Modulation of superoxide anion generation by manoalide, arachidonic acid and staurosporine in liver infiltrated neutrophils in a rat model of endotoxemia

J Pharmacol Exp Ther. 1993 Oct;267(1):400-9.


Early accumulation of polymorphonuclear leukocytes (PMN) in the liver after in vivo exposure to Escherichia coli lipopolysaccharide (LPS) and concomitant in vitro phorbol myristate acetate (PMA)-stimulated superoxide anion (O2-) generation has recently been described in a rat model of endotoxemia. The purpose of this investigation was to study the role of phospholipase A2 (PLA2), arachidonic acid (AA), its metabolites, and protein kinase C (PKC) in the mechanism of PMA-stimulated O2- generation of liver infiltrated PMN as compared to circulating blood PMN. Rat PMN were isolated after a 1.5-h infusion of saline or LPS from the blood (SAL-PMN) or the liver (LPS-PMN), respectively. The following results were observed in both SAL-PMN and LPS-PMN: 1) Inhibitors of cyclooxygenase (indomethacin) and 5-lipoxygenase [eicosatetraynoic acid, WY 50,295 tromethamine and VZ 65, 4-(11-hydroxy-1,9-undecadiin)-brenzcatechin] pathways did not inhibit O2- generation; 2) the potent marine PLA2 inhibitor Manoalide inhibited O2- generation in a dose-dependent manner (IC50 = 0.5 microM); 3) exogenously added AA enhanced PMA-stimulated O2- generation in a time- and dose-dependent manner and partially reversed the effect of Manoalide in LPS-PMN; 4) staurosporine, a putative PKC inhibitor, blocked PMA-stimulated O2- generation completely in the absence of AA and 79% in the presence of AA. It was concluded that LPS-induced liver sequestration of PMN does not alter the role PLA2, AA and PKC play in PMA-stimulated O2- generation. These findings should have implications on the design of novel therapeutic approaches for the modulation of O2- release in the pathogenesis of LPS hepatotoxicity.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Alkaloids / pharmacology*
  • Animals
  • Arachidonic Acid / pharmacology*
  • Arachidonic Acid / physiology
  • Carbon Monoxide / pharmacology
  • Endotoxins / toxicity*
  • Fatty Acids, Nonesterified / physiology
  • Kupffer Cells / physiology
  • Lipoxygenase Inhibitors
  • Liver / cytology
  • Liver / metabolism*
  • Male
  • Neutrophils / metabolism*
  • Phospholipases A / physiology
  • Phospholipases A2
  • Protein Kinase C / physiology
  • Rats
  • Rats, Sprague-Dawley
  • Staurosporine
  • Superoxides / metabolism*
  • Terpenes / pharmacology*
  • Tetradecanoylphorbol Acetate / pharmacology


  • Alkaloids
  • Endotoxins
  • Fatty Acids, Nonesterified
  • Lipoxygenase Inhibitors
  • Terpenes
  • Superoxides
  • Arachidonic Acid
  • Carbon Monoxide
  • manoalide
  • Protein Kinase C
  • Phospholipases A
  • Phospholipases A2
  • Staurosporine
  • Tetradecanoylphorbol Acetate