Intercellular Fluid Pathways in the Organ of Corti of Cat and Man

1979 ◽  
Vol 88 (1) ◽  
pp. 2-11 ◽  
Author(s):  
Joseph B. Nadol
Keyword(s):  
Stria Vascularis ◽  
Organ Of Corti ◽  
Intercellular Junctions ◽  
Morphological Evidence ◽  
Spiral Ligament ◽  
Basal Cells ◽  
Scala Tympani ◽  
Supporting Cells ◽  
Cochlear Duct ◽  
Scala Vestibuli

The intercellular junctions in the organ of Corti of cat and man were examined with the electron microscope. In contrast to the zone of tight junctions, or zonulae occludentes, which were present at the surface of cells lining the scala media, there was no tight junctional specialization among the cells of the tympanic lamina, perilymphatic lining cells of the scala vestibuli, basal processes of the supporting cells of the organ of Corti or cells of the spiral limbus and spiral ligament. These findings suggest the possibility of fluid continuity between the scala vestibuli and scala tympani all along the cochlear duct. Morphological evidence for an intercellular diffusion barrier was present only at the endolymphatic surfaces of the cochlear duct and between the processes of the basal cells of the stria vascularis in cat and man.

Comparative Measurements of Cochlear Apparatus

1968 ◽  
Vol 11 (2) ◽  
pp. 229-235 ◽  
Author(s):  
Makoto Igarashi ◽  
Robert G. Mahon ◽  
Shizuo Konishi
Keyword(s):  
Cross Section ◽  
Basilar Membrane ◽  
Stria Vascularis ◽  
The Other ◽  
Tectorial Membrane ◽  
Spiral Ligament ◽  
Scala Tympani ◽  
Basal Turn ◽  
Temporal Bones ◽  
Scala Vestibuli

Micromeasurements of horizontal midmodiolar sections of temporal bones were performed to obtain the dimensions of the different cochlear partitions in the squirrel monkey, the cat, and the rat. The width of the basilar membrane and the tectorial membrane were larger in the apical turn than in the basal turn in all three species. The thickness of the spiral ligament, the width of Reissner’s membrane, and the width of the stria vascularis were larger in the basal turn than in the apical turn. The cross-section areas of scala vestibuli and scala tympani in the three species were larger in the basal turn than in the other turns.

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.

Ultrastructural Characteristics of Capillaries Entering and Leaving the Stria Vascularis

1986 ◽  
Vol 95 (3) ◽  
pp. 309-312 ◽  
Author(s):  
Kensuke Watanabe
Keyword(s):  
Horseradish Peroxidase ◽  
Basal Cell ◽  
Stria Vascularis ◽  
The Other ◽  
Spiral Ligament ◽  
Perivascular Spaces ◽  
Basal Cells ◽  
Vascular Flow ◽  
Cell Layers ◽  
Ultrastructural Characteristics

Capillaries entering and leaving the stria vascularis were surrounded by layers of basal cells and fibrocytes. The entering capillaries were surrounded by one or two thin basal cells, while the leaving capillaries were surrounded by four or five thicker and interdigitated basal cell layers. Moreover, the layers surrounding the leaving capillaries persisted further into the spiral ligament. Two kinds of filaments were observed in the basal cells, one thin and the other thick. Capillaries were observed to leak horseradish peroxidase before they entered and after they left the stria vascularis. Although the reaction product of horseradish peroxidase was observed in all perivascular spaces of leaving capillaries, very little or no reaction product was observed around some entering capillaries. It is speculated that the layers of basal cells and fibrocytes around entering and leaving capillaries control the vascular flow out of the stria vascularis, although the layers around leaving capillaries may be more contractile than those around entering capillaries.

scholarly journals Expression of Gap Junction Protein Connexin43 in the Adult Rat Cochlea: Comparison with Connexin26

2003 ◽  
Vol 51 (7) ◽  
pp. 903-912 ◽  
Author(s):  
Toshihiro Suzuki ◽  
Tetsuro Takamatsu ◽  
Masahito Oyamada
Keyword(s):  
Gap Junction ◽  
Stria Vascularis ◽  
Three Dimensional ◽  
Organ Of Corti ◽  
Structural Difference ◽  
Lateral Wall ◽  
Spiral Ligament ◽  
Adult Rat ◽  
Junction Protein ◽  
Rat Cochlea

To elucidate whether the two different gap junction proteins connexin43 (Cx43) and connexin26 (Cx26) are expressed and localized in a similar manner in the adult rat cochlea, we performed three-dimensional confocal microscopy using cryosections and surface preparations. In the cochlear lateral wall, Cx43-positive spots were localized mainly in the stria vascularis and only a few spots were present in the spiral ligament, whereas Cx26-positive spots were detected in both the stria vascularis and the spiral ligament. In the spiral limbus, Cx43 was widely distributed, whereas Cx26 was more concentrated on the side facing the scala vestibuli and in the basal portion. In the organ of Corti, Cx43-positive spots were present between the supporting cells but they were fewer and much smaller than those of Cx26. These data demonstrated distinct differences between Cx43 and Cx26 in expression and localization in the cochlea. In addition, the area of overlap of zonula occludens-1 (ZO-1) immunolabeling with Cx43-positive spots was small, whereas it was fairly large with Cx26-positive spots in the cochlear lateral wall, suggesting that the differences are not associated with the structural difference between carboxyl terminals, i.e., those of Cx43 possess sequences for binding to ZO-1, whereas those of Cx26 lack these binding sequences.

scholarly journals Otic Pathology of Caprine β-Mannosidosis

1988 ◽  
Vol 25 (6) ◽  
pp. 437-442 ◽  
Author(s):  
J. A. Render ◽  
K. L. Lovell ◽  
M. Z. Jones
Keyword(s):  
Storage Disease ◽  
Stria Vascularis ◽  
Genetic Disorder ◽  
Spiral Ganglion ◽  
Clinical Signs ◽  
Organ Of Corti ◽  
Scala Tympani ◽  
Electron Microscopic ◽  
Middle Ear Mucosa ◽  
Cochlear Hair Cells

Caprine β-mannosidosis is an autosomal recessive defect of glycoprotein catabolism with a deficiency of tissue and plasma β-mannosidase activity and tissue accumulation of oligosaccharides within lysosomes. This rapidly fatal genetic disorder of Nubian goats is expressed at birth by a variety of clinical signs including deafness. Affected goats had folded pinnas, and the tympanic cavity was decreased due to multiple, polypoid projections of bone covered by middle ear mucosa which obstructed the view of the cochlear promontory. Numerous cells of the cochlear duct including mesothelial and epithelial cells of Reissner's membrane, mesothelial cells lining the scala tympani, cells of the stria vascularis, numerous supportive cells of the organ of Corti, cochlear hair cells, endothelial cells, perithelial cells, fibroblasts, macrophages, and neurons of the spiral ganglion contained numerous nonstaining intracytoplasmic vacuoles which resulted in distention of affected cells and caused thickening of involved structures. Ultrastructurally, the vacuoles were membrane-bound and consistent with lysosomes. Vacuolated cells were desquamated into the scala vestibuli and scala tympani. This is one of few reports describing light and electron microscopic otic alterations of a storage disease. Goats with β-mannosidosis appear to be good models of hearing loss in patients with storage disease.

Fine Structure Histopathology of Labyrinthitis Ossificans in the Gerbil Model

2005 ◽  
Vol 114 (2) ◽  
pp. 161-166 ◽  
Author(s):  
Steven P. Tinling ◽  
Vishad Nabili ◽  
Hilary A. Brodie
Keyword(s):  
Connective Tissue ◽  
Ganglion Cells ◽  
Stria Vascularis ◽  
Spiral Ganglion ◽  
Organ Of Corti ◽  
Spiral Ligament ◽  
Otic Capsule ◽  
Dense Connective Tissue ◽  
Labyrinthitis Ossificans ◽  
End Stage

Labyrinthitis ossificans (LO) is the pathological deposition of new bone within the lumen of the cochlea and labyrinth. This process occurs most commonly as a result of infection or inflammation affecting the otic capsule. Trauma and vascular compromise can also lead to neo-ossification within the otic capsule. The mechanism that regulates this process remains unestablished. This study details the end-stage histopathology in high-resolution plastic thin sections. Twenty Mongolian gerbils were infected by intrathecal injection of Streptococcus pneumoniae type 3 followed by subcutaneous penicillin G procaine (8 days) and were painlessly sacrificed 3 months later. The cochleas were serially divided and sectioned for light and electron microscopy. Sixteen of 20 animals (27 of 40 cochleas) demonstrated LO. Cochlear damage was most extensive in the vestibule and basal turn and decreased toward the apex, which often appeared normal. The histopathologic findings consisted of 1) new bone, calcospherites, osteoid, and fibrosis without dense connective tissue or osteoblasts extending from the endosteal wall into the lumen of the vestibule and scala tympani; 2) areas of dense connective tissue and osteoid enclosed by epithelial cells conjoined with the organ of Corti, stria vascularis, spiral ligament, and vestibular (Reissner's) membrane; and 3) partial to complete loss of the organ of Corti, spiral ligament cell bodies, stria vascularis, and spiral ganglion cells. Osteoblastic activity was not demonstrated in end-stage ossification in LO in the gerbil model. Neoossification appears to occur by calcospherite deposition along collagen-like fibrils within osteoid. The destruction of the organ of Corti, spiral ganglion cells, stria vascularis, and cells of Reissner's membrane and the spiral ligament occurs even in the absence of ossification of the cochlear duct.

Distribution and significance of endothelin 1 in guinea pig cochlear lateral wall

2007 ◽  
Vol 121 (8) ◽  
pp. 721-724 ◽  
Author(s):  
D-Y Xu ◽  
Y-D Tang ◽  
S-X Liu ◽  
J Liu
Keyword(s):  
Guinea Pig ◽  
Stria Vascularis ◽  
Lateral Wall ◽  
Complex Method ◽  
Spiral Ligament ◽  
Basal Cells ◽  
Endothelin 1 ◽  
Marginal Cells ◽  
Spiral Ligament Fibrocytes ◽  
Avidin Biotin Complex

AbstractEndothelin 1 is a vasoconstrictive peptide with many biological functions. To investigate the distribution of endothelin 1 in guinea pig cochlear lateral wall and the significance of endothelin 1 in maintaining cochlear homeostasis, the immunohistochemistry avidin biotin complex method was applied by using rabbit anti-endothelin 1 polyclonal antibody as primary antibody. Endothelin-1-like activities were detected in the marginal cells, spiral prominence epithelial cells, outer sulcus cells, stria vascularis capillaries, basal cells and spiral ligament fibrocytes.These results suggest that endothelin 1 may play an important role in maintaining cochlear homeostasis.

Intercellular Junctions in the Organ of Corti

1978 ◽  
Vol 87 (1) ◽  
pp. 70-80 ◽  
Author(s):  
Joseph B. Nadol
Keyword(s):  
Tight Junctions ◽  
Intercellular Space ◽  
Basilar Membrane ◽  
Membrane Surface ◽  
Morphological Characteristics ◽  
Organ Of Corti ◽  
Intercellular Junctions ◽  
Junctional Complex ◽  
Supporting Cells ◽  
Zonula Occludens

The intercellular junctions between adjacent supporting cells and between apposed hair and supporting cells in the organ of Corti of cat and human were studied. At the endolymphatic surface, the intercellular space was closed by a series of tight junctions (zonula occludens), whereas there were no tight junctions at the basilar membrane surface of the neuro-epithelium. Beneath the adlumenal zonula occludens between adjacent supporting cells, a zonula adherens (intermediate junction, “desmosome”) was found. Many gap junctions joined apposed supporting cells both within and below the endolymphatic junctional complex. Below the zonula occludens between apposed hair and supporting cells, membrane specialization sharing the morphological characteristics of both the macula adherens and zonula adherens was found. Between areas of tight junctional specialization in the junctional complex between hair and supporting cells, there were short areas of parallel limiting membranes separated by a 20A intercellular space. These areas were suggestive but not characteristic of gap junctional specialization. The functional significance of the junctional specialization between cells in the organ of Corti was discussed.

Chronic Intracochlear Electrode Implantation: Cochlear Pathology and Acoustic Nerve Survival

1974 ◽  
Vol 83 (2) ◽  
pp. 202-215 ◽  
Author(s):  
Robert A. Schindler ◽  
Michael M. Merzenich
Keyword(s):  
Hair Cells ◽  
Bone Growth ◽  
Ganglion Cells ◽  
Stria Vascularis ◽  
Round Window ◽  
Spiral Ganglion ◽  
Nerve Fibers ◽  
Spiral Ligament ◽  
Scala Tympani ◽  
Temporal Bones

The temporal bones of ten cats implanted with intracochlear electrodes for three to 117 weeks were stained with hematoxylin and eosin and examined with light microscopy. The electrodes were embedded in Silastic® which was molded to fill the most basal 9 mm of the scala tympani. They were inserted directly into the scala through the round window. Among our observations were the following: 1) All or nearly all hair cells were lost in the basal coil during the first several weeks after implantation. Some, but not all, supporting cells were also lost. There was extensive hair cell loss in the middle and apical turns, although some hair cells were seen there in all examined cats. 2) There was evidence of degeneration of spiral ganglion cells in the basal cochlea in several animals, but most primary auditory neurons including (with two exceptions) most of those in the region directly over the electrode, survived implantation in every cat. The radial nerve fibers of the spiral ganglion cells also survived long-term implantation. The functional viability of remaining spiral ganglion cells was confirmed in acute neurophysiological experiments conducted just before the animals were sacrificed. 3) More severe degeneration was seen in two cats in which the electrode perforated the basilar partition. In these animals, there was loss of many spiral ganglion cells, and evidence of new bone growth in the region of the perforation. 4) The appearance of the stria vascularis and spiral ligament in some implanted animals paralleled their descriptions following occlusion of the cochlear vein. 5) Connective tissue formed around the electrode surfaces, apparently displacing perilymph and sealing the electrode into the scala tympani. There was no evidence of perilymph fistula in any animal. 6) There was little evidence of progressive degeneration of the organ of Corti or spiral ganglion from three to 34 weeks after implantation. Some of the implications and limitations of these findings are discussed.

Connexin 26 Immunohistochemistry in Temporal Bones With Cochlear Otosclerosis

2018 ◽  
Vol 127 (8) ◽  
pp. 536-542 ◽  
Author(s):  
Mia E. Miller ◽  
Ivan A. Lopez ◽  
Fred H. Linthicum ◽  
Akira Ishiyama
Keyword(s):  
Hearing Loss ◽  
Stria Vascularis ◽  
Organ Of Corti ◽  
Connexin 26 ◽  
Spiral Ligament ◽  
Mixed Hearing Loss ◽  
Cell Counts ◽  
Normal Hair ◽  
Connexin 30 ◽  
Temporal Bones

Hypothesis: Connexin-26 (Cx26) expression is diminished in the spiral ligament of subjects with hearing loss and cochlear otosclerosis (CO). Background: Human temporal bone (HTB) studies have demonstrated that CO is associated with hyalinization of the spiral ligament. We hypothesize that hyalinization is associated with a loss of fibrocytes with a consequent decline in Cx26 expression. Cx26 and Connexin-30 (Cx30) encode gap junction proteins expressed in supporting cells of the organ of Corti, the spiral limbus, stria vascularis, and in fibrocytes of the spiral ligament. These gap junctions are critical for potassium recycling and maintenance of the endocochlear potential. Diminished expression of these proteins would likely be associated with hearing dysfunction. Methods: Histopathology and clinical characteristics of 45 HTB specimens with CO and spiral ligament hyalinization were reviewed. Those with sensorineural or mixed hearing loss but normal or near-normal hair cell counts were analyzed with light microscopy, and Cx26-immunoreactive (IR) signal was qualitatively assessed. Results: H&E staining demonstrated hyalinization in the spiral ligament and loss of type II and type III fibrocytes. Cx26-IR was diminished throughout the cochlea affected with CO compared with normal controls. Conclusions: Cx26-IR reduction in the spiral ligament of subjects with CO likely plays a role in hearing loss.

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