The endocochlear potential depends on two K + diffusion potentials and an electrical barrier in the stria vascularis of the inner ear
- 5 February 2008
- journal article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 105 (5), 1751-1756
- https://doi.org/10.1073/pnas.0711463105
Abstract
An endocochlear potential (EP) of +80 mV is essential for audition. Although the regulation of K(+) concentration ([K(+)]) in various compartments of the cochlear stria vascularis seems crucial for the formation of the EP, the mechanism remains uncertain. We have used multibarreled electrodes to measure the potential, [K(+)], and input resistance in each compartment of the stria vascularis. The stria faces two fluids, perilymph and endolymph, and contains an extracelluar compartment, the intrastrial space (IS), surrounded by two epithelial layers, the marginal cell (MC) layer and that composed of intermediate and basal cells. Fluid in the IS exhibits a low [K(+)] and a positive potential, called the intrastrial potential (ISP). We found that the input resistance of the IS was high, indicating this space is electrically isolated from the neighboring extracellular fluids. This arrangement is indispensable for maintaining positive ISP. Inhibiting the K(+) transporters of the stria by anoxia, ouabain, or bumetanide caused the [K(+)] of the IS to increase and the intracellular [K(+)] of MCs to decrease, reducing both the ISP and the EP. Calculations indicate that the ISP represents the K(+) diffusion potential across the apical membranes of intermediate cells through Ba(2+)-sensitive K(+) channels. The K(+) diffusion potential across the apical membranes of MCs also contributes to the EP. Because the EP depends on two K(+) diffusion potentials and an electrical barrier in the stria vascularis, interference with any of these elements can interrupt hearing.Keywords
This publication has 44 references indexed in Scilit:
- Connexin30 deficiency causes instrastrial fluid–blood barrier disruption within the cochlear stria vascularisProceedings of the National Academy of Sciences of the United States of America, 2007
- Molecular and Physiological Bases of the K+ Circulation in the Mammalian Inner EarPhysiology, 2006
- Compartmentalization established by claudin-11-based tight junctions in stria vascularis is required for hearing through generation of endocochlear potentialJournal of Cell Science, 2004
- Deafness inClaudin 11-Null Mice Reveals the Critical Contribution of Basal Cell Tight Junctions to Stria Vascularis FunctionJournal of Neuroscience, 2004
- Potassium ion recycling pathway via gap junction systems in the mammalian cochlea and its interruption in hereditary nonsyndromic deafnessMedical Molecular Morphology, 2000
- Ultrastructural localization of Na,K-ATPase in the gerbil cochlea.Journal of Histochemistry & Cytochemistry, 1995
- How the ear's works workNature, 1989
- Time course of anoxia-induced K+ concentration changes in the cochlea measured with K+ specific microelectrodesPflügers Archiv - European Journal of Physiology, 1977
- The fine structure of the stria vascularis of the cat inner earJournal of Anatomy, 1966
- DC Resting Potentials Inside the Cochlear PartitionThe Journal of the Acoustical Society of America, 1952