Issues

Summary: This Commentary considers how diverse stressors trigger a common set of molecular and physiological mechanisms that enable cardiac function to be maintained and optimised, a phenomenon known as ‘cardiac plasticity’.

Summary: Mitochondrial failure in tissues such as the heart and brain may underlie hyperthermic death. We consider in this Commentary how loss of mitochondrial cristae structure is a principal contributor to mitochondrial failure.

Summary: The metabolic cost of the heart, relative to whole-body metabolic rate, increases from approximately 2.5% in a mouse to 10% in an elephant, with implications for evolutionary and medical science.

Summary: The nutritional landscape is changing, altering diet quantity, quality and options. Altered diets impact cardiac plasticity and function, and thus whole-animal performance and resilience to environmental change.

Summary: This Commentary describes the functional interactions between cardiac output and other traits in the O₂ transport pathway that underlie the adaptive evolution of aerobic capacity.

Summary: Maximum heart rate can be assessed in anaesthetized fish during acute warming to characterize cardiac thermal performance and upper thermal limits. The method is high throughput, and broadly applicable.

Summary: This Review provides novel insights into the function of histidine-rich calcium-binding protein, an integrator of cardiomyocyte excitation–contraction coupling, as well as its interacting partner triadin and their evolution.

Summary: Remodeling of the heart caused by changes in hemodynamic load can lead to increases or decreases in function. This Review examines these responses and the cellular pathways that regulate them.

Summary: In this Review, we discuss the evolution and classification of the different architecture of the ventricular myocardium in vertebrates, with a particular focus on fishes.

Summary: The python heart is remarkably plastic and rapidly remodels in response to feeding. This Review highlights the unique and conserved mechanisms of adaptive cardiac growth in pythons and other species.

Summary: The development of the vertebrate heart is an intricate evolutionary process. A regular heartbeat, present in basal species, becomes organized by the conduction system, showing increasing complexity in advanced species.

Summary: The dive response is autonomically regulated, but many vertebrates can cognitively control cardiac function depending on the anticipated next dive. Here, we review the cognitive component of the diving response.

Summary: Molecular and cellular processes that regulate cardiac excitation–contraction coupling may influence the types of cardiac arrhythmias triggered by natural and anthropogenic environmental factors in fish.

Summary: We discuss the phenotypic consequences of developmental hypoxia on the cardiovascular system of oviparous vertebrates, focusing on species-specific responses, critical windows, high-altitude adaptations and interactive effects of other stressors.

Summary: This Review considers basic scientific research on crustacean cardiac physiology, and discusses how this knowledge can be applied in aquaculture and animal welfare.

Summary: Developmental plasticity of sarcoplasmic reticulum function, by chronic embryonic hypoxia, enables the cardiomyocytes of juvenile snapping turtles to tap into an additional source of Ca²⁺ to shorten normally during an anoxic exposure.

Summary: Cold exposure and acclimation of zebrafish induce time dependent changes to the cardiac phosphoproteome and proteome that support modification to contractile function, membrane composition and metabolic capacity.

Summary: Early-life exposure to natural conditions optimizes the pyramidal shape and bulbus alignment of Atlantic salmon hearts, highlighting the importance of water temperature and photoperiod for heart morphology.

Summary: Winter survival requires cardiac growth to supply elevated metabolism. Data in mice support physiological growth following chronic cold exposure, identifying an understudied form of hypertrophy.

Summary: Complex I is an important modulator of the thermal sensitivity of mitochondria and age affect mitochondrial functions at high temperature.

Summary: Coronary blockages impair heat tolerance and aerobic performance in wild Pacific salmon. Natural coronary blockages could thus have important implications for the conservation of migratory salmon.

Summary: Analysis of cardiac and red skeletal muscle of crucian carp exposed to anoxia shows both mitochondrial function and morphology are maintained, possibly through the continued activity of complexes I–III in the electron transport system.

Summary: T₄-induced metamorphosis in axolotls (Ambystoma mexicanum) is associated with remodelling of action potentials and ionic currents in the heart.

Summary: Negative auricle pressure caused by ventricular contraction drives pulsative venous return from the branchial vessels via the afferent oblique vein in Mytilus.