Ouabain increases myofibrillar Ca2+ sensitivity but does not influence the Ca2+ release in human skinned fibres

2004 ◽  
Author(s):  
N HAMBARCHIAN
Keyword(s):  
Skinned Fibres

Studies on Water in Barnacle Muscle Fibres II. Role of ions and Organic Solutes in Swelling of Chemically-skinned Fibres

1981 ◽  
Vol 90 (1) ◽  
pp. 43-63
Author(s):  
M. E. CLARK ◽  
J. A. M. HINKE ◽  
M. E. TODD
Keyword(s):  
Water Content ◽  
Fibre Volume ◽  
Tween 20 ◽  
Muscle Fibres ◽  
Skinned Fibres ◽  
Organic Solutes ◽  
Net Charge ◽  
Trimethylamine Oxide ◽  
Organic Solute

Single muscle fibres from the giant barnacle, Balanus nubilis, were chemically skinned (2% Tween 20), then equilibrated for 40 h in salt solutions ranging in ionic strength from 0·025 to 0·6M at pH 7·0. The water content of the fibres and the net charge on the myofilaments increased with increasing salt concentration. Cation accumulation in the fibres was about equal to anion exclusion at all salt concentrations. When an organic solute (trimethylamine oxide, glycine, alanine, serine, proline, or glycerol) in the concentration range from 0·1 to 0·6 M was added to the salt solution, cation accumulation increased and water content decreased. Myofilament architecture was disrupted when the fibres were equilibrated in high salt (> 0·4 M) solutions and preserved when 0·5 M-triethylamine oxide was also added. The results are consistent with the view that organic solutes enhance the association between the fixed charge sites and their counterions. This hypothesis is examined quantitatively using the Oosawa relationship between the volume and the counterion association for cylindrical polyelectrolytes. The results illustrate that organic solutes can influence fibre volume in a way other than through osmo-regulation.

Some mechanical properties of skinned fibres of pregnant human myometrium

1994 ◽  
Vol 56 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Hidetaka Izumi ◽  
R.E. Garfield ◽  
Fujio Morishita ◽  
Koichi Shirakawa
Keyword(s):  
Mechanical Properties ◽  
Human Myometrium ◽  
Skinned Fibres

scholarly journals Power Output and Force-Velocity Relationship of Live Fibres from White Myotomal Muscle of the Dogfish, Scyliorhinus Canicula

1988 ◽  
Vol 140 (1) ◽  
pp. 187-197 ◽  
Author(s):  
N. A. CURTIN ◽  
R. C. WOLEDGE
Keyword(s):  
Power Output ◽  
Maximum Velocity ◽  
Muscle Fibres ◽  
Fish Length ◽  
Skinned Fibres ◽  
Step Method ◽  
Velocity Relationship ◽  
Velocity Of Shortening ◽  
Force Velocity ◽  
Myotomal Muscle

The relationship between force and velocity of shortening and between power and velocity were examined for myotomal muscle fibre bundles from the dogfish. The maximum velocity of shortening, mean value 4.8 ± 0.2 μms−1 half sarcomere−1 (±S.E.M., N = 13), was determined by the ‘slack step’ method (Edman, 1979) and was found to be independent of fish length. The force-velocity relationship was hyperbolic, except at the high-force end where the observations were below the hyperbola fitted to the rest of the data. The maximum power output was 91 ± 14 W kg−1 wet mass (±S.E.M., N = 7) at a velocity of shortening of 1.3 ± 0.13μms−1 halfsarcomere−1 (±S.E.M., N = 7). This power output is considerably higher than that previously reported for skinned fibres (Bone et al. 1986). Correspondingly the force-velocity relationship is less curved for intact fibres than for skinned fibres. The maximum swimming speed (normalized for fish length) predicted from the observed power output of the muscle fibres decreased with increasing fish size; it ranged from 12.9 to 7.8 fish lengths s−1 for fish 0155–0.645m in length.

scholarly journals Presence of enolase in the M-band of skeletal muscle and possible indirect interaction with the cytosolic muscle isoform of creatine kinase

1999 ◽  
Vol 338 (1) ◽  
pp. 115-121 ◽  
Author(s):  
Georges FOUCAULT ◽  
Monique VACHER ◽  
Tatyana MERKULOVA ◽  
Angelica KELLER ◽  
Martine ARRIO-DUPONT
Keyword(s):  
Skeletal Muscle ◽  
Creatine Kinase ◽  
Energy Metabolism ◽  
Direct Interaction ◽  
Cross Linking ◽  
Muscle Fibres ◽  
Skinned Fibres ◽  
Two Dimensional Gel Electrophoresis ◽  
The Cross ◽  
Skeletal Muscle Fibres

Glycerol-skinned skeletal muscle fibres retain the defined sarcomeric structure of the myofibrils. We show here that a small fraction of two enzymes important for energy metabolism, the cytosolic muscle isoform of creatine kinase (EC 2.7.3.2), MM-creatine kinase (MM-CK), and enolase (EC 4.2.1.11), remains bound to skinned fibres. CK is slowly exchangeable, whereas enolase is firmly bound. Two-dimensional gel electrophoresis followed by Western blot analyses demonstrates that both α (ubiquitous) and β (muscle-specific) subunits of enolase are present in these preparations. Enolase and CK were co-localized at the M-band of the sarcomeres, as observed by indirect immunofluorescence and confocal microscopy. Cross-linking experiments were performed on skinned fibres with three bifunctional succinimidyl esters of different lengths and yielded a protein complex of 150 kDa that reacted with antibodies directed against either M-CK or β-enolase. The cross-linking efficiency was greatest for the longest reagent and zero for the shortest one. The length of the cross-linker giving a covalent complex between the two enzymes does not support the notion of a direct interaction between M-CK and enolase. This is the first demonstration of the presence of an enzyme of energy metabolism other than CK at the M-band of myofibres.

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