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Smith GS, Mills KA, Pontone GM, Anderson WS, Perepezko KM, Brasic J, Zhou Y, Brandt J, Butson CR, Holt DP, Mathews WB, Dannals RF, Wong DF, Mari Z. Effect of STN DBS on vesicular monoamine transporter 2 and glucose metabolism in Parkinson's disease. Parkinsonism Relat Disord 2019; 64:235-241. [PMID: 31053531 DOI: 10.1016/j.parkreldis.2019.04.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 04/04/2019] [Accepted: 04/07/2019] [Indexed: 01/21/2023]
Abstract
INTRODUCTION Deep brain stimulation (DBS) is an established treatment for Parkinson's Disease (PD). Despite the improvement of motor symptoms in most patients by sub-thalamic nucleus (STN) DBS and its widespread use, the neurobiological mechanisms are not completely understood. The objective of the present study was to elucidate the effects of subthalamic nucleus (STN) DBS in PD on the dopamine system and neural circuitry, employing high-resolution positron emission tomography (PET) imaging. The hypotheses tested were that STN DBS would decrease the striatal vesicular monoamine transporter (VMAT2), secondary to an increase in dopamine concentrations, and would decrease striatal cerebral metabolism and increase cortical cerebral metabolism. METHODS PET imaging of the vesicular monoamine transporter (VMAT2) and cerebral glucose metabolism was performed prior to DBS surgery and after 4-6 months of STN stimulation in seven PD patients (mean age 67 ± 7). RESULTS The patients demonstrated significant improvement in motor and neuropsychiatric symptoms after STN DBS. Decreased VMAT2 was observed in the caudate, putamen and associative striatum and in extra-striatal, cortical and limbic regions. Cerebral glucose metabolism was decreased in striatal sub-regions and increased in temporal and parietal cortices and the cerebellum. Decreased striatal VMAT2 was correlated with decreased striatal and increased cortical and limbic metabolism. Improvement of depressive symptoms was correlated with decreased VMAT2 in striatal and extra-striatal regions and with striatal decreases and cortical increases in metabolism. CONCLUSIONS The present results support further investigation of the role of VMAT2, and associated changes in neural circuitry in the improvement of motor and non-motor symptoms with STN DBS in PD.
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Affiliation(s)
- Gwenn S Smith
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Division of Nuclear Medicine and Molecular Imaging, Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Kelly A Mills
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Greg M Pontone
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - W Stanley Anderson
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Kate M Perepezko
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - James Brasic
- Section of High Resolution Brain PET, Division of Nuclear Medicine, Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yun Zhou
- Section of High Resolution Brain PET, Division of Nuclear Medicine, Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jason Brandt
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Christopher R Butson
- Scientific Computing & Imaging (SCI) Institute, Departments of Biomedical Engineering, Neurology, Neurosurgery & Psychiatry, University of Utah, USA
| | - Daniel P Holt
- Division of Nuclear Medicine and Molecular Imaging, Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - William B Mathews
- Division of Nuclear Medicine and Molecular Imaging, Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Robert F Dannals
- Division of Nuclear Medicine and Molecular Imaging, Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Dean F Wong
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Section of High Resolution Brain PET, Division of Nuclear Medicine, Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Zoltan Mari
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, NV, USA
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Asser A, Kõks S, Snellman A, Haaparanta-Solin M, Arponen E, Grönroos T, Nairismägi J, Bergquist J, Soomets U, Piip P, Eltermaa M, Sauk M, Lindmäe H, Rinne JO, Taba P. Increased striatal VMAT2 binding in mice after chronic administration of methcathinone and manganese. Brain Res 2016; 1652:97-102. [PMID: 27693414 DOI: 10.1016/j.brainres.2016.09.034] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 09/24/2016] [Accepted: 09/26/2016] [Indexed: 11/30/2022]
Abstract
Intravenous use of a psychostimulant drug containing methcathinone (ephedrone) and manganese causes an irreversible extrapyramidal syndrome in drug abusers. We aimed to reproduce the syndrome in mice to evaluate dopaminergic damage. C57/B6 mice were intraperitoneally injected once a day with the study drug or saline for a period of 27 weeks. Motor activity was recorded in an automated motility-box. After 13 and 27 weeks of treatment, ex vivo digital autoradiography was performed using [11C]dihydrotetrabenazine ([11C]DTBZ). After 27 weeks of treatment [11C]DTBZ autoradiography demonstrated a significant increase in the striatum-to-cerebellum binding ratio compared with saline treated controls. At the same time point, there was no evident change in motor activity. Increased [11C]DTBZ binding may indicate vesicular monoamine transporter type 2 (VMAT2) function is altered. The lack of extrapyramidal symptoms in animals could be attributed to low dosing regimen or high metabolic rate.
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Affiliation(s)
- Andres Asser
- Department of Neurology and Neurosurgery, University of Tartu, Tartu, Estonia
| | - Sulev Kõks
- Department of Pathophysiology, University of Tartu, Tartu, Estonia
| | | | | | | | - Tove Grönroos
- Turku PET Centre, University of Turku, Turku, Finland
| | - Jaak Nairismägi
- Institute of Gene Technology, Tallinn Technical University, Tallinn, Estonia
| | - Jonas Bergquist
- Department of Chemistry, Uppsala University, Uppsala, Sweden
| | - Ursel Soomets
- Department of Biochemistry, University of Tartu, Tartu, Estonia
| | - Piret Piip
- Department of Neurology and Neurosurgery, University of Tartu, Tartu, Estonia
| | - Mall Eltermaa
- Department of Neurology and Neurosurgery, University of Tartu, Tartu, Estonia
| | - Martin Sauk
- Department of Neurology and Neurosurgery, University of Tartu, Tartu, Estonia
| | - Hanna Lindmäe
- Department of Neurology and Neurosurgery, University of Tartu, Tartu, Estonia
| | - Juha O Rinne
- Turku PET Centre, University of Turku, Turku, Finland; Department of Neurology, Turku University Hospital, Turku, Finland
| | - Pille Taba
- Department of Neurology and Neurosurgery, University of Tartu, Tartu, Estonia.
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Huang ZR, Tsai CL, Huang YY, Shiue CY, Tzen KY, Yen RF, Hsin LW. A Novel Potential Positron Emission Tomography Imaging Agent for Vesicular Monoamine Transporter Type 2. PLoS One 2016; 11:e0161295. [PMID: 27612194 PMCID: PMC5017712 DOI: 10.1371/journal.pone.0161295] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Accepted: 07/06/2016] [Indexed: 12/02/2022] Open
Abstract
In the early 1990s, 9-(+)-11C-dihydrotetrabenazine (9-(+)-11C-DTBZ) was shown to be a useful positron emission tomography (PET) imaging agent for various neurodegenerative disorders. Here, we described the radiosynthesis and evaluation of the 9-(+)-11C-DTBZ analog, 10-(+)-11C-DTBZ, as a vesicular monoamine transporter 2 (VMAT2) imaging agent and compare it with 9-(+)-11C-DTBZ. 10-(+)-11C-DTBZ was obtained by 11C-MeI methylation with its 10 hydroxy precursor in the presence of 5 M NaOH. It had a slightly better average radiochemical yield of 35.3 ± 3.6% (decay-corrected to end of synthesis (EOS)) than did 9-(+)-11C-DTBZ (30.5 ± 2.3%). MicroPET studies showed that 10-(+)-11C-DTBZ had a striatum-to-cerebellum ratio of 3.74 ± 0.21 at 40 min post-injection, while the ratio of 9-(+)-11C-DTBZ was 2.50 ± 0.33. This indicated that 10-(+)-11C-DTBZ has a higher specific uptake in VMAT2-rich brain regions, and 10-(+)-11C-DTBZ may be a potential VMAT2 radioligand. Our experiment is the first study of 10-(+)-11C-DTBZ to include dynamic brain distribution in rat brains.
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Affiliation(s)
- Zih-Rou Huang
- School of Pharmacy, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chia-Ling Tsai
- PET Center, Department of Nuclear Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Ya-Yao Huang
- PET Center, Department of Nuclear Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Chyng-Yann Shiue
- PET Center, Department of Nuclear Medicine, National Taiwan University Hospital, Taipei, Taiwan
- Molecular Imaging Center, National Taiwan University, Taipei, Taiwan
- PET Center, Department of Nuclear Medicine, Tri-Service General Hospital, Taipei, Taiwan
| | - Kai-Yuan Tzen
- PET Center, Department of Nuclear Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Ruoh-Fang Yen
- PET Center, Department of Nuclear Medicine, National Taiwan University Hospital, Taipei, Taiwan
- Molecular Imaging Center, National Taiwan University, Taipei, Taiwan
| | - Ling-Wei Hsin
- School of Pharmacy, College of Medicine, National Taiwan University, Taipei, Taiwan
- Molecular Imaging Center, National Taiwan University, Taipei, Taiwan
- Center for Innovative Therapeutics Discovery, National Taiwan University, Taipei, Taiwan
- * E-mail:
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Rapid Recovery of Vesicular Dopamine Levels in Methamphetamine Users in Early Abstinence. Neuropsychopharmacology 2016; 41:1179-87. [PMID: 26321315 PMCID: PMC4748442 DOI: 10.1038/npp.2015.267] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 07/30/2015] [Accepted: 08/21/2015] [Indexed: 11/08/2022]
Abstract
We previously reported very low levels of dopamine in post-mortem striatum of chronic methamphetamine users, raising the possibility that restoration of normal dopamine levels could help in this addiction and perhaps prevent early relapse. To establish relevance of this finding to the living brain, we tested whether striatal [(11)C]-(+)-dihydrotetrabenazine binding, a vesicular monoamine transporter probe sensitive to changes in (stored) vesicular dopamine, is elevated in methamphetamine users. Chronic methamphetamine users underwent [(11)C]-(+)-dihydrotetrabenazine positron emission tomography scans during early (mean 2.6 days) and later (~10 days) abstinence. Striatal [(11)C]-(+)-dihydrotetrabenazine binding was elevated (suggesting low stored dopamine) in methamphetamine users (n=28; 2.6 days after last use) relative to controls (n=22) (+28%, p<0.0001) and correlated with severity and recency of drug use and with cognitive impairment and withdrawal symptoms. Mean [(11)C]-(+)-dihydrotetrabenazine binding levels in the subgroup of methamphetamine users who could remain abstinent ~10 days following last use (n=17) were normal at the follow-up scan. Our imaging data support post-mortem findings and suggest that chronic methamphetamine users have low brain levels of stored dopamine during very early abstinence from MA, which could contribute to behavioral and cognitive deficits. Findings also suggest a rapid recovery of stored dopamine in some methamphetamine users who become abstinent and who therefore might not benefit from dopamine replacement medication (eg, levodopa). Further study is necessary to establish whether those users who could not maintain abstinence for the second scan might have a more severe and persistent dopamine deficiency and who could benefit from this medication.
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Chen Z, Tang J, Liu C, Li X, Huang H, Xu X, Yu H. Effects of anesthetics on vesicular monoamine transporter type 2 binding to ¹⁸F-FP-(+)-DTBZ: a biodistribution study in rat brain. Nucl Med Biol 2015; 43:124-129. [PMID: 26526872 DOI: 10.1016/j.nucmedbio.2015.09.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 09/14/2015] [Accepted: 09/28/2015] [Indexed: 11/30/2022]
Abstract
OBJECTIVES The in vivo binding analysis of vesicular monoamine transporter type 2 (VMAT2) to radioligand has provided a means of investigating related disorders. Anesthesia is often inevitable when the investigations are performed in animals. In the present study, we tested effects of four commonly-used anesthetics: isoflurane, pentobarbital, chloral hydrate and ketamine, on in vivo VMAT2 binding to (18)F-FP-(+)-DTBZ, a specific VMAT2 radioligand, in rat brain. METHODS The transient equilibrium time window for in vivo binding of (18)F-FP-(+)-DTBZ after a bolus injection was firstly determined. The brain biodistribution studies under anesthetized and awake rats were then performed at the equilibrium time. Standard uptake values (SUVs) of the interest brain regions: the striatum (ST), hippocampus (HP), cortex (CX) and cerebellum (CB) were obtained; and ratios of tissue to cerebellum were calculated. RESULTS Isoflurane and pentobarbital did not alter distribution of (18)F-FP-(+)-DTBZ in the brain relative to the awake group; neither SUVs nor ratios of ST/CB and HP/CB were altered significantly. Chloral hydrate significantly increased SUVs of all the brain regions, but did not significantly alter ratios of ST/CB and HP/CB. Ketamine significantly increased SUVs of the striatum, hippocampus and cortex, and insignificantly increased the SUV of the cerebellum; consequently, ketamine significantly increased ratios of ST/CB and HP/CB. CONCLUSIONS It is concluded that in vivo VMAT2 binding to (18)F-FP-(+)-DTBZ are not altered by isoflurane and pentobarbital, but altered by chloral hydrate and ketamine. Isoflurane and pentobarbital may be promising anesthetic compounds for investigating in vivo VMAT2 binding. Further studies are warranted to investigate the interactions of anesthetics with VMAT2 binding potential with in vivo PET studies.
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Affiliation(s)
- Zhengping Chen
- Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, China, 214063.
| | - Jie Tang
- Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, China, 214063
| | - Chunyi Liu
- Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, China, 214063
| | - Xiaomin Li
- Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, China, 214063
| | - Hongbo Huang
- Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, China, 214063
| | - Xijie Xu
- Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, China, 214063
| | - Huixin Yu
- Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, China, 214063
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Salo R, Fassbender C. Structural, functional and spectroscopic MRI studies of methamphetamine addiction. Curr Top Behav Neurosci 2015; 11:321-64. [PMID: 22094881 DOI: 10.1007/7854_2011_172] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
This chapter reviews selected neuroimaging findings related to long-term amphetamine and methamphetamine (MA) use. An overview of structural and functional (fMRI) MR studies, Diffusion Tensor Imaging (DTI), Magnetic Resonance Spectroscopy (MRS) and Positron Emission Tomography (PET) studies conducted in long-term MA abusers is presented. The focus of this chapter is to present the relevant studies as tools to understand brain changes following drug abstinence and recovery from addiction. The behavioral relevance of these neuroimaging studies is discussed as they relate to clinical symptoms and treatment. Within each imaging section this chapter includes a discussion of the relevant imaging studies as they relate to patterns of drug use (i.e., duration of MA use, cumulative lifetime dose and time MA abstinent) as well as an overview of studies that link the imaging findings to cognitive measures. In our conclusion we discuss some of the future directions of neuroimaging as it relates to the pathophysiology of addiction.
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Affiliation(s)
- Ruth Salo
- UC Davis Imaging Research Center, 4701 X Street, Sacramento, CA, USA,
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Brain dopaminergic system changes in drug addiction: a review of positron emission tomography findings. Neurosci Bull 2014; 30:765-76. [PMID: 25260796 DOI: 10.1007/s12264-014-1469-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 06/02/2014] [Indexed: 12/31/2022] Open
Abstract
Dopamine (DA) is considered crucial for the rewarding effects of drugs of abuse, but its role in addiction remains unclear. Positron emission tomography (PET) is the first technology used for in vivo measurement of components of the dopaminergic system in the human brain. In this article, we review the major findings from PET imaging studies on the involvement of DA in drug addiction, including presynaptic DA synthesis, vesicular monoamine transporter 2, the DA transporter, and postsynaptic DA receptors. These results have corroborated the role of DA in addiction and increased the understanding of its underlying mechanisms.
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Jan RK, Kydd RR, Russell BR. Functional and structural brain changes associated with methamphetamine abuse. Brain Sci 2012; 2:434-82. [PMID: 24961256 PMCID: PMC4061807 DOI: 10.3390/brainsci2040434] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 09/11/2012] [Accepted: 09/11/2012] [Indexed: 12/20/2022] Open
Abstract
Methamphetamine (MA) is a potent psychostimulant drug whose abuse has become a global epidemic in recent years. Firstly, this review article briefly discusses the epidemiology and clinical pharmacology of methamphetamine dependence. Secondly, the article reviews relevant animal literature modeling methamphetamine dependence and discusses possible mechanisms of methamphetamine-induced neurotoxicity. Thirdly, it provides a critical review of functional and structural neuroimaging studies in human MA abusers; including positron emission tomography (PET) and functional and structural magnetic resonance imaging (MRI). The effect of abstinence from methamphetamine, both short- and long-term within the context of these studies is also reviewed.
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Affiliation(s)
- Reem K Jan
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
| | - Rob R Kydd
- Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
| | - Bruce R Russell
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
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Narendran R, Lopresti BJ, Martinez D, Mason NS, Himes M, May MA, Daley DC, Price JC, Mathis CA, Frankle WG. In vivo evidence for low striatal vesicular monoamine transporter 2 (VMAT2) availability in cocaine abusers. Am J Psychiatry 2012; 169:55-63. [PMID: 22193525 PMCID: PMC3405490 DOI: 10.1176/appi.ajp.2011.11010126] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Positron emission tomography (PET) imaging studies in cocaine abusers have shown that low dopamine release in the striatum following an amphetamine challenge is associated with higher relapse rates. One possible mechanism that might lead to lower amphetamine-induced dopamine release is low availability of dopamine storage vesicles in the presynaptic terminals for release. Consistent with this hypothesis, postmortem studies have shown low levels of vesicular monoamine transporter, type 2 (VMAT2), the membrane protein that regulates the size of the vesicular dopamine pool, in cocaine abusers relative to healthy subjects. To confirm the postmortem findings, the authors used PET and the VMAT2 radioligand [¹¹C]-(+)-dihydrotetrabenazine (DTBZ) to assess the in vivo VMAT2 availability in a group of 12 recently abstinent cocaine-dependent subjects and matched healthy comparison subjects. METHOD [¹¹C]DTBZ nondisplaceable binding potential (BP(ND)) was measured by kinetic analysis using the arterial input function or, if arterial input was unavailable, by the simplified reference tissue method. RESULTS [¹¹C]DTBZ BP(ND) was significantly lower in the cocaine abusers than in the comparison subjects in the limbic striatum (10.0% lower), associative striatum (-13.4%), and sensorimotor striatum (-11.5%). CONCLUSIONS The results of this in vivo PET study confirm previous in vitro reports of low VMAT2 availability in the striatum of cocaine abusers. It also suggests a compensatory down-regulation of the dopamine storage vesicles in response to chronic cocaine abuse and/or a loss of dopaminergic terminals. Further research is necessary to understand the clinical relevance of this observation to relapse and outcome in abstinent cocaine abusers.
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Affiliation(s)
| | | | - Diana Martinez
- Department of Psychiatry, Columbia University Medical Center, New York
| | | | - Michael Himes
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA
| | - Maureen A. May
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA
| | - Dennis C. Daley
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA
| | - Julie C. Price
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA
| | | | - W. Gordon Frankle
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA,Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA
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Wu C, Li R, Dearborn D, Wang Y. Reductive Amination with [<sup>11</sup>C]Formaldehyde: A Versatile Approach to Radiomethylation of Amines. ACTA ACUST UNITED AC 2012. [DOI: 10.4236/ijoc.2012.23030] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Distribution of vesicular monoamine transporter 2 protein in human brain: implications for brain imaging studies. J Cereb Blood Flow Metab 2011; 31:2065-75. [PMID: 21522164 PMCID: PMC3208151 DOI: 10.1038/jcbfm.2011.63] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The choice of reference region in positron emission tomography (PET) human brain imaging of the vesicular monoamine transporter 2 (VMAT2), a marker of striatal dopamine innervation, has been arbitrary, with cerebellar, whole cerebral, frontal, or occipital cortices used. To establish whether levels of VMAT2 are in fact low in these cortical areas, we measured VMAT2 protein distribution by quantitative immunoblotting in autopsied normal human brain (n=6). Four or five species of VMAT2 immunoreactivity (75, 55, 52, 45, 35 kDa) were detected, which were all markedly reduced in intensity in nigrostriatal regions of patients with parkinsonian conditions versus matched controls (n=9 to 10 each). Using the intact VMAT2 immunoreactivity, cerebellar and cerebral neocortices had levels of the transporter >100-fold lower than the VMAT2-rich striatum and with no significant differences among the cortical regions. We conclude that human cerebellar and cerebral cortices contain negligible VMAT2 protein versus the striatum and, in this respect, all satisfy a criterion for a useful reference region for VMAT2 imaging. The slightly lower PET signal for VMAT2 binding in occipital (the currently preferred reference region) versus cerebellar cortex might not therefore be explained by differences in VMAT2 protein itself but possibly by other imaging variables, for example, partial volume effects.
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Saulin A, Savli M, Lanzenberger R. Serotonin and molecular neuroimaging in humans using PET. Amino Acids 2011; 42:2039-57. [PMID: 21947614 DOI: 10.1007/s00726-011-1078-9] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Accepted: 09/05/2011] [Indexed: 02/07/2023]
Abstract
The serotonergic system is one of the most important modulatory neurotransmitter systems in the human brain. It plays a central role in major physiological processes and is implicated in a number of psychiatric disorders. Along with the dopaminergic system, it is also one of the phylogenetically oldest human neurotransmitter systems and one of the most diverse, with 14 different receptors identified up to this day, many of whose function remains to be understood. The system's functioning is even more diverse than the number of its receptors, since each is implicated in a number of different processes. This review aims at illustrating the distribution and summarizing the main functions of the serotonin (5-hydroxytryptamin, 5-HT) receptors as well as the serotonin transporter (SERT, 5-HTT), the vesicular monoamine transporter 2, monoamine oxidase type A and 5-HT synthesis in the human brain. Recent advances in in vivo quantification of these different receptors and enzymes that are part of the serotonergic system using positron emission tomography are described.
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Affiliation(s)
- Anne Saulin
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria
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Eiden LE, Weihe E. VMAT2: a dynamic regulator of brain monoaminergic neuronal function interacting with drugs of abuse. Ann N Y Acad Sci 2011; 1216:86-98. [PMID: 21272013 DOI: 10.1111/j.1749-6632.2010.05906.x] [Citation(s) in RCA: 109] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The monoaminergic neuron, in particular the dopaminergic neuron, is central to mediating the hedonic and addictive properties of drugs of abuse. The effects of amphetamine (AMPH) and cocaine (COC), for example, depend on the ability to increase dopamine in the synapse, by effects on either the plasma membrane transporter DAT or the vesicular transporter for monoamine storage, VMAT2. The potential role of DAT as a target for AMPH and COC has been reviewed extensively. Here, we present VMAT2 as a target that enables the rewarding and addictive actions of these drugs, based on imaging, neurochemical, biochemical, cell biological, genetic, and immunohistochemical evidence. The presence of VMAT2 in noradrenergic, serotoninergic, histaminergic, and potentially trace aminergic neurons invites consideration of a wider role for aminergic neurotransmission in AMPH and COC abuse and addiction.
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Affiliation(s)
- Lee E Eiden
- Section on Molecular Neuroscience, Laboratory of Cellular and Molecular Regulation, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, USA.
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