Document Detail


Glucose is arrhythmogenic in the anoxic-reoxygenated embryonic chick heart.
MedLine Citation:
PMID:  8726226     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Unlike in adult heart, embryonic myocardium works at low PO2 and depends preferentially on glucose. Therefore, activity of the embryonic heart during anoxia and reoxygenation should be particularly affected by changes in glucose availability. Hearts excised from 4-d-old chick embryos were submitted in vitro to strictly controlled anoxia-reoxygenation transitions at glucose concentrations varying from 0 to 20 mmol/L. Spontaneous and regular heart contractions were detected optically as movements of the ventricle wall and instantaneous heart rate, amplitude of contraction, and velocities of contraction and relaxation were determined. Anoxia induced transient tachycardia and rapidly depressed contractile activity, whereas reoxygenation provoked a temporary and complete cardioplegia (oxygen paradox). In the presence of glucose, atrial rhythm became irregular during anoxia and chaotic-periodic during reoxygenation. The incidence of these arrhythmias depended on duration of anoxia, and no ventricular ectopic beats were observed. Removal of glucose or blockade of glycolysis suppressed arrhythmias. These results show similarities but also differences with respect to the adult heart. Indeed, glucose 1) delayed and anoxic contractile failure, shortened the reoxygenation-induced cardiac arrest, and improved the recovery of contractile activity; 2) attenuated stunning at 20 mmol/L but worsened it at 8 mmol/L; and 3) paradoxically, was arrhythmogenic during anoxia and reoxygenation, especially when present at the physiologic concentration of 8 mmol/L. The last named phenomenon seems to be characteristic of the young embryonic heart, and our findings underscore that fluctuations of glycolytic activity may play a role in the reactivity of the embryonic myocardium to anoxiareoxygenation transitions.
Authors:
L Tran; P Kucera; Y de Ribaupierre; A C Rochat; E Raddatz
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Pediatric research     Volume:  39     ISSN:  0031-3998     ISO Abbreviation:  Pediatr. Res.     Publication Date:  1996 May 
Date Detail:
Created Date:  1996-10-21     Completed Date:  1996-10-21     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0100714     Medline TA:  Pediatr Res     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  766-73     Citation Subset:  IM    
Affiliation:
Institute of Physiology, University of Lausanne, Switzerland.
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MeSH Terms
Descriptor/Qualifier:
Animals
Anoxia / complications,  metabolism
Arrhythmias, Cardiac / etiology*,  metabolism
Chick Embryo
Glucose / metabolism,  pharmacology*
Heart / drug effects*
Myocardial Reperfusion Injury / complications*,  metabolism
Myocardium / metabolism
Chemical
Reg. No./Substance:
50-99-7/Glucose

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


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