title: Dopaminergic manipulations and its effects on neurogenesis and motor function in a transgenic mouse model of Huntington's disease.
abstract: Huntington's disease (HD) is an inherited neurodegenerative disorder that is classically defined by a triad of movement and cognitive and psychiatric abnormalities with a well-established pathology that affects the dopaminergic systems of the brain. This has classically been described in terms of an early loss of dopamine D2 receptors (D2R), although interestingly the treatments most effectively used to treat patients with HD block these same receptors. We therefore sought to examine the dopaminergic system in HD not only in terms of striatal function but also at extrastriatal sites especially the hippocampus, given that transgenic (Tg) mice also exhibit deficits in hippocampal-dependent cognitive tests and a reduction in adult hippocampal neurogenesis. We showed that there was an early reduction of D2R in both the striatum and dentate gyrus (DG) of the hippocampus in the R6/1 transgenic HD mouse ahead of any overt motor signs and before striatal neuronal loss. Despite downregulation of D2Rs in these sites, further reduction of the dopaminergic input to these sites by either medial forebrain bundle lesions or receptor blockade using sulpiride was able to improve both deficits in motor performance and adult hippocampal neurogenesis. In contrast, a reduction in dopaminergic innervation of the neurogenic niches resulted in impaired neurogenesis in healthy WT mice. This study therefore provides evidence that D2R blockade improves hippocampal and striatal deficits in HD mice although the underlying mechanism for this is unclear, and suggests that agents working within this network may have greater effects than previously thought.
authors.affiliation: Department of Clinical Neurosciences, John van Geest Centre for Brain Repair, University of Cambridge, Cambridge CB2 0PY, UK.
authors.forename: M L
authors.initials: ML
authors.lastname: Choi
authors.affiliation: Department of Clinical Neurosciences, John van Geest Centre for Brain Repair, University of Cambridge, Cambridge CB2 0PY, UK; School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 0SP, UK.
authors.forename: F
authors.initials: F
authors.lastname: Begeti
authors.affiliation: Neuroscience Research Institute, Gachon University, Incheon 405-760, Republic of Korea.
authors.forename: J H
authors.initials: JH
authors.lastname: Oh
authors.affiliation: Neuroscience Research Institute, Gachon University, Incheon 405-760, Republic of Korea.
authors.forename: S Y
authors.initials: SY
authors.lastname: Lee
authors.affiliation: Department of Clinical Neurosciences, John van Geest Centre for Brain Repair, University of Cambridge, Cambridge CB2 0PY, UK.
authors.forename: G C
authors.initials: GC
authors.lastname: O'Keeffe
authors.affiliation: Department of Clinical Neurosciences, John van Geest Centre for Brain Repair, University of Cambridge, Cambridge CB2 0PY, UK.
authors.forename: C D
authors.initials: CD
authors.lastname: Clelland
authors.affiliation: Department of Clinical Neurosciences, John van Geest Centre for Brain Repair, University of Cambridge, Cambridge CB2 0PY, UK.
authors.forename: P
authors.initials: P
authors.lastname: Tyers
authors.affiliation: Department of Clinical Neurosciences, John van Geest Centre for Brain Repair, University of Cambridge, Cambridge CB2 0PY, UK.
authors.forename: Z H
authors.initials: ZH
authors.lastname: Cho
authors.affiliation: Department of Clinical Neurosciences, John van Geest Centre for Brain Repair, University of Cambridge, Cambridge CB2 0PY, UK.
authors.forename: Y B
authors.initials: YB
authors.lastname: Kim
authors.affiliation: Department of Clinical Neurosciences, John van Geest Centre for Brain Repair, University of Cambridge, Cambridge CB2 0PY, UK; Department of Neurology, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK. Electronic address: rab46@cam.ac.uk.
authors.forename: R A
authors.initials: RA
authors.lastname: Barker
mesh_terms: D000818:Animals; D001921:Brain / Q000000981:diagnostic imaging / Q000187:drug effects / Q000503:physiopathology*; D003342:Corpus Striatum / Q000000981:diagnostic imaging / Q000187:drug effects / Q000503:physiopathology; D018891:Dentate Gyrus / Q000000981:diagnostic imaging / Q000187:drug effects / Q000503:physiopathology; D004298:Dopamine / Q000378:metabolism*; D018492:Dopamine Antagonists / Q000494:pharmacology; D005260:Female; D006624:Hippocampus / Q000000981:diagnostic imaging / Q000187:drug effects / Q000503:physiopathology; D006816:Huntington Disease / Q000188:drug therapy / Q000503:physiopathology*; D008474:Medial Forebrain Bundle / Q000000981:diagnostic imaging / Q000187:drug effects / Q000503:physiopathology; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009043:Motor Activity / Q000187:drug effects; D058953:Neural Stem Cells / Q000187:drug effects / Q000502:physiology; D055495:Neurogenesis / Q000187:drug effects; D016627:Oxidopamine; D011877:Radionuclide Imaging; D017448:Receptors, Dopamine D2 / Q000378:metabolism; D013469:Sulpiride / Q000494:pharmacology
chemical_list: D018492:Dopamine Antagonists; D017448:Receptors, Dopamine D2; D013469:Sulpiride; D016627:Oxidopamine; D004298:Dopamine
keywords: Adult hippocampal neurogenesis; Dopamine; Huntington's disease