Fig. 2

Transepithelial ion transport at the choroid plexus. Movement of solutes from the interstitial space to the intracellular environment via the basolateral membrane are shown—AE2 (epithelial anion exchanger 2), AQP1 (aquaporin 1), NBC (sodium bicarbonate coexchanger) and KCC2 (potassium chloride cotransporter). The movement from the intracellular environment to the CSF in the ventricles via the apical membrane is also shown—Na⁺–K⁺–ATPase, AQP1, NKCC1 (sodium–potassium-chloride cotransporter 1), NHE (sodium–hydrogen exchanger) and K⁺ channel