Linked Life Data

1834872

Source:http://linkedlifedata.com/resource/pubmed/id/1834872

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
1991-12-6
pubmed:abstractText
Reperfusion after reversible ischemia has been shown to result in prolonged depression of contractile function ("myocardial stunning"). Recent studies suggest that oxygen free radicals may mediate postischemic dysfunction. Since heart sarcolemmal membranes, which contain several types of enzymes, ion channels and receptors play important roles to maintain cell functions, the present study was undertaken to examine the effects of oxygen free radicals on heart sarcolemmal membrane functions in vitro. In the presence of a superoxide anion radical-generating system (2mM xanthine plus 0.03 U/ml xanthine oxidase), sarcolemmal Ca(2+)-stimulated ATPase activity and ATP-dependent Ca2+ accumulation were inhibited in an incubating time-dependent manner. Both lipid peroxidation (r = 0.82) and sulfhydryl group content (r = 0.95) showed significant correlations with Ca(2+)-stimulated ATPase activity. ATP-independent Ca2+ bindings were increased upon treating the membranes with xanthine plus xanthine oxidase. Voltage-dependent Ca(2+)-channels were also affected by oxygen free radicals. The maximal number of binding sites (Bmax) for [3H]-nitrendipine binding was depressed without any changes in dissociation constant (Kd). The effects of oxygen free radicals on adrenergic receptors were more complex. Bmax for [3H]-dihydroalprenolol (DHA) binding (beta-receptor) was increased whereas Bmax for [3H]-prazosin binding [alpha 1-receptor) was decreased after incubating the membrane with xanthine plus xanthine oxidase. Kd for [3H]-DHA or [3H]-prazosin binding was increased. Superoxide dismutase showed protective effects on the changes in these membrane functions due to xanthine plus xanthine oxidase. It is suggested that oxygen free radicals damage heart sarcolemmal membrane functions which may lead to cardiac dysfunction in the stunned myocardium.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0047-1828
pubmed:author
pubmed:issnType
Print
pubmed:volume
55
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
885-92
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Stunned myocardium and oxygen free radicals--sarcolemmal membrane damage due to oxygen free radicals.
pubmed:affiliation
Third Department of Internal Medicine, Hamamatsu University School of Medicine, Japan.
pubmed:publicationType
Journal Article