Alvarez J, Torres J C
J Theor Biol. 1985 Feb 7;112(3):627-51. doi: 10.1016/s0022-5193(85)80028-x.
Ribosomes have not been observed in axoplasm. This had led to the notions that the perikaryon is the only source of neuronal proteins and that the axoplasm is supplied by a (slow) transport mechanism. However, we question these two notions because they are unable to give an account of real neurones in accordance with the body of biological knowledge. We point out, for example, that the synthetic rate of perikarya or the life span of axoplasmic proteins should be beyond known ranges for animal cells and that a uniform axon is unlikely to result if it is fed from one end. We propose an alternative view for the maintenance of the axon which accepts the controversial idea of axoplasmic synthesis of proteins; as a result, the slow transport becomes unnecessary. Our view gives a qualitative account of the observations dealing with the maintenance of the axoplasm. To account for the phenomenology in a more quantitative fashion, a computer simulation was carried out where the equations of the program provided only for axoplasmic synthesis of proteins; the set of curves retrieved were in good agreement with experimental findings believed so far to support the notion of slow transport. In conclusion, we think that the notion of "slow axoplasmic transport" has been a misinterpretation of good observations because the frame of reference was incomplete in not providing for axoplasmic synthesis of proteins.
在轴浆中尚未观察到核糖体。这导致了这样的观点，即胞体是神经元蛋白质的唯一来源，轴浆是由一种（缓慢的）运输机制提供的。然而，我们对这两个观点提出质疑，因为根据生物学知识体系，它们无法解释真实的神经元。例如，我们指出，胞体的合成速率或轴浆蛋白的寿命应该超出动物细胞已知的范围，而且如果轴突从一端获取营养，不太可能形成均匀的轴突。我们提出了一种关于轴突维持的替代观点，该观点接受了有争议的轴浆蛋白质合成观点；因此，缓慢运输变得不必要。我们的观点对涉及轴浆维持的观察结果进行了定性解释。为了更定量地解释这种现象学，我们进行了计算机模拟，程序方程仅考虑轴浆蛋白质合成；得到的一组曲线与迄今为止被认为支持缓慢运输观点的实验结果高度吻合。总之，我们认为“轴浆缓慢运输”的观点是对良好观察结果的错误解读，因为参考框架不完整，没有考虑轴浆蛋白质合成。
