A mechanism by which sodium ions are transported out of a eukaryotic cell across the plasma membrane. The process requires energy in the form of ATP, being a form of active transport. The most important type is sodium/potassium ATPase (Na+/K+ ATPase), which is a membrane transport protein that exchanges sodium ions (Na+) for potassium ions (K+), thus maintaining the differential concentrations of each ion across the plasma membrane. This differential is vital to cellular function, e.g. in establishing the resting potential of a neuron.
Subjects: Science and Mathematics — Medicine and Health.