Lázár G
Neuroscience. 1982;7(11):2829-39. doi: 10.1016/0306-4522(82)90105-1.
Radioactivity above background level can be detected in the contralateral visual pathway of normal rats as long as 250 days after intraocular injection of tritiated proline. Silver grains disappear first from the retina, and last from the superior colliculus. In the optic tectum and the isthmic nucleus of the frog, more than 500 days are necessary to reach background level of radioactivity, when labelled retinal fibres are undergoing Wallerian degeneration. The intensity of label in tectal laminae formed by myelinated fibres is markedly reduced 12 days after the removal of the labelled eye. In the laminae of unmyelinated fibres, the decrease in the number of silver grains is less than 50% during a 150-day degeneration period. In the isthmic nucleus radioactivity was less intense, when labelled retinal fibres were degenerating in the tectum, as compared to that in normal animals. Radioactivity in the superior colliculus decreased 3 times faster than in the tectum after removal of the labelled eye. We conclude that proline is reutilized for protein synthesis. Unmyelinated fibres degenerate slower than myelinated ones in frogs, and transneuronal transport cannot be enhanced by increased protein breakdown.
在正常大鼠眼内注射氚标记的脯氨酸后长达250天，可在对侧视觉通路中检测到高于本底水平的放射性。银颗粒首先从视网膜消失，最后从上丘消失。在青蛙的视顶盖和峡核中，当标记的视网膜纤维发生华勒氏变性时，需要超过500天才能达到放射性本底水平。摘除标记眼12天后，由有髓纤维形成的顶盖板层中的标记强度明显降低。在无髓纤维层中，在150天的变性期内银颗粒数量减少不到50%。当标记的视网膜纤维在顶盖中变性时，峡核中的放射性强度低于正常动物。摘除标记眼后，上丘中的放射性下降速度比顶盖快3倍。我们得出结论，脯氨酸被重新用于蛋白质合成。青蛙中无髓纤维的变性比有髓纤维慢，并且蛋白质分解增加不能增强跨神经元运输。
