Lin Yi-Wen, Cheng Chao-Min, Leduc Philip R, Chen Chih-Cheng
Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
PLoS One. 2009;4(1):e4293. doi: 10.1371/journal.pone.0004293. Epub 2009 Jan 28.
While neural systems are known to respond to chemical and electrical stimulation, the effect of mechanics on these highly sensitive cells is still not well understood. The ability to examine the effects of mechanics on these cells is limited by existing approaches, although their overall response is intimately tied to cell-matrix interactions. Here, we offer a novel method, which we used to investigate stretch-activated mechanotransduction on nerve terminals of sensory neurons through an elastomeric interface.
METHODOLOGY/PRINCIPAL FINDINGS: To apply mechanical force on neurites, we cultured dorsal root ganglion neurons on an elastic substrate, polydimethylsiloxane (PDMS), coated with extracellular matrices (ECM). We then implemented a controlled indentation scheme using a glass pipette to mechanically stimulate individual neurites that were adjacent to the pipette. We used whole-cell patch clamping to record the stretch-activated action potentials on the soma of the single neurites to determine the mechanotransduction-based response. When we imposed specific mechanical force through the ECM, we noted a significant neuronal action potential response. Furthermore, because the mechanotransduction cascade is known to be directly affected by the cytoskeleton, we investigated the cell structure and its effects. When we disrupted microtubules and actin filaments with nocodozale or cytochalasin-D, respectively, the mechanically induced action potential was abrogated. In contrast, when using blockers of channels such as TRP, ASIC, and stretch-activated channels while mechanically stimulating the cells, we observed almost no change in action potential signalling when compared with mechanical activation of unmodified cells.
CONCLUSIONS/SIGNIFICANCE: These results suggest that sensory nerve terminals have a specific mechanosensitive response that is related to cell architecture.
虽然已知神经系统会对化学和电刺激作出反应，但力学对这些高度敏感细胞的影响仍未得到充分理解。尽管这些细胞的整体反应与细胞-基质相互作用密切相关，但现有方法限制了研究力学对这些细胞影响的能力。在此，我们提供了一种新颖的方法，用于通过弹性体界面研究感觉神经元神经末梢上的拉伸激活机械转导。
方法/主要发现：为了对神经突施加机械力，我们将背根神经节神经元培养在涂有细胞外基质（ECM）的弹性底物聚二甲基硅氧烷（PDMS）上。然后，我们使用玻璃微吸管实施了一种受控压痕方案，以机械刺激与微吸管相邻的单个神经突。我们使用全细胞膜片钳记录单个神经突胞体上的拉伸激活动作电位，以确定基于机械转导的反应。当我们通过ECM施加特定机械力时，我们注意到神经元动作电位有显著反应。此外，由于已知机械转导级联直接受细胞骨架影响，我们研究了细胞结构及其影响。当我们分别用诺考达唑或细胞松弛素-D破坏微管和肌动蛋白丝时，机械诱导的动作电位被消除。相比之下，在机械刺激细胞时使用诸如TRP、ASIC和拉伸激活通道等通道的阻滞剂，与未修饰细胞的机械激活相比，我们观察到动作电位信号几乎没有变化。
结论/意义：这些结果表明，感觉神经末梢具有与细胞结构相关的特定机械敏感反应。
