Influence of calcium on arachidonic acid mobilization by murine resident peritoneal macrophages

Arch Biochem Biophys. 1995 Nov 10;323(2):251-7. doi: 10.1006/abbi.1995.9967.

Abstract

Stimulation of resident peritoneal macrophages resulted in release of arachidonic acid (AA) from phospholipids. This AA release is believed to occur as a result of the activation of phospholipases, usually by a phospholipase A2 (PLA2). The purpose of this study was to elucidate the role of cytosolic calcium ion concentration ([Ca2+]i) in the modulation of [3H]AA mobilization in peritoneal macrophages. [3H]AA release induced by ionophore A23187, opsonized zymosan, or 4 beta-phorbol 12-myristate acetate (PMA) occurred in the absence of extracellular calcium. Studies in fura-2/AM-loaded cells showed that zymosan and PMA did not increase [Ca2+]i significantly, whereas A23187 induced PLA2 activity translocation up to plasmatic membrane. Thapsigargin, an inhibitor of endomembrane Ca(2+)-ATPase, induced a rise in [Ca2+]i when cells were incubated in a Ca2+ medium. However, thapsigargin was not an effective stimulator of the translocation of PLA2 activity and [3H]AA release. These data indicate that changes in [Ca2+]i were not sufficient to elicit [3H]AA mobilization; this process seems tightly modulated by phosphorylation-dependent mechanisms in the presence of low [Ca2+]i.

MeSH terms

  • Animals
  • Arachidonic Acid / metabolism*
  • Calcimycin / pharmacology
  • Calcium / metabolism*
  • Calcium Channel Blockers / pharmacology*
  • Calcium-Transporting ATPases / antagonists & inhibitors
  • Cell Membrane / enzymology
  • Cytosol / enzymology
  • Enzyme Activation / drug effects
  • Enzyme Inhibitors / pharmacology
  • Ionophores / pharmacology
  • Macrophages, Peritoneal / metabolism*
  • Male
  • Mice
  • Phospholipases A / metabolism*
  • Phospholipases A2
  • Protein Kinase C / metabolism
  • Terpenes / pharmacology
  • Tetradecanoylphorbol Acetate / pharmacology
  • Thapsigargin

Substances

  • Calcium Channel Blockers
  • Enzyme Inhibitors
  • Ionophores
  • Terpenes
  • Arachidonic Acid
  • Calcimycin
  • Thapsigargin
  • Protein Kinase C
  • Phospholipases A
  • Phospholipases A2
  • Calcium-Transporting ATPases
  • Tetradecanoylphorbol Acetate
  • Calcium