Karwacka H, Sitkiewicz D, Skonieczna M, Bicz W, Dymecki J
Exp Pathol (Jena). 1980;18(3):181-92. doi: 10.1016/s0014-4908(80)80019-6.
The effect of chronic ethanol intoxication on oxidative phosphorylation in the rat brain mitochondrial fraction was examined. Moreover, electron microscopy was used to verify the quantitative composition of the fraction and for examination of ultrastructural changes in the mitochondria. The experiments were carried out with 60 rats receiving, beside the normal diet, ethyl alcohol according to a modified RATCLIFFE model. In isolated rat brain mitochondria the NAD-dependent oxidation of substrates (glutamate + malate) was decreased. The phosphorylation index ADP/0 and the respiratory control ratio (RCR) in rat brain mitochondria from ethanol-treated rats were unchanged in the presence of both succinate and glutamate + malate. Chronic ethanol feeding did not induce any changes of succinate dehydrogenase and cytochrome oxidase activities in solubilised mitochondria fractions of rat brain. Electron microscopy studies revealed that mitochondria from control animals retained their outer and inner membranes, whereas those from rats given ethanol were almost always swollen and some were disrupted. In mitochondrial fractions isolated from ethanol-intoxicated rats an increase was observed of contaminating elements i.e. axons and synaptosomes of various sizes. It should be stressed that the mitochondria located inside synaptosomes and axons were unchanged. The composition of the fractions was quantitatively evaluated and confirmed the diminution of "free" mitochondria in the experimental fractions in favour of "bound" mitochondria which mainly occurred in the synaptosomes with preserved metabolic activity. On the basis of electron microscopy studies it could be suggested that ethanol intoxication causes the damage of some mitochondria, which become more sensitive to mechanical destruction during isolation procedure, and they do not sediment together with the fraction of normal ones. The absence of "free" mitochondria in pellets explains the spurious lack of disturbances in the energy metabolism of brain mitochondria after chronic ethanol intoxication.
研究了慢性乙醇中毒对大鼠脑线粒体部分氧化磷酸化的影响。此外，还利用电子显微镜来验证该部分的定量组成，并检查线粒体的超微结构变化。实验使用了60只大鼠，除正常饮食外，根据改良的拉特克利夫模型给予乙醇。在分离的大鼠脑线粒体中，底物（谷氨酸+苹果酸）的NAD依赖性氧化减少。在琥珀酸和谷氨酸+苹果酸存在的情况下，乙醇处理大鼠的脑线粒体中的磷酸化指数ADP/O和呼吸控制率（RCR）未发生变化。长期给予乙醇并未诱导大鼠脑可溶性线粒体部分中琥珀酸脱氢酶和细胞色素氧化酶活性的任何改变。电子显微镜研究表明，对照动物的线粒体保留了其外膜和内膜，而给予乙醇的大鼠的线粒体几乎总是肿胀的，有些甚至破裂。在从乙醇中毒大鼠分离的线粒体部分中，观察到污染元素即各种大小的轴突和突触体增加。应该强调的是，位于突触体和轴突内的线粒体未发生变化。对这些部分的组成进行了定量评估，证实了实验部分中“游离”线粒体的减少，有利于“结合”线粒体，后者主要存在于具有保留代谢活性的突触体中。基于电子显微镜研究，可以认为乙醇中毒会导致一些线粒体受损，这些线粒体在分离过程中对机械破坏更敏感，并且它们不会与正常线粒体部分一起沉淀。沉淀中没有“游离”线粒体解释了慢性乙醇中毒后脑线粒体能量代谢中看似没有干扰的原因。
