4-Hydroxynonenal triggers Ca2+ influx in isolated rat hepatocytes.
Addition of micromolar concentrations of 4-hydroxynonenal (4-HNE), a reactive end-product of lipid peroxidation, to isolated rat hepatocytes was found to cause an early and transient increase in cytosolic Ca2+ concentration followed by a more pronounced and progressive elevation. Such a late effect of 4-HNE was prevented by chelation of extracellular Ca2+ with EGTA or by the addition of GdCl3, which is known to block the activity of store operated Ca2+ channels in the hepatocyte plasma membrane. Moreover, the preincubation of isolated hepatocytes with the phospholipase C inhibitor U73122 resulted in a complete inhibition of both the early increase of cytosolic Ca2+ and the subsequent Ca2+ inflow. When 4-HNE was added to the hepatocytes 5 min after the emptying of intracellular Ca2+ pools by thapsigargin, the aldehyde caused a further increase in the accumulation of Ca2+ which was prevented in the presence of GdCl3. Taken together these results indicate that in hepatocytes 4-HNE causes Ca2+ inflow across GdCl3-sensitive Ca2+ channels. The mechanism responsible for such an effect is triggered by the emptying of intracellular Ca2+ pools likely resulting from 4-HNE mediated stimulation of phospholypase C, but 4-HNE also appears to interfere with the channel protein(s) or with the mechanism(s) regulating capacitative Ca2+ inflow.
Carini
R
R
Department of Medical Sciences, University of Torino, Novara, Italy.
Bellomo
G
G
Paradisi
L
L
Dianzani
M U
MU
Albano
E
E
D000447:Aldehydes / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000187:drug effects; D002478:Cells, Cultured; D015640:Ion Channel Gating / Q000187:drug effects; D008054:Lipid Peroxides / Q000494:pharmacology*; D008099:Liver / Q000378:metabolism*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013729:Terpenes / Q000494:pharmacology; D019284:Thapsigargin
D000447:Aldehydes; D015220:Calcium Channels; D008054:Lipid Peroxides; D013729:Terpenes; D019284:Thapsigargin; C027576:4-hydroxy-2-nonenal; D002118:Calcium