CHANGES IN PHOSPHATIDYLINOSITOL-4,5-BISPHOSPHATE 10 SECONDS AFTER STIMULATION OF WASHED RABBIT PLATELETS WITH ADP

  • 1 January 1982
    • journal article
    • research article
    • Vol. 60  (6) , 1247-1251
Abstract
ADP induced aggregation of rabbit platelets, without the release reaction, causes a significant decrease (7%) in the amount of phosphatidylinositol-4,5-bisphosphate (PIP2) at 10 and 60 s (11%). In platelets prelabeled with 32P-phosphate, this decrease in PIP2 is associated with a decrease in PIP2 radioactivity, which is significant at 60 s. The decrease in PIP2 is sufficient to mobilize .apprx. 0.18 nmol Ca2+/109 platelets. In view of the key role of Ca2+ in ADP-induced platelet shape change and aggregation, changes in PIP2 apparently can be a source of Ca for cellular responses to agonists.