title: Reversal by protein kinase C inhibitor of suppressive actions of phorbol-12-myristate-13-acetate on polyphosphoinositide metabolism and cytosolic Ca2+ mobilization in thrombin-stimulated human platelets.
abstract: In the presence of 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7), a potent inhibitor of protein kinase C in vitro, phorbol-12-myristate-13-acetate (PMA) did not suppress the thrombin-induced increase of cytosolic Ca2+ concentration in human platelets. The H-7 reversal of the inhibitory action of PMA was also observed in thrombin-induced polyphosphoinositide breakdown by phospholipase C. These results provide additional support to the developing theory that the inhibition of PMA on Ca2+ mobilization and phosphoinositide turnover may be mediated by protein kinase C activation.
mesh_terms: D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism*; D002118:Calcium / Q000097:blood; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D066298:In Vitro Techniques; D007546:Isoquinolines / Q000494:pharmacology*; D010704:Phorbols / Q000494:pharmacology*; D010716:Phosphatidylinositols / Q000097:blood / Q000378:metabolism*; D010750:Phosphoproteins / Q000097:blood / Q000378:metabolism; D010879:Piperazines / Q000494:pharmacology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors* / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D013917:Thrombin / Q000494:pharmacology
chemical_list: D007546:Isoquinolines; D010704:Phorbols; D010716:Phosphatidylinositols; D010750:Phosphoproteins; D010879:Piperazines; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D011493:Protein Kinase C; D013917:Thrombin; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium