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Developmental high voltage

Nicole A Hawkins, Nicole J Zachwieja, Alison R Miller, Lyndsey L Anderson, Jennifer A Kearney
A substantial number of mutations have been identified in voltage-gated sodium channel genes that result in various forms of human epilepsy. SCN1A mutations result in a spectrum of severity ranging from mild febrile seizures to Dravet syndrome, an infant-onset epileptic encephalopathy. Dravet syndrome patients experience multiple seizures types that are often refractory to treatment, developmental delays, and elevated risk for SUDEP. The same sodium channel mutation can produce epilepsy phenotypes of varying clinical severity...
October 2016: PLoS Genetics
Tackmin Kwon
The efficiency of Agrobacterium-mediated transformation in plants depends on the virulence of Agrobacterium strains, the plant tissue culture conditions, and the susceptibility of host plants. Understanding the molecular interactions between Agrobacterium and host plant cells is crucial when manipulating the susceptibility of recalcitrant crop plants and protecting orchard trees from crown gall disease. It was discovered that Arabidopsis voltage-dependent anion channel 1 (atvdac1) mutant has drastic effects on Agrobacterium-mediated tumorigenesis and growth developmental phenotypes, and that these effects are dependent on a Ws-0 genetic background...
September 2016: Molecules and Cells
Bryan S Barker, Matteo Ottolini, Jacy L Wagnon, Rachel M Hollander, Miriam H Meisler, Manoj K Patel
OBJECTIVE: SCN8A encephalopathy (early infantile epileptic encephalopathy; EIEE13) is caused by gain-of-function mutations resulting in hyperactivity of the voltage-gated sodium channel Nav 1.6. The channel is concentrated at the axon initial segment (AIS) and is involved in establishing neuronal excitability. Clinical features of SCN8A encephalopathy include seizure onset between 0 and 18 months of age, intellectual disability, and developmental delay. Seizures are often refractory to treatment with standard antiepileptic drugs, and sudden unexpected death in epilepsy (SUDEP) has been reported in approximately 10% of patients...
September 2016: Epilepsia
Behrouz Moshrefi-Ravasdjani, Pavel Dublin, Gerald Seifert, Katja Jennissen, Christian Steinhäuser, Karl W Kafitz, Christine R Rose
Besides astrocytes and oligodendrocytes, NG2 proteoglycan-expressing cells (NG2 glia) represent a third subtype of macroglia in the brain. Originally described as oligodendrocyte precursor cells, they feature several characteristics not expected from mere progenitor cells, including synaptic connections with neurons. There is accumulating evidence that the properties of NG2 glia differ between different brain regions and developmental stages. To further analyze this proposed heterogeneity, we studied electrophysiological properties, transcript and protein expression, distribution and proliferative capacity of NG2 glia during postnatal development, focusing on the hippocampus and corpus callosum...
June 15, 2016: Brain Structure & Function
G Anand, F Collett-White, A Orsini, S Thomas, S Jayapal, N Trump, Z Zaiwalla, S Jayawant
BACKGROUND: Mutations in SCN8A, coding for the voltage-gated sodium channel Nav 1.6, have been described in relation to infantile onset epilepsy with developmental delay and cognitive impairment, in particular early onset epileptic encephalopathy (EIEE) type 13. CASE REPORT: Here we report an infant and his father with early onset focal epileptic seizures but without cognitive or neurological impairment in whom next generation sequence analysis identified a heterozygous mutation (c...
September 2016: European Journal of Paediatric Neurology: EJPN
Hui Hong, Lisia Rollman, Brooke Feinstein, Jason Tait Sanchez
Ultrafast and temporally precise action potentials (APs) are biophysical specializations of auditory brainstem neurons; properties necessary for encoding sound localization and communication cues. Fundamental to these specializations are voltage dependent potassium (KV) and sodium (NaV) ion channels. Here, we characterized the functional development of these ion channels and quantified how they shape AP properties in the avian cochlear nucleus magnocellularis (NM). We report that late developing NM neurons (embryonic [E] days 19-21) generate fast APs that reliably phase lock to sinusoidal inputs at 75 Hz...
2016: Frontiers in Cellular Neuroscience
Edwin Murenzi, Abigail C Toltin, Steven B Symington, Molly M Morgan, John M Clark
Microtransplantation of mammalian brain neurolemma into the plasma membrane of Xenopus oocytes is used to study ion channels in their native form as they appear in the central nervous system. Use of microtransplanted neurolemma is advantageous for various reasons: tissue can be obtained from various sources and at different developmental stages; ion channels and receptors are present in their native configuration in their proper lipid environment along with appropriate auxiliary subunits; allowing the evaluation of numerous channelpathies caused by neurotoxicants in an ex vivo state...
April 7, 2016: Neurotoxicology
Scott J Burwell, Stephen M Malone, William G Iacono
ERP measures may index genetic risk for psychopathology before disorder onset in adolescence, but little is known about their developmental rank-order stability during this period of significant brain maturation. We studied ERP stability in 48 pairs of identical twins (age 14-16 years) tested 1 year apart. Trial-averaged voltage waveforms were extracted from electroencephalographic recordings from oddball/novelty, go/no-go, and flanker tasks, and 16 amplitude measures were examined. Members of twin pairs were highly similar, whether based on ERP amplitude measures (intraclass correlation [ICC] median = ...
July 2016: Psychophysiology
K Alviña, E Tara, K Khodakhah
The activity of the deep cerebellar nuclei (DCN) neurons conveys the bulk of the output of the cerebellum. To generate these motor signals, DCN neurons integrate synaptic inputs with their own spontaneous activity. We have previously reported that N-type voltage-gated Ca(2+) channels modulate the spontaneous activity of the majority of juvenile DCN neurons in vitro. Specifically, pharmacologically blocking N-type Ca(2+) channels increases their firing rate causing DCN cells to burst. Adult DCN neurons however, behaved differently...
May 13, 2016: Neuroscience
Kyunghee X Kim, Mark A Rutherford
UNLABELLED: Auditory nerve excitation and thus hearing depend on spike-generating ion channels and their placement along the axons of auditory nerve fibers (ANFs). The developmental expression patterns and native axonal locations of voltage-gated ion channels in ANFs are unknown. Therefore, we examined the development of heminodes and nodes of Ranvier in the peripheral axons of type I ANFs in the rat cochlea with immunohistochemistry and confocal microscopy. Nodal structures presumably supporting presensory spiking formed between postnatal days 5 (P5) and P7, including Ankyrin-G, NaV1...
February 17, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Ryoko Fukai, Hirotomo Saitsu, Yoshinori Tsurusaki, Yasunari Sakai, Kazuhiro Haginoya, Kazumasa Takahashi, Monika Weisz Hubshman, Nobuhiko Okamoto, Mitsuko Nakashima, Fumiaki Tanaka, Noriko Miyake, Naomichi Matsumoto
The voltage-gated Kv10.1 potassium channel, also known as ether-a-go-go-related gene 1, encoded by KCNH1 (potassium voltage-gated channel, subfamily H (eag related), member 1) is predominantly expressed in the central nervous system. Recently, de novo missense KCNH1 mutations have been identified in six patients with Zimmermann-Laband syndrome and in four patients with Temple-Baraitser syndrome. These syndromes were historically considered distinct. Here we report three de novo missense KCNH1 mutations in four patients with syndromic developmental delay and epilepsy...
May 2016: Journal of Human Genetics
Derek L Weyhrauch, Dan Ye, Nicole J Boczek, David J Tester, Ralitza H Gavrilova, Marc C Patterson, Eric D Wieben, Michael J Ackerman
BACKGROUND: A 4-year-old boy born at 37 weeks' gestation with intrauterine growth retardation presented with developmental delay with pronounced language and gross motor delay, axial hypotonia, and dynamic hypertonia of the extremities. Investigations including the Minnesota Newborn Screen, thyroid stimulating hormone/thyroxin, and inborn errors of metabolism screening were negative. Cerebral magnetic resonance imaging and spectroscopy were normal. Genetic testing was negative for coagulopathy, Smith-Lemli-Opitz, fragile X, and Prader-Willi/Angelman syndromes...
February 2016: Pediatric Neurology
Yingxiang Li, Linlin Zhang, Tao Qu, Li Li, Guofan Zhang
Genomic and transcriptomic studies have revealed a sophisticated and powerful apoptosis regulation network in oyster, highlighting its adaptation to sessile life in a highly stressful intertidal environment. However, the functional molecular basis of apoptosis remains largely unexplored in oysters. In this study, we focused on a representative apoptotic gene encoding voltage-dependent anion channel 2 (VDAC2), a porin that abounds at the mitochondrial outer membrane. This is the first report on the identification and characterization of a VDAC gene in the Pacific oyster, Crassostrea gigas (CgVDAC2)...
2016: PloS One
Takehiko Inui, Satoru Kobayashi, Yuka Ashikari, Ryo Sato, Wakaba Endo, Mitsugu Uematsu, Hiroshi Oba, Hirotomo Saitsu, Naomichi Matsumoto, Shigeo Kure, Kazuhiro Haginoya
BACKGROUND: Mutations in the elongation factor 1 alpha 2 (EEF1A2) gene have recently been shown to cause severe intellectual disability with early-onset epilepsy. The specific manifestations of mutations in this gene remain unknown. CASE REPORT: We report two cases of severe intellectual disability accompanied by early-onset epilepsy with continuous delta activity evident on electroencephalography. Both cases presented with developmental delay and repetitive myoclonic seizures in early infancy...
May 2016: Brain & Development
Gabriella A Horvath, Michelle Demos, Casper Shyr, Allison Matthews, Linhua Zhang, Simone Race, Sylvia Stockler-Ipsiroglu, Margot I Van Allen, Ogan Mancarci, Lilah Toker, Paul Pavlidis, Colin J Ross, Wyeth W Wasserman, Natalie Trump, Simon Heales, Simon Pope, J Helen Cross, Clara D M van Karnebeek
We describe neurotransmitter abnormalities in two patients with drug-resistant epilepsy resulting from deleterious de novo mutations in sodium channel genes. Whole exome sequencing identified a de novo SCN2A splice-site mutation (c.2379+1G>A, p.Glu717Gly.fs*30) resulting in deletion of exon 14, in a 10-year old male with early onset global developmental delay, intermittent ataxia, autism, hypotonia, epileptic encephalopathy and cerebral/cerebellar atrophy. In the cerebrospinal fluid both homovanillic acid and 5-hydroxyindoleacetic acid were significantly decreased; extensive biochemical and genetic investigations ruled out primary neurotransmitter deficiencies and other known inborn errors of metabolism...
January 2016: Molecular Genetics and Metabolism
Sören Brandenburg, Eric C Arakel, Blanche Schwappach, Stephan E Lehnart
Atrial cardiomyocytes are essential for fluid homeostasis, ventricular filling, and survival, yet their cell biology and physiology are incompletely understood. It has become clear that the cell fate of atrial cardiomyocytes depends significantly on transcription programs that might control thousands of differentially expressed genes. Atrial muscle membranes propagate action potentials and activate myofilament force generation, producing overall faster contractions than ventricular muscles. While atria-specific excitation and contractility depend critically on intracellular Ca(2+) signalling, voltage-dependent L-type Ca(2+) channels and ryanodine receptor Ca(2+) release channels are each expressed at high levels similar to ventricles...
July 2016: Biochimica et Biophysica Acta
Hirotomo Saitsu, Tenpei Akita, Jun Tohyama, Hadassa Goldberg-Stern, Yu Kobayashi, Roni Cohen, Mitsuhiro Kato, Chihiro Ohba, Satoko Miyatake, Yoshinori Tsurusaki, Mitsuko Nakashima, Noriko Miyake, Atsuo Fukuda, Naomichi Matsumoto
The voltage-gated Kv2.1 potassium channel encoded by KCNB1 produces the major delayed rectifier potassium current in pyramidal neurons. Recently, de novo heterozygous missense KCNB1 mutations have been identified in three patients with epileptic encephalopathy and a patient with neurodevelopmental disorder. However, the frequency of KCNB1 mutations in infantile epileptic patients and their effects on neuronal activity are yet unknown. We searched whole exome sequencing data of a total of 437 patients with infantile epilepsy, and found novel de novo heterozygous missense KCNB1 mutations in two patients showing psychomotor developmental delay and severe infantile generalized seizures with high-amplitude spike-and-wave electroencephalogram discharges...
2015: Scientific Reports
Rami Shinnawi, Irit Huber, Leonid Maizels, Naim Shaheen, Amira Gepstein, Gil Arbel, Anke J Tijsen, Lior Gepstein
The advent of the human-induced pluripotent stem cell (hiPSC) technology has transformed biomedical research, providing new tools for human disease modeling, drug development, and regenerative medicine. To fulfill its unique potential in the cardiovascular field, efficient methods should be developed for high-resolution, large-scale, long-term, and serial functional cellular phenotyping of hiPSC-derived cardiomyocytes (hiPSC-CMs). To achieve this goal, we combined the hiPSC technology with genetically encoded voltage (ArcLight) and calcium (GCaMP5G) fluorescent indicators...
October 13, 2015: Stem Cell Reports
Katherine B Howell, Jacinta M McMahon, Gemma L Carvill, Dimira Tambunan, Mark T Mackay, Victoria Rodriguez-Casero, Richard Webster, Damian Clark, Jeremy L Freeman, Sophie Calvert, Heather E Olson, Simone Mandelstam, Annapurna Poduri, Heather C Mefford, A Simon Harvey, Ingrid E Scheffer
OBJECTIVE: De novo SCN2A mutations have recently been associated with severe infantile-onset epilepsies. Herein, we define the phenotypic spectrum of SCN2A encephalopathy. METHODS: Twelve patients with an SCN2A epileptic encephalopathy underwent electroclinical phenotyping. RESULTS: Patients were aged 0.7 to 22 years; 3 were deceased. Seizures commenced on day 1-4 in 8, week 2-6 in 2, and after 1 year in 2. Characteristic features included clusters of brief focal seizures with multiple hourly (9 patients), multiple daily (2), or multiple weekly (1) seizures, peaking at maximal frequency within 3 months of onset...
September 15, 2015: Neurology
Na Li, Yongmei Li, Qinqin Gao, Dawei Li, Jiaqi Tang, Miao Sun, Pengjie Zhang, Bailin Liu, Caiping Mao, Zhice Xu
Caffeine modifies vascular/cardiac contractility. Embryonic exposure to caffeine altered cardiac functions in offspring. This study determined chronic influence of prenatal caffeine on vessel functions in offspring. Pregnant Sprague-Dawley rats (5-month-old) were exposed to high dose of caffeine, their offspring (5-month-old) were tested for vascular functions in mesenteric arteries (MA) and ion channel activities in smooth muscle cells. Prenatal exposure to caffeine increased pressor responses and vasoconstrictions to phenylephrine, accompanied by enhanced membrane depolarization...
2015: Scientific Reports
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