Mechanisms That Determine the Internal Environment of the Developing Brain: A Transcriptomic, Functional and Ultrastructural Approach
Figure 5
Localisation of biotin ethylenediamine (BED, 286Da) following intraventricular injection.
The small tracer, biotin ethylenediamine, was injected intraventricularly to assess barrier function in choroid plexus in the E15 rat embryo (A–C) and adult (D–F). A and D are semithin sections stained with toluidine blue; B, C, E and F are electron micrographs. Note that the tracer was abundant on the outside of epithelial cells but was restricted by the epithelial tight junctions (TJ), present towards the apical side of these cells and was not visible further into the intercellular cleft. These data suggest that the tight junctions present between intimately apposed plexus epithelium are functional in E15 animals to the same extent as in the adult. Scale bars: A, D = 50 µm, B, E = 5 µm, C, F = 1 µm. Abbreviations: BV, blood vessel; CSF, cerebrospinal fluid; N, nucleus; TJ, tight junction.