title: Isoflurane-induced postconditioning via mitochondrial calcium-activated potassium channels.
abstract: OBJECTIVE
  Activation of the mitochondrial calcium-activated potassium (mKCa) channel reportedly confers resistance to myocardial ischemic stress. However, the role of the mKCa channel in postconditioning induced by volatile anesthetic remains unclear.
  
  
  METHODS
  Male Japanese white rabbits underwent coronary artery occlusion for 30 min followed by reperfusion for 3 h. Volatile anesthetic, isoflurane, was administered at 3 min prior to reperfusion for 5 min. Rabbits were injected with the mKCa channel blocker, iberiotoxin, or the mKCa channel opener, NS1619, at 8 min prior to reperfusion. Myocardial infarct size and the area at risk (AAR) were measured at the end of the experiment.
  
  
  RESULTS
  Isoflurane significantly reduced infarct size (23.0 ± 9.8% of the AAR, P<0.05) compared with the control (44.0 ± 9.1%). Iberiotoxin abolished the cardioprotective impact of isoflurane (43.0 ± 11.6%), while iberiotoxin alone exerted no effect on infarct size (45.0 ± 9.5%). NS1619 and isoflurane/NS1619 both significantly reduced infarct size (21.0 ± 10.3% and 19.0 ± 8.8%, respectively, P<0.05 vs control group), but isoflurane/NS1619 showed no additional benefits compared with isoflurane alone.
  
  
  CONCLUSIONS
  These results indicate that activation of the mKCa channel contribute isoflurane-induced postconditioning.
authors.affiliation: Department of Anesthesiology, Tokushima University Hospital.
authors.forename: Michiko
authors.initials: M
authors.lastname: Kinoshita
authors.forename: Yasuo M
authors.initials: YM
authors.lastname: Tsutsumi
authors.forename: Kohei
authors.initials: K
authors.lastname: Fukuta
authors.forename: Asuka
authors.initials: A
authors.lastname: Kasai
authors.forename: Katsuya
authors.initials: K
authors.lastname: Tanaka
mesh_terms: D018685:Anesthetics, Inhalation / Q000494:pharmacology; D000818:Animals; D002316:Cardiotonic Agents / Q000494:pharmacology; D057775:Ischemic Postconditioning / Q000379:methods*; D007530:Isoflurane / Q000494:pharmacology*; D008297:Male; D008929:Mitochondria, Heart / Q000187:drug effects / Q000378:metabolism; D009203:Myocardial Infarction / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control; D024681:Potassium Channels, Calcium-Activated / Q000187:drug effects* / Q000378:metabolism*; D011817:Rabbits
chemical_list: D018685:Anesthetics, Inhalation; D002316:Cardiotonic Agents; D024681:Potassium Channels, Calcium-Activated; D007530:Isoflurane