Implanting an Artificial Skeletal Muscle into the Human Body: Towards an Ionic-Strength based Prototype

Author(s):  
B. Tondu ◽  
N. Bardou ◽  
S. Mathé
1972 ◽  
Vol 59 (3) ◽  
pp. 347-359 ◽  
Author(s):  
P. C. Vaughan ◽  
J. N. Howell ◽  
R. S. Eisenberg

The capacitance of skeletal muscle fibers was measured by recording with one microelectrode the voltage produced by a rectangular pulse of current applied with another microelectrode. The ionic strength of the bathing solution was varied by isosmotic replacement of NaCl with sucrose, the [K] [Cl] product being held constant. The capacitance decreased with decreasing ionic strength, reaching a value of some 2 µF/cm2 in solutions of 30 mM ionic strength, and not decreasing further in solutions of 15 mM ionic strength. The capacitance of glycerol-treated fibers did not change with ionic strength and was also some 2 µF/cm2. It seems likely that lowering the ionic strength reduces the capacitance of the tubular system (defined as the charge stored in the tubular system), and that the 2 µF/cm2 which is insensitive to ionic strength is associated with the surface membrane. The tubular system is open to the external solution in low ionic strength solutions since peroxidase is able to diffuse into the lumen of the tubules. Twitches and action potentials were also recorded from fibers in low ionic strength solutions, even though the capacitance of the tubular system was very small in these solutions. This finding can be explained if there is an action potential—like mechanism in the tubular membrane.


2019 ◽  
Vol 127 (2) ◽  
pp. 645-653 ◽  
Author(s):  
Ivan J. Vechetti

Extracellular vesicles (EVs) were initially characterized as “garbage bags” with the purpose of removing unwanted material from cells. It is now becoming clear that EVs mediate intercellular communication between distant cells through a transfer of genetic material, a process important to the systemic adaptation in physiological and pathological conditions. Although speculative, it has been suggested that the majority of EVs that make it into the bloodstream would be coming from skeletal muscle, since it is one of the largest organs in the human body. Although it is well established that skeletal muscle secretes peptides (currently known as myokines) into the bloodstream, the notion that skeletal muscle releases EVs is in its infancy. Besides intercellular communication and systemic adaptation, EV release could represent the mechanism by which muscle adapts to certain stimuli. This review summarizes the current understanding of EV biology and biogenesis and current isolation methods and briefly discusses the possible role EVs have in regulating skeletal muscle mass.


1998 ◽  
Vol 435 (6) ◽  
pp. 753-761 ◽  
Author(s):  
C. Veigel ◽  
R. D. von Maydell ◽  
K.R. Kress ◽  
J. E. Molloy ◽  
R. H. A. Fink

1983 ◽  
Vol 96 (6) ◽  
pp. 1761-1765 ◽  
Author(s):  
M Vahey

Tomato activation inhibiting protein (AIP) is a molecule of an apparent molecular weight of 72,000 that co-purifies with tomato actin. In an assay system containing rabbit skeletal muscle F-actin and rabbit skeletal muscle myosin subfragment-1 (myosin S-1), tomato AIP dissociated the acto-S-1 complex in the absence of Mg+2ATP and inhibited the ability of F-actin to activate the low ionic strength Mg+2ATPase activity of myosin S-1. At a molar ratio of 5 actin to 1 AIP, a 50% inhibition of the actin-activated Mg+2ATPase activity of myosin S-1 was observed. The inhibition can be reversed by raising the calcium ion concentration to 1 X 10(-5) M. The AIP had no effect on the basal low ionic strength Mg+2ATPase activity of myosin S-1 in the absence of actin. The protein did not bind directly to actin nor did it cause depolymerization or aggregation of F-actin but appeared, instead, to interact with the actin binding site on myosin S-1. Since AIP is a potent, reversible inhibitor of the rabbit acto-S-1 ATPase activity, it is postulated that it may be responsible for the low levels of actin activation exhibited by tomato F-actin fractions containing the AIP.


1957 ◽  
Vol 188 (2) ◽  
pp. 205-211 ◽  
Author(s):  
William R. Amberson ◽  
John I. White ◽  
Howard B. Bensusan ◽  
Sylvia Himmelfarb ◽  
Brigitte E. Blankenhorn

Δ protein, a previously unreported fibrous protein with an electrophoretic mobility greater than that of myosin, is extracted from rabbit muscle by solutions of high ionic strength. This protein forms a complex with myosin, designated as Δ-myosin. Partial purification of Δ protein is achieved by two independent methods. In the first method alcohol fractionation is used. In the second, a solution of Salyrgan is used to dissociate the precipitated Δ-myosin complex. In each method further purification is obtained by preparative electrophoresis. Neither method yields a product which is entirely homogeneous. Tropomyosin is present as a contaminant in alcohol-fractionated preparations, and has been isolated and crystallized. All efforts to derive Δ protein from the previously known fibrous proteins of muscle have failed.


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