An increase in intracellular [Na+] during Ca2+ depletion is not related to Ca2+ paradox damage in rat hearts
Jansen, M.A.; Van Echteld, C.J.; Ruigrok, T.J.
American Journal of Physiology 274(3): H846-H852
1998
ISSN/ISBN: 0002-9513 PMID: 9530195 Document Number: 495983
Ca2+ paradox damage has been suggested to be determined by Na+ entry during Ca2+ depletion and exchange of Na+ for Ca2+ during Ca2+ repletion. With the use of 23Na nuclear magnetic resonance, we previously observed a Ca2+ paradox without a prior Na+ increase. We have now demonstrated a Na+ increase during Ca2+ and Mg2+ depletion without the occurrence of the Ca2+ paradox during Ca2+ repletion. Isolated rat hearts were perfused for 20 min with a Ca2+-free or a Ca2+- and Mg2+-free (Ca2+/Mg2+-free) solution under hypothermic conditions (20 and 25°C). Intracellular Na+ concentration (i, which does not contribute to the extent of the Ca2+ paradox on normothermic Ca2+ repletion. Reprinted by permission of the publisher.