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Rossi R, Bærentzen SL, Thomsen MB, Real CC, Wegener G, Grassi-Oliveira R, Gjedde A, Landau AM. A single dose of cocaine raises SV2A density in hippocampus of adolescent rats. Acta Neuropsychiatr 2024; 36:109-117. [PMID: 36847240 DOI: 10.1017/neu.2023.14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
OBJECTIVE Cocaine is a highly addictive psychostimulant that affects synaptic activity with structural and functional adaptations of neurons. The transmembrane synaptic vesicle glycoprotein 2A (SV2A) of pre-synaptic vesicles is commonly used to measure synaptic density, as a novel approach to the detection of synaptic changes. We do not know if a single dose of cocaine suffices to affect pre-synaptic SV2A density, especially during adolescence when synapses undergo intense maturation. Here, we explored potential changes of pre-synaptic SV2A density in target brain areas associated with the cocaine-induced boost of dopaminergic neurotransmission, specifically testing if the effects would last after the return of dopamine levels to baseline. METHODS We administered cocaine (20 mg/kg i.p.) or saline to rats in early adolescence, tested their activity levels and removed the brains 1 hour and 7 days after injection. To evaluate immediate and lasting effects, we did autoradiography with [3H]UCB-J, a specific tracer for SV2A, in medial prefrontal cortex, striatum, nucleus accumbens, amygdala, and dorsal and ventral areas of hippocampus. We also measured the striatal binding of [3H]GBR-12935 to test cocaine's occupancy of the dopamine transporter at both times of study. RESULTS We found a significant increase of [3H]UCB-J binding in the dorsal and ventral sections of hippocampus 7 days after the cocaine administration compared to saline-injected rats, but no differences 1 hour after the injection. The [3H]GBR-12935 binding remained unchanged at both times. CONCLUSION Cocaine provoked lasting changes of hippocampal synaptic SV2A density after a single exposure during adolescence.
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Affiliation(s)
- Rachele Rossi
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Denmark
- Department of Nuclear Medicine and PET Center, Aarhus University Hospital, Aarhus, Denmark
| | - Simone Larsen Bærentzen
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Denmark
- Department of Nuclear Medicine and PET Center, Aarhus University Hospital, Aarhus, Denmark
| | - Majken B Thomsen
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Denmark
- Department of Nuclear Medicine and PET Center, Aarhus University Hospital, Aarhus, Denmark
| | - Caroline C Real
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Denmark
- Department of Nuclear Medicine and PET Center, Aarhus University Hospital, Aarhus, Denmark
| | - Gregers Wegener
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Denmark
| | - Rodrigo Grassi-Oliveira
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Denmark
| | - Albert Gjedde
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Denmark
- Department of Neuroscience, University of Copenhagen, Denmark
- Department of Neurology and Neurosurgery, McGill University, Montreal, Canada
| | - Anne M Landau
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Denmark
- Department of Nuclear Medicine and PET Center, Aarhus University Hospital, Aarhus, Denmark
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Rossi R, Arjmand S, Bærentzen SL, Gjedde A, Landau AM. Synaptic Vesicle Glycoprotein 2A: Features and Functions. Front Neurosci 2022; 16:864514. [PMID: 35573314 PMCID: PMC9096842 DOI: 10.3389/fnins.2022.864514] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 04/05/2022] [Indexed: 01/05/2023] Open
Abstract
In recent years, the field of neuroimaging dramatically moved forward by means of the expeditious development of specific radioligands of novel targets. Among these targets, the synaptic vesicle glycoprotein 2A (SV2A) is a transmembrane protein of synaptic vesicles, present in all synaptic terminals, irrespective of neurotransmitter content. It is involved in key functions of neurons, focused on the regulation of neurotransmitter release. The ubiquitous expression in gray matter regions of the brain is the basis of its candidacy as a marker of synaptic density. Following the development of molecules derived from the structure of the anti-epileptic drug levetiracetam, which selectively binds to SV2A, several radiolabeled markers have been synthetized to allow the study of SV2A distribution with positron emission tomography (PET). These radioligands permit the evaluation of in vivo changes of SV2A distribution held to be a potential measure of synaptic density in physiological and pathological conditions. The use of SV2A as a biomarker of synaptic density raises important questions. Despite numerous studies over the last decades, the biological function and the expressional properties of SV2A remain poorly understood. Some functions of SV2A were claimed, but have not been fully elucidated. While the expression of SV2A is ubiquitous, stronger associations between SV2A and Υ amino butyric acid (GABA)-ergic rather than glutamatergic synapses were observed in some brain structures. A further issue is the unclear interaction between SV2A and its tracers, which reflects a need to clarify what really is detected with neuroimaging tools. Here, we summarize the current knowledge of the SV2A protein and we discuss uncertain aspects of SV2A biology and physiology. As SV2A expression is ubiquitous, but likely more strongly related to a certain type of neurotransmission in particular circumstances, a more extensive knowledge of the protein would greatly facilitate the analysis and interpretation of neuroimaging results by allowing the evaluation not only of an increase or decrease of the protein level, but also of the type of neurotransmission involved.
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Affiliation(s)
- Rachele Rossi
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Nuclear Medicine and PET Center, Aarhus University Hospital, Aarhus, Denmark
| | - Shokouh Arjmand
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Simone Larsen Bærentzen
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Nuclear Medicine and PET Center, Aarhus University Hospital, Aarhus, Denmark
| | - Albert Gjedde
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark.,Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
| | - Anne M Landau
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Nuclear Medicine and PET Center, Aarhus University Hospital, Aarhus, Denmark
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Nielsen SV, Dollerup MR, Bærentzen SL, Landau AM, Munk OL, Alstrup AKO. Validation and optimisation of an automatic blood sampler for preclinical positron emission tomography research in domestic pigs. Lab Anim 2021; 56:287-291. [PMID: 34596450 DOI: 10.1177/00236772211049081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
In preclinical positron emission tomography animal studies, continuous blood sampling is used to measure the time course of the activity concentration in arterial blood. However, pigs have hypercoagulable blood that tends to clot inside plastic tubes. We tested several tube materials and lengths and the use of three-way connectors. We validated set-ups for automated blood sampling with and without blood recirculation that could run for 90 minutes without problematic clots and without any evidence of emboli formation during necropsy.
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Affiliation(s)
- Sofia Vestergaard Nielsen
- Department of Nuclear Medicine and PET Centre, Department of Clinical Medicine, Aarhus University Hospital and Aarhus University, Denmark
| | - Mie Ringgaard Dollerup
- Department of Nuclear Medicine and PET Centre, Department of Clinical Medicine, Aarhus University Hospital and Aarhus University, Denmark
| | - Simone Larsen Bærentzen
- Department of Nuclear Medicine and PET Centre, Department of Clinical Medicine, Aarhus University Hospital and Aarhus University, Denmark
| | - Anne M Landau
- Department of Nuclear Medicine and PET Centre, Department of Clinical Medicine, Aarhus University Hospital and Aarhus University, Denmark
| | - Ole Lajord Munk
- Department of Nuclear Medicine and PET Centre, Department of Clinical Medicine, Aarhus University Hospital and Aarhus University, Denmark
| | - Aage Kristian Olsen Alstrup
- Department of Nuclear Medicine and PET Centre, Department of Clinical Medicine, Aarhus University Hospital and Aarhus University, Denmark
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Binda KH, Lillethorup TP, Real CC, Bærentzen SL, Nielsen MN, Orlowski D, Brooks DJ, Chacur M, Landau AM. Exercise protects synaptic density in a rat model of Parkinson's disease. Exp Neurol 2021; 342:113741. [PMID: 33965411 DOI: 10.1016/j.expneurol.2021.113741] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 05/04/2021] [Indexed: 01/09/2023]
Abstract
BACKGROUND Parkinson's disease (PD) is characterized by Lewy body and neurite pathology associated with dopamine terminal dysfunction. Clinically, it is associated with motor slowing, rigidity, and tremor. Postural instability and pain are also features. Physical exercise benefits PD patients - possibly by promoting neuroplasticity including synaptic regeneration. OBJECTIVES In a parkinsonian rat model, we test the hypotheses that exercise: (a) increases synaptic density and reduces neuroinflammation and (b) lowers the nociceptive threshold by increasing μ-opioid receptor expression. METHODS Brain autoradiography was performed on rats unilaterally injected with either 6-hydroxydopamine (6-OHDA) or saline and subjected to treadmill exercise over 5 weeks. [3H]UCB-J was used to measure synaptic vesicle glycoprotein 2A (SV2A) density. Dopamine D2/3 receptor and μ-opioid receptor availability were assessed with [3H]Raclopride and [3H]DAMGO, respectively, while neuroinflammation was detected with the 18kDA translocator protein (TSPO) marker [3H]PK11195. The nociceptive threshold was determined prior to and throughout the exercise protocol. RESULTS We confirmed a dopaminegic deficit with increased striatal [3H]Raclopride D2/3 receptor availability and reduced nigral tyrosine hydroxylase immunoreactivity in the ipsilateral hemisphere of all 6-OHDA-injected rats. Sedentary rats lesioned with 6-OHDA showed significant reduction of ipsilateral striatal and substantia nigra [3H]UCB-J binding while [3H]PK11195 showed increased ipsilateral striatal neuroinflammation. Lesioned rats who exercised had higher levels of ipsilateral striatal [3H]UCB-J binding and lower levels of neuroinflammation compared to sedentary lesioned rats. Striatal 6-OHDA injections reduced thalamic μ-opioid receptor availability but subsequent exercise restored binding. Exercise also raised thalamic and hippocampal SV2A synaptic density in 6-OHDA lesioned rats, accompanied by a rise in nociceptive threshold. CONCLUSION These data suggest that treadmill exercise protects nigral and striatal synaptic integrity in a rat lesion model of PD - possibly by promoting compensatory mechanisms. Exercise was also associated with reduced neuroinflammation post lesioning and altered opioid transmission resulting in an increased nociceptive threshold.
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Affiliation(s)
- K H Binda
- Translational Neuropsychiatry Unit, Aarhus University, Universitetsbyen 13, Building 2b, Aarhus C 8000, Denmark; Department of Nuclear Medicine and PET, Aarhus University and Hospital, Palle Juul-Jensens Boulevard 165, J109, Aarhus N 8200, Denmark; Laboratory of Functional Neuroanatomy of Pain, Departamento de Anatomia, Universidade de Sao Paulo, Sao Paulo, SP, Brazil.
| | - T P Lillethorup
- Department of Nuclear Medicine and PET, Aarhus University and Hospital, Palle Juul-Jensens Boulevard 165, J109, Aarhus N 8200, Denmark.
| | - C C Real
- Translational Neuropsychiatry Unit, Aarhus University, Universitetsbyen 13, Building 2b, Aarhus C 8000, Denmark; Department of Nuclear Medicine and PET, Aarhus University and Hospital, Palle Juul-Jensens Boulevard 165, J109, Aarhus N 8200, Denmark; Laboratory of Nuclear Medicine (LIM 43), Faculdade de Medicina FMUSP, Universidade de Sao Paulo, Sao Paulo, SP, Brazil.
| | - S L Bærentzen
- Translational Neuropsychiatry Unit, Aarhus University, Universitetsbyen 13, Building 2b, Aarhus C 8000, Denmark; Department of Nuclear Medicine and PET, Aarhus University and Hospital, Palle Juul-Jensens Boulevard 165, J109, Aarhus N 8200, Denmark.
| | - M N Nielsen
- Translational Neuropsychiatry Unit, Aarhus University, Universitetsbyen 13, Building 2b, Aarhus C 8000, Denmark.
| | - D Orlowski
- Center for Experimental Neuroscience (CENSE), Department of Clinical Medicine, Aarhus University and Department of Neurosurgery, Aarhus University Hospital, Aarhus N, 8200, Denmark.
| | - D J Brooks
- Department of Nuclear Medicine and PET, Aarhus University and Hospital, Palle Juul-Jensens Boulevard 165, J109, Aarhus N 8200, Denmark; Institute for Translational and Clinical Research, Newcastle University, Newcastle upon Tyne NE4 5PL, UK.
| | - M Chacur
- Laboratory of Functional Neuroanatomy of Pain, Departamento de Anatomia, Universidade de Sao Paulo, Sao Paulo, SP, Brazil.
| | - A M Landau
- Translational Neuropsychiatry Unit, Aarhus University, Universitetsbyen 13, Building 2b, Aarhus C 8000, Denmark; Department of Nuclear Medicine and PET, Aarhus University and Hospital, Palle Juul-Jensens Boulevard 165, J109, Aarhus N 8200, Denmark.
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Thomsen MB, Schacht AC, Alstrup AKO, Jacobsen J, Lillethorup TP, Bærentzen SL, Noer O, Orlowski D, Elfving B, Müller HK, Brooks DJ, Landau AM. Preclinical PET Studies of [ 11C]UCB-J Binding in Minipig Brain. Mol Imaging Biol 2020; 22:1290-1300. [PMID: 32514885 DOI: 10.1007/s11307-020-01506-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
PURPOSE Loss of neuronal synapse function is associated with a number of brain disorders. The [11C]UCB-J positron emission tomography (PET) tracer allows for in vivo examination of synaptic density, as it binds to synaptic vesicle glycoprotein 2A (SV2A) expressed in presynaptic terminals. Here, we characterise [11C]UCB-J imaging in Göttingen minipigs. PROCEDURES Using PET imaging, we examined tracer specificity and compared kinetic models. We explored the use of a standard blood curve and centrum semiovale white matter as a reference region. We compared in vivo [11C]UCB-J PET imaging to in vitro autoradiography, Western blotting and real-time quantitative polymerase chain reaction. RESULTS The uptake kinetics of [11C]UCB-J could be described using a 1-tissue compartment model and blocking of SV2A availability with levetiracetam showed dose-dependent specific binding. Population-based blood curves resulted in reliable [11C]UCB-J binding estimates, while it was not possible to use centrum semiovale white matter as a non-specific reference region. Brain [11C]UCB-J PET signals correlated well with [3H]UCB-J autoradiography and SV2A protein levels. CONCLUSIONS [11C]UCB-J PET is a valid in vivo marker of synaptic density in the minipig brain, with binding values close to those reported for humans. Minipig models of disease could be valuable for investigating the efficacy of putative neuroprotective agents for preserving synaptic function in future non-invasive, longitudinal studies.
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Affiliation(s)
- Majken Borup Thomsen
- Department of Nuclear Medicine and PET, Department of Clinical Medicine, Aarhus University, Palle Juul-Jensens Boulevard 165, J, 8200, Aarhus N, Denmark
| | - Anna Christina Schacht
- Department of Nuclear Medicine and PET, Department of Clinical Medicine, Aarhus University, Palle Juul-Jensens Boulevard 165, J, 8200, Aarhus N, Denmark
| | - Aage Kristian Olsen Alstrup
- Department of Nuclear Medicine and PET, Department of Clinical Medicine, Aarhus University, Palle Juul-Jensens Boulevard 165, J, 8200, Aarhus N, Denmark
| | - Jan Jacobsen
- Department of Nuclear Medicine and PET, Department of Clinical Medicine, Aarhus University, Palle Juul-Jensens Boulevard 165, J, 8200, Aarhus N, Denmark
| | - Thea Pinholt Lillethorup
- Department of Nuclear Medicine and PET, Department of Clinical Medicine, Aarhus University, Palle Juul-Jensens Boulevard 165, J, 8200, Aarhus N, Denmark
| | - Simone Larsen Bærentzen
- Department of Nuclear Medicine and PET, Department of Clinical Medicine, Aarhus University, Palle Juul-Jensens Boulevard 165, J, 8200, Aarhus N, Denmark.,Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Ove Noer
- Department of Nuclear Medicine and PET, Department of Clinical Medicine, Aarhus University, Palle Juul-Jensens Boulevard 165, J, 8200, Aarhus N, Denmark
| | - Dariusz Orlowski
- Center for Experimental Neuroscience (CENSE), Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Betina Elfving
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Heidi Kaastrup Müller
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - David J Brooks
- Department of Nuclear Medicine and PET, Department of Clinical Medicine, Aarhus University, Palle Juul-Jensens Boulevard 165, J, 8200, Aarhus N, Denmark.,Institute of Translational and Clinical Research, Faculty of Medical Science, Newcastle upon Tyne University, Newcastle upon Tyne, UK
| | - Anne M Landau
- Department of Nuclear Medicine and PET, Department of Clinical Medicine, Aarhus University, Palle Juul-Jensens Boulevard 165, J, 8200, Aarhus N, Denmark. .,Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
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