Sub-second oscillations of inositol 1,4,5-trisphosphate and inositol 1,3,4,5-tetrakisphosphate during platelet activation by ADP and thrombin: lack of correlation with calcium kinetics.
The hypothesis that ADP and thrombin liberate Ins(1,4,5)P3 in blood platelets, with kinetics consistent for releasing Ca2+ within 2s, was tested by quenched-flow techniques. Both agonists stimulated transient and equal synthesis of Ins(1,4,5)P3 and Ins(1,3,4,5)P4 near 200 ms and later short-lived peaks, which were not correlated with the slower steady increase in intracellular [Ca2+] between 0.5 to 2 s detected by Indo-1. Shear forces alone caused transient liberation of these inositol phosphates within 0.5 s and up to 4 s, yet failed to increase intracellular [Ca2+].
Raha
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Department of Biochemistry, University of Virginia Health Sciences Center, Charlottesville 22908.
Jones
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Gear
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D000244:Adenosine Diphosphate / Q000494:pharmacology*; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D002118:Calcium / Q000097:blood*; D006801:Humans; D066298:In Vitro Techniques; D015544:Inositol 1,4,5-Trisphosphate / Q000097:blood* / Q000302:isolation & purification; D007295:Inositol Phosphates / Q000097:blood* / Q000302:isolation & purification; D007700:Kinetics; D015539:Platelet Activation; D010974:Platelet Aggregation / Q000187:drug effects; D013314:Stress, Mechanical; D013917:Thrombin / Q000494:pharmacology*; D013997:Time Factors
D007295:Inositol Phosphates; C081655:inositol-1,3,4,5-tetrakisphosphate; D000244:Adenosine Diphosphate; D015544:Inositol 1,4,5-Trisphosphate; D013917:Thrombin; D002118:Calcium