Effect of Norepinephrine on Ouabain-sensitive, K+-dependentp-Nitrophenylphosphatase Activity in Strial Marginal Cells of the Cochlea in Normal and Reserpinized Guinea Pigs

Kanoh, Naoyuki

doi:10.1080/00016489850182503

Cited by 2 publications

(1 citation statement)

References 17 publications

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“…The function of the ß 2 -adrenergic receptors in the nonstrial lateral wall tissues is currently unclear. ß 1 -Adrenergic receptors in stria vascularis, however, appear to control the rate of metabolism [Ishii et al, 2000] and the activity of Na + /K + ATPase [Kanoh, 1998[Kanoh, , 1999. Most importantly, ß 1 -adrenergic receptors in stria vascularis control the rate of transepithelial K + secretion [Wangemann et al, 2000].…”

Section: Regulation Of K + Cyclingmentioning

confidence: 99%

K+ Cycling and Its Regulation in the Cochlea and the Vestibular Labyrinth

Wangemann

2002

Audiol Neurotol

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Potassium (K⁺) plays a very important role in the cochlea. K⁺ is the major cation in endolymph and the charge carrier for sensory transduction and the generation of the endocochlear potential. The importance of K⁺ handling in the cochlea is marked by the discovery of several forms of hereditary deafness that are due to mutations of K⁺ channels. Deafness results from mutations of KCNQ4, a K⁺ channel in the sensory hair cells, as well as from mutations of the gap junction proteins GJB2, GJB3 and GJB6 that may facilitate cell-to-cell movements of K⁺. Deafness results also from mutations of KCNQ1 or KCNE1, subunits of a K⁺ channel that carries K⁺ from strial marginal cells and vestibular dark cells into endolymph. Further, deafness results from mutations of KCNJ10, a K⁺ channel that generates the endocochlear potential in conjunction with the high K⁺ concentration in strial intermediate cells and the low K⁺ concentration in the intrastrial fluid spaces. This review details recent advances in the understanding of K⁺ transport and its regulation in the cochlea and the vestibular labyrinth.

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Section: Regulation Of K + Cyclingmentioning

confidence: 99%

K+ Cycling and Its Regulation in the Cochlea and the Vestibular Labyrinth

Wangemann

2002

Audiol Neurotol

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How Useful Is Corticosteroid Treatment in Cochlear Disorders?

Lamm¹,

Arnold²

1999

Otorhinolaryngol Nova

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The scientific basis for the administration of corticosteroids classified as glucocorticoids in certain cochlear disorders, such as immune-mediated progressive and idiopathic acute sensorineural hearing loss (SNHL), Ménière’s disease and noise-induced hearing loss (NIHL), was discussed. The current knowledge on the physiological functions of endogenous glucocorticoids and the pharmacological effects of their synthetic analogs was summarized. Emphasis was placed on experimental studies on corticosteroids in the cochleovestibular system and on the therapeutic effects of glucocorticoids on SNHL, Ménière’s disease, NIHL and chronic tinnitus obtained from clinical trials. Glucocorticoids exert numerous profound effects on almost every organ system, including mechanisms involved in anti-inflammatory action and immunosuppression. However, inflammatory tissue alterations are not only elicited by bacterial, viral or other immunopathological processes but also by physically and chemically induced cellular damage, tissue ischemia and hypoxia. Regardless of whether one or more of these insults underlie SNHL, Ménière’s disease and NIHL, glucocorticoids effectively counteract subsequent inflammatory tissue damage in the auditory and vestibular system. This was confirmed in experimental studies on immune-mediated progressive SNHL, and thrombosis-induced and noise-induced cochlear ischemia, hypoxia and hearing loss. Glucocorticoid treatment results of immune-mediated progressive and acute idiopathic SNHL are promising, although placebo-controlled trials on the effect in acute idiopathic SNHL have revealed conflicting data (probably due to the small number of patients). Clinical studies on the effect of systemic glucocorticoid monotherapy on Ménière’s disease and NIHL have not yet been performed. After intratympanic application, relief of vertigo, tinnitus and preservation of hearing in Ménière’s disease was observed in previous studies; however, recently none of these effects have been confirmed in a placebo-controlled trial. Similarly, in contrast to previous reports, chronic tinnitus of various origins did not improve after repetitive glucocorticoid application onto the round window membrane using a micropump connected to an implanted microcatheter.

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Effect of Norepinephrine on Ouabain-sensitive, K⁺-dependentp-Nitrophenylphosphatase Activity in Strial Marginal Cells of the Cochlea in Normal and Reserpinized Guinea Pigs

Cited by 2 publications

References 17 publications

K<sup>+</sup> Cycling and Its Regulation in the Cochlea and the Vestibular Labyrinth

K<sup>+</sup> Cycling and Its Regulation in the Cochlea and the Vestibular Labyrinth

How Useful Is Corticosteroid Treatment in Cochlear Disorders?

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