Acetate transiently inhibits myocardial contraction by increasing mitochondrial calcium uptake
© Schooley et al.; licensee BioMed Central. 2014
Received: 27 March 2014
Accepted: 24 November 2014
Published: 9 December 2014
There is a close relationship between cardiovascular disease and cardiac energy metabolism, and we have previously demonstrated that palmitate inhibits myocyte contraction by increasing Kv channel activity and decreasing the action potential duration. Glucose and long chain fatty acids are the major fuel sources supporting cardiac function; however, cardiac myocytes can utilize a variety of substrates for energy generation, and previous studies demonstrate the acetate is rapidly taken up and oxidized by the heart. In this study, we tested the effects of acetate on contractile function of isolated mouse ventricular myocytes.
Acute exposure of myocytes to 10 mM sodium acetate caused a marked, but transient, decrease in systolic sarcomere shortening (1.49 ± 0.20% vs. 5.58 ± 0.49% in control), accompanied by a significant increase in diastolic sarcomere length (1.81 ± 0.01 μm vs. 1.77 ± 0.01 μm in control), with a near linear dose response in the 1–10 mM range. Unlike palmitate, acetate caused no change in action potential duration; however, acetate markedly increased mitochondrial Ca2+ uptake. Moreover, pretreatment of cells with the mitochondrial Ca2+ uptake blocker, Ru-360 (10 μM), markedly suppressed the effect of acetate on contraction.
Lehninger and others have previously demonstrated that the anions of weak aliphatic acids such as acetate stimulate Ca2+ uptake in isolated mitochondria. Here we show that this effect of acetate appears to extend to isolated cardiac myocytes where it transiently modulates cell contraction.
It is well established that the cardiac myocardium is capable of oxidizing a variety of carbon sources to supply the energy required for continuous contraction. Lipids, carbohydrates, ketone bodies, and amino acids can all support some degree of ATP synthesis in the heart. The loss of metabolic flexibility in the diseased heart may lead to abnormal contractile function. For example, we recently demonstrated that mice overexpressing fatty acid transport protein (FATP4) in the heart have impaired diastolic function . Similarly, acute exposure to long chain fatty acids has been shown to cause a decrease in cardiomyocyte contractility through effects on increases in voltage gated K+ currents thus causing shortening of the action potential .
In a continued effort to understand the relationship of cardiac metabolism and cell function, we set out to test the effects of acetate on contraction. Several studies have examined the effect of acetate on cardiac contraction with equivocal results. In isolated cells, acetate tends to increase cell shortening after 10 minutes of exposure . In isolated papillary muscle and in vivo, sodium acetate has been shown to reduce contractility ,, whereas other studies suggest that acetate causes an increase in contractility . The effects of acetate on cardiovascular function in vivo are complicated by the concomitant vasodilatory effects that also must be considered . These mixed results are consistent with the idea that acetate can affect cardiac contractility, but the cellular mechanisms remain poorly understood.
Although it is typically found in low concentrations (~0.2 mM) in non-ruminant mammals , acetate oxidation can account for ~10% of the total CO2 output in humans . Acetate can be converted to acetyl CoA by acetyl CoA sythetase (AceCS2) in the mitochondrial matrix  and the resultant acetyl CoA can then enter the tricarboxylic acid (TCA) cycle. The heart is unique in that the expression of the mitochondrial AceCS2 is higher than in any other tissue, so the heart is ideally suited to use acetate as a fuel source . Metabolic studies by Randle demonstrate that acetate is rapidly oxidized in the myocardium . In some isolated heart studies, acetate combustion can account for ~90% of total respiration to the exclusion of glucose oxidation , although others suggest that at physiological workloads both acetate and glucose are effectively utilized . Acetate can also affect isolated mitochondria independent of its oxidation, where Lehninger and others have demonstrated that exposure to acetate causes a rapid increase in mitochondrial matrix Ca2+ and osmotic swelling -.
In this context, we investigated the effects of acetate on cardiac contractility in isolated cardiac myocytes. We tested the effects of acetate throughout a 10 minute exposure. The results demonstrate that acetate inhibits systolic function and increases cell relaxation within 2 minutes of exposure. The decrease in systolic function is transient, however, and contraction amplitude is restored within 10 minutes. These effects are independent of changes in action potential duration; however, the effects of acetate were inhibited by blockade of mitochondrial Ca2+ uptake with Ru-360, indicating that acetate causes effects on cardiac contraction by increasing Ca2+ uptake into the mitochondria.
All animals used in this study were male, aged 2–4 months, C57Bl6/J. All procedures complied with the standards for the care and use of animal subjects as stated in the Guide for the Care and Use of Laboratory Animals (NIH publication No. 85–23, revised 1996). Protocols were approved by the USUHS Institutional Animal Care and Use Committee.
Solutions (concentrations in mM)
Normal Tyrode Soution (NT): NaCl, 137; KCl, 5.4; NaH2PO4, 0.16; glucose, 10; MgCl2, 0.5; CaCl2, 1.8; HEPES, 5.0; NaHCO3, 3.0; pH 7.35 - 7.4.
Wittenberg Isolation Medium (WIM): NaCl, 116; KCl, 5.3; NaH2PO4, 1.2; glucose, 11.6; MgCl2, 3.7; HEPES, 20; L-glutamine, 2.0; NaHCO3, 4.4; KH2PO4, 1.5; 1X essential vitamins; 1X amino acids; pH 7.3-7.4.
Isolation of ventricular myocytes was performed as described previously ,,. Briefly, mice were anesthetized by intra-peritoneal injection with 2,2,2 tribromoethanol (250 mg/kg). Following cervical dislocation, the heart was rapidly excised and the aorta cannulated. The heart was retrogradely perfused with Ca2+-free WIM solution for 5 minutes followed by perfusion with a digestion solution containing 100 μM CaCl2 and 1 mg/mL collagenase (Type 2, Worthington Biochemical). Left ventricular cells were gently dispersed by manual trituration using a pasteur pipette in WIM solution supplemented with bovine serum albumin (1 mg/mL) and 500 μM CaCl2. Cells were washed twice with WIM solution and twice with HEPES-buffered M199 solution and stored at room temperature. Cells were used for experiments within 12 hours of isolation in all cases.
Myocyte contraction measurements
Unloaded sarcomere shortening was measured in freshly isolated ventricular myocytes, as described previously ,. Briefly, isolated myocytes were transferred into a recording chamber mounted on an Olympus X51 inverted microscope and superfused with normal Tyrode solution saturated with room air. Additions to the Tyrode solution are described in the text. The mitochondrial calcium uptake inhibitor, Ru-360, was obtained from EMD Biosciences; all other chemicals were purchased from Sigma. Typically, cells were field stimulated to contract at 1 Hz. When thapsigargin was applied to cells, the stimulation frequency was reduced to 0.5 Hz. Video images were acquired using a Myocam camera and IonWizard software (IonOptix, Inc.). All experiments were performed at room temperature.
Mitochondrial Ca2+ measurements
Freshly isolated ventricular myocytes were plated on laminin-coated (100 μg/mL) Mat-Tek dishes for fluorescence imaging. Cells were loaded with Rhod-2-AM (5 μM) for 30 minutes in normal Tyrode solution containing probenecid (500 μM) to inhibit dye export and 200 μM MnCl2 to quench cytoplasmic fluorescence as has been previously reported ,. After loading, cells were washed twice with normal Tyrode solution supplemented with probenecid and 200 μM MnCl2 and transferred to the microscope stage. Cell images were obtained every 10 seconds for 10 minutes. Data were plotted as background-subtracted Rhod-2-AM fluorescence normalized to mean signal during the first 6 images recorded prior to addition of acetate.
Action potential measurements
Action potentials were measured in freshly isolated ventricular myocytes using whole cell current clamp. Briefly, following acquisition of the whole cell mode, cell holding potential was adjusted to −70 mV using current injection. Action potentials were evoked by suprathreshold stimuli (2 nA, 3 msec) delivered at 1 Hz. Action potentials were recorded continuously during 5 minute exposure to acetate followed by 5 minutes washout. Average traces constructed from 25 consecutive action potentials during control, acetate exposure (2 minutes) and washout (5 minutes) were analyzed. Action potential duration (APD90) was determined at 90% repolarization and referenced to the peak of the action potential.
All data were analyzed using ClampFit, IonWizard, ImageJ and Microsoft Excel software and (except where noted) results are presented as mean ± SEM (standard error of the mean). Statistical analysis was performed with built-in functions of Excel or with the Sigma XL software add-in. Statistical tests and p-values are denoted in the figure legend and text where appropriate.
Acute exposure to acetate transiently impairs cardiac contraction and increases diastolic sarcomere length
Acetate exposure does not affect the action potential duration
Acetate exposure stimulates mitochondrial Ca2+ uptake
Inhibition of mitochondrial Ca2+ uptake attenuates the effects of acetate on fractional shortening and diastolic sarcomere length
Partial inhibition of SERCA inhibits recovery of systolic function during acetate application
Acetate and cardiac function
There have been previous studies that have examined the effects of acetate on cardiovascular function and energetics in different contexts. Consistent with the results of the present study, acetate is reported to exhibit negative inotropic effects which appear to be transient ,. It should also be noted that acetate infusion can also cause an acute reduction of the blood pressure that is most likely dependent on the increase in AMP associated with the conversion of acetate to acetyl CoA and local release of the vasodilator adenosine , complicating the interpretation of experiments in vivo. Nevertheless, the data in the present study indicate that acetate exerts effects on cardiac contraction by directly modulating myocyte function, at least partially independent of energy metabolism.
A possible role for mitochondrial Ca2+ uptake in regulating contractile function
The present data provide evidence for a calcium-dependent mechanism linking acetate exposure with contractile function. Unlike the long chain fatty acid palmitate , the short chain fatty acid acetate caused no marked change in APD. Instead, we provide evidence that acetate caused a marked increased in mitochondrial Ca2+ accumulation. Moreover, the effect of acetate was markedly attenuated by pretreatment of myocytes with Ru-360, an inhibitor of mitochondrial Ca2+ uptake. Ru-360 is commonly used to inhibit mitochondrial Ca2+ uptake in a number of studies due to its ability to permeate cell membranes and it has been previously shown to have little if any effect on other transmembrane Ca2+ transport processes, including SR Ca2+ uptake and release, L-type Ca2+ channel and sodium calcium exchange function . Our data is consistent with the conclusion that acetate uptake is coupled with an increase in mitochondrial Ca2+ and that this decreases, at least transiently, the amount of Ca2+ available for contraction of unloaded cardiomyocytes.
Interestingly, the effects of acetate on cell contraction were transient, with complete recovery of fractional shortening within 10 minutes of continuous exposure. This result could imply that as Ca2+ is sequestered in the mitochondria in the presence of acetate, additional Ca2+ enters the cell and refills the SR Ca2+ stores. We found that the acute decrease in contraction amplitude and increase in diastolic sarcomere length were unaffected by pretreatment with thapsigargin to attenuate SERCA activity. Interestingly, however, the recovery of depressed myocyte contractility during sustained acetate exposure and the abrupt increase in contraction amplitude due to acetate removal were no longer observed when cells were pretreated with thapsigargin. One possible explanation of this phenomenon is that inhibition of SR Ca2+ store replenishment prevents the restoration of fractional shortening.
Acetate effects on mitochondria
Mitochondrial uptake of acetate has been shown to be coupled with increases in Ca2+ uptake and swelling . It was proposed that direct transport of phosphate or anions of weak acids like acetate can permeate the mitochondrial membrane generatings a driving force for Ca2+ uptake into the mitochondrial matrix. Similar observations demonstrate that acetate or phosphate increase the rate of mitochondrial Ca2+ uptake in a concentration dependent manner  and that acetate increases mitochondrial Ca2+ uptake in heart mitochondria . The data in the present study do not delineate the molecular transporters mediating Ca2+ entry into the mitochondria. In addition to the mitochondrial Ca2+ uniporter , the mitochondrial ryanodine receptor (mRyr) , or Ca2+/H+ exchanger (Letm1)  could play a role in the acetate-induced increase in mitochondrial Ca2+. Nevertheless, here we present pharmacological evidence showing that acetate is apparently coupled with an increase in mitochondrial Ca2+ in isolated cardiac myocytes and it is plausible to assume that this decreases the amount of Ca2+ available for contraction.
In isolated mitochondria, acetate also caused osmotic swelling . Given the tight interfibrillar packing of mitochondria in the heart ,, acetate associated mitochondrial swelling might also be linked to the observed increase in diastolic sarcomere length. Interestingly, the effect of acetate on diastolic sarcomere length, unlike the effect on contraction, is sustained throughout acetate exposure and shows little concentration dependence. This observation is consistent with the conclusion that acetate causes the mitochondria to swell increasing the sarcomere spacing. While active cell shortening recovers as the SR refills with Ca2+, the mitochondria remain swollen and the increased diastolic sarcomere length is maintained. Given the structural constraints, it seems possible that swelling is physically limited possibly explaining the absence of a clear concentration dependence.
The observed delay from acetate application to initial effects on contraction is similar to the time course for conversion of acetate to acetyl CoA observed by Randle . Acetate has been shown to decrease the phosphorylation potential  resulting in decreased free energy from ATP hydrolysis; since the demand likely remains constant, the cell must increase the rate of respiration to cover the difference. This might suggest that acetate oxidation increases mitochondrial respiration with concomitant increases in mitochondrial Ca2+. However, this is very unlikely since substrate availability governs only the pathways used to generate ATP, while workload or demand is the principal determinant of respiration ,. In unloaded myocytes paced at a constant frequency, it is expected that the workload is constant; therefore, it is unlikely that acetate-induced changes in respiration underlie the increase in mitochondrial Ca2+ uptake. Rather, we consider the possibility that mitochondrial uptake of the acetate anion is electrically balanced by the uptake of Ca2+ in line with the conclusion of others based on experiments with isolated mitochondria -.
Short chain fatty acids like acetate and butyrate may also cause changes in intracellular pH with effects on contraction and SR Ca2+ content ,. The current data do not preclude a role for cytoplasm acidification in the effect of acetate on myocyte contraction. However, the observations that acetate increases mitochondrial Ca2+ and that pretreatment of cells with Ru-360 markedly attenuates the effects of acetate argues that an acute change in mitochondrial Ca2+ uptake, rather than cytoplasmic acidification, is the predominant mechanism underlying the effects of acetate on contraction. Moreover, it is tempting to predict that other anions of weak organic acids (e.g. lactate, butyrate, or pyruvate) may cause similar changes.
Mitochondrial Ca2+ uptake and cardiovascular disease
In the heart, mitochondrial Ca2+ uptake has been proposed as an important player in regulating cardiac energetics, reactive oxygen species generation and supply–demand matching ,; however, mitochondrial Ca2+ overload is also associated with the activation of cell death pathways . Thus a balance in mitochondrial Ca2+ loading is required in order to achieve proper regulation of metabolism, but avoid overloading and cell death. In ischemia-reperfusion experiments, excessive Ca2+ uptake is associated with a poor outcome, and treatment with Ru-360 to inhibit mitochondrial Ca2+ uptake is beneficial . Acetate in this setting would be predicted to have no effect or be detrimental, and this has been shown to be the case ,-. Conversely, the failing heart has been shown to have reduced mitochondrial Ca2+ resulting from increases in cytosolic Na+ concentrations and increased mitochondrial sodium-calcium exchange activity and blocking mitochondrial Ca2+ export (i.e. enhancing mitochondrial Ca2+) is beneficial . The data in the present study suggest that elevating circulating acetate might be an alternative strategy to accomplish this goal, although it should be noted that the study presented here was focused on the transient and not steady state consequences of acetate.
In summary, we have shown that acetate causes an acute but transient reduction in contractile function in isolated cardiac myocytes. Mechanistically, the transient negative inotropic effect appears to result from an acetate-dependent increase in mitochondrial Ca2+ uptake. This finding is consistent with the results of Lehninger and others using isolated liver and heart mitochondria, where it has been shown that acetate causes an increase in mitochondrial Ca2+ uptake and osmotic swelling -. Here we show that this effect appears to extend into intact, hydraulically unloaded cardiomyocytes, possibly suggesting a novel way to modulate mitochondrial Ca2+ homeostasis in the intact heart in vivo.
This work was supported by funding from the Henry M. Jackson Foundation (to TPF) and the Department of Defense (R0702O to TPF).
The views expressed are those of the authors and do not reflect the official policy or position of the Uniformed Services University of the Health Sciences, the Department of the Defense, or the United States governmen.
- Flagg TP, Cazorla O, Remedi MS, Haim TE, Tones MA, Bahinski A, Numann RE, Kovacs A, Schaffer JE, Nichols CG, Nerbonne JM: Ca2 + −independent alterations in diastolic sarcomere length and relaxation kinetics in a mouse model of lipotoxic diabetic cardiomyopathy. Circ Res 2009,104(1):95-103. 10.1161/CIRCRESAHA.108.186809View ArticlePubMedGoogle Scholar
- Haim TE, Wang W, Flagg TP, Tones MA, Bahinski A, Numann RE, Nichols CG, Nerbonne JM: Palmitate attenuates myocardial contractility through augmentation of repolarizing Kv currents. J Mol Cell Cardiol 2010,48(2):395-405. 10.1016/j.yjmcc.2009.10.004View ArticlePubMedPubMed CentralGoogle Scholar
- Martin BJ, Valdivia HH, Bunger R, Lasley RD, Mentzer RM Jr: Pyruvate augments calcium transients and cell shortening in rat ventricular myocytes. Am J Physiol 1998,274(1 Pt 2):H8-H17.PubMedGoogle Scholar
- Kirkendol PL, Pearson JE, Bower JD, Holbert RD: Myocardial depressant effects of sodium acetate. Cardiovasc Res 1978,12(2):127-136. 10.1093/cvr/12.2.127View ArticlePubMedGoogle Scholar
- Jacob AD, Elkins N, Reiss OK, Chan L, Shapiro JI: Effects of acetate on energy metabolism and function in the isolated perfused rat heart. Kidney Int 1997,52(3):755-760. 10.1038/ki.1997.392View ArticlePubMedGoogle Scholar
- Liang CS, Lowenstein JM: Metabolic control of the circulation. Effects of acetate and pyruvate. J Clin Invest 1978,62(5):1029-1038. 10.1172/JCI109207View ArticlePubMedPubMed CentralGoogle Scholar
- Ballard FJ: Supply and utilization of acetate in mammals. Am J Clin Nutr 1972,25(8):773-779.PubMedGoogle Scholar
- Skutches CL, Holroyde CP, Myers RN, Paul P, Reichard GA: Plasma acetate turnover and oxidation. J Clin Invest 1979,64(3):708-713. 10.1172/JCI109513View ArticlePubMedPubMed CentralGoogle Scholar
- Fujino T, Kondo J, Ishikawa M, Morikawa K, Yamamoto TT: Acetyl-CoA synthetase 2, a mitochondrial matrix enzyme involved in the oxidation of acetate. J Biol Chem 2001,276(14):11420-11426. 10.1074/jbc.M008782200View ArticlePubMedGoogle Scholar
- Randle PJ, England PJ, Denton RM: Control of the tricarboxylate cycle and its interactions with glycolysis during acetate utilization in rat heart. Biochem J 1970,117(4):677-695.View ArticlePubMedPubMed CentralGoogle Scholar
- Williamson JR: Effects of insulin and starvation on the metabolism of acetate and pyruvate by the perfused rat heart. Biochem J 1964,93(1):97-106.View ArticlePubMedPubMed CentralGoogle Scholar
- Taegtmeyer H, Hems R, Krebs HA: Utilization of energy-providing substrates in the isolated working rat heart. Biochem J 1980,186(3):701-711.View ArticlePubMedPubMed CentralGoogle Scholar
- Lehninger AL: Role of phosphate and other proton-donating anions in respiration-coupled transport of Ca2+ by mitochondria. Proc Natl Acad Sci U S A 1974,71(4):1520-1524. 10.1073/pnas.71.4.1520View ArticlePubMedPubMed CentralGoogle Scholar
- Reed KC, Bygrave FL: A kinetic study of mitochondrial calcium transport. Eur J Biochem 1975,55(3):497-504. 10.1111/j.1432-1033.1975.tb02187.xView ArticlePubMedGoogle Scholar
- Harris EJ: Anion/calcium ion ratios and proton production in some mitochondrial calcium ion uptakes. Biochem J 1978,176(3):983-991.View ArticlePubMedPubMed CentralGoogle Scholar
- Flagg TP, Charpentier F, Manning-Fox J, Remedi MS, Enkvetchakul D, Lopatin A, Koster J, Nichols C: Remodeling of excitation-contraction coupling in transgenic mice expressing ATP-insensitive sarcolemmal K-ATP channels. Am J Physiol Heart Circ Physiol 2004,286(4):H1361-H1369. 10.1152/ajpheart.00676.2003View ArticlePubMedGoogle Scholar
- Pan X, Liu J, Nguyen T, Liu C, Sun J, Teng Y, Fergusson MM, Rovira II, Allen M, Springer DA, Aponte AM, Gucek M, Balaban RS, Murphy E, Finkel T: The physiological role of mitochondrial calcium revealed by mice lacking the mitochondrial calcium uniporter. Nat Cell Biol 2013,15(12):1464-1472. 10.1038/ncb2868View ArticlePubMedPubMed CentralGoogle Scholar
- Miyata H, Silverman HS, Sollott SJ, Lakatta EG, Stern MD, Hansford RG: Measurement of mitochondrial free Ca2+ concentration in living single rat cardiac myocytes. Am J Physiol 1991,261(4 Pt 2):H1123-H1134.PubMedGoogle Scholar
- Matlib MA, Zhou Z, Knight S, Ahmed S, Choi KM, Krause-Bauer J, Phillips R, Altschuld R, Katsube Y, Sperelakis N, Bers DM: Oxygen-bridged dinuclear ruthenium amine complex specifically inhibits Ca2+ uptake into mitochondria in vitroand in situ in single cardiac myocytes. J Biol Chem 1998,273(17):10223-10231. 10.1074/jbc.273.17.10223View ArticlePubMedGoogle Scholar
- Zhou Z, Bers D: Time course of action of antagonists of mitochondrial Ca uptake in intact ventricular myocytes. Pflugers Arch 2002,445(1):132-138. 10.1007/s00424-002-0909-7View ArticlePubMedGoogle Scholar
- Bode EF, Briston SJ, Overend CL, O’Neill SC, Trafford AW, Eisner DA: Changes of SERCA activity have only modest effects on sarcoplasmic reticulum Ca2+ content in rat ventricular myocytes. J Physiol 2011,589(19):4723-4729. 10.1113/jphysiol.2011.211052View ArticlePubMedPubMed CentralGoogle Scholar
- Marchi S, Pinton P: The mitochondrial calcium uniporter complex: molecular components, structure and physiopathological implications. J Physiol 2014,592(Pt 5):829-839. 10.1113/jphysiol.2013.268235View ArticlePubMedPubMed CentralGoogle Scholar
- Beutner G, Sharma VK, Giovannucci DR, Yule DI, Sheu SS: Identification of a ryanodine receptor in rat heart mitochondria. J Biol Chem 2001,276(24):21482-21488. 10.1074/jbc.M101486200View ArticlePubMedGoogle Scholar
- Jiang D, Zhao L, Clapham DE: Genome-Wide RNAi Screen Identifies Letm1 as a Mitochondrial Ca2+/H+ Antiporter. Science 2009,326(5949):144-147. 10.1126/science.1175145View ArticlePubMedPubMed CentralGoogle Scholar
- Lukyanenko V, Chikando A, Lederer WJ: Mitochondria in cardiomyocyte Ca2+ signaling. Int J Biochem Cell Biol 2009,41(10):1957-1971. 10.1016/j.biocel.2009.03.011View ArticlePubMedPubMed CentralGoogle Scholar
- Ong S-B, Hausenloy DJ: Mitochondrial morphology and cardiovascular disease. Cardiovasc Res 2010,88(1):16-29. 10.1093/cvr/cvq237View ArticlePubMedPubMed CentralGoogle Scholar
- Kang YH, Mallet RT, Bunger R: Coronary autoregulation and purine release in normoxic heart at various cytoplasmic phosphorylation potentials: disparate effects of adenosine. Pflugers Arch 1992,421(2–3):188-199. 10.1007/BF00374826View ArticlePubMedGoogle Scholar
- Neely JR, Denton RM, England PJ, Randle PJ: The effects of increased heart work on the tricarboxylate cycle and its interactions with glycolysis in the perfused rat heart. Biochem J 1972,128(1):147-159.View ArticlePubMedPubMed CentralGoogle Scholar
- Bountra C, Vaughan-Jones RD: Effect of intracellular and extracellular pH on contraction in isolated, mammalian cardiac muscle. J Physiol 1989, 418: 163-187. 10.1113/jphysiol.1989.sp017833View ArticlePubMedPubMed CentralGoogle Scholar
- O’Neill SC, Eisner DA: pH-dependent and -independent effects inhibit Ca2 + −induced Ca2+ release during metabolic blockade in rat ventricular myocytes. J Physiol 2003,550(2):413-418. 10.1113/jphysiol.2003.042846View ArticlePubMedPubMed CentralGoogle Scholar
- Balaban RS: Cardiac energy metabolism homeostasis: role of cytosolic calcium. J Mol Cell Cardiol 2002,34(10):1259-1271. 10.1006/jmcc.2002.2082View ArticlePubMedGoogle Scholar
- Liu T, O’Rourke B: Regulation of mitochondrial Ca2+ and its effects on energetics and redox balance in normal and failing heart. J Bioenerg Biomembr 2009,41(2):127-132. 10.1007/s10863-009-9216-8View ArticlePubMedPubMed CentralGoogle Scholar
- Garcia-Dorado D, Ruiz-Meana M, Inserte J, Rodriguez-Sinovas A, Piper HM: Calcium-mediated cell death during myocardial reperfusion. Cardiovasc Res 2012,94(2):168-180. 10.1093/cvr/cvs116View ArticlePubMedGoogle Scholar
- Garcia-Rivas Gde J, Carvajal K, Correa F, Zazueta C: Ru360, a specific mitochondrial calcium uptake inhibitor, improves cardiac post-ischaemic functional recovery in rats in vivo. Br J Pharmacol 2006,149(7):829-837. 10.1038/sj.bjp.0706932View ArticlePubMedGoogle Scholar
- Mallet RT, Sun J, Knott EM, Sharma AB, Olivencia-Yurvati AH: Metabolic cardioprotection by pyruvate: recent progress. Exp Biol Med (Maywood) 2005,230(7):435-443.Google Scholar
- Bunger R, Mallet RT: Mitochondrial pyruvate transport in working guinea-pig heart. Work-related vs carrier-mediated control of pyruvate oxidation. Biochim Biophys Acta 1993,1151(2):223-236. 10.1016/0005-2736(93)90107-BView ArticlePubMedGoogle Scholar
- Bunger R, Mallet RT, Hartman DA: Pyruvate-enhanced phosphorylation potential and inotropism in normoxic and postischemic isolated working heart. Near-complete prevention of reperfusion contractile failure. Eur J Biochem 1989,180(1):221-233. 10.1111/j.1432-1033.1989.tb14637.xView ArticlePubMedGoogle Scholar
- Liu T, O’Rourke B: Enhancing mitochondrial Ca2+ uptake in myocytes from failing hearts restores energy supply and demand matching. Circ Res 2008,103(3):279-288. 10.1161/CIRCRESAHA.108.175919View ArticlePubMedPubMed CentralGoogle Scholar
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