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Kang S, Jeon S, Lee YG, Ye BS. Dopamine transporter positron emission tomography in patients with Alzheimer's disease with Lewy body disease features. Neurobiol Aging 2024; 134:57-65. [PMID: 37992545 DOI: 10.1016/j.neurobiolaging.2023.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 10/17/2023] [Accepted: 10/18/2023] [Indexed: 11/24/2023]
Abstract
In 36 normal controls (NC), 37 patients with Alzheimer's disease (AD) without parkinsonism (ADP-), 31 AD with parkinsonism (ADP+), and 40 AD with dementia with Lewy bodies (ADDLB), dual-phase dopamine transporter (DAT) positron emission tomography (PET) were performed to evaluate the diagnostic performance of DAT and early-to-delayed uptake ratios (E/Ds) in the anterior caudate (AC), posterior caudate (PC), anterior putamen (AP), posterior putamen (PP), and substantia nigra (SN) to differentiate ADP+/ADDLB from NC, and their effects on parkinsonism and cognition. DAT-SN and E/D-PP showed higher accuracies to differentiate ADP+/ADDLB from NC than DAT-PP. Among AD patients, lower DAT in the putamen and PC and higher E/Ds in the striatum were associated with severe parkinsonism, while higher E/Ds in the putamen, PC, and SN were associated with executive dysfunction. Our results suggest that decreased DAT-SN and increased E/D-PP could be biomarkers differentiating ADP+/ADDLB from pure AD and controls. Meanwhile, increased E/Ds in the putamen could reflect the severity of DLB presenting with parkinsonism and executive dysfunction among AD patients.
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Affiliation(s)
- Sungwoo Kang
- Department of Neurology, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Seun Jeon
- Brain Research Institute, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Young-Gun Lee
- Department of Neurology, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Byoung Seok Ye
- Department of Neurology, Yonsei University College of Medicine, Seoul, Republic of Korea.
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Liu XL, Liu SY, Barret O, Tamagnan GD, Qiao HW, Song TB, Lu J, Chan P. Diagnostic value of striatal 18F-FP-DTBZ PET in Parkinson’s disease. Front Aging Neurosci 2022; 14:931015. [PMID: 35936768 PMCID: PMC9355024 DOI: 10.3389/fnagi.2022.931015] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 06/30/2022] [Indexed: 12/25/2022] Open
Abstract
Background18F-FP-DTBZ has been proven as a biomarker for quantifying the concentration of presynaptic vesicular monoamine transporter 2 (VMAT2). However, its clinical application is still limited.ObjectivesTo evaluate the difference in dopaminergic integrity between patients with Parkinson’s disease (PD) and healthy controls (HC) using 18F-FP-DTBZ PET in vivo and to determine the diagnostic value of standardized uptake value ratios (SUVRs) using the Receiver Operating Characteristic (ROC) curve.MethodsA total of 34 PD and 31 HC participants were enrolled in the PET/MR derivation cohort, while 89 PD and 18 HC participants were recruited in the PET/CT validation cohort. The Hoehn–Yahr Scale and the third part of the MDS-Unified Parkinson’s Disease Rating Scale (MDSUPDRS-III) were used to evaluate the disease staging and severity. All assessments and PET scanning were performed in drug-off states. The striatum was segmented into five subregions as follows: caudate, anterior dorsal putamen (ADP), anterior ventral putamen (AVP), posterior dorsal putamen (PDP), and posterior ventral putamen (PVP) using automatic pipeline built with the PMOD software (version 4.105). The SUVRs of the targeted subregions were calculated using the bilateral occipital cortex as the reference region.ResultsRegarding the diagnostic value, ROC curve and blind validation showed that the contralateral PDP (SUVR = 3.43) had the best diagnostic accuracy (AUC = 0.973; P < 0.05), with a sensitivity of 97.1% (95% CI: 82.9–99.8%), specificity of 100% (95% CI: 86.3–100%), positive predictive value (PPV) of 100% (95% CI: 87.0–100%), negative predictive value (NPV) of 96.9% (95% CI: 82.0–99.8%), and an accuracy of 98.5% for the diagnosis of PD in the derivation cohort. Blind validation of 18F-FP-DTBZ PET imaging diagnosis was done using the PET/CT cohort, where participants with a SUVR of the PDP <3.43 were defined as PD. Kappa test showed a consistency of 0.933 (P < 0.05) between clinical diagnosis and imaging diagnosis, with a sensitivity of 98.9% (95% CI: 93.0–99.9%), specificity of 94.4% (95% CI: 70.6–99.7%), PPV of 98.9% (95% CI: 93.0–99.9%), NPV of 94.4% (95% CI: 70.6–99.7%), and a diagnostic accuracy of 98.1%.ConclusionsOur results showed that an SUVR threshold of 3.43 in the PDP could effectively distinguish patients with PD from HC.
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Affiliation(s)
- Xiu-Lin Liu
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Shu-Ying Liu
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
- Chinese Institute for Brain Research (CIBR), Beijing, China
- Shu-Ying Liu,
| | - Olivier Barret
- CEA, CNRS, MIRCen, Laboratoire des Maladies Neurodégénératives, Université Paris-Saclay, Fontenay-aux-Roses, France
| | - Gilles D. Tamagnan
- Mental Health PET Radioligand Development (MHPRD) Program, Yale University, New Haven, CT, United States
| | - Hong-Wen Qiao
- Department of Radiology and Nuclear Medicine, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Tian-Bin Song
- Department of Radiology and Nuclear Medicine, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Jie Lu
- Department of Radiology and Nuclear Medicine, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Piu Chan
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing, China
- National Clinical Research Center for Geriatric Diseases, Beijing, China
- *Correspondence: Piu Chan,
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Dai Y, Sa R, Guan F, Wang Q, Li Y, Zhao H. A Purification Method of 18F-FP-(+)-DTBZ via Solid-Phase Extraction With Combined Cartridges. Front Med (Lausanne) 2021; 8:693632. [PMID: 34307421 PMCID: PMC8298858 DOI: 10.3389/fmed.2021.693632] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Accepted: 06/17/2021] [Indexed: 11/13/2022] Open
Abstract
Background: To optimize [18F] 9-fluoropropyl-(+)-dihydrotetrabenazine (18F-FP-(+)-DTBZ) purification via solid-phase extraction (SPE) with combined cartridges to facilitate its widespread clinical application. Methods: A modified SPE purification method, employing Sep-Pak PS-2 and Sep-Pak C18 cartridges, was used for the preparation of 18F-FP-(+)-DTBZ. This method was compared to the purification method of high-pressure liquid chromatography (HPLC) and SPE with one cartridge, following quality control test and positron emission tomography (PET) imaging in healthy volunteers and patients with parkinsn's disease (PD). Results: A SPE purification method integrating Sep-Pak PS-2 and Sep-Pak C18 cartridges was implemented successfully. The retention time of 18F-FP-(+)-DTBZ purified by HPLC, SPE with Sep-Pak PS-2, SPE with Sep-Pak C18, and SPE with combined use of Sep-Pak PS-2 and Sep-Pak C18 cartridges was 8.7, 8.8, 8.7, and 8.9 min, respectively. Fewest impurity peak was detected in 18F-FP-(+)-DTBZ purified by the SPE with combined use of Sep-Pak PS-2 and Sep-Pak C18 cartridges. This modified SPE purification method provided a satisfactory radiochemical yield of 29 ± 1.8% with radiochemical purity >99% and shortened synthesis time to 27 min. The brain uptake of 18F-FP-(+)-DTBZ purified by the modified SPE was comparable to that purified by HPLC in both healthy volunteers and PD patients. Conclusions: A SPE method integrating Sep-Pak PS-2 and Sep-Pak C18 cartridges for purification of 18F-FP-(+)-DTBZ may be highly suited to automatic synthesis for routine clinical applications, as it provides excellent radiochemical purity, high yield as well as operational simplicity.
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Affiliation(s)
- Yuyin Dai
- Department of Nuclear Medicine, The First Hospital of Jilin University, Changchun, China
| | - Ri Sa
- Department of Nuclear Medicine, The First Hospital of Jilin University, Changchun, China
| | - Feng Guan
- Department of Nuclear Medicine, The First Hospital of Jilin University, Changchun, China
| | - Qi Wang
- Department of Nuclear Medicine, The First Hospital of Jilin University, Changchun, China
| | - Yinghua Li
- Department of Nuclear Medicine, The First Hospital of Jilin University, Changchun, China
| | - Hongguang Zhao
- Department of Nuclear Medicine, The First Hospital of Jilin University, Changchun, China
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Xu Y, Tang J, Liu C, Zhao C, Cao S, Yu H, Chen Z, Xie M. MicroPET imaging of vesicular monoamine transporter 2 revealed the potentiation of (+)-dihydrotetrabenazine on MPTP-induced degeneration of dopaminergic neurons. Nucl Med Biol 2021; 96-97:9-18. [PMID: 33647803 DOI: 10.1016/j.nucmedbio.2021.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 01/10/2021] [Accepted: 02/11/2021] [Indexed: 10/22/2022]
Abstract
INTRODUCTION Vesicular monoamine transporter 2 (VMAT2) has been associated with the risk of PD. Genetic reduction of VMAT2 level is reported to increase the vulnerability for dopaminergic neurodegeneration. In this study, by using in vivo microPET imaging with a VMAT2 radioligand [18F]fluoropropyl-(+)-dihydrotetrabenazine ([18F]FP-(+)-DTBZ), we investigated the enhanced role of inhibiting VMAT2 in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced loss of dopaminergic neurons. METHODS The (+)-α-dihydrotetrabenazine ((+)-DTBZ, an inhibitor of VMAT2, 5 mg/kg), or MPTP (low dose (ld): 10 mg/kg, high dose (hd): 30 mg/kg) or both of them were intraperitoneally injected into C57BL/6 mice for 5 or 10 consecutive days. MicroPET imaging with [18F]FP-(+)-DTBZ was performed to test the dopaminergic neuronal integrity. [18F]FP-(+)-DTBZ uptake in striatum was quantified as standardized uptake value (SUV). The pathological changes in the striata and substantia nigra were confirmed by measuring the DA contents and immunohistochemical staining of tyrosine hydroxylase (TH). RESULTS In vivo imaging results showed that the striatal SUVs of both DTBZ&MPTPld and MPTPhd groups were substantially declined compared to the baseline. Moreover, the striatal uptakes of [18F]FP-(+)-DTBZ in DTBZ&MPTPld and MPTPhd groups were obviously lower than the control, DTBZ group and MPTPld group. Notably, the decrease of the striatal uptake in the DTBZ&MPTPld/10d group was more serious than the DTBZ&MPTPld/5d group and comparable to the MPTPhd group. Consistently, the ratios of DA metabolites to DA in DTBZ&MPTPld/10d and MPTPhd mice were significantly increased. The correlation analysis showed that SUVs were highly correlated to the striatal dopaminergic fiber density and TH-positive dopaminergic neuron number in the substantia nigra. CONCLUSIONS MicroPET brain imaging with [18F]FP-(+)-DTBZ noninvasively revealed that (+)-DTBZ co-administration significantly aggravated the neurotoxicity of MPTP to dopaminergic neurons, suggesting that inhibition of VMAT2 may be related to the pathogenesis of PD and tracing VMAT2 activity with PET imaging is of potential value in monitoring PD progression.
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Affiliation(s)
- Yingjiao Xu
- NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu 214063, China; Department of Radiopharmaceuticals, School of Pharmacy, Nanjing Medical University, Nanjing 211166, China
| | - Jie Tang
- NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu 214063, China
| | - Chunyi Liu
- NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu 214063, China
| | - Chao Zhao
- NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu 214063, China
| | - Shanshan Cao
- NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu 214063, China
| | - Huixin Yu
- NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu 214063, China
| | - Zhengping Chen
- NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu 214063, China.
| | - Minhao Xie
- NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu 214063, China; Department of Radiopharmaceuticals, School of Pharmacy, Nanjing Medical University, Nanjing 211166, China.
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Kong Y, Zhou H, Feng H, Zhuang J, Wen T, Zhang C, Sun B, Wang J, Guan Y. Elucidating the Relationship Between Diabetes Mellitus and Parkinson's Disease Using 18F-FP-(+)-DTBZ, a Positron-Emission Tomography Probe for Vesicular Monoamine Transporter 2. Front Neurosci 2020; 14:682. [PMID: 32760240 PMCID: PMC7372188 DOI: 10.3389/fnins.2020.00682] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Accepted: 06/03/2020] [Indexed: 01/25/2023] Open
Abstract
Diabetes mellitus (DM) and Parkinson’s disease (PD) have been and will continue to be two common chronic diseases globally that are difficult to diagnose during the prodromal phase. Current molecular genetics, cell biological, and epidemiological evidences have shown the correlation between PD and DM. PD shares the same pathogenesis pathways and pathological factors with DM. In addition, β-cell reduction, which can cause hyperglycemia, is a striking feature of DM. Recent studies indicated that hyperglycemia is highly relevant to the pathologic changes in PD. However, further correlation between DM and PD remains to be investigated. Intriguingly, polycystic monoamine transporter 2 (VMAT2), which is co-expressed in dopaminergic neurons and β cells, is responsible for taking up dopamine into the presynaptic vesicles and can specifically bind to the β cells. Furthermore, we have summarized the specific molecular and diagnostic functions of VMAT2 for the two diseases reported in this review. Therefore, VMAT2 can be applied as a target probe for positron emission tomography (PET) imaging to detect β-cell and dopamine level changes, which can contribute to the diagnosis of DM and PD during the prodromal phase. Targeting VMAT2 with the molecular probe 18F-FP-(+)-DTBZ can be an entry point for the β cell mass (BCM) changes in DM at the molecular level, to clarify the potential relationship between DM and PD. VMAT2 has promising clinical significance in investigating the pathogenesis, early diagnosis, and treatment evaluation of the two diseases.
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Affiliation(s)
- Yanyan Kong
- PET Center, Huashan Hospital, Fudan University, Shanghai, China
| | - Haicong Zhou
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai, China
| | - Hu Feng
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai, China
| | - Junyi Zhuang
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai, China
| | - Tieqiao Wen
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai, China
| | - Chencheng Zhang
- Department of Neurosurgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Bomin Sun
- Department of Neurosurgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jiao Wang
- Laboratory of Molecular Neural Biology, School of Life Sciences, Shanghai University, Shanghai, China
| | - Yihui Guan
- PET Center, Huashan Hospital, Fudan University, Shanghai, China
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Effects of MDPV on dopamine transporter regulation in male rats. Comparison with cocaine. Psychopharmacology (Berl) 2019; 236:925-938. [PMID: 30284596 DOI: 10.1007/s00213-018-5052-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 09/24/2018] [Indexed: 10/28/2022]
Abstract
RATIONALE MDPV (3,4-methylenedioxypyrovalerone) is a synthetic cathinone present in bath salts. It is a powerful psychostimulant and blocker of the dopamine transporter (DAT), like cocaine. It is known that acute exposure to psychostimulants induces rapid changes in DAT function. OBJECTIVES To investigate the effects of MDPV on DAT function comparing with cocaine. METHODS Binding of [3H]WIN 35428 was performed on PC 12 cells treated with MDPV and washed. Rat striatal synaptosomes were incubated with MDPV or cocaine (1 μM) for 1 h and [3H]dopamine (DA) uptake was performed. Also, different treatments with MDPV or cocaine were performed in Sprague-Dawley rats to assess locomotor activity and ex vivo [3H]DA uptake. RESULTS MDPV increased surface [3H]WIN 35428 binding on PC 12 cells. In vitro incubation of synaptosomes with MDPV produced significant increases in Vmax and KM for [3H]DA uptake. In synaptosomes from MDPV- (1.5 mg/kg, s.c.) and cocaine- (30 mg/kg, i.p.) treated rats, there was a significantly higher and more persistent increase in [3H]DA uptake in the case of MDPV than cocaine. Repeated doses of MDPV developed tolerance to this DAT upregulation and 24 h after the 5-day treatment with MDPV, [3H]DA uptake was reduced. However, a challenge with the same drugs after withdrawal recovered the DAT upregulation by both drugs and showed an increased response to MDPV vs the first dose. At the same time, animals were sensitized to the stereotypies induced by both psychostimulants. CONCLUSIONS MDPV induces a rapid and reversible functional upregulation of DAT more powerfully and lasting than cocaine.
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Direct and selective lineage conversion of human fibroblasts to dopaminergic precursors. Neurosci Lett 2019; 699:16-23. [PMID: 30664902 DOI: 10.1016/j.neulet.2019.01.033] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2018] [Revised: 01/16/2019] [Accepted: 01/17/2019] [Indexed: 01/23/2023]
Abstract
Transplantation of dopaminergic precursors (DPs) is a promising therapeutic strategy of Parkinson's disease (PD). However, limited cell source for dopaminergic precursors has become a major obstacle for transplantation therapy. Our group demonstrated previously that mouse fibroblasts can be reprogrammed into induced dopaminergic precursors (iDPs) with high differentiation efficiency. In the current study, we hypothesized that a similar strategy can be applied to generate human iDPs for future cell therapy of PD. We overexpressed transcription factors Brn2, Sox2, and Foxa2 in human fibroblasts and observed formation of neurospheres. Subsequent characterization of the precursor colonies confirmed the generation of human induced dopaminergic precursors (hiDPs). These hiDPs were capable of self-renewal, proliferation, and differentiation. The hiDPs demonstrated high immunoreactivity for neural progenitor markers and high levels of gene expression for ventral mesencephalon-related neural progenitor markers such as Lmx1a, NIKX6.1, Corin, Otx2 and Mash1. Furthermore, the hiDPs could be differentiated into dopaminergic neurons with ˜80% efficiency, which significantly increased major functionally relevant proteins such as TH, DAT, AADC, Lmx1B, and VMAT2 compared to hiDPs. Additionally, hiDPs are more dopaminergic progenitor-restricted compare to those hiDP-like cells reprogrammed only by Brn2 and Sox2. Together, these results suggest that hiDPs with high differentiation efficiency can be generated by direct lineage reprogramming of fibroblasts with transcription factors Brn2, Sox2, and Foxa2. These hiDPs may serve as a safe and effective cell source for transplantation treatment of PD.
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Phan JA, Stokholm K, Zareba-Paslawska J, Jakobsen S, Vang K, Gjedde A, Landau AM, Romero-Ramos M. Early synaptic dysfunction induced by α-synuclein in a rat model of Parkinson's disease. Sci Rep 2017; 7:6363. [PMID: 28743955 PMCID: PMC5526979 DOI: 10.1038/s41598-017-06724-9] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 06/15/2017] [Indexed: 02/08/2023] Open
Abstract
Evidence suggests that synapses are affected first in Parkinson’s disease (PD). Here, we tested the claim that pathological accumulation of α-synuclein, and subsequent synaptic disruption, occur in absence of dopaminergic neuron loss in PD. We determined early synaptic changes in rats that overexpress human α-synuclein by local injection of viral-vectors in midbrain. We aimed to achieve α-synuclein levels sufficient to induce terminal pathology without significant loss of nigral neurons. We tested synaptic disruption in vivo by analyzing motor defects and binding of a positron emission tomography (PET) radioligand to the vesicular monoamine transporter 2, (VMAT2), [11C]dihydrotetrabenazine (DTBZ). Animals overexpressing α-synuclein had progressive motor impairment and, 12 weeks post-surgery, showed asymmetric in vivo striatal DTBZ binding. The PET images matched ligand binding in post-mortem tissue, and histological markers of dopaminergic integrity. Histology confirmed the absence of nigral cell death with concomitant significant loss of striatal terminals. Progressive aggregation of proteinase-K resistant and Ser129-phosphorylated α-synuclein was observed in dopaminergic terminals, in dystrophic swellings that resembled axonal spheroids and contained mitochondria and vesicular proteins. In conclusion, pathological α-synuclein in nigro-striatal axonal terminals leads to early axonal pathology, synaptic disruption, dysfunction of dopaminergic neurotransmission, motor impairment, and measurable change of VMAT2 in the absence of cell loss.
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Affiliation(s)
- Jenny-Ann Phan
- Department of Biomedicine, NEURODIN AU IDEAS Center, Aarhus University, Wilhelm Meyers Allé 4, bldg. 1242, Aarhus C, 8000, Denmark.,Department of Nuclear Medicine and PET Centre, Aarhus University and Hospital, Norrebrogade 44, bldg. 10G, Aarhus C, 8000, Denmark
| | - Kathrine Stokholm
- Department of Biomedicine, NEURODIN AU IDEAS Center, Aarhus University, Wilhelm Meyers Allé 4, bldg. 1242, Aarhus C, 8000, Denmark.,Department of Nuclear Medicine and PET Centre, Aarhus University and Hospital, Norrebrogade 44, bldg. 10G, Aarhus C, 8000, Denmark
| | - Justyna Zareba-Paslawska
- Department of Biomedicine, NEURODIN AU IDEAS Center, Aarhus University, Wilhelm Meyers Allé 4, bldg. 1242, Aarhus C, 8000, Denmark
| | - Steen Jakobsen
- Department of Nuclear Medicine and PET Centre, Aarhus University and Hospital, Norrebrogade 44, bldg. 10G, Aarhus C, 8000, Denmark
| | - Kim Vang
- Department of Nuclear Medicine and PET Centre, Aarhus University and Hospital, Norrebrogade 44, bldg. 10G, Aarhus C, 8000, Denmark
| | - Albert Gjedde
- Department of Neuroscience and Pharmacology, University of Copenhagen, Blegdamsvej 3, Copenhagen, 2200, Denmark.,Center of Neuroscience, University of Copenhagen, Copenhagen, Denmark.,Dept of Radiology & Radiological Science, Johns Hopkins University, Baltimore, MD, USA.,Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada.,Neurosciences Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.,Department of Clinical Medicine, University of Southern Denmark, Odense, Denmark
| | - Anne M Landau
- Department of Nuclear Medicine and PET Centre, Aarhus University and Hospital, Norrebrogade 44, bldg. 10G, Aarhus C, 8000, Denmark. .,Translational Neuropsychiatry Unit, Aarhus University, Skovagervej 2, Risskov, 8240, Denmark.
| | - Marina Romero-Ramos
- Department of Biomedicine, NEURODIN AU IDEAS Center, Aarhus University, Wilhelm Meyers Allé 4, bldg. 1242, Aarhus C, 8000, Denmark.
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Quantitative analysis of the therapeutic effect of magnolol on MPTP-induced mouse model of Parkinson's disease using in vivo 18F-9-fluoropropyl-(+)-dihydrotetrabenazine PET imaging. PLoS One 2017; 12:e0173503. [PMID: 28257461 PMCID: PMC5336287 DOI: 10.1371/journal.pone.0173503] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 02/21/2017] [Indexed: 02/04/2023] Open
Abstract
18F-9-Fluoropropyl-(+)-dihydrotetrabenazine [18F-FP-(+)-DTBZ] positron emission tomography (PET) has been shown to detect dopaminergic neuron loss associated with Parkinson’s disease (PD) in human and neurotoxin-induced animal models. A polyphenol compound, magnolol, was recently proposed as having a potentially restorative effect in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)- or 6-hydroxydopamine-treated animal models. In this study, 18F-FP-(+)-DTBZ PET was used to determine the therapeutic efficacy of magnolol in an MPTP–PD mouse model that was prepared by giving an intraperitoneally (i.p.) daily dose of 25 mg/kg MPTP to male C57BL/6 mice for 5 consecutive days. Twenty-minute static 18F-FP-(+)-DTBZ PET scans were performed before MPTP treatment and 5 days after the termination of MPTP treatment to set up the baseline control. Half of the MPTP-treated mice then received a daily dose of magnolol (10 mg/kg dissolved in corn oil, i.p.) for 6 days. 18F-FP-(+)-DTBZ PET imaging was performed the day after the final treatment. All 18F-FP-(+)-DTBZ PET images were analysed and the specific uptake ratio (SUr) was calculated. Ex vivo autoradiography (ARG) and corresponding immunohistochemistry (IHC) studies were conducted to confirm the distribution of dopaminergic terminals in the striatum. The striatal SUr ratios of 18F-FP-(+)-DTBZ PET images for the Sham, the MPTP, and the MPTP + Magnolol-treated groups were 1.25 ± 0.05, 0.75 ± 0.06, and 1.00 ± 0.11, respectively (n = 4 for each group). The ex vivo 18F-FP-(+)-DTBZ ARG and IHC results correlated favourably with the PET imaging results. 18F-FP-(+)-DTBZ PET imaging suggested that magnolol post-treatment may reverse the neuronal damage in the MPTP-lesioned PD mice. In vivo imaging of the striatal vesicular monoamine transporter type 2 (VMAT2) distribution using 18F-FP-(+)-DTBZ animal PET is a useful method to evaluate the efficacy of therapeutic drugs i.e., magnolol, for the management of PD.
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Kish SJ, Boileau I, Callaghan RC, Tong J. Brain dopamine neurone 'damage': methamphetamine users vs. Parkinson's disease - a critical assessment of the evidence. Eur J Neurosci 2017; 45:58-66. [PMID: 27519465 PMCID: PMC5209286 DOI: 10.1111/ejn.13363] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 07/28/2016] [Accepted: 08/09/2016] [Indexed: 12/31/2022]
Abstract
The objective of this review is to evaluate the evidence that recreational methamphetamine exposure might damage dopamine neurones in human brain, as predicted by experimental animal findings. Brain dopamine marker data in methamphetamine users can now be compared with those in Parkinson's disease, for which the Oleh Hornykiewicz discovery in Vienna of a brain dopamine deficiency is established. Whereas all examined striatal (caudate and putamen) dopamine neuronal markers are decreased in Parkinson's disease, levels of only some (dopamine, dopamine transporter) but not others (dopamine metabolites, synthetic enzymes, vesicular monoamine transporter 2) are below normal in methamphetamine users. This suggests that loss of dopamine neurones might not be characteristic of methamphetamine exposure in at least some human drug users. In methamphetamine users, dopamine loss was more marked in caudate than in putamen, whereas in Parkinson's disease, the putamen is distinctly more affected. Substantia nigra loss of dopamine-containing cell bodies is characteristic of Parkinson's disease, but similar neuropathological studies have yet to be conducted in methamphetamine users. Similarly, it is uncertain whether brain gliosis, a common feature of brain damage, occurs after methamphetamine exposure in humans. Preliminary epidemiological findings suggest that methamphetamine use might increase risk of subsequent development of Parkinson's disease. We conclude that the available literature is insufficient to indicate that recreational methamphetamine exposure likely causes loss of dopamine neurones in humans but does suggest presence of a striatal dopamine deficiency that, in principle, could be corrected by dopamine substitution medication if safety and subject selection considerations can be resolved.
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Affiliation(s)
- Stephen J. Kish
- Human Brain Laboratory, Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Isabelle Boileau
- Addiction Imaging Research Group, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Russell C. Callaghan
- Northern Medical Program, University of Northern British Columbia (UNBC), Prince George, British Columbia, Canada
| | - Junchao Tong
- Human Brain Laboratory, Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Addiction Imaging Research Group, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
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11
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Wile DJ, Sossi V, Stoessl AJ. Reply to letter to the editor: Is there anything more to learn from SWEDD? Mov Disord 2016; 31:1426-8. [PMID: 27519281 DOI: 10.1002/mds.26709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 05/26/2016] [Accepted: 05/26/2016] [Indexed: 11/11/2022] Open
Affiliation(s)
- Daryl J Wile
- Pacific Parkinson's Research Centre, University of British Columbia, British Columbia, Vancouver, Canada.
| | - Vesna Sossi
- Pacific Parkinson's Research Centre, University of British Columbia, British Columbia, Vancouver, Canada.,Department of Physics and Astronomy, University of British Columbia, British Columbia, Vancouver, Canada
| | - A Jon Stoessl
- Pacific Parkinson's Research Centre, University of British Columbia, British Columbia, Vancouver, Canada
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12
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Zimmer L, Breton P, Durand G, Guilloteau D, Besnard J, Chalon S. Prominent Role ofn—3 Polyunsaturated Fatty Acids in Cortical Dopamine Metabolism. Nutr Neurosci 2016; 2:257-65. [DOI: 10.1080/1028415x.1999.11747282] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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13
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McCann UD, Lowe KA, Ricaurte GA. REVIEW ■ : Long-lasting Effects of Recreational Drugs of Abuse on the Central Nervous System. Neuroscientist 2016. [DOI: 10.1177/107385849700300613] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Although a wealth of knowledge exists regarding the acute pharmacological effects of recreational drugs on the CNS, much less is known about the long-term toxic effects of recreational drugs on the CNS. Recent findings in nonhuman primates treated with amphetamine analogs, such as ±3,4-methylenedioxymetham phetamine (MDMA), indicate that these drugs can produce long-lasting, probably permanent, changes in brain serotonin innervation. Similarly, animals treated with phencyclidine (PCP) and related drugs develop neurodegenerative changes in selected brain regions. It seems clear, then, that some psychoactive drugs have the potential to produce persistent changes in CNS structure and, possibly, function. The goal of this article is to summarize current knowledge regarding the long-term effects of several popular recreational drugs, including MDMA and related amphetamine analogs, cocaine, marijuana, alcohol, PCP, lysergic acid (LSD), and opiates. Gaps in the current knowledge base are identified, and areas ripe for future research efforts are suggested. NEUROSCIENTIST 3:399-411, 1997
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Affiliation(s)
- Una D. McCann
- Biological Psychiatry Branch NIMH-IRP Bethesda, Maryland
| | - Kelly A. Lowe
- Department of Neurology Johns Hopkins Medical Institutions
Baltimore, Maryland
| | - George A. Ricaurte
- Department of Neurology Johns Hopkins Medical Institutions
Baltimore, Maryland
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14
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Matthew BJ, Gedzior JS. Drug-induced parkinsonism following chronic methamphetamine use by a patient on haloperidol decanoate. Int J Psychiatry Med 2016; 50:405-11. [PMID: 26526398 DOI: 10.1177/0091217415612736] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
This report attempts to highlight that use of an antipsychotic and concurrent chronic use of methamphetamine can cause drug-induced parkinsonism. Methamphetamine is usually not encountered in the list of agents that induce drug-induced parkinsonism and so its consideration particularly during chronic use by a patient who is also on an antipsychotic is worthwhile because of its popularity as an illegal narcotic. This case report describes just such a case of drug-induced parkinsonism which is a subacute syndrome that mimics Parkinson's disease. Although less alarming than dystonia, it is more common, more difficult to treat and can be the cause of significant disability during maintenance treatment especially in the elderly. In most cases, symptoms are reversible in days or weeks, but occasionally, especially in the elderly, or if long-acting injectable antipsychotics are used-as in this case-symptoms may last for weeks or months. The report also illustrates the neuronal workings due to chronic methamphetamine-use and the additive effects of dopamine blockade by antipsychotics such as haloperidol.
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Affiliation(s)
- Binoj J Matthew
- University of California, San Francisco - Fresno Medical Education Program, Fresno, CA, USA
| | - Joanna S Gedzior
- Department of Psychiatry, VA - Central California Health Care System, Fresno, CA, USA
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15
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Algarni MA, Stoessl AJ. The role of biomarkers and imaging in Parkinson’s disease. Expert Rev Neurother 2016; 16:187-203. [DOI: 10.1586/14737175.2016.1135056] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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16
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Mejias M, Yu J, Mackey S, Dinelle K, Sossi V, Doudet DJ. Interpreting DTBZ binding data in rodent: Inherent variability and compensation. Synapse 2016; 70:147-52. [PMID: 26749375 DOI: 10.1002/syn.21883] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 12/17/2015] [Accepted: 01/04/2016] [Indexed: 12/16/2022]
Abstract
[11C]-dihydrotetrabenazine (DTBZ) Positron Emission Tomography was used to evaluate the vesicular monoamine transporter type 2 as an index of dopaminergic function in the striatum of adult Sprague-Dawley rats obtained from two different animal sources (Charles River Laboratories [CR] or UBC's Animal Care Centre [ACC]) and later submitted to two different unilateral lesions of the nigro-striatal pathway. The results showed a significant difference in the striatal binding potential (BP(ND)) at baseline (before lesioning) between the CR and ACC groups providing evidence that the origin of the animals, possibly due to differences in early environmental factors or breeding conditions associated with different animal vendors plays a role in the development of the adult dopaminergic system. Further, in both animal models, an increase in DTBZ BP(ND) was observed, after unilateral intervention, in the striatum contralateral to the lesion, likely reflecting compensatory effects. Based on these findings, we conclude that in unilateral models, the unlesioned side/hemisphere may not be an appropriate control and that care should be taken to control for the origin of the animals in any given study, especially in longitudinal and replication studies.
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Affiliation(s)
- Miguel Mejias
- Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jing Yu
- Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Nuclear Medicine, Da Lian Medical University Affiliated Hospital No 2, China
| | - Scott Mackey
- Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Psychiatry, University of Vermont, Burlington, Vermont
| | - Katie Dinelle
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - Vesna Sossi
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada
| | - Doris J Doudet
- Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
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17
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McIntosh S, Sexton T, Pattison LP, Childers SR, Hemby SE. Increased Sensitivity to Cocaine Self-Administration in HIV-1 Transgenic Rats is Associated with Changes in Striatal Dopamine Transporter Binding. J Neuroimmune Pharmacol 2015; 10:493-505. [PMID: 25749646 DOI: 10.1007/s11481-015-9594-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 02/13/2015] [Indexed: 12/14/2022]
Abstract
Cocaine abuse in HIV patients accelerates the progression and severity of neuropathology, motor impairment and cognitive dysfunction compared to non-drug using HIV patients. Cocaine and HIV interact with the dopamine transporter (DAT); however, the effect of their interaction on DAT binding remains understudied. The present study compared the dose-response functions for intravenous self-administration of cocaine and heroin between male HIV-1 transgenic (HIV-1 Tg) and Fischer 344 rats. The cocaine and heroin dose-response functions exhibit an inverted U-shape for both HIV-1 Tg and F344 rats. For cocaine, the number of infusions for each dose on the ascending limb was greater for HIV-1 Tg versus F344 rats. No significant changes in the heroin dose-response function were observed in HIV-1 Tg animals. Following the conclusion of self-administration experiments, DAT binding was assessed in striatal membranes. Saturation binding of the cocaine analog [(125)I] 3β-(4-iodophenyl)tropan-2β-carboxylic acid methyl ester ([(125)I]RTI-55) in rat striatal membranes resulted in binding curves that were best fit to a two-site binding model, allowing for calculation of dissociation constant (Kd) and binding density (Bmax) values that correspond to high- and low-affinity DAT binding sites. Control HIV-1 Tg rats exhibited a significantly greater affinity (i.e., decrease in Kd value) in the low-affinity DAT binding site compared to control F344 rats. Furthermore, cocaine self-administration in HIV-1 Tg rats increased low-affinity Kd (i.e., decreased affinity) compared to levels observed in control F344 rats. Cocaine also increased low-affinity Bmax in HIV-1 Tg rats as compared to controls, indicating an increase in the number of low-affinity DAT binding sites. F344 rats did not exhibit any change in high- or low-affinity Kd or Bmax values following cocaine or heroin self-administration. The increase in DAT affinity in cocaine HIV-1 Tg rats is consistent with the leftward shift of the ascending limb of the cocaine dose-response curve observed in HIV-1 Tg vs. F344 rats, and has major implications for the function of cocaine binding to DAT in HIV patients. The absence of HIV-related changes in heroin intake are likely due to less dopaminergic involvement in the mediation of heroin reward, further emphasizing the preferential influence of HIV on dopamine-related behaviors.
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Affiliation(s)
- Scot McIntosh
- Department of Physiology and Pharmacology, Center for the Neurobiology of Addiction Treatment, Winston-Salem, NC, USA
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Narendran R, Jedema HP, Lopresti BJ, Mason NS, Himes ML, Bradberry CW. Decreased vesicular monoamine transporter type 2 availability in the striatum following chronic cocaine self-administration in nonhuman primates. Biol Psychiatry 2015; 77:488-92. [PMID: 25062684 PMCID: PMC4275417 DOI: 10.1016/j.biopsych.2014.06.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 05/13/2014] [Accepted: 06/11/2014] [Indexed: 12/16/2022]
Abstract
BACKGROUND Consistent with postmortem data, in a recent positron emission tomography study, we demonstrated less [(11)C]-(+)-dihydrotetrabenazine ([(11)C]DTBZ) binding to striatal vesicular monoamine transporter type 2 (VMAT2) in cocaine abusers compared with control subjects. A major limitation of these between-group comparison human studies is their inability to establish a causal relationship between cocaine abuse and lower VMAT2. Furthermore, studies in rodents that evaluated VMAT2 binding before and after cocaine self-administration do not support a reduction in VMAT2. METHODS To clarify these discrepant VMAT2 findings and attribute VMAT2 reduction to cocaine abuse, we imaged four rhesus monkeys with [(11)C]DTBZ positron emission tomography before and after 16 months of cocaine self-administration. [(11)C]DTBZ binding potential in the striatum was derived using the simplified reference tissue method with the occipital cortex time activity curve as an input function. RESULTS Chronic cocaine self-administration led to a significant (25.8 ± 7.8%) reduction in [(11)C]DTBZ binding potential. CONCLUSIONS In contrast to the cocaine rodent investigations that do not support alterations in VMAT2, these results in nonhuman primates clearly demonstrated a reduction in VMAT2 binding following prolonged exposure to cocaine. Lower VMAT2 implies that fewer dopamine storage vesicles are available in the presynaptic terminals for release, a likely factor contributing to decreased dopamine transmission in cocaine dependence. Future studies should attempt to clarify the clinical significance of lower VMAT2 in cocaine abusers, for example, its relationship to relapse and vulnerability to mood disorders.
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Affiliation(s)
- Rajesh Narendran
- Department of Radiology; Department of Psychiatry, University of Pittsburgh, Pittsburgh, Pennsylvania.
| | - Hank P. Jedema
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA
| | | | | | - Michael L. Himes
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA
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19
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Lang AE, Miyasaki J, Olanow CW, Stoessl AJ, Suchowersky O. Progress in Clinical Neurosciences: A Forum on the Early Management of Parkinson's Disease. Can J Neurol Sci 2014; 32:277-86. [PMID: 16225167 DOI: 10.1017/s0317167100004145] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
ABSTRACT:There are numerous concerns related to treatment choices involving early dopaminergic therapy in Parkinson's disease. These include the effect on the underlying progression of the neurodegenerative process as well as the development of motor complications such as fluctuations and dyskinesias. A number of recent basic and clinical studies have provided new insights but have also added confusion and controversy. This report summarizes presentations and discussion dealing with these issues from a one-day symposium involving Canadian Movement Disorders neurologists.
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Affiliation(s)
- Anthony E Lang
- Division of Neurology, Department of Medicine, University of Toronto, Toronto Western Hospital, Canada
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20
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Uneven age effects of [18F]FP-CIT binding in the striatum of Parkinson’s disease. Ann Nucl Med 2014; 28:874-9. [DOI: 10.1007/s12149-014-0882-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 07/03/2014] [Indexed: 10/25/2022]
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21
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Calipari ES, Ferris MJ, Melchior JR, Bermejo K, Salahpour A, Roberts DCS, Jones SR. Methylphenidate and cocaine self-administration produce distinct dopamine terminal alterations. Addict Biol 2014; 19:145-55. [PMID: 22458761 DOI: 10.1111/j.1369-1600.2012.00456.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Methylphenidate (MPH) is a commonly abused psychostimulant prescribed for the treatment of attention deficit hyperactivity disorder. MPH has a mechanism of action similar to cocaine (COC) and is commonly characterized as a dopamine transporter (DAT) blocker. While there has been extensive work aimed at understanding dopamine (DA) nerve terminal changes following COC self-administration, very little is known about the effects of MPH self-administration on the DA system. We used fast scan cyclic voltammetry in nucleus accumbens core slices from animals with a 5-day self-administration history of 40 injections/day of either MPH (0.56 mg/kg) or COC (1.5 mg/kg) to explore alterations in baseline DA release and uptake kinetics as well as alterations in the interaction of each compound with the DAT. Although MPH and COC have similar behavioral effects, the consequences of self-administration on DA system parameters were found to be divergent. We show that COC self-administration reduced DAT levels and maximal rates of DA uptake, as well as reducing electrically stimulated release, suggesting decreased DA terminal function. In contrast, MPH self-administration increased DAT levels, DA uptake rates and DA release, suggesting enhanced terminal function, which was supported by findings of increased metabolite/DA tissue content ratios. Tyrosine hydroxylase messenger RNA, protein and phosphorylation levels were also assessed in both groups. Additionally, COC self-administration reduced COC-induced DAT inhibition, while MPH self-administration increased MPH-induced DAT inhibition, suggesting opposite pharmacodynamic effects of these two drugs. These findings suggest that the factors governing DA system adaptations are more complicated than simple DA uptake blockade.
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Affiliation(s)
- Erin S Calipari
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston Salem, NC, USA Department of Pharmacology, University of Toronto, Toronto, Canada
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22
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Hsiao IT, Weng YH, Lin WY, Hsieh CJ, Wey SP, Yen TC, Kung MP, Lu CS, Lin KJ. Comparison of 99mTc-TRODAT-1 SPECT and 18 F-AV-133 PET imaging in healthy controls and Parkinson's disease patients. Nucl Med Biol 2014; 41:322-9. [PMID: 24503330 DOI: 10.1016/j.nucmedbio.2013.12.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 11/27/2013] [Accepted: 12/24/2013] [Indexed: 11/25/2022]
Abstract
UNLABELLED (99m)Tc-TRODAT-1 is the first clinical routine (99m)Tc radiopharmaceutical to evaluate dopamine neurons loss in Parkinson's disease (PD). (18)F-AV-133 is a novel PET radiotracer targeting the vesicular monoamine transporter type 2 (VMAT2) to detect monoaminergic terminal reduction in PD patients. The aim of this study is to compare both images in the same health control (HC) and PD subjects. METHODS Eighteen subjects (8 HC and 10 PD) were recruited for (99m)Tc-TRODAT-1 SPECT, (18)F-AV-133 PET and MRI scans within two weeks. The SPECT images were performed at 4-h post-injection for 45 min, and the PET images were performed at 90 min post-injection for 10 min. Each PET and SPECT image was normalized into Montreal Neurological Institute template aided from individual MRI for comparison. For regional analysis, volume of interest (VOIs) of bilateral caudate nuclei, anterior, posterior putamen and occipital cortex (as reference region) were delineated from the normalized MRI. The specific uptake ratio (SUR) was calculated as (regional mean counts/reference mean counts-1). The nonparametric Mann-Whitney U test was used to evaluate the power of differentiating control from PD subjects for both image modalities. The correlations of the SURs to the clinical parameters were examined. For voxelwise analysis, two-sample t-test for group comparison between HC and PD was computed in both image modalities. RESULTS The SURs of caudate nucleus and putamen correlated well between two image modalities (r = 0.81, p<0.001), and showed significant different between HC and PD subjects. Of note, the (18)F-AV-133 SUR displayed a better correlation to PD clinical laterality index as compared to (99m)Tc-TRODAT-1 (r = 0.73 vs. r = 0.33). Voxelwise analysis showed more lesions for PD subjects from (18)F-AV-133 image as compared to (99m)Tc-TRODAT-1 especially at the substantia nigra region. CONCLUSION (18)F-AV-133 PET demonstrated similar performance in differentiation PD from control, and a better correlation to clinical characteristics than that of (99m)Tc-TRODAT-1 SPECT. (18)F-AV-133 PET also showed additional information in substantia nigra integrity in PD subjects by voxelwise analysis. Collectively, (18)F-AV-133 could be a promising and better tracer for clinical use to detect monoaminergic terminal reduction in PD patients.
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Affiliation(s)
- Ing-Tsung Hsiao
- Healthy Aging Research Center, and Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Molecular Imaging Center and Department of Nuclear Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Yi-Hsin Weng
- Healthy Aging Research Center, and Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Neuroscience Research Center and Section of Movement Disorder, Department of Neurology, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Wey-Yil Lin
- Neuroscience Research Center and Section of Movement Disorder, Department of Neurology, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Chia-Ju Hsieh
- Healthy Aging Research Center, and Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Shiaw-Pyng Wey
- Healthy Aging Research Center, and Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Molecular Imaging Center and Department of Nuclear Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Tzu-Chen Yen
- Healthy Aging Research Center, and Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Molecular Imaging Center and Department of Nuclear Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Mei-Ping Kung
- Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Chin-Song Lu
- Healthy Aging Research Center, and Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Neuroscience Research Center and Section of Movement Disorder, Department of Neurology, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Kun-Ju Lin
- Healthy Aging Research Center, and Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Molecular Imaging Center and Department of Nuclear Medicine, Chang Gung Memorial Hospital, Taoyuan, Taiwan.
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Hauser KF, Knapp PE. Interactions of HIV and drugs of abuse: the importance of glia, neural progenitors, and host genetic factors. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2014; 118:231-313. [PMID: 25175867 PMCID: PMC4304845 DOI: 10.1016/b978-0-12-801284-0.00009-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Considerable insight has been gained into the comorbid, interactive effects of HIV and drug abuse in the brain using experimental models. This review, which considers opiates, methamphetamine, and cocaine, emphasizes the importance of host genetics and glial plasticity in driving the pathogenic neuron remodeling underlying neuro-acquired immunodeficiency syndrome and drug abuse comorbidity. Clinical findings are less concordant than experimental work, and the response of individuals to HIV and to drug abuse can vary tremendously. Host-genetic variability is important in determining viral tropism, neuropathogenesis, drug responses, and addictive behavior. However, genetic differences alone cannot account for individual variability in the brain "connectome." Environment and experience are critical determinants in the evolution of synaptic circuitry throughout life. Neurons and glia both exercise control over determinants of synaptic plasticity that are disrupted by HIV and drug abuse. Perivascular macrophages, microglia, and to a lesser extent astroglia can harbor the infection. Uninfected bystanders, especially astroglia, propagate and amplify inflammatory signals. Drug abuse by itself derails neuronal and glial function, and the outcome of chronic exposure is maladaptive plasticity. The negative consequences of coexposure to HIV and drug abuse are determined by numerous factors including genetics, sex, age, and multidrug exposure. Glia and some neurons are generated throughout life, and their progenitors appear to be targets of HIV and opiates/psychostimulants. The chronic nature of HIV and drug abuse appears to result in sustained alterations in the maturation and fate of neural progenitors, which may affect the balance of glial populations within multiple brain regions.
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Affiliation(s)
- Kurt F Hauser
- Department of Pharmacology & Toxicology, Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, Virginia, USA.
| | - Pamela E Knapp
- Department of Pharmacology & Toxicology, Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, Virginia, USA; Department of Anatomy & Neurobiology, Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, Virginia, USA
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24
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Lin SC, Lin KJ, Hsiao IT, Hsieh CJ, Lin WY, Lu CS, Wey SP, Yen TC, Kung MP, Weng YH. In vivo detection of monoaminergic degeneration in early Parkinson disease by (18)F-9-fluoropropyl-(+)-dihydrotetrabenzazine PET. J Nucl Med 2013; 55:73-9. [PMID: 24287322 DOI: 10.2967/jnumed.113.121897] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
UNLABELLED PET with (18)F-9-fluoropropyl-(+)-dihydrotetrabenzazine ((18)F-DTBZ), a novel radiotracer targeting vesicular monoamine transporter type 2 (VMAT2), has been proven as a useful imaging marker to measure dopaminergic integrity. METHODS The aim of this study was to evaluate the capability of (18)F-DTBZ PET in detecting the monoaminergic degeneration in early Parkinson disease (PD) in vivo. Seventeen age-matched healthy subjects and 30 PD patients at early stage of disease (duration of disease ≤ 5 y) with mild and unilateral motor symptoms underwent (18)F-DTBZ PET scans. The severity of disease, including Unified Parkinson Disease Rating Scale and modified Hoehn and Yahr Stage (mHY), were recorded at off-medication states. The standardized volumes of interest were applied to the spatial normalized image for quantification analysis. The specific uptake ratios (SURs) were calculated according to the formula (specific volumes-of-interest counts/occipital cortex counts) - 1. SUR measurements were summarized for each brain region. RESULTS The mean duration of disease in the PD group was 3.2 ± 2.1 y (range, 0.5-5 y). The mean mHY was 1.0 ± 0.1 (range, 1-1.5). The SURs of bilateral caudate, anterior putamen, posterior putamen, substantia nigra, and nucleus accumbens were significantly lower in PD patients than those of healthy subjects. The reduction of SURs was most severe in the contralateral (the brain regions that are located opposite to the symptomatic side) posterior putamen (-81%), followed by the ipsilateral posterior putamen (-67%). Receiver-operating-characteristic curve analysis showed that the SURs of the bilateral posterior putamen and contralateral anterior putamen had a sensitivity of 100% and specificity of 100% in differentiating PD patients from healthy subjects. CONCLUSION (18)F-DTBZ PET was as an excellent tool for the early diagnosis of PD. The obvious decline of (18)F-DTBZ uptake in the ipsilateral (asymptomatic) striatum suggested that (18)F-DTBZ PET might serve as an in vivo biomarker to detect the monoaminergic degeneration in the premotor phase of PD.
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Affiliation(s)
- Shao-Cheng Lin
- Department of Neurology, Chang Gung Memorial Hospital, Taoyuan, Taiwan
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25
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Motbey CP, Clemens KJ, Apetz N, Winstock AR, Ramsey J, Li KM, Wyatt N, Callaghan PD, Bowen MT, Cornish JL, McGregor IS. High levels of intravenous mephedrone (4-methylmethcathinone) self-administration in rats: neural consequences and comparison with methamphetamine. J Psychopharmacol 2013; 27:823-36. [PMID: 23739178 DOI: 10.1177/0269881113490325] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Mephedrone (MMC) is a relatively new recreational drug that has rapidly increased in popularity in recent years. This study explored the characteristics of intravenous MMC self-administration in the rat, with methamphetamine (METH) used as a comparator drug. Male Sprague-Dawley rats were trained to nose poke for intravenous MMC or METH in daily 2 h sessions over a 10 d acquisition period. Dose-response functions were then established under fixed- and progressive-ratio (FR and PR) schedules over three subsequent weeks of testing. Brains were analyzed ex vivo for striatal serotonin (5-HT) and dopamine (DA) levels and metabolites, while autoradiography assessed changes in the regional density of 5-HT and serotonin transporter (SERT) and DA transporter (DAT) and induction of the inflammation marker translocator protein (TSPO). Results showed that MMC was readily and vigorously self-administered via the intravenous route. Under a FR1 schedule, peak responding for MMC was obtained at 0.1 mg/kg/infusion, versus 0.01 mg/kg/infusion for METH. Break points under a PR schedule peaked at 1 mg/kg/infusion MMC versus 0.3 mg/kg/infusion for METH. Final intakes of MMC were 31.3 mg/kg/d compared to 4 mg/kg/d for METH. Rats self-administering MMC, but not METH, gained weight at a slower rate than control rats. METH, but not MMC, self-administration elevated TSPO receptor density in the nucleus accumbens and hippocampus, while MMC, but not METH, self-administration decreased striatal 5-hydroxyindolacetic acid (5-HIAA) concentrations. In summary, MMC supported high levels of self-administration, matching or exceeding those previously reported with other drugs of abuse.
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Affiliation(s)
- Craig P Motbey
- School of Psychology, University of Sydney, Sydney, Australia
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Gubner NR, Reed C, McKinnon CS, Phillips TJ. Unique genetic factors influence sensitivity to the rewarding and aversive effects of methamphetamine versus cocaine. Behav Brain Res 2013; 256:420-7. [PMID: 23994231 DOI: 10.1016/j.bbr.2013.08.035] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 08/13/2013] [Accepted: 08/19/2013] [Indexed: 11/29/2022]
Abstract
Genetic factors significantly influence addiction-related phenotypes. This is supported by the successful bidirectional selective breeding of two replicate sets of mouse lines for amount of methamphetamine consumed. Some of the same genetic factors that influence methamphetamine consumption have been previously found also to influence sensitivity to the conditioned rewarding and aversive effects of methamphetamine. The goal of the current studies was to determine if some of the same genetic factors influence sensitivity to the conditioned rewarding and aversive effects of cocaine. Cocaine conditioned reward was examined in methamphetamine high drinking and low drinking line mice using a conditioned place preference procedure and cocaine conditioned aversion was measured using a conditioned taste aversion procedure. In addition, a general sensitivity measure, locomotor stimulant response to cocaine, was assessed in these lines; previous data indicated no difference between the selected lines in sensitivity to methamphetamine-induced stimulation. In contrast to robust differences for methamphetamine, the methamphetamine high and low drinking lines did not differ in sensitivity to either the rewarding or aversive effects of cocaine. They also exhibited comparable sensitivity to cocaine-induced locomotor stimulation. These data suggest that the genetic factors that influence sensitivity to the conditioned rewarding and aversive effects of methamphetamine in these lines of mice do not influence sensitivity to these effects of cocaine. Thus, different genetic factors may influence risk for methamphetamine versus cocaine use.
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Affiliation(s)
- Noah R Gubner
- Department of Behavioral Neuroscience and Methamphetamine Abuse Research Center, Oregon Health & Science University, Portland, OR, USA
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Elsworth JD, Redmond DE, Roth RH. Coordinated expression of dopamine transporter and vesicular monoamine transporter in the primate striatum during development. Synapse 2013; 67:580-5. [PMID: 23468413 DOI: 10.1002/syn.21662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Revised: 02/04/2013] [Accepted: 02/24/2013] [Indexed: 11/06/2022]
Abstract
Several addictive or neurotoxic drugs are dependent on the dopamine transporter (DAT) and/or vesicular monoamine transporter (VMAT2) to exert their detrimental effects on dopamine neurons. For example, methamphetamine and MPTP are substrates for both DAT and VMAT2, with the ratio of DAT to VMAT2 in striatum being a determinant of the degree of toxicity inflicted by these drugs on dopamine neurons. Thus, the susceptibility of dopamine neurons to agents whose pharmacology involves DAT and VMAT2 may vary during development if the ontogeny of DAT and VMAT2 differs, and this is relevant as exposure of dopamine neurons to toxic agents during development is hypothesized to underlie some neurological or psychiatric disorders. However, the relative expression of DAT and VMAT2 has not been studied in either primate or nonprimate fetal brain, and this was addressed in the present study by measuring the binding of specific radioligands of DAT and VMAT2 to striatal membranes from nonhuman primates at mid-gestation, late-gestation, and the postnatal and adult periods. Dopamine concentration was also determined in striatal tissue from the same brains. These data indicate that in striatum of primates, unlike rodents, there is a sharp increase in DAT and VMAT2 expression after mid-gestation, with adult levels being attained at the time of birth. In addition, this study demonstrated that there is a coordinated expression of DAT and VMAT2 from the time of mid-gestation to adulthood.
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Affiliation(s)
- John D Elsworth
- Neuropsychopharmacology Research Laboratory, Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut 06511, USA.
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Agarwal PA, Stoessl AJ. Biomarkers for trials of neuroprotection in Parkinson's disease. Mov Disord 2012; 28:71-85. [DOI: 10.1002/mds.25065] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 04/19/2012] [Accepted: 04/23/2012] [Indexed: 02/06/2023] Open
Affiliation(s)
- Pankaj A. Agarwal
- Pacific Parkinson's Research Centre; University of British Columbia; Vancouver; British Columbia; Canada
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Blesa J, Pifl C, Sánchez-González MA, Juri C, García-Cabezas MA, Adánez R, Iglesias E, Collantes M, Peñuelas I, Sánchez-Hernández JJ, Rodríguez-Oroz MC, Avendaño C, Hornykiewicz O, Cavada C, Obeso JA. The nigrostriatal system in the presymptomatic and symptomatic stages in the MPTP monkey model: a PET, histological and biochemical study. Neurobiol Dis 2012; 48:79-91. [PMID: 22677034 DOI: 10.1016/j.nbd.2012.05.018] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2012] [Revised: 05/20/2012] [Accepted: 05/24/2012] [Indexed: 11/19/2022] Open
Abstract
Parkinson's disease (PD) is diagnosed when striatal dopamine (DA) loss exceeds a certain threshold and the cardinal motor features become apparent. The presymptomatic compensatory mechanisms underlying the lack of motor manifestations despite progressive striatal depletion are not well understood. Most animal models of PD involve the induction of a severe dopaminergic deficit in an acute manner, which departs from the typical, chronic evolution of PD in humans. We have used 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) administered to monkeys via a slow intoxication protocol to produce a more gradual development of nigral lesion. Twelve control and 38 MPTP-intoxicated monkeys were divided into four groups. The latter included monkeys who were always asymptomatic, monkeys who recovered after showing mild parkinsonian signs, and monkeys with stable, moderate and severe parkinsonism. We found a close correlation between cell loss in the substantia nigra pars compacta (SNc) and striatal dopaminergic depletion and the four motor states. There was an overall negative correlation between the degree of parkinsonism (Kurlan scale) and in vivo PET ((18)F-DOPA K(i) and (11)C-DTBZ binding potential), as well as with TH-immunoreactive cell counts in SNc, striatal dopaminergic markers (TH, DAT and VMAT2) and striatal DA concentration. This intoxication protocol permits to establish a critical threshold of SNc cell loss and dopaminergic innervation distinguishing between the asymptomatic and symptomatic parkinsonian stages. Compensatory changes in nigrostriatal dopaminergic activity occurred in the recovered and parkinsonian monkeys when DA depletion was at least 88% of control, and accordingly may be considered too late to explain compensatory mechanisms in the early asymptomatic period. Our findings suggest the need for further exploration of the role of non-striatal mechanisms in PD prior to the development of motor features.
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Affiliation(s)
- J Blesa
- Movement Disorders Group, Neurosciences Division, CIMA, and Department of Neurology and Neurosurgery, Clínica Universidad de Navarra, Pamplona, Spain
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Goldberg NR, Fields V, Pflibsen L, Salvatore MF, Meshul CK. Social enrichment attenuates nigrostriatal lesioning and reverses motor impairment in a progressive 1-methyl-2-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of Parkinson's disease. Neurobiol Dis 2012; 45:1051-67. [DOI: 10.1016/j.nbd.2011.12.024] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Revised: 10/29/2011] [Accepted: 12/04/2011] [Indexed: 11/29/2022] Open
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The effect of a novel VMAT2 inhibitor, GZ-793A, on methamphetamine reward in rats. Psychopharmacology (Berl) 2012; 220:395-403. [PMID: 21938414 PMCID: PMC3390966 DOI: 10.1007/s00213-011-2488-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2011] [Accepted: 09/03/2011] [Indexed: 10/17/2022]
Abstract
RATIONALE Previous research suggests that the vesicular monoamine transporter-2 (VMAT2) is a novel target for the treatment of methamphetamine (METH) abuse. OBJECTIVE The effects GZ-793A, a novel, selective, and potent lobelane analog, on the rewarding effects of METH, cocaine, and palatable food in rats were determined. METHOD GZ-793A (3-30 mg/kg, s.c.) was administered 20 min prior to each session in which the groups of rats pressed a lever for infusions of METH (0.03 mg/kg/infusion), cocaine (0.3 mg/kg/infusion), or food pellets. Tolerance to repeated GZ-793A (15 mg/kg, s.c. for 7 days) on METH self-administration and food-maintained responding was determined. The ability of increasing doses of METH (0.001-0.56 mg/kg, i.v.) to surmount inhibition produced by GZ-793A (15 mg/kg, s.c.) was determined. Self-administration of GZ-793A (0.01-0.3 mg/kg/infusion, i.v.) was tested as a substitute for METH infusion. GZ-793A (15 mg/kg, s.c.) was administered 20 min prior to METH or saline conditioning in a place preference test. RESULTS GZ-793A specifically decreased METH self-administration, without the development of tolerance. Increasing the unit dose of METH did not surmount the inhibition produced by GZ-793A on METH self-administration. GZ-793A did not serve as a substitute for self-administered METH. GZ-793A blocked METH-induced conditioned place preference (CPP) and did not induce CPP alone. CONCLUSIONS These results indicate that VMAT2 is a viable target for pharmacological inhibition of METH reward and that GZ-793A represents a new lead in the discovery of a treatment for METH abuse.
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Nandhagopal R, Kuramoto L, Schulzer M, Mak E, Cragg J, McKenzie J, McCormick S, Ruth TJ, Sossi V, de la Fuente-Fernandez R, Stoessl AJ. Longitudinal evolution of compensatory changes in striatal dopamine processing in Parkinson's disease. ACTA ACUST UNITED AC 2012; 134:3290-8. [PMID: 22075521 DOI: 10.1093/brain/awr233] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Parkinson's disease is a relentlessly progressive neurodegenerative disease. Breakdown of compensatory mechanisms influencing putaminal dopamine processing could contribute to the progressive motor symptoms. We studied a cohort of 78 subjects (at baseline) with sporadic Parkinson's disease and 35 healthy controls with multi-tracer positron emission tomography scans to investigate the evolution of adaptive mechanisms influencing striatal dopamine processing in Parkinson's disease progression. Presynaptic dopaminergic integrity was assessed with three radioligands: (i) [(11)C](±)dihydrotetrabenazine, to estimate the density of vesicular monoamine transporter type 2; (ii) [(11)C]d-threo-methylphenidate, to label the dopamine transporter; and (iii) 6-[(18)F]fluoro-L-DOPA, to assess the activity of aromatic amino acid decarboxylase and storage of 6-[(18)F]-fluorodopamine in synaptic vesicles. The subjects with Parkinson's disease and the healthy controls underwent positron emission tomography scans at the initial visit and after 4 and 8 years of follow-up. Non-linear multivariate regression analyses with random effects were utilized to model the longitudinal changes in tracer values in the putamen standardized relative to normal controls. We found evidence for possible upregulation of dopamine synthesis and downregulation of dopamine transporter in the more severely affected putamen in the early stage of Parkinson's disease. The standardized 6-[(18)F]fluoro-L-DOPA and [(11)C]d-threo-methylphenidate values tended to approach [(11)C](±)dihydrotetrabenazine values in the putamen in later stages of disease (i.e. for [(11)C](±)dihydrotetrabenazine values <25% of normal), when the rates of decline in the positron emission tomography measurements were similar for all the markers. Our data suggest that compensatory mechanisms decline as Parkinson's disease progresses. This breakdown of compensatory strategies in the putamen could contribute to the progression of motor symptoms in advanced disease.
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Affiliation(s)
- Ramachandiran Nandhagopal
- Pacific Parkinson's Research Centre, University of British Columbia and Vancouver Coastal Health, Vancouver, BC V6T 2B5, Canada
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Callaghan RC, Cunningham JK, Sykes J, Kish SJ. Increased risk of Parkinson's disease in individuals hospitalized with conditions related to the use of methamphetamine or other amphetamine-type drugs. Drug Alcohol Depend 2012; 120:35-40. [PMID: 21794992 DOI: 10.1016/j.drugalcdep.2011.06.013] [Citation(s) in RCA: 194] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Revised: 06/13/2011] [Accepted: 06/15/2011] [Indexed: 11/30/2022]
Abstract
BACKGROUND Since methamphetamine and other amphetamine-type stimulants (meth/amphetamine) can damage dopaminergic neurons, researchers have long speculated that these drugs may predispose users to develop Parkinson's disease (PD), a dopamine deficiency neurological disorder. METHODS We employed a retrospective population-based cohort study using all linked statewide California inpatient hospital episodes and death records from January 1, 1990 through December 31, 2005. Patients at least 30 years of age were followed for up to 16 years. Competing risks analysis was used to determine whether the meth/amphetamine cohort had elevated risk of developing PD (ICD-9 332.0; ICD-10 G20) in comparison to a matched population-proxy appendicitis group and a matched cocaine drug control group. Individuals admitted to hospital with meth/amphetamine-related conditions (n=40,472; ICD-9 codes 304.4, 305.7, 969.7, E854.2) were matched on age, race, sex, date of index admission, and patterns of hospital admission with patients with appendicitis conditions (n=207,831; ICD-9 codes 540-542) and also individuals with cocaine-use disorders (n=35,335; ICD-9 codes 304.2, 305.6, 968.5). RESULTS The meth/amphetamine cohort showed increased risk of PD compared to both that of the matched appendicitis group [hazard ratio (HR)=1.76, 95% CI: 1.12-2.75, p=0.017] and the matched cocaine group [HR=2.44, 95% CI: 1.32-4.41, p=0.004]. The cocaine group did not show elevated hazard of PD compared to the matched appendicitis group [HR=1.04, 95% CI: 0.56-1.93, p=0.80]. CONCLUSION These data provide evidence that meth/amphetamine users have above-normal risk for developing PD.
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Affiliation(s)
- Russell C Callaghan
- Centre for Addiction and Mental Health, 33 Russell St., Toronto, ON M5S 2S1, Canada.
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Abstract
Advances in imaging have made it possible to detect functional and, increasingly, structural changes in Parkinson's disease. Although imaging is not yet routinely used for diagnosis, such an application is becoming increasingly feasible. Of potentially greater interest, however, is the use of imaging as a biomarker to detect premotor disease and disease progression. Imaging also provides insights into complications of Parkinson's disease and its long-term treatment, and the role of dopamine in the normal brain. Furthermore, these techniques can be applied to animal models, to help validate these models and allow their use in the study of potential disease-modifying therapies.
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Affiliation(s)
- A Jon Stoessl
- Pacific Parkinson's Research Centre, University of British Columbia, Vancouver, BC, Canada.
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Neuroimaging evidence of altered fronto-cortical and striatal function after prolonged cocaine self-administration in the rat. Neuropsychopharmacology 2011; 36:2431-40. [PMID: 21775976 PMCID: PMC3194070 DOI: 10.1038/npp.2011.129] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Cocaine addiction is often modeled in experimental paradigms where rodents learn to self-administer (SA) the drug. However, the extent to which these models replicate the functional alterations observed in clinical neuroimaging studies of cocaine addiction remains unknown. We used magnetic resonance imaging (MRI) to assess basal and evoked brain function in rats subjected to a prolonged, extended-access cocaine SA scheme. Specifically, we measured basal cerebral blood volume (bCBV), an established correlate of basal metabolism, and assessed the reactivity of the dopaminergic system by mapping the pharmacological MRI (phMRI) response evoked by the dopamine-releaser amphetamine. Cocaine-exposed subjects exhibited reduced bCBV in fronto-cortical areas, nucleus accumbens, ventral hippocampus, and thalamus. The cocaine group also showed an attenuated functional response to amphetamine in ventrostriatal areas, an effect that was significantly correlated with total cocaine intake. An inverse relationship between bCBV in the reticular thalamus and the frontal response elicited by amphetamine was found in control subjects but not in the cocaine group, suggesting that the inhibitory interplay within this attentional circuit may be compromised by the drug. Importantly, histopathological analysis did not reveal significant alterations of the microvascular bed in the brain of cocaine-exposed subjects, suggesting that the imaging findings cannot be merely ascribed to cocaine-induced vascular damage. These results document that chronic, extended-access cocaine SA in the rat produces focal fronto-cortical and striatal alterations that serve as plausible neurobiological substrate for the behavioral expression of compulsive drug intake in laboratory animals.
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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: 114] [Impact Index Per Article: 8.8] [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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de la Fuente-Fernández R, Appel-Cresswell S, Doudet DJ, Sossi V. Functional neuroimaging in Parkinson's disease. ACTA ACUST UNITED AC 2011; 5:109-20. [PMID: 23480585 DOI: 10.1517/17530059.2011.554820] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
INTRODUCTION Functional neuroimaging techniques have greatly contributed to improving our understanding of Parkinson's disease (PD) neurodegeneration and related compensatory mechanisms. AREAS COVERED In this paper, the authors analyze the role of functional neuroimaging as a diagnostic tool in PD and review functional neuroimaging studies on PD progression and compensatory adaptations. Through this, the article provides the reader with sensible approaches for the use of functional neuroimaging in the diagnosis of PD. The reader is also provided with knowledge on the time course of nigrostriatal dopamine dysfunction in PD as well as an overview of the potential beneficial and deleterious effects of increased dopamine turnover. Finally, the reader is provided with a critical discussion of the differential effects of levodopa and dopamine agonists on presynaptic dopamine markers and the implications for the interpretation of clinical trials. EXPERT OPINION Functional neuroimaging probably plays a limited role in the diagnosis of PD. Parkinson's disease pathology leads to an exponential decline in nigrostriatal dopamine function and a compensatory increase in dopamine turnover, which may help delay symptom onset. On the negative side, increased dopamine turnover contributes to the development of treatment-related motor complications. Presynaptic markers of dopamine function are subject to regulatory changes, compromising the direct interpretation of neuroimaging results in trials of neuroprotective therapies for PD.
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de la Fuente-Fernández R, Schulzer M, Kuramoto L, Cragg J, Ramachandiran N, Au WL, Mak E, McKenzie J, McCormick S, Sossi V, Ruth TJ, Lee CS, Calne DB, Stoessl AJ. Age-specific progression of nigrostriatal dysfunction in Parkinson's disease. Ann Neurol 2011; 69:803-10. [PMID: 21246604 DOI: 10.1002/ana.22284] [Citation(s) in RCA: 179] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Revised: 08/18/2010] [Accepted: 09/24/2010] [Indexed: 11/06/2022]
Abstract
OBJECTIVE To investigate in vivo the impact of age on nigrostriatal dopamine dysfunction in Parkinson's disease (PD). METHODS PD patients (n = 78) and healthy control subjects (n = 35) underwent longitudinal positron emission tomography assessments using 3 presynaptic dopamine markers: (1) [¹¹C](±)dihydrotetrabenazine (DTBZ), to estimate the density of the vesicular monoamine transporter type 2; (2) [¹¹C]d-threo-methylphenidate, to estimate the density of the plasma membrane dopamine transporter; and (3) 6-[¹⁸F]-fluoro-L-dopa, to estimate the activity of the enzyme dopa-decarboxylase. RESULTS The study comprised 438 PD scans and 241 control scans (679 scans in total). At symptom onset, the loss of putamen DTBZ binding was substantially greater in younger compared to older PD patients (p = 0.015). Remarkably, however, the rate of progression of DTBZ binding loss was significantly slower in younger patients (p < 0.05). The estimated presymptomatic phase of the disease spanned more than 2 decades in younger patients, compared to 1 decade in older patients. INTERPRETATION Our results suggest that, compared to older patients, younger PD patients progress more slowly and are able to endure more damage to the dopaminergic system before the first motor symptoms appear. These observations suggest that younger PD patients have more efficient compensatory mechanisms.
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Okamura N, Villemagne VL, Drago J, Pejoska S, Dhamija RK, Mulligan RS, Ellis JR, Ackermann U, O'Keefe G, Jones G, Kung HF, Pontecorvo MJ, Skovronsky D, Rowe CC. In Vivo Measurement of Vesicular Monoamine Transporter Type 2 Density in Parkinson Disease with 18F-AV-133. J Nucl Med 2010; 51:223-8. [DOI: 10.2967/jnumed.109.070094] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Increased expression of VMAT2 in dopaminergic neurons during nicotine withdrawal. Neurosci Lett 2009; 467:182-6. [PMID: 19835933 DOI: 10.1016/j.neulet.2009.10.038] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Revised: 10/02/2009] [Accepted: 10/08/2009] [Indexed: 11/21/2022]
Abstract
Evidence suggests that the vesicular monoamine transporter-2 (VMAT2) is regulated in striatum and dopamine (DA) may play a role in its regulation. DA is an important mediator of the behavioral actions of nicotine, and dopaminergic neurotransmission is altered following nicotine administration. We investigated the effect of nicotine withdrawal on the expression of VMAT2 in the midbrain DA neurons in animals dependent to nicotine. Mice were injected with nicotine free base 2mg/kg, sc, four times daily for 14 days and killed 12-72h after drug discontinuation. VMAT2 protein was increased in the striatum of nicotine-treated mice in a time-dependent fashion at all times studied. Furthermore, in situ hybridization studies demonstrated that VMAT2 mRNA was elevated in the substantia nigra pars compacta and ventral tegmental area, indicating enhanced gene expression and subsequent protein synthesis. Tissue DA content and synthesis were unaltered in the striatum of nicotine-treated mice at the times studied. However, basal DA release was decreased at 12 and 24h after nicotine discontinuation which coincided with the elevated levels of VMAT2 protein. VMAT2 up-regulation might be a compensatory mechanism to restore and maintain synaptic transmission in dopaminergic midbrain neurons during nicotine withdrawal.
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Kilbourn MR, Butch ER, Desmond T, Sherman P, Harris PE, Frey KA. In vivo [11C]dihydrotetrabenazine binding in rat striatum: sensitivity to dopamine concentrations. Nucl Med Biol 2009; 37:3-8. [PMID: 20122661 DOI: 10.1016/j.nucmedbio.2009.08.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Revised: 08/28/2009] [Accepted: 08/31/2009] [Indexed: 10/20/2022]
Abstract
INTRODUCTION The sensitivity of the in vivo binding of [(11)C]dihydrotetrabenazine ([(11)C]DTBZ) and [(11)C]methylphenidate ([(11)C]MPH) to their respective targets - vesicular monoamine transporter type 2 (VMAT2) and neuronal membrane dopamine transporter - after alterations in endogenous levels of dopamine was examined in the rat brain. METHODS In vivo binding of [(11)C]DTBZ and [(11)C]MPH was determined using a bolus+infusion protocol. The in vitro number of VMAT2 binding sites was determined by autoradiography. RESULTS Repeated dosing with alpha-methyl-p-tyrosine (AMPT) at doses that significantly (-75%) depleted brain tissue dopamine levels resulted in increased (+36%) in vivo [(11)C]DTBZ binding to VMAT2 in the striatum. The increase in binding could be completely reversed via treatment with L-DOPA/benserazide to restore dopamine levels. There were no changes in the total number of VMAT2 binding sites, as measured using in vitro autoradiography. No changes were observed for in vivo [(11)C]MPH binding to the dopamine transporter in the striatum following AMPT pretreatment. CONCLUSION These results indicate that large reductions in dopamine concentrations in the rat brain can produce modest but significant changes in the binding of radioligands to VMAT2, which can be reversed by replenishment of dopamine using exogenous L-DOPA.
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Affiliation(s)
- Michael R Kilbourn
- Department of Radiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
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Kuczenski R, Segal DS, Melega WP, Lacan G, McCunney SJ. Human methamphetamine pharmacokinetics simulated in the rat: behavioral and neurochemical effects of a 72-h binge. Neuropsychopharmacology 2009; 34:2430-41. [PMID: 19571794 PMCID: PMC2778493 DOI: 10.1038/npp.2009.73] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Bingeing is one pattern of high-dose methamphetamine (METH) abuse, which involves continuous drug taking over several days and can result in psychotic behaviors for which the brain pathology remains poorly defined. A corresponding animal model of this type of METH exposure may provide novel insights into the neurochemical and behavioral sequelae associated with this condition. Accordingly, to simulate the pharmacokinetic profile of a human METH binge exposure in rats, we used a computer-controlled, intravenous METH procedure (dynamic infusion, DI) to overcome species differences in METH pharmacokinetics and to replicate the human 12-h plasma METH half-life. Animals were treated over 13 weeks with escalating METH doses, using DI, and then exposed to a binge in which drug was administered every 3 h for 72 h. Throughout the binge, behavioral effects included unabated intense oral stereotypies in the absence of locomotion and in the absence of sleep. Decrements in regional brain dopamine, norepinephrine, and serotonin levels, measured at 1 and 10 h after the last injection of the binge, had, with the exception of caudate-putamen dopamine and frontal cortex serotonin, recovered by 48 h. At 10 h after the last injection of the binge, [(3)H]ligand binding to dopamine and vesicular monoamine transporters in caudate-putamen were reduced by 35 and 13%, respectively. In a separate METH binge-treated cohort, post-binge behavioral alterations were apparent in an attenuated locomotor response to a METH challenge infusion at 24 h after the last injection of the binge. Collectively, the changes we characterized during and after a METH binge suggest that for human beings under similar exposure conditions, multiple time-dependent neurochemical deficits contribute to their behavioral profiles.
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Affiliation(s)
- Ronald Kuczenski
- Department of Psychiatry, School of Medicine, University of California, San Diego, La Jolla, CA 92093-0603, USA.
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Decreased brain dopamine cell numbers in human cocaine users. Psychiatry Res 2009; 168:173-80. [PMID: 19233481 DOI: 10.1016/j.psychres.2008.10.034] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2007] [Revised: 06/24/2008] [Accepted: 10/22/2008] [Indexed: 11/21/2022]
Abstract
Cocaine use diminishes striatal and midbrain dopamine neuronal components in both post-mortem and in vivo human experiments. The diffuse nature of these declines suggests the possibility that cocaine use might cause a loss of dopamine neurons in humans. Previous rodent studies have not detected cocaine-induced dopamine cell damage. The present experiment involved counting midbrain dopamine neurons utilizing both melanin and tyrosine hydroxylase immunoreactivity. Well-preserved blocks ranging from +38 mm obex to +45 mm obex were examined in 10 cocaine users and 9 controls. Sections were also examined for signs of acute pathological injury by counting activated macrophages and microglia. Melanized cells at six midbrain levels were significantly reduced in cocaine users by both drug exposures. The estimated total number of melanized dopamine cells in the anterior midbrain was significantly reduced in cocaine users by 16%. Results with tyrosine hydroxylase immunoreactivity were less conclusive because of variability in staining. Both activated macrophages and activated microglia were significantly increased among cocaine users. Cocaine exposure may have neurotoxic effects on dopamine neurons in humans. The infiltration of phagocytic cells suggests that the lower number of dopamine cells found in cocaine users was a relatively recent effect. The loss of dopamine cells could contribute to and intensify cocaine dependence, as well as anhedonic and depressive symptoms, in some cocaine users. Further efforts at clarifying the pathophysiological mechanisms involved may help explain treatment refractoriness, and identify targets for therapeutic intervention.
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Narendran R, Martinez D. Cocaine abuse and sensitization of striatal dopamine transmission: a critical review of the preclinical and clinical imaging literature. Synapse 2009; 62:851-69. [PMID: 18720516 DOI: 10.1002/syn.20566] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Much effort has been devoted in the preclinical addiction literature to understanding the phenomenon of sensitization, an enhanced dopaminergic response in the nucleus accumbens that occurs after repeated exposure to psychostimulant drugs. Although sensitization has been reported in preclinical studies, studies of sensitization in humans measuring behavioral and physiological responses have been mixed and inconclusive. However, imaging studies with positron emission tomography (PET) and single photon emission computed tomography (SPECT) using a stimulant challenge to induce dopamine (DA) release provide a unique opportunity to probe DA transmission in cocaine dependent human subjects. In contrast to the basic science literature that predicted sensitization, three independent cohorts have shown a blunted DA response, or the opposite of sensitization, in human cocaine dependent subjects. This article reviews the methodological differences between the preclinical and clinical PET studies that have investigated DA sensitization in order to address the discrepancy between the human and animal literature.
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Affiliation(s)
- Rajesh Narendran
- Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania 15232, USA.
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Cruz-Muros I, Afonso-Oramas D, Abreu P, Rodríguez M, González MC, González-Hernández T. Deglycosylation and subcellular redistribution of VMAT2 in the mesostriatal system during normal aging. Neurobiol Aging 2008; 29:1702-11. [PMID: 17582657 DOI: 10.1016/j.neurobiolaging.2007.04.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2006] [Revised: 03/20/2007] [Accepted: 04/04/2007] [Indexed: 10/23/2022]
Abstract
The vesicular monoamine transporter type 2 (VMAT2) is a transmembrane glycoprotein responsible for the vesicular monoamine uptake in the brain. This function declines in the dopaminergic mesostriatal system during normal aging, but the mechanisms responsible for this deficit are unknown. We investigated possible age-related changes in the expression and subcellular distribution of VMAT2 in the rat mesostriatal system. VMAT2 is constitutively expressed as glycosylated (75 kDa), partially glycosylated (55 kDa) and native (45 kDa) forms, they are all present in both synaptosomal compartments (synaptosomal membrane and synaptic vesicle-enriched fractions) of the striatal terminals in young rats. In aged rats, no changes were found in midbrain VMAT2mRNA and VMAT2 total protein levels in whole striatal extracts. However, its subcellular distribution and glycosylation pattern were severely modified. The three VMAT2 forms virtually disappeared from the synaptic vesicle-enriched fraction, while the 55 kDa form was accumulated in the soluble compartment. These changes may be responsible for the loss of VMAT2 activity during aging and may contribute to the high susceptibility of aged midbrain dopaminergic cells to degeneration.
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Affiliation(s)
- Ignacio Cruz-Muros
- Department of Anatomy, Faculty of Medicine, University of La Laguna, 38207 La Laguna, Tenerife, Spain
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Differential cocaine-induced modulation of glutamate and dopamine transporters after contingent and non-contingent administration. Neuropharmacology 2008; 55:771-9. [DOI: 10.1016/j.neuropharm.2008.06.042] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Revised: 06/11/2008] [Accepted: 06/12/2008] [Indexed: 11/16/2022]
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Ferris MJ, Mactutus CF, Booze RM. Neurotoxic profiles of HIV, psychostimulant drugs of abuse, and their concerted effect on the brain: current status of dopamine system vulnerability in NeuroAIDS. Neurosci Biobehav Rev 2008; 32:883-909. [PMID: 18430470 PMCID: PMC2527205 DOI: 10.1016/j.neubiorev.2008.01.004] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2007] [Revised: 01/09/2008] [Accepted: 01/13/2008] [Indexed: 12/21/2022]
Abstract
There are roughly 30-40 million HIV-infected individuals in the world as of December 2007, and drug abuse directly contributes to one-third of all HIV infections in the United States. Antiretroviral therapy has increased the lifespan of HIV-seropositives, but CNS function often remains diminished, effectively decreasing quality of life. A modest proportion may develop HIV-associated dementia, the severity and progression of which is increased with drug abuse. HIV and drugs of abuse in the CNS target subcortical brain structures and DA systems in particular. This toxicity is mediated by a number of neurotoxic mechanisms, including but not limited to, aberrant immune response and oxidative stress. Therefore, novel therapeutic strategies must be developed that can address a wide variety of disparate neurotoxic mechanisms and apoptotic cascades. This paper reviews the research pertaining to the where, what, and how of HIV and cocaine/methamphetamine toxicity in the CNS. Specifically, where these toxins most affect the brain, what aspects of the virus are neurotoxic, and how these toxins mediate neurotoxicity.
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Affiliation(s)
- Mark J Ferris
- University of South Carolina, Program in Behavioral Neuroscience, Columbia, SC 29208, United States.
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Martin WRW, Wieler M, Stoessl AJ, Schulzer M. Dihydrotetrabenazine positron emission tomography imaging in early, untreated Parkinson's disease. Ann Neurol 2008; 63:388-94. [PMID: 18240153 DOI: 10.1002/ana.21320] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE To determine the sensitivity of positron emission tomography with 11C-labeled dihydrotetrabenazine (DTBZ) to the nigrostriatal changes associated with early, untreated Parkinson's disease (PD), and to determine the correlation between any regionally reduced DTBZ binding and the major motor features of PD. METHODS Untreated patients with early PD (n = 27) and age-matched control subjects (n = 33) underwent DTBZ/positron emission tomography scanning to measure binding to the presynaptic type 2 vesicular monoamine transporter site in dopaminergic neurons in basal ganglia regions. Clinical symptoms were rated with the Unified Parkinson's Disease Rating Scale. RESULTS Mean striatal DTBZ binding values in the patient group were decreased as compared with control subjects (p < 0.001) in all regions examined. The difference between patients and control subjects was most marked in the midputamen, where only one patient had DTBZ binding within 3 standard deviations of the control mean. Bradykinesia and rigidity scores correlated with DTBZ binding in the contralateral midputamen region, particularly for the clinically least affected limbs. Tremor scores showed no significant correlation. INTERPRETATION Reduced striatal binding of DTBZ is associated with early PD. Tremor appears to be only partially related to presynaptic dopaminergic function and may have a mechanism differing from that of symptoms such as bradykinesia. The method appears to be most sensitive in mildly affected individuals with a possible "floor" effect that may limit the degree of additional change occurring once more severe clinical symptoms are evident.
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Affiliation(s)
- W R Wayne Martin
- Division of Neurology, University of Alberta, Edmonton, Alberta.
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Sossi V, Holden JE, Topping GJ, Camborde ML, Kornelsen RA, McCormick SE, Greene J, Studenov AR, Ruth TJ, Doudet DJ. In vivo measurement of density and affinity of the monoamine vesicular transporter in a unilateral 6-hydroxydopamine rat model of PD. J Cereb Blood Flow Metab 2007; 27:1407-15. [PMID: 17245418 DOI: 10.1038/sj.jcbfm.9600446] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This is the first in vivo determination of the vesicular monoamine transporter (VMAT2) density (B(max)) and ligand-transporter affinity (K(d)(app)) in six unilaterally 6-hydroxydopamine (6-OHDA) lesioned rats using micro-positron emission tomography (PET) imaging with [(11)C]-(+)-alpha-dihydrotetrabenazine (DTBZ). A multiple ligand concentration transporter assay (MLCTA) was used to determine a B(max) value of 178+/-32 pmol/mL and a K(d)(app) of 47.7+/-9.3 pmol/mL for the non-lesioned side and 30.52+/-5.84 and 43.4+/-15.52 pmol/mL for the lesioned side, respectively. While B(max) was significantly different between the two sides, no significant difference was observed for the K(d)(app). In addition to demonstrating the feasibility of in vivo Scatchard analysis in rats, these data confirm the expectation that a 6-OHDA lesion does not affect the affinity; a much simpler binding potential (BP) measure can thus be used as a marker of lesion severity (LS) in this rat model of Parkinson's disease. A transporter occupancy curve demonstrated negligible transporter occupancy ( approximately 1%) at a specific activity (SA) of 1100 nCi/pmol (assuming an injected dose of 100 microCi/100 g), while 10% occupancy was estimated at 100 nCi/pmol. An indirect measurement indicated that the degree of occupancy as a function of SA is independent of LS. Finally, BP measurement reproducibility was assessed and found to be 11%+/-7% for the healthy and 8%+/-12% for the lesioned side. Quantitative PET results can thus be obtained even for severely lesioned animals with the striatum on one side not clearly visible provided accurate image analysis methods are used.
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Affiliation(s)
- Vesna Sossi
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada.
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