Organization of choroid plexus epithelial and endothelial cell tight junctions and regulation of claudin-1,-2 and-5 expression by protein kinase C

Claudins are components of the tight junctional complex in epithelial and e ndothelial cells. We characterized the composition of tight junctions in th e choroid plexus of the lateral ventricle in the rat brain and tested wheth er protein kinase C induced changes in their composition. Claudin-1, -2 and -5 were present: in the epithelial cells at and near the tight junctions, respectively. In the endothelial cells, claudin-5 was stronger expressed th an claudin-1 and -2. Twenty-four hours after the phorbolester injection int o the ventricle, claudin-1 immunoreactivity of the epithelial cells was inc reased and spread to the cytoplasm. The claudin-2 and -5 immunoreactivities were reduced. These findings are consistent with an influence of protein k inase C on the composition of the tight junctions in the choroid plexus. Ne uroReport 11:1427-1431 (C) 2000 Lippincott Williams & Wilkins.