Introduction: A change in the fixed electrical charge between the rigor and the relaxed condition has been observed previously in the A-band of skeletal muscle. The aim of this study was to observe possible charge changes in the A-band during contraction and relate these to the contractile processes.
Material and Methods: Donnan potentials were measured in the relaxed state and during Ca-stimulated contractions in skinned rat and barnacle muscle fibres. From the potentials, the fixed electric charges in the A- and the I-bands were calculated
Results: A rise in negative charge was seen when moving from the relaxed to the contracted state. The A-band charge was more negative during contraction than the charge observed previously in rigor. The I-band charge follows the A-band charge during contraction. Conclusion: The difference in A-band charge in rigor and contracted state may be due to a charge change in both the rod and the head part of the myosin molecule during contraction, but only of the rod part in rigor. This is probably due to the effect of the increasing Pyrophosphate on the I-filament charge, as ATP decreases during contraction.
REFERENCES(33)
1.
Bartels EM, Elliott GF: Donnan potentials from the A- and I-bands of skeletal muscle, relaxed and in rigor. J Physiol (Lond) 1981, 317, 85- 87.
Bartels EM, Elliott GF: Donnan potentials from the A- and I-bands of glycerinated and chemically skinned muscles, relaxed and in rigor. Biophys J 1985, 48, 61-76.
Pemrick SM, Edwards C: Differences in the charge distribution of glycerol-extracted muscle fibers in rigor, relaxation, and contraction. J Gen Physiol 1974, 64(5), 551-567.
Öjteg G, Lundahl P, Wolgast M: The net electric charge of proteins. A comparison of determinations by Donnan potential measurements and by gel electrophoresis. Biochim Biophys Acta 1989, 991, 317-323.
Bartels EM, Cooke PH, Elliott GF, Hughes RA: A structural study of gels, in the form of threads, of myosin and myosin rod. Biophys J 1993, 51, 947-957.
Ashley CC, Moisescu DG: Effect of changing the composition of the bathing solutions upon the isometric tension-pCa relationship in bundles of crustacean myofibrils. J Phsiol 1977, 270, 627-652.
Beirao PS, Lakshminarayanaiah N: Calcium carrying system in the giant muscle fibre of the barnacle species, Balanus nubilis. J Physiol 1979, 293, 319-327.
Fryer MW, Stephenson DG: Total and sarcoplasmic reticulum calcium contents of skinned fibres from rat skeletal muscle. J Physiol (Lond.) 1996, 493, 357-370.
Lea TJ, Ashley CC: Ca-induced Ca release from the sarcoplasmic reticulum of isolated myofibrillar bundles of barnacle muscle fibres. Pflügers Arch 1989, 413, 401-406.
Bartels EM, Elliott GF: Donnan potentials in glycerinated rabbit skeletal muscle: the effects of nucleotides and of pyrophosphate. J Physiol (Lond.) 1983, 343, 32-33P.
Brenner B, Yu LC, Greene LE, Eisenberg E, Schoenberg M: Calciumsensitive crossbridge dissociation in the presence of magnesium pyrophosphate in skinned rabbit psoas fibers. Biophys J 1986, 50, 1101- 1108.
We process personal data collected when visiting the website. The function of obtaining information about users and their behavior is carried out by voluntarily entered information in forms and saving cookies in end devices. Data, including cookies, are used to provide services, improve the user experience and to analyze the traffic in accordance with the Privacy policy. Data are also collected and processed by Google Analytics tool (more).
You can change cookies settings in your browser. Restricted use of cookies in the browser configuration may affect some functionalities of the website.