家兔若干与下行抑制有关的中枢部位中去甲肾上腺素、5-羟色胺和脑啡肽在针刺镇痛中的变化

应用推挽灌流技术、去甲肾上腺素(NA)放射酶学法和亮-脑啡肽放射免疫法观察不同脑区 NA 和脊髓背角亮-脑啡肽的释放。应用分子筛柱层析分离家兔不同脑区的5-羟色胺(5-HT)和5-羟吲哚乙酸(5-HIAA),并对它们进行荧光微量测定。以此来阐明针刺镇痛时 NA、5-HT 和亮-脑啡肽在下行抑制中的作用。1.家兔电针20 min,痛阈显著提高,此时中脑导水管周围灰质(PAG)和中缝大核(NRM)的 NA 释放显著减少,而 Al 核团和脊髓背角的 NA释放显著增加。2.电针镇痛时,PAG、延脑中缝核区和脊髓的5-HT 和5-HIAA 含量均有显著增加,除 PAG 外,这种增加的出现较 NA 为晚。提示可能在针刺镇痛的下行抑制中,NA 的参予较5-HT 为早。3.针刺镇痛时脊髓背角亮-脑啡肽的释放也明显增加。

CHANGES IN NORADRENAINE,SEROTONIN AND ENKEPHA LIN CONTENTS IN CERTAIN BRAIN STRUCTURES OF RABBIT RELATED TO DESCENDING INHIBITION DURING ACUPUNCTURE ANALGESIA

Push-pull perfusion technique,radioenzymatic assay and radioimmunoassaywere used to observe the changes of noradrenaline(NA)and leucine-enkephalin re-lease from brain nuclei and dorsal horn of spinal cord in rabbits.Serotonin(5-HT)and 5-hydroxyindoleacetic acid(5-HIAA)in the brain and spinal cord were se-parated by chromatography with sephadex G-10 column and determined by spec-trofluorometric assay.1.After 20 minutes of electro-acupuncture,pain threshold was elevated,andat the same time the NA levels in perfusate of periaquaductal grey(PAG)and nucleusraphe magnus(NPM)were markedly decreased during acupuncture analgesia(P<0.01 and P<0.02 respectively),while the NA levels in the perfusate of A1nucleus and dorsal horn of spinal cord were markedly increased(P<0.05).2.The content of 5-HT and 5-HIAA in PAG,bulbar raphe nucleus and spi-nal cord were markedly increased during acupuncture analgesia.With the exceptionof PAG,the appearance of 5-HT and 5-HIAA increase was later than that of NA.It is probable that the process mediated by 5-HT in descending inhibitory actionoccurs later than that by NA.Release of leucine-enkephalin in dorsal horn of spinal cord is increased duringacupuncture analgesia.The results of the above experiments suggest that NA,5-HT and leucine-enke-phalin may play some role in descending inhibitory action of acupuncture analgesia.