Diazoxide induces delayed pre-conditioning in cultured rat cortical neurons
Diazoxide induces delayed pre-conditioning in cultured rat cortical neurons
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DOI：
10.1046/j.1471-4159.2003.02072.x
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发表时间：
2003-11-01
影响因子：
4.7
通讯作者：
Busija, DW
中科院分区：
文献类型：
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作者：
Kis, B;Rajapakse, NC;Busija, DW
我们研究了二氮嗪对原代培养的大鼠皮层神经元在缺氧-葡萄糖剥夺(OGD)条件下存活的影响。二氮嗪预处理可诱导延迟预适应，并几乎完全减轻OGD诱导的神经元死亡。二氮嗪抑制琥珀酸脱氢酶，诱导线粒体去极化、自由基产生和蛋白激酶C活化。线粒体ATP敏感性钾通道阻滞剂5-羟基癸酸可阻断二氮嗪的保护作用，而非选择性K-ATP通道阻滞剂格列本脲则不能。非选择性K-ATP通道开放剂尼可地尔和克罗卡林不能提高细胞存活率。超氧化物歧化酶模拟物M40401或蛋白激酶C抑制剂白屈菜红碱可阻止二氮卓的神经保护作用。二氮嗪不增加还原型谷胱甘肽和锰超氧化物歧化酶的水平，但我们发现OGD后二氮卓预适应神经元的还原型谷胱甘肽水平显着升高。在预适应神经元中，谷氨酸刺激会减少自由基的产生。琥珀酸脱氢酶抑制剂3-硝基丙酸也诱导了神经元的预适应和自由基的产生。在这里，我们提供了首次证据表明，二氮卓通过OGD后急性产生超氧阴离子和蛋白激酶的激活以及随后的氧化应激减弱而诱导神经元延迟预适应。二氮嗪对琥珀酸脱氢酶的抑制作用比线粒体ATP敏感性钾通道的开放更有可能参与这种神经保护作用。
We investigated the effect of diazoxide on neuronal survival in primary cultures of rat cortical neurons against oxygen-glucose deprivation (OGD). Diazoxide pre-treatment induced delayed pre-conditioning and almost entirely attenuated the OGD-induced neuronal death. Diazoxide inhibited succinate dehydrogenase and induced mitochondrial depolarization, free radical production and protein kinase C activation. The putative mitochondrial ATP-sensitive potassium channel blocker 5-hydroxydecanoate abolished the protective effect of diazoxide while the non-selective K-ATP channel blocker glibenclamide did not. The non-selective K-ATP channel openers nicorandil and cromakalim did not improve viability. Superoxide dismutase mimetic, M40401, or protein kinase C inhibitor, chelerythrine, prevented the neuroprotective effect of diazoxide. Diazoxide did not increase reduced glutathione and manganese-superoxide dismutase levels but we found significantly higher reduced glutathione levels in diazoxide-pre-conditioned neurons after OGD. In pre-conditioned neurons free radical production was reduced upon glutamate stimulation. The succinate dehydrogenase inhibitor 3-nitropropionic acid also induced pre-conditioning and free radical production in neurons. Here, we provide the first evidence that diazoxide induces delayed pre-conditioning in neurons via acute generation of superoxide anion and activation of protein kinases and subsequent attenuation of oxidant stress following OGD. The succinate dehydrogenase-inhibiting effect of diazoxide is more likely to be involved in this neuroprotection than the opening of mitochondrial ATP-sensitive potassium channels.