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Young JW, Geyer MA, Halberstadt AL, van Enkhuizen J, Minassian A, Khan A, Perry W, Eyler LT. Convergent neural substrates of inattention in bipolar disorder patients and dopamine transporter-deficient mice using the 5-choice CPT. Bipolar Disord 2020; 22:46-58. [PMID: 31025493 PMCID: PMC6815232 DOI: 10.1111/bdi.12786] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
OBJECTIVES Bipolar disorder (BD) is a debilitating psychiatric illness affecting 2%-5% of the population. Although mania is the cardinal feature of BD, inattention and related cognitive dysfunction are observed across all stages. Since cognitive dysfunction confers poor functional outcome in patients, understanding the relevant neural mechanisms remains key to developing novel-targeted therapeutics. METHODS The 5-choice continuous performance test (5C-CPT) is a mouse and fMRI-compatible human attentional task, requiring responding to target stimuli while inhibiting responding to nontarget stimuli, as in clinical CPTs. This task was used to delineate systems-level neural deficits in BD contributing to inattentive performance in human subjects with BD as well as mouse models with either parietal cortex (PC) lesions or reduced dopamine transporter (DAT) expression. RESULTS Mania BD participants exhibited severe 5C-CPT impairment. Euthymic BD patients exhibited modestly impaired 5C-CPT. High impulsivity BD subjects exhibited reduced PC activation during target and nontarget responding compared with healthy participants. In mice, bilateral PC lesions impaired both target and nontarget responding. In the DAT knockdown mouse model of BD mania, knockdown mice exhibited severely impaired 5C-CPT performance versus wildtype littermates. CONCLUSIONS These data support the role of the PC in inattention in BD-specifically regarding identifying the appropriate response to target vs nontarget stimuli. Moreover, the findings indicate that severely reduced DAT function/hyperdopaminergia recreates the attentional deficits observed in BD mania patients. Determining the contribution of DAT in the PC to attention may provide a future target for treatment development.
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Affiliation(s)
- Jared W. Young
- Department of Psychiatry, University of California San Diego, 9500 Gilman Drive MC 0804, La Jolla, CA 92093-0804
- Desert-Pacific Mental Illness Research Education and Clinical Center, VA San Diego Healthcare System, San Diego, CA
| | - Mark A. Geyer
- Department of Psychiatry, University of California San Diego, 9500 Gilman Drive MC 0804, La Jolla, CA 92093-0804
- Desert-Pacific Mental Illness Research Education and Clinical Center, VA San Diego Healthcare System, San Diego, CA
| | - Adam L. Halberstadt
- Department of Psychiatry, University of California San Diego, 9500 Gilman Drive MC 0804, La Jolla, CA 92093-0804
| | - Jordy van Enkhuizen
- Department of Psychiatry, University of California San Diego, 9500 Gilman Drive MC 0804, La Jolla, CA 92093-0804
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands
| | - Arpi Minassian
- Department of Psychiatry, University of California San Diego, 9500 Gilman Drive MC 0804, La Jolla, CA 92093-0804
| | - Asma Khan
- Department of Psychiatry, University of California San Diego, 9500 Gilman Drive MC 0804, La Jolla, CA 92093-0804
| | - William Perry
- Department of Psychiatry, University of California San Diego, 9500 Gilman Drive MC 0804, La Jolla, CA 92093-0804
| | - Lisa T. Eyler
- Department of Psychiatry, University of California San Diego, 9500 Gilman Drive MC 0804, La Jolla, CA 92093-0804
- Desert-Pacific Mental Illness Research Education and Clinical Center, VA San Diego Healthcare System, San Diego, CA
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Brain Cortical and Hippocampal Dopamine: A New Mechanistic Approach for Eurycoma longifolia Well-Known Aphrodisiac Activity and Its Chemical Characterization. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2019; 2019:7543460. [PMID: 31275418 PMCID: PMC6582863 DOI: 10.1155/2019/7543460] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 04/06/2019] [Accepted: 05/05/2019] [Indexed: 12/15/2022]
Abstract
Eurycoma longifolia Jack (Fam.: Simaroubaceae), known as Tongkat Ali (TA), has been known as a symbol of virility and sexual power for men. Metabolic profiling of the aqueous extract of E. longifolia (AEEL) using UPLC-MS/MS in both positive and negative modes allowed the identification of seventeen metabolites. The identified compounds were classified into four groups: quassinoids, alkaloids, triterpenes, and biphenylneolignans. AEEL is considered safe with oral LD50 cut-off >5000 mg/kg. Oral administration of 50, 100, 200, 400, or 800 mg/kg of AEEL for 10 consecutive days to Sprague-Dawley male rats caused significant reductions in mounting, intromission, and ejaculation latencies and increased penile erection index. AEEL increased total body weight and relative weights of seminal vesicles and prostate. Total and free serum testosterone and brain cortical and hippocampal dopamine content was significantly elevated in treated groups with no significant effects on serotonin or noradrenaline content.
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Bowyer JF, Hanig JP. Amphetamine- and methamphetamine-induced hyperthermia: Implications of the effects produced in brain vasculature and peripheral organs to forebrain neurotoxicity. Temperature (Austin) 2014; 1:172-82. [PMID: 27626044 PMCID: PMC5008711 DOI: 10.4161/23328940.2014.982049] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 10/22/2014] [Accepted: 10/27/2014] [Indexed: 12/20/2022] Open
Abstract
The adverse effects of amphetamine- (AMPH) and methamphetamine- (METH) induced hyperthermia on vasculature, peripheral organs and peripheral immune system are discussed. Hyperthermia alone does not produce amphetamine-like neurotoxicity but AMPH and METH exposures that do not produce hyperthermia (≥40°C) are minimally neurotoxic. Hyperthermia likely enhances AMPH and METH neurotoxicity directly through disruption of protein function, ion channels and enhanced ROS production. Forebrain neurotoxicity can also be indirectly influenced through the effects of AMPH- and METH- induced hyperthermia on vasculature. The hyperthermia and the hypertension produced by high doses amphetamines are a primary cause of transient breakdowns in the blood-brain barrier (BBB) resulting in concomitant regional neurodegeneration and neuroinflammation in laboratory animals. This BBB breakdown can occur in the amygdala, thalamus, striatum, sensory and motor cortex and hippocampus. Under these conditions, repetitive seizures greatly enhance neurodegeneration in hippocampus, thalamus and amygdala. Even when the BBB is less disrupted, AMPH- or METH- induced hyperthermia effects on brain vasculature may play a role in neurotoxicity. In this case, striatal and cortical vascular function are adversely affected, and even greater ROS, immune and damage responses are seen in the meninges and cortical surface vasculature. Finally, muscle and liver damage and elevated cytokines in blood can result when amphetamines produce hyperthermia. Proteins, from damaged muscle may activate the peripheral immune system and exacerbate liver damage. Liver damage can further increase cytokine levels, immune system activation and increase ammonia levels. These effects could potentially enhance vascular damage and neurotoxicity.
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Kelly KA, Miller DB, Bowyer JF, O’Callaghan JP. Chronic exposure to corticosterone enhances the neuroinflammatory and neurotoxic responses to methamphetamine. J Neurochem 2012; 122:995-1009. [PMID: 22776046 PMCID: PMC4706460 DOI: 10.1111/j.1471-4159.2012.07864.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Up-regulation of proinflammatory cytokines and chemokines in brain ("neuroinflammation") accompanies neurological disease and neurotoxicity. Previously, we documented a striatal neuroinflammatory response to acute administration of a neurotoxic dose of methamphetamine (METH), i.e. one associated with evidence of dopaminergic terminal damage and activation of microglia and astroglia. When we used minocycline to suppress METH-induced neuroinflammation, indices of dopaminergic neurotoxicity were not affected, but suppression of neuroinflammation was incomplete. Here, we administered the classic anti-inflammatory glucocorticoid, corticosterone (CORT), in an attempt to completely suppress METH-related neuroinflammation. METH alone caused large increases in striatal proinflammatory cytokine/chemokine mRNA and subsequent astrocytic hypertrophy, microglial activation, and dopaminergic nerve terminal damage. Pre-treatment of mice with acute CORT failed to prevent neuroinflammatory responses to METH. Surprisingly, when mice were pre-treated with chronic CORT in the drinking water, an enhanced striatal neuroinflammatory response to METH was observed, an effect that was accompanied by enhanced METH-induced astrogliosis and dopaminergic neurotoxicity. Chronic CORT pre-treatment also sensitized frontal cortex and hippocampus to mount a neuroinflammatory response to METH. Because the levels of chronic CORT used are associated with high physiological stress, our data suggest that chronic CORT therapy or sustained physiological stress may sensitize the neuroinflammatory and neurotoxicity responses to METH.
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Affiliation(s)
- Kimberly A. Kelly
- Health Effects Laboratory Division, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Diane B. Miller
- Health Effects Laboratory Division, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - John F. Bowyer
- Division of Neurotoxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR, USA
| | - James P. O’Callaghan
- Health Effects Laboratory Division, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, WV, USA
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Estimating false discovery rate and false non-discovery rate using the empirical cumulative distribution function of p-values in ‘omics’ studies. Genes Genomics 2011. [DOI: 10.1007/s13258-011-0052-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Thomas M, George NI, Saini UT, Patterson TA, Hanig JP, Bowyer JF. Endoplasmic reticulum stress responses differ in meninges and associated vasculature, striatum, and parietal cortex after a neurotoxic amphetamine exposure. Synapse 2011; 64:579-93. [PMID: 20340164 DOI: 10.1002/syn.20763] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Amphetamine (AMPH) is used to treat attention deficit and hyperactivity disorders, but it can produce neurotoxicity and adverse vascular effects at high doses. The endoplasmic reticulum (ER) stress response (ERSR) entails the unfolded protein response, which helps to avoid or minimize ER dysfunction. ERSR is often associated with toxicities resulting from the accumulation of unfolded or misfolded proteins and has been associated with methamphetamine toxicity in the striatum. The present study evaluates the effect of AMPH on several ERSR elements in meninges and associated vasculature (MAV), parietal cortex, and striatum. Adult, male Sprague-Dawley rats were exposed to saline, environmentally induced hyperthermia (EIH) or four consecutive doses of AMPH that produce hyperthermia. Expression changes (mRNA and protein levels) of key ERSR-related genes in MAV, striatum, and parietal cortex at 3 h or 1 day postdosing were monitored. AMPH increased the expression of some ERSR-related genes in all tissues. Atf4 (activating transcription factor 4, an indicator of Perk pathway activation), Hspa5/Grp78 (Glucose regulated protein 78, master regulator of ERSR), Pdia4 (protein disulfide isomerase, protein-folding enzyme), and Nfkb1 (nuclear factor of kappa b, ERSR sensor) mRNA increased significantly in MAV and parietal cortex 3 h after AMPH. In striatum, Atf4 and Hspa5/Grp78 mRNA significantly increased 3 h after AMPH, but Pdia4 and Nfkb11 did not. Thus, AMPH caused a robust activation of the Perk pathway in all tissues, but significant Ire1 pathway activation occurred only after AMPH treatment in the parietal cortex and striatum. Ddit3/Chop, a downstream effector of the ERSR pathway related to the neurotoxicity, was only increased in striatum and parietal cortex. Conversely, Pdia4, an enzyme protective in the ERSR, was only increased in MAV. The overall ERSR manifestation varied significantly between MAV, striatum, and parietal cortex after a neurotoxic exposure to AMPH.
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Affiliation(s)
- Monzy Thomas
- National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079-9502, USA
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Thomas M, George NI, Patterson TA, Bowyer JF. Amphetamine and environmentally induced hyperthermia differentially alter the expression of genes regulating vascular tone and angiogenesis in the meninges and associated vasculature. Synapse 2009; 63:881-94. [PMID: 19582783 DOI: 10.1002/syn.20661] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
An amphetamine (AMPH) regimen that does not produce a prominent blood-brain barrier breakdown was shown to significantly alter the expression of genes regulating vascular tone, immune function, and angiogenesis in vasculature associated with arachnoid and pia membranes of the forebrain. Adult-male Sprague-Dawley rats were given either saline injections during environmentally-induced hyperthermia (EIH) or four doses of AMPH with 2 h between each dose (5, 7.5, 10, and 10 mg/kg d-AMPH, s.c.) that produced hyperthermia. Rats were sacrificed either 3 h or 1 day after dosing, and total RNA and protein was isolated from the meninges, arachnoid and pia membranes, and associated vasculature (MAV) that surround the forebrain. Vip, eNos, Drd1a, and Edn1 (genes regulating vascular tone) were increased by either EIH or AMPH to varying degrees in MAV, indicating that EIH and AMPH produce differential responses to enhance vasodilatation. AMPH, and EIH to a lesser extent, elicited a significant inflammatory response at 3 h as indicated by an increased MAV expression of cytokines Il1b, Il6, Ccl-2, Cxcl1, and Cxcl2. Also, genes related to heat shock/stress and disruption of vascular homeostasis such as Icam1 and Hsp72 were also observed. The increased expression of Ctgf and Timp1 and the decreased expression of Akt1, Anpep, and Mmp2 and Tek (genes involved in stimulating angiogenesis) from AMPH exposure suggest that angiogenesis was arrested or disrupted in MAV to a greater extent by AMPH compared to EIH. Alterations in vascular-related gene expression in the parietal cortex and striatum after AMPH were less in magnitude than in MAV, indicating less of a disruption of vascular homeostasis in these two regions. Changes in the levels of insulin-like growth factor binding proteins Igfbp1, 2, and 5 in MAV, compared to those in striatum and parietal cortex, imply an interaction between these regions to regulate the levels of insulin-like growth factor after AMPH damage. Thus, the vasculature and meninges surrounding the surface of the forebrain may be an important region in which AMPHs can disrupt vascular homeostasis.
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Affiliation(s)
- Monzy Thomas
- US Food and Drug Administration, National Center for Toxicological Research, Division of Neurotoxicology, 3900 NCTR Road, Jefferson, Arkansas 72079, USA
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Lin TC, Huang LT, Huang YN, Chen GS, Wang JY. Neonatal status epilepticus alters prefrontal-striatal circuitry and enhances methamphetamine-induced behavioral sensitization in adolescence. Epilepsy Behav 2009; 14:316-23. [PMID: 19126440 DOI: 10.1016/j.yebeh.2008.12.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2008] [Revised: 11/30/2008] [Accepted: 12/13/2008] [Indexed: 11/24/2022]
Abstract
Neonatal seizures may alter the developing neurocircuitry and cause behavioral abnormalities in adulthood. We found that rats previously subjected to lithium-pilocarpine (LiPC)-induced neonatal status epilepticus (NeoSE) exhibited enhanced behavioral sensitization to methamphetamine (MA) in adolescence. Neurochemically, dopamine (DA) and metabolites were markedly decreased in prefrontal cortex (PFC) and insignificantly changed in striatum by NeoSE, but were increased in both PFC and striatum by NeoSE+MA. Glutamate levels were increased in both PFC and striatum in the NeoSE+MA group. DA turnover, an index of utilization and activity, was increased by NeoSE but reversed by MA in PFC. Gene expression of the regulator of G-protein signaling 4 (RGS4) was downregulated in PFC and striatum by NeoSE and further suppressed by MA. These findings suggest NeoSE affects both dopaminergic and glutamatergic systems in the prefrontal-striatal circuitry that manifests as enhanced behavioral sensitization to MA in adolescence.
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Affiliation(s)
- Tzu-Chao Lin
- Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan, ROC
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Zhou T, Chou J, Watkins PB, Kaufmann WK. Toxicogenomics: transcription profiling for toxicology assessment. EXS 2009; 99:325-66. [PMID: 19157067 DOI: 10.1007/978-3-7643-8336-7_12] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Toxicogenomics, the application of transcription profiling to toxicology, has been widely used for elucidating the molecular and cellular actions of chemicals and other environmental stressors on biological systems, predicting toxicity before any functional damages, and classification of known or new toxicants based on signatures of gene expression. The success of a toxicogenomics study depends upon close collaboration among experts in different fields, including a toxicologist or biologist, a bioinformatician, statistician, physician and, sometimes, mathematician. This review is focused on toxicogenomics studies, including transcription profiling technology, experimental design, significant gene extraction, toxicological results interpretation, potential pathway identification, database input and the applications of toxicogenomics in various fields of toxicological study.
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Affiliation(s)
- Tong Zhou
- Center for Drug Safety Sciences, The Hamner Institutes for Health Sciences, University of North Carolina at Chapel Hill, Research Triangle Park, NC, USA.
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Bowyer J, Latendresse J, Delongchamp R, Muskhelishvili L, Warbritton A, Thomas M, Tareke E, McDaniel L, Doerge D. The effects of subchronic acrylamide exposure on gene expression, neurochemistry, hormones, and histopathology in the hypothalamus–pituitary–thyroid axis of male Fischer 344 rats. Toxicol Appl Pharmacol 2008; 230:208-15. [DOI: 10.1016/j.taap.2008.02.028] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2008] [Revised: 01/30/2008] [Accepted: 02/22/2008] [Indexed: 11/25/2022]
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Bowyer JF, Robinson B, Ali S, Schmued LC. Neurotoxic-related changes in tyrosine hydroxylase, microglia, myelin, and the blood-brain barrier in the caudate-putamen from acute methamphetamine exposure. Synapse 2008; 62:193-204. [PMID: 18081184 DOI: 10.1002/syn.20478] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Changes in the histological morphology of the caudate-putamen (CPu) were determined after a high-dose methamphetamine (METH) exposure in an effort to elucidate whether BBB disruption plays a role in CPu neurotoxicity. This was accomplished by evaluating the tyrosine hydroxylase immunoreactivity (TH-IR), isolectin B4 reactivity, Black Gold II (BG-II) and Fluoro-Jade C (FJ-C) staining, and immunoreactivity to mouse immunoglobulin G (IgG-IR) in adult male mice at 90-min, 4-h, 12-h, 1-day, and 3-day post-METH exposure. The IgG-IR indicated that the BBB was only modestly altered in the CPu at time points after neurodegeneration occurred and dependent on hyperthermia and status epilepticus. The modest CPu IgG-IR changes observed in the perivascular areas indicated that immunoglobulins were present on some CPu microglia 1 day or more after METH. The first signs of CPu damage were swellings in the TH-IR axons, myelin damage, and a few degenerating neurons at 4-h post-METH. The loss of TH-IR was dependent on hyperthermia but not seizures or CPu neurodegeneration, and the TH-IR was virtually absent throughout the CPu within 12 h. Surprisingly, signs of FJ-C labeling (degenerating) axons in the CPu were seen only in the regions of pronounced somatic neurodegeneration and independent of TH-IR loss. Microglial activation did not occur until 1 day or more post-METH. In summary, a major BBB disruption within the CPu does not directly contribute to neurotoxicity in this single high-dose METH exposure. However, seizure activity produced or exacerbated by amygdalar BBB disruption can significantly increase CPu somatic neurodegeneration (but not affect dopamine (DA) terminal damage). The time course of microglial activation indicates a response to the neurodegeneration, myelin damage, and/or damaged DA terminals after loss of TH-IR.
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Affiliation(s)
- John F Bowyer
- Division of Neurotoxicology, National Center for Toxicological Research, Jefferson, AR 72079, USA.
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Tareke E, Bowyer JF, Doerge DR. Quantification of rat brain neurotransmitters and metabolites using liquid chromatography/electrospray tandem mass spectrometry and comparison with liquid chromatography/electrochemical detection. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2007; 21:3898-3904. [PMID: 17979107 DOI: 10.1002/rcm.3295] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Analytical methodology based on solid-phase extraction, polar reversed-phase liquid chromatography, and electrospray tandem mass spectrometry (LC/MS/MS) with isotope dilution was developed and validated for quantifying the neurotransmitters, dopamine and serotonin, and their major metabolites in brain tissue. Limits of detection (0.1-20 pg/mg tissue) were sufficient for analysis of multiple neurotransmitters in rat brain regions, including parietal cortex, hypothalamus, pituitary, substantia nigra, and striatum. Method performance was compared with contemporaneous measurements using a well-established procedure based on ion-pairing reversed-phase liquid chromatography and amperometric detection. The principal advantages of the LC/MS/MS method include a more robust sample purification procedure, an optimized chromatographic separation, and the qualitative and quantitative assurance that comes from coeluting isotopically labeled internal standards; however, sensitivity did not consistently improve upon that provided by amperometric detection. This methodology may be particularly useful for applications in which simultaneous determinations are required for drugs and their affected neurotransmitters in specific brain regions.
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Affiliation(s)
- Eden Tareke
- National Center for Toxicological Research, US Food and Drug Administration, Jefferson, AR 72079, USA
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Straiko MMW, Coolen LM, Zemlan FP, Gudelsky GA. The effect of amphetamine analogs on cleaved microtubule-associated protein-tau formation in the rat brain. Neuroscience 2006; 144:223-31. [PMID: 17084036 PMCID: PMC1817812 DOI: 10.1016/j.neuroscience.2006.08.073] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2006] [Revised: 08/26/2006] [Accepted: 08/29/2006] [Indexed: 11/16/2022]
Abstract
The present study quantified the cleaved form of the microtubule-associated protein tau (cleaved MAP-tau, C-tau), a previously demonstrated marker of CNS toxicity, following the administration of monoamine-depleting regimens of the psychostimulant drugs amphetamine (AMPH), methamphetamine (METH), +/-3,4-methylenedioxymethamphetamine (MDMA), or para-methoxyamphetamine (PMA) in an attempt to further characterize psychostimulant-induced toxicity. A dopamine (DA)-depleting regimen of AMPH produced an increase in C-tau immunoreactivity in the striatum, while a DA- and serotonin (5-HT)-depleting regimen of METH produced an increase in the number of C-tau immunoreactive cells in the striatum and CA2/CA3 and dentate gyrus regions of the hippocampus. MDMA and PMA, two psychostimulant drugs that produce selective 5-HT depletion in the striatum, had no effect on C-tau immunoreactivity in the striatum or hippocampus. Furthermore, 5,7-dihydroxytryptamine (5,7-DHT), an established 5-HT selective neurotoxin, did not produce an increase in C-tau immunoreactivity. Dual fluorescent immunocytochemistry with antibodies to glial fibrillary acidic protein (GFAP) and C-tau indicated that C-tau immunoreactivity was present in astrocytes, not neurons, suggesting that increased C-tau may be an alternative indicator of reactive gliosis. The present results are consistent with previous findings that the DA-depleting psychostimulants AMPH and METH produce reactive gliosis whereas the 5-HT-depleting drugs MDMA and PMA, as well as the known 5-HT selective neurotoxin 5,7-DHT, do not produce an appreciable glial response.
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Affiliation(s)
- M M W Straiko
- Neuroscience Graduate Program, University of Cincinnati, Cincinnati, OH 45267, USA
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Shilling PD, Kuczenski R, Segal DS, Barrett TB, Kelsoe JR. Differential regulation of immediate-early gene expression in the prefrontal cortex of rats with a high vs low behavioral response to methamphetamine. Neuropsychopharmacology 2006; 31:2359-67. [PMID: 16855532 DOI: 10.1038/sj.npp.1301162] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Methamphetamine (METH) administration mimics many of the symptoms of mania and can produce psychosis after chronic use. Both rodents and man display interindividual variation in response to METH. The molecular mechanisms underlying these differences might be relevant to both stimulant addiction and endogenous psychosis. We treated 50 Sprague-Dawley rats acutely with METH (4.0 mg/kg) and 10 control rats with saline, and measured their behavior for 3 h after drug administration. Animals were divided into high responders (HR) (top 20%) and low responders (LR) (lowest 20%) based on their stereotypy response. They were killed 24 h after injection. Total RNA was extracted from the prefrontal cortex (PFC) and the expression of approximately 30 000 transcripts were analyzed using Affymetrix 230 2.0 GeneChips. Real-time reverse transcription-polymerase chain reaction was used to validate the expression of a select group of genes. Forty-three genes exhibited significant differences in expression in HR vs LR 24 h after METH treatment including a group of immediate-early genes (IEGs) (eg, c-fos, junB, NGFI-B, serum-regulated glucocorticoid kinase). These IEG expression differences were accompanied by the significant downregulation of many of these genes compared to saline in the HR but not LR, suggesting a differential responsiveness of signal transduction pathways in these two groups of rats. In addition, the expression of other transcription factors in the PFC was significantly different in HR compared to LR. These gene expression changes may contribute to individual differences in responsiveness to stimulants and the development of mania and psychosis.
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Affiliation(s)
- Paul D Shilling
- Department of Psychiatry, University of California, San Diego, CA 92093, USA
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Bowyer JF, Pogge AR, Delongchamp RR, O'Callaghan JP, Patel KM, Vrana KE, Freeman WM. A threshold neurotoxic amphetamine exposure inhibits parietal cortex expression of synaptic plasticity-related genes. Neuroscience 2006; 144:66-76. [PMID: 17049170 PMCID: PMC2039899 DOI: 10.1016/j.neuroscience.2006.08.076] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2006] [Revised: 08/23/2006] [Accepted: 08/29/2006] [Indexed: 11/25/2022]
Abstract
Compulsive drug abuse has been conceptualized as a behavioral state where behavioral stimuli override normal decision making. Clinical studies of methamphetamine users have detailed decision making changes and imaging studies have found altered metabolism and activation in the parietal cortex. To examine the molecular effects of amphetamine (AMPH) on the parietal cortex, gene expression responses to amphetamine challenge (7.5 mg/kg) were examined in the parietal cortex of rats pretreated for nine days with either saline, non-neurotoxic amphetamine, or neurotoxic AMPH dosing regimens. The neurotoxic AMPH exposure [three doses of 7.5 mg/kg/day AMPH (6 h between doses), for nine days] produced histological signs of neurotoxicity in the parietal cortex while a non-neurotoxic dosing regimen (2.0 mg/kg/day x 3) did not. Neurotoxic AMPH pretreatment resulted in significantly diminished AMPH challenge-induced mRNA increases of activity-regulated cytoskeletal protein (ARC), nerve growth-factor inducible protein A (NGFI-A), and nerve growth-factor inducible protein B (NGFI-B) in the parietal cortex while neither saline pretreatment nor non-neurotoxic AMPH pretreatment did. This effect was specific to these genes as tissue plasminogen activator (t-PA), neuropeptide Y (NPY) and c-jun expression in response to AMPH challenge was unaltered or enhanced by amphetamine pretreatments. In the striatum, there were no differences between saline, neurotoxic AMPH, and non-neurotoxic AMPH pretreatments on ARC, NGFI-A or NGFI-B expression elicited by the AMPH challenge. These data indicate that the responsiveness of synaptic plasticity-related genes is sensitive to disruption specifically in the parietal cortex by threshold neurotoxic AMPH exposures.
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Affiliation(s)
- J F Bowyer
- Division of Neurotoxicology, National Center for Toxicological Research, HFT-132, Jefferson, AR 72079, USA.
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Easton N, Marsden CA. Ecstasy: are animal data consistent between species and can they translate to humans? J Psychopharmacol 2006; 20:194-210. [PMID: 16510478 DOI: 10.1177/0269881106061153] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The number of 3,4-methylenedioxymethamphetamine (ecstasy or MDMA) animal research articles is rapidly increasing and yet studies which place emphasis on the clinical significance are limited due to a lack of reliable human data. MDMA produces an acute, rapid release of brain serotonin and dopamine in experimental animals and in the rat this is associated with increased locomotor activity and the serotonin behavioural syndrome in rats. MDMA causes dose-dependent hyperthermia, which is potentially fatal, in humans, primates and rodents. Subsequent serotonergic neurotoxicity has been demonstrated by biochemical and histological studies and is reported to last for months in rats and years in non-human primates. Relating human data to findings in animals is complicated by reports that MDMA exposure in mice produces selective long-term dopaminergic impairment with no effect on serotonin. This review compares data obtained from animal and human studies and examines the acute physiological, behavioural and biochemical effects of MDMA as well as the long-term behavioural effects together with serotonergic and dopaminergic impairments. Consideration is also given to the role of neurotoxic metabolites and the influence of age, sex and user groups on the long-term actions of MDMA.
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Affiliation(s)
- Neil Easton
- School of Biomedical Science, University of Nottingham, Queen's Medical Centre, UK.
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Zhu JP, Xu W, Angulo N, Angulo JA. Methamphetamine-induced striatal apoptosis in the mouse brain: comparison of a binge to an acute bolus drug administration. Neurotoxicology 2005; 27:131-6. [PMID: 16165214 PMCID: PMC2896282 DOI: 10.1016/j.neuro.2005.05.014] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2004] [Revised: 05/27/2005] [Accepted: 05/30/2005] [Indexed: 11/18/2022]
Abstract
Methamphetamine (METH) is a psychostimulant that induces neural damage in experimental animals and humans. A binge (usually in the 5-10 mg/kg dose range 4 x at 2 h intervals) and the acute bolus drug administration (20-40 mg/kg) of METH have been employed frequently to study neurotoxicity in the brain. In this study we have compared these drug delivery schedules to determine their efficacy to induce striatal apoptosis. Exposure of male mice to a binge of METH at 10mg/kg 4x at 2 h intervals (cumulative dose of 40 mg/kg) was approximately four times less effective in inducing apoptotic cell death (TUNEL staining) 24 h after METH treatment in the striatum than a single bolus administration of 30 mg/kg of METH. The residual TUNEL staining observed three days after METH treatment is proportionately equivalent between a binge and the acute bolus drug administration. Interestingly, a binge of METH induces a hyperthermic response of longer duration. This study demonstrates that an acute bolus drug administration of METH is more effective inducing striatal apoptosis in mice, and therefore, is more suitable for studies assessing the impact of METH on sites post-synaptic to the striatonigral dopamine terminals.
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Affiliation(s)
| | | | | | - Jesus A. Angulo
- Corresponding author: Tel.: +1 212 772 5232; fax: +1 212 772 5230. (J.A. Angulo)
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Slikker W, Bowyer JF. Biomarkers of adult and developmental neurotoxicity. Toxicol Appl Pharmacol 2005; 206:255-60. [PMID: 15967216 DOI: 10.1016/j.taap.2004.09.022] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2004] [Accepted: 09/08/2004] [Indexed: 11/16/2022]
Abstract
Neurotoxicity may be defined as any adverse effect on the structure or function of the central and/or peripheral nervous system by a biological, chemical, or physical agent. A multidisciplinary approach is necessary to assess adult and developmental neurotoxicity due to the complex and diverse functions of the nervous system. The overall strategy for understanding developmental neurotoxicity is based on two assumptions: (1) significant differences in the adult versus the developing nervous system susceptibility to neurotoxicity exist and they are often developmental stage dependent; (2) a multidisciplinary approach using neurobiological, including gene expression assays, neurophysiological, neuropathological, and behavioral function is necessary for a precise assessment of neurotoxicity. Application of genomic approaches to developmental studies must use the same criteria for evaluating microarray studies as those in adults including consideration of reproducibility, statistical analysis, homogenous cell populations, and confirmation with non-array methods. A study using amphetamine to induce neurotoxicity supports the following: (1) gene expression data can help define neurotoxic mechanism(s), (2) gene expression changes can be useful biomarkers of effect, and (3) the site-selective nature of gene expression in the nervous system may mandate assessment of selective cell populations.
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Affiliation(s)
- William Slikker
- Division of Neurotoxicology, National Center for Toxicological Research/FDA, HFT-132, 3900 NCTR Road, Jefferson, AR 72079-9502, USA.
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Fang H, Tong W, Shi L, Jakab RL, Bowyer JF. Classification of cDNA array genes that have a highly significant discriminative power due to their unique distribution in four brain regions. DNA Cell Biol 2005; 23:661-74. [PMID: 15585124 DOI: 10.1089/dna.2004.23.661] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Novel statistical methods were used to distinguish functionally distinct brain regions using their cDNA array gene expression profiles, and it was found that one of four specific factors is often associated with the most regionally discriminative genes. The gene expression profiles for the substantia nigra (SN), striatum (STR), parietal cortex (PC), and posterolateral cortical amygdaloid nucleus (PLCo) brain regions were determined from each brain region. An F-test identified 339 genes of the 1185 array genes as having a P < or = 0.01 and applied a gene ranking and selection method based on Soft Independent Modeling of Class Analogy (SIMCA) to obtain 59 of the most discriminative genes. Their discriminative power was validated in three steps. The most convincing step showed their ability to correctly predict the brain regional classifications for 18 "test" gene expression sets obtained from the four regions. A two-way Hierarchical Cluster Analysis organized the 59 genes in six clusters according to their expression differences in the brain regions. Expression patterns in the SN and STR regions greatly differed from each other and the PC and PLCo. The closer similarity in the gene expression patterns of the PC and PLCo was probably due to their functional similarity. The important factors in determining differences in the regional gene expression profiles in six clusters were (1) regional myelin/oligodendrocyte levels, (2) resident neuron types, (3) neurotransmitter innervation profiles, and (4) Ca++-dependent signaling and second messenger systems.
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Affiliation(s)
- Hong Fang
- Northrop Grumman Information Technology, Jefferson, Arkansas, USA
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Delongchamp RR, Bowyer JF, Chen JJ, Kodell RL. Multiple-testing strategy for analyzing cDNA array data on gene expression. Biometrics 2005; 60:774-82. [PMID: 15339301 DOI: 10.1111/j.0006-341x.2004.00228.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
An objective of many functional genomics studies is to estimate treatment-induced changes in gene expression. cDNA arrays interrogate each tissue sample for the levels of mRNA for hundreds to tens of thousands of genes, and the use of this technology leads to a multitude of treatment contrasts. By-gene hypotheses tests evaluate the evidence supporting no effect, but selecting a significance level requires dealing with the multitude of comparisons. The p-values from these tests order the genes such that a p-value cutoff divides the genes into two sets. Ideally one set would contain the affected genes and the other would contain the unaffected genes. However, the set of genes selected as affected will have false positives, i.e., genes that are not affected by treatment. Likewise, the other set of genes, selected as unaffected, will contain false negatives, i.e., genes that are affected. A plot of the observed p-values (1 - p) versus their expectation under a uniform [0, 1] distribution allows one to estimate the number of true null hypotheses. With this estimate, the false positive rates and false negative rates associated with any p-value cutoff can be estimated. When computed for a range of cutoffs, these rates summarize the ability of the study to resolve effects. In our work, we are more interested in selecting most of the affected genes rather than protecting against a few false positives. An optimum cutoff, i.e., the best set given the data, depends upon the relative cost of falsely classifying a gene as affected versus the cost of falsely classifying a gene as unaffected. We select the cutoff by a decision-theoretic method analogous to methods developed for receiver operating characteristic curves. In addition, we estimate the false discovery rate and the false nondiscovery rate associated with any cutoff value. Two functional genomics studies that were designed to assess a treatment effect are used to illustrate how the methods allowed the investigators to determine a cutoff to suit their research goals.
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Affiliation(s)
- Robert R Delongchamp
- Division of Biometry and Risk Assessment, National Center for Toxicological Research, Jefferson, Arkansas 72079, USA.
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Bowyer JF, Delongchamp RR, Jakab RL. Glutamate N-methyl-d-aspartate and dopamine receptors have contrasting effects on the limbic versus the somatosensory cortex with respect to amphetamine-induced neurodegeneration. Brain Res 2004; 1030:234-46. [PMID: 15571672 DOI: 10.1016/j.brainres.2004.10.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/19/2004] [Indexed: 01/02/2023]
Abstract
The roles that glutamate N-methyl-D-aspartate (NMDA) and dopamine D1-like and D2-like receptors play in the cortical neurotoxicity occurring in rats exposed to multiple doses of amphetamine (AMPH) for 2 days was evaluated. Neurodegeneration in rats that did not become hyperthermic during AMPH exposure was quantified by counting isolectin B4-labeled phagocytic microglia and Fluoro-Jade (F-J)-labeled neurons in the somatosensory parietal cortex, piriform cortex and posterolateral cortical amygdaloid nucleus (PLCo). The NMDA receptor antagonist, dizocilpine (0.63 mg/kg day) blocked AMPH-induced neurodegeneration in the somatosensory cortex. However, it did not affect degeneration in the piriform cortex and PLCo indicating that limbic degeneration was not NMDA-mediated. The dopamine antagonists, eticlopride (D2/3, 0.25 mg/kg day) and SCH-23390 (D1, 0.25 mg/kg day), blocked the stereotypic behavior and neurodegeneration in the somatosensory cortex. However, eticlopride had a lesser protective effect in the limbic regions. As well, the dopamine D2/D3 agonist quinpirole (1.5 mg/kg day) protected against cortical neurodegeneration when it was given during AMPH exposure and continued until sacrifice. The dopamine D1 agonist (SKF-38393, 12.5 mg/kg day) had no significant effect on neurodegeneration. These data indicate that there are significant differences in NMDA and dopamine D2 modulation of AMPH-induced neurodegeneration in the somatosensory cortex compared to the limbic cortices, and limbic cortical degeneration is not necessarily dependent on excessive stimulation of NMDA receptors as it is in the somatosensory cortex. Although excessive dopamine receptor stimulation during amphetamine exposure may trigger the neurodegenerative processes, continued D2 stimulation after AMPH exposure is neuroprotective in the cortex.
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Affiliation(s)
- John F Bowyer
- Division of Neurotoxicology, National Center for Toxicological Research, Jefferson, Arkansas 72079, USA.
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