Two types of K+ currents in marginal cells cultured from rat stria vascularis

1997 ◽  
Vol 112 (1-2) ◽  
pp. 186-198 ◽  
Author(s):  
Sang Jeong Kim ◽  
Steven K. Juhn
Keyword(s):  
Stria Vascularis ◽  
Marginal Cells ◽  
K Currents ◽  
Cells Cultured

Another role for melanocytes: their importance for normal stria vascularis development in the mammalian inner ear

Development ◽  
1989 ◽  
Vol 107 (3) ◽  
pp. 453-463 ◽  
Author(s):  
K.P. Steel ◽  
C. Barkway
Keyword(s):  
Neural Crest ◽  
Basal Cell ◽  
Stria Vascularis ◽  
Normal Adult ◽  
Basal Cells ◽  
Cochlear Duct ◽  
Cell Layers ◽  
Marginal Cells ◽  
Intermediate Cells ◽  
And Function

The stria vascularis of the mammalian cochlea is composed primarily of three types of cells. Marginal cells line the lumen of the cochlear duct and are of epithelial origin. Basal cells also form a continuous layer and they may be mesodermal or derived from the neural crest. Intermediate cells are melanocyte-like cells, presumably derived from the neural crest, and are scattered between the marginal and basal cell layers. The marginal cells form extensive interdigitations with the basal and intermediate cells in the normal adult stria. The stria also contains a rich supply of blood vessels. We investigated the role of melanocytes in the stria vascularis by studying its development in a mouse mutant, viable dominant spotting, which is known to have a primary neural crest defect leading to an absence of recognisable melanocytes in the skin. Melanocytes were not found in the stria of most of the mutants examined, and from about 6 days of age onwards a reduced amount of interdigitation amongst the cells of the stria was observed. These ultrastructural anomalies were associated with strial dysfunction. In the normal adult mammal, the stria produces an endocochlear potential (EP), a resting dc potential in the endolymph in the cochlear duct, which in mice is normally about +100 mV. In our control mice, EP rose to adult levels between 6 and 16 days after birth. In most of the mutants we studied, EP was close to zero at all ages from 6 to 20 days. Melanocyte-like cells appear to be vital for normal stria vascularis development and function. They may be necessary to facilitate the normal process of interdigitation between marginal and basal cell processes at a particular stage during development, and the lack of adequate interdigitation in the mutants may be the cause of their strial dysfunction. Alternatively, melanocytes may have some direct, essential role in the production of an EP by the stria. Melanocytes may be important both for normal strial development and for the production of the EP. We believe this is the clearest demonstration yet of a role for migratory melanocytes other than their role in pigmentation.

KCNJ10 (Kir4.1) potassium channel knockout abolishes endocochlear potential

2002 ◽  
Vol 282 (2) ◽  
pp. C403-C407 ◽  
Author(s):  
Daniel C. Marcus ◽  
Tao Wu ◽  
Philine Wangemann ◽  
Paulo Kofuji
Keyword(s):  
Driving Force ◽  
Stria Vascularis ◽  
Endocochlear Potential ◽  
Sensory Transduction ◽  
Basal Cells ◽  
Transport Pathways ◽  
Main Charge ◽  
Marginal Cells ◽  
Intermediate Cells ◽  
Two Barriers

Stria vascularis of the cochlea generates the endocochlear potential and secretes K+. K+ is the main charge carrier and the endocochlear potential the main driving force for the sensory transduction that leads to hearing. Stria vascularis consists of two barriers, marginal cells that secrete potassium and basal cells that are coupled via gap junctions to intermediate cells. Mice lacking the KCNJ10 (Kir4.1) K+ channel in strial intermediate cells did not generate an endocochlear potential. Endolymph volume and K+ concentration ([K+]) were reduced. These studies establish that the KCNJ10 K+ channel provides the molecular mechanism for generation of the endocochlear potential in concert with other transport pathways that establish the [K+] difference across the channel. KCNJ10 is also a limiting pathway for K+ secretion.

Positive endocochlear potential: Mechanism of production by marginal cells of stria vascularis

1987 ◽  
Vol 29 (2-3) ◽  
pp. 117-124 ◽  
Author(s):  
Franklin F. Offner ◽  
Peter Dallos ◽  
Mary Ann Cheatham
Keyword(s):  
Stria Vascularis ◽  
Endocochlear Potential ◽  
Potential Mechanism ◽  
Marginal Cells

Horseradish Peroxidase Permeation from the Capillaries of the Stria Vascularis after Inoculation of Endotoxin into the Middle Ear

1997 ◽  
Vol 106 (5) ◽  
pp. 394-398 ◽  
Author(s):  
Kensuke Watanabe ◽  
Yasuo Tanaka
Keyword(s):  
Horseradish Peroxidase ◽  
Middle Ear ◽  
Stria Vascularis ◽  
Femoral Vein ◽  
Cell Junctions ◽  
Intercellular Spaces ◽  
Basal Turn ◽  
Pinocytotic Vesicles ◽  
Marginal Cells ◽  
Intermediate Cells

Escherichia coli-derived endotoxin was inoculated in the middle ear of guinea pigs 24 hours after being injected intraperitoneally. Twenty-four hours after the middle ear inoculation, horseradish peroxidase (HRP) was injected via the femoral vein and the permeability of HRP through the capillaries of the stria vascularis and the destination of the leaked HRP were examined. A large amount of HRP leaked out of the capillary through the opened endothelial cell junctions and penetrated the enlarged intercellular spaces. Leaked HRP entered the pinocytotic vesicles of the intermediate cells. Even slightly degenerated intermediate cells retained this function. The HRP penetrated the spongelike structure of the marginal cells leading to the intercellular space. This structure was not observed without endotoxin. The HRP could not pass to the cochlear duct through the tight junctions between marginal cells. Blood sludging was observed in the strial capillaries. It appeared more frequently in the upper three turns than in the basal turn. The HRP leakage out of the capillaries was observed not only in the upper three turns but also in the basal turn.

The Morphologic Effects of Histamine on the Lateral Cochlear Wall

1979 ◽  
Vol 87 (5) ◽  
pp. 666-684 ◽  
Author(s):  
Arndt J. Duvall ◽  
Margaret J. Hukee ◽  
Peter A. Santi
Keyword(s):  
Stria Vascularis ◽  
Spiral Ligament ◽  
Glycogen Depletion ◽  
Intercellular Spaces ◽  
Pore System ◽  
Vessel Permeability ◽  
Dependent Change ◽  
Mode Of Transport ◽  
Marginal Cells ◽  
Dose Dependent

The chinchilla lateral cochlear wall (stria vascularis, spiral ligament, and spiral prominence) was examined by morphologic and histochemical techniques following various doses of intravenous histamine. The three main findings were as follows: (1) the basic ultrastructure was not altered by histamine; (2) there is a time- and dose-dependent change in the rate of stria vascularis vessel permeability to a small protein tracer (horseradish peroxidase), but the mode of transport (large pore system) is unchanged; and (3) glycogen depletion in stria marginal cells occurs with its apparent mobilization into stria intercellular spaces.

scholarly journals Quantitative immunocytochemical localization of Na+,K+-ATPase alpha-subunit in the lateral wall of rat cochlear duct.

1989 ◽  
Vol 37 (3) ◽  
pp. 353-363 ◽  
Author(s):  
T Iwano ◽  
A Yamamoto ◽  
K Omori ◽  
M Akayama ◽  
T Kumazawa ◽  
...  
Keyword(s):  
Plasma Membranes ◽  
Rat Kidney ◽  
Stria Vascularis ◽  
Basolateral Membrane ◽  
Lateral Wall ◽  
Alpha Subunit ◽  
Membrane Domain ◽  
Cochlear Duct ◽  
Gold Particles ◽  
Marginal Cells

Ultrastructural localization of the alpha-subunit of Na+,K+-ATPase on the lateral wall of rat cochlear duct was investigated quantitatively by the protein A-gold method, using affinity-purified antibody against the alpha-subunit of rat kidney Na+,K+-ATPase. In the stria vascularis, gold particles were sparse over the endolymphatic luminal surface of the marginal cells but were numerous over the basolateral membrane. The labeling density of the basolateral membrane was almost equal to that of the same domain of the distal tubule cells of kidney. The intermediate cells were studded with a large number of gold particles on the plasma membrane domain facing the basolateral domain of the marginal cells. On the luminal surfaces of the other epithelial cells, including those of Reissner's membrane, no significant amount of gold particles was found. Many gold particles were localized on all the plasma membranes of the spiral prominence stromal cells and on the intracellular membrane domain of the external sulcus cells.

Role of glycosaminoglycans and collagen in the development of a fibronectin-rich extracellular matrix in cultured embryonic corneal epithelial cells

1984 ◽  
Vol 67 (1) ◽  
pp. 189-202
Author(s):  
D.L. Mattey ◽  
D.R. Garrod
Keyword(s):  
Extracellular Matrix ◽  
Epithelial Cells ◽  
Immunofluorescent Staining ◽  
Corneal Epithelial Cells ◽  
Corneal Epithelial ◽  
Collagen Secretion ◽  
The Matrix ◽  
Coated Surface ◽  
Marginal Cells ◽  
Cells Cultured

Corneal epithelial cells from 15-day chick embryos produce a fibronectin-rich extracellular matrix when cultured on glass, plastic and fibronectin-coated substrata. Cell culture in the presence of Streptomyces hyaluronidase or chondroitinase ABC resulted in considerable reduction of the matrix; collagenase had a lesser effect but nevertheless also reduced the matrix. In all enzyme treatments the cells attached and spread to form characteristic epithelial cell islands, but the marginal cells of these islands showed a marked reduction in the number of lamellipodia and focal contacts. Also, the immunofluorescent staining pattern for fibronectin was considerably reduced. Control cells cultured on a fibronectin-coated surface were able to reorganize the fibronectin into fibrils, whereas cells cultured in enzymes showed little or no ability to do so. The cellular reorganization of fibronectin could also be inhibited by the addition of L-azetidine-2-carboxylic acid (LACA), an inhibitor of collagen secretion. Cells plated out in the presence of LACA spread much better on collagen substrata than on plastic, glass or fibronectin. However, in all cases very little fibronectin matrix was detectable in the epithelial islands. The results suggest that components of the extracellular matrix (ECM) such as collagen, hyaluronic acid and chondroitin sulphates are not essential for the initial attachment and spreading of corneal epithelial cells in culture, but are important in the development of the ECM, and in maintaining a flattened morphology and spreading behaviour. It is suggested that fibronectin plays an important role in these interactions and that the ability of cells to organize fibronectin into fibrils is dependent on the presence of other ECM components such as glycosaminoglycans and collagen.

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