Neuronal nitric oxide synthase activation and peroxynitrite formation in ischemic stroke linked to neural damage
Neuronal nitric oxide synthase activation and peroxynitrite formation in ischemic stroke linked to neural damage
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DOI：
10.1523/jneurosci.19-14-05910.1999
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发表时间：
1999-07-15
影响因子：
5.3
通讯作者：
Moskowitz, MA
中科院分区：
文献类型：
--
作者：
Eliasson, MJL;Huang, ZH;Moskowitz, MA
一氧化氮 (NO) 是一种新的细胞间信使，在大脑中自然产生，不会引起明显的毒性。然而，NO 已被认为是细胞死亡中细胞死亡的介质。一种解释是，缺血导致一氧化氮过量产生，使其与超氧化物反应形成强效氧化剂过氧亚硝酸盐。为了解决这个问题，我们对遭受可逆性大脑中动脉闭塞的小鼠进行了瓜氨酸（NO合酶活性标记物）和3-硝基酪氨酸（过氧亚硝酸盐形成标记物）的免疫组织化学检测。我们发现，缺血会引发瓜氨酸免疫反应性显着增强，但在梗塞周围比梗塞组织更是如此。这种增加归因于大量（大约 80%）NO 合酶神经元亚型（nNOS）的激活，该亚型在基础条件下催化失活，表明大脑中生理性 NO 产生的严格调节。相反，3-硝基酪氨酸免疫反应性仅限于梗塞组织，并且不存在于梗塞周围组织中。在已知可防止缺血的 nNOS(Delta/Delta) 小鼠中，未检测到 3-硝基酪氨酸免疫反应性。我们的研究结果提供了与缺血性中风相关的 nNOS 激活的细胞定位，并确定 NO 不太可能是直接的神经毒素，而其转化为过氧亚硝酸盐与细胞死亡相关。
Nitric oxide (NO) is a new intercellular messenger that occurs naturally in the brain without causing overt toxicity. Yet, NO has been implicated as a mediator of cell death in cell death. One explanation is that ischemia causes overproduction of NO, allowing it to react with superoxide to form the potent oxidant peroxynitrite. To address this question, we used immunohistochemistry for citrulline, a marker for NO synthase activity, and 3-nitrotyrosine, a marker for peroxynitrite formation, in mice subjected to reversible middle cerebral artery occlusion. We show that ischemia triggers a marked augmentation in citrulline immunoreactivity but more so in the peri-infarct than the infarcted tissue. This increase is attributable to the activation of a large population (similar to 80%) of the neuronal isoform of NO synthase (nNOS)that is catalytically inactive during basal conditions, indicating a tight regulation of physiological NO production in the brain. In contrast, 3-nitrotyrosine immunoreactivity is restricted to the infarcted tissue and is not present in the peri-infarct tissue. In nNOS(Delta/Delta) mice, known to be protected against ischemia, no 3-nitrotyrosine immunoreactivity is detected. Our findings provide a cellular localization for nNOS activation in association with ischemic stroke and establish that NO is not likely a direct neurotoxin, whereas its conversion to peroxynitrite is associated with cell death.