Camici P, Ursini F, Galiazzo F, Bellitto L, Pelosi G, Marzilli M, L'Abbate A, Barsacchi R
Basic Res Cardiol. 1984 Jul-Aug;79(4):454-60. doi: 10.1007/BF01908146.
Mitochondria were prepared from the subendocardial and subepicardial layers of the canine left ventricle. The oxidation rates of palmitate, palmitoyl carnitine and pyruvate of the mitochondria obtained from the two cardiac layers were measured. The cytochrome content and the specific activities of different beta oxidation and Krebs cycle enzymes were also measured in the two mitochondrial populations. Mitochondria isolated from the ENDO layer showed significantly higher oxidation rates than mitochondria from the EPI layer for all the three substrates. No statistically significant differences in cytochrome c+c1 and a+a3 content were found in mitochondria isolated from the two regions. No significant transmural differences were found in fatty acyl CoA, L-3-hydroxy fatty acyl CoA, succinic and malic dehydrogenase specific activities, whilst isocitric dehydrogenase (NADP) specific activity was significantly higher in mitochondria isolated from the inner layer. In conclusion, the mitochondria isolated from the inner left ventricular layer of the canine heart show a higher oxidative capacity than subepicardial mitochondria. This difference could partly be explained by the higher specific activity of isocitric dehydrogenase in this layer. These properties of subendocardial mitochondria could represent a metabolic support for the greater contractile performance of this layer.
线粒体取自犬左心室的心内膜下层和心外膜下层。测量了从这两个心脏层获得的线粒体中棕榈酸、棕榈酰肉碱和丙酮酸的氧化速率。还测量了这两个线粒体群体中的细胞色素含量以及不同β氧化和三羧酸循环酶的比活性。从心内膜层分离的线粒体对所有三种底物的氧化速率均显著高于从心外膜层分离的线粒体。在从这两个区域分离的线粒体中，未发现细胞色素c + c1和a + a3含量存在统计学显著差异。在脂肪酰辅酶A、L-3-羟基脂肪酰辅酶A、琥珀酸和苹果酸脱氢酶比活性方面未发现显著的透壁差异，而从内层分离的线粒体中异柠檬酸脱氢酶（NADP）的比活性显著更高。总之，从犬心脏左心室内层分离的线粒体比心外膜线粒体具有更高的氧化能力。这种差异部分可以通过该层中异柠檬酸脱氢酶的较高比活性来解释。心内膜下线粒体的这些特性可能代表了对该层更大收缩性能的代谢支持。
