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Hyperpolarization

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https://www.readbyqxmd.com/read/28328174/a-strategy-to-design-hyperpolarized-%C3%A2-%C3%A2-c-magnetic-resonance-probes-using-1-%C3%A2-%C3%A2-c-%C3%AE-amino-acid-as-a-scaffold-structure
#1
Tatsuya Nishihara, Yutaka Kameyama, Hiroshi Nonaka, Yoichi Takakusagi, Fuminori Hyodo, Kazuhiro Ichikawa, Shinsuke Sando
Hyperpolarization is an emerging method that dramatically enhances NMR signal intensity. As a result of the increased sensitivity, hyperpolarized (HP) NMR molecular probes can be used to perform time-resolved spectroscopy and imaging in vitro and in vivo. It is however challenging to design such probes de novo. We herein report the [1-¹³C]α-amino acid as a scaffold structure to design HP ¹³C NMR molecular probe. The [1-¹³C]α-amino acid can be converted to various HP ¹³C chemical probes that show sufficient chemical shift change by altering the chemical state of α-nitrogen upon the interaction with the target...
March 22, 2017: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/28327344/direct-activation-of-ca-2-and-voltage-gated-potassium-channels-of-large-conductance-by-anandamide-in-endothelial-cells-does-not-support-the-presence-of-endothelial-atypical-cannabinoid-receptor
#2
Alexander I Bondarenko, Olga Panasiuk, Iryna Okhai, Fabrizio Montecucco, Karim J Brandt, Francois Mach
Endocannabinoid anandamide induces endothelium-dependent relaxation commonly attributed to stimulation of the G-protein coupled endothelial anandamide receptor. The study addressed the receptor-independent effect of anandamide on large conductance Ca(2+)-dependent K(+) channels expressed in endothelial cell line EA.hy926. Under resting conditions, 10µM anandamide did not significantly influence the resting membrane potential. In a Ca(2+)-free solution the cells were depolarized by ~10 mV. Further administration of 10µM anandamide hyperpolarized the cells by ~8 mV...
March 19, 2017: European Journal of Pharmacology
https://www.readbyqxmd.com/read/28325790/dopamine-terminals-from-the-ventral-tegmental-area-gate-intrinsic-inhibition-in-the-prefrontal-cortex
#3
William C Buchta, Stephen V Mahler, Benjamin Harlan, Gary S Aston-Jones, Arthur C Riegel
Spike frequency adaptation (SFA or accommodation) and calcium-activated potassium channels that underlie after-hyperpolarization potentials (AHP) regulate repetitive firing of neurons. Precisely how neuromodulators such as dopamine from the ventral tegmental area (VTA) regulate SFA and AHP (together referred to as intrinsic inhibition) in the prefrontal cortex (PFC) remains unclear. Using whole cell electrophysiology, we measured intrinsic inhibition in prelimbic (PL) layer 5 pyramidal cells of male adult rats...
March 2017: Physiological Reports
https://www.readbyqxmd.com/read/28322385/dicarboxylic-acids-as-ph-sensors-for-hyperpolarized-13-c-magnetic-resonance-spectroscopic-imaging
#4
D E Korenchan, C Taglang, C von Morze, J E Blecha, J W Gordon, R Sriram, P E Z Larson, D B Vigneron, H F VanBrocklin, J Kurhanewicz, D M Wilson, R R Flavell
Imaging tumoral pH may help to characterize aggressiveness, metastasis, and therapeutic response. We report the development of hyperpolarized [2-(13)C,D10]diethylmalonic acid, which exhibits a large pH-dependent (13)C chemical shift over the physiological range. We demonstrate that co-polarization with [1-(13)C,D9]tert-butanol accurately measures pH via(13)C NMR and magnetic resonance spectroscopic imaging in phantoms.
March 21, 2017: Analyst
https://www.readbyqxmd.com/read/28320840/k-channel-kv3-4-is-essential-for-axon-growth-by-limiting-the-influx-of-ca-2-into-growth-cones
#5
Chia-Yi Huang, Cheng-Chang Lien, Chau-Fu Cheng, Ting-Yun Yen, Chieh-Ju Chen, Meei-Ling Tsaur
Membrane excitability in the axonal growth cones of embryonic neurons influences axon growth. Voltage-gated K(+) (Kv) channels are key factors in controlling membrane excitability, but whether they regulate axon growth remains unclear. Here, we report that Kv3.4 is expressed in the axonal growth cones of embryonic spinal commissural neurons, motoneurons, dorsal root ganglion neurons, retinal ganglion cells and callosal projection neurons during axon growth. Our in vitro (cultured dorsal spinal neurons of chick embryos) and in vivo (developing chick spinal commissural axons and rat callosal axons) findings demonstrate that knockdown of Kv3...
March 20, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28319892/mitochondrial-hyperpolarization-in-ipsc-derived-neurons-from-patients-of-ftdp-17-with-10-16-mapt-mutation-leads-to-oxidative-stress-and-neurodegeneration
#6
Noemí Esteras, Jonathan D Rohrer, John Hardy, Selina Wray, Andrey Y Abramov
Tau protein inclusions are a frequent hallmark of a variety of neurodegenerative disorders. The 10+16 intronic mutation in MAPT gene, encoding tau, causes frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17), by altering the splicing of the gene and inducing an increase in the production of 4R tau isoforms, which are more prone to aggregation. However, the molecular mechanisms linking increased 4R tau to neurodegeneration are not well understood. Here, we have used iPSC-derived neurons from patients of FTDP-17 carrying the 10+16 mutation to study the molecular mechanisms underlying neurodegeneration...
March 10, 2017: Redox Biology
https://www.readbyqxmd.com/read/28319610/capillary-k-sensing-initiates-retrograde-hyperpolarization-to-increase-local-cerebral-blood-flow
#7
Thomas A Longden, Fabrice Dabertrand, Masayo Koide, Albert L Gonzales, Nathan R Tykocki, Joseph E Brayden, David Hill-Eubanks, Mark T Nelson
Blood flow into the brain is dynamically regulated to satisfy the changing metabolic requirements of neurons, but how this is accomplished has remained unclear. Here we demonstrate a central role for capillary endothelial cells in sensing neural activity and communicating it to upstream arterioles in the form of an electrical vasodilatory signal. We further demonstrate that this signal is initiated by extracellular K(+) -a byproduct of neural activity-which activates capillary endothelial cell inward-rectifier K(+) (KIR2...
March 20, 2017: Nature Neuroscience
https://www.readbyqxmd.com/read/28318721/-physiology-of-the-visual-retinal-signal-from-phototransduction-to-the-visual-cycle
#8
REVIEW
C Salesse
The retinal photoreceptors (rods and cones) are responsible for light absorption and transduction of the signal, which is transmitted to the other retinal nerve cells and then to the brain. The chromophore of visual pigments of rods and cones is a particular isomer of a vitamin A derivative. Light absorption by this chromophore leads to its isomerization and to a phototransduction cascade, which results in photoreceptor hyperpolarization and cessation of glutamate secretion at their synaptic terminals. Phototransduction of cones and rods differs in their signal amplification and inactivation, which is consistent with their respective functions...
March 17, 2017: Journal Français D'ophtalmologie
https://www.readbyqxmd.com/read/28315276/the-sigma-1-receptor-a-therapeutic-target-for-the-treatment-of-als
#9
Timur A Mavlyutov, Erin M Baker, Tasher M Losenegger, Jaimie R Kim, Brian Torres, Miles L Epstein, Arnold E Ruoho
The membrane bound 223 amino acid Sigma-1 Receptor (S1R) serves as a molecular chaperone and functional regulator of many signaling proteins. Spinal cord motor neuron activation occurs, in part, via large ventral horn cholinergic synapses called C-boutons/C-terminals. Chronic excitation of motor neurons and alterations in C-terminals has been associated with Amyotrophic Lateral Sclerosis (ALS ). The S1R has an important role in regulating motor neuron function. High levels of the S1R are localized in postsynaptic endoplasmic reticulum (ER) subsurface cisternae within 10-20 nm of the plasma membrane that contain muscarinic type 2 acetylcholine receptors (M2AChR), calcium activated potassium channels (Kv2...
2017: Advances in Experimental Medicine and Biology
https://www.readbyqxmd.com/read/28314207/a-pulse-sequence-for-singlet-to-heteronuclear-magnetization-transfer-s2hm
#10
Gabriele Stevanato, James Eills, Christian Bengs, Giuseppe Pileio
We have recently demonstrated, in the context of para-hydrogen induced polarization (PHIP), the conversion of hyperpolarized proton singlet order into heteronuclear magnetisation can be efficiently achieved via a new sequence named S2hM (Singlet to heteronuclear Magnetisation). In this paper we give a detailed theoretical description, supported by an experimental illustration, of S2hM. Theory and experiments on thermally polarized samples demonstrate the proposed method is robust to frequency offset mismatches and radiofrequency field inhomogeneities...
March 6, 2017: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/28302447/dcebio-facilitates-myogenic-differentiation-via-intermediate-conductance-ca-2-activated-k-channel-activation-in-c2c12-myoblasts
#11
Shoko Tanaka, Yuko Ono, Kazuho Sakamoto
Membrane hyperpolarization is suggested to be a trigger for skeletal muscle differentiation. We investigated whether DCEBIO, an opener of the small/intermediate conductance Ca(2+) activated K(+) (SKCa/IKCa) channels, increase myogenic differentiation in C2C12 skeletal myoblasts. DCEBIO significantly increased myotube formation, protein expression level of myosin heavy chain II, and mRNA expression level of myogenin in C2C12 myoblasts cultured in differentiation medium. DCEBIO induced myotube formation and hyperpolarization were reduced by the IKCa channel blocker TRAM-34, but not by the SKCa channel blocker apamin...
February 17, 2017: Journal of Pharmacological Sciences
https://www.readbyqxmd.com/read/28300845/digoxin-induced-retinal-degeneration-depends-on-rhodopsin
#12
Britta Landfried, Marijana Samardzija, Maya Barben, Christian Schori, Katrin Klee, Federica Storti, Christian Grimm
Na,K-ATPases are energy consuming ion pumps that are required for maintaining ion homeostasis in most cells. In the retina, Na,K-ATPases are especially important to sustain the dark current in photoreceptor cells needed for rapid hyperpolarization of rods and cones in light. Cardiac glycosides like digoxin inhibit the activity of Na,K-ATPases by targeting their catalytic alpha subunits. This leads to a disturbed ion balance, which can affect cellular function and survival. Here we show that the treatment of wild-type mice with digoxin leads to severe retinal degeneration and loss of vision...
March 16, 2017: Cell Death & Disease
https://www.readbyqxmd.com/read/28298655/dual-nep-ece-inhibition-improves-endothelial-function-in-mesenteric-resistance-arteries-of-32-week-old-shr
#13
Pieter Lemkens, Leon Ja Spijkers, Merlijn J Meens, Jelly Nelissen, Ben Janssen, Stephan Lm Peters, Paul Mh Schiffers, Jo Gr De Mey
Endothelin 1 (ET-1), a potent vasoconstrictor, pro-mitogenic and pro-inflammatory peptide, may promote development of endothelial dysfunction and arterial remodeling. ET-1 can be formed through cleavage of big-ET-1 by endothelin-converting enzyme (ECE) or neutral endopeptidase (NEP). We investigated whether chronic treatment with the novel dual NEP/ECE inhibitor SOL1 improves functional and structural properties of resistance-sized arteries of 32-week-old male spontaneously hypertensive rats (SHR). SHR received a chronic 4-week treatment with SOL1, losartan or hydralazine...
March 16, 2017: Hypertension Research: Official Journal of the Japanese Society of Hypertension
https://www.readbyqxmd.com/read/28298006/nuclear-magnetic-resonance-diffusion-pore-imaging-experimental-phase-detection-by-double-diffusion-encoding
#14
Kerstin Demberg, Frederik Bernd Laun, Johannes Windschuh, Reiner Umathum, Peter Bachert, Tristan Anselm Kuder
Diffusion pore imaging is an extension of diffusion-weighted nuclear magnetic resonance imaging enabling the direct measurement of the shape of arbitrarily formed, closed pores by probing diffusion restrictions using the motion of spin-bearing particles. Examples of such pores comprise cells in biological tissue or oil containing cavities in porous rocks. All pores contained in the measurement volume contribute to one reconstructed image, which reduces the problem of vanishing signal at increasing resolution present in conventional magnetic resonance imaging...
February 2017: Physical Review. E
https://www.readbyqxmd.com/read/28296544/the-conduction-system-and-expressions-of-hyperpolarization-activated-cyclic-nucleotide-gated-cation-channel-4-and-connexin43-expressions-in-the-hearts-of-fetal-day-13-mice
#15
Y Wen, B Li
We investigated the development of the sinus node of the heart conduction system by localizing hyperpolarization-activated cyclic nucleotide-gated cation channel 4 (HCN4) and connexin43 (Cx43) in the hearts of fetal day 13 mice. Horizontal serial sections of day 13 whole fetuses were stained by hematoxylin and eosin and immunofluorescence to identify myocardial cells that express HCN4, hyperpolarization-activated cyclic nucleotide-gated cation channel 2 (HCN2) and Cx43. Expression levels of HCN4 and Cx43 were determined by quantitative RT-PCR in both fetal day 13 and adult mice...
2017: Biotechnic & Histochemistry: Official Publication of the Biological Stain Commission
https://www.readbyqxmd.com/read/28295315/a-comparative-analysis-of-the-physiological-properties-of-neurons-in-the-anterolateral-bed-nucleus-of-the-stria-terminalis-in-the-mus-musculus-rattus-norvegicus-and-macaca-mulatta
#16
Sarah E Daniel, Jidong Guo, Donald G Rainnie
The anterolateral group of the bed nucleus of the stria terminalis (BNSTALG ) is a critical modulator of a variety of rodent and primate behaviors spanning anxiety behavior and drug addiction. Three distinct neuronal cell types have been previously defined in the rat BNSTALG based on differences in the voltage-response to hyperpolarizing and depolarizing current injection. Differences in genetic expression profile between these three cell types suggest electrophysiological cell type may be an indicator for functional differences in the circuit of the rat BNSTALG ...
March 13, 2017: Journal of Comparative Neurology
https://www.readbyqxmd.com/read/28293176/muscarinic-receptors-are-responsible-for-the-cholinergic-modulation-of-projection-neurons-in-the-song-production-brain-nucleus-ra-of-zebra-finches
#17
Wei Meng, Songhua Wang, Lihua Yao, Nan Zhang, Dongfeng Li
Songbirds are a useful model for the study of learned vocal behavior in vertebrates. The robust nucleus of the arcopallium (RA) is a premotor nucleus in the vocal motor pathway. It receives excitatory synaptic inputs from the anterior forebrain pathway. RA also receives cholinergic inputs from the ventral paleostriatum of the basal forebrain. Our previous study showed that carbachol, a non-selective cholinergic receptor agonist, modulates the electrophysiology of RA projection neurons (PNs), indicating that cholinergic modulation of RA may play an important role in song production...
2017: Frontiers in Cellular Neuroscience
https://www.readbyqxmd.com/read/28290535/continuous-flow-dnp-polarizer-for-mri-applications-at-1-5%C3%A2-t
#18
V Denysenkov, M Terekhov, R Maeder, S Fischer, S Zangos, T Vogl, T F Prisner
Here we describe a new hyperpolarization approach for magnetic resonance imaging applications at 1.5 T. Proton signal enhancements of more than 20 were achieved with a newly designed multimode microwave resonator situated inside the bore of the imager and used for Overhauser dynamic nuclear polarization of the water proton signal. Different from other approaches in our setup the hyperpolarization is achieved continuously by liquid water flowing through the polarizer under continuous microwave excitation. With an available flow rate of up to 1...
March 14, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28288417/solvent-suppression-in-dnp-enhanced-solid-state-nmr
#19
Jayasubba Reddy Yarava, Sachin Rama Chaudhari, Aaron J Rossini, Anne Lesage, Lyndon Emsley
We show how DNP enhanced solid-state NMR spectra can be dramatically simplified by suppression of solvent signals. This is achieved by (i) exploiting the paramagnetic relaxation enhancement of solvent signals relative to materials substrates, or (ii) by using short cross-polarization contact times to transfer hyperpolarization to only directly bonded carbon-13 nuclei in frozen solutions. The methods are evaluated for organic microcrystals, surfaces and frozen solutions. We show how this allows for the acquisition of high-resolution DNP enhanced proton-proton correlation experiments to measure inter-nuclear proximities in an organic solid...
March 1, 2017: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/28287157/neurovascular-microcirculatory-vasodilation-mediated-by-c-fibers-and-transient-receptor-potential-vanilloid-type-1-channels-trpv-1-is-impaired-in-type-1-diabetes
#20
P Marche, S Dubois, P Abraham, E Parot-Schinkel, L Gascoin, A Humeau-Heurtier, P H Ducluzeau, G Mahe
Microvascular dysfunction may have an early onset in type 1 diabetes (T1D) and can precede major complications. Our objectives were to assess the endothelial-dependent (acetylcholine, ACh; and post-occlusive hyperemia, PORH), non-endothelial-dependent (sodium nitroprusside, SNP) and neurovascular-dependent (local heating, LH and current induced vasodilation, CIV) microcirculatory vasodilation in T1D patients compared with matched control subjects using a laser speckle contrast imager. Seventeen T1D patients - matched with 17 subjects according to age, gender, Body-Mass-Index, and smoking status - underwent macro- and microvascular investigations...
March 13, 2017: Scientific Reports
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