Document Detail

Towards a molecular understanding of contractility.
MedLine Citation:
PMID:  2102805     Owner:  NLM     Status:  MEDLINE    
The contractile performance of the heart depends on the molecular force generators, the myosin crossbridges between thick and thin filaments. These are oscillating between two states, strong and weak, or force-generating and non-force-generating. Calcium activation of the contractile machinery increases the probability of forming force-generating crossbridges, whereas the speed of contraction depends on the probability of returning force-generating crossbridges into weak ones. It is inversely related to the energetic cost of contraction. The probabilities or rate constants describing the transitional states of the force generators (and denoted as g and f) describe not only the kinetic properties of the contractile system but also its responsiveness to the calcium activator. The development of force depends not only on the free calcium ion concentration in the myoplasm, but also on calcium responsiveness which is dependent both on crossbridge kinetics and the calcium affinity of the regulatory protein, troponin. In future, it will be important to find out how all these molecular properties of the force-generators are affected in diseased states as well by pharmacological interventions, such as the application of novel cardiotonic drugs.
J C Rüegg
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Review    
Journal Detail:
Title:  Cardioscience     Volume:  1     ISSN:  1015-5007     ISO Abbreviation:  Cardioscience     Publication Date:  1990 Sep 
Date Detail:
Created Date:  1991-10-03     Completed Date:  1991-10-03     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  9014943     Medline TA:  Cardioscience     Country:  ITALY    
Other Details:
Languages:  eng     Pagination:  163-8     Citation Subset:  IM    
Department of Physiology II University of Heidelberg.
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MeSH Terms
Calcium / physiology*
Coronary Disease / physiopathology
Myocardial Contraction / physiology*
Myosins / physiology*
Sarcomeres / ultrastructure
Troponin / physiology
Reg. No./Substance:
0/Troponin; 7440-70-2/Calcium; EC

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