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Mediators of Inflammation
Volume 1, Issue 6, Pages 403-409

Five steps in leukocyte extravasation in the microcirculation by chemoattractants

1Department of Pharmacology, Kitasato University School of Medicine, Kanagawa, Sagamihara 228, Japan
2Department of Anatomy, Kitasato University School of Medicine, Kanagawa, Sagamihara 228, Japan
3Department of Biology, Faculty of General Education, Yamagata University, Yamagata 990, Japan

Copyright © 1992 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


For in vivo study of the phenomena observed in vitro, PMN (polymorphonuclear leukocyte) extravasation was analysed quantitatively in the microcirculation of the hamster cheek pouch using a video system. Topical application of leukotriene B4 or N-formyl-methionylleucyl- phenylalanine increased dose dependently the number of PMNs adhering to the venules. Eighty to 90% of the adhering PMNs disappeared from the vascular lumen into the venular wall within 10-12 rain after the adhesion. After PMNs had passed through the endothelial cell layer, they remained in the venular wall for more than 30 min after application of the chemoattractants and appeared in the extravascular space. Thus, the process could be divided into five steps: (1) rolling and (2) adhesion to the endothelium, (3) passage through the endothelial layer (4) remaining in the venular wall, and (5) passage through the basement membrane.