Control of mitochondrial matrix calcium: studies using fluo-3 as a fluorescent calcium indicator.
Fluo-3, a fluorescent Ca2+ indicator, is sequestered by isolated rat liver mitochondria and is an effective probe for evaluating the concentration and kinetics of change of mitochondrial matrix ionized calcium ([Ca2+]m) under a variety of conditions. At the wavelengths employed, there is no significant interference by auto-fluorescence. There is an insignificant release of the indicator over four hours and the loading and presence of fluo-3 has no effect on respiratory rate or oxidative phosphorylation. The [Ca2+]m steady state can be altered by the assay conditions, i.e. the presence of extra-mitochondrial Ca2+, Mg2+ phosphate and respiratory inhibitors. The total matrix ionized calcium represents a small percent (less than 0.01%) of the total mitochondrial calcium.
Saavedra-Molina
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A
Department of Biological Chemistry, Hahnemann University School of Medicine, Philadelphia, PA 19102.
Uribe
S
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Devlin
T M
TM
D000814:Aniline Compounds; D000818:Animals; D000838:Anions; D002118:Calcium / Q000378:metabolism*; D005456:Fluorescent Dyes; D008297:Male; D008930:Mitochondria, Liver / Q000378:metabolism*; D010085:Oxidative Phosphorylation; D010101:Oxygen Consumption; D051381:Rats; D011919:Rats, Inbred Strains; D014966:Xanthenes
D000814:Aniline Compounds; D000838:Anions; D005456:Fluorescent Dyes; D014966:Xanthenes; C059715:Fluo-3; D002118:Calcium