一氧化氮合酶抑制剂抑制吗啡依赖及戒断大鼠脊髓神经元ERK的表达

目的探讨鞘内分别注射非选择性一氧化氮合酶(NOS)抑制剂L-NAME、选择性神经元型一氧化氮合酶(nNOS)抑制剂7-硝基吲哚(7-NI)对吗啡戒断大鼠戒断症状和痛敏行为以及脊髓神经元p-ERK表达的影响。方法采用吗啡依赖及戒断模型,分为正常对照组、依赖组、戒断组、L-NAME组(L-NAME)、7-NI组(7-NI),分别作行为学评分(n=8)、免疫组织化学(n=6)和免疫印迹检测(n=4)。结果实验结果表明,①鞘内注射L-NAME、7-NI可明显减轻吗啡依赖大鼠戒断症状,戒断组戒断症状评分为28.6±4.89,L-NAME组、7-NI组分别为22.1±4.52(P<0.05)、16.2±3.99(P<0.01);戒断组促诱发痛评分(touch evoked agitationscores,TEA score)为13.5±2.55,L-NAME组、7-NI组分别为9.8±3.11(P<0.05)、7.5±2.56(P<0.01)。②鞘内注射L-NAME、7-NI可明显减少胸腰段脊髓背角Fos阳性神经元的数目,L-NAME组、7-NI组分别为293±47、267±52,均低于戒断组(380±71,P<0.05,P<0.01)。③L-NAME、7-NI组p-ERK阳性神经元的数目分别为46.8±11.58、40.5±8.55,均低于戒断组(66.6±11.6,P<0.05,P<0.01),两给药组脊髓p-ERK蛋白的表达也减少。④W estern b lot显示:鞘内注射NOS明显抑制吗啡戒断大鼠脊髓p-ERK蛋白表达增加。结论脊髓水平NO参与吗啡依赖和戒断反应,ERK信号通路可能介导NO的上述作用。

Nitric oxide synthase inhibitors suppression against expression of ERK in spinal cord of morphine dependent and withdrawal rats

Aim This study aimed to explore the effects of intrathecal injection of nitric oxide synthase inhibitors(L-NAME,7-NI) on morphine withdrawal response and the the spinal p-ERK expression.Methods Rats were divided into 5 groups: control group,dependence group,withdrawal group, L-NAME group(L-NAME,it) and 7-NI group(7-NI,it).Morphine withdrawal score,touch evoked agitation scores(TEA scores),immunohistochemical and western-blotting technique were used to evaluate morphine withdrawal response and the expression of Fos and p-ERK in the spinal cord,respectively.Results Intrathecal injection of non-specific NOS inhibitor L-NAME,nNOS inhibitor 7-NI significantly alleviated morphine withdrawal symptoms.Morphine withdrawal scores in the L-NAME(22.1±4.52) and 7-NI groups(16.2±3.99) were significantly lower than that of the withdrawal group(28.6±4.89)(P<0.05,P<0.01);TEA score of the withdrawal group was 13.5±2.55,which was significantly higher than that of the L-NAME(9.8±3.11,P<0.05) and 7-NI groups(7.5±2.56,P<0.01).Fos-like positive neurons(Fos-LI) in the spinal dorsal horn of the withdrawal group were 380±71,which were higher that of the LNAME(293±47,P<0.05) and 7-NI groups(228±49,P<0.01).Phospho-ERK positive neurons in the spinal dorsal horn of the L-NAME and 7-NI groups were 46.8±11.58,40.5±8.55 respectively,which were significantly lower that of the withdrawal group(66.6±11.6,P<0.05,P<0.01).Compared with the withdrawal group,level of p-ERK protein detected by Western blot in spinal cord of the L-NAME and 7-NI groups were significantly lower.Conclusion The spinal NO involves in morphine dependence and withdrawal,and its role may be mediated by ERK signal pathway.