title: Involvement of a guanine-nucleotide-binding protein-mediated mechanism in the enhancement of arachidonic acid liberation by phorbol 12-myristate 13-acetate and Ca2+ in saponin-permeabilized platelets.
abstract: A mechanism by which protein kinase C potentiates arachidonic acid (AA) liberation in rabbit platelets was examined using [3H]AA-labeled, saponin (7 micrograms/ml)-permeabilized rabbit platelets. Pretreatment of the [3H]AA-labeled platelets with 4 beta-phorbol 12-myristate 13-acetate (PMA, 10-40 nM) or 1,2-dioctanoylglycerol (DOG, 20 microM) enhanced [3H]AA liberation induced by an addition of Ca2+ (1 mM) after cell permeabilization, whereas 4 alpha-phorbol 12,13-didecanoate (80 nM) did not exert such an effect. The potentiating effects of PMA and DOG were inhibited by staurosporine (200 nM). PMA (40 nM) also potentiated [3H]AA liberation induced by guanosine 5'-[gamma-thio]triphosphate (GTP gamma S, 100 microM), 5'-guanylyl imidodiphosphate (200 microM) or NaF (20 mM) plus AlCl3 (10 microM) in the presence of Ca2+ (100 microM). The enhancement by PMA of the GTP gamma S-induced AA liberation was also inhibited by staurosporine (200 nM). Furthermore, guanosine 5'-[beta-thio]diphosphate (GDP beta S, 0.5-2 mM) suppressed the PMA (40 nM)- and DOG (20 microM)-enhanced, Ca2+ (1 mM)-dependent [3H]AA liberation. This inhibitory effect of GDP beta S was reversed by a further addition of GTP gamma S (200 microM). However, pertussis toxin (0.2-1 micrograms/ml) had no effect on the PMA-enhanced [3H]AA liberation. These results indicate a possibility that protein kinase C may potentiate AA liberation through a guanine-nucleotide-binding protein-mediated mechanism in saponin-permeabilized rabbit platelets.
authors.affiliation: Department of Biochemistry, Kyoto Pharmaceutical University, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Akiba
authors.forename: T
authors.initials: T
authors.lastname: Sato
authors.forename: T
authors.initials: T
authors.lastname: Fujii
mesh_terms: D000470:Alkaloids / Q000494:pharmacology; D000535:Aluminum / Q000494:pharmacology; D000077410:Aluminum Chloride; D017607:Aluminum Compounds; D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000097:blood*; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism*; D002118:Calcium / Q000494:pharmacology*; D002463:Cell Membrane Permeability / Q000187:drug effects; D002712:Chlorides / Q000494:pharmacology; D004075:Diglycerides / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000502:physiology*; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006153:Guanosine Diphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D006160:Guanosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D006165:Guanylyl Imidodiphosphate / Q000494:pharmacology; D037342:Pertussis Toxin; D011493:Protein Kinase C / Q000097:blood; D011817:Rabbits; D012503:Saponins / Q000494:pharmacology*; D012969:Sodium Fluoride / Q000494:pharmacology; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D013873:Thionucleotides / Q000494:pharmacology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
chemical_list: D000470:Alkaloids; D017607:Aluminum Compounds; D001095:Arachidonic Acids; D002712:Chlorides; D004075:Diglycerides; D012503:Saponins; D013873:Thionucleotides; D010566:Virulence Factors, Bordetella; C044295:1,2-dioctanoylglycerol; D006153:Guanosine Diphosphate; C032829:6-thioguanosine 5'-diphosphate; D016718:Arachidonic Acid; D006165:Guanylyl Imidodiphosphate; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D000077410:Aluminum Chloride; D006160:Guanosine Triphosphate; D012969:Sodium Fluoride; D000535:Aluminum; D037342:Pertussis Toxin; D011493:Protein Kinase C; D019204:GTP-Binding Proteins; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium