Erythrocyte Na+/K+ ATPase activity measured with 23Na NMR

R. Ouwerkerk, C. J A Van Echtfeld, G. E J Staal, G. Rijksen

Research output: Contribution to journalArticlepeer-review

Abstract

A 23Na NMR assay for measurement of erythrocyte Na+/K+ ATPase activity is presented. Using the nonpermeant shift reagent dysprosium tripolyphosphate the signals of intra- and extracellular sodium are separated, enabling measurement of sodium fluxes nondestructively, without the need to physically separate the cells from their environment. By increasing membrane permeability with nystatin we have shown that the assay allows the detection of differences in membrane permeability. With low doses of nystatin the ouabain-sensitive sodium flux increased more than twofold. With high doses of nystatin the Na+/K+ pump could not prevent an almost total equilibration of intra- and extracellular sodium. All sodium that entered the cells remained NMR visible, proving that sodium influx can be measured quantitatively. 31P NMR spectra taken before and after the assay revealed a slight acidification of the cells and no significance change in ATP concentration. No evidence of Dy3+ entering the cell was observed.

Original languageEnglish (US)
Pages (from-to)164-171
Number of pages8
JournalMagnetic Resonance in Medicine
Volume12
Issue number2
StatePublished - 1989
Externally publishedYes

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Radiological and Ultrasound Technology

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