Effect of insulin like-growth factor on development and survival of cholinergic neurons

我们研究了胰岛素样生长因子II （IGFII）对小鼠胚胎第15天脑中隔原代培养物的影响。在间隔培养物中添加IGFII，总胆碱乙酰转移酶（ChAT）活性呈剂量依赖性增强。IGFII对ChAT活性的影响被抗IGFII/M-6-P受体抗体完全阻断，而单独使用抗血清对ChAT活性没有影响。双标记免疫组织化学研究显示，大多数chat阳性神经元表达IGFII/M-6-P受体免疫反应性。这些结果表明，IGFII的营养作用是通过IGFII/M-6-P受体在间隔胆碱能神经元中的直接作用产生的。我们还通过逆转录和聚合酶链反应以及使用IL-3依赖细胞系的生物测定，检测了白细胞介素-3 (IL-3) mRNA和IL-3蛋白在小鼠原代培养的神经元和胶质细胞中的表达和产生。IL-3 mRNA主要在海马神经元中表达，而在胶质细胞中不表达，而在间隔和海马神经元培养中检测到少量但确定的生物活性IL-3的产生。因此，内源性IL-3可能由某些神经元原位产生。

We investigated the effect of insulin-like growth factors II (IGFII) on septal primary cultures from mouse embryonic day 15 brains. The addition of IGFII to septal cultures enhanced total choline acetyltaransferase (ChAT) activity in a dose-dependent manner. The effect of IGFII on ChAT activity was completely blocked by anti-IGFII/M-6-P receptor antibodies, whereas the antisera alone had no effect on the enzyme activity. Double-labeled immunohistochemical studies revealed that most ChAT-positive neurons expressed IGFII/M-6-P receptor immunoreactivity. These results indicate that the trophic effect of IGFII results from the direct action of this molecule through the IGFII/M-6-P receptor in septal cholinergic neurons. We also examined expression and production of interleukin-3 (IL-3) mRNA and IL-3protein in mouse primary cultured neurons and glia by the reverse transcription and polymerase chain reaction and bioassay using an IL-3-dependent cell line. IL-3 mRNA was demonstrated mainly in hippocampal neurons but not in glia, while a small but definite production of bioactive IL-3 was detected in septal and hippocampal neuronal cultures. Thus, endogenous IL-3 might be produced by certain neurons in situ.