Analysis of Intercellular Interaction in a Process of Neurite Growth

众所周知，神经细胞延长神经突并与靶细胞形成突触结合。在神经突生长的过程中，神经元之间可能存在细胞间的相互作用。为了分析这种细胞间的相互作用，本研究项目是从1992年到1994年进行的。1992年，我们利用培养的神经细胞PC12h-R，开发了完全排除细胞间相互作用的单细胞培养系统，因为一个培养孔中只培养一个细胞。表明了该系统对进一步研究工作的有用性。1993年，用单细胞系统评价了多种因子（神经营养因子、神经递质、激素、第二信使）对神经突生长启动活性的影响。此外，还开发了一种能连续改变工作因子种类和浓度，满足单细胞培养条件的流动培养系统。1994年，我们利用已开发的培养系统分析了细胞间相互作用的化学和物理因素。作为化学因子，在PC12h-R条件培养基上清液中发现了一些分子量为130-170kDa的诱导神经突生长的蛋白。结果表明，交变电流（强度：bbb20 μ a）刺激也能诱导神经突生长。此外，在PC12h-R细胞中，我们分析了不同神经细胞作用机制的NGF或db-cAMP对神经突的反应。这些结果是新的知识，可以通过我们开发的培养系统获得。综上所述，在神经突生长过程中，化学和物理因素都与细胞间相互作用有复杂的关系。

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.