Linked Life Data

8048646

Source:http://linkedlifedata.com/resource/pubmed/id/8048646

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1 Pt 2
pubmed:dateCreated
1994-9-1
pubmed:abstractText
Active salmonids maintain myocardial contractility at temperatures that are cardioplegic for mammals. We postulated that myofibrillar Ca2+ sensitivity in the trout heart might 1) exhibit lower temperature dependence and/or 2) be greater over the range of physiological temperatures. Temperature-induced changes in intracellular pH may also play a role as alkalosis typically increases calcium affinity of myofibrillar adenosinetriphosphatase (ATPase). Ca2+ sensitivities of ventricular myofibrillar ATPase were determined in rats and in rainbow trout (Oncorhynchus mykiss) over a physiological range of pH and temperatures. Maximal myofibrillar ATPase activities of each species were similar and equally affected by temperature. Trout myofibrillar ATPase lost Ca2+ dependence at 37 degrees C. At constant pH, reduced temperature decreased calcium affinity more in trout (0.35 pCa/10 degrees C) than in rat (0.08-0.16 pCa/10 degrees C). Under alpha-stat conditions, the effects of temperature were reduced in both trout (0.2 pCa/10 degrees C) and rat (no significant effect). Over trout physiological temperatures, Ca2+ sensitivity was greater than rat at 37 degrees C. Qualitatively similar results were observed in studies measuring tension in skinned trout ventricular fibers. One mechanism by which the trout heart is able to maintain contractility at low temperatures is through the inherent higher Ca2+ sensitivity of the contractile element compared with mammalian species.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0002-9513
pubmed:author
pubmed:issnType
Print
pubmed:volume
267
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
R62-70
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Temperature and pH effects on Ca2+ sensitivity of cardiac myofibrils: a comparison of trout with mammals.
pubmed:affiliation
Cardiac Membrane Research Laboratory, Simon Fraser University, Burnaby, British Columbia, Canada.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't