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Oxygen dependence of mitochondrial function in isolated rat cardiac myocytes.
Am J Physiol 1986; 250(3 Pt 1):C374-83AJ

Abstract

The O2 dependence of respiratory functions was studied in suspensions of isolated rat cardiac myocytes. Direct optical spectroscopy of the oxidation of cytochromes and oxygenation of Mb showed that cytochrome alpha 3 oxidation measured at 445-460 nm parallels Mb oxygenation; half-maximal values were at 8.0 and 8.5 microM, respectively. Thus there appears to be a close functional relationship between these components in the cells. The values are very high relative to comparable values for cytochrome alpha 3 oxidation in isolated rat heart mitochondria under state 3 conditions (0.43 microM) and isolated rat heart Mb (2.8 microM). Moreover, the measured values for half-maximal oxidation of cytochromes and oxygenation of Mb in the cells are sensitive to factors that alter the O2 consumption rate of the cells. These results indicate that mitochondrial respiration results in establishment of a gradient of O2 concentration from the suspending medium to the mitochondrial inner membrane. A portion of this gradient is between the suspending medium and the region occupied by Mb, and the remainder is between the region occupied by Mb and the inner mitochondrial membrane. The intracellular O2 gradient is an important factor in determining the O2 dependence of mitochondria in cells and hence may contribute to the O2 dependence of cardiac myocyte function in vivo.

Authors

No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

3953808

Citation

Kennedy, F G., and D P. Jones. "Oxygen Dependence of Mitochondrial Function in Isolated Rat Cardiac Myocytes." The American Journal of Physiology, vol. 250, no. 3 Pt 1, 1986, pp. C374-83.
Kennedy FG, Jones DP. Oxygen dependence of mitochondrial function in isolated rat cardiac myocytes. Am J Physiol. 1986;250(3 Pt 1):C374-83.
Kennedy, F. G., & Jones, D. P. (1986). Oxygen dependence of mitochondrial function in isolated rat cardiac myocytes. The American Journal of Physiology, 250(3 Pt 1), pp. C374-83.
Kennedy FG, Jones DP. Oxygen Dependence of Mitochondrial Function in Isolated Rat Cardiac Myocytes. Am J Physiol. 1986;250(3 Pt 1):C374-83. PubMed PMID: 3953808.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Oxygen dependence of mitochondrial function in isolated rat cardiac myocytes. AU - Kennedy,F G, AU - Jones,D P, PY - 1986/3/1/pubmed PY - 1986/3/1/medline PY - 1986/3/1/entrez SP - C374 EP - 83 JF - The American journal of physiology JO - Am. J. Physiol. VL - 250 IS - 3 Pt 1 N2 - The O2 dependence of respiratory functions was studied in suspensions of isolated rat cardiac myocytes. Direct optical spectroscopy of the oxidation of cytochromes and oxygenation of Mb showed that cytochrome alpha 3 oxidation measured at 445-460 nm parallels Mb oxygenation; half-maximal values were at 8.0 and 8.5 microM, respectively. Thus there appears to be a close functional relationship between these components in the cells. The values are very high relative to comparable values for cytochrome alpha 3 oxidation in isolated rat heart mitochondria under state 3 conditions (0.43 microM) and isolated rat heart Mb (2.8 microM). Moreover, the measured values for half-maximal oxidation of cytochromes and oxygenation of Mb in the cells are sensitive to factors that alter the O2 consumption rate of the cells. These results indicate that mitochondrial respiration results in establishment of a gradient of O2 concentration from the suspending medium to the mitochondrial inner membrane. A portion of this gradient is between the suspending medium and the region occupied by Mb, and the remainder is between the region occupied by Mb and the inner mitochondrial membrane. The intracellular O2 gradient is an important factor in determining the O2 dependence of mitochondria in cells and hence may contribute to the O2 dependence of cardiac myocyte function in vivo. SN - 0002-9513 UR - https://www.unboundmedicine.com/medline/citation/3953808/Oxygen_dependence_of_mitochondrial_function_in_isolated_rat_cardiac_myocytes_ L2 - http://www.physiology.org/doi/full/10.1152/ajpcell.1986.250.3.C374?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -