A sampling artifact in the microdialysis study of changes in extracellular [Mg2+] upon spinal cord injury

Jinping Yang, Gregory Robak, Danxia Liu, David J. McAdoo

Research output: Contribution to journalArticle

4 Scopus citations


Whether depletion of a substance from the extracellular fluid by removal through the dialysis probe can affect the measured efflux of that substance into the extracellular fluid upon injury is examined. When Mg2+-free artificial cerebrospinal fluid was used to perfuse the microdialysis fiber, a significant increase in collected Mg2+ was observed immediately following injury. However, when [Mg2+] inside the fiber was equal to the basal concentration in the extracellular fluid, no increase in [Mg2+] was detected. The difference between the two sets of results is attributed to efflux down an increased intracellular/extracellular [Mg2+] gradient that occurs when the basal extracellular concentration is not balanced within the fiber, but not otherwise. This is a previously unreported problem with microdialysis.

Original languageEnglish (US)
Pages (from-to)203-206
Number of pages4
JournalAnalytical Biochemistry
Issue number2
StatePublished - Feb 15 1997


ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

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