title: Significantly decreased extracellular magnesium in brains of gerbils subjected to cerebral ischemia.
abstract: BACKGROUND
  A method for determining extracellular magnesium (Mg) levels in gerbil brain dialysates was developed by microdialysis and graphite furnace atomic absorption spectroscopy (GFAAS).
  
  
  METHODS
  Two microdialysis probes were inserted into the right and left cortices of a gerbil subjected to a focal cerebral ischemia. Extracellular magnesium concentrations in diluted dialysates were 1.10 and 1.12 ppb in the ipsilateral and contralateral gerbil cortex, respectively.
  
  
  RESULTS
  During cerebral ischemia, these concentrations decreased significantly to approximately 60% of basal in the ipsilateral cortex, whereas no changes in the contralateral cortex were detected. Extracellular magnesium concentrations returned to baseline within 3 h of reperfusion. The linearity of magnesium concentrations ranged from 0.50 to 5.0 ppb with a detection limit of 0.03 ppb in the present assay. A complete analysis can be performed within 2 min. The intra- and interassay precision was < 5%.
  
  
  CONCLUSIONS
  To our knowledge, the present method is the first analytical assay measuring dynamic extracellular magnesium concentrations during cerebral ischemia by microdialysis and graphite furnace atomic absorption spectroscopy.
authors.affiliation: Department of Medical Laboratory, Taichung Veterans General Hospital, Taichung 407, Taiwan.
authors.forename: Ming-Shih
authors.initials: MS
authors.lastname: Lee
authors.forename: Yuh-Shen
authors.initials: YS
authors.lastname: Wu
authors.forename: Dar-Yu
authors.initials: DY
authors.lastname: Yang
authors.forename: Jen-Bin
authors.initials: JB
authors.lastname: Lee
authors.forename: Fu-Chou
authors.initials: FC
authors.lastname: Cheng
mesh_terms: D000818:Animals; D001923:Brain Chemistry / Q000502:physiology*; D002545:Brain Ischemia / Q000378:metabolism*; D002540:Cerebral Cortex / Q000737:chemistry / Q000378:metabolism; D002560:Cerebrovascular Circulation / Q000502:physiology; D005110:Extracellular Space / Q000378:metabolism*; D005849:Gerbillinae; D017078:Laser-Doppler Flowmetry; D008274:Magnesium / Q000378:metabolism*; D008297:Male; D017551:Microdialysis; D015424:Reperfusion; D013054:Spectrophotometry, Atomic
chemical_list: D008274:Magnesium