Potassium homeostasis during exercise in domestic species: the role of the sodium-potassium pump in skeletal muscle

In 1997, Jens Christian Skou was awarded the Nobel prize in Chemistry for his discovery and elegant description, some 40 years earlier, of the sodium-potassium (Na+,K+) pump in crab nerve fibres [37]. It is now widely accepted that this cation transport system is essential for cell function, and that it plays a central role in the Na+,K+ homeostasis of virtually all animals [4],[6]. Since its identification, the Na+,K+ pump has been the subject of numerous investigations, including ones on the mechanism for controlling ion transport through the pump, the detailed molecular structure of the pump and its regulation. Regulation of plasma K+, both long-term (by kidney Na+,K+-ATPase), and acute (by skeletal muscle Na+,K+-ATPase, during exercise), have been questions frequently addressed by physiologists. Most of this work has been performed using small odents and man [4,5,6], however, the following review will discuss the up- and down regulation of the Na+,K+ pump concentration in the skeletal muscle of domestic animal species, including cats, dogs, horses and cattle