Changes of nerve growth factor synthesis in nonneuronal cells in response to sciatic nerve transection.
Changes of nerve growth factor synthesis in nonneuronal cells in response to sciatic nerve transection.
复制标题
非神经元细胞中神经生长因子合成的变化响应坐骨神经横向。
DOI：
10.1083/jcb.104.6.1623
复制
发表时间：
1987-06
影响因子：
7.8
通讯作者：
Thoenen, H
中科院分区：
文献类型：
--
作者：
Heumann, R;Korsching, S;Bandtlow, C;Thoenen, H
完整的坐骨神经含有神经生长因子（NGF）的水平，其与NGF反应性（交感和感觉）神经元的密集神经支配的外周靶组织的水平相当。在那里，高的NGF水平反映了相应的高mRNAGF水平。在完整的坐骨神经中，mRNAGF水平非常低，因此表明非神经元细胞局部合成的NGF的贡献很小。然而，在横断后，在横断部位近端和远端收集的4 mm节段中测量到mRNAGF增加高达15倍。在横断部位远端，横断后6小时至2周（研究的最长时间段），所有3个4 mm节段的mRNAGF水平均增加。增强局部神经生长因子的合成后，横断是伴随着神经生长因子受体的雪旺细胞（神经生长因子受体通常消失后不久出生）的重新表达。在横断部位的近端，增强的NGF合成被限制在神经残端的最末端，该神经残端充当再生的NGF反应性神经纤维的“替代靶器官”。虽然神经残端中的mRNAGF水平对应于密集神经支配的外周器官的mRNAGF水平，但体积太小，无法完全替代来自外周的缺乏的供应。这反映在以下事实中：在横切的坐骨神经的更近端部分中，其中mRNAGF保持不变，NGF水平仅达到对照值的40%。原位杂交实验表明，横切后，所有非神经元细胞表达mRNAGF，而不仅仅是那些神经纤维鞘的神经生长因子反应神经元。
The intact sciatic nerve contains levels of nerve growth factor (NGF) that are comparable to those of densely innervated peripheral target tissues of NGF-responsive (sympathetic and sensory) neurons. There, the high NGF levels are reflected by correspondingly high mRNANGF levels. In the intact sciatic nerve, mRNANGF levels were very low, thus indicating that the contribution of locally synthesized NGF by nonneuronal cells is small. However, after transection an increase of up to 15-fold in mRNANGF was measured in 4-mm segments collected both proximally and distally to the transection site. Distally to the transection site, augmented mRNANGF levels occurred in all three 4-mm segments from 6 h to 2 wk after transection, the longest time period investigated. The augmented local NGF synthesis after transection was accompanied by a reexpression of NGF receptors by Schwann cells (NGF receptors normally disappear shortly after birth). Proximal to the transection site, the augmented NGF synthesis was restricted to the very end of the nerve stump that acts as a "substitute target organ" for the regenerating NGF-responsive nerve fibers. While the mRNANGF levels in the nerve stump correspond to those of a densely innervated peripheral organ, the volume is too small to fully replace the lacking supply from the periphery. This is reflected by the fact that in the more proximal part of the transected sciatic nerve, where mRNANGF remained unchanged, the NGF levels reached only 40% of control values. In situ hybridization experiments demonstrated that after transection all nonneuronal cells express mRNANGF and not only those ensheathing the nerve fibers of NGF-responsive neurons.