title: Platelet-activating factor in the inflammatory exudate in the anaphylactic phase of allergic inflammation in rats.
abstract: Using a model of allergic inflammation of air pouch type in rats, the platelet-activating factor (PAF) in the pouch fluid in the anaphylactic phase was analyzed. Anaphylactic reaction was induced by injecting an antigen (azobenzene-arsonate-conjugated acetyl bovine serum albumin) solution into a subcutaneous air pouch preformed on the dorsum of immunized rats. The pouch fluid was collected 30 min after the antigenic challenge, and chloroform extract was subjected to normal phase high-performance liquid chromatography to isolate two fractions, PAF and lyso-PAF. In the pouch fluid, however, there was little activity of PAF as examined by the aggregation of guinea pig platelets. The lyso-PAF fraction obtained was acetylated to PAF chemically with pyridine and acetic anhydride. This acetylated lyso-PAF fraction induced the aggregation of guinea pig platelets, which was inhibited dose-dependently by a PAF antagonist, CV-3988. The amount of lyso-PAF in the pouch fluid of the immunized group in the anaphylactic phase was significantly higher than that of the nonimmunized group. When (3H-)PAF was incubated with the supernatant fraction of the pouch fluid it was metabolized into lyso-PAF time-dependently. The significance of the higher level of lyso-PAF in the pouch fluid in the anaphylactic phase of allergic inflammation is discussed.
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000707:Anaphylaxis / Q000503:physiopathology*; D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D005122:Exudates and Transudates / Q000032:analysis*; D007249:Inflammation / Q000503:physiopathology*; D008297:Male; D010742:Phospholipid Ethers; D010972:Platelet Activating Factor / Q000031:analogs & derivatives / Q000032:analysis* / Q000494:pharmacology / Q000502:physiology; D010974:Platelet Aggregation / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D013844:Thiazoles / Q000494:pharmacology
chemical_list: D001095:Arachidonic Acids; C029271:O-deacetyl platelet activating factor; D010742:Phospholipid Ethers; D010972:Platelet Activating Factor; D013844:Thiazoles; D016718:Arachidonic Acid; D000244:Adenosine Diphosphate; C037913:CV 3988