Cardiovascular and haematological responses of Atlantic cod (Gadus morhua) to acute temperature increase
Cardiovascular and haematological responses of Atlantic cod (Gadus morhua) to acute temperature increase
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DOI：
10.1242/jeb.02319
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发表时间：
2006-08-01
影响因子：
2.8
通讯作者：
Gamperl, A. K.
中科院分区：
文献类型：
--
作者：
Gollock, M. J.;Currie, S.;Gamperl, A. K.
为了使鱼类在可能使它们接近其临界热最大值（CTM）的大的急性温度升高（即> 10.0摄氏度）下存活，鳃处的氧摄取和心血管系统的氧分配必须增加以匹配组织氧需求。为了检测温度急剧上升的影响（类似于CTM的1.7 ℃ h（-1））对大西洋鳕鱼的心肺生理学的影响，我们（1）对10.0 ℃驯化的鱼进行呼吸测定，同时使用Transonic探针测量体内心脏参数，（2）在7.0 ℃驯化的鳕鱼全血上构建了在一定温度范围内的体外氧结合曲线。心输出量（Q）和心率（f（H））都增加，直到接近鱼的CTM（22.2 +/- 0.2摄氏度），然后迅速下降。Q和f（H）的Q（10）值分别为2.48和2.12，这两个参数的增加与O-2消耗密切相关。与20.0 ℃和7.0 ℃相比，24.0 ℃下的血红蛋白（Hb）-氧结合曲线显示出明显的向下和向下移动，表明结合能力和亲和力均降低。此外，Hb水平在24.0 ℃下低于20.0 ℃和7.0 ℃。这可能是由于细胞肿胀，因为Hb样品的电泳没有表明蛋白质变性，并且在24.0 ℃时，Hb样品在预期波长（540 nm）处显示出峰值吸光度。我们的研究结果表明，心脏功能是不太可能限制代谢率在大西洋鳕鱼从纽芬兰，直到接近他们的CTM，我们认为，降低血氧结合能力可能有助于高原耗氧量。
For fish to survive large acute temperature increases (i.e. > 10.0 degrees C) that may bring them close to their critical thermal maximum (CTM), oxygen uptake at the gills and distribution by the cardiovascular system must increase to match tissue oxygen demand. To examine the effects of an acute temperature increase (similar to 1.7 degrees C h(-1) to CTM) on the cardiorespiratory physiology of Atlantic cod, we (1) carried out respirometry on 10.0 degrees C acclimated fish, while simultaneously measuring in vivo cardiac parameters using Transonic((R)) probes, and (2) constructed in vitro oxygen binding curves on whole blood from 7.0 degrees C acclimated cod at a range of temperatures. Both cardiac output (Q) and heart rate (f(H)) increased until near the fish's CTM (22.2 +/- 0.2 degrees C), and then declined rapidly. Q(10) values for Q and f(H) were 2.48 and 2.12, respectively, and increases in both parameters were tightly correlated with O-2 consumption. The haemoglobin (Hb)-oxygen binding curve at 24.0 degrees C showed pronounced downward and rightward shifts compared to 20.0 degrees C and 7.0 degrees C, indicating that both binding capacity and affinity decreased. Further, Hb levels were lower at 24.0 degrees C than at 20.0 degrees C and 7.0 degrees C. This was likely to be due to cell swelling, as electrophoresis of Hb samples did not suggest protein denaturation, and at 24.0 degrees C Hb samples showed peak absorbance at the expected wavelength (540 nm). Our results show that cardiac function is unlikely to limit metabolic rate in Atlantic cod from Newfoundland until close to their CTM, and we suggest that decreased blood oxygen binding capacity may contribute to the plateau in oxygen consumption.