title: Ouabain exerts cytoprotection by diminishing the intracellular K(+) concentration increase caused by distinct stimuli in human leukemic cells.
abstract: OBJECTIVE
  We tested if modulation of cytosolic K(+) levels by ouabain, an inhibitor of Na(+) /K(+) -ATPase, exerts cytoprotection against distinct stressful stimuli in human leukemic cells.
  
  
  METHODS
  The cytosolic K(+) , Na(+) or Ca(2+) levels and the cytotoxicity were evaluated by flow cytometry.
  
  
  RESULTS
  Various cytotoxic chemicals and ultraviolet irradiation induced cell death and increased intracellular concentrations of K(+) , Na(+) or Ca(2+) . Ouabain reduced the cytotoxicity and the elevation of cytosolic levels of K(+) but not those of Na(+) or Ca(2+) .
  
  
  CONCLUSIONS
  Our data thus suggest that elevated cytosolic K(+) levels are associated with the cytotoxicity in response to distinct stressful stimuli and that ouabain exerts cytoprotection most probably by regulating intracellular K(+) levels.
authors.affiliation: Faculty of Pharmacy, Kinki University, Higashiosaka, Osaka, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Takechi
authors.forename: Tetsuyuki
authors.initials: T
authors.lastname: Wada
authors.forename: Hideki
authors.initials: H
authors.lastname: Yagi
authors.forename: Takashi
authors.initials: T
authors.lastname: Masuko
authors.forename: Atsufumi
authors.initials: A
authors.lastname: Kawabata
mesh_terms: D002118:Calcium / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects / Q000502:physiology; D045744:Cell Line, Tumor; D019610:Cytoprotection / Q000187:drug effects* / Q000502:physiology; D005434:Flow Cytometry; D006801:Humans; D010042:Ouabain / Q000494:pharmacology*; D011188:Potassium / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors*; D014466:Ultraviolet Rays / Q000009:adverse effects
chemical_list: D010042:Ouabain; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium; D002118:Calcium
keywords: cytoprotection; flow cytometry; human leukemic cells; intracellular K+ concentration; ouabain