Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1987-8-28
pubmed:abstractText
Cellular Ca uptake and efflux in rabbit ventricular muscle was measured using double-barreled Ca microelectrodes in the extracellular space. When repetitive stimulation was stopped there was a slow loss of cellular Ca. Upon resumption of stimulation Ca was taken up by the cells. These Ca movements are thought to represent the loss of Ca from the sarcoplasmic reticulum and the cell during rest and the refilling of the sarcoplasmic reticulum during stimulation. Ryanodine (100 nM) greatly enhanced both the efflux of Ca during rest and the uptake of Ca induced by stimulation. These results are consistent with the conclusions drawn below, but they are dependent upon the interpretation that these extracellular Ca depletions are indicative of sarcoplasmic reticulum Ca movements. To examine further this process, contractures induced by rapid cooling to 0 degrees C were used as an independent assay of sarcoplasmic reticulum Ca content. These rapid cooling contractures were smaller after longer rest intervals (declining with a half time of 1.5 min). In the presence of ryanodine, the rapid cooling contracture immediately after a contraction was greater than that seen under control conditions. However, in the presence of ryanodine these rapid cooling contractures decline as a function of rest duration with a half time of about 1 s. These results suggest that in the presence of ryanodine the sarcoplasmic reticulum can still take up Ca, but that it also loses this Ca very rapidly at the onset of rest.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0008-4212
pubmed:author
pubmed:issnType
Print
pubmed:volume
65
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
610-8
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1987
pubmed:articleTitle
The mechanism of ryanodine action in rabbit ventricular muscle evaluated with Ca-selective microelectrodes and rapid cooling contractures.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't