DISPLACEMENT-CLAMP MEASUREMENT OF THE FORCES EXERTED BY GATING SPRINGS IN THE HAIR BUNDLE
DISPLACEMENT-CLAMP MEASUREMENT OF THE FORCES EXERTED BY GATING SPRINGS IN THE HAIR BUNDLE
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DOI：
10.1073/pnas.90.4.1330
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发表时间：
1993-02-15
影响因子：
11.1
通讯作者：
HUDSPETH, AJ
中科院分区：
文献类型：
--
作者：
JARAMILLO, F;HUDSPETH, AJ
施加到毛细胞的毛束的机械刺激通过门控弹簧（gating spring）传送到转导通道，门控弹簧是当毛束朝向其高边缘移位时拉伸的弹性元件。为了量化门控弹簧施加的力的大小和时间依赖性，我们已经开发了一种位移夹具系统，该系统约束束的运动，同时测量束在适应机械刺激期间产生的力，响应于通道阻塞，以及门控弹簧的破坏。我们的研究结果表明，每个门控弹簧施加的张力几乎等于8 pN的休息束，并能维持至少4-13 pN的额外的张力。实验提供了进一步的证据，门控弹簧占毛束的动态刚度的至少三分之一，并且几乎等于100 fN的力足以打开单个换能通道。
Mechanical stimuli applied to the hair bundle of a hair cell are communicated to the transduction channels by gating springs, elastic elements that are stretched when the bundle is displaced toward its tall edge. To quantify the magnitude and time dependence of the forces exerted by gating springs, we have developed a displacement-clamp system that constrains a bundle's motion while measuring the forces that the bundle produces during adaptation to mechanical stimuli, in response to channel blockage, and upon destruction of the gating springs. Our results suggest that each gating spring exerts a tension of almost-equal-to 8 pN in the resting bundle and can sustain at least 4-13 pN of additional tension. The experiments provide further evidence that the gating springs account for at least one-third of the hair bundle's dynamic stiffness and that a force of almost-equal-to 100 fN is sufficient to open a single transduction channel.