Development of endothelial paracellular clefts and their tight junctions in the pial microvessels of the rat.

摘要: The microvessels of the pia mater lack an investment with astrocyte processes but nonetheless have a high transendothelial electrical resistance which has caused them to be regarded as part blood-brain barrier. This is known acquired in perinatal period. aim our study was relate physiological changes differentiation endothelial paracellular clefts and especially their tight junctions provide basis for barrier vessels. Tight cell pial were examined by transmission electron microscopy using goniometric tilting reveal measure membrane separations at fetal, postnatal adult rats. These junctional narrowed over period (E16:6.3 nm, D1:6.4 D7:5.4 nm) differentiated into two groups stage: one separation 2.8 nm staining characteristics non-brain junctions, other no detectable characteristic junctions. patchy incomplete barrier-like form could result either from non-uniform exposure inductive signals or local variation responsiveness such agents. Although these junction organization may related increase period, we not yet identified any sharply defined structural change coincides this event.