title: Delayed cardioprotection by isoflurane: role of K(ATP) channels.
abstract: Isoflurane mimics the cardioprotective effect of acute ischemic preconditioning with an acute memory phase. We determined whether isoflurane can induce delayed cardioprotection, the involvement of ATP-sensitive potassium (K(ATP)) channels, and cellular location of the channels. Neonatal New Zealand White rabbits at 7-10 days of age (n = 5-16/group) were exposed to 1% isoflurane-100% oxygen for 2 h. Hearts exposed 2 h to 100% oxygen served as untreated controls. Twenty-four hours later resistance to myocardial ischemia was determined using an isolated perfused heart model. Isoflurane significantly reduced infarct size/area at risk (means +/- SD) by 50% (10 +/- 5%) versus untreated controls (20 +/- 6%). Isoflurane increased recovery of preischemic left ventricular developed pressure by 28% (69 +/- 4%) versus untreated controls (54 +/- 6%). The mitochondrial K(ATP) channel blocker 5-hydroxydecanoate (5-HD) completely (55 +/- 3%) and the sarcolemmal K(ATP) channel blocker HMR 1098 partially (62 +/- 3%) attenuated the cardioprotective effects of isoflurane. The combination of 5-HD and HMR-1098 completely abolished the cardioprotective effect of isoflurane (56 +/- 5%). We conclude that both mitochondrial and sarcolemmal K(ATP) channels contribute to isoflurane-induced delayed cardioprotection.
authors.affiliation: Division of Pediatric Surgery, Medical College of Wisconsin, Milwaukee, 53226, USA.
authors.forename: Marija
authors.initials: M
authors.lastname: Tonkovic-Capin
authors.forename: Garrett J
authors.initials: GJ
authors.lastname: Gross
authors.forename: Zeljko J
authors.initials: ZJ
authors.lastname: Bosnjak
authors.forename: James S
authors.initials: JS
authors.lastname: Tweddell
authors.forename: Colleen M
authors.initials: CM
authors.lastname: Fitzpatrick
authors.forename: John E
authors.initials: JE
authors.lastname: Baker
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D001549:Benzamides; D019610:Cytoprotection / Q000187:drug effects; D003652:Decanoic Acids / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006321:Heart / Q000187:drug effects* / Q000503:physiopathology; D006880:Hydroxy Acids / Q000494:pharmacology; D066298:In Vitro Techniques; D007530:Isoflurane / Q000494:pharmacology*; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D009203:Myocardial Infarction / Q000473:pathology / Q000503:physiopathology / Q000517:prevention & control; D017202:Myocardial Ischemia / Q000503:physiopathology*; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology; D026902:Potassium Channel Blockers / Q000494:pharmacology; D015221:Potassium Channels / Q000378:metabolism*; D011817:Rabbits; D012508:Sarcolemma / Q000378:metabolism; D013997:Time Factors; D016277:Ventricular Function, Left / Q000187:drug effects
chemical_list: D001549:Benzamides; D003652:Decanoic Acids; D006880:Hydroxy Acids; D026902:Potassium Channel Blockers; D015221:Potassium Channels; C052853:5-hydroxydecanoic acid; D000255:Adenosine Triphosphate; C410297:HMR 1098; D007530:Isoflurane