NMR measurements of Na+ and cellular energy in ischemic rat heart

Role of Na+-H+ exchange

Martin Pike, C. S. Luo, M. D. Clark, K. A. Kirk, M. Kitakaze, M. C. Madden, E. J. Cragoe, G. M. Pohost

Research output: Contribution to journalArticle

209 Citations (Scopus)

Abstract

Interleaved 23Na- and 31P-nuclear magnetic resonance (NMR) spectra were continuously collected on perfused rat hearts subjected to low-flow ischemia (30 min, 10% flow) or zero-flow ischemia (21 min) followed by reperfusion. During untreated low-flow and zero-flow ischemia, intracellular Na+ (Na(i)/+) increased by 53 ± 11 (±SE) and 78 ± 8%, respectively, and remained elevated for zero-flow hearts. However, during both low- and zero- flow ischemia, Na(i)/+ did not increase in hearts treated with the Na+-H+ exchange inhibitor, 5-(N-ethyl-N-isopropyl)amiloride (EIPA). The pH decreases during ischemia were unchanged. EIPA treatment reduced ATP depletion during ischemia. During reperfusion from zero-flow ischemia, EIPA-treated hearts displayed more rapid and extensive recoveries of phosphocreatine and ATP. Recovery of left ventricular developed pressure was improved for zero-flow hearts treated with EIPA during the ischemic period exclusively (104 ± 13%) compared with untreated hearts (36 ± 21%). These data indicate that Na+- H+ exchange is an important mechanism for Na(i)/+ accumulation, but not for pH regulation, during myocardial ischemia. Additionally, Na(i)/+ homeostasis plays an important role in the postischemic recovery of cellular energy and ventricular function.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume265
Issue number6 34-6
StatePublished - 1993
Externally publishedYes

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Magnetic Resonance Spectroscopy
Ischemia
Amiloride
Reperfusion
Adenosine Triphosphate
Phosphocreatine
Ventricular Function
Ventricular Pressure
Myocardial Ischemia
Homeostasis

Keywords

  • cardiac function
  • ischemia

ASJC Scopus subject areas

  • Physiology

Cite this

Pike, M., Luo, C. S., Clark, M. D., Kirk, K. A., Kitakaze, M., Madden, M. C., ... Pohost, G. M. (1993). NMR measurements of Na+ and cellular energy in ischemic rat heart: Role of Na+-H+ exchange. American Journal of Physiology - Heart and Circulatory Physiology, 265(6 34-6).

NMR measurements of Na+ and cellular energy in ischemic rat heart : Role of Na+-H+ exchange. / Pike, Martin; Luo, C. S.; Clark, M. D.; Kirk, K. A.; Kitakaze, M.; Madden, M. C.; Cragoe, E. J.; Pohost, G. M.

In: American Journal of Physiology - Heart and Circulatory Physiology, Vol. 265, No. 6 34-6, 1993.

Research output: Contribution to journalArticle

Pike, M, Luo, CS, Clark, MD, Kirk, KA, Kitakaze, M, Madden, MC, Cragoe, EJ & Pohost, GM 1993, 'NMR measurements of Na+ and cellular energy in ischemic rat heart: Role of Na+-H+ exchange', American Journal of Physiology - Heart and Circulatory Physiology, vol. 265, no. 6 34-6.
Pike, Martin ; Luo, C. S. ; Clark, M. D. ; Kirk, K. A. ; Kitakaze, M. ; Madden, M. C. ; Cragoe, E. J. ; Pohost, G. M. / NMR measurements of Na+ and cellular energy in ischemic rat heart : Role of Na+-H+ exchange. In: American Journal of Physiology - Heart and Circulatory Physiology. 1993 ; Vol. 265, No. 6 34-6.
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