acquisition, retention, and spatial reversal (SR) were measured in a water maze task. A 2.0 mg/kg MDMA drug challenge was then given prior to a serial spatial reversal (SSR) task to assess performance while under the effect of the drug. Attentional set shifting and behavioral flexibility were assessed in an intradimensional extradimensionl (IED) task using odor/texture discriminations. MDMA chronic and binge low doses did not impair water maze or IED performance and produced no reductions in SERT expression. MDMA binge high dose resulted in significant reductions of SERT density in the prefrontal cortex, striatum, cortical mantle, hippocampus, amygdala, and many thalamic nuclei. Despite prominent 5-HT denervation, water maze performance was unaffected. Selective impairment in behavioral flexibility on the IED test was found.
Summary: This suggests that low doses of MDMA do not produce long-term deleterious effects. But, high doses of MDMA taken in 'binges' produces widespread loss of forebrain SERT fiber innervation and significant impairments in reversal learning, while leaving attentional set shifting and spatial navigation unscathed.
Identifier: 733047581 (oclc), 3171679 (digitool), FADT3171679 (IID), fau:3644 (fedora)
Note(s): by Stephanie Brooke Linley.
Thesis (Ph.D.)--Florida Atlantic University, 2011.
Includes bibliography.
Electronic reproduction. Boca Raton, Fla., 2011. Mode of access: World Wide Web.
Subject(s): MDMA (Drug)
Ecstasy (Drug) -- Psychological effect
Psychopharmacology
Methamphetamine abuse
Brain -- Effect of drugs on
Psychotropic drugs -- Side effects
Held by: FBoU FAUER
Persistent Link to This Record: http://purl.flvc.org/FAU/3171679
Use and Reproduction: http://rightsstatements.org/vocab/InC/1.0/
Host Institution: FAU