title: Reactive oxygen species-induced stimulation of 5'AMP-activated protein kinase mediates sevoflurane-induced cardioprotection.
abstract: BACKGROUND
  5'AMP-activated protein kinase (AMPK), a well-known regulator of cellular energy status, is also implicated in ischemic preconditioning leading to cardioprotection. We hypothesized that AMPK is involved in anesthetic-induced cardioprotection and that this activation is mediated by reactive oxygen species (ROS).
  
  
  RESULTS
  Isolated Langendorff-perfused rat hearts were subjected to 35 minutes of global ischemia (I) followed by 120 minutes of reperfusion (I/R). Hearts were assigned to a control group (Con) or a sevoflurane (Sevo) group receiving 3 times 5-minute episodes of sevoflurane (2.5vol%) before I/R. Phosphorylation of both AMPK and endothelial nitric oxide synthase (eNOS) were determined by Western blot analysis. Cardioprotection was assessed after I/R from recovery of left ventricular pressure and from infarct size (triphenyltetrazolium chloride staining). In the control group, ischemia resulted in a 2-fold increase in phosphorylation levels of AMPK (Con 0.13+/-0.01 versus Con-I 0.28+/-0.05, P<0.05), which was sustained after 120 minutes of reperfusion (Con-I/R 0.26+/-0.02, P<0.05). Sevoflurane preconditioning had no affect on AMPK phosphorylation before ischemia (Sevo 0.12+/-0.03, P>0.05), but almost doubled the increase in AMPK phosphorylation relative to control after ischemia (Sevo-I 0.48+/-0.09, P<0.05), an effect that was sustained after reperfusion (Sevo-I/R 0.49+/-0.12, P<0.05). The AMPK-inhibitor compound C (10 micromol/L) reduced the sevoflurane-mediated increase in phosphorylation of AMPK and its target eNOS and abolished cardioprotection. The ROS-scavenger n-(2-mercaptopropionyl)-glycine (1 mmol/L) blunted the sevoflurane-mediated increase in AMPK and eNOS phosphorylation and prevented cardioprotection.
  
  
  CONCLUSIONS
  Sevoflurane-induced AMPK activation protects the heart against ischemia and reperfusion injury and relies on upstream production of ROS.
authors.affiliation: Department of Anesthesiology, VU University Medical Center, Amsterdam, The Netherlands. TTTr.lamberts@vumc.nl
authors.forename: Regis R
authors.initials: RR
authors.lastname: Lamberts
authors.forename: Geert
authors.initials: G
authors.lastname: Onderwater
authors.forename: Nazha
authors.initials: N
authors.lastname: Hamdani
authors.forename: M Jumoke A
authors.initials: MJ
authors.lastname: Vreden
authors.forename: Jeroen
authors.initials: J
authors.lastname: Steenhuisen
authors.forename: Etto C
authors.initials: EC
authors.lastname: Eringa
authors.forename: Stephan A
authors.initials: SA
authors.lastname: Loer
authors.forename: Ger J M
authors.initials: GJ
authors.lastname: Stienen
authors.forename: R Arthur
authors.initials: RA
authors.lastname: Bouwman
mesh_terms: D055372:AMP-Activated Protein Kinases / Q000502:physiology*; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000818:Animals; D004789:Enzyme Activation / Q000187:drug effects; D008297:Male; D008738:Methyl Ethers / Q000494:pharmacology*; D015428:Myocardial Reperfusion Injury / Q000517:prevention & control*; D010766:Phosphorylation; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism*; D000077149:Sevoflurane
chemical_list: D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D017382:Reactive Oxygen Species; D000077149:Sevoflurane; D055372:AMP-Activated Protein Kinases