Ultradian oscillation in the heart rate of rainbow trout (Oncorhynchus mykiss)

1993 ◽  
Vol 106 (2) ◽  
pp. 183-186 ◽  
Author(s):  
Luis De Vera ◽  
Imants G Priede
Keyword(s):  
Heart Rate ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Rainbow Trout Oncorhynchus Mykiss

How the efficiency of rainbow trout (Oncorhynchus mykiss) ventricular muscle changes with cycle frequency

2002 ◽  
Vol 205 (5) ◽  
pp. 697-706 ◽  
Author(s):  
Claire L. Harwood ◽  
Iain S. Young ◽  
John D. Altringham
Keyword(s):  
Heart Rate ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Cardiac Muscle ◽  
Power Output ◽  
Energy Cost ◽  
Total Efficiency ◽  
Ventricular Muscle ◽  
Cycle Frequency ◽  
Rainbow Trout Oncorhynchus Mykiss

SUMMARYDifferent species of animals require different cardiac performance and, in turn, their cardiac muscle exhibits different properties. A comparative approach can reveal a great deal about the mechanisms underlying myocardial contraction. Differences in myocardial Ca2+ handling between fish and mammals suggest a greater energy cost of activation in fish. Further, while there is considerable evidence that heart rate (or cycle frequency) should have a profound effect on the efficiency of teleost cardiac muscle, this effect has been largely overlooked. We set out to determine how cycle frequency affects the power output and efficiency of rainbow trout (Oncorhynchus mykiss) ventricular muscle and to relate this to the heart’s function in life. We measured power output and the rate of oxygen consumption (V̇O2) and then calculated efficiency over a physiologically realistic range of cycle frequencies.In contrast to mammalian cardiac muscle, in which V̇O2 increases with increasing heart rate, we found no significant change in V̇O2 in the teleost. However, power output increased by 25 % as cycle frequency was increased from 0.6 to 1.0 Hz, so net and total efficiency increased. A maximum total efficiency of 20 % was achieved at 0.8 Hz, whereas maximum power output occurred at 1.0 Hz. We propose that, since the heart operates continuously, high mechanical efficiency is a major adaptive advantage, particularly at lower heart rates corresponding to the more commonly used slower, sustainable swimming speeds. Efficiency was lower at the higher heart rates required during very fast swimming, which are used during escape or prey capture.If a fixed amount of Ca2+ is released and then resequestered each time the muscle is activated, the activation cost should increase with frequency. We had anticipated that this would have a large effect on the total energy cost of contraction. However, since V̇O2 remains constant, less oxygen is consumed per cycle at high frequencies. We suggest that a constant V̇O2 would be observed if the amount of activator Ca2+ were to decrease with frequency. This decrease in activation energy is consistent with the decrease in the systolic intracellular Ca2+ ([Ca2+]i) transient with increasing stimulation frequency seen in earlier studies.

scholarly journals A rapid intrinsic heart rate resetting response with thermal acclimation in rainbow trout, Oncorhynchus mykiss

2020 ◽  
Vol 223 (12) ◽  
pp. jeb215210 ◽  
Author(s):  
Rachel L. Sutcliffe ◽  
Shaorong Li ◽  
Matthew J. H. Gilbert ◽  
Patricia M. Schulte ◽  
Kristi M. Miller ◽  
...  
Keyword(s):  
Heart Rate ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Thermal Acclimation ◽  
Intrinsic Heart Rate ◽  
Rainbow Trout Oncorhynchus Mykiss

Prospects and pitfalls of using heart rate bio-loggers to assess the welfare of rainbow trout (Oncorhynchus mykiss) in aquaculture

Aquaculture ◽  
2019 ◽  
Vol 509 ◽  
pp. 188-197 ◽  
Author(s):  
J. Brijs ◽  
E. Sandblom ◽  
M. Rosengren ◽  
K. Sundell ◽  
C. Berg ◽  
...  
Keyword(s):  
Heart Rate ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Rainbow Trout Oncorhynchus Mykiss

Adrenergic control of venous capacitance during moderate hypoxia in the rainbow trout (Oncorhynchus mykiss): role of neural and circulating catecholamines

2006 ◽  
Vol 291 (3) ◽  
pp. R711-R718 ◽  
Author(s):  
Erik Sandblom ◽  
Michael Axelsson
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cardiac Output ◽  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Blood Volume ◽  
Body Mass ◽  
Venous Capacitance ◽  
Moderate Hypoxia ◽  
Rainbow Trout Oncorhynchus Mykiss

Central venous blood pressure (Pven) increases in response to hypoxia in rainbow trout ( Oncorhynchus mykiss), but details on the control mechanisms of the venous vasculature during hypoxia have not been studied in fish. Basic cardiovascular variables including Pven, dorsal aortic blood pressure, cardiac output, and heart rate were monitored in vivo during normoxia and moderate hypoxia (PWO2 = ∼9 kPa), where PWO2 is water oxygen partial pressure. Venous capacitance curves for normoxia and hypoxia were constructed at 80–100, 90–110, and 100–120% of total blood volume by transiently (8 s) occluding the ventral aorta and measure Pven during circulatory arrest to estimate the mean circulatory filling pressure (MCFP). This allowed for estimates of hypoxia-induced changes in unstressed blood volume (USBV) and venous compliance. MCFP increased due to a decreased USBV at all blood volumes during hypoxia. These venous responses were blocked by α-adrenoceptor blockade with prazosin (1 mg/kg body mass). MCFP still increased during hypoxia after pretreatment with the adrenergic nerve-blocking agent bretylium (10 mg/kg body mass), but the decrease in USBV only persisted at 80–100% blood volume, whereas vascular capacitance decreased significantly at 90–110% blood volume. In all treatments, hypoxia typically reduced heart rate while cardiac output was maintained through a compensatory increase in stroke volume. Despite the markedly reduced response in venous capacitance after adrenergic blockade, Pven always increased in response to hypoxia. This study reveals that venous capacitance in rainbow trout is actively modulated in response to hypoxia by an α-adrenergic mechanism with both humoral and neural components.

scholarly journals It takes time to heal a broken heart: Ventricular plasticity improves heart performance after myocardial infarction in rainbow trout, Oncorhynchus mykiss

2021 ◽  
Author(s):  
Lucas A. Zena ◽  
Andreas Ekström ◽  
Albin Gräns ◽  
Catharina Olsson ◽  
Michael Axelsson ◽  
...  
Keyword(s):  
Heart Rate ◽  
Rainbow Trout ◽  
Coronary Artery ◽  
Oncorhynchus Mykiss ◽  
Coronary Occlusion ◽  
Morphological Characteristics ◽  
Coronary Artery Ligation ◽  
Resting Heart Rate ◽  
Rainbow Trout Oncorhynchus Mykiss

Coronary arteriosclerosis is a common feature of both wild and farmed salmonid fishes and may be linked to stress-induced cardiac pathologies. Yet, the plasticity and capacity for long-term myocardial restructuring and recovery following a restriction in coronary blood supply is unknown. Here, we analyzed the consequences of acute (3 days) and chronic (from 33 to 62 days) coronary occlusion (i.e., coronary artery ligation) on cardiac morphological characteristics and in vivo function in juvenile rainbow trout, Oncorhynchus mykiss. Acute coronary occlusion resulted in elevated resting heart rate and decreased inter-beat variability, which are both markers of autonomic dysfunction following acute myocardial ischemia, along with severely reduced heart rate scope (maximum – resting heart rate) relative to sham-operated trout. We also observed a loss of myocardial interstitial collagen and compact myocardium. Following long-term coronary- ligation, resting heart rate and heart rate scope normalized relative to sham-operated trout. Moreover, a distinct fibrous collagen layer separating the compact myocardium into two layers had formed. This may contribute to maintain ventricular integrity across the cardiac cycle, or alternatively, demark a region of the compact myocardium that continues to receive oxygen from the luminal venous blood. Taken together, we demonstrate that rainbow trout may cope with the aversive effects caused by coronary artery obstruction through plastic ventricular remodeling, which, at least in part, restores cardiac performance and myocardium oxygenation.

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