Document Detail


Development of cardiac sensitivity to oxygen deficiency: comparative and ontogenetic aspects.
MedLine Citation:
PMID:  10390514     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Hypoxic states of the cardiovascular system are undoubtedly associated with the most frequent diseases of modern times. They originate as a result of disproportion between the amount of oxygen supplied to the cardiac cell and the amount actually required by the cell. The degree of hypoxic injury depends not only on the intensity and duration of the hypoxic stimulus, but also on the level of cardiac tolerance to oxygen deprivation. This variable changes significantly during phylogenetic and ontogenetic development. The heart of an adult poikilotherm is significantly more resistant as compared with that of the homeotherms. Similarly, the immature homeothermic heart is more resistant than the adult, possibly as a consequence of its greater capability for anaerobic glycolysis. Tolerance of the adult myocardium to oxygen deprivation may be increased by pharmacological intervention, adaptation to chronic hypoxia, or preconditioning. Because the immature heart is significantly more dependent on transsarcolemmal calcium entry to support contraction, the pharmacological protection achieved with drugs that interfere with calcium handling is markedly altered. Developing hearts demonstrated a greater sensitivity to calcium channel antagonists; a dose that induces only a small negative inotropic effect in adult rats stops the neonatal heart completely. Adaptation to chronic hypoxia results in similarly enhanced cardiac resistance in animals exposed to hypoxia either immediately after birth or in adulthood. Moreover, decreasing tolerance to ischemia during early postnatal life is counteracted by the development of endogenous protection; preconditioning failed to improve ischemic tolerance just after birth, but it developed during the early postnatal period. Basic knowledge of the possible improvements of immature heart tolerance to oxygen deprivation may contribute to the design of therapeutic strategies for both pediatric cardiology and cardiac surgery.
Authors:
B Ostadal; I Ostadalova; N S Dhalla
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't; Review    
Journal Detail:
Title:  Physiological reviews     Volume:  79     ISSN:  0031-9333     ISO Abbreviation:  Physiol. Rev.     Publication Date:  1999 Jul 
Date Detail:
Created Date:  1999-07-23     Completed Date:  1999-07-23     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0231714     Medline TA:  Physiol Rev     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  635-59     Citation Subset:  IM    
Affiliation:
Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
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MeSH Terms
Descriptor/Qualifier:
Aging / physiology*
Animals
Anoxia / physiopathology*
Cardiomyopathies / physiopathology*
Disease Susceptibility
Humans
Ischemic Preconditioning
Myocardial Ischemia / physiopathology

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


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