Cardiac energetics, cell volumes, sodium fluxes, and membrane permeability: NMR studies of cold ischemia.
Intracellular sodium accumulation, cellular swelling, and energy deficiency are ischemia-associated processes that participate in the transition to irreversible ischemic injury. This study aims to determine the relationship among these parameters in intact rat hearts during global ischemia at 4 degrees C. High-energy phosphates were determined by 31P nuclear magnetic resonance, intracellular sodium accumulation was measured by 23Na spectroscopy with the shift reagent dysprosium triethyl tetraaminohexaacetic acid [Dy(TTHA)3(-)], and cell volumes were measured by 59Co and 1H spectroscopy with use of the extracellular marker Co(CN)3-(6). Intracellular sodium flux rates were 1.53 +/- 0.17, 0.17 +/- 0.05, and 0.30 +/- 0.06 mumol.g dry wt-1.min-1 at 0-1.5, 2-7, and 9-12 h, respectively. Sodium influx resulted in accumulation of the ion: 10% after 4 h, 16% after 10 h, and 29% after 12 h. Water followed sodium into the cells at two constant molar ratios (Na+/H2O): 3.80 +/- 0.15 x 10(-3) during the first 8 h of ischemia and 7.8 x 10(-3) at 8-12 h. Relative to initial intracellular volume, cells swelled by 38% after 8 h and 46% after 12 h; reperfusion reduced cellular swelling to 25 and 36%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
Askenasy
N
N
School of Chemistry, Tel Aviv University, Israel.
Vivi
A
A
Tassini
M
M
Navon
G
G
D000818:Animals; D002463:Cell Membrane Permeability; D003080:Cold Temperature; D004734:Energy Metabolism; D005110:Extracellular Space / Q000378:metabolism; D006439:Hemodynamics; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D017202:Myocardial Ischemia / Q000378:metabolism* / Q000503:physiopathology; D009206:Myocardium / Q000378:metabolism*; D009994:Osmolar Concentration; D051381:Rats; D017207:Rats, Sprague-Dawley; D012964:Sodium / Q000378:metabolism*; D014018:Tissue Distribution
D012964:Sodium