Calcium Ion-Induced Loss of Respiratory Control in Rat Liver Mitochondria in the Presence of Inhalational Anaesthetic Agents

1973 ◽  
Vol 1 (4) ◽  
pp. 854-857 ◽  
Author(s):  
G. M. HALL ◽  
S. J. KIRTLAND ◽  
E. M. GRIST ◽  
H. BAUM
Keyword(s):  
Rat Liver ◽  
Calcium Ion ◽  
Respiratory Control ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria ◽  
Anaesthetic Agents ◽  
Inhalational Anaesthetic

scholarly journals The nature of the calcium ion efflux induced in rat liver mitochondria by the oxidation of endogenous nicotinamide nucleotides

1980 ◽  
Vol 188 (1) ◽  
pp. 113-118 ◽  
Author(s):  
D G Nicholls ◽  
M D Brand
Keyword(s):  
Membrane Potential ◽  
Rat Liver ◽  
Calcium Ion ◽  
Respiratory Control ◽  
Liver Mitochondria ◽  
Critical Value ◽  
Mitochondrial Damage ◽  
Rat Liver Mitochondria ◽  
Ion Efflux ◽  
Complete Collapse

Ca2+ efflux from rat liver mitochondria can occur when endogenous nicotinamide nucleotides are oxidized. It is suggested that nicotinamide nucleotide induced by acetoacetate sensitizes the mitochondria to damaage resulting from the accumulation of Ca2+ in the presence of Pi. Thus, acetoacetate-induced Ca2+ efflux is associated with a loss of respiratory control. Both the effluxes induced by acetoacetate and by high Ca2+ accumulation are prevented by ATP plus oligomycin, although these agents do not prevent the endoagenous nicotinamide nucleotides from becoming oxidized on addition of acetoacetate. Acetoacetate addition only results in Ca2+ release if the Ca2+ and Pi concentration are above a critical value. The acetoacetate-induced Ca2+ effflux is exactly paralled by the virtually complete collapse of the membrane potential. The presence of acetoacetate decreases the concentration of total Ca2+ necessary to induced mitochondrial damage by about 130 nmol of Ca2+/mg of protein. It is concluded that acetoacetate-induced efflux occurs by reversal of the Ca2+ uniporter after the collapse of the membrane potential.

Mechanism of sodium ion independent calcium ion efflux from rat liver mitochondria

Biochemistry ◽  
1983 ◽  
Vol 22 (26) ◽  
pp. 6341-6351 ◽  
Author(s):  
T. E. Gunter ◽  
J. H. Chace ◽  
J. S. Puskin ◽  
K. K. Gunter
Keyword(s):  
Rat Liver ◽  
Calcium Ion ◽  
Liver Mitochondria ◽  
Sodium Ion ◽  
Rat Liver Mitochondria ◽  
Ion Efflux

scholarly journals Effect of micromolar concentrations of manganese ions on calcium-ion cycling in rat liver mitochondria

1983 ◽  
Vol 212 (3) ◽  
pp. 773-782 ◽  
Author(s):  
B P Hughes ◽  
J H Exton
Keyword(s):  
Rat Liver ◽  
Calcium Ion ◽  
Incubation Medium ◽  
Liver Mitochondria ◽  
Ruthenium Red ◽  
Rat Liver Mitochondria ◽  
Manganese Ions ◽  
Dose Dependent Decrease ◽  
Incubation Temperatures ◽  
Dose Dependent

The effects of micromolar concentrations of Mn2+ on the rat liver mitochondrial Ca2+ cycle were investigated. It was found that the addition of Mn2+ to mitochondria which were cycling 45Ca2+ led to a rapid dose dependent decrease in the concentration of extramitochondrial 45Ca2+ of about 1 nmol/mg of protein. The effect was complete within 30 s, was half maximal with 10 microM Mn2+ and was observed in the presence of 3 mM Mg2+ and 1 mM ATP. It occurred over a broad range of incubation temperatures, pH and mitochondrial Ca2+ loads. It was not observed when either Mg2+ or phosphate was absent from the incubation medium, or in the presence of Ruthenium Red. These findings indicate that micromolar concentrations of Mn2+ stimulate the uptake of Ca2+ by rat liver mitochondria, and provide evidence for an interaction between Mg2+ and Mn2+ in the control of mitochondrial Ca2+ cycling.

scholarly journals The maturation of the inner membrane of foetal rat liver mitochondria. An example of a positive-feedback mechanism

1975 ◽  
Vol 150 (3) ◽  
pp. 477-488 ◽  
Author(s):  
J K Pollak
Keyword(s):  
Oxidative Phosphorylation ◽  
Rat Liver ◽  
Mitochondrial Membrane ◽  
Respiratory Control ◽  
Liver Mitochondria ◽  
Neonatal Rat ◽  
Rat Liver Mitochondria ◽  
Inner Mitochondrial Membrane ◽  
Mature Adult ◽  
Foetal Rat

A new method was devised for the isolation of foetal and neonatal rat lvier mitochondria, giving higher yields than conventional methods. 2. During development from the perinatal period to the mature adult, the ratio of cytochrome oxidase/succinate-cytochrome c reductase changes. 3. The inner mitochondrial membrane of foetal liver mitochondria possesses virtually no osmotic activity; the permeability to sucrose decreases with increasing developmental age. 4. Foetal rat liver mitochondria possess only marginal respiratory control and do not maintain Ca2+-induced respiration; they also swell in respiratory-control medium in the absence of substrate. ATP enhances respiratory control and prevents swelling, adenylyl imidodiphosphate, ATP+atractyloside enhance the R.C.I. (respiratory control index), Ca2+-induced respiratory control and prevent swelling, whereas GTP and low concentrations of ADP have none of these actions. It is concluded that the effect of ATP depends on steric interaction with the inner mitochondrial membrane. 5. When 1-day pre-partum foetuses are obtained by Caesarean section and maintained in a Humidicrib for 90 min, mitochondrial maturation is ‘triggered’, so that their R.C.I. is enhanced and no ATP is required to support Ca2+-dependent respiratory control or to inhibit mitochondrial swelling. 6. It is concluded that foetal rat liver mitochondria in utero do not respire, although they are capable of oxidative phosphorylation in spite of their low R.C.I. The different environmental conditions which the neonatal rat encounters ex utero enable the hepatic mitochondria to produce ATP, which interacts with the inner mitochondrial membrane to enhance oxidative phosphorylation by an autocatalytic mechanism.

scholarly journals Transport of reduced nicotinamide–adenine dinucleotide into mitochondria of rat white adipose tissue

1970 ◽  
Vol 116 (2) ◽  
pp. 229-233 ◽  
Author(s):  
B. H. Robinson ◽  
M. L. Halperin
Keyword(s):  
Adipose Tissue ◽  
Rat Liver ◽  
White Adipose Tissue ◽  
Nicotinamide Adenine Dinucleotide ◽  
Aspartate Aminotransferase ◽  
Respiratory Control ◽  
Liver Mitochondria ◽  
Nadh Oxidation ◽  
Rat Liver Mitochondria ◽  
Reduced Nicotinamide Adenine Dinucleotide

Mitochondria from rat white adipose tissue were prepared, exhibiting good respiratory control and P/O ratios. They would not oxidize NADH unless NNN′N′-tetramethyl-p-phenylenediamine was added as a carrier of reducing equivalents. These mitochondria were found to oxidize neither l-glycerol 3-phosphate nor l-glutamate plus l-malate at significant rates. The activity of aspartate aminotransferase in these mitochondria was found to be low compared with that found in rat liver mitochondria. As a consequence of this, the adipose-tissue mitochondria exhibited very low rates of cytoplasmic NADH oxidation in a reconstituted Borst (1962) cycle compared with liver mitochondria.

Uncoupling activity of endogenous free fatty acids in rat liver mitochondria

1978 ◽  
Vol 56 (2) ◽  
pp. 111-116 ◽  
Author(s):  
Samuel H. P. Chan ◽  
Edward Higgins Jr.
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Free Fatty Acids ◽  
Rat Liver ◽  
Respiratory Control ◽  
Aging Effect ◽  
Liver Mitochondria ◽  
Rat Liver Mitochondria

Changes in the respiratory control index (RCI) and ADP:O ratio were found to be related to alterations in the free fatty acids levels of rat liver mitochondria aging in 0.25 M sucrose–Tris buffer at 0 °C. Free fatty acid levels increased with time after isolation of mitochondria while a concomitant decrease in the RCI and ADP:O ratio occurred. The changes in free fatty acid levels corresponded with the reported increasing levels of phospholipase A activity in aged mitochondrial preparations. Washing these mitochondria with sucrose buffer containing 1% defatted bovine serum albumin (BSA) counteracted the aging effect on the RCI (e.g., 2.5 to 3.5) and reduced the free fatty acid levels (e.g., 50 to 16 nmol/mg protein). This reversible phenomenon could be repeated several times during the in vitro aging at 0 °C. Use of 125I-iodinated BSA showed that approximately 5 μg BSA/mg mitochondria was adsorbed by the mitochondrial membranes during washing. These results indicate a direct correlation between the level of endogenous fatty acids and the uncoupling of mitochondrial oxidative phosphorylation. The mechanism of counteracting the aging effect by BSA involves the removal of some of the free fatty acids.

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