Department of Biological Sciences, University of North Texas, 1155 Union Circle, Denton, TX 76203, United States.
Department of Marine Ecosystems and Society, Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL 33149-1098, United States.
Comp Biochem Physiol A Mol Integr Physiol. 2021 May;255:110915. doi: 10.1016/j.cbpa.2021.110915. Epub 2021 Feb 20.
In this study, we investigated the effect of acute increases in temperature on cardiovascular function of mahi-mahi (Coryphaena hippurus). We also describe, for the first time, an artery that supplies the gastrointestinal tract that originates from the fourth branchial artery. We used vascular casting to verify the anatomical location of this unique celiaco-mesenteric artery. We predicted that blood flow in this vessel would be correlated with the digestive state of the animal. Increasing water temperature from 25.0 to 30.5 °C resulted in a linear increase in heart rate (f) from 165 ± 4 beats∙minto 232 ± 7 beats∙min. Over this temperature range, f strongly correlated with water temperature (R = 0.79). At 31 °C f no longer correlated with water temperature, and at 34 °C f had dropped to 114 ± 19 beats∙min. Furthermore, we found that mahi are capable of maintaining constant cardiac output over a temperature range from 25 to 31 °C. Cardiac function appeared to be compromised at temperatures >31 °C. In fed anesthetized fish, blood flow was pulsatile in the celiaco-mesenteric artery and was not in fasted fish. In fed fish, blood flow in the left celiaco-mesenteric artery was 1.99 ± 0.78 ml·min·kg compared to the total cardiac output of 168.6 ± 12.7 ml·min·kg. The data suggest that mahi can differentially regulate gastric blood flow based on feeding state, which may explain the high digestive efficiency and very high growth rates of these pelagic predators.
在这项研究中，我们调查了温度急性升高对马鲛（Coryphaena hippurus）心血管功能的影响。我们还首次描述了一条源自第四鳃动脉供应胃肠道的动脉。我们使用血管铸型术来验证这条独特的腹腔肠系膜动脉的解剖位置。我们预测，这条血管中的血流将与动物的消化状态相关。将水温从 25.0°C 升高到 30.5°C 导致心率（f）从 165 ± 4 次·分钟线性增加到 232 ± 7 次·分钟。在这个温度范围内，f 与水温强烈相关（R = 0.79）。在 31°C 时，f 不再与水温相关，而在 34°C 时，f 降至 114 ± 19 次·分钟。此外，我们发现马鲛能够在 25 到 31°C 的温度范围内保持恒定的心输出量。心脏功能似乎在温度 >31°C 时受到损害。在麻醉的进食鱼中，腹腔肠系膜动脉中的血流是脉动的，而在禁食鱼中则不是。在进食鱼中，左腹腔肠系膜动脉的血流为 1.99 ± 0.78 ml·min·kg，而总心输出量为 168.6 ± 12.7 ml·min·kg。数据表明，马鲛可以根据进食状态差异调节胃血流量，这可能解释了这些海洋掠食者的高消化效率和非常高的生长速度。
