Multiple quantum filtered 23Na NMR spectroscopy of the isolated, perfused rat liver.
Isolated, perfused rat livers were examined by single-quantum (SQ) and double-quantum-filtered (DQ-filtered) 23Na spectroscopy during prolonged global ischemia and during perfusion with ouabain, low-buffer potassium, or lithium-enriched buffer. Baseline separation of the intracellular (Na(i)+) and extracellular (Na(e)+) sodium resonances using TmDOTP5- allowed a direct comparison of temporal changes in SQ versus DQ-filtered Na(i)+. The SQ Na(i)+ signal increased approximately 150% during the first 15 min of global ischemia and then remained relatively constant over the next 45 min, while the DQ-filtered signal steadily increased approximately 400% over the same 60 min period. In similar experiments in which all perfusate sodium was replaced by lithium, the DQ-filtered Na(i)+ signal increased approximately 180% over a similar period of ischemia. Exposure of livers to ouabain also resulted in larger increases in DQ-filtered versus SQ signal of Na(i)+. The approximately 290% increase in DQ-filtered sodium observed during perfusion of livers with a hypokalemic buffer (1.2 mM K+) could be completely reversed by continued perfusion with a buffer containing normal levels of K+ (4.7 mM). These data suggest that the DQ-filtered Na(i)+ signal of liver does not simply report an increase in [Na(i)+], but may be exquisitely sensitive to other intracellular events initiated by altered physiology.
Colet
J M
JM
Department of Chemistry, University of Texas at Dallas, Richardson, USA.
Bansal
N
N
Malloy
C R
CR
Sherry
A D
AD
D000818:Animals; D007511:Ischemia / Q000378:metabolism; D008094:Lithium / Q000494:pharmacology; D008099:Liver / Q000098:blood supply / Q000187:drug effects / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D010042:Ouabain / Q000494:pharmacology; D010477:Perfusion; D011188:Potassium / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012964:Sodium / Q000378:metabolism; D012975:Sodium Isotopes
D012975:Sodium Isotopes; D010042:Ouabain; D008094:Lithium; D012964:Sodium; D011188:Potassium