Objectives : To observe the changes in the expression of neurotransmitters NO and enzymes that create NO, such as nNOS, iNOS and eNOS, upon the needle insertion on river point, one of the five transport points of three yang meridians on the forefoot. Methods : Based on rats, needle was inserted on both sides of LI5, SI5 and TE6, which are river points of three yang meridians on the forefoot, and were retained for five minutes. After the retention, blood was drawn via cardiac puncture and tissues from each point around meridian vessels were extracted to be examined on the changes of the expression of NO, as well as of nNOS, iNOS and eNOS. Results : In terms of the effect on NO creation in tissues, none of the experimental groups showed any significant change compared to the Normal group. In terms of the effect on expression of nNOS within tissues, LI5 and SI5 showed significant increase based on the results of immunohistochemistry. In iNOS within tissues, LI5 and SI5 showed significant increase based on the results of immunohistochemistry. In eNOS within tissues, SI5 showed significant increase based on the results of immunohistochemistry. Conclusions : The effect on the function of NO, nNOS, iNOS and eNOS of needle insertion on the river points of three yang meridians on the forefoot could be observed, and based on this study, it is considered that the effect of needle stimulation on the changes of nervous system could be found out through additional research.