Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
34
pubmed:dateCreated
1997-9-15
pubmed:abstractText
Endothelial nitric-oxide synthase (eNOS) is an important regulator of endothelial function and vascular tone in biological tissues. While endothelial dysfunction occurs following ischemia and has been attributed to altered NO. formation, the biochemical basis for this dysfunction is unknown. Therefore, studies were performed to determine the effects of myocardial ischemia and reperfusion on eNOS in isolated rat hearts subjected to periods of global ischemia or ischemia followed by reperfusion. eNOS activity was assayed by L-[14C]arginine to L-[14C]citrulline conversion and alterations in the amount and distribution of eNOS determined by Western blotting and immunohistochemistry. While activity was preserved after 30 min of ischemia with a value of 1.1 +/- 0.1 pmol x min-1 x mg of protein-1, it decreased by 77% after 60 min and became nearly undetectable after 120 min. Reperfusion resulted in only a partial restoration of activity. The decline in activity with ischemia was due, in part, to a loss of eNOS protein. Hemodynamic studies showed that the onset of impaired vascular reactivity paralleled the loss of functional eNOS. Subjecting isolated eNOS to conditions of acidosis, which occur during ischemia, followed by restoration of pH as occurs on reperfusion, caused a combination of reversible and irreversible loss of activity similar to that seen in ischemic and reperfused hearts. Thus, loss of endothelial function following ischemia is paralleled by a loss of eNOS activity due to a combination of pH-dependent denaturation and proteolysis.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
22
pubmed:volume
272
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
21420-6
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Decreased nitric-oxide synthase activity causes impaired endothelium-dependent relaxation in the postischemic heart.
pubmed:affiliation
Department of Medicine, The Johns Hopkins Medical Institutions, Johns Hopkins Bayview Medical Center, Baltimore, Maryland 21224, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.