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Blankenship HE, Carter KA, Cassidy NT, Markiewicz AN, Thellmann MI, Sharpe AL, Freeman WM, Beckstead MJ. VTA dopamine neurons are hyperexcitable in 3xTg-AD mice due to casein kinase 2-dependent SK channel dysfunction. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.16.567486. [PMID: 38014232 PMCID: PMC10680865 DOI: 10.1101/2023.11.16.567486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Alzheimer's disease (AD) patients exhibit neuropsychiatric symptoms that extend beyond classical cognitive deficits, suggesting involvement of subcortical areas. Here, we investigated the role of midbrain dopamine (DA) neurons in AD using the amyloid + tau-driven 3xTg-AD mouse model. We found deficits in reward-based operant learning in AD mice, suggesting possible VTA DA neuron dysregulation. Physiological assessment revealed hyperexcitability and disrupted firing in DA neurons caused by reduced activity of small-conductance calcium-activated potassium (SK) channels. RNA sequencing from contents of single patch-clamped DA neurons (Patch-seq) identified up-regulation of the SK channel modulator casein kinase 2 (CK2). Pharmacological inhibition of CK2 restored SK channel activity and normal firing patterns in 3xTg-AD mice. These findings shed light on a complex interplay between neuropsychiatric symptoms and subcortical circuits in AD, paving the way for novel treatment strategies.
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Bell D, Waldron VJ, Brown PL. Quantitative and qualitative sex difference in habenula-induced inhibition of midbrain dopamine neurons in the rat. Front Behav Neurosci 2023; 17:1289407. [PMID: 38025387 PMCID: PMC10679542 DOI: 10.3389/fnbeh.2023.1289407] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 10/30/2023] [Indexed: 12/01/2023] Open
Abstract
Introduction Clinically relevant sex differences have been noted in a number of affective, behavioral, cognitive, and neurological health disorders. Midbrain dopamine neurons are implicated in several of these same disorders and consequently are under investigation for their potential role in the manifestation of these sex differences. The lateral habenula exerts significant inhibitory control over dopamine neuronal firing, yet little is known about sex differences in this particular neurocircuit. Methods We performed in vivo, single unit, extracellular recordings of dopamine neurons in female and male anesthetized rats in response to single pulse stimulation of the lateral habenula. In addition, we assessed baseline firing properties of lateral habenula neurons and, by immunochemical means, assessed the distribution of estrogen receptor alpha cells in the lateral habenula. Results Habenula-induced inhibition of dopamine neuronal firing is reduced in female rats relative to male rats. In addition, male rats had a higher prevalence of rebound excitation. Furthermore, the firing pattern of lateral habenula neurons was less variable in female rats, and female rats had a higher density of estrogen receptor alpha positive cells in the lateral habenula. Discussion We found that the dopamine neuronal response to habenular stimulation is both qualitatively and quantitatively different in female and male rats. These novel findings together with reports in the contemporary literature lead us to posit that the sex difference in dopamine inhibition seen here relate to differential firing properties of lateral habenula neurons resulting from the presence of sex hormones. Further work is needed to test this hypothesis, which may have implications for understanding the etiology of several mental health disorders including depression, schizophrenia, and addiction.
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Affiliation(s)
| | | | - P. Leon Brown
- Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, United States
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Fang X, Chen Y, Wang J, Zhang Z, Bai Y, Denney K, Gan L, Guo M, Weintraub NL, Lei Y, Lu XY. Increased intrinsic and synaptic excitability of hypothalamic POMC neurons underlies chronic stress-induced behavioral deficits. Mol Psychiatry 2023; 28:1365-1382. [PMID: 36473997 PMCID: PMC10005948 DOI: 10.1038/s41380-022-01872-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 10/26/2022] [Accepted: 11/03/2022] [Indexed: 12/12/2022]
Abstract
Chronic stress exposure induces maladaptive behavioral responses and increases susceptibility to neuropsychiatric conditions. However, specific neuronal populations and circuits that are highly sensitive to stress and trigger maladaptive behavioral responses remain to be identified. Here we investigate the patterns of spontaneous activity of proopiomelanocortin (POMC) neurons in the arcuate nucleus (ARC) of the hypothalamus following exposure to chronic unpredictable stress (CUS) for 10 days, a stress paradigm used to induce behavioral deficits such as anhedonia and behavioral despair [1, 2]. CUS exposure increased spontaneous firing of POMC neurons in both male and female mice, attributable to reduced GABA-mediated synaptic inhibition and increased intrinsic neuronal excitability. While acute activation of POMC neurons failed to induce behavioral changes in non-stressed mice of both sexes, subacute (3 days) and chronic (10 days) repeated activation of POMC neurons was sufficient to induce anhedonia and behavioral despair in males but not females under non-stress conditions. Acute activation of POMC neurons promoted susceptibility to subthreshold unpredictable stress in both male and female mice. Conversely, acute inhibition of POMC neurons was sufficient to reverse CUS-induced anhedonia and behavioral despair in both sexes. Collectively, these results indicate that chronic stress induces both synaptic and intrinsic plasticity of POMC neurons, leading to neuronal hyperactivity. Our findings suggest that POMC neuron dysfunction drives chronic stress-related behavioral deficits.
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Affiliation(s)
- Xing Fang
- Department of Neuroscience & Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Yuting Chen
- Department of Neuroscience & Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Jiangong Wang
- Department of Neuroscience & Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Ziliang Zhang
- Department of Neuroscience & Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Yu Bai
- Department of Neuroscience & Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Kirstyn Denney
- Department of Neuroscience & Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Lin Gan
- Department of Neuroscience & Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Ming Guo
- Department of Neuroscience & Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Neal L Weintraub
- Department of Medicine, Vascular Biology Center, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Yun Lei
- Department of Neuroscience & Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Xin-Yun Lu
- Department of Neuroscience & Regenerative Medicine, Medical College of Georgia at Augusta University, Augusta, GA, USA.
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Bancroft EA, De La Mora M, Pandey G, Zarate SM, Srinivasan R. Extracellular S100B inhibits A-type voltage-gated potassium currents and increases L-type voltage-gated calcium channel activity in dopaminergic neurons. Glia 2022; 70:2330-2347. [PMID: 35916350 PMCID: PMC10738449 DOI: 10.1002/glia.24254] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 07/19/2022] [Accepted: 07/20/2022] [Indexed: 11/11/2022]
Abstract
Parkinson's disease (PD) is associated with an increase in secreted S100B within the midbrain and cerebrospinal fluid. In addition, S100B overexpression in mice accelerates the loss of substantia nigra pars compacta dopaminergic (DA) neurons, suggesting a role for this protein in PD pathogenesis. We found that in the mouse SNc, S100B labeled astrocytic processes completely envelop the somata of tyrosine hydroxylase (TH) expressing DA neurons only in male mice. These data suggest that an increase in S100B secretion by astrocytes within the midbrain could play a role in DA dysfunction during early PD. We therefore asked if acute exposure to extracellular S100B alters the activity of identified TH expressing DA neurons in primary mouse midbrain cultures. Acute exposure to 50 pM S100B specifically inhibited A-type voltage-gated potassium currents in TH+ , but not TH- neurons. This was accompanied by ~2-fold increases in the frequency of both intrinsic firing, as well as L-type voltage-gated calcium channel (VGCC)-mediated calcium fluxes only in TH+ neurons. Further, exposure to 100 μM 4-aminopyridine (4-AP), an A-type voltage-gated potassium channel inhibitor, mimicked the S100B mediated increase in intrinsic firing and L-type VGCC-mediated calcium fluxes in TH+ neurons. Taken together, our finding that extracellular S100B alters the activity of native DA neurons via an inhibition of A-type voltage-gated potassium channels has important implications for understanding the pathophysiology of early PD.
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Affiliation(s)
- Eric A. Bancroft
- Department of Neuroscience & Experimental Therapeutics, Texas A&M University School of Medicine, Bryan, Texas, USA
| | - Martha De La Mora
- Department of Neuroscience & Experimental Therapeutics, Texas A&M University School of Medicine, Bryan, Texas, USA
| | - Gauri Pandey
- Department of Neuroscience & Experimental Therapeutics, Texas A&M University School of Medicine, Bryan, Texas, USA
- Texas A&M Institute for Neuroscience (TAMIN), College Station, Texas, USA
| | - Sara M. Zarate
- Department of Neuroscience & Experimental Therapeutics, Texas A&M University School of Medicine, Bryan, Texas, USA
| | - Rahul Srinivasan
- Department of Neuroscience & Experimental Therapeutics, Texas A&M University School of Medicine, Bryan, Texas, USA
- Texas A&M Institute for Neuroscience (TAMIN), College Station, Texas, USA
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Neuropeptide apelin presented in the dopaminergic neurons modulates the neuronal excitability in the substantia nigra pars compacta. Neuropharmacology 2022; 219:109235. [PMID: 36041497 DOI: 10.1016/j.neuropharm.2022.109235] [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: 07/13/2022] [Revised: 08/19/2022] [Accepted: 08/22/2022] [Indexed: 11/24/2022]
Abstract
The dopaminergic neurons in the substantia nigra pars compacta are characterized by autonomous pacemaking activity. The spontaneous firing activity of nigral dopaminergic neurons plays an important role in physiological function and is essential for their survival. Importantly, the spontaneous firing activity may also be involved in the preferential vulnerability of the nigral dopaminergic neurons in Parkinson's disease (PD). The neuropeptide apelin was reported to exert neuroprotective effects in neurodegenerative diseases, including PD. And it was noticed that apelin modulates neuronal activity in some brain regions. The present study investigated the electrophysiological and behavioral effects of apelin in the substantia nigra. Double-labeling immunofluorescence showed that apelin was present in nigral dopaminergic neurons and that these neurons expressed apelin receptor APJ. Further single unit in vivo electrophysiological recordings revealed that endogenous apelin tonically increased the firing rate of nigral dopaminergic neurons in both normal and parkinsonian animals. Exogenous apelin-13 exerted excitatory effects on the majority of nigral dopaminergic neurons, yet reduced excitability in a subset of neurons. In addition, nigral application of apelin-13 increased motor activity in normal rats and blocking endogenous apelin reduced motor activity. Considering the involvement of the spontaneous firing activity of nigral dopaminergic neurons in the development of PD and the possibility that apelin acts in an autocrine manner on apelin receptors expressed by nigral dopaminergic neurons, the modulation of the spontaneous firing activity of nigral dopaminergic neurons by apelin may serve as a neuroprotective factor in PD.
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Davison A, Lux UT, Brandstätter JH, Babai N. T-Type Ca 2+ Channels Boost Neurotransmission in Mammalian Cone Photoreceptors. J Neurosci 2022; 42:6325-6343. [PMID: 35803735 PMCID: PMC9398539 DOI: 10.1523/jneurosci.1878-21.2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 06/13/2022] [Accepted: 06/22/2022] [Indexed: 11/21/2022] Open
Abstract
It is a commonly accepted view that light stimulation of mammalian photoreceptors causes a graded change in membrane potential instead of developing a spike. The presynaptic Ca2+ channels serve as a crucial link for the coding of membrane potential variations into neurotransmitter release. Cav1.4 L-type Ca2+ channels are expressed in photoreceptor terminals, but the complete pool of Ca2+ channels in cone photoreceptors appears to be more diverse. Here, we discovered, employing whole-cell patch-clamp recording from cone photoreceptor terminals in both sexes of mice, that their Ca2+ currents are composed of low- (T-type Ca2+ channels) and high- (L-type Ca2+ channels) voltage-activated components. Furthermore, Ca2+ channels exerted self-generated spike behavior in dark membrane potentials, and spikes were generated in response to light/dark transition. The application of fast and slow Ca2+ chelators revealed that T-type Ca2+ channels are located close to the release machinery. Furthermore, capacitance measurements indicated that they are involved in evoked vesicle release. Additionally, RT-PCR experiments showed the presence of Cav3.2 T-type Ca2+ channels in cone photoreceptors but not in rod photoreceptors. Altogether, we found several crucial functions of T-type Ca2+ channels, which increase the functional repertoire of cone photoreceptors. Namely, they extend cone photoreceptor light-responsive membrane potential range, amplify dark responses, generate spikes, increase intracellular Ca2+ levels, and boost synaptic transmission.SIGNIFICANCE STATEMENT Photoreceptors provide the first synapse for coding light information. The key elements in synaptic transmission are the voltage-sensitive Ca2+ channels. Here, we provide evidence that mouse cone photoreceptors express low-voltage-activated Cav3.2 T-type Ca2+ channels in addition to high-voltage-activated L-type Ca2+ channels. The presence of T-type Ca2+ channels in cone photoreceptors appears to extend their light-responsive membrane potential range, amplify dark response, generate spikes, increase intracellular Ca2+ levels, and boost synaptic transmission. By these functions, Cav3.2 T-type Ca2+ channels increase the functional repertoire of cone photoreceptors.
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Affiliation(s)
- Adam Davison
- Department of Biology, Animal Physiology/Neurobiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Uwe Thorsten Lux
- Department of Biology, Animal Physiology/Neurobiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Johann Helmut Brandstätter
- Department of Biology, Animal Physiology/Neurobiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Norbert Babai
- Department of Biology, Animal Physiology/Neurobiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
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Rahdar M, Hajisoltani R, Davoudi S, Karimi SA, Borjkhani M, Khatibi VA, Hosseinmardi N, Behzadi G, Janahmadi M. Alterations in the intrinsic discharge activity of CA1 pyramidal neurons associated with possible changes in the NADPH diaphorase activity in a rat model of autism induced by prenatal exposure to valproic acid. Brain Res 2022; 1792:148013. [PMID: 35841982 DOI: 10.1016/j.brainres.2022.148013] [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: 05/18/2022] [Revised: 06/24/2022] [Accepted: 07/10/2022] [Indexed: 11/02/2022]
Abstract
Autism spectrum disorder is a neurodevelopmental disorder characterized by sensory abnormalities, social skills impairment and cognitive deficits. Although recent evidence indicated that induction of autism-like behavior in animal models causes abnormal neuronal excitability, the impact of autism on neuronal properties is still an important issue. Thus, new findings at the cellular level may shed light on the pathophysiology of autism and may help to find effective treatment strategies. Here, we investigated the behavioral, electrophysiological and histochemical impacts of prenatal exposure to valproic acid (VPA) in rats. Findings revealed that VPA exposure caused a significant increase in the hot plate response latency. The novel object recognition ability was also impaired in VPA-exposed rats. Along with these behavioral alterations, neurons from VPA-exposed animals exhibited altered excitability features in response to depolarizing current injections relative to control neurons. In the VPA-exposed group, these changes consisted of a significant increase in the amplitude, evoked firing frequency and the steady-state standard deviation of spike timing of action potentials (APs). Moreover, the half-width, the AHP amplitude and the decay time constant of APs were significantly decreased in this group. These changes in the evoked electrophysiological properties were accompanied by intrinsic hyperexcitability and lower spike-frequency adaptation and also a significant increase in the number of NADPH-diaphorase stained neurons in the hippocampal CA1 area of the VPA-exposed rats. Taken together, findings demonstrate that abnormal nociception and recognition memory is associated with alterations in the neuronal responsiveness and nitrergic system in a rat model of autism-like.
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Affiliation(s)
- Mona Rahdar
- Department of Physiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Razieh Hajisoltani
- Physiology Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Shima Davoudi
- Department of Physiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Seyed Asaad Karimi
- Department of Physiology, School of Medicine, Hamadan University of Medical Sciences, Tehran, Iran
| | - Mehdi Borjkhani
- Department of Electrical Engineering, Urmia University of Technology, Urmia, Iran
| | - Vahid Ahli Khatibi
- Department of Physiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Narges Hosseinmardi
- Department of Physiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Gila Behzadi
- Department of Physiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mahyar Janahmadi
- Neuroscience Research Center, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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Guatteo E, Berretta N, Monda V, Ledonne A, Mercuri NB. Pathophysiological Features of Nigral Dopaminergic Neurons in Animal Models of Parkinson's Disease. Int J Mol Sci 2022; 23:ijms23094508. [PMID: 35562898 PMCID: PMC9102081 DOI: 10.3390/ijms23094508] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 04/16/2022] [Accepted: 04/18/2022] [Indexed: 12/21/2022] Open
Abstract
The degeneration of nigral dopaminergic neurons is considered the hallmark of Parkinson’s disease (PD), and it is triggered by different factors, including mitochondrial dysfunction, Lewy body accumulation, neuroinflammation, excitotoxicity and metal accumulation. Despite the extensive literature devoted to unravelling the signalling pathways involved in neuronal degeneration, little is known about the functional impairments occurring in these cells during illness progression. Of course, it is not possible to obtain direct information on the properties of the dopaminergic cells in patients. However, several data are available in the literature reporting changes in the function of these cells in PD animal models. In the present manuscript, we focus on dopaminergic neuron functional properties and summarize shared or peculiar features of neuronal dysfunction in different PD animal models at different stages of the disease in an attempt to design a picture of the functional modifications occurring in nigral dopaminergic neurons during disease progression preceding their eventual death.
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Affiliation(s)
- Ezia Guatteo
- Department of Motor Science and Wellness, University of Naples Parthenope, 80133 Naples, Italy; (E.G.); (V.M.)
- Experimental Neurology Laboratory, IRCCS Santa Lucia Foundation, 00143 Rome, Italy;
| | - Nicola Berretta
- Experimental Neurology Laboratory, IRCCS Santa Lucia Foundation, 00143 Rome, Italy;
| | - Vincenzo Monda
- Department of Motor Science and Wellness, University of Naples Parthenope, 80133 Naples, Italy; (E.G.); (V.M.)
| | - Ada Ledonne
- Experimental Neurology Laboratory, IRCCS Santa Lucia Foundation, 00143 Rome, Italy;
- Correspondence: (A.L.); (N.B.M.)
| | - Nicola Biagio Mercuri
- Experimental Neurology Laboratory, IRCCS Santa Lucia Foundation, 00143 Rome, Italy;
- Department of Systems Medicine, University of Rome Tor Vergata, 00143 Rome, Italy
- Correspondence: (A.L.); (N.B.M.)
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Afterhyperpolarization Promotes the Firing of Mitral Cells through a Voltage-Dependent Modification of Action Potential Threshold. eNeuro 2022; 9:ENEURO.0401-21.2021. [PMID: 35277450 PMCID: PMC8982644 DOI: 10.1523/eneuro.0401-21.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 11/22/2021] [Accepted: 12/13/2021] [Indexed: 11/21/2022] Open
Abstract
In the olfactory bulb, mitral cells (MCs) display a spontaneous firing that is characterized by bursts of action potentials (APs) intermixed with silent periods. Intraburst firing frequency and duration are heterogeneous among MCs and increase with membrane depolarization. By using patch-clamp recording on rat slices, we dissected out the intrinsic properties responsible for this bursting activity. We showed that the threshold of AP generation dynamically changes as a function of the preceding trajectory of the membrane potential. In fact, the AP threshold became more negative when the membrane was hyperpolarized and had a recovery rate inversely proportional to the membrane repolarization rate. Such variations appeared to be produced by changes in the inactivation state of voltage-dependent Na+ channels. Thus, AP initiation was favored by hyperpolarizing events, such as negative membrane oscillations or inhibitory synaptic input. After the first AP, the following fast afterhyperpolarization (AHP) brought the threshold to more negative values and then promoted the emission of the following AP. This phenomenon was repeated for each AP of the burst making the fast AHP a regenerative mechanism that sustained the firing, AHP with larger amplitudes and faster repolarizations being associated with larger and higher-frequency bursts. Burst termination was found to be because of the development of a slow repolarization component of the AHP (slow AHP). Overall, the AHP characteristics appeared as a major determinant of the bursting properties.
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Yan Q, Wu X, Zhou P, Zhou Y, Li X, Liu Z, Tan H, Yao W, Xia Y, Zhu F. HERV-W Envelope Triggers Abnormal Dopaminergic Neuron Process through DRD2/PP2A/AKT1/GSK3 for Schizophrenia Risk. Viruses 2022; 14:v14010145. [PMID: 35062349 PMCID: PMC8777930 DOI: 10.3390/v14010145] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 01/08/2022] [Accepted: 01/10/2022] [Indexed: 12/13/2022] Open
Abstract
An increasing number of studies have begun considering human endogenous retroviruses (HERVs) as potential pathogenic phenomena. Our previous research suggests that HERV-W Envelope (HERV-W ENV), a HERV-W family envelope protein, is elevated in schizophrenia patients and contributes to the pathophysiology of schizophrenia. The dopamine (DA) hypothesis is the cornerstone in research and clinical practice related to schizophrenia. Here, we found that the concentration of DA and the expression of DA receptor D2 (DRD2) were significantly higher in schizophrenia patients than in healthy individuals. Intriguingly, there was a positive correlation between HERV-W ENV and DA concentration. Depth analyses showed that there was a marked consistency between HERV-W ENV and DRD2 in schizophrenia. Studies in vitro indicated that HERV-W ENV could increase the DA concentration by regulating DA metabolism and induce the expression of DRD2. Co-IP assays and laser confocal scanning microscopy indicated cellular colocalization and a direct interaction between DRD2 and HERV-W ENV. Additionally, HERV-W ENV caused structural and functional abnormalities of DA neurons. Further studies showed that HERV-W ENV could trigger the PP2A/AKT1/GSK3 pathway via DRD2. A whole-cell patch-clamp analysis suggested that HERV-W ENV enhanced sodium influx through DRD2. In conclusion, we uncovered a relationship between HERV-W ENV and the dopaminergic system in the DA neurons. Considering that GNbAC1, a selective monoclonal antibody to the MSRV-specific epitope, has been promised as a therapy for treating type 1 diabetes and multiple sclerosis (MS) in clinical trials, understanding the precise function of HERV-W ENV in the dopaminergic system may provide new insights into the treatment of schizophrenia.
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Affiliation(s)
- Qiujin Yan
- State Key Laboratory of Virology, Department of Medical Microbiology, School of Basic Medical Sciences, Wuhan University, Wuhan 430071, China; (Q.Y.); (X.W.); (P.Z.); (Y.Z.); (X.L.); (W.Y.); (Y.X.)
| | - Xiulin Wu
- State Key Laboratory of Virology, Department of Medical Microbiology, School of Basic Medical Sciences, Wuhan University, Wuhan 430071, China; (Q.Y.); (X.W.); (P.Z.); (Y.Z.); (X.L.); (W.Y.); (Y.X.)
| | - Ping Zhou
- State Key Laboratory of Virology, Department of Medical Microbiology, School of Basic Medical Sciences, Wuhan University, Wuhan 430071, China; (Q.Y.); (X.W.); (P.Z.); (Y.Z.); (X.L.); (W.Y.); (Y.X.)
| | - Yan Zhou
- State Key Laboratory of Virology, Department of Medical Microbiology, School of Basic Medical Sciences, Wuhan University, Wuhan 430071, China; (Q.Y.); (X.W.); (P.Z.); (Y.Z.); (X.L.); (W.Y.); (Y.X.)
| | - Xuhang Li
- State Key Laboratory of Virology, Department of Medical Microbiology, School of Basic Medical Sciences, Wuhan University, Wuhan 430071, China; (Q.Y.); (X.W.); (P.Z.); (Y.Z.); (X.L.); (W.Y.); (Y.X.)
| | - Zhongchun Liu
- Department of Psychiatry, Renmin Hospital of Wuhan University, Wuhan 430060, China; (Z.L.); (H.T.)
| | - Huawei Tan
- Department of Psychiatry, Renmin Hospital of Wuhan University, Wuhan 430060, China; (Z.L.); (H.T.)
| | - Wei Yao
- State Key Laboratory of Virology, Department of Medical Microbiology, School of Basic Medical Sciences, Wuhan University, Wuhan 430071, China; (Q.Y.); (X.W.); (P.Z.); (Y.Z.); (X.L.); (W.Y.); (Y.X.)
| | - Yaru Xia
- State Key Laboratory of Virology, Department of Medical Microbiology, School of Basic Medical Sciences, Wuhan University, Wuhan 430071, China; (Q.Y.); (X.W.); (P.Z.); (Y.Z.); (X.L.); (W.Y.); (Y.X.)
| | - Fan Zhu
- State Key Laboratory of Virology, Department of Medical Microbiology, School of Basic Medical Sciences, Wuhan University, Wuhan 430071, China; (Q.Y.); (X.W.); (P.Z.); (Y.Z.); (X.L.); (W.Y.); (Y.X.)
- Hubei Province Key Laboratory of Allergy & Immunology, Wuhan University, Wuhan 430071, China
- Correspondence:
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Biophysical and synaptic properties of regular spiking interneurons in hippocampal area CA3 of aged rats. Neurobiol Aging 2021; 112:27-38. [PMID: 35041997 DOI: 10.1016/j.neurobiolaging.2021.12.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 12/20/2021] [Accepted: 12/22/2021] [Indexed: 12/11/2022]
Abstract
Neuronal processing from the dentate gyrus to the hippocampus is critical for storage and recovery of new memory traces. In area CA3, GABAergic interneurons form a strong barrage of inhibition that modulates pyramidal cells. A well-established feature of aging is decreased GABAergic inhibition, a phenomenon that contributes to the exacerbated excitability of aged pyramidal cells. In hippocampal slices of aged rats (22-28 months old) we examined the properties of regular spiking CA3 interneurons with patch-clamp whole-cell recordings. We found enhanced firing discharge without altering the maximal firing rate of aged regular spiking interneurons. In the mossy fibers (MF) to interneurons synapse, a switch in the AMPA receptor subunit composition was found in aged interneurons. Young regular spiking interneurons predominantly express CP AMPA receptors and MF LTD. By contrast, aged regular spiking interneurons contain a higher proportion of CI AMPA receptors and respond with MF LTP. We show for the first time that the specialized MF terminals contacting interneurons, retain synaptic capabilities and provide a novel insight of the interneuron's function during aging.
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12
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Grimaldi S, El Mendili MM, Zaaraoui W, Ranjeva JP, Azulay JP, Eusebio A, Guye M. Increased Sodium Concentration in Substantia Nigra in Early Parkinson's Disease: A Preliminary Study With Ultra-High Field (7T) MRI. Front Neurol 2021; 12:715618. [PMID: 34566858 PMCID: PMC8458803 DOI: 10.3389/fneur.2021.715618] [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: 05/27/2021] [Accepted: 08/17/2021] [Indexed: 11/13/2022] Open
Abstract
Pathophysiology of idiopathic Parkinson's disease (iPD) is complex and still misunderstood. At a time when treatments with disease-modifying potential are being developed, identification of early markers of neurodegeneration is essential. Intracerebral sodium accumulation could be one of them. Indeed, it may be in relation to the mitochondrial dysfunction that early exists in iPD. For the first time, we used brain sodium (23Na) MRI to explore sodium concentration changes that have already been reported to be related to neurodegeneration in other diseases. We prospectively included 10 iPD patients (mean age 52.2 ± 5.9 years-old) with motor symptoms that started <36 months before inclusion and 12 healthy subjects (mean age 53 ± 6.4 years-old). Patients were scanned in OFF medication state by using proton (1H) and 23Na MRI at 7T. We then extracted quantitative Total Sodium Concentration (TSC) from five regions of interest known to be early impaired in iPD [substantia nigra (SN), putamen, caudate nucleus, pallidum, thalamus] and in one region supposed to be relatively spared in the first stages of the disease [cortical gray matter (neocortex)]. Potential atrophy in these structures was also investigated with 1H MRI. Relative to healthy subjects, iPD patients showed higher TSC in the SN (43.73 ± 4.64 vs. 37.72 ± 5.62, p = 0.006 after Bonferroni correction). A trend of increase in sodium concentrations was found within the pallidum (45.80 ± 4.19 vs. 41.07 ± 4.94, p = 0.017), putamen (48.65 ± 4.58 vs. 43.66 ± 5.04, p = 0.041) and the cortical gray matter (56.34 ± 3.92 vs. 50.81 ± 5.50, p = 0.021). No significant brain atrophy was found in patients compared to controls. Thus, alteration of sodium homeostasis in the SN in the absence of atrophy could be considered as a potential early marker of cellular dysfunction in iPD.
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Affiliation(s)
- Stephan Grimaldi
- APHM, Hôpital Universitaire Timone, Department of Neurology and Movement Disorders, Marseille, France.,APHM, Hôpital Universitaire Timone, CEMEREM, Marseille, France.,Aix Marseille Univ, CRMBM, CNRS, Marseille, France
| | - Mohamed Mounir El Mendili
- APHM, Hôpital Universitaire Timone, CEMEREM, Marseille, France.,Aix Marseille Univ, CRMBM, CNRS, Marseille, France
| | - Wafaa Zaaraoui
- APHM, Hôpital Universitaire Timone, CEMEREM, Marseille, France.,Aix Marseille Univ, CRMBM, CNRS, Marseille, France
| | - Jean-Philippe Ranjeva
- APHM, Hôpital Universitaire Timone, CEMEREM, Marseille, France.,Aix Marseille Univ, CRMBM, CNRS, Marseille, France
| | - Jean-Philippe Azulay
- APHM, Hôpital Universitaire Timone, Department of Neurology and Movement Disorders, Marseille, France
| | - Alexandre Eusebio
- APHM, Hôpital Universitaire Timone, Department of Neurology and Movement Disorders, Marseille, France.,Aix Marseille Univ, CNRS, Institut de Neurosciences de la Timone, Marseille, France
| | - Maxime Guye
- APHM, Hôpital Universitaire Timone, CEMEREM, Marseille, France.,Aix Marseille Univ, CRMBM, CNRS, Marseille, France
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13
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Riquelme D, Peralta FA, Navarro FD, Moreno C, Leiva-Salcedo E. I CAN (TRPM4) Contributes to the Intrinsic Excitability of Prefrontal Cortex Layer 2/3 Pyramidal Neurons. Int J Mol Sci 2021; 22:ijms22105268. [PMID: 34067824 PMCID: PMC8157065 DOI: 10.3390/ijms22105268] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 05/11/2021] [Accepted: 05/14/2021] [Indexed: 01/17/2023] Open
Abstract
Pyramidal neurons in the medial prefrontal cortical layer 2/3 are an essential contributor to the cellular basis of working memory; thus, changes in their intrinsic excitability critically affect medial prefrontal cortex (mPFC) functional properties. Transient Receptor Potential Melastatin 4 (TRPM4), a calcium-activated nonselective cation channel (CAN), regulates the membrane potential in a calcium-dependent manner. In this study, we uncovered the role of TRPM4 in regulating the intrinsic excitability plasticity of pyramidal neurons in the mouse mPFC layer of 2/3 using a combination of conventional and nystatin perforated whole-cell recordings. Interestingly, we found that TRPM4 is open at resting membrane potential, and its inhibition increases input resistance and hyperpolarizes membrane potential. After high-frequency stimulation, pyramidal neurons increase a calcium-activated non-selective cation current, increase the action potential firing, and the amplitude of the afterdepolarization, these effects depend on intracellular calcium. Furthermore, pharmacological inhibition or genetic silencing of TRPM4 reduces the firing rate and the afterdepolarization after high frequency stimulation. Together, these results show that TRPM4 plays a significant role in the excitability of mPFC layer 2/3 pyramidal neurons by modulating neuronal excitability in a calcium-dependent manner.
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14
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La Barbera L, Vedele F, Nobili A, Krashia P, Spoleti E, Latagliata EC, Cutuli D, Cauzzi E, Marino R, Viscomi MT, Petrosini L, Puglisi-Allegra S, Melone M, Keller F, Mercuri NB, Conti F, D'Amelio M. Nilotinib restores memory function by preventing dopaminergic neuron degeneration in a mouse model of Alzheimer's Disease. Prog Neurobiol 2021; 202:102031. [PMID: 33684513 DOI: 10.1016/j.pneurobio.2021.102031] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 02/15/2021] [Accepted: 02/28/2021] [Indexed: 01/18/2023]
Abstract
What happens precociously to the brain destined to develop Alzheimer's Disease (AD) still remains to be elucidated and this is one reason why effective AD treatments are missing. Recent experimental and clinical studies indicate that the degeneration of the dopaminergic (DA) neurons in the Ventral Tegmental Area (VTA) could be one of the first events occurring in AD. However, the causes of the increased vulnerability of DA neurons in AD are missing. Here, we deeply investigate the physiology of DA neurons in the VTA before, at the onset, and after onset of VTA neurodegeneration. We use the Tg2576 mouse model of AD, overexpressing a mutated form of the human APP, to identify molecular targets that can be manipulated pharmacologically. We show that in Tg2576 mice, DA neurons of the VTA at the onset of degeneration undergo slight but functionally relevant changes in their electrophysiological properties and cell morphology. Importantly, these changes are associated with accumulation of autophagosomes, suggestive of a dysfunctional autophagy, and with enhanced activation of c-Abl, a tyrosine kinase previously implicated in the pathogenesis of neurodegenerative diseases. Chronic treatment of Tg2576 mice with Nilotinib, a validated c-Abl inhibitor, reduces c-Abl phosphorylation, improves autophagy, reduces Aβ levels and - more importantly - prevents degeneration as well as functional and morphological alterations in DA neurons of the VTA. Interestingly, the drug prevents the reduction of DA outflow to the hippocampus and ameliorates hippocampal-related cognitive functions. Our results strive to identify early pathological brain changes in AD, to provide a rational basis for new therapeutic interventions able to slow down the disease progression.
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Affiliation(s)
- Livia La Barbera
- Department of Medicine and Surgery, Department of Sciences and Technologies for Humans and Environment, University Campus Bio-Medico, 00128, Rome, Italy; Department of Experimental Neurosciences, IRCCS Santa Lucia Foundation, 00143, Rome, Italy
| | - Francescangelo Vedele
- Department of Experimental Neurosciences, IRCCS Santa Lucia Foundation, 00143, Rome, Italy; Department of Systems Medicine, University of Rome Tor Vergata, 00133, Rome, Italy
| | - Annalisa Nobili
- Department of Medicine and Surgery, Department of Sciences and Technologies for Humans and Environment, University Campus Bio-Medico, 00128, Rome, Italy; Department of Experimental Neurosciences, IRCCS Santa Lucia Foundation, 00143, Rome, Italy
| | - Paraskevi Krashia
- Department of Medicine and Surgery, Department of Sciences and Technologies for Humans and Environment, University Campus Bio-Medico, 00128, Rome, Italy; Department of Experimental Neurosciences, IRCCS Santa Lucia Foundation, 00143, Rome, Italy.
| | - Elena Spoleti
- Department of Medicine and Surgery, Department of Sciences and Technologies for Humans and Environment, University Campus Bio-Medico, 00128, Rome, Italy
| | | | - Debora Cutuli
- Department of Experimental Neurosciences, IRCCS Santa Lucia Foundation, 00143, Rome, Italy; Department of Psychology, Sapienza University of Rome, 00185, Rome, Italy
| | - Emma Cauzzi
- Department of Medicine and Surgery, Department of Sciences and Technologies for Humans and Environment, University Campus Bio-Medico, 00128, Rome, Italy; School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Ramona Marino
- Department of Medicine and Surgery, Department of Sciences and Technologies for Humans and Environment, University Campus Bio-Medico, 00128, Rome, Italy
| | - Maria Teresa Viscomi
- Department of Experimental Neurosciences, IRCCS Santa Lucia Foundation, 00143, Rome, Italy; Department of Life Science and Public Health Section of Histology and Embryology, Università Cattolica del Sacro Cuore, 00168, Rome, Italy
| | - Laura Petrosini
- Department of Experimental Neurosciences, IRCCS Santa Lucia Foundation, 00143, Rome, Italy
| | | | - Marcello Melone
- Section of Neuroscience and Cell Biology, Department of Experimental and Clinical Medicine, Università Politecnica delle Marche (UNIVPM), 60020, Ancona, Italy; Center for Neurobiology of Aging, IRCCS Istituto Nazionale Ricovero e Cura Anziani (INRCA), 60020, Ancona, Italy
| | - Flavio Keller
- Department of Medicine and Surgery, Department of Sciences and Technologies for Humans and Environment, University Campus Bio-Medico, 00128, Rome, Italy
| | - Nicola Biagio Mercuri
- Department of Experimental Neurosciences, IRCCS Santa Lucia Foundation, 00143, Rome, Italy; Department of Systems Medicine, University of Rome Tor Vergata, 00133, Rome, Italy
| | - Fiorenzo Conti
- Section of Neuroscience and Cell Biology, Department of Experimental and Clinical Medicine, Università Politecnica delle Marche (UNIVPM), 60020, Ancona, Italy; Center for Neurobiology of Aging, IRCCS Istituto Nazionale Ricovero e Cura Anziani (INRCA), 60020, Ancona, Italy; Foundation for Molecular Medicine, Università Politecnica delle Marche, 60020, Ancona, Italy
| | - Marcello D'Amelio
- Department of Medicine and Surgery, Department of Sciences and Technologies for Humans and Environment, University Campus Bio-Medico, 00128, Rome, Italy; Department of Experimental Neurosciences, IRCCS Santa Lucia Foundation, 00143, Rome, Italy.
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15
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Simkin D, Marshall KA, Vanoye CG, Desai RR, Bustos BI, Piyevsky BN, Ortega JA, Forrest M, Robertson GL, Penzes P, Laux LC, Lubbe SJ, Millichap JJ, George AL, Kiskinis E. Dyshomeostatic modulation of Ca 2+-activated K + channels in a human neuronal model of KCNQ2 encephalopathy. eLife 2021; 10:64434. [PMID: 33544076 PMCID: PMC7864629 DOI: 10.7554/elife.64434] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 01/20/2021] [Indexed: 12/22/2022] Open
Abstract
Mutations in KCNQ2, which encodes a pore-forming K+ channel subunit responsible for neuronal M-current, cause neonatal epileptic encephalopathy, a complex disorder presenting with severe early-onset seizures and impaired neurodevelopment. The condition is exceptionally difficult to treat, partially because the effects of KCNQ2 mutations on the development and function of human neurons are unknown. Here, we used induced pluripotent stem cells (iPSCs) and gene editing to establish a disease model and measured the functional properties of differentiated excitatory neurons. We find that patient iPSC-derived neurons exhibit faster action potential repolarization, larger post-burst afterhyperpolarization and a functional enhancement of Ca2+-activated K+ channels. These properties, which can be recapitulated by chronic inhibition of M-current in control neurons, facilitate a burst-suppression firing pattern that is reminiscent of the interictal electroencephalography pattern in patients. Our findings suggest that dyshomeostatic mechanisms compound KCNQ2 loss-of-function leading to alterations in the neurodevelopmental trajectory of patient iPSC-derived neurons.
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Affiliation(s)
- Dina Simkin
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States.,Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Kelly A Marshall
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Carlos G Vanoye
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Reshma R Desai
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Bernabe I Bustos
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Brandon N Piyevsky
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Juan A Ortega
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Marc Forrest
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, United States.,Center for Autism and Neurodevelopment, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Gabriella L Robertson
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Peter Penzes
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, United States.,Center for Autism and Neurodevelopment, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Linda C Laux
- Epilepsy Center and Division of Neurology, Departments of Pediatrics and Neurology, Ann & Robert H. Lurie Children's Hospital of Chicago, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Steven J Lubbe
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - John J Millichap
- Epilepsy Center and Division of Neurology, Departments of Pediatrics and Neurology, Ann & Robert H. Lurie Children's Hospital of Chicago, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Alfred L George
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Evangelos Kiskinis
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States.,Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, United States
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16
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Chronic unpredictable stress induces depression-related behaviors by suppressing AgRP neuron activity. Mol Psychiatry 2021; 26:2299-2315. [PMID: 33432188 PMCID: PMC8272726 DOI: 10.1038/s41380-020-01004-x] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 12/13/2020] [Accepted: 12/15/2020] [Indexed: 02/06/2023]
Abstract
Previous studies have shown that AgRP neurons in the arcuate nucleus (ARC) respond to energy deficits and play a key role in the control of feeding behavior and metabolism. Here, we demonstrate that chronic unpredictable stress, an animal model of depression, decreases spontaneous firing rates, increases firing irregularity and alters the firing properties of AgRP neurons in both male and female mice. These changes are associated with enhanced inhibitory synaptic transmission and reduced intrinsic neuronal excitability. Chemogenetic inhibition of AgRP neurons increases susceptibility to subthreshold unpredictable stress. Conversely, chemogenetic activation of AgRP neurons completely reverses anhedonic and despair behaviors induced by chronic unpredictable stress. These results indicate that chronic stress induces maladaptive synaptic and intrinsic plasticity, leading to hypoactivity of AgRP neurons and subsequently causing behavioral changes. Our findings suggest that AgRP neurons in the ARC are a key component of neural circuitry involved in mediating depression-related behaviors and that increasing AgRP neuronal activity coule be a novel and effective treatment for depression.
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17
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Zampese E, Surmeier DJ. Calcium, Bioenergetics, and Parkinson's Disease. Cells 2020; 9:cells9092045. [PMID: 32911641 PMCID: PMC7564460 DOI: 10.3390/cells9092045] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 09/04/2020] [Accepted: 09/07/2020] [Indexed: 12/12/2022] Open
Abstract
Degeneration of substantia nigra (SN) dopaminergic (DAergic) neurons is responsible for the core motor deficits of Parkinson’s disease (PD). These neurons are autonomous pacemakers that have large cytosolic Ca2+ oscillations that have been linked to basal mitochondrial oxidant stress and turnover. This review explores the origin of Ca2+ oscillations and their role in the control of mitochondrial respiration, bioenergetics, and mitochondrial oxidant stress.
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18
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Marcantoni A, Cerullo MS, Buxeda P, Tomagra G, Giustetto M, Chiantia G, Carabelli V, Carbone E. Amyloid Beta42 oligomers up-regulate the excitatory synapses by potentiating presynaptic release while impairing postsynaptic NMDA receptors. J Physiol 2020; 598:2183-2197. [PMID: 32246769 DOI: 10.1113/jp279345] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 03/26/2020] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS NMDA receptors (NMDARs) are key molecules for controlling neuronal plasticity, learning and memory processes. Their function is impaired during Alzheimer's disease (AD) but the exact consequence on synaptic function is not yet fully identified. An important hallmark of AD onset is represented by the neuronal accumulation of Amyloid Beta42 oligomers (Abeta42) that we have recently shown to be responsible for the increased intracellular Ca2+ concentration through ryanodine receptors (RyRs). Here we characterized the effects of Abeta42 on NMDA synapses showing specific pre- and post-synaptic functional changes that lead to a potentiation of basal and synchronous NMDA synaptic transmission. These overall effects can be abolished by decreasing Ca2+ release from RyRs with specific inhibitors that we propose as new pharmacological tools for AD treatment. ABSTRACT We have recently shown that Amyloid Beta42 oligomers (Abeta42) cause calcium dysregulation in hippocampal neurons by stimulating Ca2+ release from ryanodine receptors (RyRs) and inhibiting Ca2+ entry through NMDA receptors (NMDARs). Here, we found that Abeta42 decrease the average NMDA-activated inward current and that Ca2+ entry through NMDARs is accompanied by Ca2+ release from the stores. The overall amount of intraellular Ca2+ concentration([Ca2+ ]i ) increase during NMDA application is 50% associated with RyR opening and 50% with NMDARs activation. Addition of Abeta42 does not change this proportion. We estimated the number of NMDARs expressed in hippocampal neurons and their unitary current. We found that Abeta42 decrease the number of NMDARs without altering their unitary current. Paradoxically, the oligomer increases the size of electrically evoked eEPSCs induced by NMDARs activation. We found that this is the consequence of the increased release probability (p) of glutamate and the number of release sites (N) of NMDA synapses, while the quantal size (q) is significantly decreased as expected from the decreased number of NMDARs. An increased number of release sites induced by Abeta42 is also supported by the increased size of the ready releasable pool (RRPsyn) and by the enhanced percentage of paired pulse depression (PPD). Interestingly, the RyRs inhibitor dantrolene prevents the increase of PPD induced by Abeta42 oligomers. In conclusion, Abeta42 up-regulates NMDA synaptic responses with a mechanism involving RyRs that occurs during the early stages of Alzheimer's disease (AD) onset. This suggests that new selective modulators of RyRs may be useful for designing effective therapies to treat AD patients.
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Affiliation(s)
| | | | - Pol Buxeda
- Department of Drug Science and Technology, Torino University, Italy
| | - Giulia Tomagra
- Department of Drug Science and Technology, Torino University, Italy
| | - Maurizio Giustetto
- Department of Neurosciences / National Institute of Neuroscience, Torino University, Italy.,National Institute of Neuroscience-Italy, Turin, Italy
| | | | | | - Emilio Carbone
- Department of Drug Science and Technology, Torino University, Italy
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19
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Gonzalez-Rodriguez P, Zampese E, Surmeier DJ. Selective neuronal vulnerability in Parkinson's disease. PROGRESS IN BRAIN RESEARCH 2020; 252:61-89. [PMID: 32247375 DOI: 10.1016/bs.pbr.2020.02.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Parkinson's disease (PD) is the second most common neurodegenerative disease, disabling millions worldwide. Despite the imperative PD poses, at present, there is no cure or means of slowing progression. This gap is attributable to our incomplete understanding of the factors driving pathogenesis. Research over the past several decades suggests that both cell-autonomous and non-cell autonomous processes contribute to the neuronal dysfunction underlying PD symptoms. The thesis of this review is that an intersection of these processes governs the pattern of pathology in PD. Studies of substantia nigra pars compacta (SNc) dopaminergic neurons, whose loss is responsible for the core motor symptoms of PD, suggest that they have a combination of traits-a long, highly branched axon, autonomous activity, and elevated mitochondrial oxidant stress-that predispose them to non-cell autonomous drivers of pathogenesis, like misfolded forms of alpha-synuclein (α-SYN) and inflammation. The literature surrounding these issues will be briefly summarized, and the translational implications of an intersectional hypothesis of PD pathogenesis discussed.
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Affiliation(s)
| | - Enrico Zampese
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - D James Surmeier
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States.
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20
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Nascimento F, Broadhead MJ, Tetringa E, Tsape E, Zagoraiou L, Miles GB. Synaptic mechanisms underlying modulation of locomotor-related motoneuron output by premotor cholinergic interneurons. eLife 2020; 9:e54170. [PMID: 32081133 PMCID: PMC7062467 DOI: 10.7554/elife.54170] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 02/20/2020] [Indexed: 01/15/2023] Open
Abstract
Spinal motor networks are formed by diverse populations of interneurons that set the strength and rhythmicity of behaviors such as locomotion. A small cluster of cholinergic interneurons, expressing the transcription factor Pitx2, modulates the intensity of muscle activation via 'C-bouton' inputs to motoneurons. However, the synaptic mechanisms underlying this neuromodulation remain unclear. Here, we confirm in mice that Pitx2+ interneurons are active during fictive locomotion and that their chemogenetic inhibition reduces the amplitude of motor output. Furthermore, after genetic ablation of cholinergic Pitx2+ interneurons, M2 receptor-dependent regulation of the intensity of locomotor output is lost. Conversely, chemogenetic stimulation of Pitx2+ interneurons leads to activation of M2 receptors on motoneurons, regulation of Kv2.1 channels and greater motoneuron output due to an increase in the inter-spike afterhyperpolarization and a reduction in spike half-width. Our findings elucidate synaptic mechanisms by which cholinergic spinal interneurons modulate the final common pathway for motor output.
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Affiliation(s)
- Filipe Nascimento
- School of Psychology and Neuroscience, University of St AndrewsSt AndrewsUnited Kingdom
| | | | - Efstathia Tetringa
- Center of Basic Research, Biomedical Research Foundation of the Academy of AthensAthensGreece
| | - Eirini Tsape
- Center of Basic Research, Biomedical Research Foundation of the Academy of AthensAthensGreece
| | - Laskaro Zagoraiou
- Center of Basic Research, Biomedical Research Foundation of the Academy of AthensAthensGreece
| | - Gareth Brian Miles
- School of Psychology and Neuroscience, University of St AndrewsSt AndrewsUnited Kingdom
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21
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Simons C, Benkert J, Deuter N, Poetschke C, Pongs O, Schneider T, Duda J, Liss B. NCS-1 Deficiency Affects mRNA Levels of Genes Involved in Regulation of ATP Synthesis and Mitochondrial Stress in Highly Vulnerable Substantia nigra Dopaminergic Neurons. Front Mol Neurosci 2019; 12:252. [PMID: 31827421 PMCID: PMC6890851 DOI: 10.3389/fnmol.2019.00252] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 09/27/2019] [Indexed: 12/20/2022] Open
Abstract
Neuronal Ca2+ sensor proteins (NCS) transduce changes in Ca2+ homeostasis into altered signaling and neuronal function. NCS-1 activity has emerged as important for neuronal viability and pathophysiology. The progressive degeneration of dopaminergic (DA) neurons, particularly within the Substantia nigra (SN), is the hallmark of Parkinson's disease (PD), causing its motor symptoms. The activity-related Ca2+ homeostasis of SN DA neurons, mitochondrial dysfunction, and metabolic stress promote neurodegeneration and PD. In contrast, NCS-1 in general has neuroprotective effects. The underlying mechanisms are unclear. We analyzed transcriptional changes in SN DA neurons upon NCS-1 loss by combining UV-laser microdissection and RT-qPCR-approaches to compare expression levels of a panel of PD and/or Ca2+-stress related genes from wildtype and NCS-1 KO mice. In NCS-1 KO, we detected significantly lower mRNA levels of mitochondrially coded ND1, a subunit of the respiratory chain, and of the neuron-specific enolase ENO2, a glycolytic enzyme. We also detected lower levels of the mitochondrial uncoupling proteins UCP4 and UCP5, the PARK7 gene product DJ-1, and the voltage-gated Ca2+ channel Cav2.3 in SN DA neurons from NCS-1 KO. Transcripts of other analyzed uncoupling proteins (UCPs), mitochondrial Ca2+ transporters, PARK genes, and ion channels were not altered. As Cav channels are linked to regulation of gene expression, metabolic stress and degeneration of SN DA neurons in PD, we analyzed Cav2.3 KO mice, to address if the transcriptional changes in NCS-1 KO were also present in Cav.2.3 KO, and thus probably correlated with lower Cav2.3 transcripts. However, in SN DA neurons from Cav2.3 KO mice, ND1 mRNA as well as genomic DNA levels were elevated, while ENO2, UCP4, UCP5, and DJ-1 transcript levels were not altered. In conclusion, our data indicate a possible novel function of NCS-1 in regulating gene transcription or stabilization of mRNAs in SN DA neurons. Although we do not provide functional data, our findings at the transcript level could point to impaired ATP production (lower ND1 and ENO2) and elevated metabolic stress (lower UCP4, UCP5, and DJ-1 levels) in SN DA neurons from NCS-1 KO mice. We speculate that NCS-1 is involved in stimulating ATP synthesis, while at the same time controlling mitochondrial metabolic stress, and in this way could protect SN DA neurons from degeneration.
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Affiliation(s)
- Carsten Simons
- Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | - Julia Benkert
- Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | - Nora Deuter
- Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | | | - Olaf Pongs
- Institute of Physiology, Center for Integrative Physiology and Molecular Medicine, University of the Saarland, Homburg, Germany
| | - Toni Schneider
- Institute of Neurophysiology, University of Cologne, Cologne, Germany
| | - Johanna Duda
- Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | - Birgit Liss
- Institute of Applied Physiology, University of Ulm, Ulm, Germany.,New College, University of Oxford, Oxford, United Kingdom
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22
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Benkert J, Hess S, Roy S, Beccano-Kelly D, Wiederspohn N, Duda J, Simons C, Patil K, Gaifullina A, Mannal N, Dragicevic E, Spaich D, Müller S, Nemeth J, Hollmann H, Deuter N, Mousba Y, Kubisch C, Poetschke C, Striessnig J, Pongs O, Schneider T, Wade-Martins R, Patel S, Parlato R, Frank T, Kloppenburg P, Liss B. Cav2.3 channels contribute to dopaminergic neuron loss in a model of Parkinson's disease. Nat Commun 2019; 10:5094. [PMID: 31704946 PMCID: PMC6841684 DOI: 10.1038/s41467-019-12834-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 09/27/2019] [Indexed: 12/21/2022] Open
Abstract
Degeneration of dopaminergic neurons in the substantia nigra causes the motor symptoms of Parkinson's disease. The mechanisms underlying this age-dependent and region-selective neurodegeneration remain unclear. Here we identify Cav2.3 channels as regulators of nigral neuronal viability. Cav2.3 transcripts were more abundant than other voltage-gated Ca2+ channels in mouse nigral neurons and upregulated during aging. Plasmalemmal Cav2.3 protein was higher than in dopaminergic neurons of the ventral tegmental area, which do not degenerate in Parkinson's disease. Cav2.3 knockout reduced activity-associated nigral somatic Ca2+ signals and Ca2+-dependent after-hyperpolarizations, and afforded full protection from degeneration in vivo in a neurotoxin Parkinson's mouse model. Cav2.3 deficiency upregulated transcripts for NCS-1, a Ca2+-binding protein implicated in neuroprotection. Conversely, NCS-1 knockout exacerbated nigral neurodegeneration and downregulated Cav2.3. Moreover, NCS-1 levels were reduced in a human iPSC-model of familial Parkinson's. Thus, Cav2.3 and NCS-1 may constitute potential therapeutic targets for combatting Ca2+-dependent neurodegeneration in Parkinson's disease.
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Affiliation(s)
- Julia Benkert
- Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | - Simon Hess
- Institute for Zoology, Biocenter, CECAD, University of Cologne, Cologne, Germany
| | - Shoumik Roy
- Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | - Dayne Beccano-Kelly
- Oxford Parkinson's Disease Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | | | - Johanna Duda
- Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | - Carsten Simons
- Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | - Komal Patil
- Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | | | - Nadja Mannal
- Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | - Elena Dragicevic
- Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | - Desirée Spaich
- Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | - Sonja Müller
- Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | - Julia Nemeth
- Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | - Helene Hollmann
- Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | - Nora Deuter
- Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | - Yassine Mousba
- Oxford Parkinson's Disease Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Christian Kubisch
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | - Joerg Striessnig
- Department of Pharmacology and Toxicology, Institute of Pharmacy, Center for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria
| | - Olaf Pongs
- Institute of Physiology, CIPMM, University of the Saarland, Homburg, Germany
| | - Toni Schneider
- Institute for Neurophysiology, University of Cologne, Cologne, Germany
| | - Richard Wade-Martins
- Oxford Parkinson's Disease Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Sandip Patel
- Department of Cell and Developmental Biology, UCL, London, UK
| | - Rosanna Parlato
- Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | - Tobias Frank
- Department of Neurology, University Medicine Göttingen, Göttingen, Germany
| | - Peter Kloppenburg
- Institute for Zoology, Biocenter, CECAD, University of Cologne, Cologne, Germany
| | - Birgit Liss
- Institute of Applied Physiology, University of Ulm, Ulm, Germany.
- New College, University of Oxford, Oxford, UK.
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23
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Ho SY, Chien YH, Tsai LK, Muramatsu SI, Hwu WL, Liou HH, Lee NC. Electrical Abnormalities in Dopaminergic Neurons of the Substantia Nigra in Mice With an Aromatic L-Amino Acid Decarboxylase Deficiency. Front Cell Neurosci 2019; 13:9. [PMID: 30766478 PMCID: PMC6365702 DOI: 10.3389/fncel.2019.00009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 01/10/2019] [Indexed: 12/25/2022] Open
Abstract
Aromatic L-acid decarboxylase (AADC) deficiency causes severe motor disturbances in affected children. A putamen-targeted gene therapy improves the motor function of patients. The present study investigated the electrical properties of dopaminergic (DA) neurons in the substantia nigra compacta (SNc) of mice with an AADC deficiency (DdcKI). The basal firing of DA neurons, which determines DA release in the putamen, was abnormal in the DdcKI mice, including a low frequency and irregular firing pattern, because of a decrease in the after-hyperpolarization (AHP) amplitude of action potentials (APs). The frequency of spontaneous excitatory postsynaptic currents (sEPSCs) increased and that of spontaneous inhibitory PSCs (sIPSCs) decreased in the SNc DA neurons from the DdcKI mice, suggesting an elevation in glutamatergic excitatory stimuli and a reduction in GABAergic inhibitory stimuli, respectively. Altered expression patterns of genes encoding receptors and channels were also observed in the DdcKI mice. Administration of a widespread neuron-specific gene therapy to the brains of the DdcKI mice partially corrected these electric abnormalities. The overexcitability of SNc DA neurons in the presence of generalized dopamine deficiency likely underlies the occurrence of motor disturbances.
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Affiliation(s)
- Shih-Yin Ho
- Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan.,Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yin-Hsiu Chien
- Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan.,Department of Pediatrics, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan
| | - Li-Kai Tsai
- Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan
| | - Shin-Ichi Muramatsu
- Division of Neurology, Department of Medicine, Jichi Medical University, Tochigi, Japan.,Center for Gene & Cell Therapy, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Wuh-Liang Hwu
- Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan.,Department of Pediatrics, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan
| | - Horng-Huei Liou
- Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan.,Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan.,Department of Neurology, National Taiwan University Hospital Yunlin Branch, Douliu, Taiwan
| | - Ni-Chung Lee
- Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan.,Department of Pediatrics, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan
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24
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Liss B, Striessnig J. The Potential of L-Type Calcium Channels as a Drug Target for Neuroprotective Therapy in Parkinson's Disease. Annu Rev Pharmacol Toxicol 2019; 59:263-289. [PMID: 30625283 DOI: 10.1146/annurev-pharmtox-010818-021214] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The motor symptoms of Parkinson's disease (PD) mainly arise from degeneration of dopamine neurons within the substantia nigra. As no disease-modifying PD therapies are available, and side effects limit long-term benefits of current symptomatic therapies, novel treatment approaches are needed. The ongoing phase III clinical study STEADY-PD is investigating the potential of the dihydropyridine isradipine, an L-type Ca2+ channel (LTCC) blocker, for neuroprotective PD therapy. Here we review the clinical and preclinical rationale for this trial and discuss potential reasons for the ambiguous outcomes of in vivo animal model studies that address PD-protective dihydropyridine effects. We summarize current views about the roles of Cav1.2 and Cav1.3 LTCC isoforms for substantia nigra neuron function, and their high vulnerability to degenerative stressors, and for PD pathophysiology. We discuss different dihydropyridine sensitivities of LTCC isoforms in view of their potential as drug targets for PD neuroprotection, and we conclude by considering how these aspects could guide further drug development.
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Affiliation(s)
- Birgit Liss
- Institut für Angewandte Physiologie, Universität Ulm, 89081 Ulm, Germany;
| | - Jörg Striessnig
- Abteilung Pharmakologie und Toxikologie, Institut für Pharmazie, and Center for Molecular Biosciences Innsbruck, Universität Innsbruck, A-6020 Innsbruck, Austria;
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25
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Teplov IY, Tuleukhanov ST, Zinchenko VP. Regulation of Action Potential Frequency and Amplitude by T-type Ca2+ Channel During Spontaneous Synchronous Activity of Hippocampal Neurons. Biophysics (Nagoya-shi) 2018. [DOI: 10.1134/s0006350918040206] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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