足底伤害性刺激条件下大鼠腰骶髓SP、CGRP、L－ENK样神经成分的变化

CHANGES OF SUBSTANCE P,CALCITONIN GENE-RELATED PEPTIDE,LEUCINE-ENKEPHALIN IN RAT SPINAL CORD RESPONDING TO FORMALIN-INDUCED NOCICEPTIVE STIMULUS

将１０％福尔马林１５０～２００μｌ注入大鼠一侧后肢足底，用注入等量０．９％生理盐水作为对照，分别于刺激后５、１５、３０、６０、９０、１２０ｍｉｎ和１２、２４、４８ｈ取材，进行免疫组化反应（ＡＢＣ法），观察脊髓腰骶段后角浅层及后连合核区的ＳＰ、ＣＧＲＰ、Ｌ－ＥＮＫ样纤维和终末的分布，并随机抽样进行图像分析．结果显示：在福尔马林刺激后，脊髓后角浅层和后连合核区的ＳＰ、ＣＧＲＰ样阳性纤维和终末在５～６０ｍｉｎ明显减少，而到１．５～１２ｈ却呈增加趋势，１２ｈ后逐渐恢复正常．而Ｌ－ＥＮＫ样纤维和终末始终无明显变化．本文结合文献讨论了上述变化与痛与镇痛机制的关系。

Changes of substance P (SP)-, calcitonin gene-related peptide (CGRP)-, leucine-enkephalin (L-ENK)-like immunoreactive (LI) materials on two sides of the lumbosacral dorsal horn and dorsal commissural nucleus were inspected microscopically and quantified with a computer-assisted image processing system in rats with different times (5 min, 15 min, 30 min,60 min, 90 min, 120 min, 12 h, 24 h, 48 h) after injection of 150～200 μl 10% formalin into the left hindpaw subcutanously. The results showed that SP-like immunoreactivity (SP-LI), CGRP-LI in superficial laminae of dorsal horn(DH) and dorsal commissural nucleus(DCN) significantly decreased ipsilaterally from 5 min to 1 h after injection. Then SP-LI and CGRPLI significantly increased ipsilaterally from 1 h to 12 h in these two areas. After 12 h, the levels of SP-LI and CGRP-LI were almost equal between the two sides of DH and DCN. But L-ENK-LI had little change during the process of experiment. It is suggested that the change of these peptides in DH and DCN followed the rule that the quantities of these peptides are decrease (5 min～1 h ), increase (1 h～12 h) and finally tend to be relativity equal (12 h～ ) in response to nociceptive stimulus. This study also discussed the probable machanism of this rule.