Na-dependent transporters: The backbone of astroglial homeostatic function.

Astrocytes are the principal homeostatic cells of the central nerves system (CNS) that support the CNS function at all levels of organisation, from molecular to organ. Several fundamental homeostatic functions of astrocytes are mediated through plasmalemmal pumps and transporters; most of which are also regulated by the transplasmalemmal gradient of Na ions. Neuronal activity as well as mechanical or chemical stimulation of astrocytes trigger plasmalemmal Na fluxes, which in turn generate spatio-temporally organised transient changes in the cytosolic Na concentration, which represent the substrate of astroglial Na signalling. Astroglial Na signals link and coordinate neuronal activity and CNS homeostatic demands with the astroglial homeostatic response.