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 / 解剖学报

ABSTRACT

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~H-uridine and 3~H-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~H-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~H-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~H-thymidine incorporation, that the NGF may promote the synthesis of DNA in some neurons of the third day SCG in vitro was also observed.