Hansen C A, Sidell B D
Am J Physiol. 1983 Mar;244(3):R356-62. doi: 10.1152/ajpregu.1983.244.3.R356.
Oxygen tensions in the major venous inputs to the systemic and portal-vein hearts of normoxic Atlantic hagfish (12.3 +/- 1.7 and 11.0 +/- 1.6 mmHg, respectively) are low compared with typical vertebrate values. Anoxia and poisoning with cyanide and azide do not significantly affect in situ performance of the systemic heart. Idoacetate poisoning, however, results in a significant decrease in cardiac performance of the systemic heart to 12% of the initial value after 3 h. Activities of mitochondrial enzymes of hagfish ventricle suggest a small potential for aerobic metabolism compared with those in the aerobic ventricle of Atlantic cod. Activities of enzymes of carbohydrate metabolism indicate similar anaerobic capacity in hagfish and cod ventricle. The ratio of pyruvate kinase to cytochrome c oxidase, an index of anaerobic to aerobic capacity, is 5.6 times greater in hagfish than cod ventricle. Metabolite concentrations in freeze-clamped ventricles of normoxic and hypoxic hagfish indicate hypoxia-induced activation of glycogenolysis, enhanced substrate flow across 6-phosphofructokinase, and an apparent secondary constriction of glycolysis at the level of glyceraldehyde-phosphate dehydrogenase. Carbohydrate utilization via the glycolytic pathway appears essential for maintenance of cardiac performance in both normoxic and anoxic hagfish. Under conditions of severe hypoxia, ATP provision is probably met by anaerobic glycolysis.
与典型的脊椎动物数值相比，常氧条件下大西洋盲鳗体循环心脏和门静脉心脏的主要静脉输入中的氧分压较低（分别为12.3±1.7 mmHg和11.0±1.6 mmHg）。缺氧以及氰化物和叠氮化物中毒对体循环心脏的原位功能没有显著影响。然而，碘乙酸盐中毒会导致体循环心脏的心脏功能在3小时后显著下降至初始值的12%。与大西洋鳕鱼有氧心室中的线粒体酶活性相比，盲鳗心室中的线粒体酶活性表明其有氧代谢潜力较小。碳水化合物代谢酶的活性表明盲鳗和鳕鱼心室中的无氧能力相似。丙酮酸激酶与细胞色素c氧化酶的比值（无氧能力与有氧能力的指标）在盲鳗心室中比鳕鱼心室中高5.6倍。常氧和低氧盲鳗经冷冻钳夹处理的心室中的代谢物浓度表明，缺氧诱导了糖原分解的激活，增强了底物通过6-磷酸果糖激酶的流量，并且在磷酸甘油醛脱氢酶水平上糖酵解明显出现二次抑制。在常氧和缺氧的盲鳗中，通过糖酵解途径利用碳水化合物对于维持心脏功能似乎至关重要。在严重缺氧的条件下，可能通过无氧糖酵解来提供ATP。
