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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1991-3-1
pubmed:abstractText
We examined the effects of the vasoconstrictor peptide endothelin-1 in isolated hearts under ischemic and cardioplegic conditions. Isolated isovolumic rat hearts were perfused with Krebs-Henseleit buffer at constant pressure. Cumulative dose-response curves were obtained for endothelin-1 boluses of 0.04-400 pmol in four groups of hearts. Coronary flow decreased with increasing dosages and was almost abolished at 400 pmol in control hearts perfused at a constant pressure of 100 mm Hg. In hearts made ischemic by reducing coronary perfusion pressure to 35 mm Hg, thus reducing coronary flow by 76%, the constrictor effect of endothelin-1 was well preserved. The endothelin-1 dose-response curve was unaltered when hearts were perfused with buffer containing 30 mM KCl to abolish mechanical activity without reducing extracellular Ca2+ concentration. A fourth group of hearts was perfused with Ca2(+)-free buffer, thus eliminating the source of extracellular Ca2+ as well as mechanical activity. In this group, the constrictor response to endothelin-1 was largely, but not completely, abolished, with a maximal constrictor effect of only 19% as opposed to 87% in control hearts. We conclude that in isolated rat heart endothelin-1 is a potent coronary constrictor under ischemic perfusion conditions and that absence of mechanical activity does not affect the action of endothelin-1, for which the presence of extracellular Ca2+ is essential. The small residual constrictor response with Ca2(+)-free perfusion is probably due to release of Ca2+ from intracellular stores.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0160-2446
pubmed:author
pubmed:issnType
Print
pubmed:volume
16
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
804-11
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
Effects of endothelin-1 in the isolated heart under ischemic and cardioplegic conditions.
pubmed:affiliation
Medizinische Universitätsklinik, Würzburg, F.R.G.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't