Document Detail

Defects in myoglobin oxygenation in K(ATP)-deficient mouse hearts under normal and stress conditions characterized by near infrared spectroscopy and imaging.
MedLine Citation:
PMID:  20202704     Owner:  NLM     Status:  In-Data-Review    
BACKGROUND: Disruption of ATP-sensitive potassium (K(ATP)) channel activity results in the development of dilated cardiomyopathy in response to different forms of stress, likely due to the underlying metabolic defects. To further understand the role of Kir6.2-containing channels in the development of cardiac disease, we analysed the left ventricular (LV) wall oxygenation and the physiologic responses induced by acute stress in non-dilated Kir6.2(-/-) hearts.
METHODS: Control (C57BL6) and Kir6.2(-/-) mouse hearts were perfused in constant flow Langendorff mode with Krebs-Henseleit buffer. Myocardial oxygenation was evaluated using a newly developed technique, near infrared spectroscopic imaging (NIRSI) of the myoglobin (Mb) oxygen saturation parameter (OSP, ratio of oxy- to total Mb).
RESULTS: 2,4-dinitrophenol (DNP, 50-µM) and isoproterenol (0.1-µM) failed to produce a transient vasodilatory response and caused a significant diastolic pressure increase in Kir6.2(-/-) hearts. DNP strongly suppressed contractile function in both groups and induced severe mean OSP decreases in Kir6.2(-/-) hearts. Isoproterenol-induced decreases in OSP were similar despite the lack of contractile function stimulation in the Kir6.2(-/-) group. The index of OSP spatial heterogeneity (relative dispersion, RD) was lower by 15% in the Kir6.2(-/-) group at the baseline conditions. Recovery after stress caused reduction of RD values by 20% (DNP) and 8% (isoproterenol) in controls; however, these values did not change in the Kir6.2(-/-) group.
CONCLUSIONS: 1) NIRSI can be used to analyse 2-D dynamics of LV oxygenation in rodent models of cardiomyopathy; 2) Kir6.2-containing K(ATP) channels play an important role in maintaining myocardial oxygenation balance under acute stress conditions and in post-stress recovery.
Olga Jilkina; Miriam Glogowski; Bozena Kuzio; Peter A Zhilkin; Eugene Gussakovsky; Valery V Kupriyanov
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Publication Detail:
Type:  Journal Article     Date:  2010-03-03
Journal Detail:
Title:  International journal of cardiology     Volume:  149     ISSN:  1874-1754     ISO Abbreviation:  Int. J. Cardiol.     Publication Date:  2011 Jun 
Date Detail:
Created Date:  2011-06-07     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8200291     Medline TA:  Int J Cardiol     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  315-22     Citation Subset:  IM    
Copyright Information:
Crown Copyright © 2010. Published by Elsevier Ireland Ltd. All rights reserved.
Institute for Biodiagnostics, National Research Council of Canada, Winnipeg, MB, Canada; Dept. of Oral Biology, University of Manitoba, Winnipeg, MB, Canada.
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