The influence of different fixatives and osmolality on the ultrastructure of the cochlear neuroepithelium

Anniko, Matti; Lundquist, Per‐G.

doi:10.1007/bf00469735

Cited by 25 publications

(10 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The fixative has been shown to cause minimal shrinkage and distortion of the membranes of cells of the inner ear 17 . However, to verify that the major features we report here (rostral curvature and tenuous caudal suspension of the utricular maculae) were not due to shrinkage and/or other artifacts in histological processing, we confirmed these features in guinea pigs by direct visual observation with a high‐power operating microscope of the unfixed maculae in living anesthetized animals.…”

Section: Discussionsupporting

confidence: 76%

The Configuration and Attachment of the Utricular and Saccular Maculae to the Temporal Bone

Curthoys

Uzun-Coruhlu

Wong

et al. 2009

Annals of the New York Academy of Sciences

View full text Add to dashboard Cite

High-resolution X-ray microtomography (micro-CT) was used to show the spatial configuration of the membranous labyrinth of the fixed guinea pig and human inner ear. Whole temporal bones were en bloc stained in 2% osmium tetroxide for 2 days or more to allow the osmium to attach to the membranes of the inner ear, and then scanned with a Skyscan 1172 micro-CT with highest resolution of 8 microns. The scans were segmented and reconstructed. The findings for guinea pigs and humans are similar. The saccular macula is closely attached to the curved medial wall of the temporal bone, but in both human and guinea pig the utricular macula is attached to the temporal bone only at the anterior region of the macula, and, as others have reported previously, much of the caudal area of the utricular macula is tenuously supported by a thin membrane, just above the dorsal margin of the stapes. This tenuous support may have important consequences for the sensing of forces by the utricular macula. Combining information from a dissected human horizontal canal with CT images allows an estimate of the orientation of the horizontal canal crista in human subjects, data which are necessary for treatment of benign paroyxsmal positional vertigo of the horizontal canal. The very high resolution achieved by micro-CT shows that reconstruction from inadequately sampled CT data produces images that are not anatomically correct, so that canal deformations and aplasias may appear to be present.

show abstract

Section: Discussionsupporting

confidence: 76%

The Configuration and Attachment of the Utricular and Saccular Maculae to the Temporal Bone

Curthoys

Uzun-Coruhlu

Wong

et al. 2009

Annals of the New York Academy of Sciences

View full text Add to dashboard Cite

show abstract

“…First, the fixative used (phosphate‐buffered Karnovsky's) was specifically chosen because electronmicroscopic evidence has shown that the particular concentration used here caused minimal shrinkage of labyrinth membranes at the electronmicroscopic level. 9 Second, inspection of the maculae in living anesthetized animals confirms the orientation and curvature shown by the quantitative measures. In some anesthetized guinea pigs the inner ear was opened and the utricular and saccular macula were each visualized directly through the endolymph, and they showed similar patterns of curvature to the data presented here.…”

Section: Discussionmentioning

confidence: 55%

“…Guinea pigs were deeply anesthetized with nembutal and perfused with 400 mL of saline containing heparin followed by 500 mL of phosphate‐buffered Karnovsky's fixative (4% paraformaldehyde and 5% glutaraldehyde). 9 The head was mounted in a guinea pig stereotaxic apparatus (Kopf) and the inner ear of one labyrinth was dissected to show the maculae. The otoconia and otoconial membrane were very gently removed by a fine jet of saline.…”

Section: Methodsmentioning

confidence: 99%

The Planes of the Utricular and Saccular Maculae of the Guinea Pig

Curthoys

Betts

Burgess

et al. 1999

Annals of the New York Academy of Sciences

View full text Add to dashboard Cite

To establish a link between otolith anatomy and function it is necessary to know the regions of the utricular and saccular maculae, which are stimulated by any arbitrary linear acceleration stimulus. That requires accurate information about the location and orientation of the spatially extended maculae in head-fixed coordinates and referred to head-fixed landmarks (such as Reid's line). New data showing the location of the otolithic maculae in the guinea pig with respect to head-fixed stereotaxic coordinates are presented. Guinea pigs were perfused with Karnovsky's fixative and the maculae were exposed while the head was held in a guinea pig stereotaxic device. An electrolytically sharpened fine wire held in a calibrated micromanipulator was touched to points all over the surface of each macula under visual observation with the aid of a high-power operating microscope. The x, y, z coordinates of these points were plotted using a three-dimensional plotting program. Both maculae have pronounced curvature so that dorsoventral shear forces will stimulate regions of both the utricular and saccular maculae.

show abstract

“…The mor-to determine which could best preserve this tissue. Anniko and Lundquist (1977) and Park (1984) tested glutaraldehyde fixatives for mammalian and bird inner ears and concluded that the glutaraldehyde and the Karnovsky's fixative, i.e., a mixture of paraformaldehyde and glutaraldehyde, were satisfactory. They obtained a better result with a hyperosmolar fixative solution (> 1,500 mOsm) than with a hypoosmolar one.…”

Section: Discussionmentioning

confidence: 99%

Ultrastructural study of the semicircular canal cells of the frog Rana esculenta

1988

View full text Add to dashboard Cite

The ultrastructure of the nonsensory cells (dark cells, transitional cells, and undifferentiated cells) of the frog semicircular canal was studied by using transmission electron microscopy in an attempt to correlate the structure with the functions of these epithelial cells. All the nonsensory cells were linked by tight junctions and desmosomes; this suggested that there is little paracellular ionic transport from perilymph to endolymph. In the dark cell epithelium, the apical intercellular spaces were dilated; in the basal part, numerous basolateral plasma membrane infoldings, containing mitochondria, delimited electron-lucent spaces. The undifferentiated cells and the transitional cells were devoid of any basal membrane infolding. Surrounding the semicircular canal, very flattened and interdigitated mesothelial cells constituted a thin multilayer tissue which limited the perilymphatic space. The morphological aspect of the dark cells suggests that they may play a role in the secretion and/or in the reabsorption of endolymph, which bathes the apical pole of these cells. The undifferentiated and transitional cells can play a role in the maintenance of the endolymphatic ionic composition because of their apical tight junctions and desmosomes.

show abstract

The influence of different fixatives and osmolality on the ultrastructure of the cochlear neuroepithelium

Cited by 25 publications

References 10 publications

The Configuration and Attachment of the Utricular and Saccular Maculae to the Temporal Bone

The Configuration and Attachment of the Utricular and Saccular Maculae to the Temporal Bone

The Planes of the Utricular and Saccular Maculae of the Guinea Pig

Ultrastructural study of the semicircular canal cells of the frog Rana esculenta

Contact Info

Product

Resources

About