scholarly journals Expression, Cellular and Subcellular Localisation of Kv4.2 and Kv4.3 Channels in the Rodent Hippocampus

2019 ◽  
Vol 20 (2) ◽  
pp. 246 ◽  
Author(s):  
Rocío Alfaro-Ruíz ◽  
Carolina Aguado ◽  
Alejandro Martín-Belmonte ◽  
Ana Esther Moreno-Martínez ◽  
Rafael Luján
Keyword(s):  
Plasma Membrane ◽  
Hippocampal Neurons ◽  
Granule Cells ◽  
Regional Distribution ◽  
Distribution Patterns ◽  
Adult Brain ◽  
Subcellular Localisation ◽  
Similar Distribution ◽  
Principal Cells ◽  
Development Levels

The Kv4 family of voltage-gated K+ channels underlie the fast transient (A-type) outward K+ current. Although A-type currents are critical to determine somato-dendritic integration in central neurons, relatively little is known about the precise subcellular localisation of the underlying channels in hippocampal circuits. Using histoblot and immunoelectron microscopic techniques, we investigated the expression, regional distribution and subcellular localisation of Kv4.2 and Kv4.3 in the adult brain, as well as the ontogeny of their expression during postnatal development. Histoblot demonstrated that Kv4.2 and Kv4.3 proteins were widely expressed in the brain, with mostly non-overlapping patterns. During development, levels of Kv4.2 and Kv4.3 increased with age but showed marked region- and developmental stage-specific differences. Immunoelectron microscopy showed that labelling for Kv4.2 and Kv4.3 was differentially present in somato-dendritic domains of hippocampal principal cells and interneurons, including the synaptic specialisation. Quantitative analyses indicated that most immunoparticles for Kv4.2 and Kv4.3 were associated with the plasma membrane in dendritic spines and shafts, and that the two channels showed very similar distribution patterns in spines of principal cells and along the surface of granule cells. Our data shed new light on the subcellular localisation of Kv4 channels and provide evidence for their non-uniform distribution over the plasma membrane of hippocampal neurons.

scholarly journals Cellular and Subcellular Localisation of Kv4-Associated KChIP Proteins in the Rat Cerebellum

2020 ◽  
Vol 21 (17) ◽  
pp. 6403
Author(s):  
Rocío Alfaro-Ruíz ◽  
Carolina Aguado ◽  
Alejandro Martín-Belmonte ◽  
Ana Esther Moreno-Martínez ◽  
Rafael Luján
Keyword(s):  
Plasma Membrane ◽  
Purkinje Cells ◽  
Granule Cells ◽  
Distribution Patterns ◽  
Microscopic Level ◽  
Electron Microscopic Level ◽  
K Channel ◽  
Subcellular Localisation ◽  
Electron Microscopic ◽  
Parallel Fibres

The K+ channel interacting proteins (KChIPs) are a family of cytosolic proteins that interact with Kv4 channels, leading to higher current density, modulation of channel inactivation and faster recovery from inactivation. Using immunohistochemical techniques at the light and electron microscopic level combined with quantitative analysis, we investigated the cellular and subcellular localisation of KChIP3 and KChIP4 to compare their distribution patterns with those for Kv4.2 and Kv4.3 in the cerebellar cortex. Immunohistochemistry at the light microscopic level demonstrated that KChIP3, KChIP4, Kv4.2 and Kv4.3 proteins were widely expressed in the cerebellum, with mostly overlapping patterns. Immunoelectron microscopic techniques showed that KChIP3, KChIP4, Kv4.2 and Kv4.3 shared virtually the same somato-dendritic domains of Purkinje cells and granule cells. Application of quantitative approaches showed that KChIP3 and KChIP4 were mainly membrane-associated, but also present at cytoplasmic sites close to the plasma membrane, in dendritic spines and shafts of Purkinje cells (PCs) and dendrites of granule cells (GCs). Similarly, immunoparticles for Kv4.2 and Kv4.3 were observed along the plasma membrane and at intracellular sites in the same neuron populations. In addition to the preferential postsynaptic distribution, KChIPs and Kv4 were also distributed presynaptically in parallel fibres and mossy fibres. Immunoparticles for KChIP3, KChIP4 and Kv4.3 were detected in parallel fibres, and KChIP3, KChIP4, Kv4.2 and Kv4.3 were found in parallel fibres, indicating that composition of KChIP and Kv4 seems to be input-dependent. Together, our findings unravelled previously uncharacterised KChIP and Kv4 subcellular localisation patterns in neurons, revealed that KChIP have additional Kv4-unrelated functions in the cerebellum and support the formation of macromolecular complexes between KChIP3 and KChIP4 with heterotetrameric Kv4.2/Kv4.3 channels.

scholarly journals The Expression and Localisation of G-Protein-Coupled Inwardly Rectifying Potassium (GIRK) Channels Is Differentially Altered in the Hippocampus of Two Mouse Models of Alzheimer’s Disease

2021 ◽  
Vol 22 (20) ◽  
pp. 11106
Author(s):  
Rocío Alfaro-Ruiz ◽  
Alejandro Martín-Belmonte ◽  
Carolina Aguado ◽  
Félix Hernández ◽  
Ana Esther Moreno-Martínez ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Transgenic Mice ◽  
G Protein ◽  
Hippocampal Neurons ◽  
Quantitative Description ◽  
Pyramidal Cells ◽  
Subcellular Localisation ◽  
Girk Channels ◽  
Ca1 Pyramidal Cells ◽  
Inwardly Rectifying

G protein-gated inwardly rectifying K+ (GIRK) channels are the main targets controlling excitability and synaptic plasticity on hippocampal neurons. Consequently, dysfunction of GIRK-mediated signalling has been implicated in the pathophysiology of Alzheimer´s disease (AD). Here, we provide a quantitative description on the expression and localisation patterns of GIRK2 in two transgenic mice models of AD (P301S and APP/PS1 mice), combining histoblots and immunoelectron microscopic approaches. The histoblot technique revealed differences in the expression of GIRK2 in the two transgenic mice models. The expression of GIRK2 was significantly reduced in the hippocampus of P301S mice in a laminar-specific manner at 10 months of age but was unaltered in APP/PS1 mice at 12 months compared to age-matched wild type mice. Ultrastructural approaches using the pre-embedding immunogold technique, demonstrated that the subcellular localisation of GIRK2 was significantly reduced along the neuronal surface of CA1 pyramidal cells, but increased in its frequency at cytoplasmic sites, in both P301S and APP/PS1 mice. We also found a decrease in plasma membrane GIRK2 channels in axon terminals contacting dendritic spines of CA1 pyramidal cells in P301S and APP/PS1 mice. These data demonstrate for the first time a redistribution of GIRK channels from the plasma membrane to intracellular sites in different compartments of CA1 pyramidal cells. Altogether, the pre- and post-synaptic reduction of GIRK2 channels suggest that GIRK-mediated alteration of the excitability in pyramidal cells could contribute to the cognitive dysfunctions as described in the two AD animal models.

scholarly journals The Density of Group I mGlu5 Receptors Is Reduced along the Neuronal Surface of Hippocampal Cells in a Mouse Model of Alzheimer’s Disease

2021 ◽  
Vol 22 (11) ◽  
pp. 5867
Author(s):  
Alejandro Martín-Belmonte ◽  
Carolina Aguado ◽  
Rocío Alfaro-Ruiz ◽  
José Luis Albasanz ◽  
Mairena Martín ◽  
...  
Keyword(s):  
Metabotropic Glutamate Receptor ◽  
Granule Cells ◽  
Quantitative Description ◽  
Pyramidal Cells ◽  
Receptor Subtype ◽  
Subcellular Localisation ◽  
Principal Cells ◽  
Metabotropic Glutamate ◽  
Model Of Alzheimer’S Disease ◽  
Group I

Metabotropic glutamate receptor subtype 5 (mGlu5) is implicated in the pathophysiology of Alzheimer´s disease (AD). However, its alteration at the subcellular level in neurons is still unexplored. Here, we provide a quantitative description on the expression and localisation patterns of mGlu5 in the APP/PS1 model of AD at 12 months of age, combining immunoblots, histoblots and high-resolution immunoelectron microscopic approaches. Immunoblots revealed that the total amount of mGlu5 protein in the hippocampus, in addition to downstream molecules, i.e., Gq/11 and PLCβ1, was similar in both APP/PS1 mice and age-matched wild type mice. Histoblots revealed that mGlu5 expression in the brain and its laminar expression in the hippocampus was also unaltered. However, the ultrastructural techniques of SDS-FRL and pre-embedding immunogold demonstrated that the subcellular localisation of mGlu5 was significantly reduced along the neuronal surface of hippocampal principal cells, including CA1 pyramidal cells and DG granule cells, in APP/PS1 mice at 12 months of age. The decrease in the surface localisation of mGlu5 was accompanied by an increase in its frequency at intracellular sites in the two neuronal populations. Together, these data demonstrate, for the first time, a loss of mGlu5 at the plasma membrane and accumulation at intracellular sites in different principal cells of the hippocampus in APP/PS1 mice, suggesting an alteration of the excitability and synaptic transmission that could contribute to the cognitive dysfunctions in this AD animal model. Further studies are required to elucidate the specificity of mGlu5-associated molecules and downstream signalling pathways in the progression of the pathology.

Prevalence and distribution of different diarrhoeagenicEscherichia colivirulotypes in major water bodies in Bangladesh

2013 ◽  
Vol 141 (12) ◽  
pp. 2516-2525 ◽  
Author(s):  
S. AKTER ◽  
M. ISLAM ◽  
K. S. AFREEN ◽  
N. AZMUDA ◽  
S. I. KHAN ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Regional Distribution ◽  
Distribution Patterns ◽  
Aquatic Systems ◽  
Water Bodies ◽  
Virulence Determinants ◽  
Waterborne Pathogen ◽  
E Coli ◽  
Enriched Cultures ◽  
Natural Water Bodies

SUMMARYEscherichia coli, a prominent waterborne pathogen, causes a variety of gastrointestinal and extraintestinal infections that depend on virulence determinants. To monitor natural aquatic systems for virulence-associated genes ofE. coli, multiplex PCR was used in a survey covering 46 major natural water bodies in Bangladesh. DNA was extracted directly from water samples as well as from pre-enriched and enriched cultures during three successive seasons and assessed forE. colivirulotype distribution. From the five virulotypes, genes from the enterotoxigenic (ETEC), enteropathogenic (EPEC), and enterohaemorrhagic (EHEC) virulotypes were detected consistently, but genes from the enteroinvasive (EIEC) and enteroaggregative (EAEC) virulotypes were traced only occasionally. ETEC was the most prevalent virulotype, followed by EPEC. However, EIEC and EAEC virulotypes could not be detected in winter or the rainy season, respectively. Specific regional distribution patterns of differentE. colivirulotypes and their temporal fluctuations were identified. These observations may assist with assessing seasonal risk and identifying vulnerable areas of the country prone toE. coli-associated outbreaks.

scholarly journals Vineyard ecosystems are structured and distinguished by fungal communities impacting the flavour and quality of wine

2019 ◽  
Author(s):  
Di Liu ◽  
Qinglin Chen ◽  
Pangzhen Zhang ◽  
Deli Chen ◽  
Kate S. Howell
Keyword(s):  
Regional Distribution ◽  
Distribution Patterns ◽  
Wine Fermentation ◽  
Fungal Communities ◽  
Soil Microbiome ◽  
Soil Conditions ◽  
Wine Aroma ◽  
Wine Production ◽  
Microbial Distribution

AbstractThe flavours of foods and beverages are formed by the agricultural environment where the plants are grown. In the case of wine, the location and environmental features of the vineyard site imprint the wine with distinctive aromas and flavours. Microbial growth and metabolism play an integral role in wine production from the vineyard to the winery, by influencing grapevine health, wine fermentation, and the flavour, aroma and quality of finished wines. The mechanism by which microbial distribution patterns drive wine metabolites is unclear and while flavour has been correlated with bacterial composition for red wines, bacterial activity provides a minor biochemical conversion in wine fermentation. Here, we collected samples across six distinct winegrowing areas in southern Australia to investigate regional distribution patterns of both fungi and bacteria and how this corresponds with wine aroma compounds. Results show that soil and must microbiota distinguish winegrowing regions and are related to wine chemical profiles. We found a strong relationship between microbial and wine metabolic profiles, and this relationship was maintained despite differing abiotic drivers (soil properties and weather/ climatic measures). Notably, fungal communities played the principal role in shaping wine aroma profiles and regional distinctiveness. We found that the soil microbiome is a potential source of grape- and must-associated fungi, and therefore the weather and soil conditions could influence the wine characteristics via shaping the soil fungal community compositions. Our study describes a comprehensive scenario of wine microbial biogeography in which microbial diversity responds to surrounding environments and ultimately sculpts wine aromatic characteristics. These findings provide perspectives for thoughtful human practices to optimise food and beverage flavour and composition through understanding of fungal activity and abundance.

scholarly journals Neuronal receptors display cytoskeleton-independent directed motion on the plasma membrane

2018 ◽  
Author(s):  
R. D. Taylor ◽  
M. Heine ◽  
N. J. Emptage ◽  
L. C. Andreae
Keyword(s):  
Plasma Membrane ◽  
Neuronal Activity ◽  
Particle Tracking ◽  
Hippocampal Neurons ◽  
Intracellular Transport ◽  
Transmembrane Proteins ◽  
Single Particle Tracking ◽  
Directed Motion ◽  
Surface Movement ◽  
Transport Vesicles

AbstractDirected transport of transmembrane proteins is generally believed to occur via intracellular transport vesicles. However, using single particle tracking in rat hippocampal neurons with a pH-sensitive quantum dot probe which specifically reports surface movement of receptors, we have identified a subpopulation of neuronal EphB2 receptors that exhibit directed motion between synapses within the plasma membrane itself. This receptor movement occurs independently of the cytoskeleton but is dependent on cholesterol and is regulated by neuronal activity.

scholarly journals Circuit Integration Initiation of New Hippocampal Neurons in the Adult Brain

Cell Reports ◽  
2020 ◽  
Vol 30 (4) ◽  
pp. 959-968.e3 ◽  
Author(s):  
Chih-Hao Yang ◽  
Adrian Di Antonio ◽  
Gregory W. Kirschen ◽  
Parul Varma ◽  
Jenny Hsieh ◽  
...  
Keyword(s):  
Hippocampal Neurons ◽  
Adult Brain ◽  
Circuit Integration

scholarly journals Paradoxical Anti-Epileptic Effects of a GluR5 Agonist of Kainate Receptors

2002 ◽  
Vol 88 (1) ◽  
pp. 523-527 ◽  
Author(s):  
Ilgam Khalilov ◽  
June Hirsch ◽  
Rosa Cossart ◽  
Yehezkel Ben-Ari
Keyword(s):  
Propionic Acid ◽  
Therapeutic Approach ◽  
Hippocampal Neurons ◽  
Selective Excitation ◽  
Kainate Receptors ◽  
Kainate Receptor ◽  
Tert Butyl ◽  
Principal Cells ◽  
Selective Agonist

Kainate generates in adult hippocampal neurons a seizure but also a massive excitation of interneurons and a dramatic increase of the inhibitory drive that impinges on principal cells. This “overinhibition” is largely mediated by GluR5-containing kainate receptors that are enriched on interneurons. Here, using the neonatal intact hippocampus in vitro and the triple chamber, we first show that this mechanism is fully operative in neonatal neurons. We then report that application to one hippocampus of ( RS)-2-amino-3-(5-tert-butyl-3-hydroxy-4-isoxazolyl)propionic acid—a relatively selective agonist of GluR5 containing kainate receptors—depresses the propagation of seizure generated in the opposite hippocampus by a convulsive agent. We conclude that the selective excitation of interneurons by GluR5-containing kainate receptor agonists opens a new therapeutic approach for the epilepsies.

scholarly journals Evolutionary trends in onshore-offshore distribution patterns of mushroom coral species (Scleractinia: Fungiidae)

2012 ◽  
Vol 81 (4) ◽  
pp. 199-221 ◽  
Author(s):  
Bert W. Hoeksema
Keyword(s):  
Related Species ◽  
Coral Species ◽  
Environmental Gradients ◽  
Distribution Patterns ◽  
Similar Distribution ◽  
Closely Related Species ◽  
Species Association ◽  
Incidence Data ◽  
Coral Fauna ◽  
Mushroom Coral

A phylogenetically based comparative analysis of onshore-offshore distribution patterns of mushroom coral species (Scleractinia: Fungiidae) was made to reconstruct an evolutionary scenario for differentiation in fungiid shelf habitats. This phyloecological study integrates data on fungiid distribution patterns along environmental gradients on the Spermonde Shelf, SW Sulawesi, with a recently published phylogeny reconstruction of the Fungiidae. A mushroom coral fauna of 34 species was used to compare their distributions by use of 50-m2 belt quadrats in transects (1) from the mainland to the shelf edge, (2) around reefs with regard to predominant wind directions, and (3) over bathymetrical reef zones. Species association ordinations were made for each of the four shelf zones using both abundance and incidence data to examine whether closely related species cooccurred. Some closely related species or even sister species appeared to show very similar distribution patterns and to coexist in high abundances. These results indicate that there may not be community saturation and competitive exclusion among mushroom corals species, most of which are free-living. In reconstructions of fungiid habitat evolution, offshore reef slopes appear to be original (ancestral), whereas onshore habitats, shallow reef flats, and deep sandy reef bases seem to be derived. The latter is in contrast with an earlier hypothesis, in which deep sandy substrates were considered ancestral mushroom coral habitats.

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