title: Regulation by protein kinase C of platelet-activating factor- and thapsigargin-induced calcium entry in rabbit neutrophils.
abstract: 12-O-Tetradecanoylphorbol-13-acetate (TPA) time-dependently inhibited the platelet-activating factor (PAF)-induced rise in cytosolic free calcium concentration ([Ca2+]i) in rabbit neutrophils, whereas staurosporine significantly enhanced it. Inositol 1,4,5-trisphosphate (IP3) induced Ca2+ release in digitonin-permeabilized cells but not in PAF-pretreated permeabilized cells. IP3-induced Ca2+ release was not affected by protein kinase C activators or inhibitors. In the cells pretreated with PAF and thapsigargin in Ca(2+)-deficient medium, stimulated Ca2+ entry was evoked by the subsequent addition of CaCl2. TPA inhibited the Ca2+ entry induced by PAF and thapsigargin in a staurosporine-reversible manner but not thapsigargin-induced [Ca2+]i elevation. These results suggest that protein kinase C negatively regulates PAF- and thapsigargin-induced rise in [Ca2+]i possibly by inhibiting Ca2+ store depletion-induced Ca2+ entry.
authors.affiliation: Department of Endodontology and Periodontology, Hiroshima University School of Dentistry, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Shibata
authors.forename: S
authors.initials: S
authors.lastname: Kitayama
authors.forename: K
authors.initials: K
authors.lastname: Morita
authors.forename: M
authors.initials: M
authors.lastname: Shirakawa
authors.forename: H
authors.initials: H
authors.lastname: Okamoto
authors.forename: T
authors.initials: T
authors.lastname: Dohi
mesh_terms: D000470:Alkaloids / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002122:Calcium Chloride / Q000494:pharmacology; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors*; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D004594:Electrophysiology; D004789:Enzyme Activation / Q000187:drug effects; D015544:Inositol 1,4,5-Trisphosphate / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D010972:Platelet Activating Factor / Q000494:pharmacology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011817:Rabbits; D013050:Spectrometry, Fluorescence; D019311:Staurosporine; D013729:Terpenes / Q000494:pharmacology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D019284:Thapsigargin
chemical_list: D000470:Alkaloids; D010972:Platelet Activating Factor; D013729:Terpenes; D019284:Thapsigargin; D015544:Inositol 1,4,5-Trisphosphate; D011493:Protein Kinase C; D000252:Calcium-Transporting ATPases; D019311:Staurosporine; D002122:Calcium Chloride; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium