Cross-bridge movement in rat cardiac muscle as a function of calcium concentration.
AUTOR(ES)
Matsubara, I
RESUMO
1. By applying the X-ray diffraction method to chemically skinned papillary muscles of the rat, the transfer of myosin heads from the thick to the thin filaments was studied as a function of Ca2+ concentration. 2. No significant transfer of the heads occurred when the Ca2+ concentration was below the threshold of contraction (pCa 6.2). 3. During the maximum isometric contraction at pCa 4.4, 80% of the myosin heads were transferred to the thin filament. 4. When the muscle was activated isometrically at low Ca2+ concentrations (pCa 6.2-5.8), where the average tension was less than 20% of the maximum, a disproportionately large number of myosin heads were transferred to the thin filament. 5. It was concluded that a significant fraction of the heads transferred at the low Ca2+ concentrations does not produce tension.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1189283Documentos Relacionados
- Cross-bridge scheme and force per cross-bridge state in skinned rabbit psoas muscle fibers.
- Mechanism of action of endothelin in rat cardiac muscle: cross-bridge kinetics and myosin light chain phosphorylation.
- Strain-dependent cross-bridge cycle for muscle.
- Cross-bridge movement in fast and slow skeletal muscles of the chick.
- CROSS-BRIDGE PROPERTIES DERIVED FROM MUSCLE ISOTONIC VELOCITY TRANSIENTS
