scholarly journals Modification of calcium retention capacity of rat liver mitochondria by phosphate and tert-butyl hydroperoxide

2019 ◽  
pp. 59-65 ◽  
Author(s):  
R. Endlicher ◽  
Z. Drahota ◽  
Z. Červinková
Keyword(s):  
Rat Liver ◽  
Cyclosporine A ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Retention Capacity ◽  
Butyl Hydroperoxide ◽  
Calcium Retention ◽  
Tert Butyl ◽  
Tert Butyl Hydroperoxide ◽  
Calcium Retention Capacity

By determining the calcium retention capacity (CRC) of rat liver mitochondria, we confirmed and extended previous observations describing the activation of mitochondrial swelling by phosphate and tert-butyl hydroperoxide (t-BHP). Using CRC measurements, we showed that both phosphate and t-BHP decrease the extent of calcium accumulation required for the full mitochondrial permeability transition pore (MPTP) opening to 35 % of control values and to only 15 % when both phosphate and t-BHP are present in the medium. When changes in fluorescence were evaluated at higher resolution, we observed that in the presence of cyclosporine A fluorescence values return after each Ca(2+) addition to basal values obtained before the Ca(2+) addition. This indicates that the MPTP remains closed. However, in the absence of cyclosporine A, the basal fluorescence after each Ca(2+) addition continuously increased. This increase was potentiated both by phosphate and t-BHP until the moment when the concentration of intramitochondrial calcium required for the full opening of the MPTP was reached. We conclude that in the absence of cyclosporine A, the MPTP is slowly opened after each Ca(2+) addition and that this rate of opening can be modified by various factors such as the composition of the media and the experimental protocol used.

scholarly journals Effects of Epigallocatechin Gallate on Tert-Butyl Hydroperoxide-Induced Mitochondrial Dysfunction in Rat Liver Mitochondria and Hepatocytes

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Vojtech Mezera ◽  
Rene Endlicher ◽  
Otto Kucera ◽  
Ondrej Sobotka ◽  
Zdenek Drahota ◽  
...  
Keyword(s):  
Mitochondrial Dysfunction ◽  
Rat Liver ◽  
Epigallocatechin Gallate ◽  
Rat Hepatocytes ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Retention Capacity ◽  
Butyl Hydroperoxide ◽  
Tert Butyl ◽  
Tert Butyl Hydroperoxide

Epigallocatechin gallate (EGCG) is a green tea antioxidant with adverse effects on rat liver mitochondria and hepatocytes at high doses. Here, we assessed whether low doses of EGCG would protect these systems from damage induced by tert-butyl hydroperoxide (tBHP). Rat liver mitochondria or permeabilized rat hepatocytes were pretreated with EGCG and then exposed to tBHP. Oxygen consumption, mitochondrial membrane potential (MMP), and mitochondrial retention capacity for calcium were measured. First, 50 μM EGCG or 0.25 mM tBHP alone increased State 4 Complex I-driven respiration, thus demonstrating uncoupling effects; tBHP also inhibited State 3 ADP-stimulated respiration. Then, the coexposure to 0.25 mM tBHP and 50 μM EGCG induced a trend of further decline in the respiratory control ratio beyond that observed upon tBHP exposure alone. EGCG had no effect on MMP and no effect, in concentrations up to 50 μM, on mitochondrial calcium retention capacity. tBHP led to a decline in both MMP and mitochondrial retention capacity for calcium; these effects were not changed by pretreatment with EGCG. In addition, EGCG dose-dependently enhanced hydrogen peroxide formation in a cell- and mitochondria-free medium.Conclusion. Moderate nontoxic doses of EGCG were not able to protect rat liver mitochondria and hepatocytes from tBHP-induced mitochondrial dysfunction.

Tert-butyl hydroperoxide-induced radical production in rat liver mitochondria

1992 ◽  
Vol 12 (5) ◽  
pp. 381-387 ◽  
Author(s):  
Christopher H. Kennedy ◽  
Daniel F. Church ◽  
Gary W. Winston ◽  
William A. Pryor
Keyword(s):  
Rat Liver ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Butyl Hydroperoxide ◽  
Tert Butyl ◽  
Radical Production ◽  
Tert Butyl Hydroperoxide

scholarly journals Factors Affecting the Function of the Mitochondrial Membrane Permeability Transition Pore and Their Role in Evaluation of Calcium Retention Capacity Values

2020 ◽  
pp. 491-499
Author(s):  
Z DRAHOTA ◽  
R ENDLICHER ◽  
O KUČERA ◽  
D RYCHTRMOC ◽  
Z ČERVINKOVÁ
Keyword(s):  
Mitochondrial Permeability Transition ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Experimental Conditions ◽  
Protein Ratio ◽  
Retention Capacity ◽  
Calcium Retention ◽  
Calcium Retention Capacity

Values of the calcium retention capacity (CRC) of rat liver mitochondria are highly dependent on the experimental conditions used. When increasing amounts of added calcium chloride are used (1.25-10 nmol), the values of the CRC increase 3-fold. When calcium is added in 75 s intervals, the CRC values increase by 30 % compared with 150 s interval additions. CRC values are not dependent on the calcium/protein ratio in the measured sample in our experimental design. We also show that a more detailed evaluation of the fluorescence curves can provide new information about mitochondrial permeability transition pore opening after calcium is added.

scholarly journals Inhibition of Palmityl Carnitine Oxidation in Rat Liver Mitochondria by Tert-Butyl Hydroperoxide

2008 ◽  
pp. 133-136
Author(s):  
Z Červinková ◽  
H Rauchová ◽  
P Křiváková ◽  
Z Drahota
Keyword(s):  
Oxidative Damage ◽  
Respiratory Chain ◽  
Respiratory Control ◽  
Atp Synthesis ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Respiratory Chain Complexes ◽  
Butyl Hydroperoxide ◽  
Tert Butyl ◽  
Tert Butyl Hydroperoxide

Mitochondria as an energy generating cell device are very sensitive to oxidative damage. Our previous findings obtained in hepatocytes demonstrated that Complex I of the respiratory chain is more sensitive to oxidative damage than other respiratory chain complexes. We present additional data on isolated mitochondria showing that palmityl carnitine oxidation is strongly depressed at a low (200 µM) tert-butyl hydroperoxide (tBHP) concentration, while oxidation of the flavoproteindependent substrate – succinate is not affected and neither is ATP synthesis inhibited by tBHP. In the presence of tBHP, the respiratory control index for palmityl carnitine oxidation is strongly depressed, but when succinate is oxidized the respiratory control index remains unaffected. Our findings thus indicate that flavoprotein-dependent substrates could be an important nutritional factor for the regeneration process in the necrotic liver damaged by oxidative stress.

scholarly journals Oxidative damage of rat liver mitochondria during exposure to t-butyl hydroperoxide. Role of Ca2+ ions in oxidative processes

Life Sciences ◽  
2013 ◽  
Vol 92 (23) ◽  
pp. 1110-1117 ◽  
Author(s):  
Ilya B. Zavodnik ◽  
Iosif K. Dremza ◽  
Vitali T. Cheshchevik ◽  
Elena A. Lapshina ◽  
Maria Zamaraewa
Keyword(s):  
Oxidative Damage ◽  
Rat Liver ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Butyl Hydroperoxide ◽  
Oxidative Processes

scholarly journals Enhanced resistance to Ca2+-induced mitochondrial permeability transition in the long-lived red-footed tortoise Chelonoidis carbonaria

2021 ◽  
Author(s):  
Marina R. Sartori ◽  
Claudia D.C. Navarro ◽  
Roger F. Castilho ◽  
Anibal E. Vercesi
Keyword(s):  
Rat Liver ◽  
Mitochondrial Permeability Transition ◽  
Permeability Transition ◽  
Liver Mitochondria ◽  
System Capacity ◽  
Rat Liver Mitochondria ◽  
Cyclophilin D ◽  
Retention Capacity ◽  
Mitochondrial Permeability ◽  
Enhanced Resistance

The interaction between supraphysiological cytosolic Ca2+ levels and mitochondrial redox imbalance mediates the mitochondrial permeability transition (MPT). MPT is involved in cell death, diseases, and aging. This study compared the liver mitochondrial Ca2+ retention capacity and oxygen consumption in the long-lived red-footed tortoise (Chelonoidis carbonaria) to the rat as a reference standard. Mitochondrial Ca2+ retention capacity, a quantitative measure of MPT sensitivity, was remarkably higher in tortoises than rats. This difference was minimized in the presence of the MPT inhibitors, ADP and cyclosporine A. However, the Ca2+ retention capacities of tortoise and rat liver mitochondria were similar when both MPT inhibitors were present simultaneously. NADH-linked phosphorylating respiration rates of tortoise liver mitochondria represented only 30% of the maximal electron transport system capacity, indicating a limitation imposed by the phosphorylation system. These results suggested underlying differences in putative MPT structural components (e.g. ATP synthase, adenine nucleotide translocase (ANT), and cyclophilin D) between tortoises and rats. Indeed, in tortoise mitochondria, titrations of inhibitors of the oxidative phosphorylation components revealed a higher limitation of ANT. Furthermore, cyclophilin D activity was approximately 70% lower in tortoises than in rats. Investigation of critical properties of mitochondrial redox control that affect MPT demonstrated that tortoise and rat liver mitochondria exhibited similar rates of H2O2 release and glutathione redox status. Overall, our findings suggest that constraints imposed by ANT and cyclophilin D, putative components or regulators of the MPT pore, are associated with the enhanced resistance to Ca2+-induced MPT in tortoises.

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