针刺疗法是我国传统医学的宝贵遗产之一

有着几千年的医疗实践经验。针刺能够镇痛

引起了人们广泛的兴趣。自从1973年Pert和Snyder发现脑内存在有阿片受体后

把对镇痛本质的研究大大向前推进了一步。在研究阿片受体的基础上

进而寻找能和阿片受体结合的内源性配基

1975年Hughes等首先从猪脑中分离得到两个阿片样五肽——亮氨酸脑啡肽和甲硫氨酸脑啡肽。其后

又相继发现了β-内啡肽、α-内啡肽、γ-内啡肽、δ-Naga peptide is a new opioid tetrapeptide

which was found in human brain. We succesfully isolated it from the rabbit PAG. The perfusion technique was used for collecting sample of analysis. The perfusate was purified through a small column of Amberlite XAD- 2. The eluates were dried under vacuum. It was dansylated and chromatog- raphed on polyamide layer sheet. The fluorescent spot of DNS-peptide was eluted by methanol. Amino acids composition and sequence of the purified peptide were analysed by dansyl procedure and mass spectrome- try. It is shown that the structure of this peptide isolated from rabbit brain is Asn-Ala-Gly-Ala

which is coiacident with Naga peptide from human brain. The relationship between the Naga peptide and electroacupuncture analgesia was studied by the method of ultramicroanalysis and the technique of perfusion. The quantity of Naga peptide was estimated by scanning developed fluorescent spot on polyamide layer sheet on Hitachi MPF-4 fluorescent photometer. It was increased markedly about 4.80±0.98 nmole per milliter of perfusate (P<0.002

n=10)and the pain threshold of the animal was increased about 2.8 fold of the basal pain threshold. These results show that the Naga peptide exists not only in the human brain but also in the rabbit brain and it is related to acupuncture analgesia.