Original ArticlePreconditioning by Isoflurane Elicits Mitochondrial Protective Mechanisms Independent of Sarcolemmal KATP Channel in Mouse CardiomyocytesMuravyeva, Maria MD, PhD; Sedlic, Filip MD, PhD; Dolan, Nicholas; Bosnjak, Zeljko J. PhD; Stadnicka, Anna PhDAuthor Information Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI. Reprints: Anna Stadnicka, PhD, Department of Anesthesiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226 (e-mail: email@example.com). This study was supported in part by the National Institutes of Health grants P01GM066730 and R01HL034708 (to Z.J.B.), Bethesda, MD. The authors declare no conflicts of interest. Received August 17, 2012 Accepted January 03, 2013 Journal of Cardiovascular Pharmacology: May 2013 - Volume 61 - Issue 5 - p 369-377 doi: 10.1097/FJC.0b013e318285f55b Buy Metrics Abstract Abstract: 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. © 2013 Lippincott Williams & Wilkins, Inc.