Vascular events in inflammation.

Seven topics of vascular events in inflammation are discussed independently: (1) It is pointed out that too frequently generalizations have been made of vascular phenomena registered in one specific situation, and evidence is given that the existence of a characteristic vascular reaction pattern in the inflammatory processes is doubtful. (2) Considering the results of recent experiments, it is suggested that the role of the nervous system in inflammation should be reassessed. Although its influence seems to be of a minor nature in many "laboratorial" situations, it is of primary importance when nerves are stimulated by electric antidromic excitations and may be relevant in injuries sufficiently severe to damage peripheral nerves. (3) Attention is called to the diversity of vascular leakage types. (4) The dissociation between vascular permeability, oedema and diapedesis is presented and discussed. (5 and 6) The ultrastructural features and the role of endothelial vesicles and junctions are updated and commented upon. (7) The barrier effect of the basement membrane in vascular permeability alterations is discussed and an alternative hypothesis is suggested: the basal lamina does not usually retain particles or blood cells and the temporary halt of elements in the ground substance may be due to the pressure and flux differences in and outside the vessels.