Characterization of reduced and oxidized dopamine and 3,4-dihydrophenylacetic acid, on brain mitochondrial electron transport chain activities
Characterization of reduced and oxidized dopamine and 3,4-dihydrophenylacetic acid, on brain mitochondrial electron transport chain activities
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DOI：
10.1016/j.bbabio.2011.03.013
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发表时间：
2011-07-01
影响因子：
4.3
通讯作者：
Zeevalk, Gail D.
中科院分区：
文献类型：
--
作者：
Gautam, Alpa H.;Zeevalk, Gail D.
多巴胺（DA）稳态的丧失可能是帕金森病（PD）细胞损伤的一个促成因素。然而，过去显示DA对线粒体功能的有害影响的研究一直不一致，这引发了关于线粒体作为DA下游靶点的问题。还原或氧化、暴露时间和主要代谢物如3，4-二氢苯乙酸（DOPAC）的作用可能导致不同的结果。本研究使用分离的，裂解的大鼠脑线粒体的特点的影响，氧化或还原DA和DOPAC的复杂活动的电子传递链（ETC）。对于所有实验，监测DA和DOPAC的还原或氧化catachol的暴露时间和定量。减少DA和DOPAC与或不与30分钟的预孵育没有影响NADH氧化酶的活性，监测活动的复合物I，III和IV。复合物II的活性被还原DA（>= 500 μ M）抑制，但不被还原DOPAC和SOD表明活性氧参与显着衰减。相反，完全氧化的DA和DOPAC剂量依赖性地抑制NADH氧化酶，复合物I和复合物III的活性，IC 50在50-200 μ M的范围内。当儿茶酚被完全氧化时，不需要预孵育来抑制。氧化DA抑制复合物I只有当暴露发生在刺激的电子流，这表明共价结合的醌类蛋白质内的活性位点的复杂。在完整的，耦合良好的线粒体，extramitoditrial DA显示访问线粒体基质中的剂量，时间和能量依赖性的方式。研究结果表明，许多报告的不一致的影响DA和DOPAC ETC功能可以归因于氧化状态的儿茶酚在曝光的时间。此外，这些发现为DA提供了可能的下游靶点，可能有助于PD中多巴胺能神经元的脆弱性。(C)2011 Elsevier B. V.保留所有权利。
Loss of dopamine (DA) homeostasis may be a contributing factor to cell damage in Parkinson's disease (PD). Past studies showing deleterious effects of DA on mitochondrial function, however, have been inconsistent raising questions about mitochondria as a downstream target for DA. Issues such as the dopamine species i.e., reduced or oxidized, time of exposure and the effect of major metabolites such as 3,4-dihydrophenylacetic acid (DOPAC) may contribute to the disparate findings. The present study used isolated, lysed rat brain mitochondria to characterize the effects of oxidized or reduced DA and DOPAC on complex activities of the electron transport chain (ETC). Time of exposure and quantitation of reduced or oxidized catachols for DA and DOPAC were monitored for all experiments. Reduced DA and DOPAC with or without a 30 min preincubation had no affect on NADH oxidase activity which monitors the activities of complexes I, III and IV. Complex II activity was inhibited by reduced DA (>= 500 mu M), but not by reduced DOPAC and was significantly attenuated by SOD suggesting reactive oxygen species involvement. In contrast, fully oxidized DA and DOPAC dose dependently inhibited NADH oxidase, complex I and complex III activities with IC50s in the 50-200 mu M range. No preincubation was required for inhibition with the catechols when they were fully oxidized. Oxidized DA inhibited complex I only when exposure occurred during stimulated electron flow, suggesting covalent binding of quinones to proteins within active sites of the complex. In intact, well coupled mitochondria, extramitochondrial DA was shown to access the mitochondrial matrix in a dose, time and energy-dependent fashion. The findings suggest that many of the reported inconsistencies with regards to the effects of DA and DOPAC on ETC function can be attributed to the oxidized state of the catechol at the time of exposure. In addition, the findings provide possible downstream targets for DA that could contribute to the vulnerability of dopaminergic neurons in PD. (C) 2011 Elsevier B.V. All rights reserved.