scholarly journals Ca-ATPase isozyme expression in sarcoplasmic reticulum is altered by chronic stimulation of skeletal muscle

FEBS Letters ◽  
1990 ◽  
Vol 259 (2) ◽  
pp. 269-272 ◽  
Author(s):  
F.Norman Briggs ◽  
K.Francis Lee ◽  
Joseph J. Feher ◽  
Andrew S. Wechsler ◽  
Kay Ohiendieck ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Chronic Stimulation ◽  
Stimulation Of

Ca2+ Uptake Coupled to Glycogen Phosphorolysis in the Glycogenolytic-Sarcoplasmic Reticulum Complex from Rat Skeletal Muscle

1996 ◽  
Vol 51 (7-8) ◽  
pp. 591-598 ◽  
Author(s):  
M. Nogues ◽  
A. Cuenda ◽  
F. Henao ◽  
C. Gutiérrez-Merino
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Glycogen Phosphorylase ◽  
Rat Skeletal Muscle ◽  
Subcellular Structure ◽  
Sequential Action ◽  
Physiological Conditions ◽  
Low Concentrations ◽  
Ischemic Muscle ◽  
Stimulation Of

Abstract The glycogenolytic-sarcoplasmic reticulum complex from rat skeletal muscle accumulates Ca2+ upon stimulation of glycogen phosphorolysis in the absence of added ATP. It is shown that an efficient Ca2+ uptake involves the sequential action of glycogen phosphorylase, phosphoglucomutase and hexokinase, which generate low concentrations of ATP (approximately 1 -2 μм) compartmentalized in the immediate vicinity of the sarcoplasmic reticulum Ca2+, Mg2+-ATPase (the Ca2+ pump). The Ca2+ uptake supported by glycogenolysis in this subcellular structure is strongly stimulated by micromolar concentrations of AMP, showing that the glycogen phosphorylase associated with this complex is in the dephosphorylated b form. The results point out that the flux through this compartmentalized metabolic pathway should be enhanced in physiological conditions leading to increased AMP concentrations in the sarcoplasm, such as long-lasting contractions and in ischemic muscle.

Ca(2+)- and pH-dependent halothane stimulation of Ca2+ release in sarcoplasmic reticulum from frog muscle

1996 ◽  
Vol 271 (2) ◽  
pp. C540-C546 ◽  
Author(s):  
M. Beltran ◽  
R. Bull ◽  
P. Donoso ◽  
C. Hidalgo
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Calcium Release ◽  
Release Kinetics ◽  
Frog Muscle ◽  
Time Range ◽  
Frog Skeletal Muscle ◽  
Open Probability ◽  
Filtration System ◽  
Stimulation Of

The effect of halothane on calcium release kinetics was studied in triad-enriched sarcoplasmic reticulum vesicles from frog skeletal muscle. Release from vesicles passively equilibrated with 3 mM 45CaCl2 was measured in the millisecond time range by use of a fast-filtration system. Halothane (400 microM) increased release rate constants at pH 7.1 and 7.4 as a function of extravesicular pCa. In contrast, halothane at pH 6.8 produced the same stimulation of release from pCa 7.0 to 3.0; no release took place in these conditions in the absence of halothane. Halothane shifted the calcium activation curve at pH 7.1, but not at pH 7.4, to the left and increased channel open probability at pH 7.1 in the cis pCa range of 7.0 to 5.0. These results indicate that cytosolic pCa and pH modulate the stimulatory effects of halothane on calcium release. Furthermore, halothane stimulated release in frog skeletal muscle at low pH and resting calcium concentration, indicating that in frog muscle halothane can override the closing of the release channels produced by these conditions, as it does in malignant hyperthermia-susceptible porcine muscle.

scholarly journals Effect of guanosine triphosphate on the release and uptake of Ca2+ in saponin-permeabilized macrophages and the skeletal-muscle sarcoplasmic reticulum

1987 ◽  
Vol 242 (1) ◽  
pp. 253-260 ◽  
Author(s):  
T Hamachi ◽  
M Hirata ◽  
Y Kimura ◽  
T Ikebe ◽  
T Ishimatsu ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Steady State ◽  
Polyethylene Glycol ◽  
Sarcoplasmic Reticulum ◽  
Sustained Release ◽  
Skeletal Muscles ◽  
Guanosine Triphosphate ◽  
Uptake Activity ◽  
Releasing Effect ◽  
Stimulation Of

The effects of GTP, with or without polyethylene glycol (PEG), on the release and uptake of Ca2+ were examined by using saponin-treated macrophages and sarcoplasmic reticulum isolated from skeletal muscles. The application of GTP in concentrations in the range 0.1-10 microM induced a gradual, small but sustained release of Ca2+ from the saponin-treated macrophages. The addition of PEG to GTP markedly enhanced the GTP-mediated Ca2+ release. GTP at the same concentration ranges used for Ca2+ release decreased the amount of Ca2+ uptake, at a steady state, but stimulated the rate of Ca2+ accumulation in the presence of oxalate, the Ca2+-precipitating anion. The addition of PEG abolished the GTP-evoked stimulation of Ca2+ accumulation in the presence of oxalate. The stimulating effect on the rate of Ca2+ accumulation by GTP and its elimination by PEG were not due to changes in the permeability of oxalate by either GTP or PEG, or both. The Ca2+-releasing effect of GTP without PEG was enhanced by eliminating the uptake activity by decreasing the content of ATP. These results indicate that GTP has an inherent activity to release Ca2+ from non-mitochondrial intracellular stores of saponin-treated macrophages, and PEG enhances the GTP-mediated Ca2+ release, partly owing to its eliminating effect on GTP-stimulated Ca2+ uptake activity. These effects of GTP observed with saponin-permeabilized macrophages were not apparent in the isolated skeletal-muscle sarcoplasmic reticulum.

Mechanisms of stimulated 45Ca efflux in skinned skeletal muscle fibers

1987 ◽  
Vol 65 (4) ◽  
pp. 632-641 ◽  
Author(s):  
Elizabeth W. Stephenson
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Calcium Release ◽  
Isometric Force ◽  
Signal Transmission ◽  
Transverse Tubules ◽  
Transverse Tubule ◽  
Ion Gradients ◽  
Charge Movements ◽  
Stimulation Of

Excitation–contraction (E–C) coupling in skeletal muscle can be studied in skinned fibers by direct assay of 45Ca efflux and simultaneous isometric force, under controlled conditions. Recent work provides evidence that such studies can address major current questions about the mechanisms of signal transmission between transverse tubules and sarcoplasmic reticulum and sarcoplasmic reticulum calcium release, as well as operation of the sarcoplasmic reticulum active Ca transport system in situ. Stimulation by imposed ion gradients at constant [K+][Cl−] product results in 45Ca release with two components: a large Ca2+-dependent efflux, responsible for contractile activation, and a small Ca2+-insensitive efflux. The Ca2+-insensitive stimulation is sustained, consistent with sustained depolarization, and appears to gradate the Ca2+-dependent stimulation; this component is likely to reflect intermediate steps in E–C coupling. Several lines of evidence suggest that the depolarizing stimulus acts on the transverse tubules. It is inhibited by the impermeant glycoside ouabain applied before skinning, which should specifically inhibit polarization of subsequently sealed transverse tubules. Sealed polarized transverse tubules also are the only plausible target for stimulation of 45Ca release by monensin and gramicidin D, which can rapidly dissipate Na+ and K+ gradients; a protonophore and the K+-specific ionophore valinomycin are ineffective, lonophore stimulation is prevented by the permeant glycoside digitoxin; it is also highly Ca2+ dependent. Stimulation of 45Ca release by imposed ion gradients is potentiated by perchlorate, which potentiates charge movements and activation in intact fibers, and is inhibited selectively in highly stretched fibers, presumably by transverse tubule – sarcoplasmic reticulum uncoupling. These results relate the Ca2+-dependent sarcoplasmic reticulum efflux channel to the physiological transverse tubule – sarcoplasmic reticulum coupling pathway, which also could involve Ca2+.

Quercetin stimulation of calcium release from rabbit skeletal muscle sarcoplasmic reticulum

Life Sciences ◽  
1983 ◽  
Vol 32 (3) ◽  
pp. 213-219 ◽  
Author(s):  
James Watras ◽  
Sharon Glezen ◽  
Christina Seifert ◽  
Arnold M. Katz
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Calcium Release ◽  
Rabbit Skeletal Muscle ◽  
Stimulation Of

scholarly journals Ca2+ dependence of transverse tubule-mediated calcium release in skinned skeletal muscle fibers.

1986 ◽  
Vol 87 (2) ◽  
pp. 271-288 ◽  
Author(s):  
P Volpe ◽  
E W Stephenson
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Calcium Release ◽  
Muscle Fibers ◽  
Transverse Tubule ◽  
Force Development ◽  
Skeletal Muscle Fibers ◽  
Gramicidin D ◽  
45Ca Efflux ◽  
Stimulation Of

Isometric force and 45Ca efflux from the sarcoplasmic reticulum were measured at 19 degrees C in frog skeletal muscle fibers skinned by microdissection. After Ca2+ loading, application of the ionophores monensin, an Na+(K+)/H+ exchanger, or gramicidin D, an H+ greater than K+ greater than Na+ channel-former, evoked rapid force development and stimulated release of approximately 30% of the accumulated 45Ca within 1 min, whereas CCCP (carbonyl cyanide pyruvate p-trichloromethoxyphenylhydrazone), a protonophore, and valinomycin, a neutral, K+-specific ionophore, did not. When monensin was present in all bathing solutions, i.e., before and during Ca2+ loading, subsequent application failed to elicit force development and to stimulate 45Ca efflux. 5 min pretreatment of the skinned fibers with 50 microM digitoxin, a permeant glycoside that specifically inhibits the Na+,K+ pump, inhibited monensin and gramicidin D stimulation of 45Ca efflux; similar pretreatment with 100 microM ouabain, an impermeant glycoside, was ineffective. Monensin stimulation of 45Ca efflux was abolished by brief pretreatment with 5 mM EGTA, which chelates myofilament-space calcium. These results suggest that: monensin and gramicidin D stimulate Ca2+ release from the sarcoplasmic reticulum that is mediated by depolarization of the transverse tubules, which seal off after sarcolemma removal and form closed compartments; a transverse tubule membrane potential (myofilament space-negative) is maintained and/or established by the operation of the Na+,K+ pump in the transverse tubule membranes and is sensitive to the permeant inhibitor digitoxin; the transverse tubule-mediated stimulation of 45Ca efflux appears to be entirely Ca2+ dependent.

Skeletal muscle sarcoplasmic reticulum contains a NADH-dependent oxidase that generates superoxide

2003 ◽  
Vol 285 (1) ◽  
pp. C215-C221 ◽  
Author(s):  
Ruohong Xia ◽  
Jason A. Webb ◽  
Lisa L. M. Gnall ◽  
Kerry Cutler ◽  
Jonathan J. Abramson
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Nadh Oxidase ◽  
Release Mechanism ◽  
Antimycin A ◽  
High Affinity ◽  
Diphenylene Iodonium ◽  
Nadh Oxidase Activity ◽  
Terminal Cisternae ◽  
Stimulation Of

Skeletal muscle sarcoplasmic reticulum (SR) is shown to contain an NADH-dependent oxidase (NOX) that reduces molecular oxygen to generate superoxide. Its activity is coupled to an activation of the Ca2+ release mechanism, as evident by stimulation in the rate of high-affinity ryanodine binding. NOX activity, coupled to the production of superoxide, is not derived from the mitochondria but is SR in origin. The SR preparation also contains a significant NADH oxidase activity, which is not coupled to the production of superoxide and appears to be mitochondrial in origin. This mitochondrial component is preferentially associated with the terminal cisternae region of the SR. Its activity is inhibited by diphenylene iodonium (10 μM), antimycin A (200 nM), and rotenone (40 nM) but is not coupled to the generation of superoxide or the stimulation of the ryanodine receptor. The rate of superoxide production per milligram of protein is larger in SR than in mitochondria. This NOX may be a major source of oxidative stress in muscle.

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