Preconditioning by isoflurane elicits mitochondrial protective mechanisms independent of sarcolemmal KATP channel in mouse cardiomyocytes. J Cardiovasc Pharmacol 2013 May;61(5):369-77
Date
01/16/2013Pubmed ID
23318991Pubmed Central ID
PMC3648596DOI
10.1097/FJC.0b013e318285f55bScopus ID
2-s2.0-84877596078 (requires institutional sign-in at Scopus site) 5 CitationsAbstract
Cardiac mitochondria and the sarcolemmal (sarc)KATP channels contribute to cardioprotective signaling of anesthetic-induced preconditioning. Changes in mitochondrial bioenergetics influence the sarcolemmal ATP-sensitive K (sarcKATP) channel function, but whether this channel has impacts on mitochondria is uncertain. We used the mouse model with deleted pore-forming Kir6.2 subunit of sarcKATP channel (Kir6.2 KO) to investigate whether the functional sarcKATP channels are necessary for isoflurane activation of mitochondrial protective mechanisms. Ventricular cardiomyocytes were isolated from C57Bl6 wild-type (WT) and Kir6.2 KO mouse hearts. Flavoprotein autofluorescence, mitochondrial reactive oxygen species production, and mitochondrial membrane potential were monitored by laser-scanning confocal microscopy in intact cardiomyocytes. Cell survival was assessed using H2O2-induced stress. Isoflurane (0.5 mM) increased flavoprotein fluorescence to 180% ± 14% and 190% ± 15% and reactive oxygen species production to 118% ± 2% and 124% ± 6% of baseline in WT and Kir6.2 KO myocytes, respectively. Tetramethylrhodamine ethyl ester fluorescence decreased to 84% ± 6% in WT and to 86% ± 4% in Kir6.2 KO myocytes. This effect was abolished by 5HD. Pretreatment with isoflurane decreased the stress-induced cell death from 31% ± 1% to 21% ± 1% in WT and from 44% ± 2% to 35% ± 2% in Kir6.2 KO myocytes. In conclusion, Kir6.2 deletion increases the sensitivity of intact cardiomyocytes to oxidative stress, but does not alter the isoflurane-elicited protective mitochondrial mechanisms, suggesting independent roles for cardiac mitochondria and sarcKATP channels in anesthetic-induced preconditioning by isoflurane.
Author List
Muravyeva M, Sedlic F, Dolan N, Bosnjak ZJ, Stadnicka AAuthor
Maria Y. Muravyeva MD, PhD Assistant Professor in the Anesthesiology department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
Anesthetics, InhalationAnimals
Cell Survival
Flavoproteins
Fluorescence
Heart Ventricles
Ischemic Preconditioning, Myocardial
Isoflurane
Male
Membrane Potential, Mitochondrial
Mice
Mice, Inbred C57BL
Microscopy, Confocal
Mitochondria, Heart
Myocytes, Cardiac
Oxidative Stress
Potassium Channels, Inwardly Rectifying
Reactive Oxygen Species
Sarcolemma
