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Amakhin DV, Soboleva EB, Postnikova TY, Tumanova NL, Dubrovskaya NM, Kalinina DS, Vasilev DS, Zaitsev AV. Maternal Hypoxia Increases the Excitability of Neurons in the Entorhinal Cortex and Dorsal Hippocampus of Rat Offspring. Front Neurosci 2022; 16:867120. [PMID: 35495064 PMCID: PMC9042652 DOI: 10.3389/fnins.2022.867120] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 03/16/2022] [Indexed: 01/10/2023] Open
Abstract
Prenatal hypoxia is a widespread condition that causes various disturbances in later life, including aberrant central nervous system development, abnormalities in EEG rhythms, and susceptibility to seizures. Hypoxia in rats on the 14th day of embryogenesis (E14) disrupts cortical neuroblast radial migration, mainly affecting the progenitors of cortical glutamatergic neurons but not GABAergic interneurons or hippocampal neurons. Thus, hypoxia at this time point might affect the development of the neocortex to a greater extent than the hippocampus. In the present study, we investigated the long-term effects of hypoxia on the properties of the pyramidal neurons in the hippocampus and entorhinal cortex (EC) in 3-week-old rats subjected to hypoxia on E14. We observed a reduction in the total number of NeuN-positive neurons in EC but not in the CA1 field of the hippocampus, indicating an increased cell loss in EC. However, the principal neuron electrophysiological characteristics were altered in the EC and hippocampus of animals exposed to hypoxia. The whole-cell patch-clamp recordings revealed a similar increase in input resistance in neurons from the hippocampus and EC. However, the resting membrane potential was increased in the EC neurons only. The recordings of field postsynaptic potentials (fPSPs) in the CA1 hippocampal area showed that both the threshold currents inducing fPSPs and population spikes were lower in hypoxic animals compared to age-matched controls. Using the dosed electroshock paradigm, we found that seizure thresholds were lower in the hypoxic group. Thus, the obtained results suggest that maternal hypoxia during the generation of the pyramidal cortical neurons leads to the increased excitability of neuronal circuitries in the brain of young rats. The increased excitability can be attributed to the changes in intrinsic neuronal properties.
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Affiliation(s)
- Dmitry V. Amakhin
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Elena B. Soboleva
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Tatiana Yu. Postnikova
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Natalia L. Tumanova
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Nadezhda M. Dubrovskaya
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Daria S. Kalinina
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
- Institute of Translational Biomedicine, Saint Petersburg State University, St. Petersburg, Russia
- Daria S. Kalinina,
| | - Dmitrii S. Vasilev
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
- *Correspondence: Dmitrii S. Vasilev,
| | - Aleksey V. Zaitsev
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
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Inoue Y, Sawano T, Yamaguchi N, Inoue S, Takayama A, Nakazawa S, Inagaki S, Nakatani J, Tanaka H. Comparative distribution of
Arcadlin/Protocadherin‐8
mRNA in the intact and ischemic brains of adult mice. J Comp Neurol 2022; 530:2033-2055. [DOI: 10.1002/cne.25319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 02/24/2022] [Accepted: 03/07/2022] [Indexed: 11/12/2022]
Affiliation(s)
- Yosuke Inoue
- Pharmacology Laboratory Department of Biomedical Sciences, College of Life Sciences Ritsumeikan University Shiga Japan
| | - Toshinori Sawano
- Pharmacology Laboratory Department of Biomedical Sciences, College of Life Sciences Ritsumeikan University Shiga Japan
| | - Natsumi Yamaguchi
- Pharmacology Laboratory Department of Biomedical Sciences, College of Life Sciences Ritsumeikan University Shiga Japan
| | - Shota Inoue
- Pharmacology Laboratory Department of Biomedical Sciences, College of Life Sciences Ritsumeikan University Shiga Japan
| | - Akinori Takayama
- Pharmacology Laboratory Department of Biomedical Sciences, College of Life Sciences Ritsumeikan University Shiga Japan
| | - Shuma Nakazawa
- Pharmacology Laboratory Department of Biomedical Sciences, College of Life Sciences Ritsumeikan University Shiga Japan
| | - Shinobu Inagaki
- United Graduate School of Child Development Osaka University Suita Japan
- Department of Physical Therapy Osaka Yukioka College of Health Science Ibaraki Japan
| | - Jin Nakatani
- Pharmacology Laboratory Department of Biomedical Sciences, College of Life Sciences Ritsumeikan University Shiga Japan
| | - Hidekazu Tanaka
- Pharmacology Laboratory Department of Biomedical Sciences, College of Life Sciences Ritsumeikan University Shiga Japan
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Yang YS, Choi JH, Rah JC. Hypoxia with inflammation and reperfusion alters membrane resistance by dynamically regulating voltage-gated potassium channels in hippocampal CA1 neurons. Mol Brain 2021; 14:147. [PMID: 34556177 PMCID: PMC8461870 DOI: 10.1186/s13041-021-00857-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 09/07/2021] [Indexed: 02/01/2023] Open
Abstract
Hypoxia typically accompanies acute inflammatory responses in patients and animal models. However, a limited number of studies have examined the effect of hypoxia in combination with inflammation (Hypo-Inf) on neural function. We previously reported that neuronal excitability in hippocampal CA1 neurons decreased during hypoxia and greatly rebounded upon reoxygenation. We attributed this altered excitability mainly to the dynamic regulation of hyperpolarization-activated cyclic nucleotide-gated cation (HCN) channels and input resistance. However, the molecular mechanisms underlying input resistance changes by Hypo-Inf and reperfusion remained unclear. In the present study, we found that a change in the density of the delayed rectifier potassium current (IDR) can explain the input resistance variability. Furthermore, voltage-dependent inactivation of A-type potassium (IA) channels shifted in the depolarizing direction during Hypo-Inf and reverted to normal upon reperfusion without a significant alteration in the maximum current density. Our results indicate that changes in the input resistance, and consequently excitability, caused by Hypo-Inf and reperfusion are at least partially regulated by the availability and voltage dependence of KV channels. Moreover, these results suggest that selective KV channel modulators can be used as potential neuroprotective drugs to minimize hypoxia- and reperfusion-induced neuronal damage.
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Affiliation(s)
- Yoon-Sil Yang
- Korea Brain Research Institute, 61 Cheomdan-ro, Dong-gu, Daegu, 41062 South Korea
| | - Joon Ho Choi
- Korea Brain Research Institute, 61 Cheomdan-ro, Dong-gu, Daegu, 41062 South Korea
| | - Jong-Cheol Rah
- Korea Brain Research Institute, 61 Cheomdan-ro, Dong-gu, Daegu, 41062 South Korea
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology, 333 Techno Jungang-daero, Dalseong-gun, Daegu, 42988 South Korea
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4
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Bormann D, Stojanovic T, Cicvaric A, Schuld GJ, Cabatic M, Ankersmit HJ, Monje FJ. miRNA-132/212 Gene-Deletion Aggravates the Effect of Oxygen-Glucose Deprivation on Synaptic Functions in the Female Mouse Hippocampus. Cells 2021; 10:1709. [PMID: 34359879 PMCID: PMC8306255 DOI: 10.3390/cells10071709] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 07/01/2021] [Accepted: 07/02/2021] [Indexed: 12/29/2022] Open
Abstract
Cerebral ischemia and its sequelae, which include memory impairment, constitute a leading cause of disability worldwide. Micro-RNAs (miRNA) are evolutionarily conserved short-length/noncoding RNA molecules recently implicated in adaptive/maladaptive neuronal responses to ischemia. Previous research independently implicated the miRNA-132/212 cluster in cholinergic signaling and synaptic transmission, and in adaptive/protective mechanisms of neuronal responses to hypoxia. However, the putative role of miRNA-132/212 in the response of synaptic transmission to ischemia remained unexplored. Using hippocampal slices from female miRNA-132/212 double-knockout mice in an established electrophysiological model of ischemia, we here describe that miRNA-132/212 gene-deletion aggravated the deleterious effect of repeated oxygen-glucose deprivation insults on synaptic transmission in the dentate gyrus, a brain region crucial for learning and memory functions. We also examined the effect of miRNA-132/212 gene-deletion on the expression of key mediators in cholinergic signaling that are implicated in both adaptive responses to ischemia and hippocampal neural signaling. miRNA-132/212 gene-deletion significantly altered hippocampal AChE and mAChR-M1, but not α7-nAChR or MeCP2 expression. The effects of miRNA-132/212 gene-deletion on hippocampal synaptic transmission and levels of cholinergic-signaling elements suggest the existence of a miRNA-132/212-dependent adaptive mechanism safeguarding the functional integrity of synaptic functions in the acute phase of cerebral ischemia.
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Affiliation(s)
- Daniel Bormann
- Center for Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, Schwarzspanierstraße 17, 1090 Vienna, Austria; (D.B.); (T.S.); (G.J.S.); (M.C.)
- Laboratory for Cardiac and Thoracic Diagnosis, Department of Surgery, Regeneration and Applied Immunology, Medical University of Vienna, Research Laboratories Vienna General Hospital, Waehringer Guertel 18-20, 1090 Vienna, Austria;
- Division of Thoracic Surgery, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
| | - Tamara Stojanovic
- Center for Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, Schwarzspanierstraße 17, 1090 Vienna, Austria; (D.B.); (T.S.); (G.J.S.); (M.C.)
| | - Ana Cicvaric
- Department of Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, New York, NY 10461, USA;
| | - Gabor J. Schuld
- Center for Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, Schwarzspanierstraße 17, 1090 Vienna, Austria; (D.B.); (T.S.); (G.J.S.); (M.C.)
| | - Maureen Cabatic
- Center for Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, Schwarzspanierstraße 17, 1090 Vienna, Austria; (D.B.); (T.S.); (G.J.S.); (M.C.)
| | - Hendrik Jan Ankersmit
- Laboratory for Cardiac and Thoracic Diagnosis, Department of Surgery, Regeneration and Applied Immunology, Medical University of Vienna, Research Laboratories Vienna General Hospital, Waehringer Guertel 18-20, 1090 Vienna, Austria;
- Division of Thoracic Surgery, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria
- Aposcience AG, Dresdner Straße 87/A 21, 1200 Vienna, Austria
| | - Francisco J. Monje
- Center for Physiology and Pharmacology, Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, Schwarzspanierstraße 17, 1090 Vienna, Austria; (D.B.); (T.S.); (G.J.S.); (M.C.)
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Pan W, Song X, Hu Q, Zhang Y. miR-485 inhibits histone deacetylase HDAC5, HIF1α and PFKFB3 expression to alleviate epilepsy in cellular and rodent models. Aging (Albany NY) 2021; 13:14416-14432. [PMID: 34021541 PMCID: PMC8202868 DOI: 10.18632/aging.203058] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 10/05/2020] [Indexed: 01/15/2023]
Abstract
We investigated the role of microRNA (miR)-485 and its downstream signaling molecules on mediating epilepsy in cellular and rat models. We established a cellular epilepsy model by exposing hippocampal neurons to magnesium and a rat model by treating ICR mice with lithium chloride (127 mg/kg) and pilocarpine (30 mg/kg). We confirmed that miR-485 could bind and inhibit histone deacetylase 5 (HDAC5) and then measured expression of miR-485 and in mice and cells. Cells were transfected with overexpression or knockdown of miR-485, HDAC5, hypoxia-inducible factor-1alpha (HIF1α), or 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 enzyme (PFKFB3) to verify their roles in apoptosis, oxidative stress, and inflammation in epileptic hippocampal neurons. Binding relationship between miR-485, HDAC5, HIF1α, and PFKFB3 was verified. Oxidative stress and inflammation marker levels in epilepsy model mice were assessed. miR-485 was downregulated and HDAC5 was upregulated in cell and animal model of epilepsy. Seizure, neuronal apoptosis, oxidative stress (increased SOD and GSH-Px expression and decreased MDA and 8-OHdG expression) and inflammation (reduced IL-1β, TNF-α, and IL-6 expression) were reduced by miR-485 in epileptic cells. HIF1α and PFKFB3 expression was reduced by HDAC5 knockdown in cells, which was recapitulated in vivo. Thus, miR-485 alleviates neuronal damage and epilepsy by inhibiting HDAC5, HIF1α, and PFKFB3.
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Affiliation(s)
- Wei Pan
- Department of Pediatrics, The Second Hospital of Jilin University, Changchun 130041, P.R. China
| | - Xingyu Song
- Department of Pediatrics, The Second Hospital of Jilin University, Changchun 130041, P.R. China
| | - Qibo Hu
- Department of Pediatrics, The Second Hospital of Jilin University, Changchun 130041, P.R. China
| | - Yunfeng Zhang
- Department of Pediatrics, The Second Hospital of Jilin University, Changchun 130041, P.R. China
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Mishra P, Narayanan R. Ion-channel regulation of response decorrelation in a heterogeneous multi-scale model of the dentate gyrus. CURRENT RESEARCH IN NEUROBIOLOGY 2021; 2:100007. [PMID: 33997798 PMCID: PMC7610774 DOI: 10.1016/j.crneur.2021.100007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Heterogeneities in biological neural circuits manifest in afferent connectivity as well as in local-circuit components such as neuronal excitability, neural structure and local synaptic strengths. The expression of adult neurogenesis in the dentate gyrus (DG) amplifies local-circuit heterogeneities and guides heterogeneities in afferent connectivity. How do neurons and their networks endowed with these distinct forms of heterogeneities respond to perturbations to individual ion channels, which are known to change under several physiological and pathophysiological conditions? We sequentially traversed the ion channels-neurons-network scales and assessed the impact of eliminating individual ion channels on conductance-based neuronal and network models endowed with disparate local-circuit and afferent heterogeneities. We found that many ion channels differentially contributed to specific neuronal or network measurements, and the elimination of any given ion channel altered several functional measurements. We then quantified the impact of ion-channel elimination on response decorrelation, a well-established metric to assess the ability of neurons in a network to convey complementary information, in DG networks endowed with different forms of heterogeneities. Notably, we found that networks constructed with structurally immature neurons exhibited functional robustness, manifesting as minimal changes in response decorrelation in the face of ion-channel elimination. Importantly, the average change in output correlation was dependent on the eliminated ion channel but invariant to input correlation. Our analyses suggest that neurogenesis-driven structural heterogeneities could assist the DG network in providing functional resilience to molecular perturbations. Perturbations at one scale result in a cascading impact on physiology across scales. Heterogeneous multi-scale models used to assess the impact of ion-channel deletion. Mapping of structural components to functional outcomes is many-to-many. Differential & variable impact of ion channel deletion on response decorrelation. Neurogenesis-induced structural heterogeneity confers resilience to perturbations.
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Affiliation(s)
- Poonam Mishra
- Cellular Neurophysiology Laboratory, Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
| | - Rishikesh Narayanan
- Cellular Neurophysiology Laboratory, Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India
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7
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Pospelov AS, Puskarjov M, Kaila K, Voipio J. Endogenous brain-sparing responses in brain pH and PO 2 in a rodent model of birth asphyxia. Acta Physiol (Oxf) 2020; 229:e13467. [PMID: 32174009 DOI: 10.1111/apha.13467] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 03/11/2020] [Indexed: 12/12/2022]
Abstract
AIM To study brain-sparing physiological responses in a rodent model of birth asphyxia which reproduces the asphyxia-defining systemic hypoxia and hypercapnia. METHODS Steady or intermittent asphyxia was induced for 15-45 minutes in anaesthetized 6- and 11-days old rats and neonatal guinea pigs using gases containing 5% or 9% O2 plus 20% CO2 (in N2 ). Hypoxia and hypercapnia were induced with low O2 and high CO2 respectively. Oxygen partial pressure (PO2 ) and pH were measured with microsensors within the brain and subcutaneous ("body") tissue. Blood lactate was measured after asphyxia. RESULTS Brain and body PO2 fell to apparent zero with little recovery during 5% O2 asphyxia and 5% or 9% O2 hypoxia, and increased more than twofold during 20% CO2 hypercapnia. Unlike body PO2 , brain PO2 recovered rapidly to control after a transient fall (rat), or was slightly higher than control (guinea pig) during 9% O2 asphyxia. Asphyxia (5% O2 ) induced a respiratory acidosis paralleled by a progressive metabolic (lact)acidosis that was much smaller within than outside the brain. Hypoxia (5% O2 ) produced a brain-confined alkalosis. Hypercapnia outlasting asphyxia suppressed pH recovery and prolonged the post-asphyxia PO2 overshoot. All pH changes were accompanied by consistent shifts in the blood-brain barrier potential. CONCLUSION Regardless of brain maturation stage, hypercapnia can restore brain PO2 and protect the brain against metabolic acidosis despite compromised oxygen availability during asphyxia. This effect extends to the recovery phase if normocapnia is restored slowly, and it is absent during hypoxia, demonstrating that exposure to hypoxia does not mimic asphyxia.
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Affiliation(s)
- Alexey S. Pospelov
- Faculty of Biological and Environmental Sciences, Molecular and Integrative Biosciences University of Helsinki Helsinki Finland
| | - Martin Puskarjov
- Faculty of Biological and Environmental Sciences, Molecular and Integrative Biosciences University of Helsinki Helsinki Finland
| | - Kai Kaila
- Faculty of Biological and Environmental Sciences, Molecular and Integrative Biosciences University of Helsinki Helsinki Finland
- Neuroscience Center (HiLIFE) University of Helsinki Helsinki Finland
| | - Juha Voipio
- Faculty of Biological and Environmental Sciences, Molecular and Integrative Biosciences University of Helsinki Helsinki Finland
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Whitmire LE, Ling L, Bugay V, Carver CM, Timilsina S, Chuang HH, Jaffe DB, Shapiro MS, Cavazos JE, Brenner R. Downregulation of KCNMB4 expression and changes in BK channel subtype in hippocampal granule neurons following seizure activity. PLoS One 2017; 12:e0188064. [PMID: 29145442 PMCID: PMC5690595 DOI: 10.1371/journal.pone.0188064] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 10/31/2017] [Indexed: 11/25/2022] Open
Abstract
A major challenge is to understand maladaptive changes in ion channels that sets neurons on a course towards epilepsy development. Voltage- and calcium-activated K+ (BK) channels contribute to early spike timing in neurons, and studies indicate that the BK channel plays a pathological role in increasing excitability early after a seizure. Here, we have investigated changes in BK channels and their accessory β4 subunit (KCNMB4) in dentate gyrus (DG) granule neurons of the hippocampus, key neurons that regulate excitability of the hippocampus circuit. Two days after pilocarpine-induced seizures, we found that the predominant effect is a downregulation of the β4 accessory subunit mRNA. Consistent with reduced expression, single channel recording and pharmacology indicate a switch in the subtype of channels expressed; from iberiotoxin-resistant, type II BK channels (BK α/β4) that have higher channel open probability and slow gating, to iberiotoxin-sensitive type I channels (BK α alone) with low open probability and faster gating. The switch to a majority of type I channel expression following seizure activity is correlated with a loss of BK channel function on spike threshold while maintaining the channel’s contribution to increased early spike frequency. Using heterozygous β4 knockout mice, we find reduced expression is sufficient to increase seizure sensitivity. We conclude that seizure-induced downregulation of KCNMB4 is an activity dependent mechanism that increases the excitability of DG neurons. These novel findings indicate that BK channel subtypes are not only defined by cell-specific expression, but can also be plastic depending on the recent history of neuronal excitability.
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Affiliation(s)
- Luke E. Whitmire
- Department of Cell and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Ling Ling
- Department of Cell and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Vladslav Bugay
- Department of Cell and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Chase M. Carver
- Department of Cell and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Santosh Timilsina
- Department of Cell and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Hui-Hsiu Chuang
- Department of Cell and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - David B. Jaffe
- Department of Biology, University of Texas at San Antonio, San Antonio, Texas, United States of America
| | - Mark S. Shapiro
- Department of Cell and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Jose E. Cavazos
- Neurology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Robert Brenner
- Department of Cell and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
- * E-mail:
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Abstract
This review attempts to give a concise and up-to-date overview on the role of potassium channels in epilepsies. Their role can be defined from a genetic perspective, focusing on variants and de novo mutations identified in genetic studies or animal models with targeted, specific mutations in genes coding for a member of the large potassium channel family. In these genetic studies, a demonstrated functional link to hyperexcitability often remains elusive. However, their role can also be defined from a functional perspective, based on dynamic, aggravating, or adaptive transcriptional and posttranslational alterations. In these cases, it often remains elusive whether the alteration is causal or merely incidental. With ∼80 potassium channel types, of which ∼10% are known to be associated with epilepsies (in humans) or a seizure phenotype (in animals), if genetically mutated, a comprehensive review is a challenging endeavor. This goal may seem all the more ambitious once the data on posttranslational alterations, found both in human tissue from epilepsy patients and in chronic or acute animal models, are included. We therefore summarize the literature, and expand only on key findings, particularly regarding functional alterations found in patient brain tissue and chronic animal models.
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Affiliation(s)
- Rüdiger Köhling
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock 18057, Germany
| | - Jakob Wolfart
- Oscar Langendorff Institute of Physiology, University of Rostock, Rostock 18057, Germany
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Zou Z, Lu Y, Zha Y, Yang H. Endocannabinoid 2-Arachidonoylglycerol Suppresses LPS-Induced Inhibition of A-Type Potassium Channel Currents in Caudate Nucleus Neurons Through CB1 Receptor. J Mol Neurosci 2016; 59:493-503. [PMID: 27129498 DOI: 10.1007/s12031-016-0761-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 04/22/2016] [Indexed: 01/29/2023]
Abstract
Inflammation plays a pivotal role in the pathogenesis of many diseases in the central nervous system. Caudate nucleus (CN), the largest nucleus in the brain, is also implicated in many neurological disorders. 2-Arachidonoylglycerol (2-AG), the most abundant endogenous cannabinoid, has been shown to exhibit neuroprotective effects through its anti-inflammatory action from some proinflammatory stimuli. However, the neuroprotective mechanism of 2-AG is complex and has not been fully understood. A-type K(+) channels critically regulate neuronal excitability and have been demonstrated to be associated with some nervous system diseases. The aim of this study was to explore whether A-type K(+) channels were involved in neurotoxicity of lipopolysaccharides (LPS) and the neuroprotective mechanism of 2-AG in CN neurons. Whole cell patch clamp recording was used to investigate the influence of LPS on the function of A-type K(+) channels and its modulation by 2-AG in primary cultured rat CN neurons. Our findings showed that in cultured CN neurons, LPS significantly decreased the A-type potassium currents (I A) in a voltage-insensitive way. The further data demonstrated that an elevation of 2-AG levels by directly applying exogenous 2-AG or inhibiting monoacylglycerol lipase (MAGL) to prevent 2-AG hydrolysis was capable of suppressing the LPS-induced inhibition of IA and the action of 2-AG is mediated through CB1 receptor-dependant way. The study provides a better understanding of inflammation-related neurological disorders and suggests the therapeutic potential for 2-AG for the treatment of these diseases.
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Affiliation(s)
- Ziliang Zou
- Department of Physiology and Pathophysiology, College of Medical Sciences, China Three Gorges University, 8 University Road, 443002, Yichang, Hubei, People's Republic of China
| | - Yongli Lu
- Department of Physiology and Pathophysiology, College of Medical Sciences, China Three Gorges University, 8 University Road, 443002, Yichang, Hubei, People's Republic of China.,Third-Grade Pharmacological Laboratory on Chinese Medicine Approved by State Administration of Traditional Chinese Medicine, China Three Gorges University, 443002, Yichang, Hubei, People's Republic of China
| | - Yunhong Zha
- Department of Neurology, The First Hospital of Yichang, Institute of Translational Neuroscience, Three Gorges University College of Medicine, 443000, Yichang, Hubei, People's Republic of China
| | - Hongwei Yang
- Department of Physiology and Pathophysiology, College of Medical Sciences, China Three Gorges University, 8 University Road, 443002, Yichang, Hubei, People's Republic of China. .,Third-Grade Pharmacological Laboratory on Chinese Medicine Approved by State Administration of Traditional Chinese Medicine, China Three Gorges University, 443002, Yichang, Hubei, People's Republic of China.
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11
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Lopez-Rojas J, Heine M, Kreutz MR. Plasticity of intrinsic excitability in mature granule cells of the dentate gyrus. Sci Rep 2016; 6:21615. [PMID: 26857841 PMCID: PMC4746665 DOI: 10.1038/srep21615] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 01/27/2016] [Indexed: 01/08/2023] Open
Abstract
The dentate gyrus is the main entry gate for cortical input to the hippocampus and one of the few brain areas where adult neurogenesis occurs. Several studies have shown that it is relatively difficult to induce synaptic plasticity in mature but not in newborn dentate granule cells. In the present work we have systematically addressed how classical protocols to induce synaptic plasticity affect action potential firing and intrinsic excitability in mature granule cells. We found that stimulation paradigms considered to be relevant for learning processes consistently modified the probability to generate action potentials in response to a given synaptic input in mature cells, in some paradigms even without any modification of synaptic strength. Collectively the results suggest that plasticity of intrinsic dendritic excitability has a lower induction-threshold than synaptic plasticity in mature granule cells and that this form of plasticity might be an important mechanism by which mature granule cells contribute to hippocampal function.
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Affiliation(s)
- Jeffrey Lopez-Rojas
- Research Group 'Neuroplasticity', Leibniz Institute for Neurobiology, Brenneckestrasse 6, D-39118 Magdeburg, Germany
| | - Martin Heine
- Research Group 'Molecular Physiology', Leibniz Institute for Neurobiology, Brenneckestrasse 6, D-39118 Magdeburg, Germany
| | - Michael R Kreutz
- Research Group 'Neuroplasticity', Leibniz Institute for Neurobiology, Brenneckestrasse 6, D-39118 Magdeburg, Germany.,Leibniz Group 'Dendritic Organelles and Synaptic Function', University Medical Center Hamburg-Eppendorf, Center for Molecular Neurobiology, ZMNH, 20251 Hamburg, Germany
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MRI tracking of bone marrow mesenchymal stem cells labeled with ultra-small superparamagnetic iron oxide nanoparticles in a rat model of temporal lobe epilepsy. Neurosci Lett 2015; 606:30-5. [PMID: 26318841 DOI: 10.1016/j.neulet.2015.08.040] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 08/21/2015] [Accepted: 08/21/2015] [Indexed: 12/25/2022]
Abstract
Transplantation of bone marrow mesenchymal stem cells (BMSCs) is a promising approach for treatment of epilepsy. To our knowledge, there is little research on magnetic resonance imaging (MRI) tracking of BMSCs labeled with ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles in a rat model of temporal lobe epilepsy (TLE). In this study, BMSCs were pre-labeled with USPIO nanoparticles, and then the cell apoptosis, proliferation, surface antigens, and multipotency were investigated. Lithium chloride-pilocarpine induced TLE models were administered by USPIO-labeled BMSCs (U-BMSCs), BMSCs, and saline through lateral ventricle injection as the experimental group, control I group and control II group, respectively, followed by MRI examination, electroencephalography (EEG) and Prussian blue staining. The cell experimental results showed that the labeled USPIO did not affect the biological characteristics and multiple potential of BMSCs. The U-BMSCs can be detected using MRI in vitro and in vivo, and observed in the hippocampus and adjacent parahippocampal cortical areas of the epileptic model. Moreover, electroencephalographic results showed that transplanted U-BMSCs, as well as BMSCs, were capable of reducing the number of epileptiform waves significantly (P<0.01) compared with control II group. All of these findings suggest that it is feasible to track transplanted BMSCs using MRI in a rat model of TLE, and support that USPIO labeling is a valuable tool for cell tracking in the study of seizure disorders.
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Long Q, Fan C, Kai W, Luo Q, Xin W, Wang P, Wang A, Wang Z, Han R, Fei Z, Qiu B, Liu W. Hypoxia inducible factor-1α expression is associated with hippocampal apoptosis during epileptogenesis. Brain Res 2014; 1590:20-30. [DOI: 10.1016/j.brainres.2014.09.028] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 09/07/2014] [Accepted: 09/11/2014] [Indexed: 12/11/2022]
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Liu YQ, Huang WX, Sanchez RM, Min JW, Hu JJ, He XH, Peng BW. Regulation of Kv4.2 A-Type Potassium Channels in HEK-293 Cells by Hypoxia. Front Cell Neurosci 2014; 8:329. [PMID: 25352783 PMCID: PMC4196569 DOI: 10.3389/fncel.2014.00329] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 09/29/2014] [Indexed: 11/13/2022] Open
Abstract
We previously observed that A-type potassium currents were decreased and membrane excitability increased in hippocampal dentate granule cells after neonatal global hypoxia associated with seizures. Here, we studied the effects of hypoxia on the function and expression of Kv4.2 and Kv4.3 α subunit channels, which encode rapidly inactivating A-type K currents, in transfected HEK-293 cells to determine if hypoxia alone could regulate IAin vitro. Global hypoxia in neonatal rat pups resulted in early decreased hippocampal expression of Kv4.2 mRNA and protein with 6 or 12 h post-hypoxia. Whole-cell voltage-clamp recordings revealed that similar times after hypoxia (1%) in vitro decreased peak currents mediated by recombinant Kv4.2 but not Kv4.3 channels. Hypoxia had no significant effect on the voltage-dependencies of activation and inactivation of Kv4.2 channels, but increased the time constant of activation. The same result was observed when Kv4.2 and Kv4.3 channels were co-expressed in a 1:1 ratio. These data suggested that hypoxia directly modulates A-type potassium channels of the subfamily typically expressed in principal hippocampal neurons, and does so in a manner to decrease function. Given the role of IA to slow action potential firing, these data are consistent with a direct effect of hypoxia to decrease IA as a mechanism of increased neuronal excitability and promotion of seizures.
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Affiliation(s)
- Yu-Qiang Liu
- Department of Physiology, Hubei Provincial Key Laboratory of Developmentally Originated Disorder, School of Basic Medical Sciences, Wuhan University , Wuhan , China
| | - Wen-Xian Huang
- Department of Physiology, Hubei Provincial Key Laboratory of Developmentally Originated Disorder, School of Basic Medical Sciences, Wuhan University , Wuhan , China
| | - Russell M Sanchez
- Department of Surgery, College of Medicine, Texas A&M Health Science Center, Neuroscience Institute, Scott and White Hospital, Central Texas Veterans Health Care System , Temple, TX , USA
| | - Jia-Wei Min
- Department of Physiology, Hubei Provincial Key Laboratory of Developmentally Originated Disorder, School of Basic Medical Sciences, Wuhan University , Wuhan , China
| | - Jiang-Jian Hu
- Department of Physiology, Hubei Provincial Key Laboratory of Developmentally Originated Disorder, School of Basic Medical Sciences, Wuhan University , Wuhan , China
| | - Xiao-Hua He
- Department of Physiology, Hubei Provincial Key Laboratory of Developmentally Originated Disorder, School of Basic Medical Sciences, Wuhan University , Wuhan , China
| | - Bi-Wen Peng
- Department of Physiology, Hubei Provincial Key Laboratory of Developmentally Originated Disorder, School of Basic Medical Sciences, Wuhan University , Wuhan , China
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McClendon E, Chen K, Gong X, Sharifnia E, Hagen M, Cai V, Shaver DC, Riddle A, Dean JM, Gunn AJ, Mohr C, Kaplan JS, Rossi DJ, Kroenke CD, Hohimer AR, Back SA. Prenatal cerebral ischemia triggers dysmaturation of caudate projection neurons. Ann Neurol 2014; 75:508-24. [PMID: 24395459 DOI: 10.1002/ana.24100] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Revised: 12/15/2013] [Accepted: 12/31/2013] [Indexed: 01/15/2023]
Abstract
OBJECTIVE Recently, we reported that the neocortex displays impaired growth after transient cerebral hypoxia-ischemia (HI) at preterm gestation that is unrelated to neuronal death but is associated with decreased dendritic arbor complexity of cortical projection neurons. We hypothesized that these morphological changes constituted part of a more widespread neuronal dysmaturation response to HI in the caudate nucleus (CN), which contributes to motor and cognitive disability in preterm survivors. METHODS Ex vivo magnetic resonance imaging (MRI), immunohistochemistry, and Golgi staining defined CN growth, cell death, proliferation, and dendritic maturation in preterm fetal sheep 4 weeks after HI. Patch-clamp recording was used to analyze glutamatergic synaptic currents in CN neurons. RESULTS MRI-defined growth of the CN was reduced after ischemia compared to controls. However, no significant acute or delayed neuronal death was seen in the CN or white matter. Nor was there significant loss of calbindin-positive medium spiny projection neurons (MSNs) or CN interneurons expressing somatostatin, calretinin, parvalbumin, or tyrosine hydroxylase. Morphologically, ischemic MSNs showed a markedly immature dendritic arbor, with fewer dendritic branches, nodes, endings, and spines. The magnitude and kinetics of synaptic currents, and the relative contribution of glutamate receptor subtypes in the CN were significantly altered. INTERPRETATION The marked MSN dendritic and functional abnormalities after preterm cerebral HI, despite the marked resistance of immature CN neurons to cell death, are consistent with widespread susceptibility of projection neurons to HI-induced dysmaturation. These global disturbances in dendritic maturation and glutamatergic synaptic transmission suggest a new mechanism for long-term motor and behavioral disabilities in preterm survivors via widespread disruption of neuronal connectivity.
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Affiliation(s)
- Evelyn McClendon
- Department of Pediatrics, Oregon Health and Science University, Portland, OR
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