Physiological effects of tip link destruction in cochlear hair cells. Implications for noise-induced damage of the inner ear

Sound overexposure is known to cause damage to cochlear structures and can induce permanent or temporary hearing loss and tinnitus. Perhaps the most sensitive of these structures to sound overexposure are the tip links. In this paper the electrophysiological effects of pharmacological destruction of the rip links of outer hair cells was investigated. Outer hair cells treated with elastase (20 U/mL) or BAPTA (5 mM) no longer responded to sinusoidal stimuli. in contrast to common belief, transduction channels opened due to loss of tip links. Such opened channels can allow K+ and Ca2+ to enter the cell from the endolymphatic space and could lead to permanent depolarization. This influx of cations caused by loss of tip links, together with the subsequent hair-cell depolarization,might be a source of sensorineural hearing loss and tinnitus associated with acoustic trauma.