The measurement and manipulation of intralabyrinthine pressure in experimental endolymphatic hydrops

Andrews, James C.; Böhmer, Andreas; Hoffman, Larry F.

doi:10.1288/00005537-199106000-00015

Cited by 54 publications

(30 citation statements)

References 57 publications

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“…The ES has been hypothesized to regulate endolymphatic hydrostatic pressure (4,9). However, no reports have described hydrostatic pressure regulation by the ES, as direct measurement of endolymphatic hydrostatic pressure in the ES is very difficult due to the proximity of the sigmoid sinus and dura mater (24).…”

Section: The Endolymphatic Sac (Es)mentioning

confidence: 99%

“…With the aid of an operating microscope and micromanipulator, the tip of a micropipette was inserted through the round window membrane into the scala tympani, then through the basilar membrane into the scala media, in which the hydrostatic pressure of cochlear endolymph was measured. EP was simultaneously measured to verify the position of the pipette tip (4,5,27). To measure the hydrostatic pressure of cochlear perilymph, the tip of a micropipette was inserted through the round window membrane into the scala tympani (28).…”

Section: Animal Preparation and Recording Techniquementioning

confidence: 99%

“…The system was calibrated by lowering the micropipette 0 and 1 cm into an electrically grounded beaker of normal saline (4).…”

Section: Animal Preparation and Recording Techniquementioning

confidence: 99%

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Endolymphatic sac is involved in the regulation of hydrostatic pressure of cochlear endolymph

Inamoto

Miyashita

Akiyama

et al. 2009

American Journal of Physiology-Regulatory, Integrative and Comp

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To clarify the role of the endolymphatic sac (ES) in the regulation of endolymphatic pressure, the effects of isoproterenol, a ␤-adrenergic receptor agonist, and acetazolamide, a potent carbonic anhydrase inhibitor, both of which decrease ES direct current potential on cochlear hydrostatic pressure, were examined in guinea pigs. When isoproterenol was applied intravenously, hydrostatic pressures of cochlear endolymph and perilymph were significantly increased with no change in endocochlear potential or the hydrostatic pressure of cerebrospinal fluid. Acetazolamide produced no marked change in the hydrostatic pressure of cochlear endolymph. In ears with an obstructed ES, the action of isoproterenol on the hydrostatic pressure of cochlear endolymph and perilymph was suppressed. These results suggest that the ES may regulate the hydrostatic pressure of the endolymphatic system via the action of the agents such as catecholamines on the ES. direct current potential; isoproterenol; acetazolamide THE ENDOLYMPHATIC SAC (ES), which is a part of the inner ear, is believed to absorb endolymph, since surgical blockage of the ES and the endolymphatic duct causes accumulation of endolymph in the cochlea and vestibule, as so-called endolymphatic hydrops (11), a characteristic pathological finding in Meniere's disease. Endolymphatic hydrops in the cochlea causes deafness, while endolymphatic hydrops in the vestibule causes vertigo (22, 31). Endolymph regulation is thus important for hearing and the sense of equilibrium (7,29). Although the ES is generally accepted to contain active ion transport systems and may absorb endolymph (11), no mechanisms of endolymph regulation by the ES have actually been established.ES direct current potential (ESP) and endocochlear direct current potential (EP) are known to be present in the ES and the cochlea, respectively (3, 12, 15). ESP and EP are generated by active ion transports in the ES and cochlea, respectively (3, 15, 21). ESP and EP can thus be used as indices of function for the ES and cochlea, respectively (15, 21). Catecholamines reportedly depress ESP through ␤-adrenergic receptors (19). The finding that isoproterenol, a ␤-adrenergic receptor agonist, at a dose of 12.5 g/kg decreases ESP without changing EP (16), suggests that isoproterenol would suppress active ion transport in the ES without inhibiting active ion transport in the cochlea. Acetazolamide, a potent carbonic anhydrase inhibitor, reportedly depresses ESP more sensitively than EP (32, 33). The result that cotreatment with isoproterenol and acetazolamide at doses producing near-maximum reduction of ESP depresses almost all parts of the ESP, suggesting that isoproterenol and acetazolamide may depress ESP via different mechanisms and that ESP may be composed of isoproterenol-and acetazolamide-sensitive parts (17).The ES has been hypothesized to regulate endolymphatic hydrostatic pressure (4, 9). However, no reports have described hydrostatic pressure regulation by the ES, as direct measurement of endolymphatic hydrostatic ...

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Section: The Endolymphatic Sac (Es)mentioning

confidence: 99%

Section: Animal Preparation and Recording Techniquementioning

confidence: 99%

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Endolymphatic sac is involved in the regulation of hydrostatic pressure of cochlear endolymph

Inamoto

Miyashita

Akiyama

et al. 2009

American Journal of Physiology-Regulatory, Integrative and Comp

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“…Experimental models studying the efect of postural changes on endo-and perilymphatic space luid pressures show a marked change in the hydropic versus control animals [23]. There is possibly an adaptation of the vestibular system to the increased endolymphatic pressures, given that the time period for the development of hydrops is over months.…”

Section: Pressure Changes and Hydropsmentioning

confidence: 99%

Pathophysiology of Meniere's Disease

Mirza¹,

Gokhale²

2017

Up to Date on Meniere's Disease

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Meniere's disease, with its characteristic symptom triad of vertigo, balance and hearing disorders has yet to have its pathophysiology outlined conclusively. Any theory must elucidate all aspects of the natural progression, including vestibular and auditory symptoms. While the central dogma revolves around endolymphatic hydrops, this theory is not without laws, such as its inability to explain all the physiological changes seen in patients, or the often absence of symptoms. While several degenerative changes are observed in temporal bone histopathology, they do not necessarily explain the sequence of events in the development and progress of the disease. This chapter explores the pathophysiology of the disease, focusing on the hydrops theory, while presenting evidence for and against it. Various changes in the inner ear physiology such as pressure changes, ionic disequilibrium, endocochlear potentials; in human and animal models are described. Alternative explanations for symptoms are discussed. This chapter touches briely upon etiology associated with Meniere's (and hydrops), and aims to assist a deeper understanding of the relationship of the process to clinical and experimental indings. A clear understanding of the process guides not only the clinical management to improve quality of life but also the direction of future research endeavors.

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“…Recent values for perilymphatic pressure range from 1.2 to 4.7 cm H 2 O [7][8][9][10][11][12], while hydrostatic pressures in the scala media range from 1.2 to 4.1 cm H 2 O [7][8][9][10][11][12]. Most studies recorded no significant pressure difference between the endolymphatic compartment and the perilymphatic space.…”

Section: Introductionmentioning

confidence: 99%

Perilymphatic and Endolymphatic Pressure in the Normal Guinea Pig

Warmerdam¹,

Schröder²,

Wit³

et al. 1999

ORL

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Perilymphatic and endolymphatic pressures were measured consecutively in the normal guinea pig using a WPI 900A micropressure system. The mean (n = 10) perilymphatic and endolymphatic pressures were 2.26 and 2.31 cm H₂O, respectively. There was no statistically significant difference between the pressures of the endolymphatic and perilymphatic compartments. The measured values were within the range of pressures found in the literature.

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The measurement and manipulation of intralabyrinthine pressure in experimental endolymphatic hydrops

Cited by 54 publications

References 57 publications

Endolymphatic sac is involved in the regulation of hydrostatic pressure of cochlear endolymph

Endolymphatic sac is involved in the regulation of hydrostatic pressure of cochlear endolymph

Pathophysiology of Meniere's Disease

Perilymphatic and Endolymphatic Pressure in the Normal Guinea Pig

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