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https://www.readbyqxmd.com/read/29053689/whole-cell-currents-induced-by-puff-application-of-gaba-in-brain-slices
#1
Yangjian Feng, Binliang Tang, Ming Chen, Li Yang
Pharmacological administration is commonly used when conducting whole-cell patch-clamp recording in brain slices. One of the best methods of drug application during electrophysiological recording is the puff technique, which can be used to study the effect of pharmacological reagents on neuronal activities in brain slices. The greatest advantage of puff application is that the drug concentration around the recording site increases rapidly, thus preventing desensitization of membrane receptors. Successful use of puff application involves careful attention to the following elements: the concentration of the drug, the parameters of the puff micropipette, the distance between the tip of a puff micropipette and the neuron recorded, and the duration and pressure driving the puff (pounds per square inch, psi)...
October 12, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/29050392/clinical-spectrum-and-genotype-phenotype-associations-of-kcna2-related-encephalopathies
#2
Silvia Masnada, Ulrike B S Hedrich, Elena Gardella, Julian Schubert, Charu Kaiwar, Eric W Klee, Brendan C Lanpher, Ralitza H Gavrilova, Matthis Synofzik, Thomas Bast, Kathleen Gorman, Mary D King, Nicholas M Allen, Judith Conroy, Bruria Ben Zeev, Michal Tzadok, Christian Korff, Fanny Dubois, Keri Ramsey, Vinodh Narayanan, Jose M Serratosa, Beatriz G Giraldez, Ingo Helbig, Eric Marsh, Margaret O'Brien, Christina A Bergqvist, Adrian Binelli, Brenda Porter, Eduardo Zaeyen, Dafne D Horovitz, Markus Wolff, Dragan Marjanovic, Hande S Caglayan, Mutluay Arslan, Sergio D J Pena, Sanjay M Sisodiya, Simona Balestrini, Steffen Syrbe, Pierangelo Veggiotti, Johannes R Lemke, Rikke S Møller, Holger Lerche, Guido Rubboli
Recently, de novo mutations in the gene KCNA2, causing either a dominant-negative loss-of-function or a gain-of-function of the voltage-gated K+ channel Kv1.2, were described to cause a new molecular entity within the epileptic encephalopathies. Here, we report a cohort of 23 patients (eight previously described) with epileptic encephalopathy carrying either novel or known KCNA2 mutations, with the aim to detail the clinical phenotype associated with each of them, to characterize the functional effects of the newly identified mutations, and to assess genotype-phenotype associations...
September 1, 2017: Brain: a Journal of Neurology
https://www.readbyqxmd.com/read/29046639/neonatal-colonic-inflammation-increases-spinal-transmission-and-cystathionine-%C3%AE-synthetase-expression-in-spinal-dorsal-horn-of-rats-with-visceral-hypersensitivity
#3
Liting Zhao, Ying Xiao, Rui-Xia Weng, Xuelian Liu, Ping-An Zhang, Chuang-Ying Hu, Shan P Yu, Guang-Yin Xu
Irritable bowel syndrome (IBS) is a common gastrointestinal disorder characterized by chronic abdominal pain and alteration of bowel movements. The pathogenesis of visceral hypersensitivity in IBS patients remains largely unknown. Hydrogen sulfide (H2S) is reported to play an important role in development of visceral hyperalgesia. However, the role of H2S at spinal dorsal horn level remains elusive in visceral hypersensitivity. The aim of this study is designed to investigate how H2S takes part in visceral hypersensitivity of adult rats with neonatal colonic inflammation (NCI)...
2017: Frontiers in Pharmacology
https://www.readbyqxmd.com/read/29046423/the-intrinsic-physiology-of-inhibitory-neurons-changes-over-auditory-development
#4
Briana J Carroll, Richard Bertram, Richard L Hyson
During auditory development, changes in membrane properties promote the ability of excitatory neurons in the brainstem to code aspects of sound, including the level and timing of a stimulus. Some of these changes coincide with hearing onset, suggesting that sound-driven neural activity produces developmental plasticity of ion channel expression. While it is known that the coding properties of excitatory neurons are modulated by inhibition in the mature system, it is unknown whether there are also developmental changes in the membrane properties of brainstem inhibitory neurons...
October 18, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/29045640/action-potential-contour-contributes-to-species-differences-in-repolarization-response-to-%C3%AE-adrenergic-stimulation
#5
Luca Sala, Bence Hegyi, Chiara Bartolucci, Claudia Altomare, Marcella Rocchetti, Krisztina Váczi, Gaspare Mostacciuolo, Norbert Szentandrássy, Stefano Severi, Péter Pál Nánási, Antonio Zaza
Aim: Repolarization response to β-adrenergic (β-AR) stimulation differs between guinea-pig and canine myocytes and, within the latter, between myocardial layers. Correlative analysis suggests that this may be due to differences in action potential (AP) contour. Here we tested whether AP contour may set the response of current and of repolarization to β-AR stimulation (10 nM isoproterenol, ISO). Methods and Results: The responses of AP and current to ISO were measured under I-clamp and "AP-clamp" in guinea-pig (GP), dog epicardial (DEPI) and dog subendocardial (DENDO) myocytes...
October 17, 2017: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
https://www.readbyqxmd.com/read/29037815/an-operating-principle-of-the-turtle-utricle-to-detect-wide-dynamic-range
#6
Jong-Hoon Nam
The utricle encodes both static information such as head orientation, and dynamic information such as vibrations. It is not well understood how the utricle can encode both static and dynamic information for a wide dynamic range (from <0.05 to >2 times the gravitational acceleration; from DC to > 1000 Hz vibrations). Using computational models of the hair cells in the turtle utricle, this study presents an explanation on how the turtle utricle encodes stimulations over such a wide dynamic range. Two hair bundles were modeled using the finite element method-one representing the striolar hair cell (Cell S), and the other representing the medial extrastriolar hair cell (Cell E)...
October 9, 2017: Hearing Research
https://www.readbyqxmd.com/read/29035465/enhanced-specificity-of-braf-v600e-genotyping-using-wild-type-blocker-coupled-with-internal-competitive-reference-in-a-single-tube
#7
Jia Peng, Kun Wei, Shu Yu, Xiang Yang, Xiang Zhao, Yu Liu, Xiao-Yan Zhu, Na Zhao, Qing Huang, Wei-Ling Fu
BACKGROUND: Mutations in the BRAF gene have been strongly associated with failure in cancer treatment using epidermal growth factor receptor (EGFR) antibodies. To better diagnose and assess the prognosis of cancer patients, mutation screening of the BRAFV600E gene should be performed prior to clinical anti-tumor drug therapy to avoid ineffective treatment. METHODS: In our previous study, we developed a real-time wild-type blocking PCR (WTB-PCR), which can amplify the mutant allele at high efficiency while simultaneously inhibiting the amplification of wild-type alleles...
October 1, 2017: Clinical Laboratory
https://www.readbyqxmd.com/read/29034580/selective-inhibition-of-trpm2-channel-by-two-novel-synthesized-adpr-analogues
#8
Xiao Luo, Meng Li, Kaiyu Zhan, Wei Yang, Lihe Zhang, KeWei Wang, Peilin Yu, Liangren Zhang
Transient receptor potential melastatin-2 (TRPM2) channel critical for monitoring internal body temperature is implicated in the pathological processes such as neurodegeneration. However, lacking selective and potent TRPM2 inhibitors impedes investigation and validation of the channel as a drug target. To discover novel and selective TRPM2 inhibitors, a series of adenosine 5'-diphosphoribose (ADPR) analogues were synthesized and their activities and selectivity were evaluated. Whole-cell patch clamp recordings were employed for screen and evaluation of synthesized compounds...
October 15, 2017: Chemical Biology & Drug Design
https://www.readbyqxmd.com/read/29032008/3-iodothyroacetic-acid-ta1-a-by-product-of-thyroid-hormone-metabolism-reduces-the-hypnotic-effect-of-ethanol-without-interacting-at-gaba-a-receptors
#9
Annunziatina Laurino, Elisa Landucci, Francesco Resta, Gaetano De Siena, Rosanna Matucci, Alessio Masi, Laura Raimondi
3-iodothyroacetic acid (TA1) is among the by-products of thyroid hormone metabolism suspected to mediate the non-genomic effects of the hormone (T3). We aim to investigate whether TA1 systemically administered to mice stimulated mice wakefulness, an effect already described for T3 and for another T3 metabolite (i.e. 3-iodothryonamine; T1AM), and whether TA1 interacted at GABA-A receptors (GABA-AR). Mice were pre-treated with either saline (vehicle) or TA1 (1.32, 4 and 11 μg/kg) and, after 10 min, they received ethanol (3...
October 11, 2017: Neurochemistry International
https://www.readbyqxmd.com/read/29031852/inhibition-of-cdk5-rejuvenates-inhibitory-circuits-and-restores-experience-dependent-plasticity-in-adult-visual-cortex
#10
Yue Li, Laijian Wang, Xinxin Zhang, Mengyao Huang, Sitong Li, Xinxing Wang, Lin Chen, Bin Jiang, Yupeng Yang
Cyclin-dependent kinase 5 (Cdk5) acts as an essential modulator for neural development and neurological disorders. Here we show that Cdk5 plays a pivotal role in modulating GABAergic signaling and the maturation of visual system. In adult mouse primary visual cortex, Cdk5 formed complex with the GABA synthetic enzyme glutamate decarboxylase GAD67, but not with GAD65. In addition to enhancement in the surface level of NR2B-containing NMDA receptors, inhibition of Cdk5 reduced the protein levels of GADs and Otx2, while leaving intact the expression of vesicular GABA transporter and subunits of GABAA or AMPA receptors...
October 12, 2017: Neuropharmacology
https://www.readbyqxmd.com/read/29030712/calculating-the-consequences-of-left-shifted-nav-channel-activity-in-sick-excitable-cells
#11
Bela Joos, Benjamin M Barlow, Catherine E Morris
Two features common to diverse sick excitable cells are "leaky" Nav channels and bleb damage-damaged membranes. The bleb damage, we have argued, causes a channel kinetics based "leakiness." Recombinant (node of Ranvier type) Nav1.6 channels voltage-clamped in mechanically-blebbed cell-attached patches undergo a damage intensity dependent kinetic change. Specifically, they experience a coupled hyperpolarizing (left) shift of the activation and inactivation processes. The biophysical observations on Nav1.6 currents formed the basis of Nav-Coupled Left Shift (Nav-CLS) theory...
October 14, 2017: Handbook of Experimental Pharmacology
https://www.readbyqxmd.com/read/29030575/adolescent-ethanol-exposure-enhances-nmda-receptor-mediated-currents-in-hippocampal-neurons-reversal-by-gabapentin
#12
H S Swartzwelder, Maeng-Hee Park, Shawn Acheson
Adolescent intermittent ethanol (AIE) exposure compromises neural function into adulthood. We have reported that astrocyte-secreted thrombospondins, and their target neuronal receptors (α2δ-1) are upregulated in the hippocampus in adulthood after AIE, suggesting aberrant excitatory synaptogenesis and hyperexcitability in memory-related circuits. Gabapentin antagonizes the interaction of thrombospondins (TSPs) with the α2δ-1 receptor, and thus may reverse or ameliorate the effects of AIE on hippocampal function...
October 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29030398/on-the-effect-of-hyperaldosteronism-inducing-mutations-in-na-k-pumps
#13
Dylan J Meyer, Craig Gatto, Pablo Artigas
Primary aldosteronism, a condition in which too much aldosterone is produced and that leads to hypertension, is often initiated by an aldosterone-producing adenoma within the zona glomerulosa of the adrenal cortex. Somatic mutations of ATP1A1, encoding the Na/K pump α1 subunit, have been found in these adenomas. It has been proposed that a passive inward current transported by several of these mutant pumps is a "gain-of-function" activity that produces membrane depolarization and concomitant increases in aldosterone production...
October 13, 2017: Journal of General Physiology
https://www.readbyqxmd.com/read/29029290/nmda-receptor-mediated-ca2-influx-in-the-absence-of-mg2-block-disrupts-rest-activity-rhythms-in-drosophila
#14
Qian Song, Ge Feng, Jiaxing Zhang, Xuechun Xia, Min Ji, Lei Lv, Yong Ping
Introduction: The correlated activation of pre- and postsynaptic neurons is essential for the NMDA receptor-mediated Ca2+ influx by removing Mg2+ from block site and NMDA receptors have been implicated in phase resetting of circadian clocks. So we assessed rest:activity rhythms in Mg2+ block defective animals. Methods: Using Drosophila locomotor monitoring system, we checked circadian rest:activity rhythms of different mutants under constant darkness (DD) and light:dark (LD) conditions...
October 3, 2017: Sleep
https://www.readbyqxmd.com/read/29027245/epac-induced-ryanodine-receptor-type-2-activation-inhibits-sodium-currents-in-atrial-and-ventricular-murine-cardiomyocytes
#15
Haseeb Valli, Shiraz Ahmad, Sujan Sriharan, Lydia D Dean, Andrew A Grace, Kamalan Jeevaratnam, Hugh R Matthews, Christopher L-H Huang
Acute RyR2 activation by exchange protein directly activated by cAMP (Epac) reversibly perturbs myocyte Ca(2+) homeostasis, slows myocardial action potential conduction, and exerts pro-arrhythmic effects. Loose patch-clamp studies, preserving in vivo extracellular and intracellular conditions, investigated Na(+) current in intact cardiomyocytes in murine atrial and ventricular preparations following Epac activation. Depolarising steps to varying test voltages activated typical voltage-dependent Na(+) currents...
October 12, 2017: Clinical and Experimental Pharmacology & Physiology
https://www.readbyqxmd.com/read/29023772/negative-modulation-of-the-gabaa-%C3%AF-1-receptor-function-by-l-cysteine
#16
Andrea N Beltrán González, Florencia Vicentini, Daniel J Calvo
L-Cysteine is an endogenous Sulphur containing amino acid with multiple and varied roles in the central nervous system, including neuroprotection and the maintenance of the redox balance. However, it was also suggested as an excitotoxic agent implicated in the pathogenesis of neurological disorders such as Parkinson's and Alzheimer's disease. L-Cysteine can modulate the activity of ionic channels, including voltage-gated calcium channels and glutamatergic NMDA receptors, whereas its effects on GABAergic neurotransmission had not been studied before...
October 10, 2017: Journal of Neurochemistry
https://www.readbyqxmd.com/read/29019677/scalaradial-is-a-potent-inhibitor-of-transient-receptor-potential-melastatin-2-trpm2-ion-channels
#17
John G Starkus, Peter Poerzgen, Kristine Layugan, Kelly Galbraith Kawabata, Jun-Ichi Goto, Sayuri Suzuki, George Myers, Michelle Kelly, Reinhold Penner, Andrea Fleig, F David Horgen
TRPM2 is a Ca(2+)-permeable, nonselective cation channel that plays a role in oxidant-induced cell death, insulin secretion, and cytokine release. Few TRPM2 inhibitors have been reported, which hampers the validation of TRPM2 as a drug target. While screening our in-house marine-derived chemical library, we identified scalaradial and 12-deacetylscalaradial as the active components within an extract of an undescribed species of Cacospongia (class Demospongiae, family Thorectidae) that strongly inhibited TRPM2-mediated Ca(2+) influx in TRPM2-overexpressing HEK293 cells...
October 11, 2017: Journal of Natural Products
https://www.readbyqxmd.com/read/29018970/andersen-s-syndrome-mutants-produce-a-knockdown-of-inwardly-rectifying-k-channel-in-mouse-skeletal-muscle-in-vivo
#18
Dina Simkin, Gaëlle Robin, Serena Giuliano, Ana Vukolic, Pamela Moceri, Nicolas Guy, Kay-Dietrich Wagner, Alain Lacampagne, Bruno Allard, Saïd Bendahhou
Andersen's syndrome (AS) is a rare autosomal disorder that has been defined by the triad of periodic paralysis, cardiac arrhythmia, and developmental anomalies. AS has been directly linked to over 40 different autosomal dominant negative loss-of-function mutations in the KCNJ2 gene, encoding for the tetrameric strong inward rectifying K(+) channel KIR2.1. While KIR2.1 channels have been suggested to contribute to setting the resting membrane potential (RMP) and to control the duration of the action potential (AP) in skeletal and cardiac muscle, the mechanism by which AS mutations produce such complex pathophysiological symptoms is poorly understood...
October 10, 2017: Cell and Tissue Research
https://www.readbyqxmd.com/read/29017447/characterization-of-a-novel-kcnj2-sequence-variant-detected-in-andersen-tawil-syndrome-patients
#19
Stefanie Scheiper, Brigitte Hertel, Britt-Maria Beckmann, Stefan Kääb, Gerhard Thiel, Silke Kauferstein
BACKGROUND: Mutations in the KCNJ2 gene encoding the ion channel Kir2.1 have been linked to the Andersen-Tawil syndrome (ATS). Molecular genetic screening performed in a family exhibiting clinical ATS phenotypes unmasked a novel sequence variant (c.434A > G, p.Y145C) in this gene. The aim of this study was to investigate the effect of this variant on Kir2.1 ion channel functionality. METHODS: Mutant as well as wild type GFP tagged Kir2.1 channels were expressed in HEK293 cells...
October 10, 2017: BMC Medical Genetics
https://www.readbyqxmd.com/read/29016681/heterodimerization-of-two-pore-domain-k-channel-task1-and-talk2-in-living-heterologous-expression-systems
#20
Yoshiaki Suzuki, Kanako Tsutsumi, Tatsuya Miyamoto, Hisao Yamamura, Yuji Imaizumi
Two-pore-domain K+ (K2P) channels sense a wide variety of stimuli such as mechanical stress, inhalational anesthetics, and changes in extracellular pH or temperature. The K2P channel activity forms a background K+ current and, thereby, contributes to resting membrane potentials. Six subfamilies including fifteen subtypes of K2P channels have been identified. Each K2P channel molecule with two pores consists of a homodimer of each subtype. In addition, a few heterodimers mainly within the same subfamilies have been found recently...
2017: PloS One
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