Premium
Mitochondrial Ca 2+ Flux through Na + /Ca 2+ Exchange
Author(s) -
KIM BONGJU,
MATSUOKA SATOSHI
Publication year - 2007
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1196/annals.1387.027
Subject(s) - mitochondrion , chemistry , cytoplasm , biophysics , sodium calcium exchanger , ion exchange , cytosol , calcium , microbiology and biotechnology , biochemistry , biology , ion , intracellular , enzyme , organic chemistry
To clarify the property of mitochondrial Na + /Ca 2+ exchange in situ , we measured mitochondrial Ca 2+ using Rhod‐2 in permeabilized rat ventricular myocytes. Cytoplasmic 300 nM Ca 2+ (Ca 2+ c ) augmented the Rhod‐2 intensity by ∼ninefolds without cytoplasmic Na + (Na + c ). Increasing Na + c attenuated the maximum level of Rhod‐2 fluorescence, probably due to the activation of forward mode of mitochondrial Na + /Ca 2+ exchange. The Rhod‐2 intensity decayed upon removing Ca 2+ c . The decay was dependent on Na + c (K 1/2 =∼1 mM) and largely abolished by an inhibitor of mitochondrial Na + /Ca 2+ exchange, CGP‐37157. It was suggested that Na + binding to the mitochondrial Na + /Ca 2+ exchange is saturated in the physiological concentration of Na + c .