K+ cycling and the endocochlear potential.
نویسنده
چکیده
Sensory transduction in the cochlea and the vestibular labyrinth depends on the cycling of K+. In the cochlea, endolymphatic K+ flows into the sensory hair cells via the apical transduction channel and is released from the hair cells into perilymph via basolateral K+ channels including KCNQ4. K+ may be taken up by fibrocytes in the spiral ligament and transported from cell to cell via gap junctions into strial intermediate cells. Gap junctions may include GJB2, GJB3 and GJB6. K+ is released from the intermediate cells into the intrastrial space via the KCNJ10 K+ channel that generates the endocochlear potential. From the intrastrial space, K+ is taken up across the basolateral membrane of strial marginal cells via the Na+/2Cl-/K+ cotransporter SLC12A2 and the Na+/K+-ATPase ATP1A1/ATP1B2. Strial marginal cells secrete K+ across the apical membrane into endolymph via the K+ channel KCNQ1/KCNE1, which concludes the cochlear cycle. A similar K+ cycle exists in the vestibular labyrinth. Endolymphatic K+ flows into the sensory hair cells via the apical transduction channel and is released from the hair cells via basolateral K+ channels including KCNQ4. Fibrocytes connected by gap junctions including GJB2 may be involved in delivering K+ to vestibular dark cells. Extracellular K+ is taken up into vestibular dark cells via SLC12A2 and ATP1A1/ATP1B2 and released into endolymph via KCNQ1/KCNE1, which concludes the vestibular cycle. The importance of K+ cycling is underscored by the fact that mutations of KCNQ1, KCNE1, KCNQ4, GJB2, GJB3 and GJB6 lead to deafness in humans and that null mutations of KCNQ1, KCNE1, KCNJ10 and SLC12A2 lead to deafness in mouse models.
منابع مشابه
Supporting sensory transduction: cochlear fluid homeostasis and the endocochlear potential.
The exquisite sensitivity of the cochlea, which mediates the transduction of sound waves into nerve impulses, depends on the endocochlear potential and requires a highly specialized environment that enables and sustains sensory function. Disturbance of cochlear homeostasis is the cause of many forms of hearing loss including the most frequently occurring syndromic and non-syndromic forms of her...
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Marcus, Daniel C., Tao Wu, Philine Wangemann, and Paulo Kofuji. KCNJ10 (Kir4.1) potassium channel knockout abolishes the endocochlear potential. Am J Physiol Cell Physiol 282: C403–C407, 2002; 10.1152/ajpcell.00312.2001.— Stria vascularis of the cochlea generates the endocochlear potential and secretes K . K is the main charge carrier and the endocochlear potential the main driving force for th...
متن کاملKCNJ10 (Kir4.1) potassium channel knockout abolishes endocochlear potential.
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ورودعنوان ژورنال:
- Hearing research
دوره 165 1-2 شماره
صفحات -
تاریخ انتشار 2002