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The increase in non-cross-bridge forces after stretch of activated striated muscle is related to titin isoforms
- Source :
- American Journal of Physiology-Cell Physiology. 310:C19-C26
- Publication Year :
- 2016
- Publisher :
- American Physiological Society, 2016.
-
Abstract
- Skeletal muscles present a non-cross-bridge increase in sarcomere stiffness and tension on Ca2+ activation, referred to as static stiffness and static tension, respectively. It has been hypothesized that this increase in tension is caused by Ca2+-dependent changes in the properties of titin molecules. To verify this hypothesis, we investigated the static tension in muscles containing different titin isoforms. Permeabilized myofibrils were isolated from the psoas, soleus, and heart ventricle from the rabbit, and tested in pCa 9.0 and pCa 4.5, before and after extraction of troponin C, thin filaments, and treatment with the actomyosin inhibitor blebbistatin. The myofibrils were tested with stretches of different amplitudes in sarcomere lengths varying between 1.93 and 3.37 μm for the psoas, 2.68 and 4.21 μm for the soleus, and 1.51 and 2.86 μm for the ventricle. Using gel electrophoresis, we confirmed that the three muscles tested have different titin isoforms. The static tension was present in psoas and soleus myofibrils, but not in ventricle myofibrils, and higher in psoas myofibrils than in soleus myofibrils. These results suggest that the increase in the static tension is directly associated with Ca2+-dependent change in titin properties and not associated with changes in titin-actin interactions.
- Subjects :
- 0301 basic medicine
Time Factors
animal structures
Physiology
macromolecular substances
In Vitro Techniques
Reply LTE
Sarcomere
Psoas Muscles
Troponin C
03 medical and health sciences
Myofibrils
Myosin
medicine
Animals
Protein Isoforms
Connectin
Muscle Strength
Actin
biology
Chemistry
Myocardium
Cell Biology
Anatomy
musculoskeletal system
030104 developmental biology
embryonic structures
biology.protein
Biophysics
Calcium
Titin
Rabbits
medicine.symptom
Myofibril
tissues
Muscle Contraction
Muscle contraction
Subjects
Details
- ISSN :
- 15221563 and 03636143
- Volume :
- 310
- Database :
- OpenAIRE
- Journal :
- American Journal of Physiology-Cell Physiology
- Accession number :
- edsair.doi.dedup.....4644f65cc9f89ca56617559450261723