Linked Life Data

150953

Source:http://linkedlifedata.com/resource/pubmed/id/150953

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1978-11-18
pubmed:abstractText
We studied the effects of caffeine on calcium transport by subcellular organelles isolated from rabbit myocardium. Caffeine increased myofibrillar basic and calcium-activated ATPase activity at 20 mM but not at lower concentrations. Mitochondrial and sarcoplasmic reticulum (SR) calcium accumulation was measured both by dual wavelength spectrophotometry with the calcium-sensitive dye, murexide, and by Millipore filtration with 45Ca. In mitochondria, caffeine impaired phosphate-assisted calcium transport but did not alter the closely related parameters of oxygen uptake, P/O ratio (nmol adenosine diphosphate consumed/n ats oxygen consumed, state 3 respiration) or limited calcium loading. In SR, caffeine impaired calcium accumulation. New methods were used to characterize calcium accumulation in the absence of oxalate according to first order reaction kinetics. Caffeine increased the rate constant while decreasing the calcium accumulated. It also increased the associated calcium-activated ATPase activity at low (30 mM) but not high (240 micrometer) external calcium concentration. In the presence of oxalate, caffeine decreased the rate of calcium accumulation, more with low than high calcium concentration. Net efflux of 45Ca from preloaded SR also was increased by caffeine. The findings indicate that caffeine impairs active calcium accumulation by making SR vesicle membranes more permeable to calcium.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0009-7330
pubmed:author
pubmed:issnType
Print
pubmed:volume
43
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
520-6
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed:year
1978
pubmed:articleTitle
Action of caffeine on calcium transport by isolated fractions of myofibrils, mitochondria, and sarcoplasmic reticulum from rabbit heart.
pubmed:publicationType
Journal Article, In Vitro