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Enck JR, Olson EC. Calcium Signaling during Cortical Apical Dendrite Initiation: A Role for Cajal-Retzius Neurons. Int J Mol Sci 2023; 24:12965. [PMID: 37629145 PMCID: PMC10455361 DOI: 10.3390/ijms241612965] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 08/15/2023] [Accepted: 08/17/2023] [Indexed: 08/27/2023] Open
Abstract
The apical dendrite of a cortical projection neuron (CPN) is generated from the leading process of the migrating neuron as the neuron completes migration. This transformation occurs in the cortical marginal zone (MZ), a layer that contains the Cajal-Retzius neurons and their axonal projections. Cajal-Retzius neurons (CRNs) are well known for their critical role in secreting Reelin, a glycoprotein that controls dendritogenesis and cell positioning in many regions of the developing brain. In this study, we examine the possibility that CRNs in the MZ may provide additional signals to arriving CPNs, that may promote the maturation of CPNs and thus shape the development of the cortex. We use whole embryonic hemisphere explants and multiphoton microscopy to confirm that CRNs display intracellular calcium transients of <1-min duration and high amplitude during early corticogenesis. In contrast, developing CPNs do not show high-amplitude calcium transients, but instead show a steady increase in intracellular calcium that begins at the time of dendritic initiation, when the leading process of the migrating CPN is encountering the MZ. The possible existence of CRN to CPN communication was revealed by the application of veratridine, a sodium channel activator, which has been shown to preferentially stimulate more mature cells in the MZ at an early developmental time. Surprisingly, veratridine application also triggers large calcium transients in CPNs, which can be partially blocked by a cocktail of antagonists that block glutamate and glycine receptor activation. These findings outline a model in which CRN spontaneous activity triggers the release of glutamate and glycine, neurotransmitters that can trigger intracellular calcium elevations in CPNs. These elevations begin as CPNs initiate dendritogenesis and continue as waves in the post-migratory cells. Moreover, we show that the pharmacological blockade of glutamatergic signaling disrupts migration, while forced expression of a bacterial voltage-gated calcium channel (CavMr) in the migrating neurons promotes dendritic growth and migration arrest. The identification of CRN to CPN signaling during early development provides insight into the observation that many autism-linked genes encode synaptic proteins that, paradoxically, are expressed in the developing cortex well before the appearance of synapses and the establishment of functional circuits.
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Affiliation(s)
| | - Eric C. Olson
- Department of Neuroscience and Physiology, State University of New York Upstate Medical University, 505 Irving Ave., Syracuse, NY 13210, USA;
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2
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Pharmacological Dissection of the Crosstalk between Na V and Ca V Channels in GH3b6 Cells. Int J Mol Sci 2022; 23:ijms23020827. [PMID: 35055012 PMCID: PMC8775721 DOI: 10.3390/ijms23020827] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 01/07/2022] [Accepted: 01/09/2022] [Indexed: 02/01/2023] Open
Abstract
Thanks to the crosstalk between Na+ and Ca2+ channels, Na+ and Ca2+ homeostasis interplay in so-called excitable cells enables the generation of action potential in response to electrical stimulation. Here, we investigated the impact of persistent activation of voltage-gated Na+ (NaV) channels by neurotoxins, such as veratridine (VTD), on intracellular Ca2+ concentration ([Ca2+]i) in a model of excitable cells, the rat pituitary GH3b6 cells, in order to identify the molecular actors involved in Na+-Ca2+ homeostasis crosstalk. By combining RT-qPCR, immunoblotting, immunocytochemistry, and patch-clamp techniques, we showed that GH3b6 cells predominantly express the NaV1.3 channel subtype, which likely endorses their voltage-activated Na+ currents. Notably, these Na+ currents were blocked by ICA-121431 and activated by the β-scorpion toxin Tf2, two selective NaV1.3 channel ligands. Using Fura-2, we showed that VTD induced a [Ca2+]i increase. This effect was suppressed by the selective NaV channel blocker tetrodotoxin, as well by the selective L-type CaV channel (LTCC) blocker nifedipine. We also evidenced that crobenetine, a NaV channel blocker, abolished VTD-induced [Ca2+]i elevation, while it had no effects on LTCC. Altogether, our findings highlight a crosstalk between NaV and LTCC in GH3b6 cells, providing a new insight into the mode of action of neurotoxins.
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3
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Parker PD, Suryavanshi P, Melone M, Sawant-Pokam PA, Reinhart KM, Kaufmann D, Theriot JJ, Pugliese A, Conti F, Shuttleworth CW, Pietrobon D, Brennan KC. Non-canonical glutamate signaling in a genetic model of migraine with aura. Neuron 2021; 109:611-628.e8. [PMID: 33321071 PMCID: PMC7889497 DOI: 10.1016/j.neuron.2020.11.018] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 10/09/2020] [Accepted: 11/17/2020] [Indexed: 12/13/2022]
Abstract
Migraine with aura is a common but poorly understood sensory circuit disorder. Monogenic models allow an opportunity to investigate its mechanisms, including spreading depolarization (SD), the phenomenon underlying migraine aura. Using fluorescent glutamate imaging, we show that awake mice carrying a familial hemiplegic migraine type 2 (FHM2) mutation have slower clearance during sensory processing, as well as previously undescribed spontaneous "plumes" of glutamate. Glutamatergic plumes overlapped anatomically with a reduced density of GLT-1a-positive astrocyte processes and were mimicked in wild-type animals by inhibiting glutamate clearance. Plume pharmacology and plume-like neural Ca2+ events were consistent with action-potential-independent spontaneous glutamate release, suggesting plumes are a consequence of inefficient clearance following synaptic release. Importantly, a rise in basal glutamate and plume frequency predicted the onset of SD in both FHM2 and wild-type mice, providing a novel mechanism in migraine with aura and, by extension, the other neurological disorders where SD occurs.
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Affiliation(s)
- Patrick D Parker
- Department of Neurology, University of Utah School of Medicine, Salt Lake City, UT 84108, USA; Interdepartmental Program in Neuroscience, University of Utah School of Medicine, Salt Lake City, UT 84108, USA
| | - Pratyush Suryavanshi
- Department of Neurology, University of Utah School of Medicine, Salt Lake City, UT 84108, USA; Interdepartmental Program in Neuroscience, University of Utah School of Medicine, Salt Lake City, UT 84108, USA
| | - Marcello Melone
- Section of Neuroscience and Cell Biology, Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona 60020, Italy; Center for Neurobiology of Aging, IRCCS INRCA, Ancona 60020, Italy
| | - Punam A Sawant-Pokam
- Department of Neurology, University of Utah School of Medicine, Salt Lake City, UT 84108, USA
| | - Katelyn M Reinhart
- Department of Neurology, University of Utah School of Medicine, Salt Lake City, UT 84108, USA; Department of Neurosciences, University of New Mexico School of Medicine, Albuquerque, NM 87106, USA
| | - Dan Kaufmann
- Department of Neurology, University of Utah School of Medicine, Salt Lake City, UT 84108, USA
| | - Jeremy J Theriot
- Department of Neurology, University of Utah School of Medicine, Salt Lake City, UT 84108, USA
| | - Arianna Pugliese
- Section of Neuroscience and Cell Biology, Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona 60020, Italy
| | - Fiorenzo Conti
- Section of Neuroscience and Cell Biology, Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona 60020, Italy; Center for Neurobiology of Aging, IRCCS INRCA, Ancona 60020, Italy; Foundation for Molecular Medicine, Università Politecnica delle Marche, Ancona 60020, Italy
| | - C William Shuttleworth
- Department of Neurosciences, University of New Mexico School of Medicine, Albuquerque, NM 87106, USA
| | - Daniela Pietrobon
- Department of Biomedical Sciences and Padova Neuroscience Center (PNC), University of Padova, 35131 Padova, Italy; CNR Institute of Neuroscience, 35131 Padova, Italy.
| | - K C Brennan
- Department of Neurology, University of Utah School of Medicine, Salt Lake City, UT 84108, USA.
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4
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Pérez-Hernández M, Leo-Macias A, Keegan S, Jouni M, Kim JC, Agullo-Pascual E, Vermij S, Zhang M, Liang FX, Burridge P, Fenyö D, Rothenberg E, Delmar M. Structural and Functional Characterization of a Na v1.5-Mitochondrial Couplon. Circ Res 2021; 128:419-432. [PMID: 33342222 PMCID: PMC7864872 DOI: 10.1161/circresaha.120.318239] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
RATIONALE The cardiac sodium channel NaV1.5 has a fundamental role in excitability and conduction. Previous studies have shown that sodium channels cluster together in specific cellular subdomains. Their association with intracellular organelles in defined regions of the myocytes, and the functional consequences of that association, remain to be defined. OBJECTIVE To characterize a subcellular domain formed by sodium channel clusters in the crest region of the myocytes and the subjacent subsarcolemmal mitochondria. METHODS AND RESULTS Through a combination of imaging approaches including super-resolution microscopy and electron microscopy we identified, in adult cardiac myocytes, a NaV1.5 subpopulation in close proximity to subjacent subsarcolemmal mitochondria; we further found that subjacent subsarcolemmal mitochondria preferentially host the mitochondrial NCLX (Na+/Ca2+ exchanger). This anatomic proximity led us to investigate functional changes in mitochondria resulting from sodium channel activity. Upon TTX (tetrodotoxin) exposure, mitochondria near NaV1.5 channels accumulated more Ca2+ and showed increased reactive oxygen species production when compared with interfibrillar mitochondria. Finally, crosstalk between NaV1.5 channels and mitochondria was analyzed at a transcriptional level. We found that SCN5A (encoding NaV1.5) and SLC8B1 (which encode NaV1.5 and NCLX, respectively) are negatively correlated both in a human transcriptome data set (Genotype-Tissue Expression) and in human-induced pluripotent stem cell-derived cardiac myocytes deficient in SCN5A. CONCLUSIONS We describe an anatomic hub (a couplon) formed by sodium channel clusters and subjacent subsarcolemmal mitochondria. Preferential localization of NCLX to this domain allows for functional coupling where the extrusion of Ca2+ from the mitochondria is powered, at least in part, by the entry of sodium through NaV1.5 channels. These results provide a novel entry-point into a mechanistic understanding of the intersection between electrical and structural functions of the heart.
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Affiliation(s)
| | - Alejandra Leo-Macias
- Leon H Charney Division of Cardiology NYU Grossman School of Medicine. New York, NY
| | - Sarah Keegan
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology. NYU Grossman School of Medicine. New York, NY
| | - Mariam Jouni
- Department of Pharmacology, Northwestern University Feinberg School of Medicine. Chicago, IL
| | - Joon-Chul Kim
- Leon H Charney Division of Cardiology NYU Grossman School of Medicine. New York, NY
| | | | - Sarah Vermij
- Leon H Charney Division of Cardiology NYU Grossman School of Medicine. New York, NY
| | - Mingliang Zhang
- Leon H Charney Division of Cardiology NYU Grossman School of Medicine. New York, NY
| | - Feng-Xia Liang
- Microscopy laboratory, Division of Advanced Research Technologies. NYU Grossman School of Medicine. New York, NY
| | - Paul Burridge
- Department of Pharmacology, Northwestern University Feinberg School of Medicine. Chicago, IL
| | - David Fenyö
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology. NYU Grossman School of Medicine. New York, NY
| | - Eli Rothenberg
- Institute for Systems Genetics and Department of Biochemistry and Molecular Pharmacology. NYU Grossman School of Medicine. New York, NY
| | - Mario Delmar
- Leon H Charney Division of Cardiology NYU Grossman School of Medicine. New York, NY
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5
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Calovi S, Mut-Arbona P, Tod P, Iring A, Nicke A, Mato S, Vizi ES, Tønnesen J, Sperlagh B. P2X7 Receptor-Dependent Layer-Specific Changes in Neuron-Microglia Reactivity in the Prefrontal Cortex of a Phencyclidine Induced Mouse Model of Schizophrenia. Front Mol Neurosci 2020; 13:566251. [PMID: 33262687 PMCID: PMC7686553 DOI: 10.3389/fnmol.2020.566251] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 09/30/2020] [Indexed: 12/22/2022] Open
Abstract
Background: It has been consistently reported that the deficiency of the adenosine triphosphate (ATP) sensitive purinergic receptor P2X7 (P2X7R) ameliorates symptoms in animal models of brain diseases. Objective: This study aimed to investigate the role of P2X7R in rodent models of acute and subchronic schizophrenia based on phencyclidine (PCP) delivery in animals lacking or overexpressing P2X7R, and to identify the underlying mechanisms involved. Methods: The psychotomimetic effects of acute i.p. PCP administration in C57Bl/6J wild-type, P2X7R knockout (P2rx7−/−) and overexpressing (P2X7-EGFP) young adult mice were quantified. The medial prefrontal cortex (mPFC) of P2rx7−/− and heterozygous P2X7-EGFP acutely treated animals was characterized through immunohistochemical staining. The prefrontal cortices of young adult P2rx7−/− and P2rx7tg/+ mice were examined with tritiated dopamine release experiments and the functional properties of the mPFC pyramidal neurons in layer V from P2rx7−/− mice were assessed by patch-clamp recordings. P2rx7−/− animals were subjected to a 7 days subchronic systemic PCP treatment. The animals working memory performance and PFC cytokine levels were assessed. Results: Our data strengthen the hypothesis that P2X7R modulates schizophrenia-like positive and cognitive symptoms in NMDA receptor antagonist models in a receptor expression level-dependent manner. P2X7R expression leads to higher medial PFC susceptibility to PCP-induced circuit hyperactivity. The mPFC of P2X7R knockout animals displayed distinct alterations in the neuronal activation pattern, microglial organization, specifically around hyperactive neurons, and were associated with lower intrinsic excitability of mPFC neurons. Conclusions: P2X7R expression exacerbated PCP-related effects in C57Bl/6J mice. Our findings suggest a pleiotropic role of P2X7R in the mPFC, consistent with the observed behavioral phenotype, regulating basal dopamine concentration, layer-specific neuronal activation, intrinsic excitability of neurons in the mPFC, and the interaction of microglia with hyperactive neurons. Direct measurements of P2X7R activity concerning microglial ramifications and dynamics could help to further elucidate the molecular mechanisms involved.
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Affiliation(s)
- Stefano Calovi
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, Budapest, Hungary.,János Szentágothai Doctoral School, Semmelweis University, Budapest, Hungary
| | - Paula Mut-Arbona
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, Budapest, Hungary.,János Szentágothai Doctoral School, Semmelweis University, Budapest, Hungary
| | - Pál Tod
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, Budapest, Hungary
| | - András Iring
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, Budapest, Hungary
| | - Annette Nicke
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, LMU Munich, Munich, Germany
| | - Susana Mato
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Department of Neuroscience, University of the Basque Country (UPV/EHU), Leioa, Spain.,Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Biocruces Bizkaia, Barakaldo, Spain
| | - E Sylvester Vizi
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, Budapest, Hungary
| | - Jan Tønnesen
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Department of Neuroscience, University of the Basque Country (UPV/EHU), Leioa, Spain
| | - Beata Sperlagh
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, Budapest, Hungary
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6
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Bragança B, Nogueira-Marques S, Ferreirinha F, Fontes-Sousa AP, Correia-de-Sá P. The Ionotropic P2X4 Receptor has Unique Properties in the Heart by Mediating the Negative Chronotropic Effect of ATP While Increasing the Ventricular Inotropy. Front Pharmacol 2019; 10:1103. [PMID: 31611793 PMCID: PMC6769074 DOI: 10.3389/fphar.2019.01103] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 08/28/2019] [Indexed: 01/09/2023] Open
Abstract
Background: Mounting evidence indicate that reducing the sinoatrial node (SAN) activity may be a useful therapeutic strategy to control of heart failure. Purines, like ATP and its metabolite adenosine, consistently reduce the SAN spontaneous activity leading to negative cardiac chronotropy, with variable effects on the force of myocardial contraction (inotropy). Apart from adenosine A1 receptors, the human SAN expresses high levels of ATP-sensitive ionotropic P2X4 receptors (P2X4R), yet their cardiac role is unexplored. Methods: Here, we investigated the activity of P2 purinoceptors on isolated spontaneously beating atria (chronotropy) and on 2 Hz-paced right ventricular (RV, inotropy) strips from Wistar rats. Results: ATP (pEC 50 = 4.05) and its stable analogue ATPγS (pEC 50 = 4.69) concentration-dependently reduced atrial chronotropy. Inhibition of ATP breakdown into adenosine by NTPDases with POM-1 failed to modify ATP-induced negative chronotropy. The effect of ATP on atrial rate was attenuated by a broad-spectrum P2 antagonist, PPADS, as well as by 5-BDBD, which selectively blocks the P2X4R subtype; however, no effect was observed upon blocking the A1 receptor with DPCPX. The P2X4R positive allosteric modulator, ivermectin, increased the negative chronotropic response of ATP. Likewise, CTP, a P2X agonist that does not generate adenosine, replicated the P2X4R-mediated negative chronotropism of ATP. Inhibition of the Na+/Ca2+ exchanger (NCX) with KB-R7943 and ORM-10103, but not blockage of the HCN channel with ZD7288, mimicked the effect of the P2X4R blocker, 5-BDBD. In paced RV strips, ATP caused a mild negative inotropic effect, which magnitude was 2 to 3-fold increased by 5-BDBD and KB-R7943. Immunofluorescence confocal microscopy studies confirm that cardiomyocytes of the rat SAN and RV co-express P2X4R and NCX1 proteins. Conclusions: Data suggest that activation of ATP-sensitive P2X4R slows down heart rate by reducing the SAN activity while increasing the magnitude of ventricular contractions. The mechanism underlying the dual effect of ATP in the heart may involve inhibition of intracellular Ca2+-extrusion by bolstering NCX function in the reverse mode. Thus, targeting the P2X4R activation may create novel well-tolerated heart-rate lowering drugs with potential benefits in patients with deteriorated ventricular function.
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Affiliation(s)
- Bruno Bragança
- Laboratório de Farmacologia e Neurobiologia, Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal.,Hospital Pedro Hispano, ULS Matosinhos, Matosinhos, Portugal
| | - Sílvia Nogueira-Marques
- Laboratório de Farmacologia e Neurobiologia, Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Fátima Ferreirinha
- Laboratório de Farmacologia e Neurobiologia, Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Ana Patrícia Fontes-Sousa
- Laboratório de Farmacologia e Neurobiologia, Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Paulo Correia-de-Sá
- Laboratório de Farmacologia e Neurobiologia, Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
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7
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Shan Z, Cai S, Yu J, Zhang Z, Vallecillo TGM, Serafini MJ, Thomas AM, Pham NYN, Bellampalli SS, Moutal A, Zhou Y, Xu GB, Xu YM, Luo S, Patek M, Streicher JM, Gunatilaka AAL, Khanna R. Reversal of Peripheral Neuropathic Pain by the Small-Molecule Natural Product Physalin F via Block of CaV2.3 (R-Type) and CaV2.2 (N-Type) Voltage-Gated Calcium Channels. ACS Chem Neurosci 2019; 10:2939-2955. [PMID: 30946560 DOI: 10.1021/acschemneuro.9b00166] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
No universally efficacious therapy exists for chronic pain, a disease affecting one-fifth of the global population. An overreliance on the prescription of opioids for chronic pain despite their poor ability to improve function has led to a national opioid crisis. In 2018, the NIH launched a Helping to End Addiction Long-term plan to spur discovery and validation of novel targets and mechanisms to develop alternative nonaddictive treatment options. Phytochemicals with medicinal properties have long been used for various treatments worldwide. The natural product physalin F, isolated from the Physalis acutifolia (family: Solanaceae) herb, demonstrated antinociceptive effects in models of inflammatory pain, consistent with earlier reports of its anti-inflammatory and immunomodulatory activities. However, the target of action of physalin F remained unknown. Here, using whole-cell and slice electrophysiology, competition binding assays, and experimental models of neuropathic pain, we uncovered a molecular target for physalin F's antinociceptive actions. We found that physalin F (i) blocks CaV2.3 (R-type) and CaV2.2 (N-type) voltage-gated calcium channels in dorsal root ganglion (DRG) neurons, (ii) does not affect CaV3 (T-type) voltage-gated calcium channels or voltage-gated sodium or potassium channels, (iii) does not bind G-protein coupled opioid receptors, (iv) inhibits the frequency of spontaneous excitatory postsynaptic currents (EPSCs) in spinal cord slices, and (v) reverses tactile hypersensitivity in models of paclitaxel-induced peripheral neuropathy and spinal nerve ligation. Identifying CaV2.2 as a molecular target of physalin F may spur its use as a tool for mechanistic studies and position it as a structural template for future synthetic compounds.
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Affiliation(s)
- Zhiming Shan
- Department of Anesthesiology, Shenzhen People’s Hospital & Second Clinical Medical College of Jinan University, Shenzhen 518020, P.R. China
- Department of Anesthesiology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, P.R. China
| | | | - Jie Yu
- College of Basic Medical Science, Zhejiang Chinese Medical University, Hangzhou 310058, P.R. China
| | - Zhongjun Zhang
- Department of Anesthesiology, Shenzhen People’s Hospital & Second Clinical Medical College of Jinan University, Shenzhen 518020, P.R. China
| | | | | | | | | | | | | | - Yuan Zhou
- The First Hospital of Jilin University, 71 Xinmin Street, Changchun 130021, P. R. China
- BrightRock Path Consulting, LLC, Tucson 85721, Arizona, United States
| | | | | | | | - Marcel Patek
- BrightRock Path Consulting, LLC, Tucson 85721, Arizona, United States
| | | | | | - Rajesh Khanna
- The Center for Innovation in Brain Sciences, The University of Arizona Health Sciences, Tucson, Arizona 85724, United States
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8
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Walters DC, Arning E, Bottiglieri T, Jansen EEW, Salomons GS, Brown MN, Schmidt MA, Ainslie GR, Roullet JB, Gibson KM. Metabolomic analyses of vigabatrin (VGB)-treated mice: GABA-transaminase inhibition significantly alters amino acid profiles in murine neural and non-neural tissues. Neurochem Int 2019; 125:151-162. [PMID: 30822440 DOI: 10.1016/j.neuint.2019.02.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 02/19/2019] [Accepted: 02/20/2019] [Indexed: 11/18/2022]
Abstract
The anticonvulsant vigabatrin (VGB; SabrilR) irreversibly inhibits GABA transaminase to increase neural GABA, yet its mechanism of retinal toxicity remains unclear. VGB is suggested to alter several amino acids, including homocarnosine, β-alanine, ornithine, glycine, taurine, and 2-aminoadipic acid (AADA), the latter a homologue of glutamic acid. Here, we evaluate the effect of VGB on amino acid concentrations in mice, employing a continuous VGB infusion (subcutaneously implanted osmotic minipumps), dose-escalation paradigm (35-140 mg/kg/d, 12 days), and amino acid quantitation in eye, visual and prefrontal cortex, total brain, liver and plasma. We hypothesized that continuous VGB dosing would reveal numerous hitherto undescribed amino acid disturbances. Consistent amino acid elevations across tissues included GABA, β-alanine, carnosine, ornithine and AADA, as well as neuroactive aspartic and glutamic acids, serine and glycine. Maximal increase of AADA in eye occurred at 35 mg/kg/d (41 ± 2 nmol/g (n = 21, vehicle) to 60 ± 8.5 (n = 8)), and at 70 mg/kg/d for brain (97 ± 6 (n = 21) to 145 ± 6 (n = 6)), visual cortex (128 ± 6 to 215 ± 19) and prefrontal cortex (124 ± 11 to 200 ± 13; mean ± SEM; p < 0.05), the first demonstration of tissue AADA accumulation with VGB in mammal. VGB effects on basic amino acids, including guanidino-species, suggested the capacity of VGB to alter urea cycle function and nitrogen disposal. The known toxicity of AADA in retinal glial cells highlights new avenues for assessing VGB retinal toxicity and other off-target effects.
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Affiliation(s)
- Dana C Walters
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, USA
| | - Erland Arning
- Baylor Scott & White Research Institute, Institute of Metabolic Disease, Dallas, TX, USA
| | - Teodoro Bottiglieri
- Baylor Scott & White Research Institute, Institute of Metabolic Disease, Dallas, TX, USA
| | - Erwin E W Jansen
- Metabolic Laboratory, Department of Clinical Chemistry, Amsterdam University Medical Center, the Netherlands
| | - Gajja S Salomons
- Metabolic Laboratory, Department of Clinical Chemistry, Amsterdam University Medical Center, the Netherlands
| | - Madalyn N Brown
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, USA
| | - Michelle A Schmidt
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, USA
| | - Garrett R Ainslie
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, USA
| | - Jean-Baptiste Roullet
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, USA
| | - K Michael Gibson
- Department of Pharmacotherapy, College of Pharmacy and Pharmaceutical Sciences, Washington State University, Spokane, WA, USA.
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9
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Lou J, Wu H, Wang L, Zhao L, Li X, Kang Y, Wen K, Yin Y. Taurine-magnesium coordination compound, a potential anti-arrhythmic complex, improves aconitine-induced arrhythmias through regulation of multiple ion channels. Toxicol Appl Pharmacol 2018; 356:182-190. [PMID: 30125596 DOI: 10.1016/j.taap.2018.08.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 08/03/2018] [Accepted: 08/14/2018] [Indexed: 12/14/2022]
Abstract
Taurine-magnesium coordination compound (TMCC) exhibits antiarrhythmic effects in cesium-chloride-and ouabain-induced arrhythmias; however, the mechanism underlying these effects on arrhythmia remains poorly understood. Here, we investigated the effects of TMCC on aconitine-induced arrhythmia in vivo and the electrophysiological effects of this compound in rat ventricular myocytes in vitro. Aconitine was used to induce arrhythmias in rats, and the dosages required to produce ventricular premature contraction (VPC), ventricular tachycardia (VT), ventricular fibrillation (VF), and cardiac arrest (CA) were recorded. Additionally, the sodium current (INa) and L-type calcium current (ICa,L) were analyzed in normal and aconitine-treated ventricular myocytes using whole-cell patch-clamp recording. In vivo, intravenous administration of TMCC produced marked antiarrhythmic effects, as indicated by the increased dose of aconitine required to induce VPC, VT, VF, and CA. Moreover, this effect was abolished by administration of sodium channel opener veratridine and calcium channel agonist Bay K8644. In vitro, TMCC inhibited aconitine-induced increases in INa and ICa,L. These results revealed that TMCC inhibited aconitine-induced arrhythmias through effects on INa and ICa,L.
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Affiliation(s)
- Jianshi Lou
- Department of Pharmacology, Tianjin Medical University, Tianjin, PR China
| | - Hong Wu
- Department of Pharmacology, Tianjin Medical University, Tianjin, PR China; Mudanjiang Medical University, Mudanjiang, PR China
| | - Lingfang Wang
- Institute of Translational Medicine, Nanchang University, Nanchang, PR China
| | - Lin Zhao
- International College, Tianjin Medical University, Tianjin, PR China
| | - Xin Li
- Department of Pharmacology, Tianjin Medical University, Tianjin, PR China
| | - Yi Kang
- Department of Pharmacology, Tianjin Medical University, Tianjin, PR China
| | - Ke Wen
- Department of Pharmacology, Tianjin Medical University, Tianjin, PR China
| | - Yongqiang Yin
- Department of Pharmacology, Tianjin Medical University, Tianjin, PR China.
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10
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Müller P, Draguhn A, Egorov AV. Persistent sodium current modulates axonal excitability in CA1 pyramidal neurons. J Neurochem 2018; 146:446-458. [PMID: 29863287 DOI: 10.1111/jnc.14479] [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: 01/14/2018] [Revised: 05/01/2018] [Accepted: 05/25/2018] [Indexed: 12/11/2022]
Abstract
Axonal excitability is an important determinant for the accuracy, direction, and velocity of neuronal signaling. The mechanisms underlying spike generation in the axonal initial segment and transmitter release from presynaptic terminals have been intensely studied and revealed a role for several specific ionic conductances, including the persistent sodium current (INaP ). Recent evidence indicates that action potentials can also be generated at remote locations along the axonal fiber, giving rise to ectopic action potentials during physiological states (e.g., fast network oscillations) or in pathological situations (e.g., following demyelination). Here, we investigated how ectopic axonal excitability of mouse hippocampal CA1 pyramidal neurons is regulated by INaP . Recordings of field potentials and intracellular voltage in brain slices revealed that electrically evoked antidromic spikes were readily suppressed by two different blockers of INaP , riluzole and phenytoin. The effect was mediated by a reduction of the probability of ectopic spike generation while latency was unaffected. Interestingly, the contribution of INaP to excitability was much more pronounced in axonal branches heading toward the entorhinal cortex compared with the opposite fiber direction toward fimbria. Thus, excitability of distal CA1 pyramidal cell axons is affected by persistent sodium currents in a direction-selective manner. This mechanism may be of importance for ectopic spike generation in oscillating network states as well as in pathological situations.
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Affiliation(s)
- Peter Müller
- Department of Neurophysiology, Institute of Physiology and Pathophysiology, Heidelberg University, Heidelberg, Germany
| | - Andreas Draguhn
- Department of Neurophysiology, Institute of Physiology and Pathophysiology, Heidelberg University, Heidelberg, Germany
| | - Alexei V Egorov
- Department of Neurophysiology, Institute of Physiology and Pathophysiology, Heidelberg University, Heidelberg, Germany
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11
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Rubio Ayala M, Syrovets T, Hafner S, Zablotskii V, Dejneka A, Simmet T. Spatiotemporal magnetic fields enhance cytosolic Ca 2+ levels and induce actin polymerization via activation of voltage-gated sodium channels in skeletal muscle cells. Biomaterials 2018; 163:174-184. [PMID: 29471128 DOI: 10.1016/j.biomaterials.2018.02.031] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 01/27/2018] [Accepted: 02/13/2018] [Indexed: 12/13/2022]
Abstract
Cellular function is modulated by the electric membrane potential controlling intracellular physiology and signal propagation from a motor neuron to a muscle fiber resulting in muscle contraction. Unlike electric fields, magnetic fields are not attenuated by biological materials and penetrate deep into the tissue. We used complex spatiotemporal magnetic fields (17-70 mT) to control intracellular signaling in skeletal muscle cells. By changing different parameters of the alternating magnetic field (amplitude, inversion time, rotation frequency), we induced transient depolarization of cellular membranes leading to i) Na+ influx through voltage-gated sodium channels (VGSC), ii) cytosolic calcium increase, and iii) VGSC- and ryanodine receptor-dependent increase of actin polymerization. The ion fluxes occurred only, when the field was applied and returned to baseline after the field was turned off. The 30-s-activation-cycle could be repeated without any loss of signal intensity. By contrast, static magnetic fields of the same strength exhibited no effect on myotube Ca2+ levels. Mathematical modeling suggested a role for the alternating magnetic field-induced eddy current, which mediates a local change in the membrane potential triggering the activation of VGSC. These findings might pave the way for the use of complex magnetic fields to improve function of skeletal muscles in myopathies.
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Affiliation(s)
- Mónica Rubio Ayala
- Institute of Pharmacology of Natural Products & Clinical Pharmacology, Ulm University, Ulm, 89081, Germany
| | - Tatiana Syrovets
- Institute of Pharmacology of Natural Products & Clinical Pharmacology, Ulm University, Ulm, 89081, Germany
| | - Susanne Hafner
- Institute of Pharmacology of Natural Products & Clinical Pharmacology, Ulm University, Ulm, 89081, Germany
| | - Vitalii Zablotskii
- Institute of Physics Academy of Sciences of the Czech Republic, Prague 8, Czech Republic
| | - Alexandr Dejneka
- Institute of Physics Academy of Sciences of the Czech Republic, Prague 8, Czech Republic
| | - Thomas Simmet
- Institute of Pharmacology of Natural Products & Clinical Pharmacology, Ulm University, Ulm, 89081, Germany.
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12
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Fu C, Hao J, Zeng M, Song Y, Jiang W, Zhang P, Luo A, Cao Z, Belardinelli L, Ma J. Modulation of late sodium current by Ca2+-calmodulin-dependent protein kinase II, protein kinase C and Ca2+during hypoxia in rabbit ventricular myocytes. Exp Physiol 2017; 102:818-834. [DOI: 10.1113/ep085990] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 04/13/2017] [Indexed: 01/05/2023]
Affiliation(s)
- Chen Fu
- Cardio-Electrophysiological Research Laboratory; Medical College of Wuhan University of Science and Technology; Wuhan China
- Department of Cardiovascular Medicine; Tianyou Hospital, affiliated to Wuhan University of Science and Technology; Wuhan China
| | - Jie Hao
- Cardio-Electrophysiological Research Laboratory; Medical College of Wuhan University of Science and Technology; Wuhan China
| | - Mengliu Zeng
- Cardio-Electrophysiological Research Laboratory; Medical College of Wuhan University of Science and Technology; Wuhan China
| | - Yejia Song
- Division of Cardiovascular Medicine; University of Florida College of Medicine; Gainesville FL USA
| | - Wanzhen Jiang
- Cardio-Electrophysiological Research Laboratory; Medical College of Wuhan University of Science and Technology; Wuhan China
| | - Peihua Zhang
- Cardio-Electrophysiological Research Laboratory; Medical College of Wuhan University of Science and Technology; Wuhan China
| | - Antao Luo
- Cardio-Electrophysiological Research Laboratory; Medical College of Wuhan University of Science and Technology; Wuhan China
| | - Zhenzhen Cao
- Cardio-Electrophysiological Research Laboratory; Medical College of Wuhan University of Science and Technology; Wuhan China
| | | | - Jihua Ma
- Cardio-Electrophysiological Research Laboratory; Medical College of Wuhan University of Science and Technology; Wuhan China
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13
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Rhana P, Trivelato RR, Beirão PSL, Cruz JS, Rodrigues ALP. Is there a role for voltage-gated Na+ channels in the aggressiveness of breast cancer? ACTA ACUST UNITED AC 2017; 50:e6011. [PMID: 28591378 PMCID: PMC5463531 DOI: 10.1590/1414-431x20176011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 04/11/2017] [Indexed: 12/19/2022]
Abstract
Breast cancer is the most common cancer among women and its metastatic potential is responsible for numerous deaths. Thus, the need to find new targets for improving treatment, and even finding the cure, becomes increasingly greater. Ion channels are known to participate in several physiological functions, such as muscle contraction, cell volume regulation, immune response and cell proliferation. In breast cancer, different types of ion channels have been associated with tumorigenesis. Recently, voltage-gated Na+ channels (VGSC) have been implicated in the processes that lead to increased tumor aggressiveness. To explain this relationship, different theories, associated with pH changes, gene expression and intracellular Ca2+, have been proposed in an attempt to better understand the role of these ion channels in breast cancer. However, these theories are having difficulty being accepted because most of the findings are contrary to the present scientific knowledge. Several studies have shown that VGSC are related to different types of cancer, making them a promising pharmacological target against this debilitating disease. Molecular biology and cell electrophysiology have been used to look for new forms of treatment aiming to reduce aggressiveness and the disease progress.
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Affiliation(s)
- P Rhana
- Laboratório de Câncer de Mama, Canais Iônicos e AMP Cíclico, Faculdade de Ciências Humanas, Sociais e da Saúde, Universidade FUMEC, Belo Horizonte, MG, Brasil.,Laboratório de Membranas Excitáveis e de Biologia Cardiovascular, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - R R Trivelato
- Laboratório de Câncer de Mama, Canais Iônicos e AMP Cíclico, Faculdade de Ciências Humanas, Sociais e da Saúde, Universidade FUMEC, Belo Horizonte, MG, Brasil
| | - P S L Beirão
- Laboratório de Membranas Excitáveis e de Biologia Cardiovascular, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - J S Cruz
- Laboratório de Membranas Excitáveis e de Biologia Cardiovascular, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - A L P Rodrigues
- Laboratório de Câncer de Mama, Canais Iônicos e AMP Cíclico, Faculdade de Ciências Humanas, Sociais e da Saúde, Universidade FUMEC, Belo Horizonte, MG, Brasil
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14
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Advances in understanding the functions of native GlyT1 and GlyT2 neuronal glycine transporters. Neurochem Int 2016; 99:169-177. [DOI: 10.1016/j.neuint.2016.07.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 07/05/2016] [Accepted: 07/05/2016] [Indexed: 11/20/2022]
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15
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Rizaner N, Onkal R, Fraser SP, Pristerá A, Okuse K, Djamgoz MBA. Intracellular calcium oscillations in strongly metastatic human breast and prostate cancer cells: control by voltage-gated sodium channel activity. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2016; 45:735-748. [PMID: 27665102 DOI: 10.1007/s00249-016-1170-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 06/27/2016] [Accepted: 08/30/2016] [Indexed: 12/21/2022]
Abstract
The possible association of intracellular Ca2+ with metastasis in human cancer cells is poorly understood. We have studied Ca2+ signaling in human prostate and breast cancer cell lines of strongly versus weakly metastatic potential in a comparative approach. Intracellular free Ca2+ was measured using a membrane-permeant fluorescent Ca2+-indicator dye (Fluo-4 AM) and confocal microscopy. Spontaneous Ca2+ oscillations were observed in a proportion of strongly metastatic human prostate and breast cancer cells (PC-3M and MDA-MB-231, respectively). In contrast, no such oscillations were observed in weakly/non metastatic LNCaP and MCF-7 cells, although a rise in the resting Ca2+ level could be induced by applying a high-K+ solution. Various parameters of the oscillations depended on extracellular Ca2+ and voltage-gated Na+ channel activity. Treatment with either tetrodotoxin (a general blocker of voltage-gated Na+ channels) or ranolazine (a blocker of the persistent component of the channel current) suppressed the Ca2+ oscillations. It is concluded that the functional voltage-gated Na+ channel expression in strongly metastatic cancer cells makes a significant contribution to generation of oscillatory intracellular Ca2+ activity. Possible mechanisms and consequences of the Ca2+ oscillations are discussed.
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Affiliation(s)
- Nahit Rizaner
- Department of Life Sciences, Neuroscience Solutions to Cancer Research Group, Sir Alexander Fleming Building, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK. .,Biotechnology Research Centre, Cyprus International University, Haspolat, Mersin, Turkey.
| | - Rustem Onkal
- Department of Life Sciences, Neuroscience Solutions to Cancer Research Group, Sir Alexander Fleming Building, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK.,Biotechnology Research Centre, Cyprus International University, Haspolat, Mersin, Turkey
| | - Scott P Fraser
- Department of Life Sciences, Neuroscience Solutions to Cancer Research Group, Sir Alexander Fleming Building, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK
| | - Alessandro Pristerá
- Department of Life Sciences, Sir Ernst Chain Building, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK
| | - Kenji Okuse
- Department of Life Sciences, Sir Ernst Chain Building, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK
| | - Mustafa B A Djamgoz
- Department of Life Sciences, Neuroscience Solutions to Cancer Research Group, Sir Alexander Fleming Building, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK.,Biotechnology Research Centre, Cyprus International University, Haspolat, Mersin, Turkey
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16
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The Epithelial Sodium Channel and the Processes of Wound Healing. BIOMED RESEARCH INTERNATIONAL 2016; 2016:5675047. [PMID: 27493961 PMCID: PMC4963570 DOI: 10.1155/2016/5675047] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 06/15/2016] [Indexed: 12/19/2022]
Abstract
The epithelial sodium channel (ENaC) mediates passive sodium transport across the apical membranes of sodium absorbing epithelia, like the distal nephron, the intestine, and the lung airways. Additionally, the channel has been involved in the transduction of mechanical stimuli, such as hydrostatic pressure, membrane stretch, and shear stress from fluid flow. Thus, in vascular endothelium, it participates in the control of the vascular tone via its activity both as a sodium channel and as a shear stress transducer. Rather recently, ENaC has been shown to participate in the processes of wound healing, a role that may also involve its activities as sodium transporter and as mechanotransducer. Its presence as the sole channel mediating sodium transport in many tissues and the diversity of its functions probably underlie the complexity of its regulation. This brief review describes some aspects of ENaC regulation, comments on evidence about ENaC participation in wound healing, and suggests possible regulatory mechanisms involved in this participation.
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17
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Rassner MP, Moser A, Follo M, Joseph K, van Velthoven-Wurster V, Feuerstein TJ. Neocortical GABA release at high intracellular sodium and low extracellular calcium: an anti-seizure mechanism. J Neurochem 2016; 137:177-89. [DOI: 10.1111/jnc.13555] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 01/14/2016] [Accepted: 01/22/2016] [Indexed: 11/30/2022]
Affiliation(s)
- Michael P. Rassner
- Section of Clinical Neuropharmacology of the Department of Neurosurgery; University of Freiburg; Freiburg Germany
| | - Andreas Moser
- Neurochemical Research Group; Department of Neurology; University of Lübeck; Lübeck Germany
- Freiburg Institute for Advanced Studies (FRIAS); University of Freiburg; Freiburg Germany
| | - Marie Follo
- Department of Medicine I; Medical Center - University of Freiburg; Freiburg Germany
| | - Kevin Joseph
- Section of Clinical Neuropharmacology of the Department of Neurosurgery; University of Freiburg; Freiburg Germany
- Section of Neuroelectronic Systems of the Department of Neurosurgery; University of Freiburg; Freiburg Germany
| | | | - Thomas J. Feuerstein
- Section of Clinical Neuropharmacology of the Department of Neurosurgery; University of Freiburg; Freiburg Germany
- Freiburg Institute for Advanced Studies (FRIAS); University of Freiburg; Freiburg Germany
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18
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Horváth T, Polony G, Fekete Á, Aller M, Halmos G, Lendvai B, Heinrich A, Sperlágh B, Vizi ES, Zelles T. ATP-Evoked Intracellular Ca²⁺ Signaling of Different Supporting Cells in the Hearing Mouse Hemicochlea. Neurochem Res 2016; 41:364-75. [PMID: 26801171 DOI: 10.1007/s11064-015-1818-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Revised: 12/23/2015] [Accepted: 12/25/2015] [Indexed: 12/01/2022]
Abstract
Hearing and its protection is regulated by ATP-evoked Ca(2+) signaling in the supporting cells of the organ of Corti, however, the unique anatomy of the cochlea hampers observing these mechanisms. For the first time, we have performed functional ratiometric Ca(2+) imaging (fura-2) in three different supporting cell types in the hemicochlea preparation of hearing mice to measure purinergic receptor-mediated Ca(2+) signaling in pillar, Deiters' and Hensen's cells. Their resting [Ca(2+)]i was determined and compared in the same type of preparation. ATP evoked reversible, repeatable and dose-dependent Ca(2+) transients in all three cell types, showing desensitization. Inhibiting the Ca(2+) signaling of the ionotropic P2X (omission of extracellular Ca(2+)) and metabotropic P2Y purinergic receptors (depletion of intracellular Ca(2+) stores) revealed the involvement of both receptor types. Detection of P2X2,3,4,6,7 and P2Y1,2,6,12,14 receptor mRNAs by RT-PCR supported this finding and antagonism by PPADS suggested different functional purinergic receptor population in pillar versus Deiters' and Hensen's cells. The sum of the extra- and intracellular Ca(2+)-dependent components of the response was about equal with the control ATP response (linear additivity) in pillar cells, and showed supralinearity in Deiters' and Hensen's cells. Calcium-induced calcium release might explain this synergistic interaction. The more pronounced Ca(2+) leak from the endoplasmic reticulum in Deiters' and Hensen's cells, unmasked by cyclopiazonic acid, may also suggests the higher activity of the internal stores in Ca(2+) signaling in these cells. Differences in Ca(2+) homeostasis and ATP-induced Ca(2+) signaling might reflect the distinct roles these cells play in cochlear function and pathophysiology.
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Affiliation(s)
- T Horváth
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Nagyvárad tér 4., Budapest, 1089, Hungary.,Department of Otorhinolaryngology, Head and Neck Surgery, Bajcsy-Zsilinszky Hospital, Budapest, Hungary
| | - G Polony
- Department of Otorhinolaryngology, Head and Neck Surgery, Semmelweis University, Budapest, Hungary
| | - Á Fekete
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada
| | - M Aller
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Nagyvárad tér 4., Budapest, 1089, Hungary.,Computational Cognitive Neuroimaging Laboratory, Computational Neuroscience and Cognitive Robotics Centre, University of Birmingham, Birmingham, UK
| | - G Halmos
- Department of Otolaryngology, Head and Neck Surgery, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - B Lendvai
- Pharmacological and Drug Safety Research, Gedeon Richter Plc., Budapest, Hungary
| | - A Heinrich
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - B Sperlágh
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - E S Vizi
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - T Zelles
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Nagyvárad tér 4., Budapest, 1089, Hungary. .,Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary.
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19
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Tang QY, Zhang FF, Xu J, Wang R, Chen J, Logothetis DE, Zhang Z. Epilepsy-Related Slack Channel Mutants Lead to Channel Over-Activity by Two Different Mechanisms. Cell Rep 2015; 14:129-139. [PMID: 26725113 DOI: 10.1016/j.celrep.2015.12.019] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 08/11/2015] [Accepted: 11/23/2015] [Indexed: 01/07/2023] Open
Abstract
Twelve sodium-activated potassium channel (KCNT1, Slack) genetic mutants have been identified from severe early-onset epilepsy patients. The changes in biophysical properties of these mutants and the underlying mechanisms causing disease remain elusive. Here, we report that seven of the 12 mutations increase, whereas one mutation decreases, the channel's sodium sensitivity. Two of the mutants exhibit channel over-activity only when the intracellular Na(+) ([Na(+)]i) concentration is ∼80 mM. In contrast, single-channel data reveal that all 12 mutants increase the maximal open probability (Po). We conclude that these mutant channels lead to channel over-activity predominantly by increasing the ability of sodium binding to activate the channel, which is indicated by its maximal Po. The sodium sensitivity of these epilepsy causing mutants probably determines the [Na(+)]i concentration at which these mutants exert their pathological effects.
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Affiliation(s)
- Qiong-Yao Tang
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical College, Xuzhou, Jiangsu Province 221004, China; Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical College, Xuzhou, Jiangsu Province 221004, China
| | - Fei-Fei Zhang
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical College, Xuzhou, Jiangsu Province 221004, China; Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical College, Xuzhou, Jiangsu Province 221004, China
| | - Jie Xu
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical College, Xuzhou, Jiangsu Province 221004, China; Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical College, Xuzhou, Jiangsu Province 221004, China
| | - Ran Wang
- School of Anesthesiology, Xuzhou Medical College, Xuzhou, Jiangsu Province 221004, China
| | - Jian Chen
- School of Anesthesiology, Xuzhou Medical College, Xuzhou, Jiangsu Province 221004, China
| | - Diomedes E Logothetis
- Department of Physiology and Biophysics, Medical College of Virginia Campus, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Zhe Zhang
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical College, Xuzhou, Jiangsu Province 221004, China; Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical College, Xuzhou, Jiangsu Province 221004, China.
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20
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Guo F, Zhou PD, Gao QH, Gong J, Feng R, Xu XX, Liu SY, Hu HY, Zhao MM, Adam HC, Cai JQ, Hao LY. Low-Mg(2+) treatment increases sensitivity of voltage-gated Na(+) channels to Ca(2+)/calmodulin-mediated modulation in cultured hippocampal neurons. Am J Physiol Cell Physiol 2015; 308:C594-605. [PMID: 25652447 DOI: 10.1152/ajpcell.00174.2014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 01/30/2015] [Indexed: 02/06/2023]
Abstract
Culture of hippocampal neurons in low-Mg(2+) medium (low-Mg(2+) neurons) results in induction of continuous seizure activity. However, the underlying mechanism of the contribution of low Mg(2+) to hyperexcitability of neurons has not been clarified. Our data, obtained using the patch-clamp technique, show that voltage-gated Na(+) channel (VGSC) activity, which is associated with a persistent, noninactivating Na(+) current (INa,P), was modulated by calmodulin (CaM) in a concentration-dependent manner in normal and low-Mg(2+) neurons, but the channel activity was more sensitive to Ca(2+)/CaM regulation in low-Mg(2+) than normal neurons. The increased sensitivity of VGSCs in low-Mg(2+) neurons was partially retained when CaM12 and CaM34, CaM mutants with disabled binding sites in the N or C lobe, were used but was diminished when CaM1234, a CaM mutant in which all four Ca(2+) sites are disabled, was used, indicating that functional Ca(2+)-binding sites from either lobe of CaM are required for modulation of VGSCs in low-Mg(2+) neurons. Furthermore, the number of neurons exhibiting colocalization of CaM with the VGSC subtypes NaV1.1, NaV1.2, and NaV1.3 was significantly higher in low- Mg(2+) than normal neurons, as shown by immunofluorescence. Our main finding is that low-Mg(2+) treatment increases sensitivity of VGSCs to Ca(2+)/CaM-mediated regulation. Our data reveal that CaM, as a core regulating factor, connects the functional roles of the three main intracellular ions, Na(+), Ca(2+), and Mg(2+), by modulating VGSCs and provides a possible explanation for the seizure discharge observed in low-Mg(2+) neurons.
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Affiliation(s)
- Feng Guo
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang, China
| | - Pei-Dong Zhou
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang, China
| | - Qing-Hua Gao
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang, China
| | - Jian Gong
- Department of Clinical Pharmacy, School of Life Science and Biopharmaceutics, Shenyang Pharmaceutical University, Shenyang, China
| | - Rui Feng
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang, China
| | - Xiao-Xue Xu
- Department of Neurology, The First Hospital of China Medical University, Shenyang, China; and
| | - Shu-Yuan Liu
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang, China
| | - Hui-Yuan Hu
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang, China
| | - Mei-Mi Zhao
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang, China
| | - Hogan-Cann Adam
- Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Ji-Qun Cai
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang, China
| | - Li-Ying Hao
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang, China
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21
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Szilágyi T, Száva I, Metz EJ, Mihály I, Orbán-Kis K. Untangling the pathomechanisms of temporal lobe epilepsy—The promise of epileptic biomarkers and novel therapeutic approaches. Brain Res Bull 2014; 109:1-12. [DOI: 10.1016/j.brainresbull.2014.08.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 08/11/2014] [Accepted: 08/14/2014] [Indexed: 12/30/2022]
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22
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GABA release provoked by disturbed Na+, K+ and Ca2+ homeostasis in cerebellar nerve endings: Roles of Ca2+ channels, Na+/Ca2+ exchangers and GAT1 transporter reversal. Neurochem Int 2014; 72:1-9. [DOI: 10.1016/j.neuint.2014.04.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 03/25/2014] [Accepted: 04/03/2014] [Indexed: 11/15/2022]
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23
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Koncz I, Szász BK, Szabó SI, Kiss JP, Mike A, Lendvai B, Sylvester Vizi E, Zelles T. The tricyclic antidepressant desipramine inhibited the neurotoxic, kainate-induced [Ca(2+)]i increases in CA1 pyramidal cells in acute hippocampal slices. Brain Res Bull 2014; 104:42-51. [PMID: 24742525 DOI: 10.1016/j.brainresbull.2014.04.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 03/24/2014] [Accepted: 04/01/2014] [Indexed: 12/18/2022]
Abstract
Kainate (KA), used for modelling neurodegenerative diseases, evokes excitotoxicity. However, the precise mechanism of KA-evoked [Ca(2+)]i increase is unexplored, especially in acute brain slice preparations. We used [Ca(2+)]i imaging and patch clamp electrophysiology to decipher the mechanism of KA-evoked [Ca(2+)]i rise and its inhibition by the tricyclic antidepressant desipramine (DMI) in CA1 pyramidal cells in rat hippocampal slices and in cultured hippocampal cells. The effect of KA was dose-dependent and relied totally on extracellular Ca(2+). The lack of effect of dl-2-amino-5-phosphonopentanoic acid (AP-5) and abolishment of the response by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) suggested the involvement of non-N-methyl-d-aspartate receptors (non-NMDARs). The predominant role of the Ca(2+)-impermeable α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate receptors (AMPARs) in the initiation of the Ca(2+) response was supported by the inhibitory effect of the selective AMPAR antagonist GYKI 53655 and the ineffectiveness of 1-naphthyl acetylspermine (NASPM), an inhibitor of the Ca(2+)-permeable AMPARs. The voltage-gated Ca(2+) channels (VGCC), blocked by ω-Conotoxin MVIIC+nifedipine+NiCl2, contributed to the [Ca(2+)]i rise. VGCCs were also involved, similarly to AMPAR current, in the KA-evoked depolarisation. Inhibition of voltage-gated Na(+) channels (VGSCs; tetrodotoxin, TTX) did not affect the depolarisation of pyramidal cells but blocked the depolarisation-evoked action potential bursts and reduced the Ca(2+) response. The tricyclic antidepressant DMI inhibited the KA-evoked [Ca(2+)]i rise in a dose-dependent manner. It directly attenuated the AMPA-/KAR current, but its more potent inhibition on the Ca(2+) response supports additional effect on VGCCs, VGSCs and Na(+)/Ca(2+) exchangers. The multitarget action on decisive players of excitotoxicity holds out more promise in clinical therapy of neurodegenerative diseases.
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Affiliation(s)
- István Koncz
- Department of Pharmacology & Pharmacotherapy, University of Szeged, Szeged, Hungary
| | - Bernadett K Szász
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Szilárd I Szabó
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | | | - Arpád Mike
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Balázs Lendvai
- Gedeon Richter Plc., Pharmacology and Drug Safety Department, Budapest, Hungary
| | - E Sylvester Vizi
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Tibor Zelles
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary; Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary.
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State-dependent contribution of the hyperpolarization-activated Na+/K+ and persistent Na+ currents to respiratory rhythmogenesis in vivo. J Neurosci 2013; 33:8716-28. [PMID: 23678115 DOI: 10.1523/jneurosci.5066-12.2013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
How rhythms are generated by neuronal networks is fundamental to understand rhythmic behaviors such as respiration, locomotion, and mastication. Respiratory rhythm is generated by the preBötzinger complex (preBötC), an anatomically and functionally discrete population of brainstem neurons, central and necessary for respiratory rhythm. In specific in vitro conditions, preBötC neurons depend on voltage-dependent inward currents to generate respiratory rhythm. In the mature and intact organism, where preBötC neurons are deeply embedded in the respiratory network, the contribution of ionic currents to respiratory rhythm is unclear. We propose that a set of ionic currents plays a key role in generating respiratory rhythm in the mature organism in vivo. By microperfusing ionic current blockers into the preBötC of adult rats, we identify the hyperpolarization-activated cation current as a critical component of the mechanism promoting respiratory rhythm, and that this current, in combination with the persistent sodium current, is essential to respiratory rhythm in vivo. Importantly, both currents contribute to rhythmic activity in states of anesthesia, quiet wakefulness, and sleep, but not when the organism is engaged in active behaviors. These data show that a set of ionic currents at the preBötC imparts the network with rhythmicity in reduced states of arousal, although the network can override their contribution to adjust its activity for nonrhythmic behaviors in active wakefulness.
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Omilusik KD, Nohara LL, Stanwood S, Jefferies WA. Weft, warp, and weave: the intricate tapestry of calcium channels regulating T lymphocyte function. Front Immunol 2013; 4:164. [PMID: 23805141 PMCID: PMC3690356 DOI: 10.3389/fimmu.2013.00164] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 06/11/2013] [Indexed: 12/20/2022] Open
Abstract
Calcium (Ca(2+)) is a universal second messenger important for T lymphocyte homeostasis, activation, proliferation, differentiation, and apoptosis. The events surrounding Ca(2+) mobilization in lymphocytes are tightly regulated and involve the coordination of diverse ion channels, membrane receptors, and signaling molecules. A mechanism termed store-operated Ca(2+) entry (SOCE), causes depletion of endoplasmic reticulum (ER) Ca(2+) stores following T cell receptor (TCR) engagement and triggers a sustained influx of extracellular Ca(2+) through Ca(2+) release-activated Ca(2+) (CRAC) channels in the plasma membrane. The ER Ca(2+) sensing molecule, stromal interaction molecule 1 (STIM1), and a pore-forming plasma membrane protein, ORAI1, have been identified as important mediators of SOCE. Here, we review the role of several additional families of Ca(2+) channels expressed on the plasma membrane of T cells that likely contribute to Ca(2+) influx following TCR engagement, particularly highlighting an important role for voltage-dependent Ca(2+) channels (CaV) in T lymphocyte biology.
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Affiliation(s)
- Kyla D Omilusik
- Michael Smith Laboratories, University of British Columbia , Vancouver, BC , Canada ; Centre for Blood Research, University of British Columbia , Vancouver, BC , Canada ; The Brain Research Centre, University of British Columbia , Vancouver, BC , Canada ; Department of Microbiology and Immunology, University of British Columbia , Vancouver, BC , Canada ; Department of Medical Genetics, University of British Columbia , Vancouver, BC , Canada ; Department of Zoology, University of British Columbia , Vancouver, BC , Canada
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26
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Guo F, Xu X, Cai J, Hu H, Sun W, He G, Shao D, Wang L, Chen T, Shaw C, Zhu T, Hao L. The up-regulation of voltage-gated sodium channels subtypes coincides with an increased sodium current in hippocampal neuronal culture model. Neurochem Int 2013; 62:287-95. [DOI: 10.1016/j.neuint.2013.01.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 12/06/2012] [Accepted: 01/06/2013] [Indexed: 01/24/2023]
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Brackenbury WJ. Voltage-gated sodium channels and metastatic disease. Channels (Austin) 2012; 6:352-61. [PMID: 22992466 DOI: 10.4161/chan.21910] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Voltage-gated Na (+) channels (VGSCs) are macromolecular protein complexes containing a pore-forming α subunit and smaller non-pore-forming β subunits. VGSCs are expressed in metastatic cells from a number of cancers. In these cells, Na (+) current carried by α subunits enhances migration, invasion and metastasis in vivo. In contrast, the β subunits mediate cellular adhesion and process extension. The prevailing hypothesis is that VGSCs are upregulated in cancer, in general favoring an invasive/metastatic phenotype, although the mechanisms are still not fully clear. Expression of the Nav 1.5 α subunit associates with poor prognosis in clinical breast cancer specimens, suggesting that VGSCs may have utility as prognostic markers for cancer progression. Furthermore, repurposing existing VGSC-blocking therapeutic drugs may provide a new strategy to improve outcomes in patients suffering from metastatic disease, which is the major cause of cancer-related deaths, and for which there is currently no cure.
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A voltage-gated sodium channel is essential for the positive selection of CD4(+) T cells. Nat Immunol 2012; 13:880-7. [PMID: 22842345 PMCID: PMC3426661 DOI: 10.1038/ni.2379] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Accepted: 06/26/2012] [Indexed: 12/15/2022]
Abstract
Sustained Ca2+ entry into CD4+CD8+ double-positive thymocytes is required for positive selection. We identified a voltage-gated Na+ channel (VGSC), essential for positive selection of CD4+ T cells. Pharmacological inhibition of VGSC activity inhibitedsustained Ca2+ influx induced by positive-selecting ligands and in vitro positive selection of CD4+ but not CD8+ T cells. In vivo shRNA knockdown of Scn5a specifically inhibited positive selection of CD4+ T cells. Ectopic expression of VGSC in peripheral AND CD4+ T cells bestowed the ability to respond to a positively selecting ligand, directly demonstrating VGSC expression was responsible for increased sensitivity. Thus active VGSCs in thymocytes provide a mechanism by which a weak positive selecting signal can induce sustained Ca2+ signals required for CD4+ T cell development.
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Palty R, Hershfinkel M, Sekler I. Molecular identity and functional properties of the mitochondrial Na+/Ca2+ exchanger. J Biol Chem 2012; 287:31650-7. [PMID: 22822063 DOI: 10.1074/jbc.r112.355867] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The mitochondrial membrane potential that powers the generation of ATP also facilitates mitochondrial Ca(2+) shuttling. This process is fundamental to a wide range of cellular activities, as it regulates ATP production, shapes cytosolic and endoplasmic recticulum Ca(2+) signaling, and determines cell fate. Mitochondrial Ca(2+) transport is mediated primarily by two major transporters: a Ca(2+) uniporter that mediates Ca(2+) uptake and a Na(+)/Ca(2+) exchanger that subsequently extrudes mitochondrial Ca(2+). In this minireview, we focus on the specific role of the mitochondrial Na(+)/Ca(2+) exchanger and describe its ion exchange mechanism, regulation by ions, and putative partner proteins. We discuss the recent molecular identification of the mitochondrial exchanger and how its activity is linked to physiological and pathophysiological processes.
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Affiliation(s)
- Raz Palty
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA. palty35@berkeley
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30
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Characterisation of Nav types endogenously expressed in human SH-SY5Y neuroblastoma cells. Biochem Pharmacol 2012; 83:1562-71. [DOI: 10.1016/j.bcp.2012.02.022] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Accepted: 02/24/2012] [Indexed: 02/05/2023]
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Chao D, He X, Yang Y, Bazzy-Asaad A, Lazarus LH, Balboni G, Kim DH, Xia Y. DOR activation inhibits anoxic/ischemic Na+ influx through Na+ channels via PKC mechanisms in the cortex. Exp Neurol 2012; 236:228-39. [PMID: 22609332 DOI: 10.1016/j.expneurol.2012.05.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Revised: 04/11/2012] [Accepted: 05/09/2012] [Indexed: 01/17/2023]
Abstract
Activation of delta-opioid receptors (DOR) is neuroprotective against hypoxic/ischemic injury in the cortex, which is at least partially related to its action against hypoxic/ischemic disruption of ionic homeostasis that triggers neuronal injury. Na(+) influx through TTX-sensitive voltage-gated Na(+) channels may be a main mechanism for hypoxia-induced disruption of K(+) homeostasis, with DOR activation attenuating the disruption of ionic homeostasis by targeting voltage-gated Na(+) channels. In the present study we examined the role of DOR in the regulation of Na(+) influx in anoxia and simulated ischemia (oxygen-glucose deprivation) as well as the effect of DOR activation on the Na(+) influx induced by a Na(+) channel opener without anoxic/ischemic stress and explored a potential PKC mechanism underlying the DOR action. We directly measured extracellular Na(+) activity in mouse cortical slices with Na(+) selective electrodes and found that (1) anoxia-induced Na(+) influx occurred mainly through TTX-sensitive Na(+) channels; (2) DOR activation inhibited the anoxia/ischemia-induced Na(+) influx; (3) veratridine, a Na(+) channel opener, enhanced the anoxia-induced Na(+) influx; this could be attenuated by DOR activation; (4) DOR activation did not reduce the anoxia-induced Na(+) influx in the presence of chelerythrine, a broad-spectrum PKC blocker; and (5) DOR effects were blocked by PKCβII peptide inhibitor, and PKCθ pseudosubstrate inhibitor, respectively. We conclude that DOR activation inhibits anoxia-induced Na(+) influx through Na(+) channels via PKC (especially PKCβII and PKCθ isoforms) dependent mechanisms in the cortex.
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Affiliation(s)
- Dongman Chao
- The Third Medical College of Soochow University, Changzhou, Jiangsu 213003, PR China
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32
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Aldana BI, Sitges M. Sertraline inhibits pre-synaptic Na⁺ channel-mediated responses in hippocampus-isolated nerve endings. J Neurochem 2012; 121:197-205. [PMID: 22288826 DOI: 10.1111/j.1471-4159.2012.07674.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In the present study, a possible sertraline action on cerebral pre-synaptic Na(+) channels was investigated. For this purpose, the effect of sertraline on responses induced by the Na(+) channel opener, veratridine, namely the increase in Na(+) and in neurotransmitter release in hippocampus-isolated nerve endings was investigated. Results show that sertraline in the low μM range (1.5-25 μM) progressively inhibits the rise in Na(+) and the release of pre-loaded [(3) H]Glu as well as the release of endogenous 5-HT, Glu and GABA (detected by HPLC) induced by veratridine depolarization either under external Ca(2+) -free conditions or in the presence of external Ca(2+) . In addition, under non-depolarized conditions, sertraline (25 μM) increased the external concentration of 5-HT at expense of its internal concentration, and unchanged the external and internal concentrations of the amino acid neurotransmitters and of the 5-HT main metabolite, 5-HIAA. This result is consistent with the sertraline inhibitory action of the serotonin transporter. However, sertraline is unlikely to inhibit pre-synaptic Na(+) channels permeability by increasing external 5-HT. Because 5-HT in a wide concentration range (1-1000 μM) did not change the veratridine-induced increase in Na(+) . In summary, present findings demonstrate that besides the inhibition of 5-HT reuptake, sertraline is an effective inhibitor of pre-synaptic Na(+) channels controlling neurotransmitter release.
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Affiliation(s)
- Blanca I Aldana
- Departamento de Biología Celular y Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, México D.F., México
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Tang Q, Ma J, Zhang P, Wan W, Kong L, Wu L. Persistent sodium current and Na+/H+ exchange contributes to the augmentation of the reverse Na+/Ca2+ exchange during hypoxia or acute ischemia in ventricular myocytes. Pflugers Arch 2012; 463:513-22. [PMID: 22234427 DOI: 10.1007/s00424-011-1070-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Accepted: 12/22/2011] [Indexed: 12/19/2022]
Abstract
The increases in persistent sodium currents (I (Na.P)) and Na(+)/H(+) exchange (NHE) causes intracellular Ca(2+) overload. The objective of this study was to determine the contribution of I (Na.P) and NHE on the hypoxia- or acute ischemia-induced increase in the reverse Na(+)/Ca(2+) exchange current (HIR- or AIR-I (NCX)). I (Na.P) and I (NCX) in rabbit ventricular myocytes were recorded during hypoxia or acute ischemia, combination of acidosis (pH values were 6.0 intracellularly and 6.8 extracellularly) and hypoxia, using whole-cell patch-clamp techniques. The results indicate that (1) under hypoxic condition, the augmentation of both HIR-I (NCX) and I (Na.P) was inhibited by TTX (2 to 8 μM) in a concentration-dependent manner. The inhibitions of I (Na,P) and HIR-I (NCX) reached maximum in the presence of either 4 μM TTX or 10 μM KR-32568 (a NHE inhibitor), respectively. The maximal inhibitions of HIR-I (NCX) by 4 μM TTX and 10 μM KR-32568 were 72.54% and 16.89%, respectively. (2) Administration of 2 μM TTX and 10 μM KR-32568 in either order in the same cells decreased HIR-I (NCX) by 64.83% and 16.94%, respectively. (3) I (Na.P) and the reverse I (NCX) were augmented during acute ischemia. TTX (4 μM) and KR-32568 (10 μM) reduced AIR-I (NCX) by 73.39% and 24.13%, respectively. (4) Under normoxic condition, veratridine (20 μM) significantly increased I (Na.P) and the reverse I (NCX), which was reversed by 4 μM TTX. In conclusion, during hypoxia or acute ischemia, both increased I (Na.P) and NHE contribute to the HIR- or AIR-I (NCX) with the former playing a major role comparing with the latter.
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Affiliation(s)
- Qiong Tang
- Cardio-Electrophysiological Research Laboratory, Medical College, Wuhan University of Science and Technology, Wuhan, Hubei, China
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34
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Mura E, Zappettini S, Preda S, Biundo F, Lanni C, Grilli M, Cavallero A, Olivero G, Salamone A, Govoni S, Marchi M. Dual effect of beta-amyloid on α7 and α4β2 nicotinic receptors controlling the release of glutamate, aspartate and GABA in rat hippocampus. PLoS One 2012; 7:e29661. [PMID: 22253754 PMCID: PMC3256170 DOI: 10.1371/journal.pone.0029661] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Accepted: 12/01/2011] [Indexed: 11/19/2022] Open
Abstract
Background We previously showed that beta-amyloid (Aβ), a peptide considered as relevant to Alzheimer's Disease, is able to act as a neuromodulator affecting neurotransmitter release in absence of evident sign of neurotoxicity in two different rat brain areas. In this paper we focused on the hippocampus, a brain area which is sensitive to Alzheimer's Disease pathology, evaluating the effect of Aβ (at different concentrations) on the neurotransmitter release stimulated by the activation of pre-synaptic cholinergic nicotinic receptors (nAChRs, α4β2 and α7 subtypes). Particularly, we focused on some neurotransmitters that are usually involved in learning and memory: glutamate, aspartate and GABA. Methodology/Findings We used a dual approach: in vivo experiments (microdialysis technique on freely moving rats) in parallel to in vitro experiments (isolated nerve endings derived from rat hippocampus). Both in vivo and in vitro the administration of nicotine stimulated an overflow of aspartate, glutamate and GABA. This effect was greatly inhibited by the highest concentrations of Aβ considered (10 µM in vivo and 100 nM in vitro). In vivo administration of 100 nM Aβ (the lowest concentration considered) potentiated the GABA overflow evoked by nicotine. All these effects were specific for Aβ and for nicotinic secretory stimuli. The in vitro administration of either choline or 5-Iodo-A-85380 dihydrochloride (α7 and α4β2 nAChRs selective agonists, respectively) elicited the hippocampal release of aspartate, glutamate, and GABA. High Aβ concentrations (100 nM) inhibited the overflow of all three neurotransmitters evoked by both choline and 5-Iodo-A-85380 dihydrochloride. On the contrary, low Aβ concentrations (1 nM and 100 pM) selectively acted on α7 subtypes potentiating the choline-induced release of both aspartate and glutamate, but not the one of GABA. Conclusions/Significance The results reinforce the concept that Aβ has relevant neuromodulatory effects, which may span from facilitation to inhibition of stimulated release depending upon the concentration used.
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Affiliation(s)
- Elisa Mura
- Department of Drug Sciences, Centre of Excellence in Applied Biology, University of Pavia, Pavia, Italy
| | - Stefania Zappettini
- Section of Pharmacology and Toxicology, Department of Experimental Medicine, University of Genoa, Genoa, Italy
| | - Stefania Preda
- Department of Drug Sciences, Centre of Excellence in Applied Biology, University of Pavia, Pavia, Italy
| | - Fabrizio Biundo
- Department of Drug Sciences, Centre of Excellence in Applied Biology, University of Pavia, Pavia, Italy
| | - Cristina Lanni
- Department of Drug Sciences, Centre of Excellence in Applied Biology, University of Pavia, Pavia, Italy
| | - Massimo Grilli
- Section of Pharmacology and Toxicology, Department of Experimental Medicine, University of Genoa, Genoa, Italy
| | - Anna Cavallero
- Section of Pharmacology and Toxicology, Department of Experimental Medicine, University of Genoa, Genoa, Italy
| | - Guendalina Olivero
- Section of Pharmacology and Toxicology, Department of Experimental Medicine, University of Genoa, Genoa, Italy
| | - Alessia Salamone
- Section of Pharmacology and Toxicology, Department of Experimental Medicine, University of Genoa, Genoa, Italy
| | - Stefano Govoni
- Department of Drug Sciences, Centre of Excellence in Applied Biology, University of Pavia, Pavia, Italy
- * E-mail:
| | - Mario Marchi
- Section of Pharmacology and Toxicology, Department of Experimental Medicine, University of Genoa, Genoa, Italy
- Centre of Excellence for Biomedical Research, University of Genoa, Genoa, Italy
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Tryba AK, Kaczorowski CC, Ben-Mabrouk F, Elsen FP, Lew SM, Marcuccilli CJ. Rhythmic intrinsic bursting neurons in human neocortex obtained from pediatric patients with epilepsy. Eur J Neurosci 2011; 34:31-44. [PMID: 21722205 DOI: 10.1111/j.1460-9568.2011.07746.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Neocortical oscillations result from synchronized activity of a synaptically coupled network and can be strongly influenced by the intrinsic firing properties of individual neurons. As such, the intrinsic electroresponsive properties of individual neurons may have important implications for overall network function. Rhythmic intrinsic bursting (rIB) neurons are of particular interest, as they are poised to initiate and/or strongly influence network oscillations. Although neocortical rIB neurons have been recognized in multiple species, the current study is the first to identify and characterize rIB neurons in the human neocortex. Using whole-cell current-clamp recordings, rIB neurons (n = 12) are identified in human neocortical tissue resected from pediatric patients with intractable epilepsy. In contrast to human regular spiking neurons (n = 12), human rIB neurons exhibit rhythmic bursts of action potentials at frequencies of 0.1-4 Hz. These bursts persist after blockade of fast excitatory neurotransmission and voltage-gated calcium channels. However, bursting is eliminated by subsequent application of the persistent sodium current (I(NaP)) blocker, riluzole. In the presence of riluzole (either 10 or 20 μm), human rIB neurons no longer burst, but fire tonically like regular spiking neurons. These data demonstrate that I(NaP) plays a critical role in intrinsic oscillatory activity observed in rIB neurons in the human neocortex. It is hypothesized that aberrant changes in I(NaP) expression and/or function may ultimately contribute to neurological diseases that are linked to abnormal network activity, such as epilepsy.
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Affiliation(s)
- Andrew K Tryba
- Department of Physiology, The Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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36
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Romei C, Di Prisco S, Raiteri M, Raiteri L. Glycine release provoked by disturbed Na+, K+ and Ca2+ homeostasis in cerebellar nerve endings: roles of Ca2+ channels, Na+/Ca2+ exchangers and GlyT2 transporter reversal. J Neurochem 2011; 119:50-63. [DOI: 10.1111/j.1471-4159.2011.07401.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Luccini E, Romei C, Di Prisco S, Raiteri M, Raiteri L. Ionic dysregulations typical of ischemia provoke release of glycine and GABA by multiple mechanisms. J Neurochem 2010; 114:1074-84. [PMID: 20524963 DOI: 10.1111/j.1471-4159.2010.06829.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Energy deprivation during ischemia causes dysregulations of ions, particularly sodium, potassium and calcium. Under these conditions, release of neurotransmitters is often enhanced and can occur by multiple mechanisms. The aim of this work was to characterize the modes of exit of glycine and GABA from nerve endings exposed to stimuli known to reproduce some of the ionic changes typical of ischemic conditions. Their approach was chosen instead of application of ischemic conditions because the release evoked during ischemia is mechanistically too heterogeneous. Mouse hippocampus and spinal cord synaptosomes, pre-labeled with [(3)H]glycine or [(3)H]GABA, were exposed in superfusion to 50 mM KCl or to 10 microM veratridine. The evoked overflows differed greatly between the two transmitters and between the two regions examined. Significant portions of the K(+)- and the veratridine-evoked overflows occurred by classical exocytosis. Carrier-mediated release of GABA, but not of glycine, was evoked by high K(+); GABA and, less so, glycine were released through transporter reversal by veratridine. External calcium-dependent overflows were only in part sensitive to omega-conotoxins; significant portions occurred following reversal of the plasmalemmal Na(+)/Ca(2+) exchanger. Finally, a relevant contribution to the overall transmitter overflows came from cytosolic calcium originating through the mitochondrial Na(+)/Ca(2+) exchanger. To conclude, ionic dysregulations typical of ischemia cause neurotransmitter release by heterogeneous mechanisms that differ depending on the transmitters and the CNS regions examined.
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Affiliation(s)
- Elisa Luccini
- Department of Experimental Medicine, University of Genova, Genova, Italy
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Vizi ES, Fekete A, Karoly R, Mike A. Non-synaptic receptors and transporters involved in brain functions and targets of drug treatment. Br J Pharmacol 2010; 160:785-809. [PMID: 20136842 DOI: 10.1111/j.1476-5381.2009.00624.x] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Beyond direct synaptic communication, neurons are able to talk to each other without making synapses. They are able to send chemical messages by means of diffusion to target cells via the extracellular space, provided that the target neurons are equipped with high-affinity receptors. While synaptic transmission is responsible for the 'what' of brain function, the 'how' of brain function (mood, attention, level of arousal, general excitability, etc.) is mainly controlled non-synaptically using the extracellular space as communication channel. It is principally the 'how' that can be modulated by medicine. In this paper, we discuss different forms of non-synaptic transmission, localized spillover of synaptic transmitters, local presynaptic modulation and tonic influence of ambient transmitter levels on the activity of vast neuronal populations. We consider different aspects of non-synaptic transmission, such as synaptic-extrasynaptic receptor trafficking, neuron-glia communication and retrograde signalling. We review structural and functional aspects of non-synaptic transmission, including (i) anatomical arrangement of non-synaptic release sites, receptors and transporters, (ii) intravesicular, intra- and extracellular concentrations of neurotransmitters, as well as the spatiotemporal pattern of transmitter diffusion. We propose that an effective general strategy for efficient pharmacological intervention could include the identification of specific non-synaptic targets and the subsequent development of selective pharmacological tools to influence them.
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Affiliation(s)
- E S Vizi
- Department of Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary.
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