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Mitochondrial free calcium transients during excitation‐contraction coupling in rabbit cardiac myocytes
Author(s) -
Chacon Enrique,
Lemasters John J,
Ohata Hisayuki,
Harper Ian S,
Trollinger Donna R,
Herman Brian
Publication year - 1996
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(96)00138-x
Subject(s) - cytosol , mitochondrion , myocyte , biophysics , contraction (grammar) , microbiology and biotechnology , chemistry , calcium , adenosine triphosphate , biology , biochemistry , endocrinology , enzyme , organic chemistry
Mitochondrial free Ca 2+ may regulate mitochondrial ATP production during cardiac exercise. Here, using laser scanning confocal microscopy of adult rabbit cardiac myocytes co‐loaded with Fluo‐3 to measure free Ca 2+ and tetramethylrhodamine methylester to identify mitochondria, we measured cytosolic and mitochondrial Ca 2+ transients during the contractile cycle. In resting cells, cytosolic and mitochondrial Fluo‐3 signals were similar. During electrical pacing, transients of Fluo‐3 fluorescence occurred in both the cytosolic and mitochondrial compartments. Both the mitochondrial and the cytosolic transients were potentiated by isoproterenol. These experiments show directly that mitochondrial free Ca 2+ rises and falls during excitation‐contraction coupling in cardiac myocytes and that changes of mitochondrial Ca 2+ are kinetically component to regulate mitochondrial metabolism on a beat‐to‐beat basis.