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Influence of temperature upon contractile activation and isometric force production in mechanically skinned muscle fibers of the frog
The pCa required for 50% maximal force (pCa50) was inversely proportional to absolute temperature, and the shift was consistent with a Gibbs free energy change of binding (delta G) of about -7.8 kcal/mol. Expand
Changes of intracellular milieu with fatigue or hypoxia depress contraction of skinned rabbit skeletal and cardiac muscle.
Simple summation of all significant changes expected from each constituent altered by fatigue/hypoxia adequately predicted the observed changes in Fmax and Ca2+ sensitivity in both cardiac and skeletal muscle fibres with but one exception (the change in Ca2- sensitivity of skeletal muscle at pH 7 was slightly overestimated). Expand
On the composition of the cytosol of relaxed skeletal muscle of the frog.
This review summarizes a variety of estimates for the concentrations of the principal cytosolic constituents in frog skeletal muscle and uses electroneutrality and osmotic considerations to ensure that all major constituents have been considered. Expand
Role of cardiac neural crest cells in cardiovascular development.
Evidence indicates that poor viability is from impaired cardiac excitation-contraction coupling and contractile function at the myocyte level, and the continued study of experimental and genetically defined models with neural crest-associated heart defects will prove useful in identifying the common pathways by which the neural crest contributes to normal heart development. Expand
Influence of osmotic compression on calcium activation and tension in skinned muscle fibers of the rabbit
Changes in Ca2+-sensitivity might be explained by changes in cross-bridge angle or in the concomitant attachment-detachment rate constants which would be expected to influence the troponin-Ca2+ binding equilibrium, as has been proposed by others. Expand
Inhibitory influence of phosphate and arsenate on contraction of skinned skeletal and cardiac muscle.
It was found that both Pi and Asi were more effective in decreasing Fmax as the pH was lowered (i.e., as the concentration of the diprotonated forms increased), while soleus and cardiac fibers did not exhibit this behavior. Expand
Relationship between short-range stiffness and yielding in type-identified, chemically skinned muscle fibers from the cat triceps surae muscles.
The hypothesis that type I fibers are specialized in presenting a high short-range stiffness for effective postural control in advance of reflex mechanisms is supported and that this property results from intrinsic properties of the fiber and is not due to differences in the dimensions of type I and II fibers. Expand
Calcium-Activated Tension of Skinned Muscle Fibers of the Frog
  • R. Godt
  • Chemistry, Medicine
  • The Journal of general physiology
  • 1 June 1974
Tension data from skinned fibers substantially supports the hypothesis that a mechanism whereby, at low ATP, "rigor complexes" are formed between myosin and thin filament actin and, in turn, alter the calcium affinity of one class of the two Ca++-binding sites on troponin is "turned on" for contraction at lower Ca++ levels. Expand
Swelling of skinned muscle fibers of the frog. Experimental observations.
Frog skeletal muscle fibers swell upon transfer to aqueous relaxing medium, consistent with the idea that swelling arises from the negatively charged nature of the myofilaments, from either mutual filamentary repulsion or a Donnan-osmotic mechanism. Expand
Stretch and radial compression studies on relaxed skinned muscle fibers of the frog.
Values of bulk moduli of fibers, calculated from the compression experiments, and preliminary measurements of Young's modulus from stretch experiments, are quantitatively consistent with the idea that skinned fibers behave as nonisotropic elastic bodies. Expand