Superoxide anions enhance platelet adhesion and aggregation.
1. Superoxide dismutase (SOD, 60 u ml-1) or ferricytochrome c (70 microM) significantly inhibited thrombin-stimulated platelet adhesion to gelatin-coated plastic, whereas catalase (1000 u ml-1) or mannitol (1 mM) had no effect. 2. The platelet aggregation induced by low concentrations of thrombin (causing less than 45% maximal change in light transmission) was inhibited by SOD. Catalase or mannitol had no effect on platelet aggregation. 3. Pyrogallol (an O2- generator) enhanced both platelet adhesion to gelatin-coated plastic and platelet aggregation induced by thrombin; this enhancement was neutralized by SOD. 4. These results indicate that O2- increase both platelet adhesion and aggregation, whereas other free radicals such as hydrogen peroxide or hydroxyl radicals are not involved.
Salvemini
D
D
William Harvey Research Institute, St Bartholomew's Hospital Medical College, London.
de Nucci
G
G
Sneddon
J M
JM
Vane
J R
JR
D000225:Adenine / Q000378:metabolism; D002374:Catalase / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D008353:Mannitol / Q000494:pharmacology; D010973:Platelet Adhesiveness / Q000187:drug effects*; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors; D011748:Pyrogallol / Q000494:pharmacology; D013482:Superoxide Dismutase / Q000494:pharmacology; D013481:Superoxides / Q000494:pharmacology*; D013917:Thrombin / Q000494:pharmacology
D010975:Platelet Aggregation Inhibitors; D011748:Pyrogallol; D013481:Superoxides; D008353:Mannitol; D002374:Catalase; D013482:Superoxide Dismutase; D013917:Thrombin; D000225:Adenine