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Copyright © 1997 by the American Physiological Society.
AJP - Heart and Circulatory Physiology, Vol 272, Issue 5 2095-H2106, Copyright © 1997 by American Physiological Society
Oxidants increase intracellular free Zn2+ concentration in rabbit ventricular myocytes
B. Turan, H. Fliss and M. Desilets
Oxidative stress may alter cardiac function by affecting intracellular free Zn2+ concentrations ([Zn2+]i). Rabbit ventricular myocytes loaded with fura 2 were used to fluorometrically measure resting [Zn2+]i (0.23 +/- 0.03 nM) and intracellular Ca2+ concentration ([Ca2+]i) (36 +/- 7 nM). Fluorescence quenching by the heavy metal chelator N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine was used to quantitate [Zn2+]i. The thiol-reactive oxidants hypochlorous acid (0.1 mM) and selenite (1 mM) increased [Zn2+]i to 7.7 +/- 1.7 and 6.1 +/- 1.7 nM, respectively, within 5 min. Dithiothreitol (0.5 mM), a disulfide-reducing agent, rapidly restored normal [Zn2+]i. The oxidants did not affect [Ca2+]i. However, depolarization-induced Ca2+ transients and Ca2+ currents were zinc dependent. [Zn2+]i-associated fluorescence was substantial and, if ignored, it led to overestimation of [Ca2+]i by approximately twofold before oxidant treatment and by approximately eightfold after oxidants. The results demonstrate that [Zn2+]i 1) can be greatly increased by thiol-reactive oxidants; 2) may contribute to oxidant-induced alterations of excitation-contraction coupling; and 3) has strong fura 2 fluorescence which, if overlooked, can lead to significant overestimation of [Ca2+]i. THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
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Science Signaling. ISSN 1937-9145 (online), 1945-0877 (print). Pre-2008: Science's STKE. ISSN 1525-8882