Ossicular Vibration Changes Associated with Pressure Changes in Inner Ear and Cerebrospinal Fluid in Guinea Pigs.

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)

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Functional Patency of the Cochlear Aqueduct

Annals of Otology Rhinology & Laryngology ◽

10.1177/000348948209100219 ◽

1982 ◽

Vol 91 (2) ◽

pp. 209-215 ◽

Cited By ~ 48

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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Transmission of cerebrospinal fluid pressure changes to the inner ear and its effect on cochlear microphonics

European Archives of Oto-Rhino-Laryngology ◽

10.1007/bf00178923 ◽

1991 ◽

Vol 248 (3) ◽

Cited By ~ 20

Author(s):

M. Yoshida ◽

T. Uemura

Keyword(s):

Cerebrospinal Fluid ◽

Inner Ear ◽

Fluid Pressure ◽

Cerebrospinal Fluid Pressure ◽

Cochlear Microphonics ◽

Pressure Changes

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Inner ear pressure changes in normal guinea pigs induced by the Meniett 20

Clinical Otolaryngology ◽

10.1046/j.1365-2273.2001.00479-18.x ◽

2001 ◽

Vol 26 (4) ◽

pp. 345-345

Author(s):

R.A. Feijen ◽

J.M. Segenhout ◽

H.P. Wit ◽

F.W.J. Albers

Keyword(s):

Inner Ear ◽

Guinea Pigs ◽

Pressure Changes ◽

Inner Ear Pressure

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Monitoring Inner Ear Pressure Changes in Normal Guinea Pigs Induced by the Meniett®20

Acta Oto-Laryngologica ◽

10.1080/000164800750061633 ◽

2000 ◽

Vol 120 (7) ◽

pp. 804-809 ◽

Cited By ~ 8

Author(s):

R. A. Feijen ◽

J. M. Segenhout ◽

H. P. Wit ◽

F. W. J. Albers

Keyword(s):

Inner Ear ◽

Guinea Pigs ◽

Pressure Changes ◽

Inner Ear Pressure

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Pressure Gradients Affecting the Labyrinth during Hypobaric Pressure

Annals of Otology Rhinology & Laryngology ◽

10.1177/000348949710600610 ◽

1997 ◽

Vol 106 (6) ◽

pp. 495-502 ◽

Cited By ~ 10

Author(s):

Konrád S. Konrádsson ◽

Björn I. R. Carlborg ◽

Joseph C. Farmer

Keyword(s):

Cerebrospinal Fluid ◽

Eustachian Tube ◽

Ambient Pressure ◽

Pressure Gradients ◽

Cochlear Aqueduct ◽

Fluid Compartment ◽

Large Pressure ◽

Fluid Compartments ◽

Pressure Changes ◽

Considerable Pressure

Hypobaric effects on the perilymph pressure were investigated in 18 cats. The perilymph, tympanic cavity, cerebrospinal fluid, and systemic and ambient pressure changes were continuously recorded relative to the atmospheric pressure. The pressure equilibration of the eustachian tube and the cochlear aqueduct was studied, as well as the effects of blocking these channels. During ascent, the physiologic opening of the eustachian tube reduced the pressure gradients across the tympanic membrane. The patent cochlear aqueduct equilibrated perilymph pressure to cerebrospinal fluid compartment levels with a considerable pressure gradient across the oval and round windows. With the aqueduct blocked, the pressure decrease within the labyrinth and tympanic cavities was limited, resulting in large pressure gradients toward the chamber and the cerebrospinal fluid compartments, respectively. We conclude that closed cavities with limited pressure release capacities are the cause of the pressure gradients. The strain exerted by these pressure gradients is potentially harmful to the ear.

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Oligoclonal IgG in the cerebrospinal fluid of guinea pigs with acute experimental allergic encephalomyelitis

Journal of the Neurological Sciences ◽

10.1016/0022-510x(82)90241-6 ◽

1982 ◽

Vol 53 (3) ◽

pp. 433-441 ◽

Cited By ~ 5

Author(s):

Abdolmohammad Rostami ◽

Robert P. Lisak ◽

Nadine Blanchard ◽

Felicula Guerrero ◽

Burton Zweiman ◽

...

Keyword(s):

Cerebrospinal Fluid ◽

Experimental Allergic Encephalomyelitis ◽

Guinea Pigs ◽

Allergic Encephalomyelitis ◽

Oligoclonal Igg ◽

Experimental Allergic

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

Otolaryngology ◽

10.1177/019459988309100105 ◽

1983 ◽

Vol 91 (1) ◽

pp. 18-23 ◽

Cited By ~ 106

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.

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