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Holden H, Venkatesh S, Budrow C, Nezaria S, Coyle M, Centner A, Lipari N, McManus G, Bishop C. The effects of L-DOPA on gait abnormalities in a unilateral 6-OHDA rat model of Parkinson's disease. Physiol Behav 2024; 281:114563. [PMID: 38723388 DOI: 10.1016/j.physbeh.2024.114563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 04/04/2024] [Accepted: 04/19/2024] [Indexed: 05/27/2024]
Abstract
Parkinson's Disease (PD) is a neurodegenerative movement disorder characterized by dopamine (DA) cell loss in the substantia nigra pars compacta (SNc). As PD progresses, patients display disruptions in gait such as changes in posture, bradykinesia, and shortened stride. DA replacement via L-DOPA alleviates many PD symptoms, though its effects on gait are not well demonstrated. This study aimed to assess the relationship between DA lesion, gait, and deficit-induced reversal with L-DOPA. To do so, Sprague-Dawley rats (N = 25, 14 males, 11 females) received unilateral medial forebrain bundle (MFB) DA lesions with 6-hydroxydopamine (6-OHDA). An automated gait analysis system assessed spatiotemporal gait parameters pre- and post-lesion, and after various doses of L-DOPA (0, 3, or 6 mg/kg; s.c.). The forepaw adjusting steps (FAS) test was implemented to evaluate lesion efficacy while the abnormal involuntary movements (AIMs) scale monitored the emergence of L-DOPA-induced dyskinesia (LID). High performance liquid chromatography (HPLC) assessed changes in brain monoamines on account of lesion and treatment. Results revealed lesion-induced impairments in gait, inclusive of max-contact area and step-sequence alterations that were not reversible with L-DOPA. However, the emergence of AIMs were observed at higher doses. Post-mortem, 6-OHDA lesions induced a loss of striatal DA and norepinephrine (NE), while prefrontal cortex (PFC) displayed noticeable reduction in NE but not DA. Our findings indicate that hemiparkinsonian rats display measurable gait disturbances similar to PD patients that are not rescued by DA replacement. Furthermore, non-DA mechanisms such as attention-related NE in PFC may contribute to altered gait and may constitute a novel target for its treatment.
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Affiliation(s)
- Hannah Holden
- Department of Psychology, Binghamton University, Binghamton, NY, USA
| | - Shruti Venkatesh
- Department of Psychology, Binghamton University, Binghamton, NY, USA
| | - Carla Budrow
- Department of Psychology, Binghamton University, Binghamton, NY, USA
| | - Sareen Nezaria
- Department of Psychology, Binghamton University, Binghamton, NY, USA
| | - Michael Coyle
- Department of Psychology, Binghamton University, Binghamton, NY, USA
| | - Ashley Centner
- Department of Psychology, Binghamton University, Binghamton, NY, USA
| | - Natalie Lipari
- Department of Psychology, Binghamton University, Binghamton, NY, USA
| | - Grace McManus
- Department of Psychology, Binghamton University, Binghamton, NY, USA
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Ryczko D. The Mesencephalic Locomotor Region: Multiple Cell Types, Multiple Behavioral Roles, and Multiple Implications for Disease. Neuroscientist 2024; 30:347-366. [PMID: 36575956 PMCID: PMC11107129 DOI: 10.1177/10738584221139136] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The mesencephalic locomotor region (MLR) controls locomotion in vertebrates. In humans with Parkinson disease, locomotor deficits are increasingly associated with decreased activity in the MLR. This brainstem region, commonly considered to include the cuneiform and pedunculopontine nuclei, has been explored as a target for deep brain stimulation to improve locomotor function, but the results are variable, from modest to promising. However, the MLR is a heterogeneous structure, and identification of the best cell type to target is only beginning. Here, I review the studies that uncovered the role of genetically defined MLR cell types, and I highlight the cells whose activation improves locomotor function in animal models of Parkinson disease. The promising cell types to activate comprise some glutamatergic neurons in the cuneiform and caudal pedunculopontine nuclei, as well as some cholinergic neurons of the pedunculopontine nucleus. Activation of MLR GABAergic neurons should be avoided, since they stop locomotion or evoke bouts flanked with numerous stops. MLR is also considered a potential target in spinal cord injury, supranuclear palsy, primary progressive freezing of gait, or stroke. Better targeting of the MLR cell types should be achieved through optimized deep brain stimulation protocols, pharmacotherapy, or the development of optogenetics for human use.
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Affiliation(s)
- Dimitri Ryczko
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Canada
- Centre de recherche du Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Canada
- Neurosciences Sherbrooke, Sherbrooke, Canada
- Institut de Pharmacologie de Sherbrooke, Sherbrooke, Canada
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Chen RYT, Evans RC. Comparing tonic and phasic dendritic calcium in cholinergic pedunculopontine neurons and dopaminergic substantia nigra neurons. Eur J Neurosci 2024; 59:1638-1656. [PMID: 38383047 PMCID: PMC10987283 DOI: 10.1111/ejn.16281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 01/25/2024] [Accepted: 01/30/2024] [Indexed: 02/23/2024]
Abstract
Several brainstem nuclei degenerate in Parkinson's disease (PD). In addition to the well-characterized dopaminergic neurons of the substantia nigra pars compacta (SNc), the cholinergic neurons of the pedunculopontine nucleus (PPN) also degenerate in PD. One leading hypothesis of selective vulnerability is that pacemaking activity and the activation of low-threshold L-type calcium current are major contributors to tonic calcium load and cellular stress in SNc dopaminergic neurons. However, it is not yet clear whether the vulnerable PPN cholinergic neurons share this property. Therefore, we used two-photon dendritic calcium imaging and whole-cell electrophysiology to evaluate the role of L-type calcium channels in tonic and phasic dendritic calcium signals in PPN and SNc neurons. In addition, we investigated N- and P/Q-type calcium channel regulation of firing properties and dendritic calcium in PPN neurons. We found that blocking L-type channels reduces tonic firing rate and dendritic calcium levels in SNc neurons. By contrast, the tonic calcium load in PPN neurons did not depend on L-, N- or P/Q-type channels. However, we found that blocking either L-type (with nifedipine) or N- and P/Q-type (with omega-conotoxin MVIIC) channels reduces phasic calcium influx in PPN dendrites. Together, these findings show that L-type calcium channels play different roles in the activity of SNc and PPN neurons, and suggest that low-threshold L-type channels are not responsible for tonic calcium levels in PPN cholinergic neurons and are therefore not likely to be a source of selective vulnerability in these cells.
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Affiliation(s)
- Rita Yu-Tzu Chen
- Department of Neuroscience, Georgetown University Medical Center, Washington DC
| | - Rebekah C. Evans
- Department of Neuroscience, Georgetown University Medical Center, Washington DC
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Hu Y, Ma TC, Alberico SL, Ding Y, Jin L, Kang UJ. Substantia Nigra Pars Reticulata Projections to the Pedunculopontine Nucleus Modulate Dyskinesia. Mov Disord 2023; 38:1850-1860. [PMID: 37461292 PMCID: PMC10932617 DOI: 10.1002/mds.29558] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 06/02/2023] [Accepted: 06/29/2023] [Indexed: 07/21/2023] Open
Abstract
BACKGROUND Long-term use of levodopa for Parkinson's disease (PD) treatment is often hindered by development of motor complications, including levodopa-induced dyskinesia (LID). The substantia nigra pars reticulata (SNr) and globus pallidus internal segment (GPi) are the output nuclei of the basal ganglia. Dysregulation of SNr and GPi activity contributes to PD pathophysiology and LID. OBJECTIVE The objective of this study was to determine whether direct modulation of SNr GABAergic neurons and SNr projections to the pedunculopontine nucleus (PPN) regulates PD symptoms and LID in a mouse model. METHODS We expressed Cre-recombinase activated channelrhodopsin-2 (ChR2) or halorhodopsin adeno-associated virus-2 (AAV2) vectors selectively in SNr GABAergic neurons of Vgat-IRES-Cre mice in a 6-hydroxydopamine model of PD to investigate whether direct optogenetic modulation of SNr neurons or their projections to the PPN regulates PD symptoms and LID expression. The forepaw stepping task, mouse LID rating scale, and open-field locomotion were used to assess akinesia and LID to test the effect of SNr modulation. RESULTS Akinesia was improved by suppressing SNr neuron activity with halorhodopsin. LID was significantly reduced by increasing SNr neuronal activity with ChR2, which did not interfere with the antiakinetic effect of levodopa. Optical stimulation of ChR2 in SNr projections to the PPN recapitulated direct SNr stimulation. CONCLUSIONS Modulation of SNr GABAergic neurons alters akinesia and LID expression in a manner consistent with the rate model of basal ganglia circuitry. Moreover, the projections from SNr to PPN likely mediate the antidyskinetic effect of increasing SNr neuronal activity, identifying a potential novel role for the PPN in LID. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Yong Hu
- Department of Neurology, NYU Langone Health, New York, NY 10016, USA
| | - Thong C. Ma
- Department of Neurology, NYU Langone Health, New York, NY 10016, USA
| | | | - Yunmin Ding
- Department of Neurology, NYU Langone Health, New York, NY 10016, USA
| | - Lingjing Jin
- Department of Neurology and Neurological Rehabilitation, Shanghai Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Medicine, Tongji University, Shanghai 200092, China
| | - Un Jung Kang
- Department of Neurology, NYU Langone Health, New York, NY 10016, USA
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Chen RYT, Evans RC. Comparing tonic and phasic calcium in the dendrites of vulnerable midbrain neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.28.555184. [PMID: 37693427 PMCID: PMC10491175 DOI: 10.1101/2023.08.28.555184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Several midbrain nuclei degenerate in Parkinson's Disease (PD). Many of these nuclei share the common characteristics that are thought to contribute to their selective vulnerability, including pacemaking activity and high levels of calcium influx. In addition to the well-characterized dopaminergic neurons of the substantia nigra pars compacta (SNc), the cholinergic neurons of the pedunculopontine nucleus (PPN) also degenerate in PD. It is well established that the low-threshold L-type calcium current is a main contributor to tonic calcium in SNc dopaminergic neurons and is hypothesized to contribute to their selective vulnerability. However, it is not yet clear whether the vulnerable PPN cholinergic neurons share this property. Therefore, we used two-photon dendritic calcium imaging and whole-cell electrophysiology to evaluate the role of L-type calcium channels in the tonic and phasic activity of PPN neurons and the corresponding dendritic calcium signal and directly compare these characteristics to SNc neurons. We found that blocking L-type channels reduces tonic firing rate and dendritic calcium levels in SNc neurons. By contrast, the calcium load in PPN neurons during pacemaking did not depend on L-type channels. However, we find that blocking L-type channels reduces phasic calcium influx in PPN dendrites. Together, these findings show that L-type calcium channels play different roles in the activity of SNc and PPN neurons, and suggest that low-threshold L-type channels are not responsible for tonic calcium levels in PPN cholinergic neurons and are therefore not likely to be a source of selective vulnerability in these cells.
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Affiliation(s)
- Rita Yu-Tzu Chen
- Department of Neuroscience, Georgetown University Medical Center, Washington DC
| | - Rebekah C. Evans
- Department of Neuroscience, Georgetown University Medical Center, Washington DC
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Joza S, Camicioli R, Martin WRW, Wieler M, Gee M, Ba F. Pedunculopontine Nucleus Dysconnectivity Correlates With Gait Impairment in Parkinson’s Disease: An Exploratory Study. Front Aging Neurosci 2022; 14:874692. [PMID: 35875799 PMCID: PMC9304714 DOI: 10.3389/fnagi.2022.874692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Accepted: 06/20/2022] [Indexed: 11/25/2022] Open
Abstract
Background Gait impairment is a debilitating and progressive feature of Parkinson’s disease (PD). Increasing evidence suggests that gait control is partly mediated by cholinergic signaling from the pedunculopontine nucleus (PPN). Objective We investigated whether PPN structural connectivity correlated with quantitative gait measures in PD. Methods Twenty PD patients and 15 controls underwent diffusion tensor imaging to quantify structural connectivity of the PPN. Whole brain analysis using tract-based spatial statistics and probabilistic tractography were performed using the PPN as a seed region of interest for cortical and subcortical target structures. Gait metrics were recorded in subjects’ medication ON and OFF states, and were used to determine if specific features of gait dysfunction in PD were related to PPN structural connectivity. Results Tract-based spatial statistics revealed reduced structural connectivity involving the corpus callosum and right superior corona radiata, but did not correlate with gait measures. Abnormalities in PPN structural connectivity in PD were lateralized to the right hemisphere, with pathways involving the right caudate nucleus, amygdala, pre-supplementary motor area, and primary somatosensory cortex. Altered connectivity of the right PPN-caudate nucleus was associated with worsened cadence, stride time, and velocity while in the ON state; altered connectivity of the right PPN-amygdala was associated with reduced stride length in the OFF state. Conclusion Our exploratory analysis detects a potential correlation between gait dysfunction in PD and a characteristic pattern of connectivity deficits in the PPN network involving the right caudate nucleus and amygdala, which may be investigated in future larger studies.
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Affiliation(s)
- Stephen Joza
- Division of Neurology, Department of Medicine, University of Alberta, Edmonton, AB, Canada
| | - Richard Camicioli
- Division of Neurology, Department of Medicine, University of Alberta, Edmonton, AB, Canada
| | | | - Marguerite Wieler
- Department of Physical Therapy, Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB, Canada
| | - Myrlene Gee
- Division of Neurology, Department of Medicine, University of Alberta, Edmonton, AB, Canada
| | - Fang Ba
- Division of Neurology, Department of Medicine, University of Alberta, Edmonton, AB, Canada
- *Correspondence: Fang Ba,
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Wenger N, Vogt A, Skrobot M, Garulli EL, Kabaoglu B, Salchow-Hömmen C, Schauer T, Kroneberg D, Schuhmann M, Ip CW, Harms C, Endres M, Isaias I, Tovote P, Blum R. Rodent models for gait network disorders in Parkinson's disease - a translational perspective. Exp Neurol 2022; 352:114011. [PMID: 35176273 DOI: 10.1016/j.expneurol.2022.114011] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 01/23/2022] [Accepted: 02/10/2022] [Indexed: 11/26/2022]
Abstract
Gait impairments in Parkinson's disease remain a scientific and therapeutic challenge. The advent of new deep brain stimulation (DBS) devices capable of recording brain activity from chronically implanted electrodes has fostered new studies of gait in freely moving patients. The hope is to identify gait-related neural biomarkers and improve therapy using closed-loop DBS. In this context, animal models offer the opportunity to investigate gait network activity at multiple biological scales and address unresolved questions from clinical research. Yet, the contribution of rodent models to the development of future neuromodulation therapies will rely on translational validity. In this review, we summarize the most effective strategies to model parkinsonian gait in rodents. We discuss how clinical observations have inspired targeted brain lesions in animal models, and whether resulting motor deficits and network oscillations match recent findings in humans. Gait impairments with hypo-, bradykinesia and altered limb rhythmicity were successfully modelled in rodents. However, clear evidence for the presence of freezing of gait was missing. The identification of reliable neural biomarkers for gait impairments has remained challenging in both animals and humans. Moving forward, we expect that the ongoing investigation of circuit specific neuromodulation strategies in animal models will lead to future optimizations of gait therapy in Parkinson's disease.
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Affiliation(s)
- Nikolaus Wenger
- Department of Neurology with experimental Neurology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Charitéplatz 1, 10117 Berlin, Germany; Berlin Institute of Health, Germany.
| | - Arend Vogt
- Department of Neurology with experimental Neurology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Matej Skrobot
- Department of Neurology with experimental Neurology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Elisa L Garulli
- Department of Neurology with experimental Neurology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Burce Kabaoglu
- Department of Neurology with experimental Neurology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Christina Salchow-Hömmen
- Department of Neurology with experimental Neurology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Thomas Schauer
- Technische Universität Berlin, Control Systems Group, 10587 Berlin, Germany
| | - Daniel Kroneberg
- Department of Neurology with experimental Neurology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Charitéplatz 1, 10117 Berlin, Germany; Berlin Institute of Health, Germany
| | - Michael Schuhmann
- Department of Neurology, University Hospital of Würzburg, Josef-Schneider-Straße 11, 97080 Wuerzburg, Germany
| | - Chi Wang Ip
- Department of Neurology, University Hospital of Würzburg, Josef-Schneider-Straße 11, 97080 Wuerzburg, Germany
| | - Christoph Harms
- Department of Neurology with experimental Neurology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Charitéplatz 1, 10117 Berlin, Germany; Center for Stroke Research Berlin, Charité-Universitätsmedizin Berlin, Germany
| | - Matthias Endres
- Department of Neurology with experimental Neurology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt Universität zu Berlin, Charitéplatz 1, 10117 Berlin, Germany; Center for Stroke Research Berlin, Charité-Universitätsmedizin Berlin, Germany; DZHK (German Center for Cardiovascular Research), Berlin Site, Germany; DZNE (German Center for Neurodegenerative Disease), Berlin Site, Germany
| | - Ioannis Isaias
- Department of Neurology, University Hospital of Würzburg, Josef-Schneider-Straße 11, 97080 Wuerzburg, Germany
| | - Philip Tovote
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, Versbacher Str. 5, 97078 Wuerzburg, Germany; Center for Mental Health, University of Wuerzburg, Margarete-Höppel-Platz 1, 97080 Wuerzburg, Germany
| | - Robert Blum
- Department of Neurology, University Hospital of Würzburg, Josef-Schneider-Straße 11, 97080 Wuerzburg, Germany
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Scarduzio M, Hess EJ, Standaert DG, Eskow Jaunarajs KL. Striatal synaptic dysfunction in dystonia and levodopa-induced dyskinesia. Neurobiol Dis 2022; 166:105650. [DOI: 10.1016/j.nbd.2022.105650] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 01/22/2022] [Accepted: 01/24/2022] [Indexed: 12/16/2022] Open
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