Representative indirect fluorescent digital photomicrographs of cryostat axial sections of normal adult sural nerves show UEA-1-positive endothelial cells (green; A, E, I, M) with expression of CLDN5, ESAM, MPDZ and CDH6 (red; B, F, J, N respectively) restricted to endoneurial microvessels and fenestrated epineurial macrovessels shown in the merged images at lower and higher magnifications (yellow/ orange). CDH6 is also expressed by large diameter axons (M-P). Expression of these proteins by both endoneurial microvascular and epineurial macrovascular endothelium suggests endothelial-specific, non-restrictive barrier functions at the normal adult human BNB. White arrows demonstrate positively staining endoneurial microvessels. Blue (DAPI) staining indicates nuclei. Scale bar 500 μm for A-C, E-G, I-K, M-O, and 125 μm for D, H, L and P.