Ethanol-induced increases in [Ca2+]i and inositol (1,4,5) triphosphate in rat hepatocytes.
Rat hepatocytes were studied for [Ca2+]i with Fura-2 at the single cell level using a microfluorometer-imaging system which showed that both the number of cells elevating [Ca2+]i and the magnitude of [Ca2+]i increase were directly dependent upon ethanol concentration between 50 mM and 1 M. Peak [Ca2+]i increases ranged from 27 nM with 50 mM ethanol to 57 nM after 1 M ethanol. Ethanol appeared to initiate calcium release from intracellular stores and caused a dose dependent production of inositol(1,4,5) triphosphate (Ins(1,4,5)P3) in hepatocytes. Low concentrations of ethanol (50-100 mM) did not significantly raise Ins(1,4,5)P3 although 300 mM-1 M increased Ins(1,4,5)P3 comparable to that found with vasopressin (5 nM). In summary, physiologic amounts of ethanol raise [Ca2+]i in rat hepatocytes, although at lower levels (50-100 mM) the changes may or may not be related to an Ins(1,4,5)P3 pathway.
Reinlib
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L
Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205.
Akinshola
E
E
Potter
J J
JJ
Mezey
E
E
D000818:Animals; D001667:Binding, Competitive; D002118:Calcium / Q000378:metabolism*; D003592:Cytophotometry; D000431:Ethanol / Q000494:pharmacology*; D016257:Fura-2 / Q000494:pharmacology*; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism*; D008099:Liver / Q000166:cytology / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D010738:Type C Phospholipases / Q000378:metabolism*; D014667:Vasopressins / Q000494:pharmacology
D014667:Vasopressins; D000431:Ethanol; D015544:Inositol 1,4,5-Trisphosphate; D010738:Type C Phospholipases; D002118:Calcium; D016257:Fura-2