Document Detail


Nitric oxide depresses connexin 43 after myocardial infarction in mice.
MedLine Citation:
PMID:  18394025     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
AIMS: Heart failure (HF) is a major cause of death and morbidity. Connexin 43 (Cx43) content is reduced in the failing myocardium, but regulating factors have not been identified. In HF, inducible nitric oxide synthase (iNOS)-induced high levels of nitric oxide (NO) cause apoptosis and cardiac dysfunction. However, a direct iNOS-Cx43 link has not been demonstrated. We investigated this relationship in mice after myocardial infarction.
METHODS: Effects of myocardial infarction were evaluated 2 weeks after coronary artery ligation in wild-type C57BL/6 (WT) and iNOS(-/-) knockout mice. Myocardial Cx43 and Cx45 content were assessed by immunofluorescence confocal imaging and western blotting. Cardiac function was evaluated in anaesthetized mice using a micro pressure-tipped catheter inserted into the left ventricle.
RESULTS: Despite similar infarct size, deficiency in iNOS resulted in significantly lower plasma nitrate/nitrite levels, better haemodynamic performance and lower mortality 2 weeks after coronary ligation. Myocardial Cx43, but not Cx45, content was lower in WT mice following ligation. The reduction in Cx43 was less in iNOS(-/-) compared with WT mice. To assess the direct effect of NO on Cx43 expression, cultured neonatal mouse cardiomyocytes were employed. Incubation with the NO donor, S-nitroso-N-acetylpenicillamine, elicited a dose-dependent decrease in Cx43 content in cultured neonatal cardiomyocytes.
CONCLUSIONS: Increased NO production from iNOS depressed cardiac performance and contributed to the decreased myocardial Cx43 content 2 weeks after myocardial infarction.
Authors:
P E M Jackson; Q P Feng; D L Jones
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't     Date:  2008-04-03
Journal Detail:
Title:  Acta physiologica (Oxford, England)     Volume:  194     ISSN:  1748-1716     ISO Abbreviation:  Acta Physiol (Oxf)     Publication Date:  2008 Sep 
Date Detail:
Created Date:  2008-08-12     Completed Date:  2008-10-03     Revised Date:  2011-10-27    
Medline Journal Info:
Nlm Unique ID:  101262545     Medline TA:  Acta Physiol (Oxf)     Country:  England    
Other Details:
Languages:  eng     Pagination:  23-33     Citation Subset:  IM    
Affiliation:
Department of Physiology, University of Western Ontario, London, ON, Canada.
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MeSH Terms
Descriptor/Qualifier:
Animals
Animals, Newborn
Blotting, Western / methods
Cells, Cultured
Connexin 43 / analysis,  metabolism*
Depression, Chemical
Mice
Mice, Inbred C57BL
Mice, Knockout
Microscopy, Confocal
Models, Animal
Myocardial Infarction / metabolism*
Myocardium / metabolism*
Myocytes, Cardiac / drug effects,  metabolism
Nitric Oxide / metabolism*
Nitric Oxide Synthase Type II / antagonists & inhibitors*,  genetics,  metabolism
Random Allocation
S-Nitroso-N-Acetylpenicillamine / pharmacology
Chemical
Reg. No./Substance:
0/Connexin 43; 10102-43-9/Nitric Oxide; 79032-48-7/S-Nitroso-N-Acetylpenicillamine; EC 1.14.13.39/NOS2 protein, human; EC 1.14.13.39/Nitric Oxide Synthase Type II
Comments/Corrections
Comment In:
Acta Physiol (Oxf). 2008 Sep;194(1):1   [PMID:  18694420 ]

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