Bailey J R, Driedzic W R
Department of Biology, Mount Allison University, Sackville, New Brunswick, Canada.
J Exp Biol. 1988 Mar;135:301-15. doi: 10.1242/jeb.135.1.301.
Cardiac myoglobin plays a role in oxygen consumption and has a protective effect during periods of hypoxia, but little is known about the role of myoglobin during periods of ischaemia. Myoglobin-rich sea raven hearts and myoglobin-poor ocean pout hearts were isolated and perfused at varying flow rates and under conditions of low and high oxygen demand to assess the role of myoglobin in oxygen extraction. In the myoglobin-rich hearts, oxygen extraction remained constant over the flow range. In the myoglobin-poor hearts, oxygen extraction was significantly elevated, relative to controls, at the lower flow rates but decreased as the flow rate increased. In hearts where myoglobin was inactivated by an oxidizing agent, oxygen extraction was similar to that observed in myoglobin-poor hearts. Under conditions of high oxygen demand, myoglobin-rich hearts again showed a constant oxygen extraction over the flow range. Myoglobin-inactivated hearts had a significantly elevated oxygen extraction at low flows, and this decreased as flow rate increased. These data suggest that myoglobin renders oxygen extraction by fish hearts independent of the rate of perfusion.
心肌肌红蛋白在氧消耗中起作用，并且在缺氧期间具有保护作用，但关于肌红蛋白在缺血期间的作用知之甚少。分离出富含肌红蛋白的海鸦心脏和肌红蛋白含量低的美洲绵鳚心脏，并在不同流速以及低氧需求和高氧需求条件下进行灌注，以评估肌红蛋白在氧提取中的作用。在富含肌红蛋白的心脏中，氧提取在整个流速范围内保持恒定。在肌红蛋白含量低的心脏中，相对于对照组，在较低流速下氧提取显著升高，但随着流速增加而降低。在肌红蛋白被氧化剂灭活的心脏中，氧提取与肌红蛋白含量低的心脏中观察到的情况相似。在高氧需求条件下，富含肌红蛋白的心脏在整个流速范围内再次显示出恒定的氧提取。肌红蛋白失活的心脏在低流速下氧提取显著升高，并且随着流速增加而降低。这些数据表明，肌红蛋白使鱼心脏的氧提取与灌注速率无关。
