title: Alterations of Na+,K(+)-ATPase activity after hypoxia and reoxygenation in the perfused rat liver: an electron microscopic cytochemical study.
abstract: OBJECTIVE
  Using the cerium technique for ultrastructural cytochemical studies, Na+,K(+)-ATPase activity was investigated in hypoxic and reoxygenated rat liver.
  
  
  METHODS
  In the control group, the livers were perfused with oxygenated hemoglobin-free Krebs-Henseleit buffer for 1 h. For hypoxia (60 min), the flow rate of the perfusate was decreased and oxygen was replaced by nitrogen. For reoxygenation, the liver was reperfused under oxygenated conditions for 5 min after 60 min of hypoxia.
  
  
  RESULTS
  In control livers, a strong Na+,K(+)-ATPase activity was detected at the basolateral membrane of hepatocytes while the apical membrane forming the bile canaliculi did not display any staining. In hypoxic livers, Na+,K(+)-ATPase activity had ceased in the plasma membrane of hepatocytes. In reoxygenated livers, Na+,K(+)-ATPase was rapidly reactivated in the basolateral hepatic membrane. The membrane of blebs generated during the hypoxic phase also showed enzyme activity. In addition, a striking accumulation of reaction product could be observed in about 10% of the apical membranes lining the bile canaliculi.
  
  
  CONCLUSIONS
  The results indicate a plasticity of the Na+,K(+)-ATPase in hypoxic and reoxygenated rat liver.
authors.affiliation: Department of Anatomy and Cell Biology II, University of Heidelberg, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Angermüller
authors.forename: M
authors.initials: M
authors.lastname: Schunk
authors.forename: K
authors.initials: K
authors.lastname: Kusterer
authors.forename: T
authors.initials: T
authors.lastname: Konrad
authors.forename: K H
authors.initials: KH
authors.lastname: Usadel
mesh_terms: D000818:Animals; D015687:Cell Hypoxia / Q000187:drug effects; D005260:Female; D006651:Histocytochemistry; D008099:Liver / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D008854:Microscopy, Electron; D010100:Oxygen / Q000627:therapeutic use*; D010477:Perfusion; D051381:Rats; D017208:Rats, Wistar; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
chemical_list: D000254:Sodium-Potassium-Exchanging ATPase; D010100:Oxygen