神经生长因子对体外培养的大鼠颈上节神经突起生长及RNA和DNA合成的作用的放射自显影研究

EFFECTS OF NERVE GROWTH FACTOR ON NEURITE OUTGROWTH AND ON SYNTHESIS OF RNA AND DNA IN RAT SUPERIOR CERVICAL GANGLIA IN VITRO:AN AUTORADIOGRAPHIC STUDY

神经生长因子(NGF)可促进靶神经节神经突起生长晕的生长。本文应用^(3)H-尿嘧啶核苷和^(3)H-胸腺嘧啶核苷放射自显影术,进一步研究该作用与神经元合成RNA和DNA的关系。用新生大鼠颈上节,按Maximow双盖片法进行培养。培养物分NGF组(培养液内添加NGF粗制剂)和对照组(不用NGF)。NGF组培养物被^(3)H-尿嘧啶核苷标记的神经元百分率及标记颗粒水平,均高于对照组,而且每当培养物神经突起生长晕生长速度即将出现高峰时,神经元^(3)H-尿嘧啶核苷标记颗粒水平都明显地增高,说明NGF可促进颈上节神经元的RNA合成,后者与神经突起的迅速生长有一定相互关系。在^(3)H-胸腺嘧啶核苷标记培养物神经元的实验中,观察到NGF可促进培养第3天的颈上节少量的神经元合成DNA。

Nerve growth factor(NGF)can promote the outgrowth of neurites of the target ganglia.In order to further explore the relationship between this effect and the synthesis of RNA and DNA in the neurons,an autoradiography of 3-uridine and 3-thymidine was used.Superior cervical ganglia(SCG)from newborn rats were cultivated by Maximow’s double coverslip method.All cultures were divided to one group of cultures a crude preparation of NGF was added to the medium and another group without NGF served as control.Before tissue culture was stopped,the.covership cultures were transferred to thelabeling-medium and incubated,and then they were fixed,and cut into serial sections and subjected to autoradiographie processes.The results show that the percentage and the level of grains of neurons labeled by 3-uridine in the NGF group are higher than that of control.Moreover,before the growth rate of neurites reaches a peak,the level of grains of neurons labeled by 3-uridine in the NGF group is obviously increased.The evidence suggests that NGF can promote the synthesis of RNA in neurons of SCG,which has a direct bearing on the quick outgrowth of neurites.In the experiments with 3-thymidine incorporation,that the NGF may promote the synthesis of DNA in some neurons of the third day SCG in vitro was also observed.