Document Detail


Effects of linoleic acid metabolites on electrical activity in adult rat ventricular myocytes.
MedLine Citation:
PMID:  10366778     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Leukotoxin (Lx), an epoxide derivative of linoleic acid, has been suggested to be a toxic mediator of multiple organ failure in burn patients and of acute respiratory distress syndrome. Lx production was recently shown during myocardial ischemia/reperfusion. However, a recent study suggested that to be toxic Lx must be metabolized to Lx-diol. In the present study, isolated adult rat ventricular myocytes were studied with the whole-cell patch-clamp technique to determine the effects of these compounds on cardiac electrical activity. Measurements of action potentials showed that neither linoleic acid nor Lx (100 microM) caused any significant changes in action potential properties. However, Lx-diol in the range of 10-100 microM produced a dose dependent increase in duration and a decrease in overshoot of the action potential. Subsequent voltage clamp experiments isolating Na current (INa) and transient outward K current (Ito) revealed that Lx-diol inhibited INa and Ito by about 80% at 100 microM, while linoleic acid and Lx had no effect on these currents at the same concentration. While Lx-diol produced the same inhibition of INa and Ito at 100 microM, its effects were more potent on Ito with significant inhibition at 10 microM. Lx-diol also hastened the activation kinetics of Ito but not INa. The action of Lx-diol was rapid (reaching steady state in 3-5 min) and was reversible in 5-10 min following washout. Thus, Lx-diol could favor arrhythmias or cardiac arrest in intact heart and may be responsible for the cardiac problems seen in systemic inflammatory response syndrome. These results further support the suggestion that Lx is not toxic in the heart but rather must be metabolized to Lx-diol to produce toxic effects on cardiac muscle.
Authors:
J R Stimers; M Dobretsov; S L Hastings; A R Jude; D F Grant
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Biochimica et biophysica acta     Volume:  1438     ISSN:  0006-3002     ISO Abbreviation:  Biochim. Biophys. Acta     Publication Date:  1999 Jun 
Date Detail:
Created Date:  1999-07-19     Completed Date:  1999-07-19     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0217513     Medline TA:  Biochim Biophys Acta     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  359-68     Citation Subset:  IM    
Affiliation:
Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, 4301 W. Markham St., Slot 611, Little Rock, AR 72205, USA. stimersjosephr@exchange.uams.edu
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MeSH Terms
Descriptor/Qualifier:
Action Potentials / drug effects
Animals
Arrhythmias, Cardiac / etiology
Cells, Cultured
Dose-Response Relationship, Drug
Exotoxins / chemistry,  metabolism
Heart Ventricles / drug effects
Linoleic Acid / metabolism*,  pharmacology
Mass Spectrometry
Myocardium / metabolism*
Patch-Clamp Techniques
Potassium / chemistry
Rats
Sodium / chemistry
Stearic Acids / metabolism,  pharmacology
Grant Support
ID/Acronym/Agency:
GM56708/GM/NIGMS NIH HHS; HL44660/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/9,10-dihydroxy-12-octadecenoic acid; 0/Exotoxins; 0/Stearic Acids; 0/leukotoxin; 2197-37-7/Linoleic Acid; 7440-09-7/Potassium; 7440-23-5/Sodium

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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