Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Experiment Videos

The sarcomeric control of energy conversion.

Carmit Levy1, Henk E D J Ter Keurs, Yael Yaniv

  • 1Faculty of Biomedical Engineering, Technion, Israel Institute of Technology, Haifa 32000, Israel.

Annals of the New York Academy of Sciences
|August 12, 2005
PubMed
Summary

Cardiac muscle contraction relies on two feedbacks: cooperativity for calcium binding and mechanical feedback for shortening velocity. These mechanisms adapt energy use to loading conditions, explaining cardiac efficiency and force-length relationships.

Related Concept Videos

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Increased Ca<sup>2+</sup> Sequestration by the Sarco-/Endoplasmic Reticulum in Cardiac Purkinje Cells After Myocardial Infarction.

Cells·2026
Same author

Decoy antibodies block extracellular HSP70, prevent self-signaling, and inhibit melanoma cell survival.

Cell reports·2026
Same author

Sympatho-vagal balance and intrinsic sinoatrial node activity in larval zebrafish quantified by heart rate variability.

Scientific reports·2026
Same author

Multilevel metabolic adaptation to exercise training.

Communications medicine·2026
Same author

Nuclear import of malaria RNA rewires splicing in host immune cells.

Cell reports·2026
Same author

UV-induced immune modulation in the lung niche slows cancer progression.

Scientific reports·2026

Area of Science:

  • Cardiovascular Physiology
  • Muscle Mechanics
  • Biophysics

Background:

  • Cardiac mechanics and energetics are influenced by loading conditions, as suggested by the Frank-Starling Law and Fenn Effect.
  • Suga's work highlights constant contractile efficiency in cardiac muscle.
  • Sarcomere control involves complex feedback mechanisms.

Purpose of the Study:

  • To elucidate the two dominant feedback mechanisms controlling sarcomere contraction: cooperativity and mechanical feedback.
  • To explain how these feedbacks regulate cardiac energy consumption based on loading conditions.
  • To validate these mechanisms through experimental testing of cardiac trabeculae.

Main Methods:

  • Review of existing literature on cardiac mechanics and energetics.

Related Experiment Videos

  • Theoretical modeling of cooperativity and mechanical feedback in sarcomere contraction.
  • Experimental validation using force responses to sarcomere length oscillations in tetanized trabeculae.

    • Main Results:

    • Identified a cooperativity mechanism (positive feedback) linking cross-bridge number to calcium affinity.
    • Identified a mechanical feedback (negative feedback) relating shortening velocity to cross-bridge turnover.
    • Experimental data showed force-length hysteresis, confirming delayed force responses and validating the feedback mechanisms' role in work generation and XB recruitment.

    Conclusions:

    • The cooperativity mechanism regulates cross-bridge recruitment, explaining the cardiac force-length calcium relationship and the Frank-Starling Law.
    • The mechanical feedback explains the force-velocity relationship and intrinsic high contractile efficiency.
    • Cross-bridges act as sensors, modulating recruitment and energy consumption in response to changes in length and load.