Difference between revisions of "Costa 1997 Am J Physiol Cell Physiol"
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|year=1997 | |year=1997 | ||
|journal=Am J Physiol Cell Physiol | |journal=Am J Physiol Cell Physiol | ||
|abstract=Respiration and oxidative phosphorylation were investigated in tightly coupled mitochondria isolated from liver and heart of rats submitted to a simulated altitude of 4,400 m for 14-15 mo and their corresponding controls at sea level. High-resolution respirometry was utilized to determine the apparent Michaelis-Menten constant for ADP and O<sub>2</sub> (K(m)-ADP and K(m)-O<sub>2</sub>, respectively), the latter under active and resting states of mitochondrial respiration. The K(m)-O<sub>2</sub> in mitochondria isolated from normoxic rats was higher for active ( | |abstract=Respiration and oxidative phosphorylation were investigated in tightly coupled mitochondria isolated from liver and heart of rats submitted to a simulated altitude of 4,400 m for 14-15 mo and their corresponding controls at sea level. High-resolution respirometry was utilized to determine the apparent Michaelis-Menten constant for ADP and O<sub>2</sub> (''K''(m)-ADP and ''K''(m)-O<sub>2</sub>, respectively), the latter under active and resting states of mitochondrial respiration. The K(m)-O<sub>2</sub> in mitochondria isolated from normoxic rats was higher for active ([[State 3]]) than for resting ([[State 4]]) respiration; the values decreased from 1.5 and 1.7 to 0.25 and 0.30 microM in heart and liver mitochondria, respectively. The ''K''(m)-O<sub>2</sub> values found in the active state suggest a role for the normally occurring intracellular ''p''O2 range reported in the literature in the regulation of cellular respiration. No changes were found in the ADP or O<sub>2</sub> dependence of respiration in the mitochondria isolated from long-term acclimatized rats compared with their controls, indicating that the intrinsic properties and the efficiency of mitochondria do not change as a consequence of adaptation to hypoxia. | ||
|mipnetlab=AR_Buenos Aires_Boveris A | |mipnetlab=AR_Buenos Aires_Boveris A | ||
|discipline=Biomedicine | |discipline=Biomedicine | ||
}} | }} | ||
{{Labeling | {{Labeling | ||
| | |area=Respiration | ||
|organism=Rat | |organism=Rat | ||
|tissues=Heart, Liver | |tissues=Heart, Liver | ||
|preparations=Isolated Mitochondria | |preparations=Isolated Mitochondria | ||
|couplingstates=OXPHOS | |injuries=Hypoxia | ||
|kinetics=ADP; Pi | |topics=Oxygen kinetics | ||
|couplingstates=LEAK, OXPHOS | |||
|substratestates=CII | |||
|kinetics=ADP; Pi | |||
|instruments=Oxygraph-2k | |||
|discipline=Biomedicine | |discipline=Biomedicine | ||
}} | }} | ||
== Discussion == | == Discussion == | ||
* Critical discussion on artificially high apparent ''p''<sub>50</sub> when measurements are made at high volume-specific flux, at OXPHOS capacity: [[Gnaiger_1998_Biochim Biophys Acta]]; [[Scandurra 2010 Adv Exp Med Biol]] | * Critical discussion on artificially high apparent ''K''(m)-O<sub>2</sub> (''p''<sub>50</sub>) when measurements are made at high volume-specific flux, at OXPHOS capacity: [[Gnaiger_1998_Biochim Biophys Acta]]; [[Scandurra 2010 Adv Exp Med Biol]]. | ||
Revision as of 06:58, 11 August 2013
| Costa LE, Méndez G, Boveris A (1997) Oxygen dependence of mitochondrial function measured by high-resolution respirometry in long-term hypoxic rats. Am J Physiol Cell Physiol 273: C852-C858. |
Costa LE, Mendez G, Boveris A (1997) Am J Physiol Cell Physiol
Abstract: Respiration and oxidative phosphorylation were investigated in tightly coupled mitochondria isolated from liver and heart of rats submitted to a simulated altitude of 4,400 m for 14-15 mo and their corresponding controls at sea level. High-resolution respirometry was utilized to determine the apparent Michaelis-Menten constant for ADP and O2 (K(m)-ADP and K(m)-O2, respectively), the latter under active and resting states of mitochondrial respiration. The K(m)-O2 in mitochondria isolated from normoxic rats was higher for active (State 3) than for resting (State 4) respiration; the values decreased from 1.5 and 1.7 to 0.25 and 0.30 microM in heart and liver mitochondria, respectively. The K(m)-O2 values found in the active state suggest a role for the normally occurring intracellular pO2 range reported in the literature in the regulation of cellular respiration. No changes were found in the ADP or O2 dependence of respiration in the mitochondria isolated from long-term acclimatized rats compared with their controls, indicating that the intrinsic properties and the efficiency of mitochondria do not change as a consequence of adaptation to hypoxia.
• O2k-Network Lab: AR_Buenos Aires_Boveris A
Labels: MiParea: Respiration
Stress:Hypoxia Organism: Rat Tissue;cell: Heart, Liver Preparation: Isolated Mitochondria"Isolated Mitochondria" is not in the list (Intact organism, Intact organ, Permeabilized cells, Permeabilized tissue, Homogenate, Isolated mitochondria, SMP, Chloroplasts, Enzyme, Oxidase;biochemical oxidation, ...) of allowed values for the "Preparation" property.
Regulation: Oxygen kinetics Coupling state: LEAK, OXPHOS
HRR: Oxygraph-2k
Discussion
- Critical discussion on artificially high apparent K(m)-O2 (p50) when measurements are made at high volume-specific flux, at OXPHOS capacity: Gnaiger_1998_Biochim Biophys Acta; Scandurra 2010 Adv Exp Med Biol.
