Aquaporins
Aquaporins also referred to as water channels, are proteins in the cell membrane that help water move across the membrane and allow the cell to control internal osmotic pressure. The two main aquaporin molecules of the central nervous system, AQP1, and AQP4, control the volume of extracellular and intracellular fluid, respectively, and regulate the movement of brain water and CSF. They also play a role in cytotoxic and vasogenic edema.