The longitudinal relaxation time (T1) of the intracellular 23Na NMR signal in the isolated perfused rat heart during hypoxia and reoxygenation

✍ Scribed by Lawrence S. Prince; Sandra K. Miller; Gerald M. Pohost; Gabriel A. Elgavish

• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: English
• Weight: 426 KB
• Volume: 23
• Category: Article
• ISSN: 0740-3194
• DOI: 10.1002/mrm.1910230218

✦ Synopsis

Abstract

Each of six perfused rat hearts was subjected to 30 min of hypoxia followed by 60 min of reoxygenation. Inversion‐recovery data on the intracellular Na NMR signal, differentiated by a shift reagent, 6 m__M__ Dy(PPP)~2~, were obtained every 5 min, and T~1~ values were calculated. The T~1~ of the intracellular Na signal did not show any significant change either during hypoxia or upon reoxygenation, although the level of Na~i~ increased about 50%. Such an increase of total Na~i~, is expected to reduce the observed relaxation rate by diluting the fraction of Na~i~, ions that interact with intracellular polyelectrolytes. The observed constancy of T~1~ in our study is explained on the basis of the typical values of the dissociation constants of sodium ions, in aqueous solutions, in interaction with polyelectrolytes. Although the constancy of intracellular sodium T~1~ during hypoxia may preclude the utilization of T~1~, weighting for the monitoring of pathology, its determination could be important for setting optimal acquisition times in high time‐resolution experiments. © 1992 Academic Press, Inc.