Linked Life Data

8728117

Source:http://linkedlifedata.com/resource/pubmed/id/8728117

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1996-9-16
pubmed:abstractText
An increase in mitochondrial matrix free calcium has been shown to occur during oxygen and substrate deprivation of the perfused heart which predisposes to calcium overload and inhibition of mitochondrial function on reoxygenation. In the current study we have assessed the effect of substrate free hypoxia on mitochondrial oxygen consumption and ATP synthesis in isolated rat cardiomyocytes. Myocytes were subjected to 40 min of substrate-free hypoxia and the oxygen consumption measured together with the effects on ATP and PCr synthesis. After hypoxia myocytes showed a fall in ATP to 10% of the control value. Within 5 sec of reoxygenation the ATP level recovered to a new steady state level of 30% of the original value. The rate of oxygen consumption of hypoxic/reoxygenated cells was 3-4 fold higher than that of cells maintained under normoxic controls but in the presence of oligomycin the difference was only 1.5-fold higher, indicating a greater requirement for mitochondrial synthesis of ATP following reoxygenation. Reoxygenation in the absence of extracellular Ca2+ resulted in a lower rate of oxygen consumption (50% of the rate measured in the presence of 1 mM-Ca2+) but did not affect the steady state concentration of ATP attained 5 min after reoxygenation. These results support the idea that the increased O2 consumption of myocytes following hypoxia/reoxygenation is due to an increased demand for ATP synthesis by mitochondria and is a response to the NA+ and Ca2+ loading of the cells which occurs under these conditions. This increased demand is likely to result in a greater generation of free radicals such as superoxide by the respiratory chain which could impair cellular function over the long term.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
1071-5762
pubmed:author
pubmed:issnType
Print
pubmed:volume
24
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
159-66
pubmed:dateRevised
2003-11-14
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
Stimulation of mitochondrial oxygen consumption in isolated cardiomyocytes after hypoxia-reoxygenation.
pubmed:affiliation
Enzymology Group, Wellcome Research Laboratories, Beckenham, Kent, UK.
pubmed:publicationType
Journal Article