Linked Life Data

7762626

Source:http://linkedlifedata.com/resource/pubmed/id/7762626

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5 Pt 1
pubmed:dateCreated
1995-6-29
pubmed:abstractText
The release of sarcoplasmic reticulum (SR) Ca in cardiac muscle during excitation-contraction coupling is known to be graded by the amount of activating Ca outside the SR (i.e., Ca-induced Ca release). However, little is known about how intra-SR Ca affects the release process. In this study we assessed how the fractional SR Ca release as described by Bassani et al. [Am. J. Physiol. 265 (Cell Physiol. 34): C533-C540, 1993] is affected by alteration of trigger Ca and of SR Ca content. Experiments were done with isolated ferret ventricular myocytes using indo 1 to measure Ca concentration, perforated patch to measure Ca current (ICa), caffeine application to release SR Ca, and thapsigargin to completely block SR Ca uptake. For what we consider a Normal SR Ca load and trigger Ca [action potential at 0.5 Hz with 2 mM extracellular Ca concentration ([Ca]o)], 35 +/- 3% of the SR Ca content was released at a twitch. Changing trigger Ca by altering [Ca]o (to 0.5 and 8 mM) at a test twitch changed this fractional SR Ca release to 10 +/- 2 and 59 +/- 6%, with the same SR Ca load (and peak ICa changed in a parallel manner in separate voltage-clamp experiments). Three different levels of SR Ca load were studied (Low, Normal, and High; by action potential stimulation at different frequencies from 0.05 to 0.8 Hz) using the same standard test trigger Ca (2 mM). Surprisingly, the High-load condition only increased SR Ca content by approximately 4% but appeared to be very close to the limiting SR Ca capacity.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0002-9513
pubmed:author
pubmed:issnType
Print
pubmed:volume
268
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
C1313-9
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Fractional SR Ca release is regulated by trigger Ca and SR Ca content in cardiac myocytes.
pubmed:affiliation
Department of Physiology, Loyola University School of Medicine, Maywood, Illinois 60153, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.