Liu Hai-lin, Qian Yan-ning
Department of Anesthesiology, 1st Affiliated Hospital of Nanjing Medical University, Nanjing, China.
Zhongguo Ying Yong Sheng Li Xue Za Zhi. 2012 May;28(3):249-53.
To explore the effects of intrathecal injection of neuronal nitric oxide synthase (nNOS) inhibitors 7-Nitroindazole (7-Ni) and inducible nitric oxide synthase(iNOS) inhibitors aminoguanidine (AG) on the behavioral changes of morphine-induced dependent and withdrawal rats; the expression of Fos, nNOS and iNOS in spinal cord.
To set up morphine dependence model, rats were subcutaneously injected with morphine (twice a day, for 5 d). The dose of morphine was 10 mg/kg in the first day and was increased by 10 mg/ kg every day. On day 6, 4 h after the injection of morphine (50 mg/kg), morphine withdrawal syndrome was precipitated by an injection of naloxone (4 mg/kg ip). 7-Ni, an nNOS inhibitor or iNOS inhibitors AG were intrathecally injected 30 min before the administration of naloxone respectively. The scores of morphine withdrawal symptom and morphine withdrawal-induced allodynia were observed. One hour after naloxone-precipitated withdrawal, Fos protein expression was assessed by immunohistochemical analysis and Western blot was used to detect the expression of nNOS and iNOS in the rat spinal cord.
Intrathecal administration of nNOS inhibitor 7-Ni and iNOS inhibitors AG decreased the scores of morphine withdrawal, attenuated morphine withdrawal-induced allodynia and also inhibited the increase of Fos protein expression in the spinal cord of morphine withdrawal rats. nNOS and iNOS positive neurons in dorsal horn in nNOS group and iNOS group were significantly lower than that in withdrawal group. Compared with withdrawal group, level of nNOS and iNOS protein in spinal cord in nNOS group and iNOS group were significantly lower.
It is suggested that nNOS and iNOS in the spinal cord may contribute to naloxone-precipitated withdrawal in rats and may play different roles in the above-mentioned effect.
探讨鞘内注射神经元型一氧化氮合酶（nNOS）抑制剂7-硝基吲唑（7-Ni）和诱导型一氧化氮合酶（iNOS）抑制剂氨基胍（AG）对吗啡诱导的依赖和戒断大鼠行为变化以及脊髓中Fos、nNOS和iNOS表达的影响。
建立吗啡依赖模型，大鼠皮下注射吗啡（每天2次，共5天）。吗啡剂量第1天为10mg/kg，此后每天增加10mg/kg。第6天，注射吗啡（50mg/kg）4小时后，腹腔注射纳洛酮（4mg/kg）诱发吗啡戒断综合征。分别在给予纳洛酮前30分钟鞘内注射nNOS抑制剂7-Ni或iNOS抑制剂AG。观察吗啡戒断症状评分和吗啡戒断诱导的痛觉过敏。纳洛酮诱发戒断1小时后，通过免疫组织化学分析评估Fos蛋白表达，并用蛋白质印迹法检测大鼠脊髓中nNOS和iNOS的表达。
鞘内注射nNOS抑制剂7-Ni和iNOS抑制剂AG可降低吗啡戒断评分，减轻吗啡戒断诱导的痛觉过敏，并抑制吗啡戒断大鼠脊髓中Fos蛋白表达的增加。nNOS组和iNOS组背角nNOS和iNOS阳性神经元明显低于戒断组。与戒断组相比，nNOS组和iNOS组脊髓中nNOS和iNOS蛋白水平明显降低。
提示脊髓中的nNOS和iNOS可能参与大鼠纳洛酮诱发的戒断反应，并在上述效应中可能发挥不同作用。
