Zhao Y, Yamoah E N, Gillespie P G
Department of Physiology, Johns Hopkins University, Baltimore, MD 21205, USA.
Proc Natl Acad Sci U S A. 1996 Dec 24;93(26):15469-74. doi: 10.1073/pnas.93.26.15469.
A hair cell's tip links are thought to gate mechanoelectrical transduction channels. The susceptibility of tip links to acoustic trauma raises questions as to whether these fragile structures can be regenerated. We broke tip links with the calcium chelator 1,2-bis(O-aminophenoxy) ethane-N,N,N',N'-tetraacetic acid and found that they can regenerate, albeit imperfectly, over several hours. The time course of tip-link regeneration suggests that this process may underlie recovery from temporary threshold shifts induced by noise exposure. Cycloheximide does not block tip-link regeneration, indicating that new protein synthesis is not required. The calcium ionophore ionomycin prevents regeneration, suggesting regeneration normally may be stimulated by the reduction in stereociliary Ca2+ when gating springs rupture and transduction channels close. Supporting the equivalence of tip links with gating springs, mechanoelectrical transduction returns over the same time period as tip links; strikingly, adaptation is substantially reduced, even 24 hr after breaking tip links.
毛细胞的纤毛顶部连接被认为是机械电转导通道的门控结构。纤毛顶部连接对声损伤的易感性引发了关于这些脆弱结构能否再生的疑问。我们用钙螯合剂1,2 - 双（O - 氨基苯氧基）乙烷 - N,N,N',N' - 四乙酸破坏了纤毛顶部连接，发现它们能够在数小时内再生，尽管并不完美。纤毛顶部连接再生的时间进程表明，这一过程可能是噪声暴露引起的暂时性阈移恢复的基础。放线菌酮并不阻断纤毛顶部连接的再生，这表明不需要新的蛋白质合成。钙离子载体离子霉素可阻止再生，这表明当门控弹簧断裂且转导通道关闭时，通常可能通过静纤毛Ca2+的减少来刺激再生。支持纤毛顶部连接与门控弹簧等效的是，机械电转导在与纤毛顶部连接相同的时间段内恢复；令人惊讶的是，即使在破坏纤毛顶部连接24小时后，适应也显著降低。
