Relationship of the Cochlear Aqueduct and Inner Ear Pressure in M??ni??re's Disease and in a Normal Population

2001 ◽  
Vol 22 (4) ◽  
pp. 534-538 ◽  
Author(s):  
Cuneyt Yilmazer ◽  
Levent Sennaroglu ◽  
Figen Basaran ◽  
Gonca Sennaroglu
Keyword(s):  
Inner Ear ◽  
Normal Population ◽  
Cochlear Aqueduct ◽  
Relationship Of ◽  
Inner Ear Pressure

Relationship of Vestibular Aqueduct and Inner Ear Pressure in M??ni??re???s Disease and the Normal Population

2001 ◽  
Vol 111 (9) ◽  
pp. 1625-1630 ◽  
Author(s):  
Levent Sennaroglu ◽  
Cuneyt Ylmazer ◽  
Figen Basaran ◽  
Gonca Sennaroglu ◽  
Bulent Gursel
Keyword(s):  
Inner Ear ◽  
Normal Population ◽  
Vestibular Aqueduct ◽  
Relationship Of ◽  
Inner Ear Pressure

scholarly journals Intracochlear Drug Injections through the Round Window Membrane: Measures to Improve Drug Retention

2016 ◽  
Vol 21 (2) ◽  
pp. 72-79 ◽  
Author(s):  
Stefan K. Plontke ◽  
Jared J. Hartsock ◽  
Ruth M. Gill ◽  
Alec N. Salt
Keyword(s):  
Inner Ear ◽  
Round Window ◽  
Fluorescein Isothiocyanate ◽  
Oval Window ◽  
Round Window Membrane ◽  
Fluid Exchange ◽  
Cochlear Aqueduct ◽  
Quantitative Manner ◽  
Almost All ◽  
Inner Ear Pressure

The goal of this study was to develop an appropriate methodology to apply drugs quantitatively to the perilymph of the ear. Intratympanic applications of drugs to the inner ear often result in variable drug levels in the perilymph and can only be used for molecules that readily permeate the round window (RW) membrane. Direct intracochlear and intralabyrinthine application procedures for drugs, genes or cell-based therapies bypass the tight boundaries at the RW, oval window, otic capsule and the blood-labyrinth barrier. However, perforations can release inner ear pressure, allowing cerebrospinal fluid (CSF) to enter through the cochlear aqueduct, displacing the injected drug solution into the middle ear. Two markers, fluorescein or fluorescein isothiocyanate-labeled dextran, were used to quantify how much of an injected substance was retained in the cochlear perilymph following an intracochlear injection. We evaluated whether procedures to mitigate fluid leaks improved marker retention in perilymph. Almost all procedures to reduce volume efflux, including the use of gel for internal sealing and glue for external sealing of the injection site, resulted in improved retention of the marker in perilymph. Adhesive on the RW membrane effectively prevented leaks but also influenced fluid exchange between CSF and perilymph. We conclude that drugs can be delivered to the ear in a consistent, quantitative manner using intracochlear injections if care is taken to control the fluid leaks that result from cochlear perforation.

Immunology of the inner ear: Response of the inner ear to antigen challenge

1983 ◽  
Vol 91 (1) ◽  
pp. 18-23 ◽  
Author(s):  
Jeffrey P. Harris
Keyword(s):  
Inner Ear ◽  
Blood Brain Barrier ◽  
Guinea Pigs ◽  
Keyhole Limpet Hemocyanin ◽  
Host Immunity ◽  
Brain Barrier ◽  
Antigen Challenge ◽  
Antibody Titers ◽  
Relationship Of ◽  
The Relationship

The relationship of the inner ear to host immunity and the immunoresponsiveness of the inner ear to antigen challenge were investigated. A radioimmunoassay was used to quantitate antibody titers to keyhole-limpet hemocyanin generated in the serum, perilymph, and CSF of guinea pigs following systemic or inner ear immunizations. The results of these experiments demonstrate (1) the blood-labyrinth barrier is analogous to the blood-brain barrier with respect to immunoglobulin equilibrium, (2) the inner ear is capable of responding to antigen challenge, and (3) the inner ear is an effective route for systemic immunization.

Volume receptors in guinea pig labyrinth: relevance with respect to ADH and Na control

1989 ◽  
Vol 257 (3) ◽  
pp. F341-F346 ◽  
Author(s):  
E. Bartoli ◽  
A. Satta ◽  
F. Melis ◽  
M. A. Caria ◽  
W. Masala ◽  
...  
Keyword(s):  
Inner Ear ◽  
Guinea Pigs ◽  
Control Mechanism ◽  
Extracellular Fluid ◽  
Urine Osmolality ◽  
Neural Pathways ◽  
Group Of Seven ◽  
Before And After ◽  
Pressure Changes ◽  
Inner Ear Pressure

We tested the hypothesis that changes in extracellular fluid volume are reflected by pressure changes within structures of the inner ear and that through neural pathways, a control mechanism exerts an influence on antidiuretic hormone (ADH) release and Na excretion. The study was performed on 35 guinea pigs. In protocol 1, 13 animals were studied before and after decompression of the inner ear by bilateral fluid withdrawal in an experimental setting of sustained isotonic expansion that kept the osmoreceptor partially activated and the intrathoracic volume receptors suppressed. A group of six sham-operated animals served as control. In protocol 2, nine animals were studied before and after a unilateral rise in their inner ear pressure during slightly hypertonic low-rate infusions that kept the osmoreceptor and thoracic volume receptors stimulated. A group of seven sham-operated guinea pigs served as controls. Decompression of the inner ear was attended by a rise in plasma ADH from 11.9 +/- 2.4 to 29.1 +/- 6.9 pg/ml, in urine osmolality (Uosmol) from 470 +/- 48 to 712 +/- 46 mosmol/kg (P less than 0.001), and a fall in urine flow rate (V) from 184 +/- 47 to 71 +/- 11 microliters/min (P less than 0.01), whereas plasma Na (PNa) and osmolality (Posmol) did not change. During inner ear hypertension, plasma ADH fell from 25.6 +/- 3.9 to 18.4 +/- 3.1, Uosmol from 829 +/- 58 to 627 +/- 43 (P less than 0.001), and V rose from 51 +/- 11 to 130 +/- 23 (P less than 0.001), whereas glomerular filtration rate, PNa, and Posmol did not change.(ABSTRACT TRUNCATED AT 250 WORDS)

Functional Patency of the Cochlear Aqueduct

1982 ◽  
Vol 91 (2) ◽  
pp. 209-215 ◽  
Author(s):  
Björn Carlborg ◽  
Barbara Densert ◽  
Ove Densert
Keyword(s):  
Cerebrospinal Fluid ◽  
Inner Ear ◽  
Middle Ear ◽  
Ambient Pressure ◽  
Ear Canal ◽  
Cochlear Aqueduct ◽  
Pressure Release ◽  
Release Capacity ◽  
Before And After ◽  
Pressure Changes

The perilymphatic (P P) and cerebrospinal fluid (P CSF) pressures were investigated in relation to pressure variations in the ear canal, middle ear and intracranial compartment before and after occlusion of the cochlear aqueduct (CA). Experiments using intracranial infusion showed that the CA was responsible for a perfect hydrodynamic balance between the CSF and the perilymph. There are indications of additional pressure release factors but their capacities were not sufficient to prevent the appearance of a longstanding and substantial pressure gradient following occlusion of the CA. A gradual P P build-up, from zero to its original level after the CA was opened and occluded, indicated perilymph production within the labyrinth. Investigation of pressure transfer from the ear canal and middle ear to the perilymph showed that the CA was the major pressure release route from the cochlea. Occlusion of the CA reduced the compliance of the inner ear and severely reduced the pressure release capacity. In such a situation the inner ear is almost incapable of equilibrating ambient pressure changes.

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