Fig. 9

Schematic representation of carbonic anhydrases and transporters in a choroid plexus epithelial (CPE) cell. CA12 is expressed on the basolateral side of the choroid plexus [42], CA4 and CA14 are generally membrane bound [4], yet their exact localization (luminal or basolateral) in the choroid plexus cell remains unresolved. CA2 and CA13 are both cytosolic [4, 45], whereas CA5B is found in mitochondria [79]. Not shown are CA6 and CA9, which are absent from mouse and human choroid plexus (Table 1), CA3, which is AZE insensitive [44], and CA11, which may be acatalytic [4]. CA isoforms 1, 7, 8, 10 and 15 were below detection level in rat choroid plexus (Table 1). The key transporters involved in CSF secretion NKCC1 and Na/K-ATPase are not affected by AZE treatment. The main candidates for mediating AZE-induced reduction in CSF secretion are the bicarbonate transporters: AE2 and NBCE/NBCn2 expressed at the basolateral membrane and NBCe2 expressed at the luminal membrane. The sphere area indicates transcriptional expression levels