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Channelrhodopsin

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https://www.readbyqxmd.com/read/28708765/distinct-behavioral-responses-evoked-by-selective-optogenetic-stimulation-of-the-major-trpv1-and-mrgd-subsets-of-c-fibers
#1
Hélène Beaudry, Ihab Daou, Ariel R Ase, Alfredo Ribeiro-da-Silva, Philippe Séguéla
Primary C-fiber nociceptors are broadly divided into peptidergic and non-peptidergic afferents. TRPV1 is a thermosensitive cation channel mainly localized in peptidergic nociceptors whereas MrgD is a sensory G protein-coupled receptor expressed in most non-peptidergic nociceptive afferents. TRPV1 and MrgD fibers have been reported to be primarily involved in thermal and mechanical nociception, respectively. Yet, their functional assessment in somatosensory transmission relied on ablation strategies that do not account for compensatory mechanisms...
July 12, 2017: Pain
https://www.readbyqxmd.com/read/28685774/immobility-responses-are-induced-by-photoactivation-of-single-glomerular-species-responsive-to-fox-odour-tmt
#2
Harumi Saito, Hirofumi Nishizumi, Satoshi Suzuki, Hideyuki Matsumoto, Nao Ieki, Takaya Abe, Hiroshi Kiyonari, Masahiko Morita, Hideo Yokota, Nozomi Hirayama, Takahiro Yamazaki, Takefumi Kikusui, Kensaku Mori, Hitoshi Sakano
Fox odour 2,4,5-trimethyl thiazoline (TMT) is known to activate multiple glomeruli in the mouse olfactory bulb (OB) and elicits strong fear responses. In this study, we screened TMT-reactive odourant receptors and identified Olfr1019 with high ligand reactivity and selectivity, whose glomeruli are located in the posterodorsal OB. In the channelrhodopsin knock-in mice for Olfr1019, TMT-responsive olfactory-cortical regions were activated by photostimulation, leading to the induction of immobility, but not aversive behaviour...
July 7, 2017: Nature Communications
https://www.readbyqxmd.com/read/28671548/motoneurons-regulate-the-central-pattern-generator-during-drug-induced-locomotor-like-activity-in-the-neonatal-mouse
#3
Melanie Falgairolle, Joshua G Puhl, Avinash Pujala, Wenfang Liu, Michael James O'Donovan
Motoneurons are traditionally viewed as the output of the spinal cord that do not influence locomotor rhythmogenesis. We assessed the role of motoneuron firing during ongoing locomotor-like activity in neonatal mice expressing archaerhopsin-3 (Arch), halorhodopsin (eNpHR), or channelrhodopsin-2 (ChR2) in Choline acetyltransferase expressing neurons (ChAT(+)) or the LIM-homeodomain transcription factor Isl1(+) neurons. Illumination of the lumbar cord in mice expressing eNpHR or Arch in ChAT(+) or Isl1(+) neurons, depressed motoneuron discharge, transiently decreased the frequency, and perturbed the phasing of the locomotor-like rhythm...
July 3, 2017: ELife
https://www.readbyqxmd.com/read/28668267/measurement-of-phase-resetting-curves-using-optogenetic-barrage-stimuli
#4
Matthew H Higgs, Charles J Wilson
BACKGROUND: The phase resetting curve (PRC) is a primary measure of a rhythmically firing neuron's responses to synaptic input, quantifying the change in phase of the firing oscillation as a function of the input phase. PRCs provide information about whether neurons will synchronize due to synaptic coupling or shared input. However, PRC estimation has been limited to in vitro preparations where stable intracellular recordings can be obtained and background activity is minimal, and new methods are required for in vivo applications...
June 28, 2017: Journal of Neuroscience Methods
https://www.readbyqxmd.com/read/28667669/optogenetic-stimulation-of-dentate-gyrus-engrams-restores-memory-in-alzheimer-s-disease-mice
#5
Jennifer N Perusini, Stephanie A Cajigas, Omid Cohensedgh, Sean C Lim, Ina P Pavlova, Zoe R Donaldson, Christine A Denny
Alzheimer's disease (AD) is a prevalent neurodegenerative disorder characterized by amyloid-beta (Aβ) plaques and tau neurofibrillary tangles. APPswe/PS1dE9 (APP/PS1) mice have been developed as an AD model and are characterized by plaque formation at 4-6 months of age. Here, we sought to better understand AD-related cognitive decline by characterizing various types of memory. In order to better understand how memory declines with AD, APP/PS1 mice were bred with ArcCreER(T2) mice. In this line, neural ensembles activated during memory encoding can be indelibly tagged and directly compared with neural ensembles activated during memory retrieval (i...
July 1, 2017: Hippocampus
https://www.readbyqxmd.com/read/28667175/the-relevance-of-agrp-neuron-derived-gaba-inputs-to-pomc-neurons-differs-for-spontaneous-and-evoked-release
#6
Andrew R Rau, Shane T Hentges
Hypothalamic agouti-related peptide (AgRP) neurons potently stimulate food intake, whereas proopiomelanocortin (POMC) neurons inhibit feeding. Whether AgRP neurons exert their orexigenic actions, at least in part, by inhibiting anorexigenic POMC neurons remains unclear. Here, the connectivity between GABA-releasing AgRP neurons and POMC neurons was examined in brain slices from male and female mice. Spontaneous GABA-mediated inhibitory postsynaptic currents (sIPSCs) in POMC neurons were unaffected by disturbing GABA release from AgRP neurons either by cell-type-specific deletion of the vesicular GABA transporter or by expression of botulinum toxin in AgRP neurons to prevent VAMP2-dependent vesicle fusion...
June 30, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28660935/targeted-and-efficient-activation-of-channelrhodopsins-expressed-in-living-cells-via-specifically-bound-upconversion-nanoparticles
#7
Kanchan Yadav, Ai-Chuan Chou, Rajesh Kumar Ulaganathan, Hua-De Gao, Hsien-Ming Lee, Chien-Yuan Pan, Yit-Tsong Chen
Optogenetics is an innovative technology now widely adopted by researchers in different fields of biological sciences. However, most light-sensitive proteins adopted in optogenetics are excited by ultraviolet or visible light which has a weak tissue penetration capability. Upconversion nanoparticles (UCNPs), which absorb near-infrared (NIR) light to emit shorter wavelength light, can help address this issue. In this report, we demonstrated the target selectivity by specifically conjugating the UCNPs with channelrhodopsin-2 (ChR2)...
July 13, 2017: Nanoscale
https://www.readbyqxmd.com/read/28660248/optogenetic-evidence-for-a-direct-circuit-linking-nociceptive-transmission-through-the-parabrachial-complex-with-pain-modulating-neurons-of-the-rostral-ventromedial-medulla-rvm
#8
QiLiang Chen, Zachary Roeder, Ming-Hua Li, YangMiao Zhang, Susan L Ingram, Mary M Heinricher
The parabrachial complex (PB) is a functionally and anatomically complex structure involved in a range of homeostatic and sensory functions, including nociceptive transmission. There is also evidence that PB can engage descending pain-modulating systems, the best characterized of which is the rostral ventromedial medulla (RVM). Two distinct classes of RVM neurons, "ON-cells" and "OFF-cells," exert net pronociceptive and anti-nociceptive effects, respectively. PB was recently shown to be a relay of nociceptive information to RVM ON- and OFF-cells...
May 2017: ENeuro
https://www.readbyqxmd.com/read/28659709/meclofenamic-acid-improves-the-signal-to-noise-ratio-for-visual-responses-produced-by-ectopic-expression-of-human-rod-opsin
#9
Cyril G Eleftheriou, Jasmina Cehajic-Kapetanovic, Franck P Martial, Nina Milosavljevic, Robert A Bedford, Robert J Lucas
PURPOSE: Retinal dystrophy through outer photoreceptor cell death affects 1 in 2,500 people worldwide with severe impairment of vision in advanced stages of the disease. Optogenetic strategies to restore visual function to animal models of retinal degeneration by introducing photopigments to neurons spared degeneration in the inner retina have been explored, with variable degrees of success. It has recently been shown that the non-steroidal anti-inflammatory and non-selective gap-junction blocker meclofenamic acid (MFA) can enhance the visual responses produced by an optogenetic actuator (channelrhodopsin) expressed in retinal ganglion cells (RGCs) in the degenerate retina...
2017: Molecular Vision
https://www.readbyqxmd.com/read/28659342/proton-transfer-reactions-in-the-red-light-activatable-channelrhodopsin-variant-reachr-and-their-relevance-for-its-function
#10
Joel C D Kaufmann, Benjamin S Krause, Christiane Grimm, Eglof Ritter, Peter Hegemann, Franz J Bartl
Channelrhodopsins (ChRs) are light-gated ion channels widely used for activating selected cells in large cellular networks. ChR variants with a red-shifted absorption maximum, such as the modified VcChR1 "ReaChR" (λmax = 527 nm), are of particular interest, since longer wavelengths allow optical excitation of cells in deeper layers of organic tissue. In all ChRs investigated so far, proton transfer reactions and hydrogen-bond changes are crucial for the formation of the ion-conducting pore and the selectivity for protons versus cations such as Na(+), K(+), and Ca(2+) (1)...
June 28, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28648497/selective-optogenetic-control-of-purkinje-cells-in-monkey-cerebellum
#11
Yasmine El-Shamayleh, Yoshiko Kojima, Robijanto Soetedjo, Gregory D Horwitz
Purkinje cells of the primate cerebellum play critical but poorly understood roles in the execution of coordinated, accurate movements. Elucidating these roles has been hampered by a lack of techniques for manipulating spiking activity in these cells selectively-a problem common to most cell types in non-transgenic animals. To overcome this obstacle, we constructed AAV vectors carrying the channelrhodopsin-2 (ChR2) gene under the control of a 1 kb L7/Pcp2 promoter. We injected these vectors into the cerebellar cortex of rhesus macaques and tested vector efficacy in three ways...
July 5, 2017: Neuron
https://www.readbyqxmd.com/read/28630812/molecular-properties-of-a-dtd-channelrhodopsin-from-guillardia-theta
#12
Yumeka Yamauchi, Masae Konno, Shota Ito, Satoshi P Tsunoda, Keiichi Inoue, Hideki Kandori
Microbial rhodopsins are membrane proteins found widely in archaea, eubacteria and eukaryotes (fungal and algal species). They have various functions, such as light-driven ion pumps, light-gated ion channels, light sensors and light-activated enzymes. A light-driven proton pump bacteriorhodopsin (BR) contains a DTD motif at positions 85, 89, and 96, which is unique to archaeal proton pumps. Recently, channelrhodopsins (ChRs) containing the DTD motif, whose sequential identity is ~20% similar to BR and to cation ChRs in Chlamydomonas reinhardtii (CrCCRs), were found...
2017: Biophysics and Physicobiology
https://www.readbyqxmd.com/read/28628197/vesicular-acetylcholine-transporter-vacht-overexpression-induces-major-modifications-of-striatal-cholinergic-interneuron-morphology-and-function
#13
Helena Janickova, Vania F Prado, Marco A M Prado, Salah El Mestikawy, Véronique Bernard
Striatal cholinergic interneurons (CIN) are pivotal for the regulation of the striatal network. Acetylcholine (ACh) released by CIN is centrally involved in reward behavior as well as locomotor or cognitive functions. Recently, BAC transgenic mice expressing channelrhodopsin-2 (ChR2) protein under the control of the choline acetyltransferase (ChAT) promoter (ChAT-ChR2) and displaying almost 50 extra copies of the VAChT gene were used to dissect cholinergic circuit connectivity and function using optogenetic approaches...
June 19, 2017: Journal of Neurochemistry
https://www.readbyqxmd.com/read/28611221/optogenetic-control-of-mitochondrial-metabolism-and-ca-2-signaling-by-mitochondria-targeted-opsins
#14
Tatiana Tkatch, Elisa Greotti, Gytis Baranauskas, Diana Pendin, Soumitra Roy, Luliaoana I Nita, Jennifer Wettmarshausen, Matthias Prigge, Ofer Yizhar, Orian S Shirihai, Daniel Fishman, Michal Hershfinkel, Ilya A Fleidervish, Fabiana Perocchi, Tullio Pozzan, Israel Sekler
Key mitochondrial functions such as ATP production, Ca(2+) uptake and release, and substrate accumulation depend on the proton electrochemical gradient (ΔμH(+)) across the inner membrane. Although several drugs can modulate ΔμH(+), their effects are hardly reversible, and lack cellular specificity and spatial resolution. Although channelrhodopsins are widely used to modulate the plasma membrane potential of excitable cells, mitochondria have thus far eluded optogenetic control. Here we describe a toolkit of optometabolic constructs based on selective targeting of channelrhodopsins with distinct functional properties to the inner mitochondrial membrane of intact cells...
June 27, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28592174/at-light-speed-advances-in-optogenetic-systems-for-regulating-cell-signaling-and-behavior
#15
Nicole A Repina, Alyssa Rosenbloom, Abhirup Mukherjee, David V Schaffer, Ravi S Kane
Cells are bombarded by extrinsic signals that dynamically change in time and space. Such dynamic variations can exert profound effects on behaviors, including cellular signaling, organismal development, stem cell differentiation, normal tissue function, and disease processes such as cancer. Although classical genetic tools are well suited to introduce binary perturbations, new approaches have been necessary to investigate how dynamic signal variation may regulate cell behavior. This fundamental question is increasingly being addressed with optogenetics, a field focused on engineering and harnessing light-sensitive proteins to interface with cellular signaling pathways...
June 7, 2017: Annual Review of Chemical and Biomolecular Engineering
https://www.readbyqxmd.com/read/28570519/whole-cell-patch-clamp-recordings-for-electrophysiological-determination-of-ion-selectivity-in-channelrhodopsins
#16
Christiane Grimm, Johannes Vierock, Peter Hegemann, Jonas Wietek
Over the past decade, channelrhodopsins became indispensable in neuroscientific research where they are used as tools to non-invasively manipulate electrical processes in target cells. In this context, ion selectivity of a channelrhodopsin is of particular importance. This article describes the investigation of chloride selectivity for a recently identified anion-conducting channelrhodopsin of Proteomonas sulcata via electrophysiological patch-clamp recordings on HEK293 cells. The experimental procedure for measuring light-gated photocurrents demands a fast switchable - ideally monochromatic - light source coupled into the microscope of an otherwise conventional patch-clamp setup...
May 22, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28562670/increased-threshold-of-short-latency-motor-evoked-potentials-in-transgenic-mice-expressing-channelrhodopsin-2
#17
Wei Wu, Wenhui Xiong, Ping Zhang, Lifang Chen, Jianqiao Fang, Christopher Shields, Xiao-Ming Xu, Xiaoming Jin
Transgenic mice that express channelrhodopsin-2 or its variants provide a powerful tool for optogenetic study of the nervous system. Previous studies have established that introducing such exogenous genes usually does not alter anatomical, electrophysiological, and behavioral properties of neurons in these mice. However, in a line of Thy1-ChR2-YFP transgenic mice (line 9, Jackson lab), we found that short-latency motor evoked potentials (MEPs) induced by transcranial magnetic stimulation had a longer latency and much lower amplitude than that of wild type mice...
2017: PloS One
https://www.readbyqxmd.com/read/28526883/openspritzer-an-open-hardware-pressure-ejection-system-for-reliably-delivering-picolitre-volumes
#18
C J Forman, H Tomes, B Mbobo, R J Burman, M Jacobs, T Baden, J V Raimondo
The ability to reliably and precisely deliver picolitre volumes is an important component of biological research. Here we describe a high-performance, low-cost, open hardware pressure ejection system (Openspritzer), which can be constructed from off the shelf components. The device is capable of delivering minute doses of reagents to a wide range of biological and chemical systems. In this work, we characterise the performance of the device and compare it to a popular commercial system using two-photon fluorescence microscopy...
May 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28521132/linking-neurons-to-network-function-and-behavior-by-two-photon-holographic-optogenetics-and-volumetric-imaging
#19
Marco Dal Maschio, Joseph C Donovan, Thomas O Helmbrecht, Herwig Baier
We introduce a flexible method for high-resolution interrogation of circuit function, which combines simultaneous 3D two-photon stimulation of multiple targeted neurons, volumetric functional imaging, and quantitative behavioral tracking. This integrated approach was applied to dissect how an ensemble of premotor neurons in the larval zebrafish brain drives a basic motor program, the bending of the tail. We developed an iterative photostimulation strategy to identify minimal subsets of channelrhodopsin (ChR2)-expressing neurons that are sufficient to initiate tail movements...
May 17, 2017: Neuron
https://www.readbyqxmd.com/read/28518090/flash-and-freeze-a-novel-technique-to-capture-membrane-dynamics-with-electron-microscopy
#20
Shuo Li, Sumana Raychaudhuri, Shigeki Watanabe
Cells constantly change their membrane architecture and protein distribution, but it is extremely difficult to visualize these events at a temporal and spatial resolution on the order of ms and nm, respectively. We have developed a time-resolved electron microscopy technique, "flash-and-freeze," that induces cellular events with optogenetics and visualizes the resulting membrane dynamics by freezing cells at defined time points after stimulation. To demonstrate this technique, we expressed channelrhodopsin, a light-sensitive cation channel, in mouse hippocampal neurons...
May 1, 2017: Journal of Visualized Experiments: JoVE
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