Document Detail

MCI-154, a Ca2+ sensitizer, decreases the oxygen cost of contractility in isolated canine hearts.
MedLine Citation:
PMID:  9362231     Owner:  NLM     Status:  MEDLINE    
An increase in the responsiveness of the contractile machinery to Ca2+ could theoretically enhance the mechanoenergetics of the heart. To clarify this unresolved issue, we studied the effects of MCI-154, a Ca2+ sensitizer, on the mechanoenergetics in terms of the left ventricular contractility index [slope of end-systolic pressure-volume relationship (Emax)] and the relationship between myocardial oxygen consumption (VO2) and left ventricular pressure-volume area in excised cross-circulated canine hearts. MCI-154 increased Emax by 42 +/- 31% (SD), although the slope of the VO2-PVA relationship (an indicator of contractile efficiency) was unchanged by MCI-154. Despite equal increases in Emax, the relative increase in unloaded VO2 (delta VO2/delta Emax) during infusion of MCI-154 was, however, significantly less than that during CaCl2 infusion (0.0016 +/- 0.0018 vs. 0.0059 +/- 0.0054; P < 0.05). By contrast, delta VO2/delta Emax for milrinone was the same as that for CaCl2 (0.0043 +/- 0.0041 vs. 0.0039 +/- 0.0045; P > 0.05). Basal metabolism in KCl-arrested hearts was unchanged by MCI-154, indicating that MCI-154 consumes less energy than CaCl2 for excitation-contraction coupling. These findings suggest that MCI-154 acts energetically as a Ca2+ sensitizer in beating canine whole hearts.
K Onishi; K Sekioka; R Ishisu; Y Abe; H Tanaka; M Nakamura; Y Ueda; T Nakano
Publication Detail:
Type:  In Vitro; Journal Article    
Journal Detail:
Title:  The American journal of physiology     Volume:  273     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1997 Oct 
Date Detail:
Created Date:  1997-12-10     Completed Date:  1997-12-10     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  H1688-95     Citation Subset:  IM    
First Department of Internal Medicine, Mie University School of Medicine, Tsu, Japan.
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MeSH Terms
Blood Pressure / drug effects
Blood Volume / drug effects
Calcium / metabolism*
Energy Metabolism / drug effects
Heart Arrest, Induced
Myocardial Contraction / drug effects*
Myocardium / metabolism*
Oxygen Consumption / drug effects*
Potassium Chloride / pharmacology
Pyridazines / pharmacology*
Ventricular Function, Left / drug effects
Reg. No./Substance:
0/Pyridazines; 7440-70-2/Calcium; 7447-40-7/Potassium Chloride; 98326-33-1/MCI 154

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

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