Winter P M, Seshan V, Makos J D, Sherry A D, Malloy C R, Bansal N
Biomedical Engineering Program, University of Texas at Arlington, Arlington 76019, Texas, USA.
J Appl Physiol (1985). 1998 Nov;85(5):1806-12. doi: 10.1152/jappl.1998.85.5.1806.
A method is presented to measure the absolute concentration of intracellular Na+ ([Na+]i) in vivo by using interleaved 23Na- and 31P-nuclear magnetic resonance (NMR) spectroscopy and TmDOTP5- as shift reagent and chemical marker of tissue extracellular space (ECS). The technique was used to determine [Na+]i and relative ECS in livers of control rats (21 +/- 3 and 0.11 +/- 0.02 mM, respectively) and in rats exposed to carbon tetrachloride (103 +/- 29 and 0.23 +/- 0.03 mM, respectively). The NMR measurements were confirmed independently on excised tissue samples by using atomic absorption spectroscopy. The results confirm that TmDOTP5- can be used as a combined cation shift reagent and ECS marker, thereby allowing quantitation of [Na+]i in vivo by NMR.
