Sodium flux and bioenergetics in the ischemic rat liver

✍ Scribed by Haywood Blum; Mary D. Osbakken; Robert G. Johnson Jr.

• Book ID: 102952331
• Publisher: John Wiley and Sons
• Year: 1991
• Tongue: English
• Weight: 613 KB
• Volume: 18
• Category: Article
• ISSN: 0740-3194
• DOI: 10.1002/mrm.1910180209

✦ Synopsis

Abstract

Concurrent ^23^Na and ^31^P nuclear magnetic resonance spectroscopy has been employed to study the effects of ischemia upon the high‐energy phosphagens and sodium ion concentration within the in vivo rat liver. High‐energy phosphates in the form of ATP were depleted within 10 min of the onset of ischemia when measured by NMR. However, similar liver samples subjected to analytical biochemistry retained 27 ± 12% of their ATP after a similar 10‐min ischemic insult. Time‐dependent ^23^Na NMR measurements, obtained in the presence of the shift reagent Dy(TTHA) to distinguish intracellular from extracellular sodium, revealed a rapid rise in the intracellular sodium when the liver was made ischemic. Intracellular and extracellular sodium concentrations approached equilibrium with an exponential time constant of 14.7 ± 7 min. The initial rate of sodium influx was calculated to be 1.50 meq · 1^−1^ · min^−1^. The results indicate that the ischemic liver has a high passive sodium permeability and that NMR detectable ^31^P signals reflect the actual availability of cytosolic high‐energy phosphates to enzymes, in this instance the membrane‐bound [Na^+^, K ^+^]‐ATPase. © 1991 Academic Press. Inc.