关于针刺镇痛的原理

许多资料说明脑干中缝核系统在针刺镇痛中起重要作用

中缝核色胺能神经元轴突末梢的神经递质5-羟色胺(5-HT)是针刺镇痛的重要物质基础。中缝核神经元的轴突分布很广

其上行纤维经内侧前脑束(MFB)上达间脑和端脑各部

下行纤维广泛分布于脊髓的灰质

在脑干部分还与兰斑核

巨细胞核等其他网状结构神经核团有广泛联系.以往的工作证Experiments were performed on adult female rats with tail-flick responseas the antinociceptive test.The effects of destruction of ascending 5-HTpathways by mechanical lesions of MFB were similar to these by specificchemical lesions with 5

6-DHT as formerly reported.The 5-HT and 5-HIAAcontents of the telencephalon and diencephalon were lowered markedly aswell as the effect of acupuncture and morphine analgesia.Intraspinal micro-injection of 5

6-DHT lowered selectively the 5-HT content of the spinalcord.It showed that the descending 5-HT pathways were destroyed in certaindegree.Under such condition

the effect of morphine analgesia were lower-red but the effect of acupuncture analgesia remains unchanged.The resultsof these experiments suggest that the ascending 5-HT pathways are moreimportant for acupuncture analgesia than descending 5-HT pathways butboth ascending and descending 5-HT pathways are necessary for morphineanalgesia.