Enhancement of arachidonic acid liberation by protein kinase C activator is partially dependent on extracellular Na+ in rabbit platelets.
In [3H]arachidonic acid-labeled rabbit platelets, pretreatment with phorbol 12-myristate 13-acetate (20 nM) or dioctanoylglycerol (20 microM) enhanced [3H]arachidonic acid liberation induced by low concentration of A23187 (150 nM). When extracellular Na+ was replaced with N-methyl-D-glucamine, the enhancement is reduced by about 50%. Similar synergistic enhancement of the liberation was obtained by using monensin (2-10 microM) or NH4Cl (5-20 mM) in place of protein kinase C activator in combination with A23187. The guanosine 5'-O-[3-thiotriphosphate] (100 microM)-induced liberation was also enhanced by a rise of extracellular pH (pH 7.0-7.8) in saponin-permeabilized platelets. These results suggest that the enhancement of arachidonic acid liberation by protein kinase C may partially be mediated by intracellular alkalinization in rabbit platelets.
Akiba
S
S
Department of Biochemistry, Kyoto Pharmaceutical University, Japan.
Sato
T
T
Fujii
T
T
D000818:Animals; D016718:Arachidonic Acid; D001095:Arachidonic Acids / Q000378:metabolism*; D001792:Blood Platelets / Q000378:metabolism*; D000001:Calcimycin / Q000494:pharmacology; D004075:Diglycerides / Q000494:pharmacology; D004357:Drug Synergism; D004789:Enzyme Activation / Q000187:drug effects; D006160:Guanosine Triphosphate / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007425:Intracellular Membranes / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism*; D011817:Rabbits; D012964:Sodium / Q000378:metabolism* / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D001095:Arachidonic Acids; D004075:Diglycerides; D016718:Arachidonic Acid; D000001:Calcimycin; D006160:Guanosine Triphosphate; D012964:Sodium; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate