title: Activation of protein kinase C inhibits sodium fluoride-induced elevation of human platelet cytosolic free calcium and thromboxane B2 generation.
abstract: Addition of NaF to washed platelets produces a dose-dependent and transient elevation of the intracellular free calcium concentration ([Ca++]i), thromboxane B2 (TxB2) generation and dense granule release, all of which are significantly inhibited when the extracellular calcium concentration ([Ca++]e) is reduced with EGTA. Inhibition of platelet cyclo-oxygenase by acetylsalicylic acid (ASA) does not affect NaF-induced elevation of [Ca++]i and dense granule release in the presence of 1 mM [Ca++]e. Pre-incubation of the platelets with the phorbol ester TPA produces a marked inhibition of NaF-induced elevation of [Ca++]i and TxB2 generation without affecting dense granule release. Thus, NaF may have more than one site of action. Pretreatment of the platelets with the selective protein kinase C inhibitor H7 prevents TPA induced inhibition of NaF mediated rise in [Ca++]i and TxB2 generation. Thus we propose that NaF induced calcium mobilisation is analogous to receptor-operated calcium mobilisation in platelets, as it is readily inhibited by protein kinase C activation or by the reduction of [Ca++]e and is independent of platelet cyclo-oxygenase activity.
mesh_terms: D001241:Aspirin / Q000494:pharmacology; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism; D002118:Calcium / Q000097:blood*; D002712:Chlorides; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004533:Egtazic Acid / Q000494:pharmacology; D004789:Enzyme Activation; D006801:Humans; D008345:Manganese / Q000494:pharmacology; D017895:Manganese Compounds; D011493:Protein Kinase C / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism; D012969:Sodium Fluoride / Q000494:pharmacology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013929:Thromboxane B2 / Q000096:biosynthesis*
chemical_list: D002712:Chlorides; D017895:Manganese Compounds; D012701:Serotonin; D008345:Manganese; D004533:Egtazic Acid; D013929:Thromboxane B2; D012969:Sodium Fluoride; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate; C025340:manganese chloride; D001241:Aspirin; D002118:Calcium