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Channelrhodopsin

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https://www.readbyqxmd.com/read/28325790/dopamine-terminals-from-the-ventral-tegmental-area-gate-intrinsic-inhibition-in-the-prefrontal-cortex
#1
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/28320275/optogenetic-stimulation-increases-level-of-antiapoptotic-protein-bcl-xl-in-neurons
#2
D A Lanshakov, U S Drozd, N N Dygalo
The antiapoptotic protein Bcl-xL is associated with several neuroplastic processes such as formation of synapses, regulation of spontaneous and evoked synaptic responses, and release of neurotransmitters. Dependence of expression on activity of neurons is characteristic for many proteins participating in regulation of neuroplasticity. Whether such property is exhibited by the Bcl-xL protein was analyzed using in vivo optogenetic stimulation of hippocampal glutamatergic neurons expressing channelrhodopsin ChR2H134 under CAMKIIa promoter in the adeno-associated viral vector, followed by immunohistochemical determination of the level of Bcl-xL protein in these neurons and surrounding cells...
March 2017: Biochemistry. Biokhimii︠a︡
https://www.readbyqxmd.com/read/28302720/adjacent-channelrhodopsin-2-residues-within-transmembranes-2-and-7-regulate-cation-selectivity-and-distribution-of-the-two-open-states
#3
Ryan Richards, Robert E Dempski
Channelrhodopsin-2 (ChR2) is a light-activated channel that can conduct cations of multiple valencies down the electrochemical gradient. Under continuous light exposure, ChR2 transitions from a high conducting open state (O1) to a low conducting open state (O2) with differing ion selectivity. The molecular basis for the O1 to O2 transition and how ChR2 modulates selectivity between states is currently unresolved. To this end, we used steered molecular dynamics, electrophysiology, and kinetic modeling to identify residues that contribute to gating and selectivity in discrete open states...
March 16, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28301742/microbial-rhodopsins-diversity-mechanisms-and-optogenetic-applications
#4
Elena G Govorunova, Oleg A Sineshchekov, Hai Li, John L Spudich
Microbial rhodopsins are a family of photoactive retinylidene proteins widespread throughout the microbial world. They are notable for their diversity of function, using variations of a shared seven-transmembrane helix design and similar photochemical reactions to carry out distinctly different light-driven energy and sensory transduction processes. Their study has contributed to our understanding of how evolution modifies protein scaffolds to create new protein chemistry, and their use as tools to control membrane potential with light is fundamental to optogenetics for research and clinical applications...
March 9, 2017: Annual Review of Biochemistry
https://www.readbyqxmd.com/read/28298301/in-vivo-optogenetic-activation-of-nav1-8-cutaneous-nociceptors-and-their-responses-to-natural-stimuli
#5
Megan L Uhelski, Daniel J Bruce, Philippe Seguela, George L Wilcox, Donald A Simone
Optogenetic methods utilizing expression of the light-sensitive protein channelrhodopsin-2 (ChR2) in neurons have enabled selective activation of specific subtypes or groups of neurons to determine their functions. Using a transgenic mouse model in which neurons natively expressing Nav1.8, a tetrodotoxin-resistant voltage-gated sodium channel, also express the light-gated channel ChR2, we have been able to determine the functional properties of Nav1.8-expressing cutaneous nociceptors of the glabrous skin in vivo...
March 15, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28297653/atomistic-study-of-intramolecular-interactions-in-the-closed-state-channelrhodopsin-chimera-c1c2
#6
Monika R VanGordon, Gaurav Gyawali, Steven W Rick, Susan B Rempe
Channelrhodopsins (ChR1 and ChR2) are light-activated ion channels that enable photomobility of microalgae from the genus Chlamydomonas. Despite common use of ChR2 in optogenetics for selective control and monitoring of individual neurons in living tissue, the protein structures remain unresolved. Instead, a crystal structure of the ChR chimera (C1C2), an engineered combination of helices I-V from ChR1, without its C-terminus, and helices VI-VII from ChR2, is used as a template for ChR2 structure prediction...
March 14, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28288335/how-to-control-cyclic-nucleotide-signaling-by-light
#7
REVIEW
Vera Jansen, Jan F Jikeli, Dagmar Wachten
Optogenetics allows to non-invasively manipulate cellular functions with spatio-temporal precision by combining genetic engineering with the control of protein function by light. Since the discovery of channelrhodopsin has pioneered the field, the optogenetic toolkit has been ever expanding and allows now not only to control neuronal activity by light, but rather a multitude of other cellular functions. One important application that has been established in recent years is the light-dependent control of second messenger signaling...
March 10, 2017: Current Opinion in Biotechnology
https://www.readbyqxmd.com/read/28283661/structure-guided-schema-recombination-generates-diverse-chimeric-channelrhodopsins
#8
Claire N Bedbrook, Austin J Rice, Kevin K Yang, Xiaozhe Ding, Siyuan Chen, Emily M LeProust, Viviana Gradinaru, Frances H Arnold
Integral membrane proteins (MPs) are key engineering targets due to their critical roles in regulating cell function. In engineering MPs, it can be extremely challenging to retain membrane localization capability while changing other desired properties. We have used structure-guided SCHEMA recombination to create a large set of functionally diverse chimeras from three sequence-diverse channelrhodopsins (ChRs). We chose 218 ChR chimeras from two SCHEMA libraries and assayed them for expression and plasma membrane localization in human embryonic kidney cells...
March 10, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28271037/cholinergic-neurons-in-the-dorsomedial-hypothalamus-regulate-food-intake
#9
Jae Hoon Jeong, Dong Kun Lee, Young-Hwan Jo
OBJECTIVE: Central cholinergic neural circuits play a role in the regulation of feeding behavior. The dorsomedial hypothalamus (DMH) is considered the appetite-stimulating center and contains cholinergic neurons. Here, we study the role of DMH cholinergic neurons in the control of food intake. METHODS: To selectively stimulate DMH cholinergic neurons, we expressed stimulatory designer receptors exclusively activated by designer drugs (DREADDs) and channelrhodopsins in DMH cholinergic neurons by injection of adeno-associated virus (AAV) vectors into the DMH of choline acetyltransferase (ChAT)-IRES-Cre mice...
March 2017: Molecular Metabolism
https://www.readbyqxmd.com/read/28269273/efficient-assembly-of-multi-color-fiberless-optoelectrodes-with-on-board-light-sources-for-neural-stimulation-and-recording
#10
K Kampasi, J Seymour, E Stark, G Buzsaki, K D Wise, E Yoon
Fiberless optoelectrodes are an emerging tool to enable brain circuit mapping by providing precise optical modulation and electrical monitoring of many neurons. While optoelectrodes having an on-board light source offer compact and optically efficient device solutions, many of them fail to provide robust thermal and electrical design to fully exploit the recording capabilities of the device. In this work, we present a novel fiberless multicolor optoelectrode solution, which meets the optical and thermal design requirements of an in vivo neural optoelectrode and offers potential for low-noise neural recording...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28256618/the-expanding-family-of-natural-anion-channelrhodopsins-reveals-large-variations-in-kinetics-conductance-and-spectral-sensitivity
#11
Elena G Govorunova, Oleg A Sineshchekov, Elsa M Rodarte, Roger Janz, Olivier Morelle, Michael Melkonian, Gane K-S Wong, John L Spudich
Natural anion channelrhodopsins (ACRs) discovered in the cryptophyte alga Guillardia theta generate large hyperpolarizing currents at membrane potentials above the Nernst equilibrium potential for Cl(-) and thus can be used as efficient inhibitory tools for optogenetics. We have identified and characterized new ACR homologs in different cryptophyte species, showing that all of them are anion-selective, and thus expanded this protein family to 20 functionally confirmed members. Sequence comparison of natural ACRs and engineered Cl(-)-conducting mutants of cation channelrhodopsins (CCRs) showed radical differences in their anion selectivity filters...
March 3, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28256089/striatal-activation-by-optogenetics-induces-dyskinesias-in-the-6-hydroxydopamine-rat-model-of-parkinson-disease
#12
Ledia F Hernández, Ivan Castela, Irene Ruiz-DeDiego, Jose A Obeso, Rosario Moratalla
BACKGROUND: Long-term levodopa (l-dopa) treatment is associated with the development of l-dopa-induced dyskinesias in the majority of patients with Parkinson disease (PD). The etiopathogonesis and mechanisms underlying l-dopa-induced dyskinesias are not well understood. METHODS: We used striatal optogenetic stimulation to induce dyskinesias in a hemiparkinsonian model of PD in rats. Striatal dopamine depletion was induced unilaterally by 6-hydroxydopamine injection into the medial forebrain bundle...
March 3, 2017: Movement Disorders: Official Journal of the Movement Disorder Society
https://www.readbyqxmd.com/read/28255969/-optogenetics-a-therapeutic-option-for-advanced-retinal-dystrophies
#13
A Swiersy, S D Klapper, V Busskamp
Optogenetics refers to the genetic modification of cells to express light-sensitive proteins, which mediate ion flow or secondary signalling cascades upon light exposure. Channelrhodopsin, the most famous example, is an unselective cation channel, which opens when exposed to blue light, thus mediating the depolarisation of the expressing cell. Along with other light-sensitive proteins such as the chloride pump eNpHR, which mediates light-activated hyperpolarisation, the optogenetic toolset offers a wide range of non-invasive single cell manipulations...
March 2, 2017: Klinische Monatsblätter Für Augenheilkunde
https://www.readbyqxmd.com/read/28227507/efficient-assembly-of-multi-color-fiberless-optoelectrodes-with-on-board-light-sources-for-neural-stimulation-and-recording
#14
K Kampasi, J Seymour, E Stark, G Buzsaki, K D Wise, E Yoon, K Kampasi, J Seymour, E Stark, G Buzsaki, K D Wise, E Yoon, E Yoon, K Kampasi, J Seymour, G Buzsaki, E Stark, K D Wise
Fiberless optoelectrodes are an emerging tool to enable brain circuit mapping by providing precise optical modulation and electrical monitoring of many neurons. While optoelectrodes having an on-board light source offer compact and optically efficient device solutions, many of them fail to provide robust thermal and electrical design to fully exploit the recording capabilities of the device. In this work, we present a novel fiberless multicolor optoelectrode solution, which meets the optical and thermal design requirements of an in vivo neural optoelectrode and offers potential for low-noise neural recording...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28225716/divergent-functions-of-the-left-and-right-central-amygdala-in-visceral-nociception
#15
Katelyn E Sadler, Neal A McQuaid, Abigail C Cox, Marissa N Behun, Allison M Trouten, Benedict J Kolber
The left and right central amygdalae (CeA) are limbic regions involved in somatic and visceral pain processing. These 2 nuclei are asymmetrically involved in somatic pain modulation; pain-like responses on both sides of the body are preferentially driven by the right CeA, and in a reciprocal fashion, nociceptive somatic stimuli on both sides of the body predominantly alter molecular and physiological activities in the right CeA. Unknown, however, is whether this lateralization also exists in visceral pain processing and furthermore what function the left CeA has in modulating nociceptive information...
April 2017: Pain
https://www.readbyqxmd.com/read/28216627/layer-specific-optogenetic-activation-of-pyramidal-neurons-causes-beta-gamma-entrainment-of-neonatal-networks
#16
Sebastian H Bitzenhofer, Joachim Ahlbeck, Amy Wolff, J Simon Wiegert, Christine E Gee, Thomas G Oertner, Ileana L Hanganu-Opatz
Coordinated activity patterns in the developing brain may contribute to the wiring of neuronal circuits underlying future behavioural requirements. However, causal evidence for this hypothesis has been difficult to obtain owing to the absence of tools for selective manipulation of oscillations during early development. We established a protocol that combines optogenetics with electrophysiological recordings from neonatal mice in vivo to elucidate the substrate of early network oscillations in the prefrontal cortex...
February 20, 2017: Nature Communications
https://www.readbyqxmd.com/read/28192090/optogenetic-control-of-ca-2-and-voltage-dependent-large-conductance-bk-potassium-channels
#17
Thomas Mager, Phillip G Wood, Ernst Bamberg
Ca(2+) concentration jumps for the activation of Ca(2+)-dependent ion channels or transporters can be obtained either by fast solution exchange or by the use of caged Ca(2+). Here, we report on an alternate optogenetic method for the activation of Ca(2+) and voltage-dependent large conductance (BK) potassium channels. This was achieved through the use of the light-gated channelrhodopsin 2 variant, CatCh(Calcium translocating Channelrhodopsin) with enhanced Ca, which produces locally [Ca(2+)] in the μM range on the inner side of the membrane, without significant [Ca(2+)] increase in the cytosol...
February 10, 2017: Journal of Molecular Biology
https://www.readbyqxmd.com/read/28177213/characterization-of-optically-and-electrically-evoked-dopamine-release-in-striatal-slices-from-digenic-knock-in-mice-with-dat-driven-expression-of-channelrhodopsin
#18
Brian O'Neill, Jyoti C Patel, Margaret E Rice
Fast-scan cyclic voltammetry (FCV) is an established method to monitor increases in extracellular dopamine (DA) concentration ([DA]o) in the striatum, which is densely innervated by DA axons. Ex vivo brain slice preparations provide an opportunity to identify endogenous modulators of DA release. For these experiments, local electrical stimulation is often used to elicit release of DA, as well as other transmitters, in the striatal microcircuitry; changes in evoked increases in [DA]o after application of a pharmacological agent (e...
February 15, 2017: ACS Chemical Neuroscience
https://www.readbyqxmd.com/read/28162892/fast-camp-modulation-of-neurotransmission-via-neuropeptide-signals-and-vesicle-loading
#19
Wagner Steuer Costa, Szi-Chieh Yu, Jana F Liewald, Alexander Gottschalk
Cyclic AMP (cAMP) signaling augments synaptic transmission, but because many targets of cAMP and protein kinase A (PKA) may be involved, mechanisms underlying this pathway remain unclear. To probe this mechanism, we used optogenetic stimulation of cAMP signaling by Beggiatoa-photoactivated adenylyl cyclase (bPAC) in Caenorhabditis elegans motor neurons. Behavioral, electron microscopy (EM), and electrophysiology analyses revealed cAMP effects on both the rate and on quantal size of transmitter release and led to the identification of a neuropeptidergic pathway affecting quantal size...
February 20, 2017: Current Biology: CB
https://www.readbyqxmd.com/read/28159808/optogenetic-identification-of-hypothalamic-orexin-neuron-projections-to-paraventricular-spinally-projecting-neurons
#20
Olga Dergacheva, Akihiro Yamanaka, Alan R Schwartz, Vsevolod Y Polotsky, David Mendelowitz
Orexin neurons, and activation of orexin receptors, are generally thought to be sympathoexcitatory; however, the functional connectivity between orexin neurons and a likely sympathetic target, the hypothalamic spinally-projecting neurons (SPNs) in the paraventricular nucleus of the hypothalamus (PVN), has not been established. To test the hypothesis that orexin neurons project directly to SPNs in the PVN, channelrhodopsin-2 (ChR2) was selectively expressed in orexin neurons to enable photoactivation of ChR2-expressing fibers while examining evoked postsynaptic currents in SPNs in rat hypothalamic slices...
February 3, 2017: American Journal of Physiology. Heart and Circulatory Physiology
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