title: Ischemic preconditioning reduces right ventricular infarct size through opening of mitochondrial potassium channels.
abstract: OBJECTIVE
  We investigated whether ischemic preconditioning (IPC) protects the right ventricular (RV) myocardium against ischemic injury in hearts treated with the specific mitochondrial ATP-sensitive potassium (K(ATP)) channel blocker 5-hydroxydecanoate (5-HD).
  
  
  METHODS
  Hearts from male Wistar rats (300 g, n = 39) were isolated and perfused with Krebs-Henseleit buffer and randomized to no IPC (control, n = 16), IPC (n = 16) or IPC preceded by addition of 5-HD (100 µM, n = 7). IPC consisted of 2 × 5 min of global ischemia followed by 40 min of global ischemia and 120 min of reperfusion. The effect of IPC on RV myocardial infarct size was evaluated by measurement of the infarct size/area-at-risk ratio (RVIS/AAR). Postischemic RV function was evaluated by RV pressures.
  
  
  RESULTS
  IPC produced a marked decrease in RVIS/AAR (24.4 ± 8.1 vs. 42.6 ± 10.6%, p < 0.0001) and improved hemodynamic recovery of RV contractile function compared with the control group. We found no difference in RVIS/AAR (45.2 ± 4.4 vs. 42.6 ± 10.6, p > 0.05) or hemodynamic recovery between IPC + 5-HD and control hearts. Blockade of mitochondrial K(ATP) channels by 5-HD abolished the cardioprotective response to IPC.
  
  
  CONCLUSIONS
  IPC reduces RV myocardial infarct size and improves postischemic RV contractile function in the isolated rat heart, possibly through opening of the mitochondrial K(ATP) channel.
authors.affiliation: Institute of Clinical Medicine, Cardiology Research, Aarhus University Hospital, Aarhus, Denmark. asger.andersen@ki.au.dk
authors.forename: Asger
authors.initials: A
authors.lastname: Andersen
authors.forename: Jonas Agerlund
authors.initials: JA
authors.lastname: Povlsen
authors.forename: Hans Erik
authors.initials: HE
authors.lastname: Bøtker
authors.forename: Jens Erik
authors.initials: JE
authors.lastname: Nielsen-Kudsk
mesh_terms: D000818:Animals; D003652:Decanoic Acids / Q000494:pharmacology*; D006352:Heart Ventricles / Q000187:drug effects; D006880:Hydroxy Acids / Q000494:pharmacology*; D019157:Ischemic Preconditioning, Myocardial / Q000379:methods*; D008297:Male; D008929:Mitochondria, Heart / Q000187:drug effects*; D009203:Myocardial Infarction / Q000188:drug therapy*; D026902:Potassium Channel Blockers / Q000494:pharmacology*; D015221:Potassium Channels / Q000187:drug effects; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar
chemical_list: D003652:Decanoic Acids; D006880:Hydroxy Acids; D026902:Potassium Channel Blockers; D015221:Potassium Channels; C052853:5-hydroxydecanoic acid