Letourneau P C
J Neurosci. 1982 Jun;2(6):806-14. doi: 10.1523/JNEUROSCI.02-06-00806.1982.
In order to examine the continuity of individual microtubules in growing neurites, microtubules were observed and counted in whole mounted cytoskeletons of chick embryo sensory neurons. At neurite branch points, the microtubules of the proximal segment are divided between the distal segments without the addition of microtubules to the distal branches. Few microtubules ends were seen in the cytoskeletons, and on occasion, the same number of microtubules was counted at widely separated points along a neurite segment. I conclude that microtubules are long in embryonal neurites, and some may extend the entire length from perikaryon to neurite tip. This may limit where microtubule growth occurs to the perikaryon and the neurite tip, where many microtubule ends are. In addition, the great length of most neuritic microtubules may explain why collateral sprouting is rare along embryonal neurites.
为了检测生长中的神经突中单个微管的连续性，在鸡胚感觉神经元的全装细胞骨架中观察并计数微管。在神经突分支点，近端节段的微管在远端节段之间分配，而远端分支没有微管的添加。在细胞骨架中很少看到微管末端，偶尔，沿着神经突节段在相距很远的点计数到相同数量的微管。我得出结论，胚胎神经突中的微管很长，有些可能从胞体延伸到神经突尖端的整个长度。这可能将微管生长发生的位置限制在胞体和神经突尖端，即许多微管末端所在的位置。此外，大多数神经突微管的长度很长，这可以解释为什么胚胎神经突很少发生侧支发芽。
