Linked Life Data

6698160

Source:http://linkedlifedata.com/resource/pubmed/id/6698160

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1984-4-6
pubmed:abstractText
Potassium and caffeine contractures of isolated small bundles (100 to 200 micron diameter) of muscle fibers isolated from the diaphragm of normal and dystrophic (C57BL/6J dy2J/dy2J) mice were compared. In diaphragms of pathologic mice (3 to 5 months old) the resting potential, the characteristics of the twitch, and some histological examinations were typical of dystrophic muscles. The slopes of the relationships between the steady membrane potential and log [K]0 were similar for the two types of cells. In 110 mM and 146 mM K there were no significant differences in the time course of the contractures and reduction in [Ca]0 decreased the time to peak and the time constant of relaxation to the same extent; the relative efficiency of [Mg]0 compared with [Ca]0 was equivalent. Repriming of K contractures at different external calcium concentrations indicated that the normal diaphragm did not have any special advantage. The exposure of isolated strips to a solution containing caffeine resulted in a similar increase of the strength of the regularly evoked twitch responses. However, the contractures elicited by 1.25 to 20 mM caffeine showed a subsensitivity of the dystrophic diaphragm (KmDys = 9.3 KmN) and the rate of relaxation was significantly slower than in normal muscle (in 20 mM caffeine, 50% decay time for normal muscle was 25.2 +/- 7.6 s and for dystrophic muscle 54.8 +/- 11.2 s. These results suggest an absence of major alterations in the mechanism of excitation-contraction coupling associated with dystrophy, except for a change in the specific element of the sarcoplasmic reticulum where caffeine acts.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0014-4886
pubmed:author
pubmed:issnType
Print
pubmed:volume
83
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
589-603
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1984
pubmed:articleTitle
A comparative study of contractile responses in diaphragm muscles of normal and dystrophic (C57BL/6J dy2J/dy2J) mice.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't