静态球囊毛细胞束表现出的机械放大作用。
Mechanical amplification exhibited by quiescent saccular hair bundles.
作者信息
Roongthumskul Yuttana, Bozovic Dolores
机构信息
Department of Physics and Astronomy, University of California, Los Angeles, Los Angeles, California.
Department of Physics and Astronomy, University of California, Los Angeles, Los Angeles, California; California NanoSystems Institute, University of California, Los Angeles, Los Angeles, California.
出版信息
Biophys J. 2015 Jan 6;108(1):53-61. doi: 10.1016/j.bpj.2014.11.009.
Spontaneous oscillations exhibited by free-standing hair bundles from the Bullfrog sacculus suggest the existence of an active process that might underlie the exquisite sensitivity of the sacculus to mechanical stimulation. However, this spontaneous activity is suppressed by coupling to an overlying membrane, which applies a large mechanical load on the bundle. How a quiescent hair bundle utilizes its active process is still unknown. We studied the dynamics of motion of individual hair bundles under different offsets in the bundle position, and observed the occurrence of spikes in hair-bundle motion, associated with the generation of active work. These mechanical spikes can be evoked by a sinusoidal stimulus, leading to an amplified movement of the bundle with respect to the passive response. Amplitude gain reached as high as 100-fold at small stimulus amplitudes. Amplification of motion decreased with increasing amplitude of stimulation, ceasing at ∼6-12 pN stimuli. Results from numerical simulations suggest that the adaptation process, mediated by myosin 1c, is not required for the production of mechanical spikes.
牛蛙球囊独立毛束所表现出的自发振荡表明存在一种主动过程，该过程可能是球囊对机械刺激具有极高敏感性的基础。然而，这种自发活动会因与覆盖膜耦合而受到抑制，覆盖膜会对毛束施加较大的机械负荷。静止的毛束如何利用其主动过程仍是未知的。我们研究了不同毛束位置偏移下单个毛束的运动动力学，并观察到毛束运动中尖峰的出现，这与主动功的产生相关。这些机械尖峰可由正弦刺激诱发，导致毛束相对于被动响应产生放大运动。在小刺激幅度下，幅度增益高达100倍。运动放大随着刺激幅度的增加而减小，在约6 - 12 pN刺激时停止。数值模拟结果表明，由肌球蛋白1c介导的适应过程并非产生机械尖峰所必需。
Zotero 插件