Analysis of Intercellular Interaction in a Process of Neurite Growth

已知神经细胞伸长神经突并与靶细胞形成突触结合。在轴突生长的过程中，神经元之间可能会发生细胞间的相互作用。1992年，我们以培养的神经细胞PC_（12）h-R为材料，建立了一种完全排除细胞间相互作用的细胞培养体系，因为在一个培养孔中只培养一个细胞。1993年，通过使用孤细胞系统评估了各种因子（神经营养因子、神经递质、激素、第二信使）的神经突生长起始活性。1994年，我们利用所研制的流动培养系统，分析了影响细胞间相互作用的化学和物理因素。在PC 12 h-R细胞条件培养液上清中，发现了分子量为130- 170 kDa的诱导神经突起生长的化学因子蛋白质，表明交流电（强度>2 μ A）刺激也能诱导神经突起生长。此外，在PC 12 h-R细胞中，分析了神经突起对作用机制与神经细胞不同的NGF或db-cAMP重复作用的反应，这些结果是新的认识，可以通过我们开发的培养系统获得。结果表明，神经突起生长过程中细胞间的相互作用与化学和物理因素有着复杂的关系。

It is known that a neural cell elongates neurites and make a synaptic combination with a target cell. In a process of this neurite growth, some intercellular interaction might be worked between neurons. In order to analyze this intercellular interaction, the present research project was done from 1992 to 1994.In 1992, using the cultured nerve cells PC12h-R,we developed lone cell culture system which excluded the intercellular interaction absolutely because only one cell was cultivated in a culture well. The usefulness of this system for further research work was shown.In 1993, a neurite growth initiating activity of various factors (neurotrophic factors, neurotransmitter, hormone, second messenger) was evaluated by using lone cell system. Moreover, a flow culture system which could change the kind and concentration of working factors continuously and satisfied the lone cell culture condition was developed.In 1994, we analyzed the chemical and physical factors of intercellular interaction by using the developed culture systems. As a chemical factor, some protein, whose molecular weight was 130-170kDa and which induced the neurite growth, was found in the supernatant of the conditioned medium of PC12h-R.It was shown that the stimulation by an alternating current (intensity : >2 muA) also induced the neurite growth. Moreover, in PC12h-R cells, the response of neurites to the repeated actions of NGF or db-cAMP whose action mechanisms were different to neural cells was analyzed.These results were new knowledge and could be obtained by using our developed culture system. It was concluded that both chemical and physical factors were complicatedly related to the intercellular interaction in the process of the neurite growth.