[Effect of sodium and magnesium ions on development of a "calcium paradox" in cardiac muscle].
The isolated rat heart was used to examine the impact of ion concentrations of sodium ions in the Ca-free medium on the development of cardiomyocytic damage after the former sodium ion concentration had been restored in the solution (the calcium paradox). Lowering a concentration of sodium ions in the Ca-free medium was found to enhance the development of the calcium paradox if the perfusion media contained no magnesium ions. Adding magnesium (0.125-1.2 mM) throughout the experiment reversed the action of the decreased sodium medium and contributed to the preservation of high concentrations of energy-rich compounds, to that of mitochondrial conjugation of oxidation and phosphorylation, to more than 4-fold cardiac release of myoglobin. An artificially elevated sodium ion concentration (as high as 170-220 mM) was effective in preventing cardiac energy impairments irrespective of the magnesium ion concentration. The positive action of the unchanged concentration of sodium ions during the calcium paradox was completely reversed by strophanthin. The findings are in a good agreement with the so-called sodium hypothesis of calcium paradox development.
Alabovskiĭ
V V
VV
Vinokurov
A A
AA
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D008274:Magnesium / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism*; D010085:Oxidative Phosphorylation; D051381:Rats; D012964:Sodium / Q000378:metabolism*
D012964:Sodium; D008274:Magnesium; D002118:Calcium