吗啡对谷氨酸和天然辣椒碱引起的大鼠脊髓背角c-Fos蛋白表达的影响

Influence of Intraplantar Morphine on the Spinal c-Fos Expression Induced by Glutamate and Capsaicin

目的探讨足底注射吗啡对谷氨酸和天然辣椒碱所引起的大鼠脊髓背角c-Fos蛋白表达的影响,从而了解阿片和谷氨酸受体在末梢神经痛觉传递中的相互作用。方法72只健康SD雄性大鼠,随机分为12组,每组6只。在大鼠后肢左侧足底分别注射(正常对照组不用药)生理盐水(Saline组)、谷氨酸(Glu组)、天然辣椒碱(Cap组)、吗啡(MOR组)、盐酸纳洛酮(NLX组)、谷氨酸+吗啡(Glu+MOR组)、谷氨酸+盐酸纳洛酮(Glu+NLX组)、谷氨酸+盐酸纳洛酮+吗啡(Glu+NLX+MOR组)、天然辣椒碱+吗啡(Cap+MOR组)、天然辣椒碱+盐酸纳洛酮(Cap+NLX组)、天然辣椒碱+盐酸纳洛酮+吗啡(Cap+NLX+MOR组);注射药物2 h后对脊髓(L4-5)背角出现的c-Fos阳性神经细胞的数量进行观察。结果在脊髓(L4-5)背角浅层的c-Fos阳性神经细胞数,正常对照组为0个;Saline组、MOR组、NLX组分别为(60±5)、(50±14)、(67±22)个,3组比较差异无统计学意义(P>0.05);Glu组、Cap组分别为(268±21)(、489±34)个,与Saline组比较差异有统计学意义(P<0.01);Glu+MOR组为(65±10)个,较Glu组明显减少(P<0.05);Glu+NLX+MOR组为(321±33)个,较Glu+MOR组明显增加(P<0.05);Cap+MOR组为(259±52)个,较Cap组明显减少(P<0.05);Cap+NLX+MOR组为(491±44)个,较Cap+MOR组明显增加(P<0.05)。结论谷氨酸受体参与脊髓背角浅层c-Fos蛋白表达,吗啡激活阿片受体可以导致外源性和内源性谷氨酸所引起的c-Fos阳性蛋白的减少,而盐酸纳洛酮可以拮抗吗啡的这种作用。

Objective To investigate the effects of intraplantar administration on the spinal c-Fos expression induced by intraplantar glutamate and capsaicin and the interaction between glutamate receptors and opioid receptors in pain transmission in peripheral afferents. Methods Seventy-two SD rats were divided at random into twelve groups,and each group consisted of six animals. c-Fos immunohistochemistry was used to detect the expression of c-Fos labeled neurons in L4-5 of spinal cord 2 hours after some drugs injection into the normal control group （no drug used）, saline （Saline group）, glutamate （Glu group）, capsaicin （Cap group）, morphine （ MORgroup）, naloxone （ NLX group）, glutamate＋ morphine （Glut MOR group）, glutamate＋ naloxone （Glu＋NLX group）, glutamate＋ naloxone＋ morphine （Glu ＋ NLX＋ MOR group）, capsaicin＋ morphine （ Cap ＋ MOR group）, capsaicin＋naloxone （Cap ＋ NLX group, ）capsaiein ＋ naloxone ＋ morphine （Cap＋ NLX＋ MOR group）. Results The number of c-Fos labeled neurons in Lt-5 of spinal cord were 0 piece for the normal control group; （60±5）, （50±14） and （67±22） pieces for saline,MOR and NLX group, respectively. There were no statistic significant among the three groups（P〉0.05） ; （268 ± 21） and （489 ± 34） pieces for Glu and Cap group, respectively. There were remarkable statistic significant compared with saline group（P〈0.01）;（65±10） pieces for Glu＋MOR group was lower than Glu group（P〈0.05）;（321±33） pieces for Glu＋NLX＋MOR group was higher than Glu＋MOR group（P〈0.05）;（259±52） pieces for Cap＋MOR group was lower than Cap group（P〈0.05） ;（491±44） pieces for Cap＋NLX＋MOR group was higher than Cap＋ MOR group（P〈0.05）. Conclusion Such results illustrate that glutamate receptors participate in regulate of c-Fos expression in the superficial layer of spinal cord dorsal horn,activation of opioid receptors induce a decrease of the level of e-Fos expression evoked by exogenous and endogenous glutamate,and naloxone could reverse the effect of morphine.