Interpreting cardiac muscle force-length dynamics using a novel functional model
| Autor: | Bryan K. Slinker, R. D. Kirkpatrick, Murali Chandra, Kenneth B. Campbell, William C. Hunter |
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| Rok vydání: | 2004 |
| Předmět: |
Recruitment
Neurophysiological Sarcomeres Physiology Muscle Fibers Skeletal Tropomyosin In Vitro Techniques Models Biological Cross bridge Model validation Mice Physiology (medical) Distortion Myosin medicine Animals Physics Myosin Heavy Chains Myocardium Dynamics (mechanics) Cardiac muscle Ferrets Reproducibility of Results Heart Anatomy Muscle stiffness Myocardial Contraction Rats Actin Cytoskeleton Kinetics medicine.anatomical_structure Nonlinear Dynamics Force length Biophysics Linear Models Rabbits Cardiology and Cardiovascular Medicine Algorithms |
| Zdroj: | American journal of physiology. Heart and circulatory physiology. 286(4) |
| ISSN: | 0363-6135 |
| Popis: | To describe the dynamics of constantly activated cardiac muscle, we propose that length affects force via both recruitment and distortion of myosin cross bridges. This hypothesis was quantitatively tested for descriptive and explanative validity. Skinned cardiac muscle fibers from animals expressing primarily α-myosin heavy chain (MHC) (mouse, rat) or β-MHC (rabbit, ferret) were activated with solutions from pCa 6.1 to 4.3. Activated fibers were subjected to small-amplitude length perturbations [Δ L( t)] rich in frequency content between 0.1 and 40 Hz. In descriptive validation tests, the model was fit to the ensuing force response [ΔF( t)] in the time domain. In fits to 118 records, the model successfully accounted for most of the measured variation in ΔF( t) ( R2 range, 0.997–0.736; median, 0.981). When some residual variations in ΔF( t) were not accounted for by the model (as at low activation), there was very little coherence ( |
| Databáze: | OpenAIRE |
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