Mechanism of the Production of the Negative Endocochlear DC Potential in the Guinea Pig

Komune, Shizuo; Huangfu, Musan; Snow, James B.

doi:10.1177/019459988309100416

Cited by 17 publications

(10 citation statements)

References 15 publications

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“…2). This indicates an increase in the K+ conductance in the cells of the organ of Corti during anoxia [20,22], The electrochemical gra dient for Na+ was directed toward the scala media and became greater at the luminal membrane than at the baso lateral membrane. This may account for the increase of Na+ activities in the scala media and marginal cells.…”

Section: Discussionmentioning

confidence: 97%

Movement of Monovalent Ions across the Membranes of Marginal Cells of the Stria vascularis in the Guinea Pig Cochlea

Komune¹,

Nakagawa²,

Hisashi³

et al. 1993

ORL

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The resting potential and monovalent ions in the marginal cells and scala media were measured before and 20 min after the onset of anoxia using ionsensitive microelectrodes. The resting potential of the marginal cells decreased from 62.7 to ––2.4 mV. The K⁺ activity decreased from 77.7 to 53.2 mEq/l, while the Na⁺ activity increased from 2.6 to 24.7 mEq/l. The Cl^–– activity did not change significantly. In the scala media, the endocochlear potential decreased rapidly from 80.9 to ––28.0 mV after the onset of anoxia. The K⁺ activity decreased from 119.0 to 96.5 mEq/l, the Na⁺ activity increased from 1.3 to 9.5 mEq/l and that of Cl^–– decreased from 127.0 to 115.1 mEq/l. The electrochemical gradients determined for each ion based on the ionic changes in the scala media and marginal cells, suggested the existence of an Na/K pump and Na-K-2Cl cotransport at the basolateral membrane of the marginal cells, and a rheogenic K pump and Na-K-2Cl transport at the luminal membrane of the marginal cells. The Na⁺ and K⁺ must be recycled at the basolateral membrane and luminal membrane of marginal cells, respectively.

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Section: Discussionmentioning

confidence: 97%

Movement of Monovalent Ions across the Membranes of Marginal Cells of the Stria vascularis in the Guinea Pig Cochlea

Komune¹,

Nakagawa²,

Hisashi³

et al. 1993

ORL

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“…Values arc means ± SD. which may be amplified via the organ of Corti by the effect of anoxia in the normal guinea pigs, but not in the kanamvein-deafened guinea pigs because of a loss of hair cells [17], This result resembles that in the kanamycindcafened guinea pigs shown in figure 6 in that the regres sion line intercepts around 10-20 mV at the y axis. Fig ure 8 shows the effect of anoxia on the relationship between eleetrogenic potential and K+ active transport.…”

Section: Electrogenic Potential Vs Active K+ Transportmentioning

confidence: 62%

“…It is therefore conceivable that the EP is the sum of the two components. However, alterna tive mechanisms for the EP have been proposed by other investigators [10][11][12][13][14][15][16][17], Several investigators studied waltz ing guinea pigs or kanamycin-treated guinea pigs, be cause. in those models, the animals' hair cells are de stroyed but the stria vascularis cells remain virtually intact [11.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, the two-component theory of Kuijpers and Bontings [1] does not completely explain why a negative EP was not registered during anoxia in the kanamycindeafened guinea pigs, whereas the steady-state EP did not differ significantly between the two groups. Arguments against the negative EP being a pre-existing K+ diffusion potential have been presented by several investigators [10][11][12][13][14][15][16][17], These studies suggest that the negative EP may not be pre-existing potential but a potential produced only during the administration of loop diuretics or anox ia. Komune el al.…”

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confidence: 99%

“…Komune el al. [ 17] proposed an alternative hypothesis that the EP fundamentally consists of two components, a positive (80-90 mV) and a small negative ion diffusion potential in the steady state in normal and kanamycindeafened guinea pigs, but which is amplified by the increase in K+ conductance through the organ of Corti during anoxia in the normal but not in the kanamycindeafened guinea-pigs, due to a loss of the hair cells. The experiment by Marcus [26] may support our concept, which demonstrated that a high K+ in the scala tympani caused a minor change of EP.…”

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Validity of the Two-Component Theory in the Production of Endocochlear Potential

Komune

Kimitsuki

Nakagawa³

et al. 1993

ORL

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To evaluate the mechanism of endocochlear potential (EP) and the validity of the two-component theory in its production, we perfused the endolymphatic space of normal and kanamycin-deafened guinea pigs with artificial endolymph containing 50 mM K⁺. The K⁺ activities and EP were simultaneously measured with a double-barreled K⁺ electrode during and after perfusion. The relationship between the mangitude of the electrogenic potential and K⁺ active transport was calculated and compared between the two groups of animals. The results showed that the positive component of the EP (positive EP) was mainly dependent on K⁺ active transport in the stria vascularis but included other electrogenic components not dependent on K+ active transport. The K⁺ and Na⁺ conductances (Gk and Gna) between the endolymph and perilymph were also calculated in the normal and kanamycin-deafened guinea pigs. The Gk was much lower in kanamycin-deafened guinea pigs but the Gna did not differ between the two groups of animals. The theoretical EP value during anoxia (negative EP) was consistent with that observed in each group. The difference in the negative EP was approximately 30 mV, but the steady-state EP did not differ between groups. It is concluded that EP is probably not the simple mathematical sum of the positive and negative potentials but involves more complex mechanisms.

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Profiles of resting potentials across the stria vascularis in kanamycin-deafened guinea pigs

Komune

Inoue

Wakizono

et al. 1994

Eur Arch Otorhinolaryngol

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The resting potentials of the marginal cells in the stria vascularis of the guinea pig were determined from changes in the combined electrode-tissue resistance of the electrode. The resistance of the electrode was 45.5 +/- 16.0 M omega (n = 20) before penetration of the stria vascularis and 46.7 +/- 17.3 M omega (n = 20) after penetration. The resistance drops across the luminal membrane of the marginal cells were 46.0 +/- 22.6 M omega (n = 12) in kanamycin-deafened guinea pigs and 54.5 +/- 33.1 M omega (n = 9) in normal guinea pigs. The endocochlear potential (EP) and resting potentials in the marginal cells were 90.1 +/- 6.0 mV (n = 14) and 70.4 +/- 11.3 mV (n = 14) in kanamycin-deafened guinea pigs and 84.8 + 5.1 mV (n = 29) and 74.7 +/- 11.7 mV (n = 29) in normal guinea pigs. The resting potentials in the marginal cells decreased gradually and were approximately 0 mV around 20 min after anoxia in both kanamycin-deafened and normal guinea pigs. These changes were comparable to those of EP in kanamycin-deafened guinea pigs during anoxia. The mechanism of the EP in kanamycin-deafened guinea pigs is discussed.

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Mechanism of the Production of the Negative Endocochlear DC Potential in the Guinea Pig

Cited by 17 publications

References 15 publications

Movement of Monovalent Ions across the Membranes of Marginal Cells of the Stria vascularis in the Guinea Pig Cochlea

Movement of Monovalent Ions across the Membranes of Marginal Cells of the Stria vascularis in the Guinea Pig Cochlea

Validity of the Two-Component Theory in the Production of Endocochlear Potential

Profiles of resting potentials across the stria vascularis in kanamycin-deafened guinea pigs

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