ARE IN-VITRO BLOOD-BRAIN-BARRIER MODEL - COCULTURES BETWEEN ENDOTHELIAL-CELLS AND ORGANOTYPIC BRAIN SLICE CULTURES

This communication describes a novel in vitro blood-brain barrier (BBB ) model: organotypic slice cultures from the central nervous system we re overlaid on endothelial cell monolayers grown on permeable membrane s, Morphological, electrophysiological, and microdialysis approaches w ere carried out to characterize and validate this model, After 10 days in coculture, morphological studies reveal the presence of tight junc tions, Electrophysiological recordings of neuronal activity performed on organotypic cultures with or without an endothelial cell monolayer show that amplitude of evoked responses were comparable, indicating go od viability of cocultures after 2 weeks. Perfusion of known BBB perme able or nonpermeable molecules was used to test the coculture tightnes s in conjunction with electrophysiological or microdialysis approaches : application of glutamate (Glu), which doesn't easily cross the BBB, triggers off rhythmic activity only in control cultures, whereas epile ptogenic activity was observed in both control cultures and cocultures during perfusions with picrotoxin, a molecule that can diffuse throug h the BBB, Finally, the microdialysis technique was used to determine the permeability of molecules coming from the perfusion chamber: L-dop a, dopamine, and Glu were employed to assess the selective permeabilit y of the coculture model, Thus, these results indicate that the in vit ro model described possesses characteristics similar to those of the B BB in situ and that cocultures of organotypic slices and endothelial c ell monolayers have potential as a powerful tool for studying biochemi cal mechanisms regulating BBB function and drug delivery to the centra l nervous system.