Document Detail

Stunning does not change the relation between calcium and force in skinned rat trabeculae.
MedLine Citation:
PMID:  8377214     Owner:  NLM     Status:  MEDLINE    
To test the hypothesis that stunning is due to a decreased sensitivity of the myofibrils for calcium, we compared the isometric force-Ca2+ relation in skinned trabeculae from stunned and control hearts. Hearts were made ischemic for 40 min followed by 30 min reperfusion. In one group (Group 1) changes in left ventricular systolic and diastolic pressure were monitored. From another group (Group 2), trabeculae were isolated to determine the relation between force and Ca2+ concentration. Trabeculae isolated from hearts (Group 3) perfused aerobically for 90 min served as controls. Left ventricular developed pressure and end diastolic pressure were 5.9 +/- 0.7 kPa and 5.8 +/- 0.7 kPa, respectively in stunned hearts as compared to 9.9 +/- 1.2 kPa and 1.2 +/- 0.1 kPa prior to ischemia. The nucleotide content decreased from 24.9 +/- 3.4 mumol.g-1(dw) in control hearts to 9.3 +/- 0.8 mumol.g-1(dw) after ischemia and reperfusion while the creatine kinase levels were about the same. Force-Ca2+ relations obtained from trabeculae from control and stunned hearts were fitted to the Hill equation. Maximal isometric force, the midpoint and the steepness of the curves estimated for the two groups were not significantly different. We conclude that the maximum isometric force and the sensitivity of the contractile apparatus of skinned myocardium of stunned hearts do not differ from that of control hearts. This suggests that structural changes of the contractile proteins leading to a decreased sensitivity of the myofibrils to calcium are not involved in the mechanism responsible for stunning.
D L Dietrich; G R van Leeuwen; G J Stienen; G Elzinga
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Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  Journal of molecular and cellular cardiology     Volume:  25     ISSN:  0022-2828     ISO Abbreviation:  J. Mol. Cell. Cardiol.     Publication Date:  1993 May 
Date Detail:
Created Date:  1993-10-21     Completed Date:  1993-10-21     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0262322     Medline TA:  J Mol Cell Cardiol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  541-9     Citation Subset:  IM    
Laboratory for Physiology, Free University, Amsterdam, The Netherlands.
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MeSH Terms
Calcium / physiology*
Creatine Kinase / metabolism
Histological Techniques
Isometric Contraction / physiology*
Myocardial Ischemia / complications,  physiopathology*
Nucleotides / metabolism
Rats, Wistar
Reg. No./Substance:
0/Nucleotides; 7440-70-2/Calcium; EC Kinase

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