Astrocyte-Selective Volume Increase in Elevated Extracellular Potassium Conditions Is Mediated by the Na/K ATPase and Occurs Independently of Aquaporin 4.

Astrocytes and neurons have been shown to swell across a variety of different conditions, including increases in extracellular potassium concentration (^[K]). The mechanisms involved in the coupling of K influx to water movement into cells leading to cell swelling are not well understood and remain controversial. Here, we set out to determine the effects of ^[K] on rapid volume responses of hippocampal CA1 pyramidal neurons and stratum radiatum astrocytes using real-time confocal volume imaging.