Membrane Resting Potential of Denervated Mammalian Skeletal Muscle Measured in Vivo

1954 ◽  
Vol 177 (1) ◽  
pp. 115-118 ◽  
Author(s):  
F. Ware ◽  
A. L. Bennett ◽  
A. R. McIntyre
Keyword(s):  
Skeletal Muscle ◽  
Resting Potential ◽  
Mammalian Skeletal Muscle ◽  
Membrane Resting Potential

In vivo supraspinatus muscle contractility and architecture in rabbit

2020 ◽  
Vol 129 (6) ◽  
pp. 1405-1412
Author(s):  
Sydnee A. Hyman ◽  
Mackenzie B. Norman ◽  
Shanelle N. Dorn ◽  
Shannon N. Bremner ◽  
Mary C. Esparza ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Isometric Force ◽  
Muscle Physiology ◽  
Mammalian Skeletal Muscle ◽  
Improved Method ◽  
Muscle Contractility ◽  
Supraspinatus Muscle ◽  
Contractile Stress ◽  
Maximum Isometric Force

We introduce an improved method to assess rabbit supraspinatus muscle physiology. Maximum isometric force measured for the rabbit supraspinatus was dramatically greater than previous reports in the literature. Consequently, the isometric contractile stress reported is almost 10 times greater than previous reports of rabbit supraspinatus, but similar to available literature of other mammalian skeletal muscle. We show that previous reports of peak supraspinatus isometric force were subphysiological by ∼90%

THE APPARENT EXTRACELLULAR SPACE OF MAMMALIAN SKELETAL MUSCLE: A COMPARISON OF THE INULIN SPACE IN NORMAL AND DYSTROPHIC MOUSE TISSUES

1960 ◽  
Vol 38 (8) ◽  
pp. 829-835 ◽  
Author(s):  
L. H. Burr ◽  
H. McLennan
Keyword(s):  
Skeletal Muscle ◽  
Normal Tissue ◽  
Muscle Size ◽  
Mammalian Skeletal Muscle ◽  
Normal Tissues ◽  
Mouse Tissues ◽  
Inulin Space ◽  
Excised Tissues ◽  
Dystrophic Mice

The apparent extracellular volumes of the muscles from young normal and dystrophic mice have been estimated, using inulin dilution techniques. The inulin spaces were measured in the muscle both following injection of inulin in vivo and after soaking of excised tissues in a solution containing inulin. Comparisons were made between muscles of different size from the same animal as well as from different animals whose age, and consequently muscle size, varied. In all cases it has been found that the inulin space decreases with increasing muscle size. Similar results have been obtained by others with toad sartorii. The inulin space in muscles from dystrophic mice is larger than that of comparable normal tissues, and the dependence on muscle size, although similar to normal, is more pronounced. The results suggest that the dystrophic cells are permeable to inulin, and the question that some small permeability may be present also in normal tissue is considered.

scholarly journals Muscle-Derived Extracellular Signal-Regulated Kinases 1 and 2 Are Required for the Maintenance of Adult Myofibers and Their Neuromuscular Junctions

2015 ◽  
Vol 35 (7) ◽  
pp. 1238-1253 ◽  
Author(s):  
Bonnie Seaberg ◽  
Gabrielle Henslee ◽  
Shuo Wang ◽  
Ximena Paez-Colasante ◽  
Gary E. Landreth ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Tibialis Anterior ◽  
Neuromuscular Junctions ◽  
Germ Line ◽  
Fiber Type ◽  
Postnatal Growth ◽  
Mammalian Skeletal Muscle ◽  
Neuromuscular Synapses ◽  
Extracellular Signal

The Ras–extracellular signal-regulated kinase 1 and 2 (ERK1/2) pathway appears to be important for the development, maintenance, aging, and pathology of mammalian skeletal muscle. Yet no gene targeting ofErk1/2in muscle fibersin vivohas been reported to date. We combined a germ lineErk1mutation with Cre-loxPErk2inactivation in skeletal muscle to produce, for the first time, mice lacking ERK1/2 selectively in skeletal myofibers. Animals lacking muscle ERK1/2 displayed stunted postnatal growth, muscle weakness, and a shorter life span. Their muscles examined in this study, sternomastoid and tibialis anterior, displayed fragmented neuromuscular synapses and a mixture of modest fiber atrophy and loss but failed to show major changes in fiber type composition or absence of cell surface dystrophin. Whereas the lack of only ERK1 had no effects on the phenotypes studied, the lack of myofiber ERK2 explained synaptic fragmentation in the sternomastoid but not the tibialis anterior and a decrease in the expression of the acetylcholine receptor (AChR) epsilon subunit gene mRNA in both muscles. A reduction in AChR protein was documented in line with the above mRNA results. Evidence of partial denervation was found in the sternomastoid but not the tibialis anterior. Thus, myofiber ERK1/2 are differentially required for the maintenance of myofibers and neuromuscular synapses in adult mice.

scholarly journals Purification of desmin from adult mammalian skeletal muscle

1981 ◽  
Vol 195 (2) ◽  
pp. 345-356 ◽  
Author(s):  
J M O'Shea ◽  
R M Robson ◽  
M K Hartzer ◽  
T W Huiatt ◽  
W E Rathbun ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Average Diameter ◽  
Intermediate Filament Protein ◽  
Mammalian Skeletal Muscle ◽  
Cytoskeletal Function ◽  
10 Nm Filaments ◽  
And Function ◽  
Filament Protein

A method has been developed for preparation of purified desmin from mature mammalian (porcine) skeletal muscle. A crude desmin-containing fraction was prepared by modification of procedures used for isolation of smooth-muscle intermediate-filament protein [Small & Sobieszek (1977) J. Cell Sci. 23, 243-268]. The desmin was extracted in 1 M-acetic acid/20 mM-NaCl at 4 degrees C for 15h from the residue remaining after actomyosin extraction from washed myofibrils. Successive chromatography on hydroxyapatite and DEAE-Sepharose CL-6B in 6M-urea yielded desmin that was routinely more than 97% 55 000-dalton protein and that had no detectable actin contamination. Removal of urea by dialysis against 10mM-Tris/acetate (pH 8.5)/1 mM dithioerythritol and subsequent clarification at 134 000 g (rav. 5.9 cm) for 1 h results in a clear desmin solution. Dialysis of purified desmin against 100 mM-NaCl/1 mM-MgCl2/10 mM-imidazole/HCl, pH 7.0, at 2 degrees C resulted in the formation of synthetic desmin filaments have an average diameter of 9-11.5 nm. The present studies demonstrate that the relatively small amount of desmin in mature skeletal muscle can be isolated in sufficient quantity and purity to permit detailed studies of its properties and function. Although 10nm filaments have not been unequivocally demonstrated in mature muscle in vivo, that the purified skeletal-muscle desmin will form 10 nm filaments in vitro lends support to their possible existence and cytoskeletal function in mature skeletal-muscle cells.

scholarly journals Long-chain n-3 DHA reduces the extent of skeletal muscle fatigue in the rat in vivo hindlimb model

2013 ◽  
Vol 111 (6) ◽  
pp. 996-1003 ◽  
Author(s):  
Gregory E. Peoples ◽  
Peter L. McLennan
Keyword(s):  
Skeletal Muscle ◽  
Fish Oil ◽  
Muscle Fatigue ◽  
Muscle Membrane ◽  
Mammalian Skeletal Muscle ◽  
Skeletal Muscle Fatigue ◽  
Arterial Blood ◽  
Oxygen Efficiency ◽  
Long Chain

Dietary fish oil modifies skeletal muscle membrane fatty acid composition and oxygen efficiency similar to changes in the myocardium. Oxygen efficiency is a key determinant of sustained force in mammalian skeletal muscle. Therefore, in the present study, we tested the effects of a fish-oil diet on skeletal muscle fatigue under the stress of contraction using the rat in vivo autologous perfused hindlimb model. For 8 weeks, male Wistar rats were fed a diet rich in saturated fat (SF), a diet rich in n-6 PUFA or a diet rich in long-chain (LC) n-3 PUFA DHA derived from fish oil. In anaesthetised, mechanically ventilated rats, with their hindlimbs perfused with arterial blood at a constant flow, the gastrocnemius–plantaris–soleus muscle bundle was stimulated via sciatic nerve (2 Hz, 6–12 V, 0·05 ms) to contract repetitively for 30 min. Rats fed the n-3 PUFA diet developed higher maximum twitch tension than those fed the SF and n-6 PUFA diets (P< 0·05) and sustained twitch tension through more repetitions before the tension declined to 50 % of the maximum twitch tension (P< 0·05). The n-3 PUFA group used less oxygen for tension developed and produced higher venous lactate concentrations with no difference in glycogen utilisation compared with the SF and n-6 PUFA groups. These results further support that incorporation of DHA into skeletal muscle membranes increases the efficiency of oxygen use over a range of contractile force and this is expressed as a higher sustained force and prolonged time to fatigue.

scholarly journals Resting Potential–dependent Regulation of the Voltage Sensitivity of Sodium Channel Gating in Rat Skeletal Muscle In Vivo

2005 ◽  
Vol 126 (2) ◽  
pp. 161-172 ◽  
Author(s):  
Gregory N. Filatov ◽  
Martin J. Pinter ◽  
Mark M. Rich
Keyword(s):  
Skeletal Muscle ◽  
Sodium Channel ◽  
Voltage Dependence ◽  
Channel Gating ◽  
Resting Potential ◽  
Sodium Currents ◽  
Fast Inactivation ◽  
Adult Skeletal Muscle ◽  
Muscle Excitability

Normal muscle has a resting potential of −85 mV, but in a number of situations there is depolarization of the resting potential that alters excitability. To better understand the effect of resting potential on muscle excitability we attempted to accurately simulate excitability at both normal and depolarized resting potentials. To accurately simulate excitability we found that it was necessary to include a resting potential–dependent shift in the voltage dependence of sodium channel activation and fast inactivation. We recorded sodium currents from muscle fibers in vivo and found that prolonged changes in holding potential cause shifts in the voltage dependence of both activation and fast inactivation of sodium currents. We also found that altering the amplitude of the prepulse or test pulse produced differences in the voltage dependence of activation and inactivation respectively. Since only the Nav1.4 sodium channel isoform is present in significant quantity in adult skeletal muscle, this suggests that either there are multiple states of Nav1.4 that differ in their voltage dependence of gating or there is a distribution in the voltage dependence of gating of Nav1.4. Taken together, our data suggest that changes in resting potential toward more positive potentials favor states of Nav1.4 with depolarized voltage dependence of gating and thus shift voltage dependence of the sodium current. We propose that resting potential–induced shifts in the voltage dependence of sodium channel gating are essential to properly regulate muscle excitability in vivo.

Regulation of phosphatidylinositol 3-kinase by insulin in rat skeletal muscle

1993 ◽  
Vol 265 (5) ◽  
pp. E736-E742 ◽  
Author(s):  
K. S. Chen ◽  
J. C. Friel ◽  
N. B. Ruderman
Keyword(s):  
Skeletal Muscle ◽  
Soleus Muscle ◽  
Protein Tyrosine Kinase ◽  
Kinase Activity ◽  
Receptor Protein ◽  
Mammalian Skeletal Muscle ◽  
Phosphatidylinositol 3 Kinase ◽  
Phosphatidylinositol 3

The presence of phosphatidylinositol 3-kinase (PI 3-kinase) in mammalian skeletal muscle and its response to insulin stimulation were investigated. PI kinase, immunoprecipitated from rat soleus muscle with antibodies directed toward its 85-kDa subunit phosphorylated PI, phosphatidylinositol 4-phosphate [PI(4)P], and phosphatidylinositol 4,5,-bisphosphate [PI(4,5)P2] to yield phosphatidylinositol 3-phosphate [PI(3)P], phosphatidylinositol 3,4,-bisphosphate, and phosphatidylinositol trisphosphate in vitro. PI 3-kinase activity was also immunoprecipitated with antiphosphotyrosine [alpha-Tyr(P)] antibodies and with antibodies raised against IRS-1, a substrate of the insulin receptor protein tyrosine kinase that associates with and activates PI 3-kinase. Incubation of the soleus with insulin in vitro, or injection of insulin into rats in vivo, produced three- to fivefold increases in alpha-Tyr(P)- and alpha-IRS-1-immunoprecipitable PI 3-kinase activity. In nonstimulated soleus muscle, PI 3-kinase activity immunoprecipitated with alpha-IRS-1 or with alpha-Tyr(P) antibodies was evenly distributed between particulate (200,000-g pellet) and soluble fractions. Insulin treatment increased immunoprecipitable PI 5-kinase activity in both fractions, but the increase in alpha-Tyr-(P)-precipitable activity was greater in the particulate fraction, whereas the increase in alpha-IRS-1-precipitable activity was greater in the soluble fraction. In intact soleus muscles incubated with 32PO4, insulin increased the labeling of PI(3)P but did not affect the labeling of PI(4)P or PI(4,5)P2. Activation of PI 3-kinase by insulin was unaffected by prior denervation of the muscle, a manipulation that has been shown to cause both insulin resistance and hypersensitivity in muscles, depending on the parameter measured.(ABSTRACT TRUNCATED AT 250 WORDS)

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