ISSN:0301-1569    

DOI:10.1159/000276711

出版商:S. Karger AG    

年代:1995

数据来源: Karger

ISSN:0301-1569    

DOI:10.1159/000276712

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

The present study is the first consecutive analysis of the adult normal human organ of Corti and vestibular hair cells with regard to the expression of F-actin, actin-associated proteins (alpha-actinin, alpha- and beta-spectrins, vinculin and tropomyosin), beta-tubulin and the calcium-binding protein synaptophysin. The expression of these cytoskeletal and their associated proteins in man is largely similar to, although not identical with, that previously described for several other mammalian species. However, a few very unusual staining patterns were found. In several long outer hair cells a rod of F-actin extended from the infracuticular area to the cell nucleus. Fluorescence for tropomyosin occurred both in the cuticular plates of the outer and inner hair cells, and in the area of close apposition between the base of the outer hair cell and the apical part of Deiter’s cell. In contrast, the vestibular hair cells showed immunoreactivity for tropomyosin only in the cuticular plate

ISSN:0301-1569    

DOI:10.1159/000276713

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

The adult normal human spiral ganglion (SG) was analyzed with regard to ultrastructure and immunohistochemistry. The cytoskeleton of the SG cells was found to comprise F-actin, intermediate filaments (IFs) and microtubules (MTs). The IF subgroups (cytokeratins, Cks; neurofilaments, NFs, vimentin, glial fibrillary acidic proteins, GFAP; desmin) displayed characteristic staining patterns. Ck No. 8 was found in all SG cells, whereas vimentin was lacking. GFAP stained only a small subpopulation of SG cells (type 2?). The light (68 kD) and medium-sized chains of NFs occurred in all SG cells and axons, whereas the 200-kD NF subunit was only found in the axonal hillock of (type 2?) SG cells, but in no other part of the cytoplasm, and regionally in nerve fibres. MAP-1 and MAP-2 occurred in all SG cells but only MAP-1 was found in the nerve fibres. The calcium-binding protein synaptophysin (SY) was expressed only in SG cells, in contrast to the S-100 which occurred more generally in the labyrinth. The neuropeptides VIP and substance P were identified in all SG cells, in contrast to NPY which was expressed in a small sub-population of SG cell (type 2?). Staining for neuron-specific enolase (NSE) identified most (type 1?) but not all SG cells. The cell surface glycoprotein Thy-1 was expressed in SG cells in a way similar to that described for neurons in the CNS. The SG cells express a high degree of cytoskeletal complexity, allowing one to distinguish between type 1 and type 2 cells. The cell bodies and their adjacent nerve fibres show characteristic features of calcium-binding proteins, surface membrane glycoproteins, NSE and neuropeptides but the basic pattern is still similar to neurons in the CNS.

ISSN:0301-1569    

DOI:10.1159/000276714

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

The distribution of microtubule-associated proteins MAP-1 and MAP-2 was analysed with immunomorphological techniques in the serially sectioned adult human membranous labyrinth. In the organ of Corti, monoclonal antibodies to MAP-1 did not stain. Positivity for MAP-2 occurred in the entire outer hair cell cytoplasm, in the inner hair cells (?), in the nerve fibres and in the cytoplasm of epithelial cells of the spiral prominence. In addition, staining for MAP-2 was identified in many (but not all) cells or Reissner’s membrane. Immunofluorescence for MAP-1 occurred in the supporting cells of the cristae and maculae interpreted to be localized in the apical region adjacent to the sensory cells. Thus, the distribution of MAP-1 and MAP-2 in the adult human membranous labyrinth was the same as described for several animal species with regard to the cochlea. In contrast to such a pattern, both MAP-1 and MAP-2 were identified in the human vestibular organs, thus identifying a subpopulation of centrally located nerve calyces and possibly also the apical portion of vestibular hair cell

ISSN:0301-1569    

DOI:10.1159/000276715

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Immunofiuorescence for hyaluronic acid occurred intracellularly in morphologically highly specialized areas in the adult human inner ear, for instance in the cuticular plates of all types of hair cells, at the apposition between outer hair cells and Deiter’s cell bodies and in the near-surface area of Hensen’s cells. The cytoskeletal organization in these regions is characterized by tightly packed filamentous proteins. Under physiological stimulus these regions undergo micromechanical change, either actively moving (force generation) or passively vibrating with changes in elasticity. Hyaluronic acid might therefore act as a friction-reducing molecular lubricant. In the lateral wall of the cochlea an accumulation of hyaluronic acid occurred in the loose connective tissue of the spiral ligament, in particular close to the stria vascularis. Due to its complex molecular network, hyaluronic acid offers considerable resistance to bulk flow of water and may exclude molecules. The basal cell region of the stria vascularis is thus given additional support to minimize (seal?) the stria vascularis towards all other areas except the endolymphatic space. Here, hyaluronic acid could act as a molecular fil

ISSN:0301-1569    

DOI:10.1159/000276716

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Serially sectioned human and squirrel monkey labyrinths were analyzed with high-resolution light microscopy after using 25 different monoclonal antibodies (mAbs) identifying all three main classes of cytoskeletal proteins. A high degree of similarity was found in labyrinths from man and squirrel monkey. Only 1 of 25 mAbs stained differently between the two species. In the squirrel monkey but not in the human the mAbs identifying S-100 proteins stained subpopulations of type I vestibular hair cells in the striola of the two macula and the summit of the cristae as compared to the same type of hair cells in the periphery of vestibular organs. Such an establishment of subpopulations of hair cells with the same ultrastructure has previously not been described in higher vertebrates. In contrast to the species differences in the distribution of neuroactive substances, the cytoskeletal architecture seems to be relatively unchanged and stable during evolution. Since each species has its own hearing and equilibrium function, neurotransmitters (neuropeptides, amino acids, etc.) could contribute to such species-specific functions.

ISSN:0301-1569    

DOI:10.1159/000276717

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

The distribution of one of the calcium-binding proteins, calbindin-D28K (CB-D28K), was studied in the adult human and squirrel monkey inner ear by means of immunocytochemical methods. Inner and outer hair cells in the organ of Corti and vestibular hair cells showed CB-D28K immunoreactivity, though some vestibular hair cells were devoid of immunoreactivity. In the spiral and vestibular ganglion, immunoreactive cells were found in both the squirrel monkey and human. The present results indicate that CB-D28K is localized within afferent neuronal components in these sensory organs and may regulate Ca++ levels for optimal neurotransmission in the primate auditory and vestibular systems. This study also provides evidence of two nonneuronal localizations of CB-D28K in the squirrel monkey. Subpopulations of fibrocytes in the spiral ligament and vestibular end organs were enriched with CB-D28K, suggesting that these cells are possibly equipped with the function to regulate Ca++ concentration in the perilymphatic fluid. In the maculae, many CB-D28K-immunoreactive particles were found in the otoconial membrane, indicating that CB-D28K may participate in the formation of otoconia.

ISSN:0301-1569    

DOI:10.1159/000276718

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

The cytoskeletal organization of the guinea pig vestibular sensory cells was investigated employing the saponin perfusion method using scanning electron microscopy as well as immunohistochemical technique. The intermediate filaments were demonstrated in the sensory cells. They were usually seen surrounding the nucleus and extending through the cytoplasm which connected the nuclear membrane to the plasma membrane, cuticular plate or other cytoorganelles. These findings may suggest that the intermediate filaments provide mechanical support to the cell and its nucleus. Microtubules were found mainly in the supranuclear portion of the cells and run parallel to the main axis of the cell body, which is directly connected to the cuticular plate. These findings may suggest that the microtubules provide mechanical support to the cell and may be closely related to the sensory cell transduction system. The actin filaments were densely packed in the site of the cuticular plate. They also distributed throughout the cytoplasm, which appeared as a dense network in the periphery region. These findings support the idea that the actin filaments could be responsible for sensory cell transduction as well as to give mechanical strength to the surface of the cell and enable the cell to change its shape and move.

ISSN:0301-1569    

DOI:10.1159/000276719

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

The effect of two substances (α-bungarotoxin, α-BGTX, a small protein, and the local anesthetic bupivacaine hydrochloride) with an assumed effect on outer hair cell (OHC) motility were analyzed after exposing the cochlea via the round window membrane. Electrophysiological measurements were performed with a very narrow frequency-specific gating ( ± 100 Hz) technique to determine auditory brainstem response (ABR) thresholds, including ABR-based frequency tuning curves. Exposure to α-BGTX gave a minor improvement in thresholds, interpreted as a facilitation of OHCs, i.e. releasing their efferent inhibitory control, whereas exposure to bupivacaine hydrochloride impaired ABR thresholds, possibly due to immobilization of OHC motility via the lateral cell membrane. Our results are consistent with the hypothesis that efferent influence on the cochlea may be linked with a modulation of the mechanical function of OHCs. We can now postulate that there is in vivo evidence that acetylcholine exerts its effect at the OHCs via an α-BGTX binding acetylcholine rece

ISSN:0301-1569    

DOI:10.1159/000276720

出版商:S. Karger AG    

年代:1995

数据来源: Karger