Nerve growth factor regulates synaptophysin expression in developing trigeminal ganglion neurons in vitro.

Nerve growth factor regulates synaptophysin expression in developing trigeminal ganglion neurons in vitro.

The role of neuronal growth factors in synaptic maturation of sensory neurons, including trigeminal ganglion (TG) neurons, remains poorly understood. Here, we show that nerve growth factor (NGF) regulates the intracellular distribution of the synaptic vesicle protein synaptophysin (Syp) in newborn rat TG neurons in vitro. While reducing the number of Syp-positive cell bodies, NGF dramatically increases Syp immunoreactivity in both proximal and distal segments of the neurite. Intriguingly, the increase in Syp immunoreactivity occurs only in neuron-enriched cultures, in which the number of non-neuronal cells is significantly reduced. Together, our data indicate that NGF is a candidate molecule involved in early postnatal maturation of TG neurons, including control of presynaptic assembly, and thereby formation of synaptic connections.

神经生长因子在感觉神经元（包括三叉神经节神经元）突触成熟中的作用仍知之甚少。在此，我们表明神经生长因子（NGF）在体外调节新生大鼠三叉神经节神经元中突触囊泡蛋白突触素（Syp）的细胞内分布。在减少Syp阳性细胞体数量的同时，NGF显著增加神经突近端和远端部分的Syp免疫反应性。有趣的是，Syp免疫反应性的增加仅发生在富含神经元的培养物中，其中非神经元细胞的数量显著减少。总之，我们的数据表明NGF是参与三叉神经节神经元出生后早期成熟的候选分子，包括对突触前组装的控制，从而对突触连接的形成起作用。