scholarly journals Efflux Time Courses of Cytosolic Proteins from Rabbit Skinned Muscle Fibers Reflect Dissociation of Enzyme Complexes

2014 ◽  
Vol 106 (2) ◽  
pp. 56a
Author(s):  
David Maughan ◽  
Brian Carlson ◽  
Jim Vigoreaux
Keyword(s):  
Muscle Fibers ◽  
Cytosolic Proteins ◽  
Skinned Muscle ◽  
Skinned Muscle Fibers ◽  
Time Courses ◽  
Efflux Time ◽  
Enzyme Complexes

scholarly journals Diffusion Coefficients of Endogenous Cytosolic Proteins from Rabbit Skinned Muscle Fibers

2014 ◽  
Vol 106 (4) ◽  
pp. 780-792 ◽  
Author(s):  
Brian E. Carlson ◽  
Jim O. Vigoreaux ◽  
David W. Maughan
Keyword(s):  
Diffusion Coefficients ◽  
Muscle Fibers ◽  
Cytosolic Proteins ◽  
Skinned Muscle ◽  
Skinned Muscle Fibers

scholarly journals Excitation of skinned muscle fibers by imposed ion gradients. I. Stimulation of 45Ca efflux at constant [K][Cl] product.

1985 ◽  
Vol 86 (6) ◽  
pp. 813-832 ◽  
Author(s):  
E W Stephenson
Keyword(s):  
Isometric Force ◽  
Muscle Fibers ◽  
Water Flux ◽  
Skinned Muscle ◽  
Skinned Muscle Fibers ◽  
Diffusion Potentials ◽  
45Ca Efflux ◽  
Osmotic Effects ◽  
45Ca Release ◽  
And Diffusion

45Ca efflux from skinned muscle fibers is stimulated transiently, by a highly Ca2+-dependent mechanism, by KCl replacement of K propionate. In the present studies, Cl replaced the much less permeant anion methanesulfonate (Mes) either (a) at constant [K], in which increased [K][Cl] permits net KCl and water flux across internal membranes, or (b) at constant [K][Cl] (choline substitution), in which the imposed gradients and diffusion potentials should dissipate slowly. 45Ca efflux and isometric force were measured simultaneously on segments of frog semitendinosus fibers skinned by microdissection. EGTA was applied to chelate released 45Ca either (a) shortly after high [Cl] (interrupted response), to minimize reaccumulation, (b) before high [Cl] (pretreated response), to evaluate Ca2+ dependence, or (c) under control conditions in KMes. KCl replacement of KMes stimulated release of 65% fiber 45Ca within 1 min in interrupted responses; EGTA pretreatment was only moderately inhibitory with substantial residual stimulation. In contrast, choline Cl replacement of KMes induced release of 26-35% fiber 45Ca in interrupted responses; EGTA pretreatment was strongly inhibitory, but release significantly exceeded control with a small, sustained increase in Ca2+-insensitive efflux. These differences in 45Ca release and EGTA inhibition suggest that Cl replacement of Mes at constant [K] stimulates efflux by osmotic effects as well as imposed diffusion potentials; at least half the stimulated 45Ca loss (above control) in interrupted KCl responses is attributable to an osmotic component with low Ca2+ sensitivity. In the highly Ca2+-sensitive stimulation at constant [K][Cl], 45Ca release (above control) in interrupted responses correlated well with that in the pretreated responses of segments from the same fiber, with a slope of 8.4. This relationship suggests that imposed diffusion potentials stimulate a small Ca2+-insensitive component that gradates a much larger Ca2+-dependent efflux. The Ca2+-insensitive component apparently reflects intermediate steps in the excitation-contraction coupling that require positive feedback to result in sufficient Ca release for contraction.

Enhancement of Ca2+-induced Ca2+ release in calpain treated rabbit skinned muscle fibers

1992 ◽  
Vol 185 (2) ◽  
pp. 713-718 ◽  
Author(s):  
Masamitsu Iino ◽  
Hiromi Takano-Ohmuro ◽  
Yoko Kawana ◽  
Makoto Endo
Keyword(s):  
Muscle Fibers ◽  
Skinned Muscle ◽  
Skinned Muscle Fibers
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