Importance of the coronary circulation for cardiac and metabolic performance in rainbow trout (Oncorhynchus mykiss)

Cardiac oxygenation is achieved via both coronary arterial and luminal venous oxygen supply routes in many fish species. However, the relative importance of these supplies for cardiac and aerobic metabolic performance is not fully understood. Here, we investigated how coronary artery ligation in rainbow trout (Oncorhynchus mykiss), implanted with heart rate loggers, affected cardiorespiratory performance in vivo. While coronary ligation significantly elevated resting heart rate, the standard metabolic rate was unchanged compared to sham treated controls. However, coronary ligation reduced the maximum metabolic rate while heart rate remained unchanged following enforced exercise. Thus, coronary ligation reduced metabolic and heart rate scopes by 29 and 74%, respectively. Our findings highlight the importance of coronary oxygen supply for overall cardiorespiratory performance in salmonid fish, and suggest that pathological conditions that impair coronary flow (e.g., coronary arteriosclero...在众多鱼类物种中，心脏供氧可通过冠状动脉（coronary artery）与管腔静脉两条供氧途径实现。然而，这两条供氧途径对于心脏有氧代谢功能的相对重要性尚未完全明确。本研究针对植入心率记录仪（heart rate loggers）的虹鳟（Oncorhynchus mykiss）开展冠状动脉结扎实验，探究其对体内心肺功能的影响。尽管冠状动脉结扎显著升高了静息心率，但与假手术对照组（sham treated controls）相比，标准代谢率（standard metabolic rate）未出现明显变化。然而，在强制运动后，冠状动脉结扎组的最大代谢率（maximum metabolic rate）出现下降，而心率未发生明显改变。由此可见，冠状动脉结扎使代谢范围（metabolic scope）与心率范围（heart rate scope）分别降低了29%与74%。本研究结果凸显了冠状动脉供氧对鲑科鱼类（salmonid fish）整体心肺功能的重要性，并提示损害冠状动脉血流的病理状态（如冠状动脉粥样硬化……）