吗啡耐受增加福尔马林致痛大鼠脊髓Fos和NADPH-d阳性神经元的表达

Increased expression of formalin induced Fos and NADPH d positive neurons in the spinal cord of morphine tolerant rats

运用Fos免疫组织化学、NADPH d组织化学及Fos/NADPH d双标技术 ,研究了吗啡耐受对福尔马林致痛大鼠脊髓Fos、NADPH d阳性及Fos/NADPH d双标神经元表达的影响。结果观察到 :在非吗啡耐受大鼠 ,福尔马林诱发的Fos likeimmunoreactivity (Fos LI)主要分布在同侧脊髓背角浅层和颈部 ,急性静注吗啡可减少Fos LI表达 ;长时间应用吗啡导致福尔马林诱发的Fos LI明显增加 ,且在同侧脊髓全层和对侧脊髓均有分布 ,急性静注吗啡不能抑制Fos LI表达。吗啡耐受增加福尔马林致痛大鼠脊髓背角浅层NADPH d阳性神经元、纤维及终末的表达。吗啡耐受大鼠福尔马林诱发的Fos/NADPH d双标神经元明显增多 ,在同侧脊髓全层和对侧脊髓浅层均有分布。上述结果提示 ,NO参与了吗啡耐受导致的脊髓背角神经元敏感化。

Fos immunocytochemistry, NADPH d histochemistry and Fos/NADPH d double labeling method were used to study the changes in formalin induced Fos, NADPH d positive and Fos/NADPH d double labeled neurons in the spinal cord of morphine tolerant rats. Formalin induced Fos like immunoreactivity (Fos LI) was located in the superficial laminae and neck of ipsilateral spinal cord. Acute administration of morphine de^creased the expression of Fos LI in non tolerant rats, while the expression of Fos LI was significantly increased in morphine tolerant rats. Fos LI was distributed not only in the whole laminae of the ipsilateral spinal cord but also in the contralateral spinal cord. Acute administration of morphine was ineffective in de^crea^sing the expression of Fos LI in morphine tolerant rats. Morphine tolerance increased the expression of formalin induced NADPH d positive neurons in the superficial laminae of spinal dorsal horn. A few formalin induced Fos/NADPH d double labeled neurons were detected in the superficial laminae of spinal dorsal horn of non tolerant rats. In morphine tolerant rats, on the other hand, formalin induced Fos/NADPH d double labeled neurons were increased and distributed in the whole laminae of the ipsilateral spinal cord and the contralateral superficial spinal cord. It is suggested that NO is involved in the increase of formalin induced Fos LI in the spinal cord of morphine tolerant rats and may play an important role in the development of morphine tolerance.