lithium-chloride and aluminum-fluoride

Hydrogen peroxide stimulates apoptosis of zymosan-activated rat peritoneal macrophages. Phosphoinositide cycle modifiers enhance the proapoptotic effect of H(2)O(2) in a concentration of 1 mM and necrosis-stimulating effect of H(2)O(2) in a concentration of 10 mM. Disorders in phosphoinositide metabolism and impaired reaction of the cell to proinflammatory agents are the cause of programmed cell death. Rejection of defective cells can be realized via variation of H(2)O(2) concentration.

Topics: Aluminum Compounds; Animals; Antipsychotic Agents; Apoptosis; Chlorpromazine; Fluorescent Dyes; Fluorides; Hydrogen Peroxide; Lithium Chloride; Macrophages, Peritoneal; Male; Oxidants; Phosphatidylinositols; Protease Inhibitors; Rats; Rats, Wistar; Tosyl Compounds; Zymosan

Phospholipase A2 (PLA2) is an enzyme which participates in signalling mechanisms cleaving arachidonate from sn-2 position of glycerophospholipids. In this study we have verified the existence of a PLA2-like activity in the free living protozoan, Tetrahymena pyriformis GL. This activity is Ca(2+)-independent, EDTA (10 mM) has no effect on its activity. Quinacrine (0.1 mM) and 4-bromophenacyl bromide (BPB; 0.1 mM) inhibited, melittin (20 micrograms/ml) significantly stimulated the PLA2 activity and the release of free arachidonic acid (AA) from 1-acyl 2-14C-arachidonyl-3-phosphatidylethanolamine substrate. Melittin stimulated PLA2 hyperactivity is CA(2+)-dependent. There was no considerable alteration in the PLA2 activity by stimulation of the activity by tyrosine kinase (with vanadate, H2O2), phospholipase C (PLC) (with phorbol 12, 13-dibutyrate) or G-proteins (with NaF, AlF4), thus in Tetrahymena PLA2 activity seems to be independent of these--in Tetrahymena (also functioning)--signalling pathways. Treatment with quinacrine and BPB leads to decreased synthesis and disturbed breakdown of phospholipids and phosphoinositides. These findings suggest that PLA2 activity is in connection with the phospholipid metabolism of Tetrahymena.

Topics: Acetophenones; Aluminum Compounds; Animals; Arachidonic Acid; Calcium; Enzyme Activation; Enzyme Inhibitors; Fluorides; Hydrogen Peroxide; Inositol; Lithium Chloride; Melitten; Phorbol 12,13-Dibutyrate; Phosphatidylinositols; Phospholipases A; Phospholipases A2; Phospholipids; Protein-Tyrosine Kinases; Quinacrine; Signal Transduction; Sodium Fluoride; Tetrahymena pyriformis; Vanadates

Topics: Aluminum; Aluminum Compounds; Animals; Biological Transport, Active; Calcium; Cell Membrane; Chlorides; Fluorides; GTP-Binding Proteins; Inositol Phosphates; Kinetics; Lithium; Lithium Chloride; Melatonin; Pituitary Gland, Anterior; Sheep; Signal Transduction; Sodium Fluoride