keyword
MENU ▼
Read by QxMD icon Read
search

axon initial segment

keyword
https://www.readbyqxmd.com/read/28734032/characterization-of-the-axon-initial-segment-of-mice-substantia-nigra-dopaminergic-neurons
#1
Cristian González-Cabrera, Rodrigo Meza, Lorena Ulloa, Paulina Merino-Sepúlveda, Valentina Luco, Ana Sanhueza, Alejandro Oñate-Ponce, J Paul Bolam, Pablo Henny
The axon initial segment (AIS) is the site of initiation of action potentials and also influences action potential waveform, firing pattern and rate. In view of the fundamental aspects of motor function and behavior that depend on the firing of substantia nigra pars compacta (SNc) dopaminergic neurons, we identified and characterized their AIS in the mouse. Immunostaining for tyrosine hydroxylase (TH), sodium channels (Nav ) and ankyrin-G (Ank-G) was used to visualize the AIS of dopaminergic neurons. Reconstructions of sampled AIS of dopaminergic neurons revealed variable lengths (12 - 60 μm) and diameters (0...
July 22, 2017: Journal of Comparative Neurology
https://www.readbyqxmd.com/read/28713955/altered-axon-initial-segment-in-hippocampal-newborn-neurons-associated-with-recurrence-of-temporal-lobe-epilepsy-in-rats
#2
Tian-Tian Liu, Li Feng, Heng-Fang Liu, Yi Shu, Bo Xiao
Hippocampal neurogenesis in temporal lobe epilepsy (TLE) may result in alteration of the excitability of neurons, which contributes to spontaneous recurrent seizures. Axon initial segment (AIS) structural and functional plasticity is important in the control of neuronal excitability. It remains to be elucidated whether the plasticity of AIS occurs in hippocampal newly‑generated neurons that are involved in recurrent seizures following pilocarpine‑induced status epilepticus (SE). The present study first established a pilocarpine‑induced TLE rat model to assess the features of newborn neurons and AIS plasticity alterations using double immunofluorescence staining of Ankyrin G and doublecortin (DCX)...
September 2017: Molecular Medicine Reports
https://www.readbyqxmd.com/read/28709993/intracellular-calcium-release-through-ip3r-or-ryr-contributes-to-secondary-axonal-degeneration
#3
Ben C Orem, Nicolas Pelisch, Joshua Williams, Jacqueline M Nally, David P Stirling
Severed CNS axons often retract or dieback away from the injury site and fail to regenerate. The precise mechanisms underlying acute axonal dieback and secondary axonal degeneration remain poorly understood. Here we investigate the role of Ca(2+) store mediated intra-axonal Ca(2+) release in acute axonal dieback and secondary axonal degeneration. To differentiate between primary (directly transected) and "bystander" axonal injury (axons spared by the initial injury but then succumb to secondary degeneration) in real-time we use our previously published highly focal laser-induced spinal cord injury (LiSCI) ex vivo model...
July 12, 2017: Neurobiology of Disease
https://www.readbyqxmd.com/read/28683314/periadolescent-maturation-of-gabaergic-hyperpolarization-at-the-axon-initial-segment
#4
Gina Rinetti-Vargas, Khanhky Phamluong, Dorit Ron, Kevin J Bender
Neuronal chloride levels are developmentally regulated. Early in life, high intracellular concentrations support chloride efflux and depolarization at GABAergic synapses. In mouse, intracellular chloride decreases over the first postnatal week in the somatodendritic compartment, eventually supporting mature, hyperpolarizing GABAergic inhibition. In contrast to this dendritic switch, it is less clear how GABAergic signaling at the axon initial segment (AIS) functions in mature pyramidal cells, as reports of both depolarization and hyperpolarization have been reported in the AIS past the first postnatal week...
July 5, 2017: Cell Reports
https://www.readbyqxmd.com/read/28673977/lgi1-tunes-intrinsic-excitability-by-regulating-the-density-of-axonal-kv1-channels
#5
Michael Seagar, Michael Russier, Olivier Caillard, Yves Maulet, Laure Fronzaroli-Molinieres, Marina De San Feliciano, Norah Boumedine-Guignon, Léa Rodriguez, Mickael Zbili, Fabrice Usseglio, Christine Formisano-Tréziny, Fahamoe Youssouf, Marion Sangiardi, Morgane Boillot, Stéphanie Baulac, María José Benitez, Juan-José Garrido, Dominique Debanne, Oussama El Far
Autosomal dominant epilepsy with auditory features results from mutations in leucine-rich glioma-inactivated 1 (LGI1), a soluble glycoprotein secreted by neurons. Animal models of LGI1 depletion display spontaneous seizures, however, the function of LGI1 and the mechanisms by which deficiency leads to epilepsy are unknown. We investigated the effects of pure recombinant LGI1 and genetic depletion on intrinsic excitability, in the absence of synaptic input, in hippocampal CA3 neurons, a classical focus for epileptogenesis...
July 3, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28643105/differential-role-of-gabaa-receptors-and-neuroligin-2-for-perisomatic-gabaergic-synapse-formation-in-the-hippocampus
#6
Patrizia Panzanelli, Simon Früh, Jean-Marc Fritschy
Perisomatic GABAergic synapses onto hippocampal pyramidal cells arise from two populations of basket cells with different neurochemical and functional properties. The presence of the dystrophin-glycoprotein complex in their postsynaptic density (PSD) distinguishes perisomatic synapses from GABAergic synapses on dendrites and the axon-initial segment. Targeted deletion of neuroligin 2 (NL2), a transmembrane protein interacting with presynaptic neurexin, has been reported to disrupt postsynaptic clustering of GABAA receptors (GABAAR) and their anchoring protein, gephyrin, at perisomatic synapses...
June 22, 2017: Brain Structure & Function
https://www.readbyqxmd.com/read/28634442/mild-traumatic-brain-injury-evokes-pyramidal-neuron-axon-initial-segment-plasticity-and-diffuse-presynaptic-inhibitory-terminal-loss
#7
Michal Vascak, Jianli Sun, Matthew Baer, Kimberle M Jacobs, John T Povlishock
The axon initial segment (AIS) is the site of action potential (AP) initiation, thus a crucial regulator of neuronal activity. In excitatory pyramidal neurons, the high density of voltage-gated sodium channels (NaV1.6) at the distal AIS regulates AP initiation. A surrogate AIS marker, ankyrin-G (ankG) is a structural protein regulating neuronal functional via clustering voltage-gated ion channels. In neuronal circuits, changes in presynaptic input can alter postsynaptic output via AIS structural-functional plasticity...
2017: Frontiers in Cellular Neuroscience
https://www.readbyqxmd.com/read/28624616/age-related-plasticity-of-the-axon-initial-segment-of-cortical-pyramidal-cells-in-marmoset-monkeys
#8
Nafiseh Atapour, Marcello G P Rosa
Structural plasticity of the axon initial segment (AIS), the site of action potential initiation, is observed as part of the normal early development of the cortex, as well as in association with injury and disease. Here, we show that structural AIS plasticity also occurs with normal aging in adult marmosets. Immunohistochemical techniques were used to reveal the extent of the AIS of layer 2/3A pyramidal cells in 8 neocortical areas. We found that the AIS length varied significantly between areas in young adult (2-3 years old) marmosets, with neurons in frontal area 14C having the longest AIS, and those in the primary visual cortex the shortest...
May 22, 2017: Neurobiology of Aging
https://www.readbyqxmd.com/read/28612392/linking-activity-dependent-control-of-axon-initial-segment-structure-to-the-cytoskeleton-commentary-on-evans-et-al-2017
#9
Oriol Ros, Xavier Nicol
No abstract text is available yet for this article.
June 14, 2017: European Journal of Neuroscience
https://www.readbyqxmd.com/read/28595650/acute-neuroinflammation-induces-ais-structural-plasticity-in-a-nox2-dependent-manner
#10
S D Benusa, N M George, B A Sword, G H DeVries, J L Dupree
BACKGROUND: Chronic microglia-mediated inflammation and oxidative stress are well-characterized underlying factors in neurodegenerative disease, whereby reactive inflammatory microglia enhance ROS production and impact neuronal integrity. Recently, it has been shown that during chronic inflammation, neuronal integrity is compromised through targeted disruption of the axon initial segment (AIS), the axonal domain critical for action potential initiation. AIS disruption was associated with contact by reactive inflammatory microglia which wrap around the AIS, increasing association with disease progression...
June 8, 2017: Journal of Neuroinflammation
https://www.readbyqxmd.com/read/28584914/optical-coherence-tomography-for-the-diagnosis-and-monitoring-of-idiopathic-intracranial-hypertension
#11
Philipp Albrecht, Christine Blasberg, Marius Ringelstein, Ann-Kristin Müller, David Finis, Rainer Guthoff, Ella-Maria Kadas, Wolf Lagreze, Orhan Aktas, Hans-Peter Hartung, Friedemann Paul, Alexander U Brandt, Axel Methner
The objectives of the study were to investigate the value of optical coherence tomography in detecting papilledema in patients with idiopathic intracranial hypertension (IIH), a disease which is difficult to monitor and which can lead to permanent visual deficits; to analyze retinal changes over time. In this non-interventional case-control study, spectral-domain optical coherence tomography (SD-OCT) was used to analyze the retinal and optic nerve head (ONH) morphology of 21 patients with IIH and 27 age- and sex-matched healthy controls over time...
July 2017: Journal of Neurology
https://www.readbyqxmd.com/read/28584877/neocortical-chandelier-cells-developmentally-shape-axonal-arbors-through-reorganization-but-establish-subcellular-synapse-specificity-without-refinement
#12
André Steinecke, Ellie Hozhabri, Stephen Tapanes, Yugo Ishino, Hongkui Zeng, Naomi Kamasawa, Hiroki Taniguchi
Diverse types of cortical interneurons (INs) mediate various kinds of inhibitory control mechanisms to balance and shape network activity. Distinct IN subtypes develop uniquely organized axonal arbors that innervate different subcellular compartments of excitatory principal neurons (PNs), which critically contribute to determining their output properties. However, it remains poorly understood how they establish this peculiar axonal organization and synaptic connectivity during development. Here, taking advantage of genetic labeling of IN progenitors, we examined developmental processes of axonal arbors and synaptic connections formed by murine chandelier cells (ChCs), which innervate axon initial segments (AISs) of PNs and thus powerfully regulate their spike generation...
May 2017: ENeuro
https://www.readbyqxmd.com/read/28572759/dendritic-actin-cytoskeleton-structure-functions-and-regulations
#13
REVIEW
Anja Konietzny, Julia Bär, Marina Mikhaylova
Actin is a versatile and ubiquitous cytoskeletal protein that plays a major role in both the establishment and the maintenance of neuronal polarity. For a long time, the most prominent roles that were attributed to actin in neurons were the movement of growth cones, polarized cargo sorting at the axon initial segment, and the dynamic plasticity of dendritic spines, since those compartments contain large accumulations of actin filaments (F-actin) that can be readily visualized using electron- and fluorescence microscopy...
2017: Frontiers in Cellular Neuroscience
https://www.readbyqxmd.com/read/28536506/axonal-membranes-and-their-domains-assembly-and-function-of-the-axon-initial-segment-and-node-of-ranvier
#14
REVIEW
Andrew D Nelson, Paul M Jenkins
Neurons are highly specialized cells of the nervous system that receive, process and transmit electrical signals critical for normal brain function. Here, we review the intricate organization of axonal membrane domains that facilitate rapid action potential conduction underlying communication between complex neuronal circuits. Two critical excitable domains of vertebrate axons are the axon initial segment (AIS) and the nodes of Ranvier, which are characterized by the high concentrations of voltage-gated ion channels, cell adhesion molecules and specialized cytoskeletal networks...
2017: Frontiers in Cellular Neuroscience
https://www.readbyqxmd.com/read/28536263/axodendritic-sorting-and-pathological-missorting-of-tau-is-isoform-specific-and-determined-by-axon-initial-segment-architecture
#15
Hans Zempel, Frank Dennissen, Yatender Kumar, Julia Luedtke, Jacek Biernat, Eva-Maria Mandelkow, Eckhard Mandelkow
Subcellular mislocalization of the microtubule-associated protein Tau is a hallmark of Alzheimer disease (AD) and other tauopathies. Six Tau isoforms, differentiated by the presence or absence of a second repeat or of N-terminal inserts, exist in the human CNS but their physiological and pathological differences have long remained remain elusive. Here, we investigated the properties and distributions of human and rodent Tau isoforms in primary forebrain rodent neurons. We found that the Tau-Diffusion-Barrier (TDB), located within the Axon-Initial-Segment (AIS), controls retrograde (axon-to-soma) and anterograde (soma-to-axon) traffic of Tau...
May 23, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28534438/the-axonal-cytoskeleton-and-the-assembly-of-nodes-of-ranvier
#16
Aniket Ghosh, Diane L Sherman, Peter J Brophy
Vertebrate nervous systems rely on rapid nerve impulse transmission to support their complex functions. Fast conduction depends on ensheathment of nerve axons by myelin-forming glia and the clustering of high concentrations of voltage-gated sodium channels (Nav) in the axonal gaps between myelinated segments. These gaps are the nodes of Ranvier. Depolarization of the axonal membrane initiates the action potential responsible for impulse transmission, and the Nav help ensure that this is restricted to nodes...
May 1, 2017: Neuroscientist: a Review Journal Bringing Neurobiology, Neurology and Psychiatry
https://www.readbyqxmd.com/read/28533267/the-kv1-associated-molecules-tag-1-and-caspr2-are-selectively-targeted-to-the-axon-initial-segment-in-hippocampal-neurons
#17
Delphine Pinatel, Bruno Hivert, Margaux Saint-Martin, Nelly Noraz, Maria Savvaki, Domna Karagogeos, Catherine Faivre-Sarrailh
Caspr2 and TAG-1 (also known as CNTNAP2 and CNTN2, respectively) are cell adhesion molecules (CAMs) associated with the voltage-gated potassium channels Kv1.1 and Kv1.2 (also known as KCNA1 and KCNA2, respectively) at regions controlling axonal excitability, namely, the axon initial segment (AIS) and juxtaparanodes of myelinated axons. The distribution of Kv1 at juxtaparanodes requires axo-glial contacts mediated by Caspr2 and TAG-1. In the present study, we found that TAG-1 strongly colocalizes with Kv1.2 at the AIS of cultured hippocampal neurons, whereas Caspr2 is uniformly expressed along the axolemma...
July 1, 2017: Journal of Cell Science
https://www.readbyqxmd.com/read/28522735/d3-receptors-regulate-excitability-in-a-unique-class-of-prefrontal-pyramidal-cells
#18
Rebecca L Clarkson, Alayna T Liptak, Steven M Gee, Vikaas S Sohal, Kevin J Bender
The D3 dopamine receptor, a member of the Gi-coupled D2 family of dopamine receptors, is expressed throughout limbic circuits affected in neuropsychiatric disorders, including prefrontal cortex (PFC). These receptors are important for prefrontal executive function because pharmacological and genetic manipulations that affect prefrontal D3 receptors alter anxiety, social interaction, and reversal learning. However, the mechanisms by which D3 receptors regulate prefrontal circuits and whether D3 receptors regulate specific prefrontal subnetworks remains unknown...
June 14, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28469558/intracellular-fibroblast-growth-factor-14-emerging-risk-factor-for-brain-disorders
#19
REVIEW
Jessica Di Re, Paul A Wadsworth, Fernanda Laezza
The finely tuned regulation of neuronal firing relies on the integrity of ion channel macromolecular complexes. Minimal disturbances of these tightly regulated networks can lead to persistent maladaptive plasticity of brain circuitry. The intracellular fibroblast growth factor 14 (FGF14) belongs to the nexus of proteins interacting with voltage-gated Na+ (Nav) channels at the axonal initial segment. Through isoform-specific interactions with the intracellular C-terminal tail of neuronal Nav channels (Nav1.1, Nav1...
2017: Frontiers in Cellular Neuroscience
https://www.readbyqxmd.com/read/28452088/myosin-ii-activity-is-required-for-structural-plasticity-at-the-axon-initial-segment
#20
Mark D Evans, Candida Tufo, Adna S Dumitrescu, Matthew S Grubb
In neurons, axons possess a molecularly defined and highly organised proximal region - the axon initial segment (AIS) - that is a key regulator of both electrical excitability and cellular polarity. Despite existing as a large, dense structure with specialised cytoskeletal architecture, the AIS is surprisingly plastic, with sustained alterations in neuronal activity bringing about significant alterations to its position, length or molecular composition. However, although the upstream activity-dependent signalling pathways that lead to such plasticity have begun to be elucidated, the downstream mechanisms that produce structural changes at the AIS are completely unknown...
April 27, 2017: European Journal of Neuroscience
keyword
keyword
52538
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"