Mechanism of Polymorphonuclear Leukocyte Activation by Myristate. Involvement ofCalcium Ion and Protein Kinase C
1987 年 12 巻 4 号 p. 357-367
詳細
1987 年 12 巻 4 号 p. 357-367
The stimulative effects of myristate on the superoxide gene-ation and depolarization of membrane potential of polymorphonuclear leukocytes (PMN) are particularly strong, yet myristate does not affect the intracellular free Ca2+ level ([Ca2+]i) in the presence of 1 μM free calcium in calcium-EGTA buffer. The half maximum concentration of myristate was 10μM. Myristate inhibited the transitory changes in [Ca2+]i induced by formylmethionyl-leucyl-phenylalanine (FMLP), but stimulated further the FMLP-induced superoxide generation; these effects are similar to those of phorbol myristate acetate (PMA). The myristate-induced superoxide gener-ation was partially inhibited by H-7, a specific inhibitor of protein kinase C. Myristate stimulated the activity of Ca2+-and phospholipid-dependent protein kinase (protein kinase C) in a concentration-dependent manner in the presence of 10-6 M Ca2+. The Ka was 100 μM. These results suggested that there is no relation between the superoxide generation and the [Ca2+]i change in PMNs and that the effects of myristate are similar to those of PMA against PMN.
