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https://www.readbyqxmd.com/read/28808726/polarization-transfer-efficiency-in-phip-experiments
#1
M Emondts, J F P Colell, B Blümich, P P M Schleker
Parahydrogen induced polarization (PHIP) is a hyperpolarization method for NMR signal enhancement with applications in spectroscopy and imaging. Although parahydrogen can be easily enriched up to nearly 95%, the polarization detected on the hydrogenated substrate is substantially lower, where numerous loss mechanisms between the start of the hydrogenation reaction and detection affect polarization levels. The quality of PHIP systems is commonly determined by stating either the polarization degree or the enhancement factor of the product at the time of detection...
August 15, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28803659/seizing-control-of-kcc2-a-new-therapeutic-target-for-epilepsy
#2
REVIEW
Yvonne E Moore, Matt R Kelley, Nicholas J Brandon, Tarek Z Deeb, Stephen J Moss
Deficits in GABAergic inhibition result in the abnormal neuronal activation and synchronization that underlies seizures. However, the molecular mechanisms responsible for transforming a normal brain into an epileptic one remain largely unknown. Hyperpolarizing inhibition mediated by type A GABA (GABAA) receptors is dependent on chloride extrusion by the neuron-specific type 2K(+)-Cl(-) cotransporter (KCC2). Loss-of-function mutations in KCC2 are a known cause of infantile epilepsy in humans and KCC2 dysfunction is present in patients with both idiopathic and acquired epilepsy...
August 10, 2017: Trends in Neurosciences
https://www.readbyqxmd.com/read/28801916/adenosine-and-dopamine-oppositely-modulate-a-hyperpolarization-activated-current-ih-in-chemosensory-neurons-of-the-rat-carotid-body-in-co-culture
#3
Min Zhang, Cathy Vollmer, Colin A Nurse
Adenosine and dopamine (DA) act as neurotransmitters or neuromodulators at the carotid body (CB) chemosensory synapse, however, their mechanisms of action are not fully understood. Using a functional co-culture model of rat CB chemoreceptor (type I) cell clusters and juxtaposed afferent petrosal neurons (PNs), we tested the hypothesis that adenosine and DA act postsynaptically to modulate a hyperpolarization-activated, cyclic nucleotide-gated (HCN) cation current (Ih ). In whole-cell recordings from hypoxia-responsive PNs, cAMP mimetics enhanced Ih whereas the HCN blocker ZD7288 (2 μm) reversibly inhibited Ih ...
August 12, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28801662/nanometer-size-silicon-particles-for-hyperpolarized-mri
#4
Grzegorz Kwiatkowski, Fabian Jähnig, Jonas Steinhauser, Patrick Wespi, Matthias Ernst, Sebastian Kozerke
Hyperpolarized silicon particles have been shown to exhibit long spin-lattice relaxation times at room temperature, making them interesting as novel MRI probes. Demonstrations of hyperpolarized silicon particle imaging have focused on large micron size particles (average particle size (APS) = 2.2 μm) as they have, to date, demonstrated much larger polarizations than nanoparticles. We show that also much smaller silicon-29 particles (APS = 55 ± 12 nm) can be hyperpolarized with superior properties...
August 11, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28800409/cytotoxic-effects-of-the-proton-pump-inhibitor-omeprazole-on-the-non-target-marine-microalga-tetraselmis-suecica
#5
Marta Seoane, Marta Esperanza, Ángeles Cid
Omeprazole (OMP) is one of the most commonly used drugs for the treatment of gastro-intestinal disorders. Although it is daily consumed in high quantities and commonly detected in waters worldwide, relatively little is known about its ecotoxicity. The aim of this study was to evaluate the potential acute toxicity of increasing concentrations of OMP on the marine microalga Tetraselmis suecica analysing several cytotoxicity biomarkers by flow cytometry after 24h of exposure. Results showed that OMP caused a decrease in growth and autofluorescence, an increase in cellular volume and intracellular complexity, hyperpolarization of cytoplasmic and mitochondrial membranes and intracellular acidification...
August 2, 2017: Aquatic Toxicology
https://www.readbyqxmd.com/read/28800249/reply-from-authors-of-correlation-of-lci-with-hyperpolarized-129-xe-magnetic-resonance-imaging-in-pediatric-cf-subjects
#6
Nikhil Kanhere, Marcus J Couch, Jonathan H Rayment, Felix Ratjen, Giles Santyr
No abstract text is available yet for this article.
August 11, 2017: American Journal of Respiratory and Critical Care Medicine
https://www.readbyqxmd.com/read/28799763/iminothioethers-as-hydrogen-sulfide-donors-from-the-gasotransmitter-release-to-the-vascular-effects
#7
Elisabetta Barresi, Giulia Nesi, Valentina Citi, Eugenia Piragine, Ilaria Piano, Sabrina Taliani, Federico Da Settimo, Simona Rapposelli, Lara Testai, Maria Cristina Breschi, Claudia Gargini, Vincenzo Calderone, Alma Martelli
The gasotransmitter hydrogen sulfide (H2S) is an important tuner of the cardiovascular homeostasis and its deficiency is etiologically associated with a number of cardiovascular diseases. Therefore, the research of original moieties able to release H2S represents a timely issue for drug discovery. In this work, we developed a collection of iminothioethers (ITEs), exhibiting H2S-releasing properties and producing vasorelaxing effects on rat aortic rings. Derivatives 4 and 11, selected as representative of slow and fast rate H2S-donors respectively, produced a complete recovery of the basal coronary flow, reverting the AngII-induced effects in isolated rat hearts...
August 11, 2017: Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/28797687/the-role-of-nitric-oxide-in-spectral-information-processing-in-the-distal-turtle-retina
#8
Elena Segal, Ido Perlman
Chromaticity type horizontal cells (C-type HCs) are the first retinal neurons exhibiting spectral information processing in cold-blooded vertebrates. The simple input of hyperpolarizing responses of cone photoreceptors is transformed in the C-type HCs into spectral opponent output. Nitric oxide (NO), a known background neuromodulator in the distal retina, was tested here for its effects upon spectral information processing by C-type HCs in the retina of turtle. Photoresponses were intracellularly recorded from C-type HCs, using light stimuli of different wavelength, applied over backgrounds of different wavelengths, and changing retinal NO level...
August 7, 2017: Vision Research
https://www.readbyqxmd.com/read/28791701/electrophysiological-properties-of-basal-forebrain-cholinergic-neurons-identified-by-genetic-and-optogenetic-tagging
#9
Gretchen Y López-Hernández, Mala Ananth, Li Jiang, Elizabeth C Ballinger, David A Talmage, Lorna W Role
Recent developments in the generation of neuronal population-specific, genetically modified mouse lines have allowed precise identification and selective stimulation of cholinergic neurons in vivo. Although considerably less laborious than studies conducted with post hoc identification of cholinergic neurons by immunostaining, it is not known whether the genetically based labeling procedures that permit in vivo identification are electrophysiologically benign. In this study, we use mice carrying a bacterial artificial chromosome transgene that drives expression of a tau-green fluorescent fusion protein specifically in cholinergic neurons...
August 2017: Journal of Neurochemistry
https://www.readbyqxmd.com/read/28782641/nitric-oxide-cgmp-signaling-via-guanylyl-cyclase-isoform-1-modulates-glutamate-and-gaba-release-in-somatosensory-cortex-of-mice
#10
Qi Wang, Evanthia Mergia, Doris Koesling, Thomas Mittmann
In hippocampus, two guanylyl cyclases (NO-GC1 and NO-GC2) are involved in the transduction of the effects of nitric oxide (NO) on synaptic transmission. However, the respective roles of the NO-GC isoforms on synaptic transmission are less clear in other regions of the brain. In the present study, we used knock-out mice deficient for the NO-GC1 isoform (NO-GC1 KO) to analyze its role in the glutamatergic and GABAergic neurotransmission at pyramidal neurons in layers II/III of somatosensory cortex. NO-GC1 KO slices revealed reduced frequencies of miniature excitatory- and inhibitory-postsynaptic currents, increased paired-pulse ratios and decreased input-output curves of evoked signals, which indicated the reduction of glutamate and GABA release in NO-GC1 KO mice...
August 4, 2017: Neuroscience
https://www.readbyqxmd.com/read/28782029/eye-motion-triggered-self-powered-mechnosensational-communication-system-using-triboelectric-nanogenerator
#11
Xianjie Pu, Hengyu Guo, Jie Chen, Xue Wang, Yi Xi, Chenguo Hu, Zhong Lin Wang
Mechnosensational human-machine interfaces (HMIs) can greatly extend communication channels between human and external devices in a natural way. The mechnosensational HMIs based on biopotential signals have been developing slowly owing to the low signal-to-noise ratio and poor stability. In eye motions, the corneal-retinal potential caused by hyperpolarization and depolarization is very weak. However, the mechanical micromotion of the skin around the corners of eyes has never been considered as a good trigger signal source...
July 2017: Science Advances
https://www.readbyqxmd.com/read/28780694/dose-rate-effects-of-low-let-ionizing-radiation-on-fish-cells
#12
Nguyen T K Vo, Colin B Seymour, Carmel E Mothersill
Radiobiological responses of a highly clonogenic fish cell line, eelB, to low-LET ionizing radiation and effects of dose rates were studied. In acute exposure to 0.1-12 Gy of gamma rays, eelB's cell survival curve displayed a linear-quadratic (LQ) relationship. In the LQ model, α, β, and α/β ratio were 0.0024, 0.037, and 0.065, respectively; for the first time that these values were reported for fish cells. In the multi-target model, n, D o, and D q values were determined to be 4.42, 2.16, and 3.21 Gy, respectively, and were the smallest among fish cell lines being examined to date...
August 5, 2017: Radiation and Environmental Biophysics
https://www.readbyqxmd.com/read/28780133/altered-glua1-gria1-function-and-accumbal-synaptic-plasticity-in-the-clock%C3%AE-19-model-of-bipolar-mania
#13
Puja K Parekh, Darius Becker-Krail, Poornima Sundaravelu, Shinsuke Ishigaki, Haruo Okado, Gen Sobue, Yanhua Huang, Colleen A McClung
BACKGROUND: Disruptions in circadian rhythms are associated with an increased risk for bipolar disorder. Moreover, studies show that the circadian protein CLOCK (circadian locomotor output cycles kaput) is involved in regulating monoaminergic systems and mood-related behavior. However, the molecular and synaptic mechanisms underlying this relationship remain poorly understood. METHODS: Using ex vivo whole-cell patch-clamp electrophysiology in ClockΔ19 mutant and wild-type mice we characterized alterations in excitatory synaptic transmission, strength, and intrinsic excitability of nucleus accumbens (NAc) neurons...
June 27, 2017: Biological Psychiatry
https://www.readbyqxmd.com/read/28778087/pkm2-activation-sensitizes-cancer-cells-to-growth-inhibition-by-2-deoxy-d-glucose
#14
Sui Seng Tee, Jae Mo Park, Ralph E Hurd, Kyle R Brimacombe, Matthew B Boxer, Tarik F Massoud, Brian K Rutt, Daniel M Spielman
Cancer metabolism has emerged as an increasingly attractive target for interfering with tumor growth. Small molecule activators of pyruvate kinase isozyme M2 (PKM2) suppress tumor formation but have an unknown effect on established tumors. We demonstrate that TEPP-46, a PKM2 activator, results in increased glucose consumption, providing the rationale for combining PKM2 activators with the toxic glucose analog, 2-deoxy-D-glucose (2-DG). Combination treatment resulted in reduced viability of a range of cell lines in standard cell culture conditions at concentrations of drugs that had no effect when used alone...
July 26, 2017: Oncotarget
https://www.readbyqxmd.com/read/28776687/mesenchymal-stem-cell-differentiation-control-by-calcium-activated-potassium-channels
#15
REVIEW
Ekaterina Pchelintseva, Mustafa B A Djamgoz
Mesenchymal stem cells (MSCs) are widely used in modern medicine for which understanding the mechanisms controlling their differentiation is fundamental. Ion channels offer novel insights to this process because of their role in modulating membrane potential and intracellular milieu. Here, we evaluate the contribution of calcium-activated potassium (KCa ) channels to the three main components of MSC differentiation: initiation, proliferation and migration. First, we demonstrate the importance of the membrane potential (Vm ) and the apparent association of hyperpolarization with differentiation...
August 4, 2017: Journal of Cellular Physiology
https://www.readbyqxmd.com/read/28769073/compensatory-vasodilator-mechanisms-in-the-ophthalmic-artery-of-endothelial-nitric-oxide-synthase-gene-knockout-mice
#16
Caroline Manicam, Natalja Ginter, Huige Li, Ning Xia, Evgeny Goloborodko, Jenia Kouchek Zadeh, Aytan Musayeva, Norbert Pfeiffer, Adrian Gericke
Nitric oxide (NO) generated by endothelial nitric oxide synthase (eNOS) plays an important role in the maintenance of ocular vascular homeostasis. Therefore, perturbations in vascular NO synthesis have been implicated in the pathogenesis of several ocular diseases. We recently reported that eNOS contributes significantly to vasodilation of the mouse ophthalmic artery. Interestingly, dilatory responses were also retained in eNOS gene-deficient mice (eNOS-/-), indicating inherent endothelial adaptive mechanism(s) that act as back-up systems in chronic absence of eNOS to preserve vasorelaxation...
August 2, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28768770/nmda-receptors-mediate-leptin-signaling-and-regulate-potassium-channel-trafficking-in-pancreatic-%C3%AE-cells
#17
Yi Wu, Dale A Fortin, Veronica A Cochrane, Pei-Chun Chen, Show-Ling Shyng
NMDA receptors (NMDARs) are Ca2+-permeant, ligand-gated ion channels activated by the excitatory neurotransmitter glutamate and have well-characterized roles in the nervous system. The expression and function of NMDARs in pancreatic β cells, by contrast, are poorly understood. Here, we report a novel function of NMDARs in β-cells. Using a combination of biochemistry, electrophysiology, and imaging techniques we now show that NMDARs have a key role in mediating the effect of leptin to modulate β-cell electrical activity by promoting AMP-activated protein kinase (AMPK)-dependent trafficking of KATP and Kv2...
August 2, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28768741/theta-frequency-selectivity-in-the-somatic-spike-triggered-average-of-rat-hippocampal-pyramidal-neurons-is-dependent-on-hcn-channels
#18
Anindita Das, Rishikesh Narayanan
The ability to distill specific frequencies from complex spatiotemporal patterns of afferent inputs is a pivotal functional requirement for neurons residing in networks receiving frequency-multiplexed inputs. Although the expression of theta-frequency subthreshold resonance is established in hippocampal pyramidal neurons, it is not known if their spike initiation dynamics manifest spectral selectivity or if their intrinsic properties are tuned to process gamma-frequency inputs. Here, we measured the spike-triggered average (STA) of rat hippocampal pyramidal neurons through electrophysiological recordings and quantified spectral selectivity in their spike initiation dynamics and their coincidence detection window (CDW)...
August 2, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28762726/intracellular-uncaging-of-cgmp-with-blue-light
#19
Hitesh K Agarwal, Shenyu Zhai, D James Surmeier, Graham C R Ellis-Davies
We have made a new caged cGMP that is photolyzed with blue light. Using our recently developed derivative of 7-diethylaminocourmarin (DEAC) called DEAC450, we synthesized coumarin phosphoester derivatives of cGMP with two negative charges appended to the DEAC450 moiety. DEAC450-cGMP is freely soluble in physiological buffer without the need for any organic cosolvents. With a photolysis quantum yield of 0.18 and an extinction coefficient of 43 000 M(-1) cm(-1) at 453 nm, DEAC450-cGMP is the most photosensitive caged cGMP made to date...
August 1, 2017: ACS Chemical Neuroscience
https://www.readbyqxmd.com/read/28761080/serotonin-inputs-to-the-dorsal-bnst-modulate-anxiety-in-a-5-ht1a-receptor-dependent-manner
#20
A L Garcia-Garcia, S Canetta, J M Stujenske, N S Burghardt, M S Ansorge, A Dranovsky, E D Leonardo
Serotonin (5-HT) neurons project from the raphe nuclei throughout the brain where they act to maintain homeostasis. Here, we study 5-HT inputs into the bed nucleus of the stria terminalis (BNST), a major subdivision of the extended amygdala that has been proposed to regulate responses to anxiogenic environments in humans and rodents. While the dorsal part of the BNST (dBNST) receives dense 5-HT innervation, whether and how 5-HT in the dBNST normally modulates anxiety remains unclear. Using optogenetics, we demonstrate that activation of 5-HT terminals in the dBNST reduces anxiety in a highly anxiogenic environment...
August 1, 2017: Molecular Psychiatry
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