大鼠尾核内微量注射L-精氨酸对一氧化氮合酶表达的影响

目的探讨大鼠尾核内L-精氨酸（L-Arg）、N^ω硝基-L-精氨酸甲酯（L-NAME）、亚甲基蓝（MB）等对一氧化氮合酶（NOS）表达的影响。方法动物随机分为L-Arg组、L-NAME组、MB组和生理盐水（NS）组，用免疫组织化学结合计算机图像分析的方法观察给药后6、12、24、48和72h尾核内nNOS表达的变化。结果尾核内nNOS神经元散在表达，阳性部位主要在胞浆，神经纤维也有表达。L-Arg组nNOS神经元较正常表达增强（P〈0．05），且随着时间的延长而增强，48h达最高点。MB和L-NAME组nNOS神经元表达较正常减弱（P〈0．05），随时间延长继续减弱，48h达最低点。结论尾核内L-Arg通过NOS生成NO而发挥痛敏作用，L-NAME和MB通过抑制NOS的功能而减少NO的生成产生镇痛作用，NOS是体内合成NO的关键酶。

Effects on the expression of nitric oxide synthase after micro-injectingL-arginine into caudate nucleus of rats

Objective:To discuss the effect on the expression of nitric oxide synthase after micro-injected L-arginine(L-Arg),N(omega)-nitro-L-arginine methyl ester(L-NAME) and methylene blue(MB) into caudate nucleus of rats.Methods:The male Wistar rats were divided into four groups: normal saline group,L-Arg group,L-NAME group and MB group.The method of immunohistochemistry and computer graphic analysis were used to observe the changes of the expression of caudate nucleus nNOS at 6,12,24,48 and 72 hours after administration.Results:The expression of nNOS was divergent in that most of nNOS were in the cytoplasm and small amounts of nNOS were in the nerve fibers.The expression of nNOS was increased by micro-injecting L-Arg into caudate nucleus of rats but it was decreased by micro-injecting L-NAME and MB(P<0.05).Conclusion:L-Arg induces hyperalgesia via NOS in rats' caudate nucleus and L-NAME and MB induces analgesia via inhibiting NOS.NOS is the key enzyme.