Osmotic dilution stimulates axonal outgrowth by making axons more sensitive to tension.
Osmotic dilution stimulates axonal outgrowth by making axons more sensitive to tension.
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DOI：
10.1016/0021-9290(95)00091-7
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发表时间：
1995-12
影响因子：
2.4
通讯作者：
C. Lin;P. Lamoureux;R. Buxbaum;S. Heidemann
中科院分区：
文献类型：
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作者：
C. Lin;P. Lamoureux;R. Buxbaum;S. Heidemann
机械张力是轴突生长速度的有力刺激因素，渗透稀释也会刺激轴突生长。我们希望确定渗透刺激和轴突生长的张力调节之间的关系。我们使用校准的玻璃针对培养的鸡感觉神经元施加恒定的力来延长轴突。我们发现，在培养液中加入50%的无机离子稀释后，以恒定的力拉出的轴突生长速度将加快50%-300%。也就是说，渗透稀释似乎会导致轴突对外加压力的敏感度增加。实验干预表明，这种作用不是由细胞外钙的稀释、腺苷环化酶的渗透刺激或机械敏感离子通道的渗透刺激介导的。相反，测量通常由轴突承受的静态张力的实验表明，对轴突干的细胞骨架蛋白质有直接的机械作用。我们的结果与轴突生长的正式热力学模型是一致的，在该模型中，去除轴突微管上的压缩负荷会促进它们的组装，从而促进轴突延长。
Mechanical tension is a potent stimulator of axonal growth rate, which is also stimulated by osmotic dilution. We wished to determine the relationship, if any, between osmotic stimulation and tensile regulation of axonal growth. We used calibrated glass needles to apply constant force to elongate axons of cultured chick sensory neurons. We find that a neurite being pulled at a constant force will grow 50–300% faster following a 50% dilution of inorganic ions in the culture medium. That is, osmotic dilution appears to cause axons to increase their sensitivity to applied tensions. Experimental interventions suggest that this effect is not mediated by dilution of extracellular calcium, or to osmotic stimulation of adenylate cyclase, or to osmotic stimulation of mechanosensitive ion channels. Rather, experiments measuring the static tension normally borne by neurites suggest a direct mechanical effect on the cytoskeletal proteins of the neurite shaft. Our results are consistent with a formal thermodynamic model for axonal growth in which removing a compressive load on axonal microtubules promotes their assembly, thus promoting axonal elongation.