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Masilamoni GJ, Kelly H, Swain AJ, Pare JF, Villalba RM, Smith Y. Structural Plasticity of GABAergic Pallidothalamic Terminals in MPTP-Treated Parkinsonian Monkeys: A 3D Electron Microscopic Analysis. eNeuro 2024; 11:ENEURO.0241-23.2024. [PMID: 38514185 PMCID: PMC10957232 DOI: 10.1523/eneuro.0241-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Revised: 02/22/2024] [Accepted: 02/26/2024] [Indexed: 03/23/2024] Open
Abstract
The internal globus pallidus (GPi) is a major source of tonic GABAergic inhibition to the motor thalamus. In parkinsonism, the firing rate of GPi neurons is increased, and their pattern switches from a tonic to a burst mode, two pathophysiological changes associated with increased GABAergic pallidothalamic activity. In this study, we used high-resolution 3D electron microscopy to demonstrate that GPi terminals in the parvocellular ventral anterior nucleus (VApc) and the centromedian nucleus (CM), the two main GPi-recipient motor thalamic nuclei in monkeys, undergo significant morphometric changes in parkinsonian monkeys including (1) increased terminal volume in both nuclei; (2) increased surface area of synapses in both nuclei; (3) increased number of synapses/GPi terminals in the CM, but not VApc; and (4) increased total volume, but not number, of mitochondria/terminals in both nuclei. In contrast to GPi terminals, the ultrastructure of putative GABAergic nonpallidal terminals was not affected. Our results also revealed striking morphological differences in terminal volume, number/area of synapses, and volume/number of mitochondria between GPi terminals in VApc and CM of control monkeys. In conclusion, GABAergic pallidothalamic terminals are endowed with a high level of structural plasticity that may contribute to the development and maintenance of the abnormal increase in pallidal GABAergic outflow to the thalamus in the parkinsonian state. Furthermore, the evidence for ultrastructural differences between GPi terminals in VApc and CM suggests that morphologically distinct pallidothalamic terminals from single pallidal neurons may underlie specific physiological properties of pallidal inputs to VApc and CM in normal and diseased states.
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Affiliation(s)
- G J Masilamoni
- Emory National Primate Research Center, Atlanta, Georgia 30322
- Udall Center of Excellence for Parkinson's Disease, Emory University, Atlanta, Georgia 30322
| | - H Kelly
- Emory National Primate Research Center, Atlanta, Georgia 30322
- Udall Center of Excellence for Parkinson's Disease, Emory University, Atlanta, Georgia 30322
| | - A J Swain
- Emory National Primate Research Center, Atlanta, Georgia 30322
- Udall Center of Excellence for Parkinson's Disease, Emory University, Atlanta, Georgia 30322
| | - J F Pare
- Emory National Primate Research Center, Atlanta, Georgia 30322
- Udall Center of Excellence for Parkinson's Disease, Emory University, Atlanta, Georgia 30322
| | - R M Villalba
- Emory National Primate Research Center, Atlanta, Georgia 30322
- Udall Center of Excellence for Parkinson's Disease, Emory University, Atlanta, Georgia 30322
| | - Y Smith
- Emory National Primate Research Center, Atlanta, Georgia 30322
- Udall Center of Excellence for Parkinson's Disease, Emory University, Atlanta, Georgia 30322
- Department of Neurology, Emory University, Atlanta, Georgia 30322
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2
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Luyo ZNM, Lawrence AB, Stathopoulos TG, Mitrano DA. Localization and neurochemical identity of alpha1-adrenergic receptor-containing elements in the mouse locus coeruleus. J Chem Neuroanat 2023; 133:102343. [PMID: 37777094 PMCID: PMC10842017 DOI: 10.1016/j.jchemneu.2023.102343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 09/15/2023] [Accepted: 09/25/2023] [Indexed: 10/02/2023]
Abstract
The locus coeruleus (LC) is the major source for norepinephrine (NE) in the brain and projects to areas involved in learning and memory, reward, arousal, attention, and autonomic functions related to stress. There are three types of adrenergic receptors that respond to NE: alpha1-, alpha2-, and beta-adrenergic receptors. Previous behavioral studies have shown the alpha1-adrenergic receptor (α1AR) to be present in the LC, however, with conflicting results. For example, it was shown that α1ARs in the LC are involved in some of the motivational effects of stimulation of the medial forebrain bundle, which was reduced by α1AR antagonist terazosin. Another study showed that during novelty-induced behavioral activation, the α1AR antagonist prazosin reduced c-fos expression in brain regions known to contain motoric α1ARs, except for the LC, where c-fos expression was enhanced. Despite new research delineating more specific connectivity of the neurons in the LC, and some roles of the adrenergic receptors, the α1ARs have not been localized at the subcellular level. Therefore, in order to gain a greater understanding of the aforementioned studies, we used immunohistochemistry at the electron microscopic (EM) level to determine which neuronal or glial elements in the LC express the α1AR. We hypothesized, based on previous work in the ventral periaqueductal gray area, that the α1AR would be found mainly presynaptically in axon terminals, and possibly in glial elements. Single labeling immunohistochemistry at the EM revealed that about 40% of labeled elements that contained the α1AR were glial elements, while approximately 50% of the labeled neuronal elements were axon terminals or small unmyelinated axons in the LC. Double labeling immunohistochemistry found the α1AR expressed in GFAP-labeled astrocytes, in both GABAergic and glutamatergic axon terminals, and in a portion of the α1AR dendrites, colocalized with tyrosine hydroxylase (TH, a marker for noradrenergic neurons). This study sheds light on the neuroanatomical framework underlying the effects of NE and pharmaceuticals acting directly or indirectly on α1ARs in the LC.
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Affiliation(s)
- Zachary N M Luyo
- Program in Neuroscience, Christopher Newport University, Newport News, VA, USA
| | - Abigail B Lawrence
- Program in Neuroscience, Christopher Newport University, Newport News, VA, USA
| | - Theodore G Stathopoulos
- Department of Molecular Biology & Chemistry, Christopher Newport University, Newport News, VA, USA
| | - Darlene A Mitrano
- Program in Neuroscience, Christopher Newport University, Newport News, VA, USA; Department of Molecular Biology & Chemistry, Christopher Newport University, Newport News, VA, USA.
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3
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Allen MI, Duke AN, Nader SH, Adler-Neal A, Solingapuram Sai KK, Reboussin BA, Gage HD, Voll RJ, Mintz A, Goodman MM, Nader MA. PET imaging of dopamine transporters and D2/D3 receptors in female monkeys: effects of chronic cocaine self-administration. Neuropsychopharmacology 2023; 48:1436-1445. [PMID: 37349473 PMCID: PMC10425413 DOI: 10.1038/s41386-023-01622-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 05/22/2023] [Accepted: 05/24/2023] [Indexed: 06/24/2023]
Abstract
Brain imaging studies using positron emission tomography (PET) have shown that long-term cocaine use is associated with lower levels of dopamine (DA) D2/D3 receptors (D2/D3R); less consistent are the effects on DA transporter (DAT) availability. However, most studies have been conducted in male subjects (humans, monkeys, rodents). In this study, we used PET imaging in nine drug-naïve female cynomolgus monkeys to determine if baseline measures of DAT, with [18F]FECNT, and D2/D3R availability, with [11C]raclopride, in the caudate nucleus, putamen and ventral striatum were associated with rates of cocaine self-administration and if these measures changed during long-term (~13 months) cocaine self-administration and following time-off (3-9 months) from cocaine. Cocaine (0.2 mg/kg/injection) and 1.0 g food pellets were available under a multiple fixed-interval (FI) 3-min schedule of reinforcement. In contrast to what has been observed in male monkeys, baseline D2/D3R availability was positively correlated with rates of cocaine self-administration only during the first week of exposure; DAT availability did not correlate with cocaine self-administration. D2/D3R availability decreased ~20% following cumulative intakes of 100 and 1000 mg/kg cocaine; DAT availability did not significantly change. These reductions in D2/D3R availability did not recover over 9 months of time-off from cocaine. To determine if these reductions were reversible, three monkeys were implanted with osmotic pumps that delivered raclopride for 30 days. We found that chronic treatment with the D2/D3R antagonist raclopride increased D2/D3R availability in the ventral striatum but not in the other regions when compared to baseline levels. Over 13 months of self-administration, tolerance did not develop to the rate-decreasing effects of self-administered cocaine on food-reinforced responding, but number of injections and cocaine intake significantly increased over the 13 months. These data extend previous findings to female monkeys and suggest sex differences in the relationship between D2/D3R availability related to vulnerability and long-term cocaine use.
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Affiliation(s)
- Mia I Allen
- Department of Physiology & Pharmacology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC, 27157, USA
| | - Angela N Duke
- Department of Physiology & Pharmacology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC, 27157, USA
| | - Susan H Nader
- Department of Physiology & Pharmacology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC, 27157, USA
| | - Adrienne Adler-Neal
- Department of Physiology & Pharmacology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC, 27157, USA
| | - Kiran K Solingapuram Sai
- Department of Radiology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC, 27157, USA
| | - Beth A Reboussin
- Department of Biostatistics, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC, 27157, USA
| | - H Donald Gage
- Department of Radiology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC, 27157, USA
| | - Ronald J Voll
- Department of Radiology, Emory University School of Medicine, 1515 Dickey Drive, Atlanta, GA, 30322, USA
| | - Akiva Mintz
- Department of Radiology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC, 27157, USA
| | - Mark M Goodman
- Department of Radiology, Emory University School of Medicine, 1515 Dickey Drive, Atlanta, GA, 30322, USA
| | - Michael A Nader
- Department of Physiology & Pharmacology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC, 27157, USA.
- Department of Radiology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC, 27157, USA.
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Masilamoni GJ, Weinkle A, Papa SM, Smith Y. Cortical Serotonergic and Catecholaminergic Denervation in MPTP-Treated Parkinsonian Monkeys. Cereb Cortex 2021; 32:1804-1822. [PMID: 34519330 DOI: 10.1093/cercor/bhab313] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 08/05/2021] [Accepted: 08/07/2021] [Indexed: 11/14/2022] Open
Abstract
Decreased cortical serotonergic and catecholaminergic innervation of the frontal cortex has been reported at early stages of Parkinson's disease (PD). However, the limited availability of animal models that exhibit these pathological features has hampered our understanding of the functional significance of these changes during the course of the disease. In the present study, we assessed longitudinal changes in cortical serotonin and catecholamine innervation in motor-symptomatic and asymptomatic monkeys chronically treated with low doses of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Densitometry and unbiased stereological techniques were used to quantify changes in serotonin and tyrosine hydroxylase (TH) immunoreactivity in frontal cortices of 3 control monkeys and 3 groups of MPTP-treated monkeys (motor-asymptomatic [N = 2], mild parkinsonian [N = 3], and moderate parkinsonian [N = 3]). Our findings revealed a significant decrease (P < 0.001) in serotonin innervation of motor (Areas 4 and 6), dorsolateral prefrontal (Areas 9 and 46), and limbic (Areas 24 and 25) cortical areas in motor-asymptomatic MPTP-treated monkeys. Both groups of symptomatic MPTP-treated animals displayed further serotonin denervation in these cortical regions (P < 0.0001). A significant loss of serotonin-positive dorsal raphe neurons was found in the moderate parkinsonian group. On the other hand, the intensity of cortical TH immunostaining was not significantly affected in motor asymptomatic MPTP-treated monkeys, but underwent a significant reduction in the moderate symptomatic group (P < 0.05). Our results indicate that chronic intoxication with MPTP induces early pathology in the corticopetal serotonergic system, which may contribute to early non-motor symptoms in PD.
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Affiliation(s)
- Gunasingh Jeyaraj Masilamoni
- Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, USA.,Udall Center of Excellence for Parkinson's Disease, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Allison Weinkle
- Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, USA
| | - Stella M Papa
- Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, USA.,Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Yoland Smith
- Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, USA.,Udall Center of Excellence for Parkinson's Disease, Emory University School of Medicine, Atlanta, GA 30322, USA.,Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, USA
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5
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Flace P, Livrea P, Basile GA, Galletta D, Bizzoca A, Gennarini G, Bertino S, Branca JJV, Gulisano M, Bianconi S, Bramanti A, Anastasi G. The Cerebellar Dopaminergic System. Front Syst Neurosci 2021; 15:650614. [PMID: 34421548 PMCID: PMC8375553 DOI: 10.3389/fnsys.2021.650614] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 05/04/2021] [Indexed: 12/04/2022] Open
Abstract
In the central nervous system (CNS), dopamine (DA) is involved in motor and cognitive functions. Although the cerebellum is not been considered an elective dopaminergic region, studies attributed to it a critical role in dopamine deficit-related neurological and psychiatric disorders [e.g., Parkinson's disease (PD) and schizophrenia (SCZ)]. Data on the cerebellar dopaminergic neuronal system are still lacking. Nevertheless, biochemical studies detected in the mammalians cerebellum high dopamine levels, while chemical neuroanatomy studies revealed the presence of midbrain dopaminergic afferents to the cerebellum as well as wide distribution of the dopaminergic receptor subtypes (DRD1-DRD5). The present review summarizes the data on the cerebellar dopaminergic system including its involvement in associative and projective circuits. Furthermore, this study also briefly discusses the role of the cerebellar dopaminergic system in some neurologic and psychiatric disorders and suggests its potential involvement as a target in pharmacologic and non-pharmacologic treatments.
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Affiliation(s)
- Paolo Flace
- Medical School, University of Bari ‘Aldo Moro', Bari, Italy
| | | | - Gianpaolo Antonio Basile
- Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of Messina, Messina, Italy
| | - Diana Galletta
- Unit of Psychiatry and Psychology, Federico II University Hospital, Naples, Italy
| | - Antonella Bizzoca
- Department of Basic Medical Sciences, Neuroscience and Sense Organs, University of Bari “Aldo Moro”, Bari, Italy
| | - Gianfranco Gennarini
- Department of Basic Medical Sciences, Neuroscience and Sense Organs, University of Bari “Aldo Moro”, Bari, Italy
| | - Salvatore Bertino
- Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of Messina, Messina, Italy
| | | | - Massimo Gulisano
- Department of Experimental and Clinical Medicine, University of Firenze, Firenze, Italy
| | - Simona Bianconi
- Physical, Rehabilitation Medicine and Sport Medicine Unit, University Hospital “G. Martino”, Messina, Italy
| | - Alessia Bramanti
- Scientific Institute for Research, Hospitalization and Health Care IRCCS “Centro Neurolesi Bonino Pulejo”, Messina, Italy
| | - Giuseppe Anastasi
- Department of Biomedical, Dental Sciences and Morphological and Functional Images, University of Messina, Messina, Italy
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6
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Villalba RM, Behnke JA, Pare JF, Smith Y. Comparative Ultrastructural Analysis of Thalamocortical Innervation of the Primary Motor Cortex and Supplementary Motor Area in Control and MPTP-Treated Parkinsonian Monkeys. Cereb Cortex 2021; 31:3408-3425. [PMID: 33676368 PMCID: PMC8599722 DOI: 10.1093/cercor/bhab020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 12/29/2020] [Accepted: 01/19/2021] [Indexed: 12/15/2022] Open
Abstract
The synaptic organization of thalamic inputs to motor cortices remains poorly understood in primates. Thus, we compared the regional and synaptic connections of vGluT2-positive thalamocortical glutamatergic terminals in the supplementary motor area (SMA) and the primary motor cortex (M1) between control and MPTP-treated parkinsonian monkeys. In controls, vGluT2-containing fibers and terminal-like profiles invaded layer II-III and Vb of M1 and SMA. A significant reduction of vGluT2 labeling was found in layer Vb, but not in layer II-III, of parkinsonian animals, suggesting a potential thalamic denervation of deep cortical layers in parkinsonism. There was a significant difference in the pattern of synaptic connectivity in layers II-III, but not in layer Vb, between M1 and SMA of control monkeys. However, this difference was abolished in parkinsonian animals. No major difference was found in the proportion of perforated versus macular post-synaptic densities at thalamocortical synapses between control and parkinsonian monkeys in both cortical regions, except for a slight increase in the prevalence of perforated axo-dendritic synapses in the SMA of parkinsonian monkeys. Our findings suggest that disruption of the thalamic innervation of M1 and SMA may underlie pathophysiological changes of the motor thalamocortical loop in the state of parkinsonism.
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Affiliation(s)
- Rosa M Villalba
- Division of Neuropharmacology and Neurological Diseases, Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, USA
- UDALL Center for Excellence for Parkinson’s Disease, Emory University, Atlanta, GA 30329, USA
| | - Joseph A Behnke
- Division of Neuropharmacology and Neurological Diseases, Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, USA
- UDALL Center for Excellence for Parkinson’s Disease, Emory University, Atlanta, GA 30329, USA
| | - Jean-Francois Pare
- Division of Neuropharmacology and Neurological Diseases, Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, USA
- UDALL Center for Excellence for Parkinson’s Disease, Emory University, Atlanta, GA 30329, USA
| | - Yoland Smith
- Division of Neuropharmacology and Neurological Diseases, Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, USA
- UDALL Center for Excellence for Parkinson’s Disease, Emory University, Atlanta, GA 30329, USA
- Department of Neurology, School of Medicine, Emory University, Atlanta, GA 30329, USA
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7
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Microglia, inflammation and gut microbiota responses in a progressive monkey model of Parkinson's disease: A case series. Neurobiol Dis 2020; 144:105027. [PMID: 32712266 DOI: 10.1016/j.nbd.2020.105027] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 07/13/2020] [Accepted: 07/20/2020] [Indexed: 12/29/2022] Open
Abstract
Inflammation has been linked to the development of nonmotor symptoms in Parkinson's disease (PD), which greatly impact patients' quality of life and can often precede motor symptoms. Suitable animal models are critical for our understanding of the mechanisms underlying disease and the associated prodromal disturbances. The neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated monkey model is commonly seen as a "gold standard" model that closely mimics the clinical motor symptoms and the nigrostriatal dopaminergic loss of PD, however MPTP toxicity extends to other nondopaminergic regions. Yet, there are limited reports monitoring the MPTP-induced progressive central and peripheral inflammation as well as other nonmotor symptoms such as gastrointestinal function and microbiota. We report 5 cases of progressive parkinsonism in non-human primates to gain a broader understanding of MPTP-induced central and peripheral inflammatory dysfunction to understand the potential role of inflammation in prodromal/pre-motor features of PD-like degeneration. We measured inflammatory proteins in plasma and CSF and performed [18F]FEPPA PET scans to evaluate translocator proteins (TSPO) or microglial activation. Monkeys were also evaluated for working memory and executive function using various behavior tasks and for gastrointestinal hyperpermeability and microbiota composition. Additionally, monkeys were treated with a novel TNF inhibitor XPro1595 (10 mg/kg, n = 3) or vehicle (n = 2) every three days starting 11 weeks after the initiation of MPTP to determine whether XPro1595 would alter inflammation and microglial behavior in a progressive model of PD. The case studies revealed that earlier and robust [18F]FEPPA PET signals resulted in earlier and more severe parkinsonism, which was seen in male cases compared to female cases. Potential other sex differences were observed in circulating inflammation, microbiota diversity and their metabolites. Additional studies with larger group sizes of both sexes would enable confirmation and extension of these findings. If these findings reflect potential differences in humans, these sex differences have significant implications for therapeutic development of inflammatory targets in the clinic.
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Swain AJ, Galvan A, Wichmann T, Smith Y. Structural plasticity of GABAergic and glutamatergic networks in the motor thalamus of parkinsonian monkeys. J Comp Neurol 2019; 528:1436-1456. [PMID: 31808567 DOI: 10.1002/cne.24834] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 11/10/2019] [Accepted: 11/19/2019] [Indexed: 12/20/2022]
Abstract
In the primate thalamus, the parvocellular ventral anterior nucleus (VApc) and the centromedian nucleus (CM) receive GABAergic projections from the internal globus pallidus (GPi) and glutamatergic inputs from motor cortices. In this study, we used electron microscopy to assess potential structural changes in GABAergic and glutamatergic microcircuits in the VApc and CM of MPTP-treated parkinsonian monkeys. The intensity of immunostaining for GABAergic markers in VApc and CM did not differ between control and parkinsonian monkeys. In the electron microscope, three major types of terminals were identified in both nuclei: (a) vesicular glutamate transporter 1 (vGluT1)-positive terminals forming asymmetric synapses (type As), which originate from the cerebral cortex, (b) GABAergic terminals forming single symmetric synapses (type S1), which likely arise from the reticular nucleus and GABAergic interneurons, and (c) GABAergic terminals forming multiple symmetric synapses (type S2), which originate from GPi. The density of As terminals outnumbered that of S1 and S2 terminals in VApc and CM of control and parkinsonian animals. No significant change was found in the abundance and synaptic connectivity of S1 and S2 terminals in VApc or CM of MPTP-treated monkeys, while the prevalence of "As" terminals in VApc of parkinsonian monkeys was 51.4% lower than in controls. The cross-sectional area of vGluT1-positive boutons in both VApc and CM of parkinsonian monkeys was significantly larger than in controls, but their pattern of innervation of thalamic cells was not altered. Our findings suggest that the corticothalamic system undergoes significant synaptic remodeling in the parkinsonian state.
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Affiliation(s)
- Ashley J Swain
- Division of Neuropharmacology and Neurological Disorders, Yerkes National Primate Research Center, Atlanta, Georgia.,Udall Center of Excellence for Parkinson's Disease Research, Atlanta, Georgia
| | - Adriana Galvan
- Division of Neuropharmacology and Neurological Disorders, Yerkes National Primate Research Center, Atlanta, Georgia.,Udall Center of Excellence for Parkinson's Disease Research, Atlanta, Georgia.,Department of Neurology, School of Medicine, Emory University, Atlanta, Georgia
| | - Thomas Wichmann
- Division of Neuropharmacology and Neurological Disorders, Yerkes National Primate Research Center, Atlanta, Georgia.,Udall Center of Excellence for Parkinson's Disease Research, Atlanta, Georgia.,Department of Neurology, School of Medicine, Emory University, Atlanta, Georgia
| | - Yoland Smith
- Division of Neuropharmacology and Neurological Disorders, Yerkes National Primate Research Center, Atlanta, Georgia.,Udall Center of Excellence for Parkinson's Disease Research, Atlanta, Georgia.,Department of Neurology, School of Medicine, Emory University, Atlanta, Georgia
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9
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Villalba RM, Pare JF, Lee S, Lee S, Smith Y. Thalamic degeneration in MPTP-treated Parkinsonian monkeys: impact upon glutamatergic innervation of striatal cholinergic interneurons. Brain Struct Funct 2019; 224:3321-3338. [PMID: 31679085 PMCID: PMC6878768 DOI: 10.1007/s00429-019-01967-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 10/04/2019] [Indexed: 12/13/2022]
Abstract
In both Parkinson's disease (PD) patients and MPTP-treated non-human primates, there is a profound neuronal degeneration of the intralaminar centromedian/parafascicular (CM/Pf) thalamic complex. Although this thalamic pathology has long been established in PD (and other neurodegenerative disorders), the impact of CM/Pf cell loss on the integrity of the thalamo-striatal glutamatergic system and its regulatory functions upon striatal neurons remain unknown. In the striatum, cholinergic interneurons (ChIs) are important constituents of the striatal microcircuitry and represent one of the main targets of CM/Pf-striatal projections. Using light and electron microscopy approaches, we have analyzed the potential impact of CM/Pf neuronal loss on the anatomy of the synaptic connections between thalamic terminals (vGluT2-positive) and ChIs neurons in the striatum of parkinsonian monkeys treated chronically with MPTP. The following conclusions can be drawn from our observations: (1) as reported in PD patients, and in our previous monkey study, CM/Pf neurons undergo profound degeneration in monkeys chronically treated with low doses of MPTP. (2) In the caudate (head and body) nucleus of parkinsonian monkeys, there is an increased density of ChIs. (3) Despite the robust loss of CM/Pf neurons, no significant change was found in the density of thalamostriatal (vGluT2-positive) terminals, and in the prevalence of vGluT2-positive terminals in contact with ChIs in parkinsonian monkeys. These findings provide new information about the state of thalamic innervation of the striatum in parkinsonian monkeys with CM/Pf degeneration, and bring up an additional level of intricacy to the consequences of thalamic pathology upon the functional microcircuitry of the thalamostriatal system in parkinsonism. Future studies are needed to assess the importance of CM/Pf neuronal loss, and its potential consequences on the neuroplastic changes induced in the synaptic organization of the thalamostriatal system, in the development of early cognitive impairments in PD.
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Affiliation(s)
- Rosa M Villalba
- Division of Neuropharmacology and Neurological Diseases, Yerkes National Primate Research Center, Emory University, 954, Gatewood Rd NE, Atlanta, GA, 303, USA.
- UDALL Center for Excellence for Parkinson's Disease, Emory University, Atlanta, GA, USA.
| | - Jean-Francois Pare
- Division of Neuropharmacology and Neurological Diseases, Yerkes National Primate Research Center, Emory University, 954, Gatewood Rd NE, Atlanta, GA, 303, USA
- UDALL Center for Excellence for Parkinson's Disease, Emory University, Atlanta, GA, USA
| | - Solah Lee
- Division of Neuropharmacology and Neurological Diseases, Yerkes National Primate Research Center, Emory University, 954, Gatewood Rd NE, Atlanta, GA, 303, USA
- UDALL Center for Excellence for Parkinson's Disease, Emory University, Atlanta, GA, USA
| | - Sol Lee
- Division of Neuropharmacology and Neurological Diseases, Yerkes National Primate Research Center, Emory University, 954, Gatewood Rd NE, Atlanta, GA, 303, USA
- UDALL Center for Excellence for Parkinson's Disease, Emory University, Atlanta, GA, USA
| | - Yoland Smith
- Division of Neuropharmacology and Neurological Diseases, Yerkes National Primate Research Center, Emory University, 954, Gatewood Rd NE, Atlanta, GA, 303, USA
- Department of Neurology, School of Medicine, Emory University, Atlanta, GA, USA
- UDALL Center for Excellence for Parkinson's Disease, Emory University, Atlanta, GA, USA
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10
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Masilamoni GJ, Smith Y. Chronic MPTP administration regimen in monkeys: a model of dopaminergic and non-dopaminergic cell loss in Parkinson's disease. J Neural Transm (Vienna) 2017; 125:337-363. [PMID: 28861737 DOI: 10.1007/s00702-017-1774-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 07/29/2017] [Indexed: 12/17/2022]
Abstract
Parkinson's disease (PD) is a progressive neurodegenerative disorder clinically characterized by cardinal motor deficits including bradykinesia, tremor, rigidity and postural instability. Over the past decades, it has become clear that PD symptoms extend far beyond motor signs to include cognitive, autonomic and psychiatric impairments, most likely resulting from cortical and subcortical lesions of non-dopaminergic systems. In addition to nigrostriatal dopaminergic degeneration, pathological examination of PD brains, indeed, reveals widespread distribution of intracytoplasmic inclusions (Lewy bodies) and death of non-dopaminergic neurons in the brainstem and thalamus. For that past three decades, the MPTP-treated monkey has been recognized as the gold standard PD model because it displays some of the key behavioral and pathophysiological changes seen in PD patients. However, a common criticism raised by some authors about this model, and other neurotoxin-based models of PD, is the lack of neuronal loss beyond the nigrostriatal dopaminergic system. In this review, we argue that this assumption is largely incorrect and solely based on data from monkeys intoxicated with acute administration of MPTP. Work achieved in our laboratory and others strongly suggest that long-term chronic administration of MPTP leads to brain pathology beyond the dopaminergic system that displays close similarities to that seen in PD patients. This review critically examines these data and suggests that the chronically MPTP-treated nonhuman primate model may be suitable to study the pathophysiology and therapeutics of some non-motor features of PD.
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Affiliation(s)
- Gunasingh J Masilamoni
- Yerkes National Primate Research Center, Emory University, 954, Gatewood Rd NE, Atlanta, GA, 30322, USA.
- Udall Center of Excellence for Parkinson's Disease, Emory University, 954, Gatewood Rd NE, Atlanta, GA, 30322, USA.
| | - Yoland Smith
- Yerkes National Primate Research Center, Emory University, 954, Gatewood Rd NE, Atlanta, GA, 30322, USA
- Department of Neurology, Emory University, 954, Gatewood Rd NE, Atlanta, GA, 30322, USA
- Udall Center of Excellence for Parkinson's Disease, Emory University, 954, Gatewood Rd NE, Atlanta, GA, 30322, USA
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11
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Xu S, Liu Y, Li Y, Deng Y, Yuan J, Lv R, Wang Y, Zhang G, Guo Z, Fu D, Zeng H, Han M, Liu X. Availability of dopamine transporters in heroin-dependent subjects: A 18F-FECNT PET imaging study. Psychiatry Res Neuroimaging 2017; 263:121-126. [PMID: 28376406 DOI: 10.1016/j.pscychresns.2017.03.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 03/21/2017] [Accepted: 03/24/2017] [Indexed: 10/19/2022]
Abstract
This study was to reconfirm the reduced dopamine transporter (DAT) availability in heroin-dependent subjects and validate the use of 2β-carbomethoxy-3β-(4-chlorophenyl)-8-(2-fluoroethyl)-nortropane (18F-FECNT) as a PET radiotracer to assess the changes of striatal DAT in drug addicted subjects. Herein, we assessed DAT standardized uptake values (SUV) of 18F-FECNT in the striatum and cerebellum of 20 heroin-dependent subjects and 10 healthy controls and analyzed the correlation between DAT availability and heroin withdrawal symptom scores and anxiety/depression rating scales in heroin-dependent subjects, as well as the relationship between the withdrawal symptoms scores and age. The striatal DAT availability in heroin-dependent subjects was significantly lower (by ~15.7-17.6%) than that in healthy controls. Age was positively related to heroin withdrawal symptom scores. The withdrawal symptom scores in older patients (Age: 49.5±2.5) were significantly higher (by ~20%) than those in younger patients (Age: 30.9±4.8). These results confirm that chronic heroin use induces striatal DAT reduction, suggesting that 18F-FECNT could be used as an alternative PET imaging radioligand for in vivo imaging of DAT in drug addicted subjects. Moreover, older patients might suffer more severe withdrawal symptoms than younger patients, suggesting that older patients with heroin withdrawal could be given more medication.
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Affiliation(s)
- Shasha Xu
- Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, China; Department of Nuclear Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Ying Liu
- Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, China
| | - Yu Li
- Drug Rehabilitation Center, Shanghai, China
| | - Yangping Deng
- National Institute on Drug Dependence, Peking University, Beijing, China
| | - Jie Yuan
- Department of Nuclear Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Rongbin Lv
- Department of Nuclear Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Yuankai Wang
- Department of Nuclear Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Guangming Zhang
- Department of Nuclear Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Zhirui Guo
- Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, China
| | - Daxu Fu
- Shanghai Center of Biomedicine Development, Shanghai, China
| | - Hui Zeng
- Beijing LADO Technology Company, Beijing, China
| | - Mei Han
- Key Laboratory of Radiopharmaceuticals, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, China.
| | - Xingdang Liu
- Department of Nuclear Medicine, Huashan Hospital, Fudan University, Shanghai, China.
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12
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Masilamoni GJ, Groover O, Smith Y. Reduced noradrenergic innervation of ventral midbrain dopaminergic cell groups and the subthalamic nucleus in MPTP-treated parkinsonian monkeys. Neurobiol Dis 2016; 100:9-18. [PMID: 28042095 DOI: 10.1016/j.nbd.2016.12.025] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 12/22/2016] [Accepted: 12/28/2016] [Indexed: 02/07/2023] Open
Abstract
There is anatomical and functional evidence that ventral midbrain dopaminergic (DA) cell groups and the subthalamic nucleus (STN) receive noradrenergic innervation in rodents, but much less is known about these interactions in primates. Degeneration of NE neurons in the locus coeruleus (LC) and related brainstem NE cell groups is a well-established pathological feature of Parkinson's disease (PD), but the development of such pathology in animal models of PD has been inconsistent across species and laboratories. We recently demonstrated 30-40% neuronal loss in the LC, A5 and A6 NE cell groups of rhesus monkeys rendered parkinsonian by chronic administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). In this study, we used dopamine-beta-hydroxylase (DβH) immunocytochemistry to assess the impact of this neuronal loss on the number of NE terminal-like varicosities in the substantia nigra pars compacta (SNC), ventral tegmental area (VTA), retrorubral field (RRF) and STN of MPTP-treated parkinsonian monkeys. Our findings reveal that the NE innervation of the ventral midbrain and STN of normal monkeys is heterogeneously distributed being far more extensive in the VTA, RRF and dorsal tier of the SNC than in the ventral SNC and STN. In parkinsonian monkeys, all regions underwent a significant (~50-70%) decrease in NE innervation. At the electron microscopic level, some DβH-positive terminals formed asymmetric axo-dendritic synapses in VTA and STN. These findings demonstrate that the VTA, RRF and SNCd are the main ventral midbrain targets of ascending NE inputs, and that these connections undergo a major break-down in chronically MPTP-treated parkinsonian monkeys. This severe degeneration of the ascending NE system may contribute to the pathophysiology of ventral midbrain and STN neurons in PD.
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Affiliation(s)
- Gunasingh Jeyaraj Masilamoni
- Yerkes National Primate Research Center, Emory University, 954, Gatewood Rd NE, Atlanta, GA 30322, USA; Udall Center of Excellence for Parkinson's Disease, Emory University, 954, Gatewood Rd NE, Atlanta, GA 30322, USA.
| | - Olivia Groover
- Yerkes National Primate Research Center, Emory University, 954, Gatewood Rd NE, Atlanta, GA 30322, USA; Department of Neurology, Emory University, 954, Gatewood Rd NE, Atlanta, GA 30322, USA.
| | - Yoland Smith
- Yerkes National Primate Research Center, Emory University, 954, Gatewood Rd NE, Atlanta, GA 30322, USA; Department of Neurology, Emory University, 954, Gatewood Rd NE, Atlanta, GA 30322, USA; Udall Center of Excellence for Parkinson's Disease, Emory University, 954, Gatewood Rd NE, Atlanta, GA 30322, USA.
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13
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Asakawa T, Fang H, Sugiyama K, Nozaki T, Hong Z, Yang Y, Hua F, Ding G, Chao D, Fenoy AJ, Villarreal SJ, Onoe H, Suzuki K, Mori N, Namba H, Xia Y. Animal behavioral assessments in current research of Parkinson's disease. Neurosci Biobehav Rev 2016; 65:63-94. [PMID: 27026638 DOI: 10.1016/j.neubiorev.2016.03.016] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 03/22/2016] [Accepted: 03/22/2016] [Indexed: 12/21/2022]
Abstract
Parkinson's disease (PD), a neurodegenerative disorder, is traditionally classified as a movement disorder. Patients typically suffer from many motor dysfunctions. Presently, clinicians and scientists recognize that many non-motor symptoms are associated with PD. There is an increasing interest in both motor and non-motor symptoms in clinical studies on PD patients and laboratory research on animal models that imitate the pathophysiologic features and symptoms of PD patients. Therefore, appropriate behavioral assessments are extremely crucial for correctly understanding the mechanisms of PD and accurately evaluating the efficacy and safety of novel therapies. This article systematically reviews the behavioral assessments, for both motor and non-motor symptoms, in various animal models involved in current PD research. We addressed the strengths and weaknesses of these behavioral tests and their appropriate applications. Moreover, we discussed potential mechanisms behind these behavioral tests and cautioned readers against potential experimental bias. Since most of the behavioral assessments currently used for non-motor symptoms are not particularly designed for animals with PD, it is of the utmost importance to greatly improve experimental design and evaluation in PD research with animal models. Indeed, it is essential to develop specific assessments for non-motor symptoms in PD animals based on their characteristics. We concluded with a prospective view for behavioral assessments with real-time assessment with mobile internet and wearable device in future PD research.
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Affiliation(s)
- Tetsuya Asakawa
- Department of Neurosurgery, Hamamatsu University School of Medicine, Hamamatsu-city, Shizuoka, Japan; Department of Psychiatry, Hamamatsu University School of Medicine, Hamamatsu-city, Shizuoka, Japan.
| | - Huan Fang
- Department of Pharmacy, Jinshan Hospital of Fudan University, Shanghai, China
| | - Kenji Sugiyama
- Department of Neurosurgery, Hamamatsu University School of Medicine, Hamamatsu-city, Shizuoka, Japan
| | - Takao Nozaki
- Department of Neurosurgery, Hamamatsu University School of Medicine, Hamamatsu-city, Shizuoka, Japan
| | - Zhen Hong
- Department of Neurology, Huashan Hospital of Fudan University, Shanghai, China
| | - Yilin Yang
- The First People's Hospital of Changzhou, Soochow University School of Medicine, Changzhou, China
| | - Fei Hua
- The First People's Hospital of Changzhou, Soochow University School of Medicine, Changzhou, China
| | - Guanghong Ding
- Shanghai Key Laboratory of Acupuncture Mechanism and Acupoint Function, Fudan University, Shanghai, China
| | - Dongman Chao
- Department of Neurosurgery, The University of Texas McGovern Medical School,Houston, TX, USA
| | - Albert J Fenoy
- Department of Neurosurgery, The University of Texas McGovern Medical School,Houston, TX, USA
| | - Sebastian J Villarreal
- Department of Neurosurgery, The University of Texas McGovern Medical School,Houston, TX, USA
| | - Hirotaka Onoe
- Functional Probe Research Laboratory, RIKEN Center for Life Science Technologies, Kobe, Japan
| | - Katsuaki Suzuki
- Department of Psychiatry, Hamamatsu University School of Medicine, Hamamatsu-city, Shizuoka, Japan
| | - Norio Mori
- Department of Psychiatry, Hamamatsu University School of Medicine, Hamamatsu-city, Shizuoka, Japan
| | - Hiroki Namba
- Department of Neurosurgery, Hamamatsu University School of Medicine, Hamamatsu-city, Shizuoka, Japan
| | - Ying Xia
- Department of Neurosurgery, The University of Texas McGovern Medical School,Houston, TX, USA.
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Yun JW, Ahn JB, Kwon E, Ahn JH, Park HW, Heo H, Park JS, Kim H, Paek SH, Kang BC. Behavior, PET and histology in novel regimen of MPTP marmoset model of Parkinson's disease for long-term stem cell therapy. Tissue Eng Regen Med 2015; 13:100-109. [PMID: 30603390 DOI: 10.1007/s13770-015-0106-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 11/09/2015] [Accepted: 11/13/2015] [Indexed: 12/21/2022] Open
Abstract
Stem cell technologies are particularly attractive in Parkinson's disease (PD) research although they occasionally need long-term treatment for anti-parkinsonian activity. Unfortunately, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) widely used as a model for PD has several limitations, including the risk of dose-dependent mortality and the difficulty of maintenance of PD symptoms during the whole experiment period. Therefore, we tested if our novel MPTP regimen protocol (2 mg/kg for 2 consecutive days and 1 mg/kg for next 3 consecutive days) can be maintained stable parkinsonism without mortality for long-term stem cell therapy. For this, we used small-bodied common marmoset monkeys (Callithrix jacchus) among several nonhuman primates showing high anatomical, functional, and behavioral similarities to humans. Along with no mortality, the behavioral changes involved in PD symptoms were maintained for 32 weeks. Also, the loss of jumping ability of the MPTP-treated marmosets in the Tower test was not recovered by 32 weeks. Positron emission tomography (PET) analysis revealed that remarkable decreases of bindings of 18F-FP-CIT were observed at the striatum of the brains of the marmosets received MPTP during the full period of the experiment for 32 weeks. In the substantia nigra of the marmosets, the loss of tyrosine hydroxylase (TH) immunoreactivity was also observed at 32 weeks following the MPTP treatment. In conclusion, our low-dose MPTP regimen protocol was found to be stable parkinsonism without mortality as evidenced by behavior, PET, and TH immunohistochemistry. This result will be useful for evaluation of possible long-term stem cell therapy for anti-parkinsonian activity.
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Affiliation(s)
- Jun-Won Yun
- 1Department of Experimental Animal Research, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea
| | - Jae-Bum Ahn
- 1Department of Experimental Animal Research, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea.,2Graduate School of Translational Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Euna Kwon
- 1Department of Experimental Animal Research, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea
| | - Jae Hun Ahn
- 1Department of Experimental Animal Research, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea.,2Graduate School of Translational Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Hyung Woo Park
- 3Department of Neurosurgery, Seoul National University College of Medicine, Seoul, Korea
| | - Hwon Heo
- 4Department of Biomedical Sciences, Seoul National University, Seoul, Korea
| | - Jin-Sung Park
- 5Department of Neurogenetics, Kolling Institute of Medical Research, Royal North Shore Hospital and the University of Sydney, St. Leonards, New South Wales, Australia
| | - Hyeonjin Kim
- 4Department of Biomedical Sciences, Seoul National University, Seoul, Korea.,6Department of Radiology, Seoul National University Hospital, Seoul, Korea
| | - Sun Ha Paek
- 3Department of Neurosurgery, Seoul National University College of Medicine, Seoul, Korea
| | - Byeong-Cheol Kang
- 1Department of Experimental Animal Research, Biomedical Research Institute, Seoul National University Hospital, Seoul, Korea.,2Graduate School of Translational Medicine, Seoul National University College of Medicine, Seoul, Korea.,7Designed Animal and Transplantation Research Institute, Institute of GreenBio Science Technology, Seoul National University, Pyeongchang, Korea
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15
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Differential Alterations of Dopamine Transporter in the Striatum and Midbrain in Patients With Parkinsonian Syndrome. Clin Nucl Med 2015; 40:191-4. [DOI: 10.1097/rlu.0000000000000638] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Lin X, Shi M, Masilamoni JG, Dator R, Movius J, Aro P, Smith Y, Zhang J. Proteomic profiling in MPTP monkey model for early Parkinson disease biomarker discovery. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1854:779-87. [PMID: 25617661 DOI: 10.1016/j.bbapap.2015.01.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 01/09/2015] [Accepted: 01/16/2015] [Indexed: 01/02/2023]
Abstract
Identification of reliable and robust biomarkers is crucial to enable early diagnosis of Parkinson disease (PD) and monitoring disease progression. While imperfect, the slow, chronic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced non-human primate animal model system of parkinsonism is an abundant source of pre-motor or early stage PD biomarker discovery. Here, we present a study of a MPTP rhesus monkey model of PD that utilizes complementary quantitative iTRAQ-based proteomic, glycoproteomics and phosphoproteomics approaches. We compared the glycoprotein, non-glycoprotein, and phosphoprotein profiles in the putamen of asymptomatic and symptomatic MPTP-treated monkeys as well as saline injected controls. We identified 86 glycoproteins, 163 non-glycoproteins, and 71 phosphoproteins differentially expressed in the MPTP-treated groups. Functional analysis of the data sets inferred the biological processes and pathways that link to neurodegeneration in PD and related disorders. Several potential biomarkers identified in this study have already been translated for their usefulness in PD diagnosis in human subjects and further validation investigations are currently under way. In addition to providing potential early PD biomarkers, this comprehensive quantitative proteomic study may also shed insights regarding the mechanisms underlying early PD development. This article is part of a Special Issue entitled: Neuroproteomics: Applications in neuroscience and neurology.
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Affiliation(s)
- Xiangmin Lin
- Department of Pathology, University of Washington School of Medicine, Seattle, WA, USA; School of Life Sciences, Fujian Agricultural and Forestry University, Fuzhou, Fujian, China
| | - Min Shi
- Department of Pathology, University of Washington School of Medicine, Seattle, WA, USA
| | | | - Romel Dator
- Department of Pathology, University of Washington School of Medicine, Seattle, WA, USA
| | - James Movius
- Department of Pathology, University of Washington School of Medicine, Seattle, WA, USA
| | - Patrick Aro
- Department of Pathology, University of Washington School of Medicine, Seattle, WA, USA
| | - Yoland Smith
- Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA; Department of Neurology, Emory University, Atlanta, GA, USA
| | - Jing Zhang
- Department of Pathology, University of Washington School of Medicine, Seattle, WA, USA.
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Joshi EM, Need A, Schaus J, Chen Z, Benesh D, Mitch C, Morton S, Raub TJ, Phebus L, Barth V. Efficiency gains in tracer identification for nuclear imaging: can in vivo LC-MS/MS evaluation of small molecules screen for successful PET tracers? ACS Chem Neurosci 2014; 5:1154-63. [PMID: 25247893 DOI: 10.1021/cn500073j] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Positron emission tomography (PET) imaging has become a useful noninvasive technique to explore molecular biology within living systems; however, the utility of this method is limited by the availability of suitable radiotracers to probe specific targets and disease biology. Methods to identify potential areas of improvement in the ability to predict small molecule performance as tracers prior to radiolabeling would speed the discovery of novel tracers. In this retrospective analysis, we characterized the brain penetration or peak SUV (standardized uptake value), binding potential (BP), and brain exposure kinetics across a series of known, nonradiolabeled PET ligands using in vivo LC-MS/MS (liquid chromatography coupled to mass spectrometry) and correlated these parameters with the reported PET ligand performance in nonhuman primates and humans available in the literature. The PET tracers studied included those reported to label G protein-coupled receptors (GPCRs), intracellular enzymes, and transporters. Additionally, data for each tracer was obtained from a mouse brain uptake assay (MBUA), previously published, where blood-brain barrier (BBB) penetration and clearance parameters were assessed and compared against similar data collected on a broad compound set of central nervous system (CNS) therapeutic compounds. The BP and SUV identified via nonradiolabeled LC-MS/MS, while different from the published values observed in the literature PET tracer data, allowed for an identification of initial criteria values we sought to facilitate increased potential for success from our early discovery screening paradigm. Our analysis showed that successful, as well as novel, clinical PET tracers exhibited BP of greater than 1.5 and peak SUVs greater than approximately 150% at 5 min post dose in rodents. The brain kinetics appeared similar between both techniques despite differences in tracer dose, suggesting linearity across these dose ranges. The assessment of tracers in a CNS exposure model, the mouse brain uptake assessment (MBUA), showed that those compound with initial brain-to-plasma ratios >2 and unbound fraction in brain homogenate >0.01 were more likely to be clinically successful PET ligands. Taken together, early incorporation of a LC/MS/MS cold tracer discovery assay and a parallel MBUA can be an useful screening paradigm to prioritize and rank order potential novel PET radioligands during early tracer discovery efforts. Compounds considered for continued in vivo PET assessments can be identified quickly by leveraging in vitro affinity and selectivity measures, coupled with data from a MBUA, primarily the 5 min brain-to-plasma ratio and unbound fraction data. Coupled utilization of these data creates a strategy to efficiently screen for the identification of appropriate chemical space to invest in for radiotracer discovery.
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Affiliation(s)
- Elizabeth M. Joshi
- Eli Lilly and Co., Lilly Research Laboratories, Indianapolis, Indiana 46285, United States
| | - Anne Need
- Eli Lilly and Co., Lilly Research Laboratories, Indianapolis, Indiana 46285, United States
| | - John Schaus
- Eli Lilly and Co., Lilly Research Laboratories, Indianapolis, Indiana 46285, United States
| | - Zhaogen Chen
- Eli Lilly and Co., Lilly Research Laboratories, Indianapolis, Indiana 46285, United States
| | - Dana Benesh
- Eli Lilly and Co., Lilly Research Laboratories, Indianapolis, Indiana 46285, United States
| | - Charles Mitch
- Eli Lilly and Co., Lilly Research Laboratories, Indianapolis, Indiana 46285, United States
| | - Stuart Morton
- Eli Lilly and Co., Lilly Research Laboratories, Indianapolis, Indiana 46285, United States
| | - Thomas J. Raub
- Eli Lilly and Co., Lilly Research Laboratories, Indianapolis, Indiana 46285, United States
| | - Lee Phebus
- Eli Lilly and Co., Lilly Research Laboratories, Indianapolis, Indiana 46285, United States
| | - Vanessa Barth
- Eli Lilly and Co., Lilly Research Laboratories, Indianapolis, Indiana 46285, United States
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Wu X, Cai H, Ge R, Li L, Jia Z. Recent progress of imaging agents for Parkinson's disease. Curr Neuropharmacol 2014; 12:551-63. [PMID: 25977680 PMCID: PMC4428027 DOI: 10.2174/1570159x13666141204221238] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 11/22/2014] [Accepted: 12/02/2014] [Indexed: 02/05/2023] Open
Abstract
Parkinson's disease (PD) is a common progressive, neurodegenerative brain disease that is promoted by mitochondrial dysfunction, oxidative stress, protein aggregation and proteasome dysfunction in the brain. Compared with computer tomography (CT) or magnetic resonance imaging (MRI), non-invasive nuclear radiopharmaceuticals have great significance for the early diagnosis of PD due to their high sensitivity and specificity in atypical and preclinical cases. Based on the development of coordination chemistry and chelator design, radionuclides may be delivered to lesions by attaching to PD-related transporters and receptors, such as dopamine, serotonin, and others. In this review, we comprehensively detailed the current achievements in radionuclide imaging in Parkinson's disease.
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Affiliation(s)
- Xiaoai Wu
- Department of Nuclear Medicine, West China Hospital of Sichuan University, Chengdu, P.R. China
| | - Huawei Cai
- Department of Nuclear Medicine, West China Hospital of Sichuan University, Chengdu, P.R. China
| | - Ran Ge
- Department of Nuclear Medicine, Fujian Medical University Union Hospital, Fuzhou, P.R. China
| | - Lin Li
- Department of Nuclear Medicine, West China Hospital of Sichuan University, Chengdu, P.R. China
| | - Zhiyun Jia
- Department of Nuclear Medicine, West China Hospital of Sichuan University, Chengdu, P.R. China
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Shin HW, Kim JS, Oh M, You S, Kim YJ, Kim J, Kim MJ, Chung SJ. Clinical features of drug-induced parkinsonism based on [18F] FP-CIT positron emission tomography. Neurol Sci 2014; 36:269-74. [PMID: 25231645 DOI: 10.1007/s10072-014-1945-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 09/05/2014] [Indexed: 11/30/2022]
Abstract
Drug-induced parkinsonism (DIP) is the common cause of parkinsonism. It is difficult to make a differentiation between DIP and Parkinson's disease (PD) because there are no notable differences in the clinical characteristics between the two entities. In this study, we examined the relationship between the characteristics of [(18)F] fluorinated-N-3-fluoropropyl-2-β-carboxymethoxy-3-β-(4-iodophenyl)nortropane (FP-CIT) positron emission tomography (PET) images and clinical features in DIP patients. We retrospectively studied 76 patients with DIP who underwent [(18)F] FP-CIT PET. We also enrolled 16 healthy controls who underwent it. We compared the clinical characteristics between the DIP patients with normal [(18)F] FP-CIT PET scans and those with abnormal ones. Symmetric parkinsonism was more frequent in the patients with normal [(18)F] FP-CIT PET scans as compared with those with abnormal ones. Interval from drug intake to onset of parkinsonism was longer in the patients with abnormal [(18)F] FP-CIT PET scans as compared with those with normal ones. A semi-quantitative analysis showed that specific to non-specific binding ratios in the putamen was lower in the patients with abnormal [(18)F] FP-CIT PET scans as compared with those with normal ones and the age-matched control group. Our results suggest that symmetric parkinsonism was more prevalent, and the duration of drug exposure before the onset of parkinsonism was shorter in the patients with normal [(18)F] FP-CIT PET scans as compared with those with abnormal ones.
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Affiliation(s)
- Hae-Won Shin
- Department of Neurology, Chung-Ang University College of Medicine, Seoul, Korea
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20
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Vezoli J, Dzahini K, Costes N, Wilson CRE, Fifel K, Cooper HM, Kennedy H, Procyk E. Increased DAT binding in the early stage of the dopaminergic lesion: a longitudinal [11C]PE2I binding study in the MPTP-monkey. Neuroimage 2014; 102 Pt 2:249-61. [PMID: 25108180 DOI: 10.1016/j.neuroimage.2014.07.059] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2014] [Revised: 07/24/2014] [Accepted: 07/30/2014] [Indexed: 12/13/2022] Open
Abstract
The delayed appearance of motor symptoms in PD poses a crucial challenge for early detection of the disease. We measured the binding potential of the selective dopamine active transporter (DAT) radiotracer [(11)C]PE2I in MPTP-treated macaque monkeys, thus establishing a detailed profile of the nigrostriatal DA status following MPTP intoxication and its relation to induced motor and non-motor symptoms. Clinical score and cognitive performance were followed throughout the study. We measured longitudinally in vivo the non-displaceable binding potential to DAT in premotor, motor-recovered (i.e. both non-symptomatic) and symptomatic MPTP-treated monkeys. Results show an unexpected and pronounced dissociation between clinical scores and [(11)C]PE2I-BP(ND) during the premotor phase i.e. DAT binding in the striatum of premotor animals was increased around 20%. Importantly, this broad increase of DAT binding in the caudate, ventral striatum and anterior putamen was accompanied by i) deteriorated cognitive performance, showing a likely causal role of the observed hyperdopaminergic state (Cools, 2011; Cools and D'Esposito, 2011) and ii) an asymmetric decrease of DAT binding at a focal point of the posterior putamen, suggesting that increased DAT is one of the earliest, intrinsic compensatory mechanisms. Following spontaneous recovery from motor deficits, DAT binding was greatly reduced as recently shown in-vivo with other radiotracers (Blesa et al., 2010, 2012). Finally, high clinical scores were correlated to considerably low levels of DAT only after the induction of a stable parkinsonian state. We additionally show that the only striatal region which was significantly correlated to the degree of motor impairments is the ventral striatum. Further research on this period should allow better understanding of DA compensation at premature stages of PD and potentially identify new diagnosis and therapeutic index.
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Affiliation(s)
- Julien Vezoli
- INSERM U846, Stem Cell and Brain Research Institute, Bron, France; Université de Lyon, Université Lyon1, Lyon, France.
| | - Kwamivi Dzahini
- INSERM U846, Stem Cell and Brain Research Institute, Bron, France; Université de Lyon, Université Lyon1, Lyon, France; Primastem (LifeStemCells), Bron, France
| | | | - Charles R E Wilson
- INSERM U846, Stem Cell and Brain Research Institute, Bron, France; Université de Lyon, Université Lyon1, Lyon, France
| | - Karim Fifel
- INSERM U846, Stem Cell and Brain Research Institute, Bron, France; Université de Lyon, Université Lyon1, Lyon, France
| | - Howard M Cooper
- INSERM U846, Stem Cell and Brain Research Institute, Bron, France; Université de Lyon, Université Lyon1, Lyon, France
| | - Henry Kennedy
- INSERM U846, Stem Cell and Brain Research Institute, Bron, France; Université de Lyon, Université Lyon1, Lyon, France
| | - Emmanuel Procyk
- INSERM U846, Stem Cell and Brain Research Institute, Bron, France; Université de Lyon, Université Lyon1, Lyon, France
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Tian L, Karimi M, Brown CA, Loftin SK, Perlmutter JS. In vivo measures of nigrostriatal neuronal response to unilateral MPTP treatment. Brain Res 2014; 1571:49-60. [PMID: 24845719 DOI: 10.1016/j.brainres.2014.05.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 05/08/2014] [Accepted: 05/09/2014] [Indexed: 01/01/2023]
Abstract
A single unilateral intracarotid infusion of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) into non-human primates causes injury to the nigrostriatal pathway including nigral cell bodies, axons and striatal terminal fields. In this model, motor parkinsonism correlates well with the loss of nigral dopaminergic cell bodies but only correlates with in vitro measures of nigrostriatal terminal fields when nigral cell loss does not exceed 50%. The goals of this study are to determine the relationship of motor parkinsonism with the degree of injury to nigrostriatal axons, as reflected by in vitro fiber length density measures, and compare in vivo with in vitro measures of striatal terminal fields. We determined axon integrity by measuring fiber length density with tyrosine hydroxylase (TH) immunohistology and dopamine transporter (DAT) density with DAT immunohistology. We then calculated the terminal arbor size and compared these measures with previously published data of quantified in vivo positron emission tomography (PET) measures of presynaptic dopaminergic neurons, autoradiographic measures of DAT and vesicular monoamine transporter type 2 (VMAT2), striatal dopamine, nigral cell counts, and parkinsonian motor ratings in the same animals. Our data demonstrate that in vivo and in vitro measures of striatal terminal fields correlate with each other regardless of the method of measurement. PET-based in vivo striatal measures accurately reflect in vitro measures of DAT and VMAT2. Terminal arbor size and other terminal field measures correlate with nigral TH immunoreactive (TH-ir) cell counts only when nigral TH-ir cell loss does not exceed 50%. Fiber length density was the only striatal measure that linearly correlated with motor ratings (Spearman: r=-0.81, p<0.001, n=16).
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Affiliation(s)
- LinLin Tian
- Neurology, Washington University, St. Louis, MO 63110, USA
| | | | - Chris A Brown
- Neurology, Washington University, St. Louis, MO 63110, USA
| | - Susan K Loftin
- Neurology, Washington University, St. Louis, MO 63110, USA
| | - Joel S Perlmutter
- Neurology, Washington University, St. Louis, MO 63110, USA; Radiology, Washington University, St. Louis, MO 63110, USA; Neurobiology, Washington University, St. Louis, MO 63110, USA; Occupational Therapy, Washington University, St. Louis, MO 63110, USA; Physical Therapy, Washington University, St. Louis, MO 63110, USA.
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22
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Pijarowska-Kruszyna J, Jaron AW, Kachniarz A, Kasprzak K, Kowalska A, Malkowski B, Demphel S, Dollé F, Mikolajczak R. Synthesis of novel halo and tosyloxy nortropane derivatives as efficient precursors for the one-step synthesis of the dopamine transporter PET ligand [(18)F]FECNT. J Labelled Comp Radiopharm 2014; 57:148-57. [PMID: 24497079 DOI: 10.1002/jlcr.3181] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Revised: 12/10/2013] [Accepted: 12/10/2013] [Indexed: 11/08/2022]
Abstract
The fluorine-18 labeled nortropane derivative 2β-carbomethoxy-3β-(4-chlorophenyl)-8-(2-fluoroethyl)-nortropane (FECNT) is a dopamine transporter (DAT) ligand. Currently, it is considered as reference for positron emission tomography imaging. Herein, the synthesis of novel precursors (N-tosyloxy-, chloro-, and bromo- analogues) for one-step radiosynthesis of [(18)F]FECNT is reported. Using the N-mesyloxy- precursor in a one-step radiosynthesis, the crude [(18)F]FECNT was obtained with the radiolabeling yield of 45 ± 10%, confirming the practical efficiency of this approach in the design of novel precursors for labeling.
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Affiliation(s)
- J Pijarowska-Kruszyna
- Radioisotope Centre POLATOM, National Centre for Nuclear Research, Andrzeja Soltana 7, Otwock, Poland
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23
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Villalba RM, Wichmann T, Smith Y. Neuronal loss in the caudal intralaminar thalamic nuclei in a primate model of Parkinson's disease. Brain Struct Funct 2014; 219:381-94. [PMID: 23508713 PMCID: PMC3864539 DOI: 10.1007/s00429-013-0507-9] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 01/06/2013] [Indexed: 02/07/2023]
Abstract
In light of postmortem human studies showing extensive degeneration of the center median (CM) and parafascicular (Pf) thalamic nuclei in Parkinson's disease patients, the present study assessed the extent of neuronal loss in CM/Pf of non-human primates that were rendered parkinsonian by repeated injections of low doses of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). In order to determine the course of CM/Pf degeneration during the MPTP intoxication, motor-asymptomatic animals with partial striatal dopamine denervation were also used. The Cavalieri's principle for volume estimation and the unbiased stereological cell count method with the optical dissector technique were used to estimate the total number of neurons in the CM/Pf. We found substantial neurons loss in the CM/Pf in both, motor-symptomatic MPTP-treated monkeys in which the striatal dopamine innervation was reduced by more than 80%, and in motor-asymptomatic MPTP-treated animals with 40-50% striatal dopamine loss. In MPTP-treated parkinsonian monkeys, 60 and 62% neurons loss was found in CM and Pf, respectively, while partially dopamine-depleted asymptomatic animals displayed 59 and 52% neurons loss in the CM and Pf, respectively. Thus, our study demonstrates that the CM/Pf neurons loss is an early phenomenon that occurs prior to the development of parkinsonian motor symptoms in these animals. In contrast, the neighboring mediodorsal nucleus of the thalamus was only mildly affected (18% neurons loss) in the parkinsonian monkeys. Together with recent findings about the possible role of the CM/Pf-striatal system in cognition, our findings suggest that the pathology of the thalamostriatal system may precede the development of motor symptoms in PD, and may account for some of the cognitive deficits in attentional set-shifting often seen in these patients. Future studies in this animal model, and in monkeys with selective lesion of CM or Pf, are needed to further elucidate the role of the CM/Pf-striatal system in normal and parkinsonian conditions.
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Affiliation(s)
- R. M. Villalba
- Yerkes National Primate Research Center, Emory University, 954 Gatewood Rd. NE, Atlanta, GA 30329, USA, , Udall Center of Excellence for Parkinson's Disease Research, Emory University, Atlanta, GA, USA
| | - T. Wichmann
- Yerkes National Primate Research Center, Emory University, 954 Gatewood Rd. NE, Atlanta, GA 30329, USA, , Udall Center of Excellence for Parkinson's Disease Research, Emory University, Atlanta, GA, USADepartment of Neurology, Emory University, Atlanta, GA, USA
| | - Y. Smith
- Yerkes National Primate Research Center, Emory University, 954 Gatewood Rd. NE, Atlanta, GA 30329, USA, , Udall Center of Excellence for Parkinson's Disease Research, Emory University, Atlanta, GA, USA, Department of Neurology, Emory University, Atlanta, GA, USA
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24
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In vivo PET quantification of the dopamine transporter in rat brain with [18F]LBT-999. Nucl Med Biol 2014; 41:106-13. [DOI: 10.1016/j.nucmedbio.2013.09.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Revised: 08/22/2013] [Accepted: 09/23/2013] [Indexed: 11/23/2022]
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25
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Nye JA, Votaw JR, Bremner JD, Davis MR, Voll RJ, Camp VM, Goodman MM. Quantification of dopamine transporter density with [18F]FECNT PET in healthy humans. Nucl Med Biol 2013; 41:217-22. [PMID: 24533985 DOI: 10.1016/j.nucmedbio.2013.12.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 12/04/2013] [Accepted: 12/10/2013] [Indexed: 10/25/2022]
Abstract
INTRODUCTION Fluorine-18 labeled 2β-carbomethoxy-3β-(4-chlorophenyl)-8-(2-fluoroethyl)nortropane ([(18)F]FECNT) binds reversibly to the dopamine transporter (DAT) with high selectivity. [(18)F]FECNT has been used extensively in the quantification of DAT occupancy in non-human primate brain and can distinguish between Parkinson's and healthy controls in humans. The purpose of this work was to develop a compartment model to characterize the kinetics of [(18)F]FECNT for quantification of DAT density in healthy human brain. METHODS Twelve healthy volunteers underwent 180 min dynamic [(18)F]FECNT PET imaging including sampling of arterial blood. Regional time-activity curves were extracted from the caudate, putamen and midbrain including a reference region placed in the cerebellum. Binding potential, BPND, was calculated for all regions using kinetic parameters estimated from compartmental and Logan graphical model fits to the time-activity data. Simulations were performed to determine whether the compartment model could reliably fit time-activity data over a range of BPND values. RESULTS The kinetics of [(18)F]FECNT were well-described by the reversible 2-tissue arterial input and full reference tissue compartment models. Calculated binding potentials in the caudate, putamen and midbrain were in good agreement between the arterial input model, reference tissue model and the Logan graphical model. The distribution volume in the cerebellum did not reach a plateau over the duration of the study, which may be a result of non-specific binding in the cerebellum. Simulations that included non-specific binding show that the reference and arterial input models are able to estimate BPND for DAT densities well below that observed in normal volunteers. CONCLUSION The kinetics of [(18)F]FECNT in human brain are well-described by arterial input and reference tissue compartment models. Measured and simulated data show that BPND calculated with reference tissue model is proportional to BPND calculated from the arterial input model.
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Affiliation(s)
- Jonathon A Nye
- Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA 30329.
| | - John R Votaw
- Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA 30329; Department of Psychiatry and Behavioral Sciences, Emory University, Atlanta, GA 30322
| | - J Douglas Bremner
- Department of Psychiatry and Behavioral Sciences, Emory University, Atlanta, GA 30322
| | - Margaret R Davis
- Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA 30329
| | - Ronald J Voll
- Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA 30329
| | - Vernon M Camp
- Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA 30329
| | - Mark M Goodman
- Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA 30329
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26
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Converse AK, Moore CF, Moirano JM, Ahlers EO, Larson JA, Engle JW, Barnhart TE, Murali D, Christian BT, DeJesus OT, Holden JE, Nickles RJ, Schneider ML. Prenatal stress induces increased striatal dopamine transporter binding in adult nonhuman primates. Biol Psychiatry 2013; 74:502-10. [PMID: 23726316 PMCID: PMC3775901 DOI: 10.1016/j.biopsych.2013.04.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Revised: 04/22/2013] [Accepted: 04/25/2013] [Indexed: 11/15/2022]
Abstract
BACKGROUND To determine the effects in adult offspring of maternal exposure to stress and alcohol during pregnancy, we imaged striatal and midbrain dopamine transporter (DAT) binding by positron emission tomography in rhesus monkeys (Macaca mulatta). We also evaluated the relationship between DAT binding and behavioral responses previously found to relate to dopamine D2 receptor density (responsivity to tactile stimuli, performance on a learning task, and behavior during a learning task). METHODS Subjects were adult offspring derived from a 2 × 2 experiment in which pregnant monkeys were randomly assigned to control, daily mild stress exposure (acoustic startle), voluntary consumption of moderate-level alcohol, or both daily stress and alcohol. Adult offspring (n = 38) were imaged by positron emission tomography with the DAT ligand [(18)F]2β-carbomethoxy-3β-(4-chlorophenyl)-8-(2-fluoroethyl)-nortropane ([(18)F]FECNT). RESULTS Results showed that prenatal stress yielded an overall increase of 15% in [(18)F]FECNT binding in the striatum (p = .016), 17% greater binding in the putamen (p = .012), and 13% greater binding in the head of the caudate (p = .028) relative to animals not exposed to prenatal stress. Striatal [(18)F]FECNT binding correlated negatively with habituation to repeated tactile stimulation and positively with tactile responsivity. There were no significant effects of prenatal alcohol exposure on [(18)F]FECNT binding. CONCLUSIONS Maternal exposure to mild daily stress during pregnancy yielded increases in striatal DAT availability that were apparent in adult offspring and were associated with behavioral characteristics reflecting tactile hyperresponsivity, a condition associated with problem behaviors in children.
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Affiliation(s)
- Alexander K. Converse
- Waisman Center, University of Wisconsin-Madison,Corresponding author: , tel. 001/608/265.6604, T123 Waisman Center, University of Wisconsin-Madison, Madison, WI 53704
| | | | | | | | - Julie A. Larson
- Harlow Center for Biological Psychology, University of Wisconsin-Madison,Department of Kinesiology, University of Wisconsin-Madison
| | | | | | | | | | | | - James E. Holden
- Department of Medical Physics, University of Wisconsin-Madison
| | | | - Mary L. Schneider
- Harlow Center for Biological Psychology, University of Wisconsin-Madison,Department of Psychology, University of Wisconsin-Madison,Department of Kinesiology, University of Wisconsin-Madison
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Brown CA, Karimi MK, Tian L, Flores H, Su Y, Tabbal SD, Loftin SK, Moerlein SM, Perlmutter JS. Validation of midbrain positron emission tomography measures for nigrostriatal neurons in macaques. Ann Neurol 2013; 74:602-10. [PMID: 23686841 PMCID: PMC3800272 DOI: 10.1002/ana.23939] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 04/24/2013] [Accepted: 05/10/2013] [Indexed: 11/10/2022]
Abstract
OBJECTIVE Development of an effective therapy to slow the inexorable progression of Parkinson disease requires a reliable, objective measurement of disease severity. In the present study, we compare presynaptic positron emission tomography (PET) tracer uptake in the substantia nigra (SN) to cell loss and motor impairment in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated nonhuman primates. METHODS Presynaptic PET tracers 6-[(18)F]-fluorodopa (FD), [(11)C]-2β-methoxy-3β-4-fluorophenyltropane (CFT), and [(11)C]-dihydrotetrabenazine (DTBZ) were used to measure specific uptake in the SN and striatum before and after a variable dose of MPTP in nonhuman primates. These in vivo PET-based measures were compared with motor impairment, as well as postmortem tyrosine hydroxylase-positive cell counts and striatal dopamine concentration. RESULTS We found the specific uptake of both CFT and DTBZ in the SN had a strong, significant correlation with dopaminergic cell counts in the SN (R(2) = 0.77, 0.53, respectively, p < 0.001), but uptake of FD did not. Additionally, both CFT and DTBZ specific uptake in the SN had a linear relationship with motor impairment (rs = -0.77, -0.71, respectively, p < 0.001), but FD uptake did not. INTERPRETATION Our findings demonstrate that PET-measured binding potentials for CFT and DTBZ for a midbrain volume of interest targeted at the SN provide faithful correlates of nigral neuronal counts across a full range of lesion severity. Because these measures correlate with both nigral cell counts and parkinsonian ratings, we suggest that these SN PET measures are relevant biomarkers of nigrostriatal function.
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28
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Hargreaves RJ, Rabiner EA. Translational PET imaging research. Neurobiol Dis 2013; 61:32-8. [PMID: 24055214 DOI: 10.1016/j.nbd.2013.08.017] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 08/07/2013] [Accepted: 08/14/2013] [Indexed: 10/26/2022] Open
Abstract
The goal of any early central nervous system (CNS) drug development program is always to test the mechanism and not the molecule in order to support additional research investments in late phase clinical trials. Confirmation that drugs reach their targets using translational positron emission tomography (PET) imaging markers of engagement is central to successful clinical proof-of-concept testing and has become an important feature of most neuropsychiatric drug development programs. CNS PET imaging can also play an important role in the clinical investigation of the neuropharmacological basis of psychiatric disease and the optimization of drug therapy.
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Affiliation(s)
- Richard J Hargreaves
- Merck and Co, WP-42-212, 770, Sumneytown Pike, PO Box 4, West Point, PA19486, USA.
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Karimi M, Tian L, Brown CA, Flores HP, Loftin SK, Videen TO, Moerlein SM, Perlmutter JS. Validation of nigrostriatal positron emission tomography measures: critical limits. Ann Neurol 2013; 73:390-6. [PMID: 23423933 PMCID: PMC3631302 DOI: 10.1002/ana.23798] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 09/28/2012] [Accepted: 10/29/2012] [Indexed: 01/27/2023]
Abstract
OBJECTIVE Molecular imaging and clinical endpoints are frequently discordant in Parkinson disease clinical trials, raising questions about validity of these imaging measures to reflect disease severity. We compared striatal uptake for 3 positron emission tomography (PET) tracers with in vitro measures of nigral cell counts and striatal dopamine in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated monkeys. METHODS Sixteen macaques had magnetic resonance imaging and baseline PETs using 6-[18F]fluorodopa (FD), [11C]dihydrotetrabenazine (DTBZ), and 2beta-[11 C]carbomethoxy-3beta-(4-fluorophenyl)tropane (CFT). MPTP (0-0.31 mg/kg) infused unilaterally via the internal carotid artery produced stable hemiparkinsonism by 3 weeks. After 8 weeks, PETs were repeated and animals were euthanized for striatal dopamine measurements and unbiased counts of tyrosine hydroxylase-stained nigral cells. RESULTS Striatal uptake for each radiotracer (FD, DTBZ, CFT) correlated with stereologic nigral cell counts only for nigral loss<50% (r2=0.84, r2=0.86, r2=0.87, p<0.001 respectively; n=10). In contrast, striatal uptake correlated with striatal dopamine over the full range of dopamine depletion (r2=0.95, r2=0.94, r2=0.94, p<0.001; n=16). Interestingly, indices of striatal uptake of FD, DTBZ, and CFT correlated strongly with each other (r2=0.98, p<0.001). INTERPRETATION Tracer uptake correlated with nigral neurons only when nigral loss was <50%. This along with previous work demonstrating that nigral cell counts correlate strongly with parkinsonism ratings may explain discordant results between neuroimaging and clinical endpoints. Furthermore, strong correlations among striatal uptake for these tracers support lack of differential regulation of decarboxylase activity (FD), vesicular monoamine transporter type 2 (DTBZ), and dopamine transporter (CFT) within 2 months after nigrostriatal injury.
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Affiliation(s)
| | - LinLin Tian
- Neurology, Washington University, St. Louis, MO, USA
| | | | | | | | - Tom O. Videen
- Neurology, Washington University, St. Louis, MO, USA
- Radiology, Washington University, St. Louis, MO, USA
| | - Stephen M. Moerlein
- Radiology, Washington University, St. Louis, MO, USA
- Biochemistry and Molecular Biophysics, Washington University, St. Louis, MO, USA
| | - Joel S. Perlmutter
- Neurology, Washington University, St. Louis, MO, USA
- Radiology, Washington University, St. Louis, MO, USA
- Neurobiology, Washington University, St. Louis, MO, USA
- Occupational Therapy, Washington University, St. Louis, MO, USA
- Physical Therapy Washington University, St. Louis, MO, USA
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Ando K, Obayashi S, Nagai Y, Oh-Nishi A, Minamimoto T, Higuchi M, Inoue T, Itoh T, Suhara T. PET analysis of dopaminergic neurodegeneration in relation to immobility in the MPTP-treated common marmoset, a model for Parkinson's disease. PLoS One 2012; 7:e46371. [PMID: 23056291 PMCID: PMC3466292 DOI: 10.1371/journal.pone.0046371] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Accepted: 08/29/2012] [Indexed: 01/12/2023] Open
Abstract
Background Positron Emission Tomography (PET) measurement was applied to the brain of the common marmoset, a small primate species, treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). The marmoset shows prominent Parkinson’s disease (PD) signs due to dopaminergic neural degeneration. Recently, the transgenic marmoset (TG) carrying human PD genes is developing. For phenotypic evaluations of TG, non-invasive PET measurement is considered to be substantially significant. As a reference control for TG, the brain of the MPTP-marmoset as an established and valid model was scanned by PET. Behavioral analysis was also performed by recording locomotion of the MPTP-marmoset, as an objective measure of PD signs. Methodology/Principal Findings Marmosets received several MPTP regimens (single MPTP regimen: 2 mg/kg, s.c., per day for 3 consecutive days) were used for PET measurement and behavioral observation. To measure immobility as a central PD sign, locomotion of marmosets in their individual living cages were recorded daily by infrared sensors. Daily locomotion counts decreased drastically after MPTP regimens and remained diminished for several months or more. PET scan of the brain, using [11C]PE2I as a ligand of the dopamine (DA) transporter, was performed once several months after the last MPTP regimen. The mean binding potential (BPND) in the striatum (putamen and caudate) of the MPTP-marmoset group was significantly lower than that of the MPTP-free control group (n = 5 for each group). In the MPTP-marmosets, the decrease of BPND in the striatum closely correlated with the decrease in locomotion counts (r = 0.98 in putamen and 0.91 in caudate). Conclusion/Significance The present characterization of neural degeneration using non-invasive PET imaging and of behavioral manifestation in the MPTP marmoset mimics typical PD characteristics and can be useful in evaluating the phenotype of TG marmosets being developed.
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Affiliation(s)
- Kiyoshi Ando
- Central Institute for Experimental Animals, Kawasakiku, Kawasaki, Kanagawa, Japan.
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Wang J, Hoekstra JG, Zuo C, Cook TJ, Zhang J. Biomarkers of Parkinson's disease: current status and future perspectives. Drug Discov Today 2012; 18:155-62. [PMID: 22982303 DOI: 10.1016/j.drudis.2012.09.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Revised: 08/14/2012] [Accepted: 09/05/2012] [Indexed: 01/09/2023]
Abstract
This review summarizes major advances in biomarker discovery for diagnosis, differential diagnosis and progression of Parkinson's disease (PD), with emphasis on neuroimaging and biochemical markers. Potential strategies to develop biomarkers capable of predicting PD in the prodromal stage before the appearance of motor symptoms or correlating with nonmotor symptoms, an active area of research, are also discussed.
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Affiliation(s)
- Jian Wang
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China
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α-1 Adrenergic receptors are localized on presynaptic elements in the nucleus accumbens and regulate mesolimbic dopamine transmission. Neuropsychopharmacology 2012; 37:2161-72. [PMID: 22588352 PMCID: PMC3398716 DOI: 10.1038/npp.2012.68] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Brainstem noradrenergic neurons innervate the mesocorticolimbic reward pathway both directly and indirectly, with norepinephrine facilitating dopamine (DA) neurotransmission via α1-adrenergic receptors (α1ARs). Although α1AR signaling in the prefrontal cortex (PFC) promotes mesolimbic transmission and drug-induced behaviors, the potential contribution of α1ARs in other parts of the pathway, such as the ventral tegmental area (VTA) and nucleus accumbens (NAc), has not been investigated before. We found that local blockade of α1ARs in the medial NAc shell, but not the VTA, attenuates cocaine- and morphine-induced locomotion. To determine the neuronal substrates that could mediate these effects, we analyzed the cellular, subcellular, and subsynaptic localization of α1ARs and characterized the chemical phenotypes of α1AR-containing elements within the mesocorticolimbic system using single and double immunocytochemical methods at the electron microscopic (EM) level. We found that α1ARs are found mainly extra-synaptically in axons and axon terminals in the NAc and are enriched in glutamatergic and dopaminergic elements. α1ARs are also abundant in glutamatergic terminals in the PFC, and in GABA-positive terminals in the VTA. In line with these observations, microdialysis experiments revealed that local blockade of α1ARs attenuated the increase in extracellular DA in the medial NAc shell following administration of cocaine. These data indicate that local α1ARs control DA transmission in the medial NAc shell and behavioral responses to drugs of abuse.
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Virdee K, Cumming P, Caprioli D, Jupp B, Rominger A, Aigbirhio FI, Fryer TD, Riss PJ, Dalley JW. Applications of positron emission tomography in animal models of neurological and neuropsychiatric disorders. Neurosci Biobehav Rev 2012; 36:1188-216. [PMID: 22342372 DOI: 10.1016/j.neubiorev.2012.01.009] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Revised: 01/26/2012] [Accepted: 01/31/2012] [Indexed: 01/08/2023]
Abstract
Positron emission tomography (PET) provides dynamic images of the biodistribution of radioactive tracers in the brain. Through application of the principles of compartmental analysis, tracer uptake can be quantified in terms of specific physiological processes such as cerebral blood flow, cerebral metabolic rate, and the availability of receptors in brain. Whereas early PET studies in animal models of brain diseases were hampered by the limited spatial resolution of PET instruments, dedicated small-animal instruments now provide molecular images of rodent brain with resolution approaching 1mm, the theoretic limit of the method. Major applications of PET for brain research have consisted of studies of animal models of neurological disorders, notably Parkinson's disease (PD), Alzheimer's disease (AD), and Huntington's disease (HD), stroke, epilepsy and traumatic brain injury; these studies have particularly benefited from selective neurochemical lesion models (PD), and also transgenic rodent models (AD, HD). Due to their complex and uncertain pathophysiologies, corresponding models of neuropsychiatric disorders have proven more difficult to establish. Historically, there has been an emphasis on PET studies of dopamine transmission, as assessed with a range of tracers targeting dopamine synthesis, plasma membrane transporters, and receptor binding sites. However, notable recent breakthroughs in molecular imaging include the development of greatly improved tracers for subtypes of serotonin, cannabinoid, and metabotropic glutamate receptors, as well as noradrenaline transporters, amyloid-β and neuroinflammatory changes. This article reviews the considerable recent progress in preclinical PET and discusses applications relevant to a number of neurological and neuropsychiatric disorders in humans.
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Affiliation(s)
- Kanwar Virdee
- Behavioural and Clinical Neuroscience Institute, University of Cambridge, Cambridge, CB2 3EB, UK
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Hadipour-Niktarash A, Rommelfanger KS, Masilamoni GJ, Smith Y, Wichmann T. Extrastriatal D2-like receptors modulate basal ganglia pathways in normal and Parkinsonian monkeys. J Neurophysiol 2011; 107:1500-12. [PMID: 22131382 DOI: 10.1152/jn.00348.2011] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
According to traditional models of the basal ganglia-thalamocortical network of connections, dopamine exerts D2-like receptor (D2LR)-mediated effects through actions on striatal neurons that give rise to the "indirect" pathway, secondarily affecting the activity in the internal and external pallidal segments (GPi and GPe, respectively) and the substantia nigra pars reticulata (SNr). However, accumulating evidence from the rodent literature suggests that D2LR activation also directly influences synaptic transmission in these nuclei. To further examine this issue in primates, we combined in vivo electrophysiological recordings and local intracerebral microinjections of drugs with electron microscopic immunocytochemistry to study D2LR-mediated modulation of neuronal activities in GPe, GPi, and SNr of normal and MPTP-treated (parkinsonian) monkeys. D2LR activation with quinpirole increased firing in most GPe neurons, likely due to a reduction of striatopallidal GABAergic inputs. In contrast, local application of quinpirole reduced firing in GPi and SNr, possibly through D2LR-mediated effects on glutamatergic inputs. Injections of the D2LR antagonist sulpiride resulted in effects opposite to those of quinpirole in GPe and GPi. D2 receptor immunoreactivity was most prevalent in putative striatal-like GABAergic terminals and unmyelinated axons in GPe, GPi, and SNr, but a significant proportion of immunoreactive boutons also displayed ultrastructural features of glutamatergic terminals. Postsynaptic labeling was minimal in all nuclei. The D2LR-mediated effects and pattern of distribution of D2 receptor immunoreactivity were maintained in the parkinsonian state. Thus, in addition to their preferential effects on indirect pathway striatal neurons, extrastriatal D2LR activation in GPi and SNr also influences direct pathway elements in the primate basal ganglia under normal and parkinsonian conditions.
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Pavese N. Do we still need to develop new imaging biomarkers of dopamine denervation for Parkinson's disease? Exp Neurol 2011; 233:118-20. [PMID: 22036688 DOI: 10.1016/j.expneurol.2011.10.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Accepted: 10/11/2011] [Indexed: 11/16/2022]
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Masilamoni GJ, Bogenpohl JW, Alagille D, Delevich K, Tamagnan G, Votaw JR, Wichmann T, Smith Y. Metabotropic glutamate receptor 5 antagonist protects dopaminergic and noradrenergic neurons from degeneration in MPTP-treated monkeys. Brain 2011; 134:2057-73. [PMID: 21705423 PMCID: PMC3122374 DOI: 10.1093/brain/awr137] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Revised: 04/12/2011] [Accepted: 04/24/2011] [Indexed: 12/13/2022] Open
Abstract
Degeneration of the dopaminergic nigrostriatal system and of noradrenergic neurons in the locus coeruleus are important pathological features of Parkinson's disease. There is an urgent need to develop therapies that slow down the progression of neurodegeneration in Parkinson's disease. In the present study, we tested whether the highly specific metabotropic glutamate receptor 5 antagonist, 3-[(2-methyl-1,3-thiazol-4-yl) ethynyl] pyridine, reduces dopaminergic and noradrenergic neuronal loss in monkeys rendered parkinsonian by chronic treatment with low doses of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. Weekly intramuscular 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine injections (0.2-0.5 mg/kg body weight), in combination with daily administration of 3-[(2-methyl-1,3-thiazol-4-yl) ethynyl] pyridine or vehicle, were performed until the development of parkinsonian motor symptoms in either of the two experimental groups (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine/3-[(2-methyl-1,3-thiazol-4-yl) ethynyl] pyridine versus 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine/vehicle). After 21 weeks of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine treatment, all 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine/vehicle-treated animals displayed parkinsonian symptoms, whereas none of the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine/3-[(2-methyl-1,3-thiazol-4-yl) ethynyl] pyridine-treated monkeys were significantly affected. These behavioural observations were consistent with in vivo positron emission tomography dopamine transporter imaging data, and with post-mortem stereological counts of midbrain dopaminergic neurons, as well as striatal intensity measurements of dopamine transporter and tyrosine hydroxylase immunoreactivity, which were all significantly higher in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine/3-[(2-methyl-1,3-thiazol-4-yl) ethynyl] pyridine-treated animals than in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine/vehicle-treated monkeys. The 3-[(2-methyl-1,3-thiazol-4-yl) ethynyl] pyridine treatment also had a significant effect on the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced loss of norepinephrine neurons in the locus coeruleus and adjoining A5 and A7 noradrenaline cell groups. In 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine/vehicle-treated animals, almost 40% loss of tyrosine hydroxylase-positive norepinephrine neurons was found in locus coeruleus/A5/A7 noradrenaline cell groups, whereas the extent of neuronal loss was lower than 15% of control values in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine/3-[(2-methyl-1,3-thiazol-4-yl) ethynyl] pyridine-treated monkeys. Our data demonstrate that chronic treatment with the metabotropic glutamate receptor 5 antagonist, 3-[(2-methyl-1,3-thiazol-4-yl) ethynyl] pyridine, significantly reduces 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine toxicity towards dopaminergic and noradrenergic cell groups in non-human primates. This suggests that the use of metabotropic glutamate receptor 5 antagonists may be a useful strategy to reduce degeneration of catecholaminergic neurons in Parkinson's disease.
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Affiliation(s)
- Gunasingh J Masilamoni
- Yerkes National Primate Research Center, Emory University, 954 Gatewood Rd NE, Atlanta, GA 30329, USA.
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PET molecular imaging in stem cell therapy for neurological diseases. Eur J Nucl Med Mol Imaging 2011; 38:1926-38. [DOI: 10.1007/s00259-011-1860-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Accepted: 06/06/2011] [Indexed: 01/12/2023]
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