Gap junctions and hearing loss
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maintenance of the high K+ concentration in the endolymph and of the endocochlear potential requires a highly developed tight junction system surrounding the scala media
- most obvious examples are in the cuticular plate region of the organ of Corti and in Reissner’s membrane
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there is also a mechanism to recycle K+ back to the stria vascularis after it passes through the hair cells (to prevent high levels of K+ in the extracellular space surrounding the dendrites of the spiral ganglion neurons)
- supporting cells have gap junctions that allow K+ to return to the stria vascularis
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mutations in 4 different connexin genes (26, 30, 31 and 43) have been found to underlie at least 12 different cochlear pathologies
- the most common cause of sensorineural hearing loss in American/European populations is a defect in Cx26