Effect of ethanol on ATP-induced phospholipases C and D and serine base exchange in glioma C6 cells.
The effect of extracellular ATP, a nucleotide receptor agonist in the central nervous system, was investigated in glioma C6 cells on the intracellular Ca2+ level and the formation of phosphatidylethanol and phosphatidic acid in the presence and absence of ethanol (150 mM). In the cells prelabeled with [14C]palmitic acid, 100 microM ATP induced both the hydrolysis and the transphosphatidylation reactions leading to the formation of [14C]phosphatidic acid; addition of ethanol generated [14C]phosphatidylethanol. However, ATP-mediated increase in the level of [14C]phosphatidic acid was not inhibited by ethanol. Furthermore, ethanol augmented ATP-induced transient and sustained increase in the intracellular Ca2+ concentration, whereas ethanol alone did not produce any change in the intracellular Ca2+ level. These results indicate that in glioma C6 cells, ATP induces activation of polyphosphoinositide-specific phospholipase C and phospholipase D and that ethanol enhances this effect. In the present investigation we have also shown that long-term (2 days) ethanol treatment, at concentration relevant to chronic alcoholism (100 mM), decreased the incorporation of [14C]serine into phosphatidylserine. Since the effect of ethanol on ATP-induced activities of phospholipase C and phospholipase D and on serine base-exchange in glioma C6 cells differs significantly from that in cultured neuronal cells, these results may contribute to a better understanding of the mechanisms of ethanol action in cells of glial origin.
Wójcik
M
M
Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland.
Dygas
A
A
Bobeszko
M
M
Czajkowski
R
R
Barańska
J
J
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D000431:Ethanol / Q000494:pharmacology*; D005910:Glioma / Q000378:metabolism*; D020404:Glycerophospholipids / Q000096:biosynthesis; D006868:Hydrolysis; D007700:Kinetics; D019308:Palmitic Acid / Q000378:metabolism; D010712:Phosphatidic Acids / Q000096:biosynthesis; D010718:Phosphatidylserines / Q000378:metabolism; D010739:Phospholipase D / Q000378:metabolism*; D012694:Serine / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D010738:Type C Phospholipases / Q000378:metabolism*
D020404:Glycerophospholipids; D010712:Phosphatidic Acids; D010718:Phosphatidylserines; C051521:phosphatidylethanol; D019308:Palmitic Acid; D000431:Ethanol; D012694:Serine; D000255:Adenosine Triphosphate; D010738:Type C Phospholipases; D010739:Phospholipase D; D002118:Calcium