The sodium pump and hypertension: A physiological role for the cardiac glycoside binding site of the Na,K-ATPase

摘要

The Na,K-ATPase (or Na pump) is an integral membrane protein that transports Na~+ and K~+ across the plasma membrane of almost all animal cells and couples this work to the hydrolysis of the terminal phosphate bond of ATP (1). A significant fraction (up to ≈30%) of the ATP generated by cell metabolism is dedicated to this active transport process. The electrical gradient created by the Na pump is essential for the excitable activity of muscle and nerve tissue, and the inwardly directed Na gradient maintained by the Na pump is used in most cells and organs to drive the uptake and accumulation of a wide range of essential nutrients and cellular substrates and to reduce cell calcium and proton concentrations.