Linked Life Data

8768729

Source:http://linkedlifedata.com/resource/pubmed/id/8768729

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1996-9-18
pubmed:abstractText
In electrically driven guinea pig left atria, plumbagin (5-hydroxy-2-methyl-1,4-naphthoquinone; 0.5-10 microM) produced a marked positive inotropic effect that was about 65% that caused by isoprenaline in the same experimental conditions. The effect was mainly not dependent on catecholamine release from adrenergic stores. An EC50 of 3 microM was calculated from the concentration-response curves. The increase in force of contraction was followed by a nonreversible contracture. Plumbagin was reduced by cardiac mitochondrial and soluble reductases with consequent generation of large amounts of superoxide anion. The assay of reduced glutathione/oxidized glutathione content in atria, treated with 10 microM plumbagin and frozen at the appearance of increase in diastolic tension, showed a significant decrease in reduced glutathione (-52% with respect to control atria) and a 5-fold increase in oxidized glutathione levels. Moreover, in the same experimental conditions a significant decrease in adenosine triphosphate (-55% with respect to the controls) and in adenylate energy charge (from 0.92-0.64) was observed. Of the enzymes and transport systems involved in the control of the cardiac contractility, the sarcoplasmic reticulum Ca2+ pump seemed to be a specific target for plumbagin. After 30 min of incubation with cardiac sarcoplasmic reticulum membrane vesicles, plumbagin inhibited Ca2+ uptake by the pump in a concentration-dependent manner (IC50 = 3 microM). On the basis of these results, the increase in diastolic tension caused by plumbagin appears to be related to intracellular Ca2+ accumulation, due both to the low availability of adenosine triphosphate for ionic pumps and direct inhibition of Ca2+ reuptake in sarcoplasmic reticulum.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0022-3565
pubmed:author
pubmed:issnType
Print
pubmed:volume
278
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
763-70
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
Mechanisms of plumbagin action on guinea pig isolated atria.
pubmed:affiliation
Department of Pharmacology, University of Padova, Italy.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't