DELTA-AMINOLEVULINIC-ACID TRANSPORT THROUGH BLOOD-BRAIN-BARRIER

1. delta-Aminolevulinic acid (ALA) and gamma aminobutyric acid (GABA) transport through the rat blood-brain barrier (BBB) was studied. 2. GA BA transport (K-m=3.2+/-0.1 mu M and V-max=0.299+/-0.045 mu mol/mg pro tein min) is probably mediated by a permease similar to Saccharomyces cerevisise PUT4; this result also indicates that the isolated capillar ies are metabolically active. 3. ALA incorporation into rat brain endo thelial cells is not detected even in capillaries treated to expose th e luminal surface. 4. Previous evidence indicates that ALA can cross t he BBB from blood to brain; so we conclude that, with the methodology used here, transport in the luminal membrane of the capillaries cannot be investigated. (C) 1998 Elsevier Science Inc.