NOS抑制剂L－NAME的镇痛、致痛和致瘫作用

鞘内注射（ｉｔ）ＮＯＳ抑制剂Ｌ－ＮＡＭＥ０．１２５～４μｍｏｌ可剂量依赖性抑制大鼠足底注射Ｆｏｒｍａｌｉｎ引起的癌症反应，并有７／３１大鼠出现迟发性一过性双后肢瘫痪。ｉｔＬＮＡＭＥ５μｍｏｌ对正常大鼠无明显影响，但１０μｍｏｌ和２０μｍｏｌ均引起明显的痛敏及截瘫．ｉｔ另一ＮＯＳ抑制剂氨基胍０．２～１．０μｍｏｌ也显著抑制Ｆｏｒｍａｌｉｎ痛定反应，１．２５～７．０μｍｏｌ则引起正常大鼠剂量依赖性痛敏行为，但对后肢运动功能无影响。结果表明脊髓水平ＮＯ在痛觉传递与调制中起重要作用，过度抑制ＮＯ的产生可引起痛觉敏化和瘫痪。

NOS inhibitor L-NAME produces analgesia,hyperalgesia and paralysis in rats

Intrathecal administration(it) of NGNitro-L-Arginine Methyl Ester(L-NAME) 0.125 to 4μmol produced a dose-dependant inhibition of the formalin-induced nociceptive behavior(weighted score) in rats,some of which(7/31),however,showed a delayed transient hindlimb paralysis.In normal rats,it L-NAME 5μmol did not produce any behavioral abnormalities but higher dose of it LNAME(both 10μmol and 20μmol) induced significant paraplegia and hyperalgesia.Another nitric oxide synthase inhibitor,aminoguanidine,exhibited significant antinociception in the formalin test at dose of it 0.2 to 1μmol and produced a dose-dependant byperalgesia in normal rats at higher dose of 1.25 to 7umol but did not induce any motor dysfunction.These results suggested that nitric oxide plays a dual role in spinal nociceptive modulation and L-NAME produces spinal cord injury.