Faculty Collaboration Database

Monitoring mitochondrial electron fluxes using NAD(P)H-flavoprotein fluorometry reveals complex action of isoflurane on cardiomyocytes. Biochim Biophys Acta 2010 Oct;1797(10):1749-58

Date

07/22/2010

Pubmed ID

20646994

Pubmed Central ID

PMC2926458

DOI

10.1016/j.bbabio.2010.07.009

Scopus ID

2-s2.0-77955551744 (requires institutional sign-in at Scopus site)   23 Citations

Abstract

Mitochondrial bioenergetic studies mostly rely on isolated mitochondria thus excluding the regulatory role of other cellular compartments important for the overall mitochondrial function. In intact cardiomyocytes, we followed the dynamics of electron fluxes along specific sites of the electron transport chain (ETC) by simultaneous detection of NAD(P)H and flavoprotein (FP) fluorescence intensities using a laser-scanning confocal microscope. This method was used to delineate the effects of isoflurane, a volatile anesthetic and cardioprotective agent, on the ETC. Comparison to the effects of well-characterized ETC inhibitors and uncoupling agent revealed two distinct effects of isoflurane: uncoupling-induced mitochondrial depolarization and inhibition of ETC at the level of complex I. In correlation, oxygen consumption measurements in cardiomyocytes confirmed a dose-dependent, dual effect of isoflurane, and in isolated mitochondria an obstruction of the ETC primarily at the level of complex I. These effects are likely responsible for the reported mild stimulation of mitochondrial reactive oxygen species (ROS) production required for the cardioprotective effects of isoflurane. In conclusion, isoflurane exhibits complex effects on the ETC in intact cardiomyocytes, altering its electron fluxes, and thereby enhancing ROS production. The NAD(P)H-FP fluorometry is a useful method for exploring the effect of drugs on mitochondria and identifying their specific sites of action within the ETC of intact cardiomyocytes.

Author List

Sedlic F, Pravdic D, Hirata N, Mio Y, Sepac A, Camara AK, Wakatsuki T, Bosnjak ZJ, Bienengraeber M

Author

Amadou K. Camara PhD Professor in the Anesthesiology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Anesthetics, Inhalation
Animals
Cells, Cultured
Dose-Response Relationship, Drug
Electron Transport
Electron Transport Complex I
Flavoproteins
Fluorometry
Isoflurane
Male
Membrane Potential, Mitochondrial
Microscopy, Confocal
Mitochondria, Heart
Models, Biological
Myocytes, Cardiac
NADP
Oxidation-Reduction
Oxygen Consumption
Rats
Rats, Wistar
Reactive Oxygen Species