Influence of Pyrene on Mitochondrial Oxygen Consumption and Membrane Potential in Frogs

Abstract Background: To describe the effect of mechanical ventilation on diaphragm mitochondrial oxygen consumption, ATP production, reactive oxygen species (ROS) generation, and cytochrome-c oxidase activity and content, and their relationship to diaphragm strength in an experimental model of sepsis.Methods: A cecal ligation and puncture (CLP) protocol was performed in 12 rats while 12 controls underwent sham-operation. Half of the rats in each group were paralyzed and mechanically ventilated. We performed blood gas analysis and lactic acid assays 6 hours after surgery. Afterwards, we measured diaphragm strength and mitochondrial oxygen consumption, ATP and ROS generation, and cytochrome-c oxidase activity. We also measured malondialdehyde (MDA) content as an index of lipid peroxidation, and mRNA expression of the pro-inflammatory interleukin-1β (IL-1β) in diaphragms.Results: CLP rats showed severe hypotension, metabolic acidosis, and upregulation of diaphragm IL-1β mRNA expression. Compared to sham controls, spontaneously breathing CLP rats showed lower diaphragm force and increased susceptibility to fatigue, along with depressed mitochondrial oxygen consumption and ATP production and cytochrome-c oxidase activity. These rats also showed increased mitochondrial ROS generation and MDA content. Mechanical ventilation markedly restored mitochondrial oxygen consumption and ATP production in CLP rats; lowered mitochondrial ROS production by the complex 3; and preserved cytochrome-c oxidase activity.Conclusion: In an experimental model of sepsis, early initiation of mechanical ventilation restores diaphragm mitochondrial function.

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Effect of Captopril on Serum Lipid Levels and Cardiac Mitochondrial Oxygen Consumption in Experimentally-Induced Hypercholesterolemia in Rabbits

Physiological Research ◽

10.33549/physiolres.932177 ◽

2011 ◽

pp. S177-S184 ◽

Cited By ~ 2

Author(s):

Z. KOJIC ◽

K. GOPCEVIC ◽

D. MARINKOVIC ◽

G. TASIC

Keyword(s):

Oxygen Consumption ◽

Serum Lipid ◽

Respiratory Control ◽

Adenosine Diphosphate ◽

Lipid Levels ◽

Mitochondrial Oxygen Consumption ◽

Respiration Rates ◽

Serum Lipid Levels ◽

Hypercholesterolemic Diet ◽

Oxygen Ratio

Angiotensin converting enzyme inhibitors are widely used in therapy of cardiovascular diseases. However, the consensus on effects of these inhibitors in control of myocardial oxygen consumption during the process of experimental hypercholesterolemia and under the condition of endothelial dysfunction has not been reached. Here we examined effects of captopril, an angiotensin converting enzyme inhibitor, on serum lipid levels and oxygen consumption rate in mitochondria isolated from heart of rabbits treated by hypercholesterolemic diet. During the twelve-week period, the Chinchilla male rabbits were daily treated by saline (controls); 1 % cholesterol diet; 5 mg/kg/day captopril or 1 % cholesterol + 5 mg/kg/day captopril. Total- and high-density lipoprotein cholesterol and triglyceride in serum were measured spectrophotometricly. The left ventricle mitochondrial fraction was isolated and myocardial oxygen consumption was measured by Biological Oxygen Monitor. Mitochondria isolated from hearts of rabbits exposed to hypercholesterolemic diet showed significantly reduced respiration rates (state 3 and state 4) with altering adenosine diphosphate/oxygen ratio, whereas the respiratory control ratio was not affected when compared to controls. Mitochondria from cholesterol/captopril–treated animals showed significantly reduced respiration rates without altering adenosine diphosphate/oxygen ratio index or respiratory control ratio. Although captopril did not exert the favorable effect on serum lipid levels in cholesterol-treated animals, it restored the mitochondrial oxygen consumption. Further studies should be performed to define the underlying physiological and/or pathophysiological mechanisms and clinical implications.

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The association between cortisol, oxytocin, and immune cell mitochondrial oxygen consumption in postpartum women with childhood maltreatment

Psychoneuroendocrinology ◽

10.1016/j.psyneuen.2018.05.040 ◽

2018 ◽

Vol 96 ◽

pp. 69-77 ◽

Cited By ~ 12

Author(s):

Christina Boeck ◽

Anja Maria Gumpp ◽

Enrico Calzia ◽

Peter Radermacher ◽

Christiane Waller ◽

...

Keyword(s):

Oxygen Consumption ◽

Childhood Maltreatment ◽

Immune Cell ◽

Postpartum Women ◽

Mitochondrial Oxygen Consumption

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Mitochondrial oxyconformity and cold adaptation in the polychaete Nereis pelagica and the bivalve Arctica islandica from the Baltic and White Seas

Journal of Experimental Biology ◽

10.1242/jeb.203.21.3355 ◽

2000 ◽

Vol 203 (21) ◽

pp. 3355-3368 ◽

Cited By ~ 11

Author(s):

K. Tschischka ◽

D. Abele ◽

H.O. Portner

Keyword(s):

Oxygen Consumption ◽

Oxygen Uptake ◽

Baltic Sea ◽

White Sea ◽

Respiratory Control ◽

Tissue Level ◽

Excess Oxygen ◽

Arctica Islandica ◽

Mitochondrial Oxygen Consumption ◽

The Baltic

The rates of oxygen uptake of the marine polychaete Nereis pelagica and the bivalve Arctica islandica depend on the availability of ambient oxygen. This is manifest both at the tissue level and in isolated mitochondria studied between oxygen tensions (P(O2)) of 6.3 and 47.6 kPa (47–357 mmHg). Oxyconformity was found in both Baltic Sea (Kiel Bight) and cold-adapted White Sea populations of the two species. However, mitochondria isolated from White Sea specimens of N. pelagica and A. islandica showed a two- to threefold higher aerobic capacity than mitochondria prepared from Baltic Sea specimens. We tested whether mitochondrial oxyconformity can be explained by an additional electron pathway that is directly controlled by P(O2). Mitochondrial respiration of both invertebrate species was inhibited by cyanide (KCN) and by salicylhydroxamic acid (SHAM). The overall rate of mitochondrial oxygen consumption increased at high P(O2). Phosphorylation efficiency (ADP/O ratio) decreased at elevated P(O2) (27.5-47.6 kPa, 206–357 mmHg), regardless of whether malate or succinate was used as a substrate. In contrast to the invertebrate mitochondria studied, mitochondria isolated from bovine heart, as an oxyregulating control species, did not show an elevated rate of oxygen uptake at high P(O2) in any respiratory state, with the exception of state 2 malate respiration. In addition, rates of ATP formation, respiratory control ratios (RCR) and ADP/O ratios remained virtually unchanged or even tended to decreased. In conclusion, the comparison between mitochondria from oxyregulating and oxyconforming organisms supports the existence of an alternative oxidase in addition to the classical cytochrome c oxidase. In accordance with models discussed previously, oxidative phosphorylation does not explain the rate of mitochondrial oxygen consumption during progressive activation of the alternative electron transport system. We discuss the alternative system, thought to be adaptive in confined, usually hypoxic environments, where excess oxygen can be eliminated and oxygen levels can be kept low by an increase in the rate of oxygen consumption, thereby minimizing the risk of oxidative stress.

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