DIRECT EVIDENCE THAT GROWTH CONES PULL
DIRECT EVIDENCE THAT GROWTH CONES PULL
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DOI：
10.1038/340159a0
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发表时间：
1989-01-01
期刊：
影响因子：
--
通讯作者：
HEIDEMANN S R
中科院分区：
文献类型：
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作者：
LAMOUREUX P;BUXBAUM R E;HEIDEMANN S R
关于轴突的伸长是否是生长锥拉动的结果以及张力在轴突伸长中的作用还存在争议。本世纪初，人们的共识是轴突或神经突因生长锥向前运动产生的张力而伸长5，6。据推测，收缩的丝状伪足是移动生长锥的张力的来源7，8。但这一观点受到了实验的挑战，实验表明，在细胞松弛素的存在下，神经突会伸长，尽管是异常的，细胞松弛素会抑制生长锥和丝状伪足的运动9。此外，生长锥活动的高分辨率、视频增强观察反对将丝状伪足缩短作为张力的来源，这表明细胞质的挤出而不是拉动过程是神经突伸长的关键事件1，3。然而，对慢轴突运输的研究10表明，慢得多的细胞骨架推动是轴突伸长的基础。我们在这里报告的神经突力的生长锥前进的函数，这表明它们是线性相关的，并伴随着明显的神经突生长的直接测量。在生长锥不能前进的神经突中，力没有增加。
THERE is controversy over whether axonal elongation is the result of a pulling growth cone and the role of tension in axonal elongationl-4. Earlier in this decade, the consensus was that axons or neurites elongated from tension generated by forward motility of the growth cone5,6. It was presumed that contractile filopodia were the source of the tension moving the growth cone7,8. But this view was challenged by experiments showing that neurites elongate, albeit abnormally, in the presence of cytochalasin, which inhibits growth-cone and filopodial movements9. Additionally, high resol-ution, video-enhanced observations of growth-cone activity argued against filopodial shortening as a source of tension, suggesting instead that an extrusion of cytoplasm rather than a pulling process, is the key event in neurite elongation1,3. Studies of slow axonal transport10, however, indicate that much slower cytoskeletal pushing underlies axonal elongation. We report here direct measurements of neurite force as a function of growth-cone advance which show that they are linearly related and accompanied by apparent neurite growth. No increase in force occurs in neurites whose growth cone fails to advance.