Endothelial gaps and permeability of venules in rat tracheas exposed to inflammatory stimuli

An enumeration of endothelial gaps in rat trachea venules and a linking of these values to the extent of plasma extravasation following an inflammatory stimulus confirms endothelial gaps at intercellular junctions as focal openings. These openings comprise less than 3% of the luminal surface and differ from the leukocyte attachment region. A reduction in the driving force for the connective shift of the tracer or a decline in the conductance of the gaps may be responsible for the decline in Monastral blue extravasation that occurs prior to closure of gaps.