Linked Life Data

6634380

Source:http://linkedlifedata.com/resource/pubmed/id/6634380

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1983-12-17
pubmed:abstractText
Skinned fibres prepared by mechanical and/or chemical means from cardiac and skeletal muscles of the rat were activated in solutions strongly buffered for Ca2+ (with 50 mM EGTA) in the absence or presence of caffeine 5-40 mM. In all preparations caffeine was found to reversibly shift the relation between steady-state force and free [Ca2+] toward lower free [Ca2+] in a dose dependent manner. This increase in apparent Ca2+ sensitivity was not antagonized by procaine and was the same, within each muscle type, irrespective of the manner in which the skinned fibre was prepared, and consequently the degree to which it retained cellular membranes. The effect was more pronounced in cardiac and slow-twitch than in fast-twitch, myofibrillar preparations. At equivalent concentrations theophylline mimicked this effect of caffeine in all preparations, however, addition of exogenous cyclic AMP neither mimicked nor modified, in any way, the effect. Maximum Ca2+ -activated force production was not affected by caffeine below 20 mM but was depressed by concentrations of 20 mM and above. The increase in apparent Ca2+ sensitivity produced by caffeine can not be the result of a mobilization of some cellular store of Ca2+ but must arise from a direct effect of caffeine on the myofilaments which leads to a change in the apparent affinity constant of the force controlling sites for Ca2+.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0031-6768
pubmed:author
pubmed:issnType
Print
pubmed:volume
398
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
210-6
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1983
pubmed:articleTitle
Effects of caffeine on Ca-activated force production in skinned cardiac and skeletal muscle fibres of the rat.
pubmed:publicationType
Journal Article, In Vitro, Research Support, Non-U.S. Gov't