[Microcirculatory and vascular permeability disorders during short-term immobilization stress]

Immobilization of rats for 1 or 3 hours increased the vascular permeability for colloid carbon particles and led to disturbances of the microcirculation in microvessels (formation of aggregates, appearance of "plasmatic vessels", opening of arteriolo-venular shunts). A prominent role of histamine, released from mast cells without any degranulation of the cells, in the pathogenesis of these disturbances was shown. It is supposed that the histamine release served as the trigger mechanism in the development of vascular permeability disturbances in the course of prolonged immobilization stress.