scholarly journals Intracellular Calcium Movements of Frog Skeletal Muscle during Recovery from Tetanus

1968 ◽  
Vol 51 (1) ◽  
pp. 65-83 ◽  
Author(s):  
Saul Winegrad
Keyword(s):  
Skeletal Muscle ◽  
Electrical Stimulation ◽  
Skeletal Muscles ◽  
Room Temperature ◽  
Complete Recovery ◽  
Mechanical Activity ◽  
Tetanic Stimulation ◽  
Frog Skeletal Muscle ◽  
Fixation Techniques ◽  
Terminal Cisternae

Radioautographs of 45Ca-labeled frog skeletal muscles have been prepared using freeze-dry and vapor fixation techniques to avoid displacement of the isotope during the preparation of the radioautographs. 45Ca has been localized in resting muscles exposed to 45Ca Ringer's for 5 min or 5 hr and in isotopically labeled muscles recovering from tetanic stimulation at room temperature or at 4°C. In muscles soaked at rest for 5 min 45Ca was present almost exclusively in the terminal cisternae. In all other muscles there were three sites at which the isotope was concentrated: (a) the terminal cisternae, (b) the intermediate cisternae and the longitudinal tubules, and (c) the A band portion of the myofibrils. The terminal cisternae were labeled more rapidly than the myofibrils, but both exchanges were accelerated by electrical stimulation. The amount of 45Ca in the longitudinal tubules and the intermediate cisternae decreased with time after a tetanus as the amount in the terminal cisternae increased. It is proposed that electrical stimulation releases calcium from the terminal cisternae and that relaxation occurs from the binding of the released calcium by the longitudinal tubules and the intermediate cisternae. Complete recovery from mechanical activity involves the transport of this bound calcium into the reticulum and its subsequent binding by the terminal cisternae. Resting exchange of calcium occurs primarily between the terminal cisternae and the transverse tubules.

scholarly journals The Intracellular Site of Calcium Activation of Contraction in Frog Skeletal Muscle

1970 ◽  
Vol 55 (1) ◽  
pp. 77-88 ◽  
Author(s):  
Saul Winegrad
Keyword(s):  
Skeletal Muscle ◽  
Room Temperature ◽  
Half Time ◽  
Frog Skeletal Muscle ◽  
Calcium Efflux ◽  
Transverse Tubules ◽  
Calcium Activation ◽  
Thin Filaments ◽  
Almost All ◽  
Terminal Cisternae

Radioautography has been used to localize 45Ca in isotopically labeled frog skeletal muscle fibers which had been quickly frozen during a maintained tetanus, a declining tetanus, or during the period immediately following a tetanus or a contracture. During a tetanus almost all of the myofibrillar 45Ca is localized in the region of the sarcomere occupied by the thin filaments. The amount varies with the tension being developed by the muscle. The movement of calcium within the reticulum from the tubular portion to the terminal cisternae during the posttetanic period has a half-time of about 9 sec at room temperature and a Q10 of about 1.7. Repolarization is not necessary for this movement. Evidence is given to support the notion that most calcium efflux from the cell occurs from the terminal cisternae into the transverse tubules.

Effect of muscle length on 45Ca efflux in resting and contracting skeletal muscle

1976 ◽  
Vol 231 (2) ◽  
pp. 555-559 ◽  
Author(s):  
JS Frank ◽  
S Winegrad
Keyword(s):  
Skeletal Muscle ◽  
Electrical Stimulation ◽  
Action Potentials ◽  
Slow Component ◽  
Morphological Changes ◽  
Muscle Length ◽  
Frog Skeletal Muscle ◽  
45Ca Efflux ◽  
Terminal Cisternae

The increment of the slow component of 45Ca efflux from frog skeletal muscle that is produced by electrical stimulation is reduced by 70% when the muscle has been stretched to 160% of in vivo length. No change in the efflux from resting muscles or the increment in influx associated with stimulation was produced by increased length. The increased efflux produced by 8 mM caffeine was not altered by increased muscle length. Resting and action potentials were unchanged by the stretching. No morphological changes were seen in the transverse tubules or their junction with the terminal cisternae even at sarcomere lengths of 3.8 muM, but the terminal cisternae themselves were elongated at this length.

scholarly journals Bioengineered in vitro skeletal muscles as new tools for muscular dystrophies preclinical studies

2021 ◽  
Vol 12 ◽  
pp. 204173142098133
Author(s):  
Juan M. Fernández-Costa ◽  
Xiomara Fernández-Garibay ◽  
Ferran Velasco-Mallorquí ◽  
Javier Ramón-Azcón
Keyword(s):  
Skeletal Muscle ◽  
Tissue Engineering ◽  
Electrical Stimulation ◽  
Skeletal Muscles ◽  
Screening Tools ◽  
Muscular Dystrophies ◽  
Preclinical Studies ◽  
Technological Advances ◽  
Topographical Cues

Muscular dystrophies are a group of highly disabling disorders that share degenerative muscle weakness and wasting as common symptoms. To date, there is not an effective cure for these diseases. In the last years, bioengineered tissues have emerged as powerful tools for preclinical studies. In this review, we summarize the recent technological advances in skeletal muscle tissue engineering. We identify several ground-breaking techniques to fabricate in vitro bioartificial muscles. Accumulating evidence shows that scaffold-based tissue engineering provides topographical cues that enhance the viability and maturation of skeletal muscle. Functional bioartificial muscles have been developed using human myoblasts. These tissues accurately responded to electrical and biological stimulation. Moreover, advanced drug screening tools can be fabricated integrating these tissues in electrical stimulation platforms. However, more work introducing patient-derived cells and integrating these tissues in microdevices is needed to promote the clinical translation of bioengineered skeletal muscle as preclinical tools for muscular dystrophies.

scholarly journals Sizes of components in frog skeletal muscle measured by methods of stereology.

1975 ◽  
Vol 66 (1) ◽  
pp. 31-45 ◽  
Author(s):  
B A Mobley ◽  
B R Eisenberg
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Surface Area ◽  
Volume Ratio ◽  
Sartorius Muscle ◽  
Morphological Parameters ◽  
Frog Skeletal Muscle ◽  
Fiber Volume ◽  
Transverse Tubules ◽  
Terminal Cisternae

Stereological techniques of point and intersection counting were used to measure morphological parameters from light and electron micrographs of frog skeletal muscle. Results for sartorius muscle are as follows: myofibrils comprise 83% of fiber volume; their surface to volume ratio is 3.8 mum-1. Mitochondria comprise 1.6% of fiber volume. Transverse tubules comprise 0.32% of fiber volume, and their surface area per volume of fiber is 0.22 mum-1. Terminal cisternae of the sarcoplasmic reticulum comprise 4.1% of fiber volume; their surface area per volume of fiber is 0.54 mum-1. Longitudinal sarcoplasmic reticullum comprises 5.0% of fiber volume, and its surface area per volume of fiber is 1.48 mum-1. Longitudinal bridges between terminal cisternae on either side of a Z disk were observed infrequently; they make up only 0.035% of fiber volume and their surface area per volume of fiber is 0.009 mum-1. T-SR junction occurs over 67% of the surface of transverse tubules and over 27% of the surface of terminal cisternae. The surface to volume ratio of the caveolae is 48 mum-1; caveolae may increase the sarcolemmal surface area by 47%. Essentially the same results were obtained from semitendinosus fibers.

Quantitative x-ray elemental imaging in stimulated single intact skeletal muscle fibers: The fate of calcium in the presence of ryanodine

1988 ◽  
Vol 46 ◽  
pp. 90-91
Author(s):  
J. Sommer ◽  
P. Ingram ◽  
A. LeFurgey ◽  
R. Nassar ◽  
T. High
Keyword(s):  
Skeletal Muscle ◽  
Electrical Stimulation ◽  
Time Course ◽  
Imaging System ◽  
Quantitative Imaging ◽  
Muscle Fibers ◽  
Frog Skeletal Muscle ◽  
X Ray ◽  
Skeletal Muscle Fibers ◽  
Freeze Dried

We are involved in a continuing series of experiments aimed at a complete description,in terms of morphology and quantitative topochemistry, of the time course of spatial distributions of physiologically important elements during excitation-contraction coupling (ECC) at different time intervals (fractions of msec) following electrical stimulation of single, intact frog skeletal muscle fibers. In this present study wg report such distributions for Ca after 1,2 and 3 min of electrical stimulation in the presence of 2x10-4 M ryanodine, an alkaloid that, in time, causes irreversible muscle contractures.Single, intact frog skeletal muscle fibers were quick-frozen, cryosectioned, freeze-substituted and in one case freeze-fractured. The freeze-dried cryosections were subjected to electron probe X-ray microanalysis (EPXMA) in a JEOL 1200EX analytical electron microscope equipped with a Tracor Northern X-ray detector and a fully quantitative imaging system. Both, 64/64 pixel images (ambient temp.), and small raster probes (cold stage,-115 °C) for better statistics, were obtained, each from the same section.

Role of Parvalbumin in Skeletal Muscle Relaxation

Physiology ◽  
1996 ◽  
Vol 11 (6) ◽  
pp. 249-255 ◽  
Author(s):  
JA Rall
Keyword(s):  
Skeletal Muscle ◽  
Skeletal Muscles ◽  
Muscle Relaxation ◽  
Calcium Pump ◽  
Frog Skeletal Muscle ◽  
Animal Kingdom ◽  
Calcium Buffer ◽  
High Concentrations ◽  
Sarcoplasmic Reticulum Calcium

Parvalbumin, a soluble intracellular calcium buffer, is present in high concentrations in fast-contracting skeletal muscles across the animal kingdom. In frog skeletal muscle, pharmacological or low-temperature inhibition of the sarcoplasmic reticulum calcium pump reveals that parvalbumin sequesters calcium and promotes relaxation at a rate determined by magnesium dissociation from parvalbumin.

scholarly journals Effects of previous activity on the energetics of activation in frog skeletal muscle.

1980 ◽  
Vol 75 (6) ◽  
pp. 617-631 ◽  
Author(s):  
J A Rall
Keyword(s):  
Skeletal Muscle ◽  
Time Delay ◽  
Time Course ◽  
Frog Skeletal Muscle ◽  
Active Force ◽  
Force Development ◽  
Uptake Sites ◽  
Contractile Activation ◽  
Terminal Cisternae ◽  
Activation Heat

Effects of previous activity on the ability of frog skeletal muscle at 0 degrees C to liberate energy associated with contractile activation, i.e., activation heat (AH), have been examined. Earlier work suggests that activation heat amplitude (as measured from muscles stretched to lengths where active force development is nearly abolished) is related to the amount of Ca2+ released upon stimulation. After a twitch, greater than 2 s is required before a second stimulus (AHt) can liberate the same activation heat as a first stimulus (AH infinity), i.e., (AHt)/(AH infinity) = 1 -0.83 e-1.40t, where t is time in seconds. Caffeine introduces a time delay in the recovery of the ability to generate activation heat after a twitch. After a tetanus, the activation heat is depressed to a greater extent at any time than after a twitch. The activation heat elicited by a stimulus 1 s after a tetanus is depressed progressively with respect to tetanus duration up to 3 s. For tetani of 3, 40, and 80 s duration the postetanus activation heat is comparably depressed. The time-course of the recovery of the ability of the muscle to produce activation heat after a tetanus can be described as (AHt)/(AH infinity) = 1 -0.80 e-0.95t -0.20 e-0.02t. Greater than 90 s is required before the posttetanus activation heat is equal to the pretetanus value. The faster phase of recovery is similar to recovery after the twitch and the slower phase may be associated with the return of calcium to the terminal cisternae from uptake sites in the longitudinal sarcoplasmic reticulum.

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