Laser-induced stimulation of thromboxane B2 synthesis in human blood platelets: role of superoxide radicals.
Exposure of platelet-rich plasma to laser radiation at 3.5 W for 30 seconds reduced the threshold concentrations of adenosine diphosphate and L-epinephrine needed from complete platelet aggregation by 20% to 60% and by 30% to 50%, respectively. The irradiation of platelet-rich plasma with laser also increased the basal level of thromboxane A2 from < 0.5 pmol/10(8) platelets for each second of exposure. In contrast, the exposure of gel-filtered platelets to laser produced no effect on the prostanoid formation. However, the addition of laser-exposed platelet-free plasma to gel-filtered platelets stimulated the synthesis of thromboxane A2 in these cells. The effect of laser was completely blocked by adding superoxide dismutase or catalase to the platelet-rich plasma, indicating that the radiation-induced stimulation of thromboxane A2 production was mediated through the generation of superoxide radicals. Electron microscopic studies indicated that the laser-induced stimulation of thromboxane A2 production in platelet can occur without any noticeable damage in the cellular structure.
Arora
R R
RR
Department of Medicine, Columbia University College of Physicians and Surgeons, New York, NY.
Mueller
H S
HS
Sinha
A K
AK
D001792:Blood Platelets / Q000378:metabolism / Q000528:radiation effects* / Q000648:ultrastructure; D002374:Catalase / Q000494:pharmacology; D005609:Free Radicals; D006801:Humans; D007834:Lasers; D008854:Microscopy, Electron; D010974:Platelet Aggregation / Q000528:radiation effects; D013482:Superoxide Dismutase / Q000494:pharmacology; D013481:Superoxides / Q000097:blood; D013928:Thromboxane A2 / Q000096:biosynthesis*; D013929:Thromboxane B2 / Q000096:biosynthesis*
D005609:Free Radicals; D013481:Superoxides; D013929:Thromboxane B2; D013928:Thromboxane A2; D002374:Catalase; D013482:Superoxide Dismutase