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https://www.readbyqxmd.com/read/29674962/invaginating-structures-in-mammalian-synapses
#1
REVIEW
Ronald S Petralia, Ya-Xian Wang, Mark P Mattson, Pamela J Yao
Invaginating structures at chemical synapses in the mammalian nervous system exist in presynaptic axon terminals, postsynaptic spines or dendrites, and glial processes. These invaginating structures can be divided into three categories. The first category includes slender protrusions invaginating into axonal terminals, postsynaptic spines, or glial processes. Best known examples of this category are spinules extending from postsynaptic spines into presynaptic terminals in forebrain synapses. Another example of this category are protrusions from inhibitory presynaptic terminals invaginating into postsynaptic neuronal somas...
2018: Frontiers in Synaptic Neuroscience
https://www.readbyqxmd.com/read/29667170/cone-synapses-in-mammalian-retinal-rod-bipolar-cells
#2
Ji-Jie Pang, Zhuo Yang, Roy A Jacoby, Samuel M Wu
Some mammalian rod bipolar cells (RBCs) can receive excitatory chemical synaptic inputs from both rods and cones (DBCR2 ), but anatomical evidence for mammalian cone-RBC contacts has been sparse. We examined anatomical cone-RBC contacts using neurobiotin (NB) to visualize individual mouse cones and standard immuno-markers to identify RBCs, cone pedicles and synapses in mouse and baboon retinas. Peanut agglutinin (PNA) stained the basal membrane of all cone pedicles, and mouse cones were positive for red/green (R/G)-opsin, whereas baboon cones were positive for calbindin D-28k...
April 18, 2018: Journal of Comparative Neurology
https://www.readbyqxmd.com/read/29659572/a-computational-study-of-astrocytic-glutamate-influence-on-post-synaptic-neuronal-excitability
#3
Bronac Flanagan, Liam McDaid, John Wade, KongFatt Wong-Lin, Jim Harkin
The ability of astrocytes to rapidly clear synaptic glutamate and purposefully release the excitatory transmitter is critical in the functioning of synapses and neuronal circuits. Dysfunctions of these homeostatic functions have been implicated in the pathology of brain disorders such as mesial temporal lobe epilepsy. However, the reasons for these dysfunctions are not clear from experimental data and computational models have been developed to provide further understanding of the implications of glutamate clearance from the extracellular space, as a result of EAAT2 downregulation: although they only partially account for the glutamate clearance process...
April 16, 2018: PLoS Computational Biology
https://www.readbyqxmd.com/read/29651235/selective-labeling-of-individual-neurons-in-dense-cultured-networks-with-nanoparticle-enhanced-photoporation
#4
Ranhua Xiong, Peter Verstraelen, Jo Demeester, Andre G Skirtach, Jean-Pierre Timmermans, Stefaan C De Smedt, Winnok H De Vos, Kevin Braeckmans
Neurodevelopmental and neurodegenerative disorders are characterized by subtle alterations in synaptic connections and perturbed neuronal network functionality. A hallmark of neuronal connectivity is the presence of dendritic spines, micron-sized protrusions of the dendritic shaft that compartmentalize single synapses to fine-tune synaptic strength. However, accurate quantification of spine density and morphology in mature neuronal networks is hampered by the lack of targeted labeling strategies. To resolve this, we have optimized a method to deliver cell-impermeable compounds into selected cells based on Spatially resolved NAnoparticle-enhanced Photoporation (SNAP)...
2018: Frontiers in Cellular Neuroscience
https://www.readbyqxmd.com/read/29620843/biofunctionalized-3d-nanopillar-arrays-fostering-cell-guidance-and-promoting-synapse-stability-and-neuronal-activity-in-networks
#5
Hayder Amin, Michele Dipalo, Francesco De Angelis, Luca Berdondini
A controlled geometry of in vitro neuronal networks allows investigation of the cellular mechanisms that underlie neuron-to-neuron and neuron-extracellular matrix interactions, which are essential to biomedical research. Herein, we report a selective guidance of primary hippocampal neurons by using arrays of three-dimensional vertical nanopillars (NPs) functionalized with a specific adhesion-promoting molecule-poly-dl-ornithine (PDLO). We show that 90% of neuronal cells are guided exclusively on the combinatorial PDLO/NP substrate...
April 17, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29619614/tnf%C3%AE-and-il-1%C3%AE-but-not-il-18-suppresses-hippocampal-long-term-potentiation-directly-at-the-synapse
#6
G Aleph Prieto, Liqi Tong, Erica D Smith, Carl W Cotman
CNS inflammatory responses are linked to cognitive impairment in humans. Research in animal models supports this connection by showing that inflammatory cytokines suppress long-term potentiation (LTP), the best-known cellular correlate of memory. Cytokine-induced modulation of LTP has been previously studied in vivo or in brain slices, two experimental approaches containing multiple cell populations responsive to cytokines. In their target cells, cytokines commonly increase the expression of multiple cytokines, thus increasing the complexity of brain cytokine networks even after single-cytokine challenges...
April 4, 2018: Neurochemical Research
https://www.readbyqxmd.com/read/29615922/sensory-processing-and-integration-at-the-carotid-body-tripartite-synapse-neurotransmitter-functions-and-effects-of-chronic-hypoxia
#7
REVIEW
Erin M Leonard, Shaima Salman, Colin A Nurse
Maintenance of homeostasis in the respiratory and cardiovascular systems depends on reflexes that are initiated at specialized peripheral chemoreceptors that sense changes in the chemical composition of arterial blood. In mammals, the bilaterally-paired carotid bodies (CBs) are the main peripheral chemoreceptor organs that are richly vascularized and are strategically located at the carotid bifurcation. The CBs contribute to the maintenance of O2 , CO2 /H+ , and glucose homeostasis and have attracted much clinical interest because hyperactivity in these organs is associated with several pathophysiological conditions including sleep apnea, obstructive lung disease, heart failure, hypertension, and diabetes...
2018: Frontiers in Physiology
https://www.readbyqxmd.com/read/29587245/mitochondrial-ros-cause-motor-deficits-induced-by-synaptic-inactivity-implications-for-synapse-pruning
#8
Eva Sidlauskaite, Jack W Gibson, Ian L Megson, Philip D Whitfield, Artak Tovmasyan, Ines Batinic-Haberle, Michael P Murphy, Peter R Moult, James N Cobley
Developmental synapse pruning refines burgeoning connectomes. The basic mechanisms of mitochondrial reactive oxygen species (ROS) production suggest they select inactive synapses for pruning: whether they do so is unknown. To begin to unravel whether mitochondrial ROS regulate pruning, we made the local consequences of neuromuscular junction (NMJ) pruning detectable as motor deficits by using disparate exogenous and endogenous models to induce synaptic inactivity en masse in developing Xenopus laevis tadpoles...
March 20, 2018: Redox Biology
https://www.readbyqxmd.com/read/29572431/a-gain-of-function-mutation-in-the-%C3%AE-9-nicotinic-acetylcholine-receptor-alters-medial-olivocochlear-efferent-short-term-synaptic-plasticity
#9
Carolina Wedemeyer, Lucas G Vattino, Marcelo J Moglie, Jimena Ballestero, Stéphane F Maison, Mariano N Di Guilmi, Julian Taranda, M Charles Liberman, Paul A Fuchs, Eleonora Katz, Ana Belén Elgoyhen
Gain control of the auditory system operates at multiple levels. Cholinergic medial olivocochlear (MOC) fibers originate in the brainstem and make synaptic contacts at the base of the outer hair cells (OHCs), the final targets of several feedback loops from the periphery and higher processing centers. Efferent activation inhibits OHC active amplification within the mammalian cochlea, through the activation of a calcium permeable α9α10 ionotropic cholinergic nicotinic receptor (nAChR), functionally coupled to calcium activated SK2 potassium channels...
March 23, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/29563180/variations-in-ca-2-influx-can-alter-ca-2-chelator-based-estimates-of-ca-2-channel-synaptic-vesicle-coupling-distance
#10
Yukihiro Nakamura, Maria Reva, David A DiGregorio
The timing and probability of synaptic vesicle fusion from presynaptic terminals is governed by the strength of coupling between voltage-gated Ca2+ channels (VGCCs) and Ca2+ sensors for exocytosis. This VGCC-sensor coupling distance can be estimated from the fractional block of vesicular release by exogenous Ca2+ chelators. However, estimates of this distance can depend on many biophysical factors, whose contributions have not been thoroughly explored. Using numerical simulations of Ca2+ reaction and diffusion, as well as vesicular release, we examined the contributions of conductance, density, and open duration of VGCCs, as well as the influence of endogenous Ca2+ buffers on the inhibition of exocytosis by EGTA...
March 21, 2018: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/29559501/synaptogenesis-is-modulated-by-heparan-sulfate-in-caenorhabditis-elegans
#11
María Lázaro-Peña, Carlos Díaz-Balzac, Hannes Bülow, Scott Emmons
The nervous system regulates complex behaviors through a network of neurons interconnected by synapses. How specific synaptic connections are genetically determined is still unclear. Male mating is the most complex behavior in C. elegans It is composed of sequential steps that are governed by more than 3,000 chemical connections. Here we show that heparan sulfates (HS) play a role in the formation and function of the male neural network. HS, sulfated in position 3 by the HS modification enzyme HST-3.1 / HS 3- O -sulfotransferase and attached to the HSPG glypicans LON-2/glypican and GPN-1/glypican, functions cell-autonomously and non-autonomously for response to hermaphrodite contact during mating...
March 20, 2018: Genetics
https://www.readbyqxmd.com/read/29557634/spatial-and-chemical-surface-guidance-of-nk-cell-cytotoxic-activity
#12
Guillaume Le Saux, Avishay Edri, Yossi Keydar, Uzi Hadad, Angel Porgador, Mark Schvartzman
Studying of how different signaling pathways spatially integrate in cells requires selective manipulation and control of different transmembrane ligand-receptor pairs at the same time. This work explores a novel method for precisely arranging two arbitrarily chosen ligands on a micron-scale 2D pattern. The approach is based on lithographic patterning of Au and TiO2 films, followed by their selective functionalization with Ni-NTA/histidine and biotin/avidin chemistries, respectively. The selectivity of chemical and biological functionalizations is demonstrated by XPS and immunofluorescence imaging, respectively...
March 20, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29544505/superresolution-fluorescence-microscopy-for-3d-reconstruction-of-thick-samples
#13
Sangjun Park, Wooyoung Kang, Yeong-Dae Kwon, Jaehoon Shim, Siyong Kim, Bong-Kiun Kaang, Sungchul Hohng
Three-dimensional (3D) reconstruction of thick samples using superresolution fluorescence microscopy remains challenging due to high level of background noise and fast photobleaching of fluorescence probes. We develop superresolution fluorescence microscopy that can reconstruct 3D structures of thick samples with both high localization accuracy and no photobleaching problem. The background noise is reduced by optically sectioning the sample using line-scan confocal microscopy, and the photobleaching problem is overcome by using the DNA-PAINT (Point Accumulation for Imaging in Nanoscale Topography)...
March 15, 2018: Molecular Brain
https://www.readbyqxmd.com/read/29529034/gap-junction-plasticity-as-a-mechanism-to-regulate-network-wide-oscillations
#14
Guillaume Pernelle, Wilten Nicola, Claudia Clopath
Cortical oscillations are thought to be involved in many cognitive functions and processes. Several mechanisms have been proposed to regulate oscillations. One prominent but understudied mechanism is gap junction coupling. Gap junctions are ubiquitous in cortex between GABAergic interneurons. Moreover, recent experiments indicate their strength can be modified in an activity-dependent manner, similar to chemical synapses. We hypothesized that activity-dependent gap junction plasticity acts as a mechanism to regulate oscillations in the cortex...
March 12, 2018: PLoS Computational Biology
https://www.readbyqxmd.com/read/29526716/inhibition-of-protein-tyrosine-phosphatase-1b-in-spinal-cord-dorsal-horn-of-rats-attenuated-diabetic-neuropathic-pain
#15
Ji-Yuan Zhao, Li Yang, Hu-Hu Bai, Jiang-Ping Liu, Zhan-Wei Suo, Xian Yang, Xiao-Dong Hu
Protein tyrosine phosphatase 1B (PTP1B) has been shown to dephosphorylate and inactivate insulin receptors, which contributes to the pathogenesis of diabetes. Neuropathic pain is one of the severe complications that results from diabetic neuropathy. However, whether PTP1B was involved in the development of diabetic neuropathic pain is largely unknown. The current study illustrated that PTP1B was located in spinal cord dorsal horn neurons of Sprague-Dawley rats. Western blot analysis demonstrated that the diabetic neuropathic pain induced by intraperitoneal injection of streptozotocin was associated with an increased protein expression and a dynamic redistribution of spinal PTP1B into excitatory glutamatergic synapses...
March 8, 2018: European Journal of Pharmacology
https://www.readbyqxmd.com/read/29501892/in-vivo-spatiotemporal-dynamics-of-ng2-glia-activity-caused-by-neural-electrode-implantation
#16
Steven M Wellman, Takashi D Y Kozai
Neural interface technology provides direct sampling and analysis of electrical and chemical events in the brain in order to better understand neuronal function and treat neurodegenerative disease. However, intracortical electrodes experience inflammatory reactions that reduce long-term stability and functionality and are understood to be facilitated by activated microglia and astrocytes. Emerging studies have identified another cell type that participates in the formation of a high-impedance glial scar following brain injury; the oligodendrocyte precursor cell (OPC)...
February 20, 2018: Biomaterials
https://www.readbyqxmd.com/read/29497465/piezoelectric-smart-biomaterials-for-bone-and-cartilage-tissue-engineering
#17
REVIEW
Jaicy Jacob, Namdev More, Kiran Kalia, Govinda Kapusetti
Tissues like bone and cartilage are remodeled dynamically for their functional requirements by signaling pathways. The signals are controlled by the cells and extracellular matrix and transmitted through an electrical and chemical synapse. Scaffold-based tissue engineering therapies largely disturb the natural signaling pathways, due to their rigidity towards signal conduction, despite their therapeutic advantages. Thus, there is a high need of smart biomaterials, which can conveniently generate and transfer the bioelectric signals analogous to native tissues for appropriate physiological functions...
2018: Inflammation and Regeneration
https://www.readbyqxmd.com/read/29463281/soluble-a%C3%AE-1-42-increases-the-heterogeneity-in-synaptic-vesicle-pool-size-among-synapses-by-suppressing-intersynaptic-vesicle-sharing
#18
Daehun Park, Sunghoe Chang
Growing evidence has indicated that prefibrillar form of soluble amyloid beta (sAβ1-42 ) is the major causative factor in the synaptic dysfunction associated with AD. The molecular changes leading to presynaptic dysfunction caused by sAβ1-42 , however, still remains elusive. Recently, we found that sAβ1-42 inhibits chemically induced long-term potentiation-induced synaptogenesis by suppressing the intersynaptic vesicle trafficking through calcium (Ca2+ ) dependent hyperphosphorylation of synapsin and CaMKIV...
February 20, 2018: Molecular Brain
https://www.readbyqxmd.com/read/29443098/a-novel-in-vitro-live-imaging-assay-of-astrocyte-mediated-phagocytosis-using-ph-indicator-conjugated-synaptosomes
#19
Youkyeong Gloria Byun, Won-Suk Chung
Astrocytes are the major cell type in the brain and directly contact synapses and blood vessels. Although microglial cells have been considered the major immune cells and only phagocytes in the brain, recent studies have shown that astrocytes also participate in various phagocytic processes, such as developmental synapse elimination and clearance of amyloid beta plaques in Alzheimer's disease (AD). Despite these findings, the efficiency of astrocyte engulfment and degradation of their targets is unclear compared with that of microglia...
February 5, 2018: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/29431275/burst-spinal-cord-stimulation-review-of-preclinical-studies-and-comments-on-clinical-outcomes
#20
REVIEW
Krishnan Chakravarthy, Alexander R Kent, Adil Raza, Fang Xing, Thomas M Kinfe
BACKGROUND: Burst spinal cord stimulation (SCS) technology uses a novel waveform that consists of closely packed high-frequency electrical impulses followed by a quiescent period. Within the growing field of neuromodulation, burst stimulation is unique in that it mimics the natural burst firing of the nervous system, in particular the thalamo-cingulate rhythmicity, resulting in modulation of the affective and attentional components of pain processing (e.g., medial thalamic pathways). STUDY DESIGN: A review of preclinical and clinical studies regarding burst SCS for various chronic pain states...
February 12, 2018: Neuromodulation: Journal of the International Neuromodulation Society
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