title: Evaluation of dose and route effects of platelet activating factor-induced extravasation in the guinea pig.
abstract: Platelet-activating factor (PAF) is a naturally occurring lipid that is reported to induce vessel hyperpermeability leading to loss of protein-rich plasma (extravasation). We have quantitated the systemic extravasation effects of synthetic PAF in the guinea pig by monitoring increases in hematocrit. When given intravenously (10-170 ng/kg), PAF produced dose-dependent increases in hematocrit, with maximal hemoconcentration developing in 5-7 min. In leukopenic animals the expected hematocrit increase was reduced by 57%. PAF given intra-arterially produced the dose-dependent changes in hematocrit similar to the intravenous effects of PAF. However, PAF given intraperitoneally (10-2500 micrograms/kg) was 800-1100-fold less effective than the other routes and hemoconcentration continued for 30-45 min until a maximal hematocrit was observed. These results show that PAF may markedly influence extravasation of plasma in a dose and route-dependent manner.
mesh_terms: D000818:Animals; D002199:Capillary Permeability / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D006168:Guinea Pigs; D006400:Hematocrit; D007269:Injections, Intra-Arterial; D007274:Injections, Intraperitoneal; D007275:Injections, Intravenous; D008297:Male; D010972:Platelet Activating Factor / Q000008:administration & dosage*
chemical_list: D010972:Platelet Activating Factor