Ion channels in basolateral membrane of marginal cells dissociated from gerbil stria vascularis

Takeuchi, Shunji; Ando, Motonori; Kozakura, Kenichi; Saito, Haruo; Irimajiri, Akihiko

doi:10.1016/0378-5955(94)00191-r

Cited by 55 publications

(29 citation statements)

References 31 publications

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“…In this model, the involvement of marginal cells in the generation of EP was limited to the maintenance of the low K + concentration in the intrastrial space. Recent detailed electrophysiological data appear to favor the two-cell model Takeuchi et al, 1995;Takeuchi et al, 2000;Marcus et al, 2002), but it was technically difficult to evaluate conclusively the importance of the compartmentalization in the stria vascularis for the EP generation.…”

Section: Discussionmentioning

confidence: 99%

Compartmentalization established by claudin-11-based tight junctions in stria vascularis is required for hearing through generation of endocochlear potential

Kitajiri

Miyamoto

Mineharu

et al. 2004

Journal of Cell Science

150

139

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Claudins are cell adhesion molecules working at tight junctions (TJs) that are directly involved in compartmentalization in multicellular organisms. The cochlea includes a rather peculiar compartment filled with endolymph. This compartment is characterized by high K+ concentration (∼150 mM) and a positive endocochlear potential (∼90 mV; EP), both indispensable conditions for cochlear hair cells to transduce acoustic stimuli to electrical signals. These conditions are thought to be generated by the stria vascularis, which is adjacent to the endolymph compartment. The stria vascularis itself constitutes an isolated compartment delineated by two epithelial barriers, marginal and basal cell layers. Because TJs of basal cells are primarily composed of claudin-11, claudin-11-deficient (Cld11-/-) mice were generated with an expectation that the compartmentalization in stria vascularis in these mice would be affected. Auditory brainstem response measurements revealed that Cld11-/- mice suffered from deafness; although no obvious gross morphological malformations were detected in Cld11-/- cochlea, freeze-fracture replica electron microscopy showed that TJs disappeared from basal cells of the stria vascularis. In good agreement with this, tracer experiments showed that the basal cell barrier was destroyed without affecting the marginal cell barrier. Importantly, in the endolymph compartment of Cld11-/- cochlea, the K+ concentration was maintained around the normal level (∼150 mM), whereas the EP was suppressed down to ∼30 mV. These findings indicated that the establishment of the stria vascularis compartment, especially the basal cell barrier, is indispensable for hearing ability through the generation/maintenance of EP but not of a high K+ concentration in the endolymph.

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Section: Discussionmentioning

confidence: 99%

Compartmentalization established by claudin-11-based tight junctions in stria vascularis is required for hearing through generation of endocochlear potential

Kitajiri

Miyamoto

Mineharu

et al. 2004

Journal of Cell Science

150

139

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“…3A). Intermediate cells are a type of melanocytes (27,82). Thus isolated intermediated cells could be identified with the melanin pigments.…”

Section: Fig 2 Expression and Distribution Of Hmentioning

confidence: 99%

“…The temporal bones of anesthetized mice were removed, and the stria vascularis was dissociated. Tissue strips of stria vascularis were incubated for 30 min at 25°C in a normal Tyrode solution (136.5 mM NaCl, 5.4 mM KCl, 1.8 mM CaCl 2, 0.53 mM MgCl2, 5.5 mM glucose, and 5.0 mM HEPES-NaOH buffer, pH 7.4) containing 0.2% trypsin and then disrupted mechanically with pipetting (82).…”

Section: Animalsmentioning

confidence: 99%

Gastric type H⁺,K⁺-ATPase in the cochlear lateral wall is critically involved in formation of the endocochlear potential

Shibata

Hibino²,

Doi³

et al. 2006

American Journal of Physiology-Cell Physiology

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Cochlear endolymph has a highly positive potential of approximately +80 mV known as the endocochlear potential (EP). The EP is essential for hearing and is maintained by K+ circulation from perilymph to endolymph through the cochlear lateral wall. Various K+ transport apparatuses such as the Na+,K+-ATPase, the Na+-K+-2Cl− cotransporter, and the K+ channels Kir4.1 and KCNQ1/KCNE1 are expressed in the lateral wall and are known to play indispensable roles in cochlear K+ circulation. The gastric type of the H+,K+-ATPase was also shown to be expressed in the cochlear lateral wall (Lecain E, Robert JC, Thomas A, and Tran Ba Huy P. Hear Res 149: 147–154, 2000), but its functional role has not been well studied. In this study we examined the precise localization of H+,K+-ATPase in the cochlea and its involvement in formation of EP. RT-PCR analysis showed that the cochlea expressed mRNAs of gastric α1-, but not colonic α2-, and β-subunits of H+,K+-ATPase. Immunolabeling of an antibody specific to the α1 subunit was detected in type II, IV, and V fibrocytes distributed in the spiral ligament of the lateral wall and in the spiral limbus. Strong immunoreactivity was also found in the stria vascularis. Immunoelectron microscopic examination exhibited that the H+,K+-ATPase was localized exclusively at the basolateral site of strial marginal cells. Application of Sch-28080, a specific inhibitor of gastric H+,K+-ATPase, to the spiral ligament as well as to the stria vascularis caused prominent reduction of EP. These results may imply that the H+,K+-ATPase in the cochlear lateral wall is crucial for K+ circulation and thus plays a critical role in generation of EP.

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“…It has been reported that the intracellular potential of marginal cells is about ϩ80 to ϩ90 mV and that the electrical potential across the luminal membrane is very small or nearly 0 mV [3,28]. Therefore, it is easy for Ca 2ϩ to leak out passively from cell to endolymph when [Ca] [29][30][31]. On the other hand it has recently been reported that some non-selective cation channels, such as the transient receptor potential channel (TRP channel), are highly permeable to Ca 2ϩ and belong to family of epithelial Ca 2ϩ channels [25].…”

Section: Fig 9 Time Course Of Changes In [Na] E and Ep (A) Or (Ph) mentioning

confidence: 99%

Asphyxia and Diuretic-Induced Changes in the Ca2+ Concentration of Endolymph.

Takamaki

Mori

Araki

et al. 2003

JJP

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Ion channels in basolateral membrane of marginal cells dissociated from gerbil stria vascularis

Cited by 55 publications

References 31 publications

Compartmentalization established by claudin-11-based tight junctions in stria vascularis is required for hearing through generation of endocochlear potential

Compartmentalization established by claudin-11-based tight junctions in stria vascularis is required for hearing through generation of endocochlear potential

Gastric type H⁺,K⁺-ATPase in the cochlear lateral wall is critically involved in formation of the endocochlear potential

Asphyxia and Diuretic-Induced Changes in the Ca2+ Concentration of Endolymph.

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Ion channels in basolateral membrane of marginal cells dissociated from gerbil stria vascularis

Cited by 55 publications

References 31 publications

Compartmentalization established by claudin-11-based tight junctions in stria vascularis is required for hearing through generation of endocochlear potential

Compartmentalization established by claudin-11-based tight junctions in stria vascularis is required for hearing through generation of endocochlear potential

Gastric type H+,K+-ATPase in the cochlear lateral wall is critically involved in formation of the endocochlear potential

Asphyxia and Diuretic-Induced Changes in the Ca2+ Concentration of Endolymph.

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Gastric type H⁺,K⁺-ATPase in the cochlear lateral wall is critically involved in formation of the endocochlear potential