吗啡对小鼠纹状体细胞外尿嘧啶释放的影响及机制初探

目的:研究吗啡对小鼠纹状体细胞外尿嘧啶释放的影响并探讨相关机制。方法:采用脑内微透析技术结合高效液相紫外检测器检测尿嘧啶含量,紫外分光光度法检测纹状体总RNA含量。结果:与空白对照组相比,吗啡(10,20mg.kg-1,ip)可显著降低小鼠纹状体尿嘧啶含量且呈现剂量依赖性;盐酸纳洛酮(4mg.kg-1,ip)自身对小鼠纹状体尿嘧啶的释放无影响,却可以显著回升尿嘧啶含量至基础水平。吗啡(10,20mg.kg-1,ip)对小鼠纹状体细胞内RNA含量呈下调作用,与对尿嘧啶含量的下调结果一致,呈现剂量依赖性;盐酸纳洛酮(4mg.kg-1,ip)对小鼠纹状体总RNA含量无明显影响但能拮抗吗啡对总RNA含量的下调作用。结论:吗啡引起小鼠纹状体尿嘧啶释放降低的作用可能与μ受体相关且与细胞内总RNA的含量变化存在相关性。

Effect of morphine on brain uracil release in mice striatum and its preliminary mechanisms

Objective：To investigate the effects of morphine on extracellular uracil release in mice striatum and its preliminary mechanisms.Methods：In vivo microdialysis coupled to high performance liquid chromatography（HPLC） was employed to detect the extracellular contents of uracil in mice striatum,and total RNA level was determined by ultraviolet spectrophotometry.Results：Morphine（10,20 mg·kg-1,ip） could decrease uracil level significantly and it was in a dose-dependent manner.Meanwhile,naloxone（4 mg·kg-1,ip）,antagonists of μ-opioid receptor,had no effect on uracil release in mice striatum.However,it could increase uracil to the normal level.Morphine（10,20 mg·kg-1,ip） decreased the total RNA level in mice striatum and it was in a dose-dependent manner.Naloxone（4 mg·kg-1,ip） had no effect on total RNA level in mice striatum,but it could antagonise the down-regulation of morphine on RNA level.Conclusion：The decrease of uracil induced by morphine may be related to μ-opioid receptors and total RNA level.