Changes in leucocyte numbers without diapedesis in rats given platelet-activating factor (PAF-acether).
Changes occurring in the blood and the peritoneal cavity following the intraperitoneal injection of platelet-activating factor (PAF-acether) into rats were compared with those when antigen was injected intraperitoneally into actively sensitised rats. A blood eosinophilia had been produced in the rats by an intravenous injection of Sephadex G200 6 days before either challenge. 5 min after PAF-acether, the total number of cells in the peritoneal washings had decreased and the concentration of extravasated dye-labelled plasma protein had increased with no change in histamine levels. On the other hand, antigen at this time produced nor only a decrease in cells and an increase in dye but also an increase in histamine concentration. Only antigen produced a cellular infiltration into the peritoneal cavity with an increase in numbers of neutrophils in the peritoneal washings at 4 h and of mononuclear cells and eosinophils at 24 h. In the blood at 4 h after either challenge, there was a neutrophilia and an eosinopenia. When PAF-acether and antigen were injected together into actively sensitised rats, leucocyte counts in the peritoneal washings increased by a similar amount, both at 4 and 24 h, as those in rats given antigen alone.
D000818:Animals; D002465:Cell Movement; D003911:Dextrans / Q000633:toxicity; D004802:Eosinophilia / Q000097:blood / Q000139:chemically induced / Q000473:pathology*; D007274:Injections, Intraperitoneal; D007958:Leukocyte Count / Q000187:drug effects*; D007962:Leukocytes / Q000502:physiology*; D008297:Male; D010529:Peritoneal Cavity / Q000166:cytology; D010972:Platelet Activating Factor / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains
D003911:Dextrans; D010972:Platelet Activating Factor; C025614:sephadex