Double-quantum-filtered 23Na NMR study of intracellular sodium in the perfused liver.
We acquired double-quantum-filtered 23Na NMR spectra from perfused liver, using a range of tau values from 0.2 to 24 ms, where tau is the separation between the first and second pi/2 pulses in the radio-frequency pulse sequence. For each tau value we compared the amplitude of the double-quantum-filtered 23Na NMR signal acquired from intracellular sodium ions when the liver was perfused with buffer containing the "shift reagent" Dy(PPP)2 to the amplitude of the total double-quantum-filtered 23Na NMR signal acquired when the liver was perfused with buffer containing no Dy(PPP)2. For tau < or = 4 ms, the average ratio of the two amplitudes was 0.98 +/- 0.03 (mean +/- SEM). For tau > or = 8 ms, the average ratio was significantly less than 1. These results demonstrate that double-quantum-filtered 23Na NMR signals acquired from perfused liver using short tau values arise almost exclusively from intracellular sodium ions, but double-quantum-filtered 23Na NMR signals acquired from perfused liver using long tau values contain contributions from both intracellular and extracellular sodium ions. This conclusion suggests that multiple-quantum-filtered 23Na NMR spectroscopy will be useful in studying intracellular sodium levels in the perfused liver, and possibly in the intact liver in vivo.
Lyon
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National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland 20892.
McLaughlin
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D000818:Animals; D004419:Dysprosium / Q000494:pharmacology; D007202:Indicators and Reagents; D007700:Kinetics; D007770:L-Lactate Dehydrogenase / Q000032:analysis; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D010477:Perfusion; D011122:Polyphosphates / Q000494:pharmacology; D011789:Quantum Theory; D051381:Rats; D011916:Rats, Inbred F344; D012964:Sodium / Q000378:metabolism*; D013997:Time Factors
D007202:Indicators and Reagents; D011122:Polyphosphates; D004419:Dysprosium; C048543:bis(tripolyphosphate)dysprosium(III); D012964:Sodium; D007770:L-Lactate Dehydrogenase