Effect of platelet activating factor on endothelial permeability to plasma macromolecules.
We have examined the effect of intrajugular administration of platelet activating factor (PAF-C16) on vascular permeability in the guinea pig. To examine the loss of selective endothelial permeability, the extravasative effect of PAF was assessed by monitoring hemoconcentration and the plasma loss of 125I-albumin (6.7 nm), 125I-low density lipoproteins (22.0 nm) or 125I-very low density lipoproteins (62.1 nm). Extravasation was dose-dependent and began 1 min after PAF administration, continuing for 5-7 min. During extravasation, there was no evidence for selective plasma retention of any of the labeled plasma tracers, as measured by plasma radioactivity. These results suggest that PAF-induced extravasation is dose-dependent, with increases in vascular permeability sufficient to permit similar plasma efflux rates of albumin, low density lipoproteins and very low density lipoproteins.
D000818:Animals; D001798:Blood Proteins / Q000378:metabolism*; D002199:Capillary Permeability / Q000187:drug effects*; D004727:Endothelium / Q000166:cytology; D006168:Guinea Pigs; D007457:Iodine Radioisotopes; D008077:Lipoproteins, LDL / Q000097:blood / Q000378:metabolism; D008079:Lipoproteins, VLDL / Q000097:blood / Q000378:metabolism; D010972:Platelet Activating Factor / Q000494:pharmacology*; D012711:Serum Albumin, Radio-Iodinated / Q000378:metabolism; D013194:Staining and Labeling; D013997:Time Factors
D001798:Blood Proteins; D007457:Iodine Radioisotopes; D008077:Lipoproteins, LDL; D008079:Lipoproteins, VLDL; D010972:Platelet Activating Factor; D012711:Serum Albumin, Radio-Iodinated