CANINE JUGULAR-VEIN ENDOTHELIAL-CELL MONOLAYERS IN-VITRO - VASOMEDIATOR-ACTIVATED DIFFUSIVE ALBUMIN PATHWAY

Cultured canine jugular vein endothelial cells were seeded on polycarb onate filters to create an in vitro permeability assay. The calculated diffusive permeability coefficient for FITC-BSA across untreated mono layers was 1.1 +/- 0.4 X 10(-6) cm/s. After 15-min incubations with ei ther histamine or bradykinin, the resistance to albumin flux across th e monolayers was reduced significantly. Diffusive albumin permeability coefficients were 3.4 +/- 1.8 X 10(-6) and 4.1 +/- 2.0 X 10(-6) cm/s, respectively. Ultrastructural morphometric analyses of the endothelia l cell monolayers served to define uniform dimensions of intercellular clefts and similar plasmalemmal vesicle densities in the untreated an d the vasomediator-activated monolayers. These results are consistent with the interpretation that the vasomediator-activated pathway across the venous endothelial monolayers is not dependent on sustained inter cellular gap formation or sustained expansion of the plasmalemmal vesi cle population for the 15-min observation periods. Whether the increas ed albumin flux is dependent on transient gap formation or on physical changes within the venous endothelial cell glycocalyx remains to be t ested.