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Regional variation in myofilament length-dependent activation
Olivier Cazorla1, Alain Lacampagne
1INSERM U-1046, Physiopathologie Cardiovasculaire, Université Montpellier1, Université Montpellier2, CHU Arnaud de Villeneuve, 34295, Montpellier, France. Olivier.cazorla@inserm.fr
Pflugers Archiv : European Journal of Physiology
|February 22, 2011
Summary
The Frank-Starling law explains heart regulation, but its cellular mechanisms involve length-dependent activation. This review explores how heart muscle variations impact this process and overall heart function.
Area of Science:
- Cardiology
- Molecular Biology
- Physiology
Background:
- The Frank-Starling law describes the heart's ability to increase contraction force with greater filling.
- Cellular mechanisms involve length-dependent activation, where longer sarcomere length increases myofilament calcium sensitivity.
- The left ventricle exhibits structural and functional heterogeneity, leading to non-uniform contractile properties.
Purpose of the Study:
- To review the role of the contractile machinery in transmural contractile heterogeneity.
- To examine the adaptation of contractile properties to muscle strain.
- To discuss the importance and consequences of transmural heterogeneity in length-dependent activation.
Main Methods:
- Review of existing literature on cardiac contractile machinery.
- Analysis of myosin isoforms, titin-based passive tension, and sarcomeric regulatory proteins.
- Discussion of cellular and regional differences in the left ventricle.
Main Results:
- Regional differences in contractile properties are influenced by transmural variations in action potentials and calcium handling.
- Myosin isoforms, titin, and regulatory proteins contribute to regional cellular contractile properties.
- Transmural heterogeneity in length-dependent activation affects overall heart mechanics.
Conclusions:
- The contractile machinery plays a crucial role in the heart's heterogeneous mechanical behavior.
- Understanding transmural differences in length-dependent activation is vital for comprehending heart function.
- Molecular mechanisms of strain transduction to the contractile machinery require further investigation.
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