Linked Life Data

11788397

Source:http://linkedlifedata.com/resource/pubmed/id/11788397

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2002-1-14
pubmed:abstractText
The majority of studies aimed at characterizing basic contractile mechanisms have been conducted at room temperature. To elucidate the mechanism of cardiac relaxation under more physiological conditions, we investigated contractile function and calcium handling in ultrathin rat cardiac trabeculae. Active developed tension was unaltered between 22.5 and 30.0 degrees C (from 89 +/- 10 to 86 +/- 11 mN/mm(2), P = not significant) but steeply declined at 37.5 degrees C (30 +/- 5 mN/mm(2)). Meanwhile, the speed of relaxation (time from peak force to 50% relaxation) declined from 22.5 to 30.0 degrees C (from 360 +/- 40 to 157 +/- 17 ms) and further declined at 37.5 degrees C to 76 +/- 13 ms. Phase-plane analysis of calcium versus force revealed that, with increasing temperature, the relaxation phase is shifted rightward, indicating that the rate-limiting step of relaxation tends to depend more on calcium kinetics as temperature rises. The force-frequency relationship, which was slightly negative at 22.5 degrees C (0.1 vs. 1 Hz: 77 +/- 12 vs. 66 +/- 7 mN/mm(2)), became clearly positive at 37.5 degrees C (1 vs. 10 Hz: 30 +/- 5 vs. 69 +/- 9 mN/mm(2)). Phase-plane analyses indicated that, with increasing frequency, the relaxation phase is shifted leftward. We conclude that temperature independently affects contraction and relaxation, and cross-bridge cycling kinetics become rate limiting for cardiac relaxation under experimental conditions closest to those in vivo.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0363-6135
pubmed:author
pubmed:issnType
Print
pubmed:volume
282
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
H499-507
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
Myofilament properties comprise the rate-limiting step for cardiac relaxation at body temperature in the rat.
pubmed:affiliation
Institute of Molecular Cardiobiology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA. pjanssen@jhmi.edu
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't