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.
Department of Medicine, Columbia University College of Physicians and Surgeons, New York, NY.
R R
RR
Arora
H S
HS
Mueller
A K
AK
Sinha
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