title: Amplification of platelet response during acute inflammation in rats.
abstract: Enhanced aggregation of platelets was observed in platelet-rich plasma, but not in washed platelet suspension (WPS), during acute inflammation in rats. Incubation of WPS with inflammatory plasma increased the aggregatory response to ADP, but the plasma itself did not cause aggregation of platelets. It potentiated the aggregatory response of normal platelets, when platelets were stimulated with arachidonic acid, thrombin, calcium ionophore A23187 or phorbol-12-myristate-13-acetate. Pretreatment of rats with indomethacin (10 mg/kg) did not prevent the increased aggregation response of platelets due to inflammation. This response was not due to any of the biogenic amines nor was it due to platelet factor 4. The activity of the inflammatory plasma was reduced when it was incubated with phospholipase A2, indicating the involvement of platelet-activating factor (PAF). The activity was present both in the lipid and the protein fraction of the inflammatory plasma. The results indicate that a substance(s) released in the circulation during inflammation renders the platelets hyperactive. This substance appears to be a protein which is present in the inflammatory plasma and acts together with PAF to cause increased aggregation of platelets.
authors.affiliation: Division of Pharmacology, Central Drug Research Institute, Lucknow, India.
authors.forename: R
authors.initials: R
authors.lastname: Srivastava
authors.forename: R C
authors.initials: RC
authors.lastname: Srimal
mesh_terms: D000208:Acute Disease; D000818:Animals; D004533:Egtazic Acid / Q000494:pharmacology; D005707:Gallic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D006493:Heparin / Q000494:pharmacology; D007249:Inflammation / Q000097:blood*; D008297:Male; D010741:Phospholipases A / Q000494:pharmacology; D054467:Phospholipases A2; D010972:Platelet Activating Factor / Q000502:physiology; D010974:Platelet Aggregation / Q000187:drug effects*; D010978:Platelet Factor 4 / Q000502:physiology; D051381:Rats
chemical_list: D010972:Platelet Activating Factor; D010978:Platelet Factor 4; D004533:Egtazic Acid; C006014:8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate; D005707:Gallic Acid; D006493:Heparin; D010741:Phospholipases A; D054467:Phospholipases A2