ATP consumption by uncoupled mitochondria activates sarcolemmal K(ATP) channels in cardiac myocytes.

We tested whether close coupling exists between mitochondria and sarcolemma by monitoring whole cell ATP-sensitive K(+) (K(ATP)) current (I(K,ATP)) as an index of subsarcolemmal energy state during mitochondrial perturbation. In rabbit ventricular myocytes, either pinacidil or the mitochondrial uncoupler dinitrophenol (DNP), which rapidly switches mitochondria from net ATP synthesis to net ATP hydrolysis, had little immediate effect on I(K,ATP). In contrast, in the presence of pinacidil, exposure to 100 microM DNP rapidly activated I(K,ATP) with complex kinetics consisting of a quick rise [time constant of I(K,ATP) increase (tau) = 0.13 +/- 0.01 min], an early partial recovery (tau = 0.43 +/- 0.04 min), and then a more gradual increase. This DNP-induced activation of I(K,ATP) was reversible and accompanied by mitochondrial flavoprotein oxidation. The F(1)F(0)-ATPase inhibitor oligomycin abolished the DNP-induced activation of I(K,ATP). The initial rapid rise in I(K,ATP) was blunted by atractyloside (an adenine nucleotide translocator inhibitor), leaving only a slow increase (tau = 0.66 +/- 0.17 min, P < 0.01). 2,4-Dinitrofluorobenzene (a creatine kinase inhibitor) slowed both the rapid rise (tau = 0.20 +/- 0.01 min, P < 0.05) and the subsequent declining phase (tau = 0.88 +/- 0.19 min, P < 0.05). From single K(ATP) channel recordings, we excluded a direct effect of DNP on K(ATP) channels. Taken together, these results indicate that rapid changes in F(1)F(0)-ATPase function dramatically alter subsarcolemmal energy charge, as reported by pinacidil-primed K(ATP) channel activity, revealing cross-talk between mitochondria and sarcolemma. The effects of mitochondrial ATP hydrolysis on sarcolemmal K(ATP) channels can be rationalized by reversal of F(1)F(0)-ATPase and the facilitation of coupling by the creatine kinase system.

[1]  E. Marbán,et al.  Modulation of mitochondrial ATP-dependent K+ channels by protein kinase C. , 1998, Circulation research.

[2]  R S Balaban,et al.  Nicotinamide adenine dinucleotide fluorescence spectroscopy and imaging of isolated cardiac myocytes. , 1989, Biophysical journal.

[3]  A. Terzic,et al.  Opening of Cardiac Sarcolemmal KATP Channels by Dinitrophenol Separate from Metabolic Inhibition , 1997, The Journal of Membrane Biology.

[4]  I. Plesner,et al.  Kinetics of oligomycin inhibition and activation of Na+/K(+)-ATPase. , 1991, Biochimica et biophysica acta.

[5]  J. Walker,et al.  Large-scale chromatographic purification of F1F0-ATPase and complex I from bovine heart mitochondria. , 1996, The Biochemical journal.

[6]  B. Kholodenko,et al.  The role of adenine nucleotide translocators in regulation of oxidative phosphorylation in heart mitochondria , 1987, FEBS letters.

[7]  A. Noma,et al.  ATP-regulated K+ channels in cardiac muscle , 1983, Nature.

[8]  J. Weiss,et al.  Cardiac ATP-sensitive K+ channels. Evidence for preferential regulation by glycolysis , 1989, The Journal of general physiology.

[9]  M. Arita,et al.  Inhibition of Na(+)-K+ pump alleviates the shortening of action potential duration caused by metabolic inhibition via blockade of KATP channels in coronary perfused ventricular muscles of guinea-pigs. , 1999, Journal of molecular and cellular cardiology.

[10]  K. Tagawa,et al.  Regulatory proteins of F1F0-ATPase: Role of ATPase inhibitor , 1990, Journal of bioenergetics and biomembranes.

[11]  M. Duchen,et al.  Contributions of mitochondria to animal physiology: from homeostatic sensor to calcium signalling and cell death , 1999, The Journal of physiology.

[12]  H. Kammermeier,et al.  Why do cells need phosphocreatine and a phosphocreatine shuttle. , 1987, Journal of molecular and cellular cardiology.

[13]  A. Terzic,et al.  Pharmacological plasticity of cardiac ATP-sensitive potassium channels toward diazoxide revealed by ADP. , 1999, Proceedings of the National Academy of Sciences of the United States of America.

[14]  J C Reed,et al.  Mitochondria and apoptosis. , 1998, Science.

[15]  J N Weiss,et al.  Mechanisms of excitation‐contraction coupling failure during metabolic inhibition in guinea‐pig ventricular myocytes. , 1991, The Journal of physiology.

[16]  J. Weiss,et al.  Glycolysis preferentially inhibits ATP-sensitive K+ channels in isolated guinea pig cardiac myocytes. , 1987, Science.

[17]  J. Weiss,et al.  Evidence for Preferential Regulation by Glycolysis , 1989 .

[18]  M. Duchen,et al.  The relationship between mitochondrial state, ATP hydrolysis, [Mg2+]i and [Ca2+]i studied in isolated rat cardiomyocytes. , 1996, The Journal of physiology.

[19]  E. Marbán,et al.  Subcellular metabolic transients and mitochondrial redox waves in heart cells. , 1998, Proceedings of the National Academy of Sciences of the United States of America.

[20]  M. Wyss,et al.  Mitochondrial creatine kinase: a key enzyme of aerobic energy metabolism. , 1992, Biochimica et biophysica acta.

[21]  Yongge Liu,et al.  Mitochondrial ATP-dependent potassium channels: novel effectors of cardioprotection? , 1998, Circulation.

[22]  I. Hassinen,et al.  Mechanisms of ischemic preconditioning in rat myocardium. Roles of adenosine, cellular energy state, and mitochondrial F1F0-ATPase. , 1995, Circulation.

[23]  V. Saks,et al.  Quantitative analysis of the 'phosphocreatine shuttle': I. A probability approach to the description of phosphocreatine production in the coupled creatine kinase-ATP/ADP translocase-oxidative phosphorylation reactions in heart mitochondria. , 1993, Biochimica et biophysica acta.

[24]  E. Marbán,et al.  Oscillations of membrane current and excitability driven by metabolic oscillations in heart cells. , 1994, Science.

[25]  Y. Tsujimoto,et al.  Intracellular ATP levels determine cell death fate by apoptosis or necrosis. , 1997, Cancer research.

[26]  R. Jennings,et al.  Effect of reversible ischemia on the activity of the mitochondrial ATPase: relationship to ischemic preconditioning. , 1996, Journal of molecular and cellular cardiology.

[27]  M. Dubick,et al.  Inhibition of cardiac creatine phosphokinase by fluorodinitrobenzene. , 1977, Life sciences.

[28]  I. Hassinen,et al.  Role of cellular energetics in ischemia-reperfusion and ischemic preconditioning of myocardium , 1998, Molecular and Cellular Biochemistry.