Bailey J R, Driedzic W R
Am J Physiol. 1986 Dec;251(6 Pt 2):R1144-50. doi: 10.1152/ajpregu.1986.251.6.R1144.
Myoglobin, an intracellular O2-binding protein, plays a protective role in maintaining performance of isolated fish hearts under hypoxic conditions. This study was designed to test the hypothesis that the protein contributes to O2 consumption under conditions of increased O2 demand or hypoxia. Isolated myoglobin-rich sea raven (Hemitripterus americanus) hearts and myoglobin-poor ocean pout (Macrozoarces americanus) hearts were perfused under conditions of changing partial pressure of O2 (PO2) and afterload. Sea raven hearts maintained O2 consumption and cardiac performance at low PO2 and high afterload, whereas ocean pout hearts did not. In other cases sea raven and ocean pout hearts were treated with hydroxylamine, which renders myoglobin incapable of binding O2, and subjected to changing PO2 and afterload. Sea raven hearts could not maintain O2 consumption and cardiac performance, whereas hydroxylamine treatment had no effect on O2 consumption in ocean pout hearts under these conditions. These data provide the first evidence to support the concept that myoglobin plays a role in O2 consumption of hearts.
肌红蛋白是一种细胞内氧结合蛋白，在低氧条件下对维持离体鱼心脏的功能起着保护作用。本研究旨在验证这一假说：在氧气需求增加或缺氧条件下，该蛋白有助于氧气消耗。在氧气分压（PO2）和后负荷不断变化的条件下，对富含肌红蛋白的海鸦（美洲半跗躄鱼）离体心脏和肌红蛋白含量低的美洲绵鳚离体心脏进行灌注。海鸦心脏在低PO2和高后负荷条件下能维持氧气消耗和心脏功能，而美洲绵鳚心脏则不能。在其他实验中，用羟胺处理海鸦和美洲绵鳚心脏，使肌红蛋白无法结合氧气，然后改变PO2和后负荷。在此条件下，海鸦心脏无法维持氧气消耗和心脏功能，而羟胺处理对美洲绵鳚心脏的氧气消耗没有影响。这些数据首次提供了证据支持肌红蛋白在心脏氧气消耗中起作用这一概念。
