Notes: During brain development endothelial cells may participate in neuronal recruitment, by providing neurotrophic support to new neurons. Levels of BDNF, NGF, NT-3, and NT-4 mRNAs in cultured adult human brain endothelial cells and human umbilical vascular endothelial cells were determined. The localization of BDNF within these cells was done by immunocytochemistry with the Anti-Human BDNF pAb at a 1:1000 dilution. Cells were fixed with 4% paraformaldehyde with 0.1% glutaraldehyde and permeabilized with PBS with 0.1% saponin/1% rabbit serum. The Anti-Chicken IgY, HRP Conjugate (1:200 dilution) and a DAB substrate were used to visualize staining. (2392)