101
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Li Q, Ke Y, Chan DCW, Qian ZM, Yung KKL, Ko H, Arbuthnott GW, Yung WH. Therapeutic deep brain stimulation in Parkinsonian rats directly influences motor cortex. Neuron 2013; 76:1030-41. [PMID: 23217750 DOI: 10.1016/j.neuron.2012.09.032] [Citation(s) in RCA: 233] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/17/2012] [Indexed: 11/19/2022]
Abstract
Much recent discussion about the origin of Parkinsonian symptoms has centered around the idea that they arise with the increase of beta frequency waves in the EEG. This activity may be closely related to an oscillation between subthalamic nucleus (STN) and globus pallidus. Since STN is the target of deep brain stimulation, it had been assumed that its action is on the nucleus itself. By means of simultaneous recordings of the firing activities from populations of neurons and the local field potentials in the motor cortex of freely moving Parkinsonian rats, this study casts doubt on this assumption. Instead, we found evidence that the corrective action is upon the cortex, where stochastic antidromic spikes originating from the STN directly modify the firing probability of the corticofugal projection neurons, destroy the dominance of beta rhythm, and thus restore motor control to the subjects, be they patients or rodents.
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Affiliation(s)
- Qian Li
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China
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102
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Patel JC, Rice ME. Classification of H₂O₂as a neuromodulator that regulates striatal dopamine release on a subsecond time scale. ACS Chem Neurosci 2012; 3:991-1001. [PMID: 23259034 DOI: 10.1021/cn300130b] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Accepted: 10/15/2012] [Indexed: 01/18/2023] Open
Abstract
Here we review evidence that the reactive oxygen species, hydrogen peroxide (H(2)O(2)), meets the criteria for classification as a neuromodulator through its effects on striatal dopamine (DA) release. This evidence was obtained using fast-scan cyclic voltammetry to detect evoked DA release in striatal slices, along with whole-cell and fluorescence imaging to monitor cellular activity and H(2)O(2) generation in striatal medium spiny neurons (MSNs). The data show that (1) exogenous H(2)O(2) suppresses DA release in dorsal striatum and nucleus accumbens shell and the same effect is seen with elevation of endogenous H(2)O(2) levels; (2) H(2)O(2) is generated downstream from glutamatergic AMPA receptor activation in MSNs, but not DA axons; (3) generation of modulatory H(2)O(2) is activity dependent; (4) H(2)O(2) generated in MSNs diffuses to DA axons to cause transient DA release suppression by activating ATP-sensitive K(+) (K(ATP)) channels on DA axons; and (5) the amplitude of H(2)O(2)-dependent inhibition of DA release is attenuated by enzymatic degradation of H(2)O(2), but the subsecond time course is determined by H(2)O(2) diffusion rate and/or K(ATP)-channel kinetics. In the dorsal striatum, neuromodulatory H(2)O(2) is an intermediate in the regulation of DA release by the classical neurotransmitters glutamate and GABA, as well as other neuromodulators, including cannabinoids. However, modulatory actions of H(2)O(2) occur in other regions and cell types, as well, consistent with the widespread expression of K(ATP) and other H(2)O(2)-sensitive channels throughout the CNS.
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Affiliation(s)
- Jyoti C. Patel
- Department
of Neurosurgery, ‡Department of Physiology and Neuroscience, New York University School of Medicine, 550 First Avenue,
New York, New York 10016, United States
| | - Margaret E. Rice
- Department
of Neurosurgery, ‡Department of Physiology and Neuroscience, New York University School of Medicine, 550 First Avenue,
New York, New York 10016, United States
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103
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Hilliard AT, Miller JE, Horvath S, White SA. Distinct neurogenomic states in basal ganglia subregions relate differently to singing behavior in songbirds. PLoS Comput Biol 2012; 8:e1002773. [PMID: 23144607 PMCID: PMC3493463 DOI: 10.1371/journal.pcbi.1002773] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 09/07/2012] [Indexed: 01/13/2023] Open
Abstract
Both avian and mammalian basal ganglia are involved in voluntary motor control. In birds, such movements include hopping, perching and flying. Two organizational features that distinguish the songbird basal ganglia are that striatal and pallidal neurons are intermingled, and that neurons dedicated to vocal-motor function are clustered together in a dense cell group known as area X that sits within the surrounding striato-pallidum. This specification allowed us to perform molecular profiling of two striato-pallidal subregions, comparing transcriptional patterns in tissue dedicated to vocal-motor function (area X) to those in tissue that contains similar cell types but supports non-vocal behaviors: the striato-pallidum ventral to area X (VSP), our focus here. Since any behavior is likely underpinned by the coordinated actions of many molecules, we constructed gene co-expression networks from microarray data to study large-scale transcriptional patterns in both subregions. Our goal was to investigate any relationship between VSP network structure and singing and identify gene co-expression groups, or modules, found in the VSP but not area X. We observed mild, but surprising, relationships between VSP modules and song spectral features, and found a group of four VSP modules that were highly specific to the region. These modules were unrelated to singing, but were composed of genes involved in many of the same biological processes as those we previously observed in area X-specific singing-related modules. The VSP-specific modules were also enriched for processes disrupted in Parkinson's and Huntington's Diseases. Our results suggest that the activation/inhibition of a single pathway is not sufficient to functionally specify area X versus the VSP and support the notion that molecular processes are not in and of themselves specialized for behavior. Instead, unique interactions between molecular pathways create functional specificity in particular brain regions during distinct behavioral states. Understanding how gene transcription relates to behavior is challenging. Learned vocal-motor behavior is a complex trait that represents the output of multiple converging genes, pathways, and patterns of neural activity. Here, we applied a systems analytical approach to determine how thousands of genes change their expression levels simultaneously in a region of the vertebrate brain important for vocal-motor function, the basal ganglia, during a specific vocal-motor behavior, singing. We used the zebra finch species of songbird based on similarities between song learning/production and speech, and because they possess a set of brain subregions dedicated to singing. Microarrays were used to measure gene expression levels in one such song-dedicated region and in an adjacent motor area that is not thought to play a role in vocal function. This allowed us to address the question of whether distinct gene co-expression patterns could be found in each area. We found that each area contained unique patterns of transcriptional co-activity, but there were also unexpected overlaps. We conclude that the particular behaviors (singing versus non-vocal behaviors) supported by these subregions depend on the particular sets of interactions between molecular pathways that occur in each subregion.
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Affiliation(s)
- Austin T Hilliard
- Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, CA, USA
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104
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Shen KZ, Johnson SW. Chronic dopamine depletion augments the functional expression of K-ATP channels in the rat subthalamic nucleus. Neurosci Lett 2012; 531:104-8. [PMID: 23127848 DOI: 10.1016/j.neulet.2012.10.030] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 10/04/2012] [Accepted: 10/17/2012] [Indexed: 10/27/2022]
Abstract
Symptoms of Parkinson's disease caused by dopamine depletion are associated with burst firing in the subthalamic nucleus (STN). Moreover, regularization or suppression of STN neuronal activity is thought to improve symptoms of Parkinson's disease. We reported recently that N-methyl-D-aspartate (NMDA) receptor stimulation of rat STN neurons evokes ATP-sensitive K(+) (K-ATP) current via a Ca(2+)- and nitric oxide-dependent mechanism. The present studies were done to determine whether or not K-ATP channel function in STN neurons is altered in a model of chronic dopamine depletion. Brain slices were prepared from rats with unilateral dopamine depletion caused by intracerebral 6-hydroxydopamine (6-OHDA) injections. Whole-cell patch-clamp recordings showed that NMDA evoked more outward current at -70 mV and greater positive slope conductance in STN neurons located ipsilateral to 6-OHDA treatment compared to neurons located contralateral. Moreover, extracellular, loose-patch recordings showed that NMDA increased spontaneous firing rate in STN neurons in slices from normal rats, whereas NMDA produced a tolbutamide-sensitive inhibition of firing rate in STN neurons located ipsilateral to 6-OHDA treatment. These results show that K-ATP channel function in STN neurons is up-regulated by chronic dopamine deficiency. We suggest that K-ATP channel activation in the STN might benefit symptoms of Parkinson's disease.
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Affiliation(s)
- Ke-Zhong Shen
- Department of Neurology, Oregon Health & Science University, Portland, OR 97239, USA
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105
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Aristieta A, Azkona G, Sagarduy A, Miguelez C, Ruiz-Ortega JÁ, Sanchez-Pernaute R, Ugedo L. The role of the subthalamic nucleus in L-DOPA induced dyskinesia in 6-hydroxydopamine lesioned rats. PLoS One 2012; 7:e42652. [PMID: 22880070 PMCID: PMC3412805 DOI: 10.1371/journal.pone.0042652] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Accepted: 07/09/2012] [Indexed: 01/25/2023] Open
Abstract
L-DOPA is the most effective treatment for Parkinson's disease (PD), but prolonged use leads to disabling motor complications including dyskinesia. Strong evidence supports a role of the subthalamic nucleus (STN) in the pathophysiology of PD whereas its role in dyskinesia is a matter of controversy. Here, we investigated the involvement of STN in dyskinesia, using single-unit extracellular recording, behavioural and molecular approaches in hemi-parkinsonian rats rendered dyskinetic by chronic L-DOPA administration. Our results show that chronic L-DOPA treatment does not modify the abnormal STN activity induced by the 6-hydroxydopamine lesion of the nigrostriatal pathway in this model. Likewise, we observed a loss of STN responsiveness to a single L-DOPA dose both in lesioned and sham animals that received daily L-DOPA treatment. We did not find any correlation between the abnormal involuntary movement (AIM) scores and the electrophysiological parameters of STN neurons recorded 24 h or 20–120 min after the last L-DOPA injection, except for the axial subscores. Nonetheless, unilateral chemical ablation of the STN with ibotenic acid resulted in a reduction in global AIM scores and peak-severity of dyskinesia. In addition, STN lesion decreased the anti-dyskinetogenic effect of buspirone in a reciprocal manner. Striatal protein expression was altered in dyskinetic animals with increases in ΔFosB, phosphoDARPP-32, dopamine receptor (DR) D3 and DRD2/DRD1 ratio. The STN lesion attenuated the striatal molecular changes and normalized the DRD2/DRD1 ratio. Taken together, our results show that the STN plays a role, if modest, in the physiopathology of dyskinesias.
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Affiliation(s)
- Asier Aristieta
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of the Basque Country, Leioa, Spain
| | - Garikoitz Azkona
- Laboratory of Stem Cells and Neural Repair, Fundacion Inbiomed, San Sebastian, Spain
| | - Ainhoa Sagarduy
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of the Basque Country, Leioa, Spain
| | - Cristina Miguelez
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of the Basque Country, Leioa, Spain
| | - José Ángel Ruiz-Ortega
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of the Basque Country, Leioa, Spain
| | - Rosario Sanchez-Pernaute
- Laboratory of Stem Cells and Neural Repair, Fundacion Inbiomed, San Sebastian, Spain
- * E-mail: (RSP); (LU)
| | - Luisa Ugedo
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of the Basque Country, Leioa, Spain
- * E-mail: (RSP); (LU)
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106
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Abstract
Parkinson's disease (PD) is the most common age-related motoric neurodegenerative disease initially described in the 1800's by James Parkinson as the 'Shaking Palsy'. Loss of the neurotransmitter dopamine was recognized as underlying the pathophysiology of the motor dysfunction; subsequently discovery of dopamine replacement therapies brought substantial symptomatic benefit to PD patients. However, these therapies do not fully treat the clinical syndrome nor do they alter the natural history of this disorder motivating clinicians and researchers to further investigate the clinical phenotype, pathophysiology/pathobiology and etiology of this devastating disease. Although the exact cause of sporadic PD remains enigmatic studies of familial and rare toxicant forms of this disorder have laid the foundation for genome wide explorations and environmental studies. The combination of methodical clinical evaluation, systematic pathological studies and detailed genetic analyses have revealed that PD is a multifaceted disorder with a wide-range of clinical symptoms and pathology that include regions outside the dopamine system. One common thread in PD is the presence of intracytoplasmic inclusions that contain the protein, α-synuclein. The presence of toxic aggregated forms of α-synuclein (e.g., amyloid structures) are purported to be a harbinger of subsequent pathology. In fact, PD is both a cerebral amyloid disease and the most common synucleinopathy, that is, diseases that display accumulations of α-synuclein. Here we present our current understanding of PD etiology, pathology, clinical symptoms and therapeutic approaches with an emphasis on misfolded α-synuclein.
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Affiliation(s)
- Timothy R. Mhyre
- Department of Neuroscience, Georgetown University Medical Center, NRB EP08, 3970 Reservoir Road NW, 20057, Washington, DC, USA,
| | - James T. Boyd
- University of Vermont College of Medicine, 1 South Prospect Street, DU-Arnold 4416-UHC, 05401, Burlington, VT, USA,
| | - Robert W. Hamill
- Department of Neurology, University of Vermont College of Medicine, 89 Beaumont Avenue, Given Hall Room C225, 05405, Burlington, VT, USA,
| | - Kathleen A. Maguire-Zeiss
- Department of Neuroscience, Center for Neural Injury and RecoveryGeorgetown University Medical Center, 3970 Reservoir Road, NW NRB EP08, 20057, Washington, DC, USA,
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107
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Rice ME, Patel JC, Cragg SJ. Dopamine release in the basal ganglia. Neuroscience 2011; 198:112-37. [PMID: 21939738 PMCID: PMC3357127 DOI: 10.1016/j.neuroscience.2011.08.066] [Citation(s) in RCA: 193] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Revised: 08/22/2011] [Accepted: 08/26/2011] [Indexed: 10/17/2022]
Abstract
Dopamine (DA) is a key transmitter in the basal ganglia, yet DA transmission does not conform to several aspects of the classic synaptic doctrine. Axonal DA release occurs through vesicular exocytosis and is action potential- and Ca²⁺-dependent. However, in addition to axonal release, DA neurons in midbrain exhibit somatodendritic release by an incompletely understood, but apparently exocytotic, mechanism. Even in striatum, axonal release sites are controversial, with evidence for DA varicosities that lack postsynaptic specialization, and largely extrasynaptic DA receptors and transporters. Moreover, DA release is often assumed to reflect a global response to a population of activities in midbrain DA neurons, whether tonic or phasic, with precise timing and specificity of action governed by other basal ganglia circuits. This view has been reinforced by anatomical evidence showing dense axonal DA arbors throughout striatum, and a lattice network formed by DA axons and glutamatergic input from cortex and thalamus. Nonetheless, localized DA transients are seen in vivo using voltammetric methods with high spatial and temporal resolution. Mechanistic studies using similar methods in vitro have revealed local regulation of DA release by other transmitters and modulators, as well as by proteins known to be disrupted in Parkinson's disease and other movement disorders. Notably, the actions of most other striatal transmitters on DA release also do not conform to the synaptic doctrine, with the absence of direct synaptic contacts for glutamate, GABA, and acetylcholine (ACh) on striatal DA axons. Overall, the findings reviewed here indicate that DA signaling in the basal ganglia is sculpted by cooperation between the timing and pattern of DA input and those of local regulatory factors.
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Affiliation(s)
- M E Rice
- Department of Neurosurgery, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA.
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108
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Bevan MD. Introduction to the special edition: function and dysfunction of the basal ganglia. Neuroscience 2011; 198:1-2. [PMID: 21996475 DOI: 10.1016/j.neuroscience.2011.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- M D Bevan
- Department of Physiology, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Avenue, Chicago, IL 60611, USA.
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