scholarly journals Nonlinear summation of contractions in cat muscles. II. Later facilitation and stiffness changes.

1981 ◽  
Vol 78 (3) ◽  
pp. 295-311 ◽  
Author(s):  
F Parmiggiani ◽  
R B Stein
Keyword(s):  
Soleus Muscle ◽  
Time Course ◽  
Short Interval ◽  
Force Production ◽  
Muscle Stiffness ◽  
Contraction Time ◽  
Plantaris Muscle ◽  
Twitch Contraction ◽  
Slow Twitch ◽  
Fast Twitch

The force produced by cat muscles over time with two stimuli separated by a short interval is approximately three times that produced by a twitch of cat muscles. This facilitation of force production by a second stimulus involves both increases in magnitude and duration of the contraction. Increased magnitude is relatively more important in the fast-twitch plantaris muscle, whereas increased duration is more important in the slow-twitch soleus muscle. The facilitation decays in an approximately exponential manner with the interval between stimuli, having a time constant between one and two times the twitch contraction time in different muscles. If a third stimulus is added, the greatest facilitation is seen at intervals longer than the twitch contraction time. The drug Dantrolene, which specifically reduces Ca++ release from the sarcoplasmic reticulum, eliminates the delayed peak in facilitation with three stimuli. Associated with the increases in force with one or more stimuli are increases in muscle stiffness, which can be measured with small, brief stretches and releases that do not alter the time-course of contraction. The stiffness of soleus muscle reaches a peak after the peak in force. The increasing stiffness of the muscle can considerably facilitate transmission of force generated internally, in addition to any facilitation arising from Ca++-release mechanisms.

The stiffness of slow-twitch muscle lags behind twitch tension: Implications for contractile mechanisms and behavior

1979 ◽  
Vol 57 (10) ◽  
pp. 1189-1192 ◽  
Author(s):  
R. B. Stein ◽  
F. Parmiggiani
Keyword(s):  
Soleus Muscle ◽  
Muscle Stiffness ◽  
Plantaris Muscle ◽  
Rigor State ◽  
Slow Twitch Muscle ◽  
Slow Twitch ◽  
And Behavior

Small, square stretches were applied during contractions of soleus and plantaris muscles in the cat to measure muscle stiffness. The stiffness of the slow-twitch soleus muscle (but not of the fast plantaris muscle) reaches a maximum after the peak in twitch tension. Since the number of active bonds should be maximum before the peak in tension, we suggest that many bonds are in the rigor state during the falling phase of the twitch. The stiffness of the bonds in this state may be useful for prolonging the twitch in slow-twitch muscles and for maintaining a posture.

ATP-sensitive potassium channels mediate hyperosmotic stimulation of NKCC in slow-twitch muscle

2004 ◽  
Vol 286 (3) ◽  
pp. C586-C595 ◽  
Author(s):  
Aidar R. Gosmanov ◽  
Zheng Fan ◽  
Xianqiang Mi ◽  
Edward G. Schneider ◽  
Donald B. Thomason
Keyword(s):  
Skeletal Muscle ◽  
Soleus Muscle ◽  
Potassium Current ◽  
Plantaris Muscle ◽  
Channel Inhibition ◽  
Slow Twitch Muscle ◽  
Inhibition Of Glycolysis ◽  
Slow Twitch ◽  
Mapk Inhibitors ◽  
Fast Twitch

In mildly hyperosmotic medium, activation of the Na+-K+-2Cl- cotransporter (NKCC) counteracts skeletal muscle cell water loss, and compounds that stimulate protein kinase A (PKA) activity inhibit the activation of the NKCC. The aim of this study was to determine the mechanism for PKA inhibition of NKCC activity in resting skeletal muscle. Incubation of rat slow-twitch soleus and fast-twitch plantaris muscles in isosmotic medium with the PKA inhibitors H-89 and KT-5720 caused activation of the NKCC only in the soleus muscle. NKCC activation caused by PKA inhibition was insensitive to MEK MAPK inhibitors and to insulin but was abolished by the PKA stimulators isoproterenol and forskolin. Furthermore, pinacidil [an ATP-sensitive potassium (KATP) channel opener] or inhibition of glycolysis increased NKCC activity in the soleus muscle but not in the plantaris muscle. Preincubation of the soleus muscle with glibenclamide (a KATP channel inhibitor) prevented the NKCC activation by hyperosmolarity, PKA inhibition, pinacidil, and glycolysis inhibitors. In contrast, glibenclamide stimulated NKCC activity in the plantaris muscle. In cells stably transfected with the Kir6.2 subunit of the of KATP channel, inhibition of glycolysis activated potassium current and NKCC activity. We conclude that activation of KATP channels in slow-twitch muscle is necessary for activation of the NKCC and cell volume restoration in hyperosmotic conditions.

scholarly journals Differences in histone modifications between slow- and fast-twitch muscle of adult rats and following overload, denervation, or valproic acid administration

2015 ◽  
Vol 119 (10) ◽  
pp. 1042-1052 ◽  
Author(s):  
Fuminori Kawano ◽  
Keisuke Nimura ◽  
Saki Ishino ◽  
Naoya Nakai ◽  
Ken Nakata ◽  
...  
Keyword(s):  
Valproic Acid ◽  
Rna Polymerase Ii ◽  
Histone Modifications ◽  
Soleus Muscle ◽  
Plantaris Muscle ◽  
Adult Rats ◽  
Muscle Properties ◽  
Pol Ii ◽  
Slow Twitch ◽  
Fast Twitch

Numerous studies have reported alterations in skeletal muscle properties and phenotypes in response to various stimuli such as exercise, unloading, and gene mutation. However, a shift in muscle fiber phenotype from fast twitch to slow twitch is not completely induced by stimuli. This limitation is hypothesized to result from the epigenetic differences between muscle types. The main purpose of the present study was to identify the differences in histone modification for the plantaris (fast) and soleus (slow) muscles of adult rats. Genome-wide analysis by chromatin immunoprecipitation followed by DNA sequencing revealed that trimethylation at lysine 4 and acetylation of histone 3, which occurs at transcriptionally active gene loci, was less prevalent in the genes specific to the slow-twitch soleus muscle. Conversely, gene loci specific to the fast-twitch plantaris muscle were associated with the aforementioned histone modifications. We also found that upregulation of slow genes in the plantaris muscle, which are related to enhanced muscular activity, is not associated with activating histone modifications. Furthermore, silencing of muscle activity by denervation caused the displacement of acetylated histone and RNA polymerase II (Pol II) in 5′ ends of genes in plantaris, but minor effects were observed in soleus. Increased recruitment of Pol II induced by forced acetylation of histone was also suppressed in valproic acid-treated soleus. Our present data indicate that the slow-twitch soleus muscle has a unique set of histone modifications, which may relate to the preservation of the genetic backbone against physiological stimuli.

Effects of thyroidectomy on development of skeletal muscle in fetal sheep

1991 ◽  
Vol 261 (5) ◽  
pp. R1300-R1306 ◽  
Author(s):  
D. I. Finkelstein ◽  
P. Andrianakis ◽  
A. R. Luff ◽  
D. Walker
Keyword(s):  
Skeletal Muscle ◽  
Thyroid Gland ◽  
Extensor Digitorum Longus ◽  
Relaxation Times ◽  
Medial Gastrocnemius ◽  
Fetal Sheep ◽  
Twitch Contraction ◽  
Slow Twitch ◽  
Contraction And Relaxation ◽  
Fast Twitch

The influence of the thyroid gland on the functional and histochemical development of fast- and slow-twitch skeletal muscle of fetal sheep has been studied in euthyroid fetal sheep (n = 6) and athyroid fetuses (n = 4) surgically thyroid-ectomized at 70-75 days of gestation. Two fast-twitch muscles, the medial gastrocnemius and extensor digitorum longus, and the slow-twitch soleus muscle were studied at the fetal age of 140 days gestation. The athyroid fetuses had significantly slower twitch contraction and relaxation times in both the medial gastrocnemius and extensor digitorum longus muscles compared with the euthyroid fetuses. Twitch contraction and relaxation times of the soleus were not different in the two groups. Thyroidectomy resulted in an increase in the proportion of fast (type II) muscle fibers and myosin, as shown histochemically and by gel electrophoresis of heavy-chain myosins. These results indicate that the functional maturation of the fast-twitch muscles of sheep is influenced by the presence of an intact thyroid gland from at least 70 days of gestation. In contrast, the slow-twitch soleus muscle fiber diameter and twitch contraction and relaxation times were not different in the two groups.

scholarly journals Effect of thyroid hormone on the myosin heavy chain isoforms in slow and fast muscles of the rat.

1999 ◽  
Vol 46 (3) ◽  
pp. 823-835 ◽  
Author(s):  
A Jakubiec-Puka ◽  
I Ciechomska ◽  
U Mackiewicz ◽  
J Langford ◽  
H Chomontowska
Keyword(s):  
Thyroid Hormone ◽  
Myosin Heavy Chain ◽  
Soleus Muscle ◽  
Heavy Chain ◽  
Myosin Heavy Chain Isoforms ◽  
Leg Muscles ◽  
Slow Twitch ◽  
Fast Twitch ◽  
Fast Muscles ◽  
Slow And Fast Muscles

The myosin heavy chain (MHC) was studied by biochemical methods in the slow-twitch (soleus) and two fast-twitch leg muscles of the triiodothyronine treated (hyperthyroid), thyroidectomized (hypothyroid) and euthyroid (control) rats. The changes in the contents of individual MHC isoforms(MHC-1, MHC-2A, MHC-2B and MHC-2X) were evaluated in relation to the muscle mass and the total MHC content. The MHC-1 content decreased in hyperthyreosis, while it increased in hypothyreosis in the soleus and in the fast muscles. The MHC-2A content increased in hyperthyreosis and it decreased in hypothyreosis in the soleus muscle. In the fast muscles hyperthyreosis did not affect the MHC-2A content, whereas hypothyreosis caused an increase in this MHC isoform content. The MHC-2X, present only in traces or undetected in the control soleus muscle, was synthesised in considerable amount in hyperthyreosis; in hypothyreosis the MHC-2X was not detected in the soleus. In the fast muscles the content of MHC-2X was not affected by any changes in the thyroid hormone level. The MHC-2B seemed to be not influenced by hyperthyreosis in the fast muscles, whereas the hypothyreosis caused a decrease of its content. In the soleus muscle the MHC-2B was not detected in any groups of rats. The results suggest that the amount of each of the four MHC isoforms expressed in the mature rat leg muscles is influenced by the thyroid hormone in a different way. The MHC-2A and the MHC-2X are differently regulated in the soleus and in the fast muscles; thyroid hormone seems to be necessary for expression of those isoforms in the soleus muscle.

Influence of training on blood flow to different skeletal muscle fiber types

1983 ◽  
Vol 55 (4) ◽  
pp. 1072-1078 ◽  
Author(s):  
B. G. Mackie ◽  
R. L. Terjung
Keyword(s):  
Blood Flow ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Plantaris Muscle ◽  
Blood Flows ◽  
Energy Demands ◽  
Flow Capacity ◽  
Slow Twitch ◽  
Fast Twitch

Blood flows to fast-twitch red (FTR), fast-twitch white (FTW), and slow-twitch red (STR) fiber sections of the gastrocnemius-soleus-plantaris muscle group of sedentary and trained rats were determined using radiolabeled microspheres during the 1st and 10th min of in situ contractions at frequencies ranging from 7.5 to 90 tetani/min. Treadmill training increased the cytochrome c content of both FTW (6.0 +/- 0.13 nmol/g to 12.2 +/- 0.27) and FTR (22.2 +/- 0.32 to 26.7 +/- 0.25) muscle. Loss of tension, evident at 15 tetani/min and above, was less (P less than 0.001) in trained animals. Although steady-state blood flows (10th min) to FTR and STR fibers were not altered by training, initial flows (1st min) to the trained FTR section were greater (P less than 0.025). Overall initial flows to both red fiber types were excessively high at the easier contraction conditions, but subsequently declined to values more reflective of the expected energy demands. This time-dependent relative hyperemia was not found in either sedentary or trained FTW muscle. However, training increased the maximal blood flow in the FTW sections [60 +/- 3.2 (n = 36) vs. 88 +/- 5.2 ml X min X 100 g-1 (n = 36)]. This 40-50% increase in FTW blood flow would produce only a modest 10% increase in blood flow to a whole mixed-fiber muscle, since the flow capacity of the FTW muscle is only one third to one fourth that of FTR muscle. This overall increase in blood flow, however, is similar to changes in VO2max found in trained rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Dystrophin-negative slow-twitch soleus muscles are not susceptible to eccentric contraction induced injury over the lifespan of the mdx mouse

2021 ◽  
Author(s):  
Leonit Kiriaev ◽  
Sindy Kueh ◽  
John W. Morley ◽  
Peter J. Houweling ◽  
Stephen Chan ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Soleus Muscle ◽  
Laser Scanning ◽  
Contractile Function ◽  
Eccentric Contraction ◽  
Laser Scanning Confocal Microscopy ◽  
Mdx Mouse ◽  
Scanning Confocal Microscopy ◽  
Slow Twitch ◽  
Fast Twitch

Duchenne muscular dystrophy (DMD) is the second most common fatal genetic disease in humans and is characterized by the absence of a functional copy of the protein dystrophin from skeletal muscle. In dystrophin-negative humans and rodents, regenerated skeletal muscle fibers show abnormal branching. The number of fibers with branches and the complexity of branching increases with each cycle of degeneration/regeneration. Previously, using the mdx mouse model of DMD, we have proposed that once the number and complexity of branched fibers present in dystrophic fast-twitch EDL muscle surpasses a stable level, we term "tipping point" the branches, in and of themselves, mechanically weaken the muscle by rupturing when subjected to high forces during eccentric contractions. Here we use the slow-twitch soleus muscle from the dystrophic mdx mouse to study pre-diseased "peri-ambulatory" dystrophic at 2-3 weeks, the peak regenerative "adult" phase at 6-9 weeks and "old" at 58-112 weeks. Using isolated mdx soleus muscles we examined contractile function and response to eccentric contraction correlated with amount and complexity of regenerated branched fibers. The intact muscle was enzymatically dispersed into individual fibers in order to count fiber branching and some muscles were optically cleared to allow laser scanning confocal microscopy. We demonstrate throughout the lifespan of the mdx mouse dystrophic slow-twitch soleus muscle is no more susceptible to eccentric contraction induced injury than age matched littermate controls and that this is correlated with a reduction in the number and complexity of branched fibers compared to fast-twitch dystrophic EDL muscles.

Absence of staircase following disuse in rat gastrocnemius muscle

1988 ◽  
Vol 66 (6) ◽  
pp. 707-713 ◽  
Author(s):  
Brian R. MacIntosh ◽  
Marie-Cristine Roberge ◽  
Phillip F. Gardiner
Keyword(s):  
Skeletal Muscles ◽  
Time Course ◽  
Gastrocnemius Muscle ◽  
Repetitive Stimulation ◽  
Muscle Weight ◽  
Twitch Contraction ◽  
Fast Twitch ◽  
Pulse Stimulation ◽  
Stimulation Of

Repetitive stimulation of mammalian fast-twitch skeletal muscles will normally result in a positive staircase response. This phenomenon was investigated in the rat gastrocnemius muscle following a 2-week period of tetrodotoxin-induced disuse. Muscle inactivity was imposed by superfusing tetrodotoxin in saline over the left sciatic nerve via an implanted osmotic pump. In situ isometric contractile responses to double pulse stimulation and repetitive stimulation at 10 Hz were determined the day after removal of the pump. Two weeks of disuse resulted in 40% muscle weight loss. A twitch contraction gave the same force when expressed per gram of wet muscle weight in control muscles, 317 ± 24.6 [Formula: see text] g/g, as compared with tetrodotoxin-treated muscles, 328 ± 24.2 g/g. Both contraction time and half-relaxation time were prolonged following treatment with tetrodotoxin. Repetitive stimulation at 10 Hz resulted in a positive staircase response in the control muscles, but not in muscles of the tetrodotoxin-treated rats. The observed changes in the time course of the twitch contraction with repetitive stimulation following tetrodotoxin-induced disuse are consistent with alterations in sarcoplasmic reticulum handling of calcium. It is not certain if there is a change following disuse in the mechanism normally associated with staircase or if this mechanism is merely opposed by an early fatigue.

Reflex responses of human soleus muscle to small perturbations

1976 ◽  
Vol 39 (5) ◽  
pp. 1105-1116 ◽  
Author(s):  
R. B. Stein ◽  
P. Bawa
Keyword(s):  
Soleus Muscle ◽  
Time Course ◽  
Human Subjects ◽  
Voluntary Contraction ◽  
M Wave ◽  
Force Fluctuations ◽  
Twitch Contraction ◽  
Small Branch ◽  
Normal Human ◽  
Damped Oscillation

1. A small branch of the nerve to soleus muscle in normal human subjects was stimulated intramuscularly with a needle electrode while the subjects were maintaining a steady voluntary contraction. The EMG and force fluctuations produced by these stimuli were recorded and averaged. 2. In addition to the M-wave produced directly by stimulating motoneurons and the resultant twitch contraction, one or more EMG waves were seen with a latency greater than 100 ms. These later waves produced further contractions, and when there were several later waves, the EMG and force fluctuations appeared as a damped oscillation with a frequency between 5.5 and 8 Hz. 3. By varying the angle of the ankle and hence the time course of the twitch contraction, the timing of the latter waves was shown to be closely related to the contraction time. Thus, the later waves appeared to be produced reflexly by the tension fluctuations, rather than directly by the stimulus. 4. The frequency response function between the tension fluctuations and the reflux EMG responses was computed. The gain agreed with that of primary muscle spindle afferents, but the phase data showed extra lags consistent with a time delay which was too long to be spinal in origin. This reflex probably involves supraspinal centers.

Separate turnover of cytochrome c and myoglobin in the red types of skeletal muscle

1981 ◽  
Vol 241 (3) ◽  
pp. C140-C144 ◽  
Author(s):  
R. C. Hickson ◽  
M. A. Rosenkoetter
Keyword(s):  
Skeletal Muscle ◽  
Cytochrome C ◽  
Time Course ◽  
Base Line ◽  
Turnover Rates ◽  
Fast Red ◽  
Slow Twitch ◽  
Exercise Endurance ◽  
Rate Of Decline ◽  
Fast Twitch

The purpose of this investigation was to determine whether cytochrome c and myoglobin have similar turnover rates in the three types of skeletal muscles. Exercise (endurance training) was used as an inducing stimulus to increase their concentrations. The half-lives (t 1/2) were subsequently estimated from the time course of return to base-line levels after cessation of exercise. When exercise was stopped, cytochrome c concentration returned rapidly to control levels; the lengths of t 1/2 were approximately 8 days in fast-twitch red, 5 days in slow-twitch red, and 9 days in mixed muscles. These findings confirm previous results of cytochrome c turnover. The concentration of myoglobin decreased at a slower rate than that observed for cytochrome c during detraining in fast-red slow-red, and plantaris muscles, and did not return to sedentary control levels throughout the 50-day detraining period. Myoglobin concentration in fast-twitch white muscle did not increase with the training. These results provide evidence that the degradation rate of myoglobin differs from that of cytochrome c in the red types of skeletal muscle. These elevated myoglobin levels may, in part, provide one explanation for the slow rate of decline in aerobic power that has been observed when individuals stop exercising.

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