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Vaidya B, Padhy DS, Joshi HC, Sharma SS, Singh JN. Ion Channels and Metal Ions in Parkinson's Disease: Historical Perspective to the Current Scenario. Methods Mol Biol 2024; 2761:529-557. [PMID: 38427260 DOI: 10.1007/978-1-0716-3662-6_36] [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] [Indexed: 03/02/2024]
Abstract
Parkinson's disease (PD) is a neurodegenerative condition linked to the deterioration of motor and cognitive performance. It produces degeneration of the dopaminergic neurons along the nigrostriatal pathway in the central nervous system (CNS), which leads to symptoms such as bradykinesias, tremors, rigidity, and postural instability. There are several medications currently approved for the therapy of PD, but a permanent cure for it remains elusive. With the aging population set to increase, a number of PD cases are expected to shoot up in the coming times. Hence, there is a need to look for new molecular targets that could be investigated both preclinically and clinically for PD treatment. Among these, several ion channels and metal ions are being studied for their effects on PD pathology and the functioning of dopaminergic neurons. Ion channels such as N-methyl-D-aspartate (NMDA), γ-aminobutyric acid A (GABAA), voltage-gated calcium channels, potassium channels, HCN channels, Hv1 proton channels, and voltage-gated sodium channels and metal ions such as mercury, zinc, copper, iron, manganese, calcium, and lead showed prominent involvement in PD. Pharmacological agents have been used to target these ion channels and metal ions to prevent or treat PD. Hence, in the present review, we summarize the pathophysiological events linked to PD with an emphasis on the role of ions and ion channels in PD pathology, and pharmacological agents targeting these ion channels have also been listed.
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Affiliation(s)
- Bhupesh Vaidya
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Punjab, India
| | - Dibya S Padhy
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Punjab, India
| | - Hem C Joshi
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Punjab, India
| | - Shyam S Sharma
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Punjab, India.
| | - Jitendra Narain Singh
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Punjab, India.
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2
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Matthews LG, Puryear CB, Correia SS, Srinivasan S, Belfort GM, Pan MK, Kuo SH. T-type calcium channels as therapeutic targets in essential tremor and Parkinson's disease. Ann Clin Transl Neurol 2023; 10:462-483. [PMID: 36738196 PMCID: PMC10109288 DOI: 10.1002/acn3.51735] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 12/20/2022] [Accepted: 12/21/2022] [Indexed: 02/05/2023] Open
Abstract
Neuronal action potential firing patterns are key components of healthy brain function. Importantly, restoring dysregulated neuronal firing patterns has the potential to be a promising strategy in the development of novel therapeutics for disorders of the central nervous system. Here, we review the pathophysiology of essential tremor and Parkinson's disease, the two most common movement disorders, with a focus on mechanisms underlying the genesis of abnormal firing patterns in the implicated neural circuits. Aberrant burst firing of neurons in the cerebello-thalamo-cortical and basal ganglia-thalamo-cortical circuits contribute to the clinical symptoms of essential tremor and Parkinson's disease, respectively, and T-type calcium channels play a key role in regulating this activity in both the disorders. Accordingly, modulating T-type calcium channel activity has received attention as a potentially promising therapeutic approach to normalize abnormal burst firing in these diseases. In this review, we explore the evidence supporting the theory that T-type calcium channel blockers can ameliorate the pathophysiologic mechanisms underlying essential tremor and Parkinson's disease, furthering the case for clinical investigation of these compounds. We conclude with key considerations for future investigational efforts, providing a critical framework for the development of much needed agents capable of targeting the dysfunctional circuitry underlying movement disorders such as essential tremor, Parkinson's disease, and beyond.
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Affiliation(s)
| | - Corey B Puryear
- Praxis Precision Medicines, Boston, Massachusetts, 02110, USA
| | | | - Sharan Srinivasan
- Praxis Precision Medicines, Boston, Massachusetts, 02110, USA.,Department of Neurology, University of Michigan, Ann Arbor, Michigan, 48109, USA
| | | | - Ming-Kai Pan
- Department and Graduate Institute of Pharmacology, National Taiwan University College of Medicine, Taipei, 10051, Taiwan.,Neurobiology and Cognitive Science Center, National Taiwan University, Taipei, 10617, Taiwan.,Department of Medical Research, National Taiwan University Hospital, Taipei, 10002, Taiwan.,Cerebellar Research Center, National Taiwan University Hospital, Yun-Lin Branch, Yun-Lin, 64041, Taiwan
| | - Sheng-Han Kuo
- Department of Neurology, Columbia University, New York, New York, 10032, USA.,Initiative for Columbia Ataxia and Tremor, Columbia University, New York, New York, 10032, USA
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3
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Parr-Brownlie LC, Itoga CA, Walters JR, Underwood CF. Oscillatory waveform sharpness asymmetry changes in motor thalamus and motor cortex in a rat model of Parkinson's disease. Exp Neurol 2022; 354:114089. [PMID: 35461830 PMCID: PMC11345867 DOI: 10.1016/j.expneurol.2022.114089] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 04/01/2022] [Accepted: 04/17/2022] [Indexed: 11/23/2022]
Abstract
Parkinson's disease (PD) causes bursty and oscillatory activity in basal ganglia output that is thought to contribute to movement deficits through impact on motor thalamus and motor cortex (MCx). We examined the effect of dopamine loss on motor thalamus and motor cortex activity by recording neuronal and LFP activities in ventroanterior-ventrolateral (VAVL) thalamus and MCx in urethane-anesthetised control and parkinsonian rats. Dopamine lesion decreased the firing rate and increased the bursting of putative pyramidal neurons in layer V, but not layer VI, of the MCx without changing other aspects of firing pattern. In contrast, dopamine lesion did not affect VAVL firing rate, pattern or low threshold calcium spike bursts. Slow-wave (~1 Hz) oscillations in LFP recordings were analyzed with conventional power and waveform shape analyses. While dopamine lesion did not influence total power, it was consistently associated with an increase in oscillatory waveform sharpness asymmetry (i.e., sharper troughs vs. peaks) in both motor thalamus and MCx. Furthermore, we found that measures of sharpness asymmetry were positively correlated in paired motor thalamus-MCx recordings, and that correlation coefficients were larger in dopamine lesioned rats. These data support the idea that dysfunctional MCx activity in parkinsonism emerges from subsets of cell groups (e.g. layer V pyramidal neurons) and is evident in the shape but not absolute power of slow-wave oscillations. Hypoactive layer V pyramidal neuron firing in dopamine lesioned rats is unlikely to be driven by VAVL thalamus and may, therefore, reflect the loss of mesocortical dopaminergic afferents and/or changes in intrinsic excitability.
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Affiliation(s)
- Louise C Parr-Brownlie
- Department of Anatomy, Brain Health Research Centre, Brain Research New Zealand, University of Otago, Dunedin, New Zealand; Neurophysiological Pharmacology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, 35 Convent Drive, Building 35 Room 1C 903, Bethesda, MD 20892-3702, USA.
| | - Christy A Itoga
- Neurophysiological Pharmacology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, 35 Convent Drive, Building 35 Room 1C 903, Bethesda, MD 20892-3702, USA
| | - Judith R Walters
- Neurophysiological Pharmacology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, 35 Convent Drive, Building 35 Room 1C 903, Bethesda, MD 20892-3702, USA
| | - Conor F Underwood
- Department of Anatomy, Brain Health Research Centre, Brain Research New Zealand, University of Otago, Dunedin, New Zealand
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4
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Nakamura KC, Sharott A, Tanaka T, Magill PJ. Input Zone-Selective Dysrhythmia in Motor Thalamus after Dopamine Depletion. J Neurosci 2021; 41:10382-10404. [PMID: 34753740 PMCID: PMC8672689 DOI: 10.1523/jneurosci.1753-21.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 09/19/2021] [Accepted: 09/23/2021] [Indexed: 12/01/2022] Open
Abstract
The cerebral cortex, basal ganglia and motor thalamus form circuits important for purposeful movement. In Parkinsonism, basal ganglia neurons often exhibit dysrhythmic activity during, and with respect to, the slow (∼1 Hz) and beta-band (15-30 Hz) oscillations that emerge in cortex in a brain state-dependent manner. There remains, however, a pressing need to elucidate the extent to which motor thalamus activity becomes similarly dysrhythmic after dopamine depletion relevant to Parkinsonism. To address this, we recorded single-neuron and ensemble outputs in the basal ganglia-recipient zone (BZ) and cerebellar-recipient zone (CZ) of motor thalamus in anesthetized male dopamine-intact rats and 6-OHDA-lesioned rats during two brain states, respectively defined by cortical slow-wave activity and activation. Two forms of thalamic input zone-selective dysrhythmia manifested after dopamine depletion: (1) BZ neurons, but not CZ neurons, exhibited abnormal phase-shifted firing with respect to cortical slow oscillations prevalent during slow-wave activity; and (2) BZ neurons, but not CZ neurons, inappropriately synchronized their firing and engaged with the exaggerated cortical beta oscillations arising in activated states. These dysrhythmias were not accompanied by the thalamic hypoactivity predicted by canonical firing rate-based models of circuit organization in Parkinsonism. Complementary recordings of neurons in substantia nigra pars reticulata suggested that their altered activity dynamics could underpin the BZ dysrhythmias. Finally, pharmacological perturbations demonstrated that ongoing activity in the motor thalamus bolsters exaggerated beta oscillations in motor cortex. We conclude that BZ neurons are selectively primed to mediate the detrimental influences of abnormal slow and beta-band rhythms on circuit information processing in Parkinsonism.SIGNIFICANCE STATEMENT Motor thalamus neurons mediate the influences of basal ganglia and cerebellum on the cerebral cortex to govern movement. Chronic depletion of dopamine from the basal ganglia causes some symptoms of Parkinson's disease. Here, we elucidate how dopamine depletion alters the ways motor thalamus neurons engage with two distinct oscillations emerging in cortico-basal ganglia circuits in vivo We discovered that, after dopamine depletion, neurons in the thalamic zone receiving basal ganglia inputs are particularly prone to becoming dysrhythmic, changing the phases and/or synchronization (but not rate) of their action potential firing. This bolsters cortical dysrhythmia. Our results provide important new insights into how aberrant rhythmicity in select parts of motor thalamus could detrimentally affect neural circuit dynamics and behavior in Parkinsonism.
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Affiliation(s)
- Kouichi C Nakamura
- Medical Research Council Brain Network Dynamics Unit, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, OX1 3TH, United Kingdom
| | - Andrew Sharott
- Medical Research Council Brain Network Dynamics Unit, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, OX1 3TH, United Kingdom
| | - Takuma Tanaka
- Center for Data Science Education and Research, Shiga University, Hikone, Shiga 522-8522, Japan
| | - Peter J Magill
- Medical Research Council Brain Network Dynamics Unit, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, OX1 3TH, United Kingdom
- Oxford Parkinson's Disease Centre, University of Oxford, Oxford, OX1 3QX, United Kingdom
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5
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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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6
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Logiaco L, Abbott LF, Escola S. Thalamic control of cortical dynamics in a model of flexible motor sequencing. Cell Rep 2021; 35:109090. [PMID: 34077721 PMCID: PMC8449509 DOI: 10.1016/j.celrep.2021.109090] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 03/04/2021] [Accepted: 04/16/2021] [Indexed: 12/26/2022] Open
Abstract
The neural mechanisms that generate an extensible library of motor motifs and flexibly string them into arbitrary sequences are unclear. We developed a model in which inhibitory basal ganglia output neurons project to thalamic units that are themselves bidirectionally connected to a recurrent cortical network. We model the basal ganglia inhibitory patterns as silencing some thalamic neurons while leaving others disinhibited and free to interact with cortex during specific motifs. We show that a small number of disinhibited thalamic neurons can control cortical dynamics to generate specific motor output in a noise-robust way. Additionally, a single "preparatory" thalamocortical network can produce fast cortical dynamics that support rapid transitions between any pair of learned motifs. If the thalamic units associated with each sequence component are segregated, many motor outputs can be learned without interference and then combined in arbitrary orders for the flexible production of long and complex motor sequences.
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Affiliation(s)
- Laureline Logiaco
- Zuckerman Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA; Zuckerman Institute, Department of Psychiatry, Columbia University, New York, NY 10027, USA.
| | - L F Abbott
- Zuckerman Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA
| | - Sean Escola
- Zuckerman Institute, Department of Psychiatry, Columbia University, New York, NY 10027, USA
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7
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Changes in Excitability Properties of Ventromedial Motor Thalamic Neurons in 6-OHDA Lesioned Mice. eNeuro 2021; 8:ENEURO.0436-20.2021. [PMID: 33509950 PMCID: PMC7920540 DOI: 10.1523/eneuro.0436-20.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Revised: 01/19/2021] [Accepted: 01/24/2021] [Indexed: 12/12/2022] Open
Abstract
The activity of basal ganglia input receiving motor thalamus (BGMT) makes a critical impact on motor cortical processing, but modification in BGMT processing with Parkinsonian conditions has not be investigated at the cellular level. Such changes may well be expected because of homeostatic regulation of neural excitability in the presence of altered synaptic drive with dopamine depletion. We addressed this question by comparing BGMT properties in brain slice recordings between control and unilaterally 6-hydroxydopamine hydrochloride (6-OHDA)-treated adult mice. At a minimum of one month after 6-OHDA treatment, BGMT neurons showed a highly significant increase in intrinsic excitability, which was primarily because of a decrease in M-type potassium current. BGMT neurons after 6-OHDA treatment also showed an increase in T-type calcium rebound spikes following hyperpolarizing current steps. Biophysical computer modeling of a thalamic neuron demonstrated that an increase in rebound spiking can also be accounted for by a decrease in the M-type potassium current. Modeling also showed that an increase in sag with hyperpolarizing steps found after 6-OHDA treatment could in part but not fully be accounted for by the decrease in M-type current. These findings support the hypothesis that homeostatic changes in BGMT neural properties following 6-OHDA treatment likely influence the signal processing taking place in the BG thalamocortical network in Parkinson’s disease.
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8
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Firing Differences Between Adult Intralaminar Thalamo-striatal Neurons. Neuroscience 2021; 458:153-165. [PMID: 33428968 DOI: 10.1016/j.neuroscience.2020.12.032] [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: 09/12/2020] [Revised: 12/08/2020] [Accepted: 12/27/2020] [Indexed: 11/23/2022]
Abstract
Differences in the intrinsic properties of intralaminar thalamo-striatal neurons such as expressing low-threshold-spikes (LTS) or after hyperpolarizing potentials (AHPs) of different duration have been attributed to different maturation stages. However, two morphological types: "diffuse" and "bushy" have been described. Therefore, we explored whether electrophysiological differences persist in adult mice using whole cell recordings. Some recorded neurons were identified by intracellular labeling with biocytin and double labeling with retrograde or anterograde tracings using Cre-mice. We classified these neurons by their AHPs during spontaneous firing. Neurons with long duration AHPs, with fast and slow components, were mostly found in the parafascicular (Pf) nucleus. Neurons with brief AHPs were mainly found in the central lateral (CL) nucleus. However, neurons with both AHPs were found in both nuclei in different proportions. Firing frequency adaptation differed between these neuron classes: those with prolonged AHPs exhibited firing frequency adaptation with fast and slow time constants whereas those with brief AHPs were slow adapters. Neurons with more prolonged AHPs had significant higher input resistances than neurons with brief AHPs. Both cell classes could fire in two modes: trains of single action potentials at depolarized potentials or high frequency bursts on top of LTS at more hyperpolarized potentials. LTS were probably generated by Cav3 calcium channels since they were blocked by the selective antagonist TTA-P2. About 11% of neurons with brief AHPs and 55% of neurons with prolonged AHPs do not show LTS and bursts, even when potassium currents are blocked.
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9
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Simple models including energy and spike constraints reproduce complex activity patterns and metabolic disruptions. PLoS Comput Biol 2020; 16:e1008503. [PMID: 33347433 PMCID: PMC7785241 DOI: 10.1371/journal.pcbi.1008503] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 01/05/2021] [Accepted: 11/09/2020] [Indexed: 12/23/2022] Open
Abstract
In this work, we introduce new phenomenological neuronal models (eLIF and mAdExp) that account for energy supply and demand in the cell as well as the inactivation of spike generation how these interact with subthreshold and spiking dynamics. Including these constraints, the new models reproduce a broad range of biologically-relevant behaviors that are identified to be crucial in many neurological disorders, but were not captured by commonly used phenomenological models. Because of their low dimensionality eLIF and mAdExp open the possibility of future large-scale simulations for more realistic studies of brain circuits involved in neuronal disorders. The new models enable both more accurate modeling and the possibility to study energy-associated disorders over the whole time-course of disease progression instead of only comparing the initially healthy status with the final diseased state. These models, therefore, provide new theoretical and computational methods to assess the opportunities of early diagnostics and the potential of energy-centered approaches to improve therapies. Neurons, even “at rest”, require a constant supply of energy to function. They cannot sustain high-frequency activity over long periods because of regulatory mechanisms, such as adaptation or sodium channels inactivation, and metabolic limitations. These limitations are especially severe in many neuronal disorders, where energy can become insufficient and make the neuronal response change drastically, leading to increased burstiness, network oscillations, or seizures. Capturing such behaviors and impact of energy constraints on them is an essential prerequisite to study disorders such as Parkinson’s disease and epilepsy. However, energy and spiking constraints are not present in any of the standard neuronal models used in computational neuroscience. Here we introduce models that provide a simple and scalable way to account for these features, enabling large-scale theoretical and computational studies of neurological disorders and activity patterns that could not be captured by previously used models. These models provide a way to study energy-associated disorders over the whole time-course of disease progression, and they enable a better assessment of energy-centered approaches to improve therapies.
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10
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Gaidica M, Hurst A, Cyr C, Leventhal DK. Interactions Between Motor Thalamic Field Potentials and Single-Unit Spiking Are Correlated With Behavior in Rats. Front Neural Circuits 2020; 14:52. [PMID: 32922268 PMCID: PMC7457120 DOI: 10.3389/fncir.2020.00052] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 07/16/2020] [Indexed: 11/30/2022] Open
Abstract
Field potential (FP) oscillations are believed to coordinate brain activity over large spatiotemporal scales, with specific features (e.g., phase and power) in discrete frequency bands correlated with motor output. Furthermore, complex correlations between oscillations in distinct frequency bands (phase-amplitude, amplitude-amplitude, and phase-phase coupling) are commonly observed. However, the mechanisms underlying FP-behavior correlations and cross-frequency coupling remain unknown. The thalamus plays a central role in generating many circuit-level neural oscillations, and single-unit activity in motor thalamus (Mthal) is correlated with behavioral output. We, therefore, hypothesized that motor thalamic spiking coordinates motor system FPs and underlies FP-behavior correlations. To investigate this possibility, we recorded wideband motor thalamic (Mthal) electrophysiology as healthy rats performed a two-alternative forced-choice task. Delta (1–4 Hz), beta (13–30 Hz), low gamma (30–70 Hz), and high gamma (70–200 Hz) power were strongly modulated by task performance. As in the cortex, the delta phase was correlated with beta/low gamma power and reaction time. Most interestingly, subpopulations of Mthal neurons defined by their relationship to the behavior exhibited distinct relationships with FP features. Specifically, neurons whose activity was correlated with action selection and movement speed were entrained to delta oscillations. Furthermore, changes in their activity anticipated power fluctuations in beta/low gamma bands. These complex relationships suggest mechanisms for commonly observed FP-FP and spike-FP correlations, as well as subcortical influences on motor output.
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Affiliation(s)
- Matt Gaidica
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, United States
| | - Amy Hurst
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States
| | - Christopher Cyr
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States
| | - Daniel K Leventhal
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States.,Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States.,Parkinson Disease Foundation Research Center of Excellence, University of Michigan, Ann Arbor, MI, United States.,Department of Neurology, VA Ann Arbor Health System, Ann Arbor, MI, United States
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11
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Whalen TC, Willard AM, Rubin JE, Gittis AH. Delta oscillations are a robust biomarker of dopamine depletion severity and motor dysfunction in awake mice. J Neurophysiol 2020; 124:312-329. [PMID: 32579421 PMCID: PMC7500379 DOI: 10.1152/jn.00158.2020] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 06/15/2020] [Accepted: 06/17/2020] [Indexed: 12/14/2022] Open
Abstract
Delta oscillations (0.5-4 Hz) are a robust feature of basal ganglia pathophysiology in patients with Parkinson's disease (PD) in relationship to tremor, but their relationship to other parkinsonian symptoms has not been investigated. While delta oscillations have been observed in mouse models of PD, they have only been investigated in anesthetized animals, suggesting that the oscillations may be an anesthesia artifact and limiting the ability to relate them to motor symptoms. Here, we establish a novel approach to detect spike oscillations embedded in noise to provide the first study of delta oscillations in awake, dopamine-depleted mice. We find that approximately half of neurons in the substantia nigra pars reticulata (SNr) exhibit delta oscillations in dopamine depletion and that these oscillations are a strong indicator of dopamine loss and akinesia, outperforming measures such as changes in firing rate, irregularity, bursting, and synchrony. These oscillations are typically weakened, but not ablated, during movement. We further establish that these oscillations are caused by the loss of D2-receptor activation and do not originate from motor cortex, contrary to previous findings in anesthetized animals. Instead, SNr oscillations precede those in M1 at a 100- to 300-ms lag, and these neurons' relationship to M1 oscillations can be used as the basis for a novel classification of SNr into two subpopulations. These results give insight into how dopamine loss leads to motor dysfunction and suggest a reappraisal of delta oscillations as a marker of akinetic symptoms in PD.NEW & NOTEWORTHY This work introduces a novel method to detect spike oscillations amidst neural noise. Using this method, we demonstrate that delta oscillations in the basal ganglia are a defining feature of awake, dopamine-depleted mice and are strongly correlated with dopamine loss and parkinsonian motor symptoms. These oscillations arise from a loss of D2-receptor activation and do not require motor cortex. Similar oscillations in human patients may be an underappreciated marker and target for Parkinson's disease (PD) treatment.
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Affiliation(s)
- Timothy C Whalen
- Center for the Neural Basis of Cognition, Carnegie Mellon University, Pittsburgh, Pennsylvania
- Neuroscience Institute and Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Amanda M Willard
- Center for the Neural Basis of Cognition, Carnegie Mellon University, Pittsburgh, Pennsylvania
- Neuroscience Institute and Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania
- Department of Biology and Geosciences, Clarion University, Clarion, Pennsylvania
| | - Jonathan E Rubin
- Center for the Neural Basis of Cognition, Carnegie Mellon University, Pittsburgh, Pennsylvania
- Department of Mathematics, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Aryn H Gittis
- Center for the Neural Basis of Cognition, Carnegie Mellon University, Pittsburgh, Pennsylvania
- Neuroscience Institute and Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, Pennsylvania
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12
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Pathophysiological roles and therapeutic potential of voltage-gated ion channels (VGICs) in pain associated with herpesvirus infection. Cell Biosci 2020; 10:70. [PMID: 32489585 PMCID: PMC7247163 DOI: 10.1186/s13578-020-00430-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 05/13/2020] [Indexed: 02/06/2023] Open
Abstract
Herpesvirus is ranked as one of the grand old members of all pathogens. Of all the viruses in the superfamily, Herpes simplex virus type 1 (HSV-1) is considered as a model virus for a variety of reasons. In a permissive non-neuronal cell culture, HSV-1 concludes the entire life cycle in approximately 18–20 h, encoding approximately 90 unique transcriptional units. In latency, the robust viral gene expression is suppressed in neurons by a group of noncoding RNA. Historically the lesions caused by the virus can date back to centuries ago. As a neurotropic pathogen, HSV-1 is associated with painful oral lesions, severe keratitis and lethal encephalitis. Transmission of pain signals is dependent on the generation and propagation of action potential in sensory neurons. T-type Ca2+ channels serve as a preamplifier of action potential generation. Voltage-gated Na+ channels are the main components for action potential production. This review summarizes not only the voltage-gated ion channels in neuropathic disorders but also provides the new insights into HSV-1 induced pain.
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13
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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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14
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Ottolini M, Hong K, Sonkusare SK. Calcium signals that determine vascular resistance. WILEY INTERDISCIPLINARY REVIEWS. SYSTEMS BIOLOGY AND MEDICINE 2019; 11:e1448. [PMID: 30884210 PMCID: PMC6688910 DOI: 10.1002/wsbm.1448] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Revised: 02/07/2019] [Accepted: 02/14/2019] [Indexed: 12/19/2022]
Abstract
Small arteries in the body control vascular resistance, and therefore, blood pressure and blood flow. Endothelial and smooth muscle cells in the arterial walls respond to various stimuli by altering the vascular resistance on a moment to moment basis. Smooth muscle cells can directly influence arterial diameter by contracting or relaxing, whereas endothelial cells that line the inner walls of the arteries modulate the contractile state of surrounding smooth muscle cells. Cytosolic calcium is a key driver of endothelial and smooth muscle cell functions. Cytosolic calcium can be increased either by calcium release from intracellular stores through IP3 or ryanodine receptors, or the influx of extracellular calcium through ion channels at the cell membrane. Depending on the cell type, spatial localization, source of a calcium signal, and the calcium-sensitive target activated, a particular calcium signal can dilate or constrict the arteries. Calcium signals in the vasculature can be classified into several types based on their source, kinetics, and spatial and temporal properties. The calcium signaling mechanisms in smooth muscle and endothelial cells have been extensively studied in the native or freshly isolated cells, therefore, this review is limited to the discussions of studies in native or freshly isolated cells. This article is categorized under: Biological Mechanisms > Cell Signaling Laboratory Methods and Technologies > Imaging Models of Systems Properties and Processes > Mechanistic Models.
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Affiliation(s)
- Matteo Ottolini
- Robert M. Berne Cardiovascular Research Center, University of Virginia-School of Medicine, Charlottesville, VA, 22908, USA
- Department of Pharmacology, University of Virginia-School of Medicine, Charlottesville, VA, 22908, USA
| | - Kwangseok Hong
- Robert M. Berne Cardiovascular Research Center, University of Virginia-School of Medicine, Charlottesville, VA, 22908, USA
- Department of Physical Education, Chung-Ang University, Seoul, 06974, South Korea
| | - Swapnil K. Sonkusare
- Robert M. Berne Cardiovascular Research Center, University of Virginia-School of Medicine, Charlottesville, VA, 22908, USA
- Department of Pharmacology, University of Virginia-School of Medicine, Charlottesville, VA, 22908, USA
- Department of Molecular Physiology and Biological Physics, University of Virginia-School of Medicine, Charlottesville, VA, 22908, USA
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15
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Abstract
INTRODUCTION T-type calcium channels are attractive targets for potential treatment of epilepsy inflammatory or neuropathic pain, insomnia, Parkinson's disease, and cancer. Three isoforms having different biophysical functions are expressed in peripheral and central nerve. Since the withdrawal of mibefradil, the first compound marketed for selective T-type calcium channel blockade, extensive efforts have been made to identify more selective T-type calcium channel blockers. AREAS COVERED This review covers the 43 patents describing 'organic small molecules as T-type calcium channel blockers'-published since 2012. The most recent similar patent review was published in 2011. Information from a recent review article and relevant research papers has been included, as well as biological data and clinical trial results where available. EXPERT OPINION Triazinone derivatives, carbazole compounds, and aryl triazole/imidazole amide derivatives display potent blockade activity α1H, α1G, and pan T-type calcium channel subtypes, respectively, though the specificity of the letter is still unsatisfactory. Nonetheless, improvements seen in the efficacy of compounds targeting α1H T-type calcium channels indicate significant progress. Ongoing clinical trials are for the candidates Z944 (Phase II) and ACT-709478 (Phase II) appear promising. These studies may lead to a new generation of inhibitors with higher selectivity, improved physicochemical properties, and reduced side effects.
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Affiliation(s)
- Ghilsoo Nam
- a Center for Neuro-Medicine , Brain Science Institute, Korea Institutes of Science and Technology (KIST) , Seoul , Republic of Korea.,b Division of Bio-Medical Science, KIST School , Korea University of Science and Technology Seoul , Seoul , Republic of Korea
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16
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Wang D, Ragnarsson L, Lewis RJ. T-type Calcium Channels in Health and Disease. Curr Med Chem 2018; 27:3098-3122. [PMID: 30277145 DOI: 10.2174/0929867325666181001112821] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 08/28/2018] [Accepted: 08/30/2018] [Indexed: 12/12/2022]
Abstract
Low Voltage-Activated (LVA) T-type calcium channels are characterized by transient current and Low Threshold Spikes (LTS) that trigger neuronal firing and oscillatory behavior. Combined with their preferential localization in dendrites and their specific "window current", T-type calcium channels are considered to be key players in signal amplification and synaptic integration. Assisted by the emerging pharmacological tools, the structural determinants of channel gating and kinetics, as well as novel physiological and pathological functions of T-type calcium channels, are being uncovered. In this review, we provide an overview of structural determinants in T-type calcium channels, their involvement in disorders and diseases, the development of novel channel modulators, as well as Structure-Activity Relationship (SAR) studies that lead to rational drug design.
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Affiliation(s)
- Dan Wang
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, the University of Queensland, Brisbane Qld 4072, Australia
| | - Lotten Ragnarsson
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, the University of Queensland, Brisbane Qld 4072, Australia
| | - Richard J Lewis
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, the University of Queensland, Brisbane Qld 4072, Australia
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17
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Bhattacharya S, Ma Y, Dunn AR, Bradner JM, Scimemi A, Miller GW, Traynelis SF, Wichmann T. NMDA receptor blockade ameliorates abnormalities of spike firing of subthalamic nucleus neurons in a parkinsonian nonhuman primate. J Neurosci Res 2018; 96:1324-1335. [PMID: 29577359 PMCID: PMC5980712 DOI: 10.1002/jnr.24230] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 01/25/2018] [Accepted: 02/08/2018] [Indexed: 12/21/2022]
Abstract
N-methyl-D-aspartate receptors (NMDARs) are ion channels comprising tetrameric assemblies of GluN1 and GluN2 receptor subunits that mediate excitatory neurotransmission in the central nervous system. Of the four different GluN2 subunits, the GluN2D subunit-containing NMDARs have been suggested as a target for antiparkinsonian therapy because of their expression pattern in some of the basal ganglia nuclei that show abnormal firing patterns in the parkinsonian state, specifically the subthalamic nucleus (STN). In this study, we demonstrate that blockade of NMDARs altered spike firing in the STN in a male nonhuman primate that had been rendered parkinsonian by treatment with the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. In accompanying experiments in male rodents, we found that GluN2D-NMDAR expression in the STN was reduced in acutely or chronically dopamine-depleted animals. Taken together, our data suggest that blockade of NMDARs in the STN may be a viable antiparkinsonian strategy, but that the ultimate success of this approach may be complicated by parkinsonism-associated changes in NMDAR expression in the STN.
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Affiliation(s)
| | - Yuxian Ma
- Yerkes National Primate Research Center, Emory University, Atlanta, Georgia
| | - Amy R Dunn
- Rollins School of Public Health, Emory University, Atlanta, Georgia
| | - Joshua M Bradner
- Rollins School of Public Health, Emory University, Atlanta, Georgia
| | - Annalisa Scimemi
- Department of Biology, State University of New York at Albany, Albany, New York
| | - Gary W Miller
- Rollins School of Public Health, Emory University, Atlanta, Georgia
| | - Stephen F Traynelis
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia
| | - Thomas Wichmann
- Yerkes National Primate Research Center, Emory University, Atlanta, Georgia
- Department of Neurology, Emory University School of Medicine, Atlanta, Georgia
- Morris K. Udall Center of Excellence for Parkinson's Disease Research at Emory University, Atlanta, Georgia
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18
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Galvan A, Devergnas A, Pittard D, Masilamoni G, Vuong J, Daniels JS, Morrison RD, Lindsley CW, Wichmann T. Lack of Antiparkinsonian Effects of Systemic Injections of the Specific T-Type Calcium Channel Blocker ML218 in MPTP-Treated Monkeys. ACS Chem Neurosci 2016; 7:1543-1551. [PMID: 27596273 DOI: 10.1021/acschemneuro.6b00186] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Dopaminergic medications ameliorate many of the motor impairments of Parkinson's disease (PD). However, parkinsonism is often only partially reversed by these drugs, and they can have significant side effects. Therefore, a need remains for novel treatments of parkinsonism. Studies in rodents and preliminary clinical evidence have shown that T-type calcium channel (TTCC) antagonists have antiparkinsonian effects. However, most of the available studies utilized nonselective agents. We now evaluated whether systemic injections of the specific TTCC blocker ML218 have antiparkinsonian effects in MPTP-treated parkinsonian Rhesus monkeys. The animals were treated chronically with MPTP until they reached stable parkinsonism. In pharmacokinetic studies, we found that ML218 reaches a peak CSF concentration 1-2 h after s.c. administration. In electrocardiographic studies, we found no effects of ML218 on cardiac rhythmicity. As expected, systemic injections of the dopamine precursor L-DOPA dose-dependently increased the movements in our parkinsonian animals. We then tested the behavioral effects of systemic injections of ML218 (1, 10, or 30 mg/kg) or its vehicle, but did not detect specific antiparkinsonian effects. ML218 (3 or 10 mg/kg) was also not synergistic with L-DOPA. Using recordings of electrocorticogram signals (in one animal), we found that ML218 increased sleep. We conclude that ML218 does not have antiparkinsonian effects in MPTP-treated parkinsonian monkeys, due at least in part, to the agent's sedative effects.
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Affiliation(s)
| | | | | | | | | | - J. Scott Daniels
- Department
of Pharmacology and Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Ryan D. Morrison
- Department
of Pharmacology and Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Craig W. Lindsley
- Department
of Pharmacology and Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
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19
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Chen E, Paré JF, Wichmann T, Smith Y. Sub-synaptic localization of Ca v3.1 T-type calcium channels in the thalamus of normal and parkinsonian monkeys. Brain Struct Funct 2016; 222:735-748. [PMID: 27255751 DOI: 10.1007/s00429-016-1242-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 05/20/2016] [Indexed: 11/25/2022]
Abstract
T-type calcium channels (Cav3) are key mediators of thalamic bursting activity, but also regulate single cells excitability, dendritic integration, synaptic strength and transmitter release. These functions are strongly influenced by the subcellular and subsynaptic localization of Cav3 channels along the somatodendritic domain of thalamic cells. In Parkinson's disease, T-type calcium channels dysfunction in the basal ganglia-receiving thalamic nuclei likely contributes to pathological thalamic bursting activity. In this study, we analyzed the cellular, subcellular, and subsynaptic localization of the Cav3.1 channel in the ventral anterior (VA) and centromedian/parafascicular (CM/Pf) thalamic nuclei, the main thalamic targets of basal ganglia output, in normal and parkinsonian monkeys. All thalamic nuclei displayed strong Cav3.1 neuropil immunoreactivity, although the intensity of immunolabeling in CM/Pf was significantly lower than in VA. Ultrastructurally, 70-80 % of the Cav3.1-immunoreactive structures were dendritic shafts. Using immunogold labeling, Cav3.1 was commonly found perisynaptic to asymmetric and symmetric axo-dendritic synapses, suggesting a role of Cav3.1 in regulating excitatory and inhibitory neurotransmission. Significant labeling was also found at non-synaptic sites along the plasma membrane of thalamic neurons. There was no difference in the overall pattern and intensity of immunostaining between normal and parkinsonian monkeys, suggesting that the increased rebound bursting in the parkinsonian state is not driven by changes in Cav3.1 expression. Thus, T-type calcium channels are located to subserve neuronal bursting, but also regulate glutamatergic and non-glutamatergic transmission along the whole somatodendritic domain of basal ganglia-receiving neurons of the primate thalamus.
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Affiliation(s)
- Erdong Chen
- Yerkes National Primate Research Center, Emory University, 954 Gatewood Road NE, Atlanta, GA, 30329, USA.,Udall Center of Excellence for Parkinson's Disease Research, Emory University, Atlanta, GA, 30322, USA
| | - Jean-Francois Paré
- Yerkes National Primate Research Center, Emory University, 954 Gatewood Road NE, Atlanta, GA, 30329, USA.,Udall Center of Excellence for Parkinson's Disease Research, Emory University, Atlanta, GA, 30322, USA
| | - Thomas Wichmann
- Yerkes National Primate Research Center, Emory University, 954 Gatewood Road NE, Atlanta, GA, 30329, USA.,Udall Center of Excellence for Parkinson's Disease Research, Emory University, Atlanta, GA, 30322, USA.,Department of Neurology, Emory University, Atlanta, GA, 30322, USA
| | - Yoland Smith
- Yerkes National Primate Research Center, Emory University, 954 Gatewood Road NE, Atlanta, GA, 30329, USA. .,Udall Center of Excellence for Parkinson's Disease Research, Emory University, Atlanta, GA, 30322, USA. .,Department of Neurology, Emory University, Atlanta, GA, 30322, USA.
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