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Whole cell patch clamp

Thomas Pannicke, T Ivo Chao, Miriam Reisenhofer, Mike Francke, Andreas Reichenbach
Müller cells are the dominant macroglial cells in the retina of all vertebrates. They fulfill a variety of functions important for retinal physiology, among them spatial buffering of K(+) ions and uptake of glutamate and other neurotransmitters. To this end, Müller cells express inwardly rectifying K(+) channels and electrogenic glutamate transporters. Moreover, a lot of voltage- and ligand-gated ion channels, aquaporin water channels, and electrogenic transporters are expressed in Müller cells, some of them in a species-specific manner...
October 21, 2016: Glia
Marijn Bart Martens, Monica Frega, Jessica Classen, Lisa Epping, Elske Bijvank, Marco Benevento, Hans van Bokhoven, Paul Tiesinga, Dirk Schubert, Nael Nadif Kasri
Heterozygous mutations or deletions in the human Euchromatin histone methyltransferase 1 (EHMT1) gene cause Kleefstra syndrome, a neurodevelopmental disorder that is characterized by autistic-like features and severe intellectual disability (ID). Neurodevelopmental disorders including ID and autism may be related to deficits in activity-dependent wiring of brain circuits during development. Although Kleefstra syndrome has been associated with dendritic and synaptic defects in mice and Drosophila, little is known about the role of EHMT1 in the development of cortical neuronal networks...
October 21, 2016: Scientific Reports
Jay S Naik, Jessica M Osmond, Benjimen R Walker, Nancy L Kanagy
Hydrogen sulfide (H2S) is a recently described gaseous vasodilator produced within the vasculature by the enzymes cystathionine γ-lyase and 3-mercaptopyruvate sulfurtansferase. Previous data demonstrate that endothelial cells (EC) are the source of endogenous H2S production and are required for H2S-induced dilation. However, the signal transduction pathway activated by H2S within EC has not been elucidated. TRPV4 and large conductance Ca(2+)-activated K channels (BK channels) are expressed in EC. H2S-induced dilation is inhibited by luminal administration of iberiotoxin and disruption of the endothelium...
October 7, 2016: American Journal of Physiology. Heart and Circulatory Physiology
Juexin Wang, Dingding Shen, Geqing Xia, Wangzhen Shen, Robert L Macdonald, Dong Xu, Jing-Qiong Kang
Mutations in GABAA receptor subunit genes are frequently associated with epilepsy, and nonsense mutations in GABRG2 are associated with several epilepsy syndromes including childhood absence epilepsy, generalized tonic clonic seizures and the epileptic encephalopathy, Dravet syndrome. The molecular basis for the phenotypic heterogeneity of mutations is unclear. Here we focused on three nonsense mutations in GABRG2 (GABRG2(R136*), GABRG2(Q390*) and GABRG2(W429*)) associated with epilepsies of different severities...
October 20, 2016: Scientific Reports
Takehito Kondo, Ichiro Hisatome, Shouichi Yoshimura, Endang Mahati, Tomomi Notsu, Peili Li, Kazuhiko Iitsuka, Masaru Kato, Kazuyoshi Ogura, Junichiro Miake, Takeshi Aiba, Wataru Shimizu, Yasutaka Kurata, Shinji Sakata, Naoe Nakasone, Haruaki Ninomiya, Akira Nakai, Katsumi Higaki, Yasushi Kawata, Yasuaki Shirayoshi, Akio Yoshida, Kazuhiro Yamamoto
BACKGROUND: The human ether-a-go-go-related gene (HERG) encodes the α-subunit of rapidly activating delayed-rectifier potassium channels. Mutations in this gene cause long QT syndrome type 2 (LQT2). In most cases, mutations reduce the stability of the channel protein, which can be restored by heat shock (HS). METHODS: We identified the novel mutant A78T-HERG in a patient with LQT2. The purpose of the current study was to characterize this mutant protein and test whether HS and heat shock factors (HSFs) could stabilize the mutant protein...
October 2016: Journal of Arrhythmia
Can-Zhao Liu, Xiang-Yu Li, Ren-Hong Du, Min Gao, Ming-Ming Ma, Fei-Ya Li, Er-Wen Huang, Hong-Shuo Sun, Guan-Lei Wang, Yong-Yuan Guan
BACKGROUND: Previous research has demonstrated that ClC-3 is responsible for volume-regulated Cl(-)current (ICl.vol) in vascular smooth muscle cells (VSMCs). However, it is still not clear whether and how ClC-3 is transported to cell membranes, resulting in alteration ofICl.vol.Methods and Results:Volume-regulated chloride current (ICl.vol) was recorded by whole-cell patch clamp recording, and Western blotting and co-immunoprecipitation were performed to examine protein expression and protein-protein interaction...
October 19, 2016: Circulation Journal: Official Journal of the Japanese Circulation Society
In-Sik Kang, Jin-Hwa Cho, In-Sun Choi, Do-Yeon Kim, Il-Sung Jang
Cell bodies of trigeminal mesencephalic nucleus (Vmes) neurons are located within the central nervous system, and therefore, peripheral as well as central acidosis can modulate the excitability of Vmes neurons. Here, we report the effect of acidic pH on voltage-gated Na channels in acutely isolated rat Vmes neurons using a conventional whole-cell patch clamp technique. Acidic pH (pH 6.0) slightly but significantly shifted both the activation and steady-state fast inactivation relationships toward depolarized potentials...
October 14, 2016: Neuroreport
Yun Ling, Zhuang-Li Hu, Qing-Li Meng, Peng Fang, Hai-Xia Liu
Our previous study found that some trigeminal ganglion (TG) nerve endings in the inner walls of rat anterior chambers were mechanosensitive, and transient receptor potential ankyrin 1 (TRPA1) was an essential mechanosensitive channel in the membrane. To address the effect of cannabinoids on the mechanosensitive TG nerve endings in the inner walls of anterior chambers of rat eye, we investigated the effect of the (R)-(+)-WIN55, 212-2 mesylate salt (WIN), a synthetic cannabinoid on their cell bodies in vitro...
October 2016: Journal of Huazhong University of Science and Technology. Medical Sciences
Li-Jie Wang, Wei-Dong Liu, Liang Zhang, Ke-Tao Ma, Lei Zhao, Wen-Yan Shi, Wen-Wen Zhang, Ying-Zi Wang, Li Li, Jun-Qiang Si
Niflumic acid (NFA) is a novel gap junction (GJ) inhibitor. The aim of the present study was to investigate the effect of NFA on GJ communication and the expression of connexin (Cx) in vascular smooth muscle cells (VSMCs) of mesenteric arterioles of spontaneously hypertensive rats (SHR). Whole‑cell patch clamp recording demonstrated that NFA at 1x10‑4 M significantly inhibited the inward current and its effect was reversible. The time for charging and discharging of cell membrane capacitance (Cinput) reduced from 9...
September 26, 2016: Molecular Medicine Reports
Manuel Sánchez, Lorena Suárez, Begoña Cantabrana, Javier Bordallo
Estrogens facilitate prolactin (PRL) secretion acting on pituitary cells. In GH3 cells, estradiol induces acute action potentials and oscillations of intracellular Ca(2+) associated with the secretagogue function. Estradiol modulates several ion channels which may affect the action potential rate and the release of PRL in lactotroph cells, which might depend on its concentration. The aims were to characterize the acute effect of supraphysiological concentrations of estradiol on Ca(2+) and noninactivating K(+) currents and measure the effect on the spontaneous action potentials and PRL release in the somatolactotroph cell line, GH3...
October 17, 2016: Naunyn-Schmiedeberg's Archives of Pharmacology
Keisuke Kaneko, Yuko Koyanagi, Yoshiyuki Oi, Masayuki Kobayashi
Propofol is a major intravenous anesthetic that facilitates GABAA receptor-mediated inhibitory synaptic currents and modulates Ih, K(+), and voltage-gated Na(+) currents. This propofol-induced modulation of ionic currents changes intrinsic membrane properties and repetitive spike firing in cortical pyramidal neurons. However, it has been unknown whether propofol modulates these electrophysiological properties in GABAergic neurons, which express these ion channels at different levels. This study examined whether pyramidal and GABAergic neuronal properties are differentially modulated by propofol in the rat insular cortical slice preparation...
October 13, 2016: Neuroscience
Nan Zhang, Shengchang Yang, Chang Wang, Jianghua Zhang, Lifang Huo, Yiru Cheng, Chuan Wang, Zhanfeng Jia, Leiming Ren, Lin Kang, Wei Zhang
Alzheimer's disease (AD) and type II diabetes mellitus (DM2) are the most common aging-related diseases and are characterized by β-amyloid and amylin accumulation, respectively. Multiple studies have indicated a strong correlation between these two diseases. Amylin oligomerization in the brain appears to be a novel risk factor for developing AD. Although amylin aggregation has been demonstrated to induce cytotoxicity in neurons through altering Ca(2+) homeostasis, the underlying mechanisms have not been fully explored...
October 12, 2016: Neuropharmacology
Nicola Forte, Lucian Medrihan, Beatrice Cappetti, Pietro Baldelli, Fabio Benfenati
OBJECTIVE: The inhibition of glycolysis exerts potent antiseizure effects, as demonstrated by the efficacy of ketogenic and low-glucose/nonketogenic diets in the treatment of drug-resistant epilepsy. ATP-sensitive potassium (KATP ) channels have been initially identified as the main determinant of the reduction of neuronal hyperexcitability. However, a plethora of other mechanisms have been proposed. Herein, we report the ability of 2-deoxy-d-glucose (2-DG), a glucose analog that inhibits glycolytic enzymes, of potentiating γ-aminobutyric acid (GABA)ergic tonic inhibition via neurosteroid-mediated activation of extrasynaptic GABAA receptors...
October 13, 2016: Epilepsia
Edyta K Bichler, Courtney C Elder, Paul S García
Antibiotics are used in the treatment and prevention of bacterial infections, but effects on neuron excitability have been documented. A recent study demonstrated that clarithromycin alleviates daytime sleepiness in hypersomnia patients (Trotti et al. 2014). To explore the potential application of clarithromycin as a stimulant, we performed whole cell patch clamp recordings in rat pyramidal cells from the CA3 region of hippocampus. In the presence of the antibiotic, rheobase current was reduced by 50%, F-I relationship (number of action potentials as a function of injected current) was shifted to the left, and the resting membrane potential was more depolarized...
October 12, 2016: Journal of Neurophysiology
Alex S Mauss, Alexander Borst
Drosophila has emerged as an important model organism for the study of the neural basis of behavior. Its main asset is the experimental accessibility of identified neurons by genetic manipulation and physiological recordings. Drosophila therefore offers the opportunity to reach an integrative understanding of the development and neural underpinnings of behavior at all processing stages, from sensing to motor control, in a single species. Here, we will provide an account of the procedures involved in recording the electrical potential of individual neurons in the visual system of adult Drosophila using the whole-cell patch-clamp method...
2016: Methods in Molecular Biology
Eiko Yokota, Yuko Koyanagi, Kiyofumi Yamamoto, Yoshiyuki Oi, Noriaki Koshikawa, Masayuki Kobayashi
The insular cortex (IC) plays a principal role in the regulation of pain processing. Although opioidergic agonists depress cortical excitatory synaptic transmission, little is known about opioidergic roles in inhibitory synaptic transmission. In the IC, the opioid receptors differentially regulate the excitatory propagation: agonists of the mu (MOR), delta (DOR), and kappa (KOR) exhibit suppressive, facilitative, and little effects, respectively. Thus, we aimed to examine the effects of opioid receptor agonists on unitary inhibitory postsynaptic currents (uIPSCs) in the IC...
October 7, 2016: Neuroscience
Sophie Le Page, Marjorie Niro, Jérémy Fauconnier, Laura Cellier, Sophie Tamareille, Abdallah Gharib, Arnaud Chevrollier, Laurent Loufrani, Céline Grenier, Rima Kamel, Emmanuelle Sarzi, Alain Lacampagne, Michel Ovize, Daniel Henrion, Pascal Reynier, Guy Lenaers, Delphine Mirebeau-Prunier, Fabrice Prunier
BACKGROUND: Recent data suggests the involvement of mitochondrial dynamics in cardiac ischemia/reperfusion (I/R) injuries. Whilst excessive mitochondrial fission has been described as detrimental, the role of fusion proteins in this context remains uncertain. OBJECTIVES: To investigate whether Opa1 (protein involved in mitochondrial inner-membrane fusion) deficiency affects I/R injuries. METHODS AND RESULTS: We examined mice exhibiting Opa1delTTAG mutations (Opa1+/-), showing 70% Opa1 protein expression in the myocardium as compared to their wild-type (WT) littermates...
2016: PloS One
Sean D Boothe, Jackson D Myers, Seokwon Pok, Junping Sun, Yutao Xi, Raymond M Nieto, Jie Cheng, Jeffrey G Jacot
The stiffness of myocardial tissue changes significantly at birth and during neonatal development, concurrent with significant changes in contractile and electrical maturation of cardiomyocytes. Previous studies by our group have shown that cardiomyocytes generate maximum contractile force when cultured on a substrate with a stiffness approximating native cardiac tissue. However, effects of substrate stiffness on the electrophysiology and ion currents in cardiomyocytes have not been fully characterized. In this study, neonatal rat ventricular myocytes were cultured on the surface of flat polyacrylamide hydrogels with elastic moduli ranging from 1 to 25 kPa...
October 8, 2016: Cell Biochemistry and Biophysics
M J Skelly, O J Ariwodola, J L Weiner
Inappropriate fear memory formation is symptomatic of many psychopathologies, and delineating the neurobiology of non-pathological fear learning may provide critical insight into treating these disorders. Fear memory formation is associated with decreased inhibitory signaling in the basolateral amygdala (BLA), and disrupted noradrenergic signaling may contribute to this decrease. BLA noradrenergic neurotransmission has been implicated in fear memory formation, and distinct adrenoreceptor (AR) subtypes modulate excitatory and inhibitory neurotransmission in this region...
October 5, 2016: Neuropharmacology
Antonia Di Mola, Elena Gatta, Carmen Petronzi, Aroldo Cupello, Paolo De Caprariis, Mauro Robello, Antonio Massa, Rosanna Filosa
A focused N-substituted 3-(2-piperazin-1-yl-2-oxoethyl)-2-(pyridin-2-yl)iso-indolin-1-ones small library was synthesized for modulation of GABA-A receptor function and compared to Zopiclone for the ability to increase GABA-activated chloride currents. All compounds were tested for their effects on GABA-activated chloride currents in rat cerebellar granule cells by use of the whole-cell patch clamp technique. Electrophysiological studies on cultured cerebellar granule cells revealed 3-[2-(4-methylpiperazin-1-yl)-2-oxoethyl]-2-(5-nitropyridin-2-yl)iso-indolin-1-one (Id) as a partial agonist displaying 34% increase of the 10μM GABA evoked peak chloride currents, antagonized by flumazenil...
September 15, 2016: Bioorganic & Medicinal Chemistry Letters
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