Tetragonal deformation of the hexagonal myofilament matrix in single skinned skeletal muscle fibres owing to change in sarcomere length

1992 ◽  
Vol 13 (5) ◽  
pp. 573-580 ◽  
Author(s):  
P. Schiereck ◽  
E. L. de Beer ◽  
R. L. F. Grundeman ◽  
T. Manussen ◽  
N. Kylstra ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Sarcomere Length ◽  
Muscle Fibres ◽  
Skeletal Muscle Fibres

scholarly journals Sarcomere-length dependence of myosin filament structure in skeletal muscle fibres of the frog

2014 ◽  
Vol 592 (5) ◽  
pp. 1119-1137 ◽  
Author(s):  
Massimo Reconditi ◽  
Elisabetta Brunello ◽  
Luca Fusi ◽  
Marco Linari ◽  
Manuel Fernandez Martinez ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Sarcomere Length ◽  
Myosin Filament ◽  
Muscle Fibres ◽  
Length Dependence ◽  
Filament Structure ◽  
Skeletal Muscle Fibres

scholarly journals Modulation of passive force in single skeletal muscle fibres

2005 ◽  
Vol 1 (3) ◽  
pp. 342-345 ◽  
Author(s):  
Dilson E Rassier ◽  
Eun-Jeong Lee ◽  
Walter Herzog
Keyword(s):  
Skeletal Muscle ◽  
Sarcomere Length ◽  
Fibre Length ◽  
Muscle Fibres ◽  
Isometric Contractions ◽  
Passive Force ◽  
Length Relationship ◽  
Lumbrical Muscle ◽  
Single Fibres ◽  
Skeletal Muscle Fibres

In this study, we investigated the effects of activation and stretch on the passive force–sarcomere length relationship in skeletal muscle. Single fibres from the lumbrical muscle of frogs were placed at varying sarcomere lengths on the descending limb of the force–sarcomere length relationship, and tetanic contractions, active stretches and passive stretches (amplitudes of ca 10% of fibre length at a speed of 40% fibre length/s) were performed. The passive forces following stretch of an activated fibre were higher than the forces measured after isometric contractions or after stretches of a passive fibre at the corresponding sarcomere length. This effect was more pronounced at increased sarcomere lengths, and the passive force–sarcomere length relationship following active stretch was shifted upwards on the force axis compared with the corresponding relationship obtained following isometric contractions or passive stretches. These results provide strong evidence for an increase in passive force that is mediated by a length-dependent combination of stretch and activation, while activation or stretch alone does not produce this effect. Based on these results and recently published findings of the effects of Ca 2+ on titin stiffness, we propose that the observed increase in passive force is caused by the molecular spring titin.

Sarcomere length non-uniformity in relation to tetanic responses of stretched skeletal muscle fibres

1978 ◽  
Vol 200 (1138) ◽  
pp. 109-116 ◽  
Keyword(s):  
Skeletal Muscle ◽  
Thin Filament ◽  
Sarcomere Length ◽  
Muscle Fibres ◽  
Plateau Region ◽  
Constant Length ◽  
Tension Response ◽  
Force Velocity ◽  
Skeletal Muscle Fibres ◽  
Tetanic Tension

At sarcomere lengths above the plateau region of the length-tension diagram, it has been found that isometric tetanic tension is proportional to the amount of thick and thin filament overlap. This finding has been questioned recently and is reinvestigated here. Central segments of single frog skeletal muscle fibres were held at constant length during contractions at various sarcomere lengths above those associated with the plateau region. Tension records showed little or no creep, and the tetanic tensions measured at 0 and 20°C were inversely proportional to sarcomere length. These results extend and substantiate earlier findings. In contrast, when a stretched fibre had only its ends fixed during a tetanus, a different tension response was observed. The tension rise was initially very rapid but soon slowed to a gradual upward creep as stimulation was continued. This was followed by a tension decline. These tension phases were correlated with large decreases in sarcomere length at the fibre ends, while sarcomeres in the middle were extended a small amount. This tetanic tension response can be explained using the sarcomere length-tension relation and the force-velocity properties of muscle. These results strongly support the sliding filament, cross-bridge theory of muscle contraction.

Sign in / Sign up

Export Citation Format

Share Document