Linked Life Data

18508728

Source:http://linkedlifedata.com/resource/pubmed/id/18508728

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:dateCreated
2008-5-29
pubmed:abstractText
Stretch induces biphasic inotropic effects in mammalian myocardium. A delayed component (slow force response, SFR) has been demonstrated in various species, however, experimental conditions varied and the underlying mechanisms are controversial. The physiological relevance of the SFR is poorly understood. Experiments were performed in ventricular muscle strips from failing human hearts and non-failing rabbit hearts. Upon stretch, twitch force was assessed at basal conditions (1 Hz, 37 degrees C) and after changing stimulation frequency with and without blockade of the Na+/H+-exchanger-1 (NHE1) or reverse-mode Na+/Ca2+-exchange (NCX). Action potential duration (APD) was assessed using floating electrodes. Low stimulation rates (0.2 Hz) potentiated and higher stimulation rates (2 and 3 Hz) reduced the SFR. The extent of SFR inhibition by NHE1 or NCX inhibition was not affected by stimulation rate. APD decreased at 0.2 Hz but was not altered at higher stimulation rates. The data demonstrate frequency-dependence of the SFR with greater positive inotropic effects at lower stimulation rates. Subcellular mechanisms underlying the SFR are not fundamentally affected by stimulation rate. The SFR may have more pronounced physiological effects at lower heart rates.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:issn
1093-4715
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
13
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
7202-9
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Frequency-dependence of the slow force response.
pubmed:affiliation
Department of Cardiology, Medical University Graz, Austria.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't