Cytosolic free magnesium, ATP and blebbing during chemical hypoxia in cultured rat hepatocytes.
Cytosolic free Mg2+ concentration was determined in 1-day cultured rat hepatocytes using Multiparameter Digitized Video Microscopy (MDVM) of the fluorescent probe, mag-fura-2. Chemical hypoxia with KCN (5 mM) and iodoacetate (1 mM), a model which mimics the ATP depletion and reductive stress of hypoxia, caused a rapid increase of free Mg2+ from 1.1 +/- 0.2 to 1.6 +/- 0.2 mM within 4 min. Concurrently, numerous small plasma membrane blebs formed and ATP levels dropped from 13.24 to 1.32 nmol/10(6) cells. Removal of KCN and iodoacetate resulted in recovery of ATP to 60-70% of pre-exposure levels, a concomitant decrease in cytosolic free Mg2+ back toward basal levels, and reversal of blebbing (bleb resorption). These results indicate that changes of cytosolic free Mg2+ inversely reflect changes of ATP in a model of hypoxia and reoxygenation. Bleb formation and resorption were dependent on the fall and rise of ATP.
Harman
A W
AW
Department of Cell Biology & Anatomy, School of Medicine, University of North Carolina, Chapel Hill 27599-7090.
Nieminen
A L
AL
Lemasters
J J
JJ
Herman
B
B
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D003600:Cytosol / Q000378:metabolism*; D005456:Fluorescent Dyes; D008099:Liver / Q000166:cytology / Q000293:injuries* / Q000378:metabolism; D008274:Magnesium / Q000378:metabolism*; D008297:Male; D010100:Oxygen / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D014741:Video Recording
D005456:Fluorescent Dyes; D000255:Adenosine Triphosphate; D008274:Magnesium; D010100:Oxygen