Contractile properties of old rat muscles: effect of increased use

1989 ◽  
Vol 67 (4) ◽  
pp. 1401-1408 ◽  
Author(s):  
H. Klitgaard ◽  
R. Marc ◽  
A. Brunet ◽  
H. Vandewalle ◽  
H. Monod
Keyword(s):  
Skeletal Muscle ◽  
Strength Training ◽  
Weight Ratio ◽  
Contractile Properties ◽  
Male Rats ◽  
Strongly Correlated ◽  
Plantaris Muscle ◽  
Muscle Weight ◽  
Peak Tension ◽  
Time To Peak

To examine how different kinds of activity affect the composition and contractile properties of aging skeletal muscle, old male rats were strength and swim trained. The mass of weights lifted during the strength training increased by 85 +/- 9% (P less than 0.05), which was accompanied by an increase by 32 +/- 5% (P less than 0.05) of the estimated force developed. The wet muscle weight of the soleus and the plantaris decreased significantly with age. The phenomenon was counteracted but not neutralized by the strength training. Twitch and tetanic tension also decreased significantly with age in both the soleus and plantaris muscle. This was avoided by the strength training. This training also significantly decreased time to peak tension and half-relaxation time of both muscles. The swim training increased the heart-to-body weight ratio by 21 +/- 5% (P less than 0.05) and the endurance of the soleus muscle. Time to peak tension and triosephosphate dehydrogenase activity of the plantaris muscle were strongly correlated (P less than 0.001) with myosin adenosinetriphosphatase activity. The results show that the composition and contractile properties of old skeletal muscle are considerably affected by strength training repeated during a substantial period of old age, whereas swim training only affects the endurance of the skeletal muscle.

scholarly journals Hypertrophy of Rat Skeletal Muscle Is Associated with Increased SIRT1/Akt/mTOR/S6 and Suppressed Sestrin2/SIRT3/FOXO1 Levels

2021 ◽  
Vol 22 (14) ◽  
pp. 7588
Author(s):  
Zoltan Gombos ◽  
Erika Koltai ◽  
Ferenc Torma ◽  
Peter Bakonyi ◽  
Attila Kolonics ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Hypertrophy ◽  
Male Rats ◽  
Cellular Interactions ◽  
Molecular Signaling ◽  
Protein Breakdown ◽  
Rat Skeletal Muscle ◽  
Plantaris Muscle ◽  
Skeletal Muscle Hypertrophy ◽  
Intensive Investigation

Despite the intensive investigation of the molecular mechanism of skeletal muscle hypertrophy, the underlying signaling processes are not completely understood. Therefore, we used an overload model, in which the main synergist muscles (gastrocnemius, soleus) of the plantaris muscle were surgically removed, to cause a significant overload in the remaining plantaris muscle of 8-month-old Wistar male rats. SIRT1-associated pro-anabolic, pro-catabolic molecular signaling pathways, NAD and H2S levels of this overload-induced hypertrophy were studied. Fourteen days of overload resulted in a significant 43% (p < 0.01) increase in the mass of plantaris muscle compared to sham operated animals. Cystathionine-β-synthase (CBS) activities and bioavailable H2S levels were not modified by overload. On the other hand, overload-induced hypertrophy of skeletal muscle was associated with increased SIRT1 (p < 0.01), Akt (p < 0.01), mTOR, S6 (p < 0.01) and suppressed sestrin 2 levels (p < 0.01), which are mostly responsible for anabolic signaling. Decreased FOXO1 and SIRT3 signaling (p < 0.01) suggest downregulation of protein breakdown and mitophagy. Decreased levels of NAD+, sestrin2, OGG1 (p < 0.01) indicate that the redox milieu of skeletal muscle after 14 days of overloading is reduced. The present investigation revealed novel cellular interactions that regulate anabolic and catabolic processes in the hypertrophy of skeletal muscle.

Properties of immobilized guinea pig hindlimb muscles

1976 ◽  
Vol 231 (5) ◽  
pp. 1520-1526 ◽  
Author(s):  
A Maier ◽  
JL Crockett ◽  
DR Simpson ◽  
IV Saubert CW ◽  
VR Edgerton
Keyword(s):  
Guinea Pig ◽  
Chloral Hydrate ◽  
Myofibrillar Protein ◽  
Contractile Properties ◽  
Specific Factor ◽  
Normal Muscle ◽  
Muscle Weight ◽  
Time To Peak ◽  
Hindlimb Muscles ◽  
Tetanic Tension

Guinea pig hindlimbs were unilaterally immobilized at resting length to evaluate histochemical, biochemical, and contractile properties of immobilized muscle. Contralateral limbs remained unrestrained. Four weeks later contractile properties were measured under chloral hydrate anesthesia. Average time-to-peak tension of the immobilized soleus was 30% less, whereas that of the gastrocnemius was not significantly changed relative to contralateral muscles. Immobilized soleus muscles acquired as much as 25% fibers with high alkaline myofibrillar adenosine triphosphatase activity; these fibers do not occur in the normal muscle. Neither the immobilized soleus nor gastrocnemius fatigued more quickly than their contralateral counterparts. In the immobilized gastrocnemius myofibrillar protein (mg/g muscle) decreased to 76% and maximum tetanic tension to 70% of contralateral values. However, tetanic tension per gram wet muscle weight or 100 mg myofibrillar protein was significantly greater in the immobilized gastrocnemius. No specific factor responsible for the increased tetanic tension could be identified.

Contractile properties and myosin expression in rats born and reared in hypergravity

2002 ◽  
Vol 282 (6) ◽  
pp. R1687-R1695 ◽  
Author(s):  
F. Picquet ◽  
V. Bouet ◽  
M. H. Canu ◽  
L. Stevens ◽  
Y. Mounier ◽  
...  
Keyword(s):  
Contractile Properties ◽  
Fiber Types ◽  
Hybrid Fiber ◽  
Plantaris Muscle ◽  
Muscle Weight ◽  
Cross Sectional ◽  
Mhc I ◽  
Contractile Parameters ◽  
Wet Weight ◽  
Muscle Types

The effects of hypergravity (HG) on soleus and plantaris muscles were studied in Long Evans rats aged 100 days, born and reared in 2- g conditions (HG group). The morphological and contractile properties and the myosin heavy chain (MHC) content were examined in whole muscles and compared with terrestrial control (Cont) age-paired rats. The growth of HG rats was slowed compared with Cont rats. A decrease in absolute muscle weight was observed. An increase in fiber cross-sectional area/muscle wet weight was demonstrated, associated with an increase in relative maximal tension. The soleus muscle changed into a slower type both in contractile parameters and in MHC content, since HG soleus contained only the MHC I isoform. The HG plantaris muscle presented a faster contractile behavior. Moreover, the diversity of hybrid fiber types expressing multiple MHC isoforms (including MHC IIB and MHC IIX isoforms) was increased in plantaris muscle after HG. Thus the HG environment appears as an important inductor of muscular plasticity both in slow and fast muscle types.

Exercise training improves lusitropy by isoproterenol in papillary muscles from aged rats

1996 ◽  
Vol 81 (4) ◽  
pp. 1488-1494 ◽  
Author(s):  
George E. Taffet ◽  
Lloyd A. Michael ◽  
Charlotte A. Tate
Keyword(s):  
Exercise Training ◽  
Maximum Rate ◽  
Left Ventricular ◽  
Male Rats ◽  
Papillary Muscles ◽  
Inotropic Response ◽  
Aged Rats ◽  
Adrenergic Stimulation ◽  
Peak Tension ◽  
Time To Peak

Taffet, George E., Lloyd A. Michael, and Charlotte A. Tate.Exercise training improves lusitropy by isoproterenol in papillary muscles from aged rats. J. Appl. Physiol. 81(4): 1488–1494, 1996.—Aging is associated with a decreased cardiac responsiveness to β-adrenergic stimulation. We examined the effect of endurance exercise training of old Fischer 344 male rats on β-adrenergic stimulation of the function of isolated left ventricular papillary muscle. Three groups were examined: sedentary mature (SM; 12-mo old), sedentary old (SO; 23–24 mo old), and exercised old (EO; 23–24 mo old) that were treadmill trained for 4–8 wk. The isometric contractile properties were studied at 0.2 Hz and 0.75 mM calcium. Without β-adrenergic stimulation, there were no group differences for peak tension, maximum rate of tension development (+dP/d t), or maximum rate of tension dissipation (−dP/d t). The time to peak tension was longer ( P < 0.05) for both EO and SO than for SM rats. Half relaxation time (RT1/2) was prolonged ( P < 0.05) for SO compared with SM and EO (which did not differ). The three groups did not differ in the β-adrenergic stimulation by isoproterenol of peak tension, −dP/d t, time to peak tension, or contraction duration. The inotropic response (+dP/d t) of SM was greater ( P < 0.05) than that in SO or EO rats (which did not differ); however, the lusitropic response (RT1/2) was lesser ( P < 0.05) in SO than in SM or EO rats (which did not differ). Thus exercise training of old rats improved the lusitropic response to isoproterenol without altering the age-associated impairment in inotropic response.

scholarly journals Excitability and contractility of skeletal muscle engineered from primary cultures and cell lines

2001 ◽  
Vol 280 (2) ◽  
pp. C288-C295 ◽  
Author(s):  
Robert G. Dennis ◽  
Paul E. Kosnik ◽  
Mark E. Gilbert ◽  
John A. Faulkner
Keyword(s):  
Skeletal Muscle ◽  
Relaxation Time ◽  
Cell Lines ◽  
Isometric Force ◽  
Cross Sectional Area ◽  
Specific Force ◽  
Sectional Area ◽  
Cross Sectional ◽  
Peak Tension ◽  
Time To Peak

The purpose of this study was to compare the excitability and contractility of three-dimensional skeletal muscle constructs, termed myooids, engineered from C2C12 myoblast and 10T½ fibroblast cell lines, primary muscle cultures from adult C3H mice, and neonatal and adult Sprague-Dawley rats. Myooids were 12 mm long, with diameters of 0.1–1 mm, were excitable by transverse electrical stimulation, and contracted to produce force. After ∼30 days in culture, myooid cross-sectional area, rheobase, chronaxie, resting baseline force, twitch force, time to peak tension, one-half relaxation time, and peak isometric force were measured. Specific force was calculated by dividing peak isometric force by cross-sectional area. The specific force generated by the myooids was 2–8% of that generated by skeletal muscles of control adult rodents. Myooids engineered from C2C12-10T½ cells exhibited greater rheobase, time to peak tension, and one-half relaxation time than myooids engineered from adult rodent cultures, and myooids from C2C12-10T½ and neonatal rat cells had greater resting baseline forces than myooids from adult rodent cultures.

scholarly journals Effect of pulmonary TNF-α overexpression on mouse isolated skeletal muscle function

2011 ◽  
Vol 301 (4) ◽  
pp. R1025-R1031 ◽  
Author(s):  
Li Zuo ◽  
Leonardo Nogueira ◽  
Michael C. Hogan
Keyword(s):  
Skeletal Muscle ◽  
Muscle Function ◽  
Weight Ratio ◽  
The Body ◽  
Chronic Obstructive ◽  
Skeletal Muscle Function ◽  
Muscle Weight ◽  
Peak Rate ◽  
Tnf Α

TNF-α is a proinflammatory cytokine that is involved in numerous pathological processes including chronic obstructive pulmonary disease (COPD). In the present study, we used a transgenic mouse model that overexpresses TNF-α in the lung (Tg+) to test the hypothesis that chronic exposure to TNF-α (as seen in COPD) reduces skeletal muscle force production and fatigue resistance, particularly under low Po2 conditions. At 7–12 mo, body and muscle weight of both extensor digitorum longus (EDL) and soleus were significantly smaller in Tg+ compared with littermate wild-type (WT) mice; however, the body-to-muscle weight ratio was not different between groups. EDL and soleus muscles were subjected to in vitro fatiguing contractile periods under high (∼550 Torr) and low Po2 (∼40 Torr). Although all muscles were less fatigue-resistant during low Po2 compared with high Po2, only the soleus fatigued more rapidly in Tg+ mice (∼12%) compared with WT at high Po2. The maximal tension of EDL was equally reduced in Tg+ mice (28–34% decrease from WT under both Po2 conditions); but for soleus this parameter was smaller only under low Po2 in Tg+ mice (∼31% decrease from WT). The peak rate of relaxation and the peak rate of contraction were both significantly reduced in Tg+ EDL muscles compared with WT EDL under low Po2 conditions, but not in soleus. These results demonstrate that TNF-α upregulation in the lung impairs peripheral skeletal muscle function but affects fast- and slow-twitch muscles differentially at high and low Po2.

Influence of overload on recovery of rat plantaris from partial denervation

1989 ◽  
Vol 66 (2) ◽  
pp. 732-740 ◽  
Author(s):  
R. N. Michel ◽  
P. F. Gardiner
Keyword(s):  
Muscle Fibers ◽  
Motor Units ◽  
Surgical Removal ◽  
Plantaris Muscle ◽  
Cross Sectional ◽  
Peak Tension ◽  
Time To Peak ◽  
Partial Denervation ◽  
Whole Muscle ◽  
Tetanic Tension

A functional index of neural adaptability is the capacity of motoneurons to extend and establish supernumerary connections with neighboring denervated muscle fibers. The purpose of this study was to guage this response in rat plantaris muscles subjected to increased levels of activity resulting from the surgical removal of the synergistic gastrocnemius and soleus muscles. Thirty-seven days of overload increased plantaris absolute (69%) and relative (82%) weight, whole muscle (35%) and individual fiber (37%) mean cross-sectional area, half-relaxation time (1/2RT; 25%), and maximum tetanic tension (P0; 21%). In a separate group of animals that had undergone 30 days of overload, three-quarters of the plantaris muscle fibers were denervated by sectioning radicular nerve L4. At 7 days postlesion, contractile responses were obtained from sprouting motor units remaining in radicular nerve L5, and the results compared to a nonoverloaded group that had undergone this same procedure. Twitch time to peak tension and 1/2RT were prolonged in normal partially denervated (PD) and overloaded partially denervated (OPD) muscles, and this response was significantly greater in the overloaded muscles. Both PD and OPD muscles increased twitch tension (38%) and peak tension developed at 25 Hz (34%) to a similar extent, during recovery from partial denervation. These increases, attributable to sprouting of L5 motor axon collaterals, were matched in PD muscles with a corresponding increase in P0, a response which did not occur in OPD muscles. Additionally, a more extensive decrease in P0 occurred as a result of partial denervation in OPD muscles compared with whole muscle P0 of nondenervated muscle (L4 plus L5 stimulation).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of castration and androgen treatment on androgen-receptor levels in rat skeletal muscles

1999 ◽  
Vol 87 (6) ◽  
pp. 2016-2019 ◽  
Author(s):  
Jose Antonio ◽  
Jean D. Wilson ◽  
Fredrick W. George
Keyword(s):  
Skeletal Muscle ◽  
Androgen Receptor ◽  
Muscle Mass ◽  
Skeletal Muscles ◽  
Skeletal Muscle Mass ◽  
Levator Ani ◽  
Male Rats ◽  
Levator Ani Muscle ◽  
Plantaris Muscle ◽  
Androgen Treatment

The effects of castration and dihydrotestosterone (DHT) treatment on levels of skeletal muscle androgen receptor (AR) were examined in three groups of adult male rats: 1) intact normal rats, 2) rats castrated at 16 wk of age, and 3) rats castrated at 16 wk of age and given DHT for 1 wk starting at week 17. All animals were killed at 18 wk of age. Castration caused a decrease ( P< 0.05) in the weights of the levator ani and bulbocavernosus muscles. The administration of DHT to the castrated rats increased ( P < 0.05) the weights of the levator ani and bulbocavernosus muscles. Castration caused a significant downregulation of AR levels in the bulbocavernosus ( P< 0.05) but had no significant effect on AR levels in the levator ani muscle. DHT administration to the castrated group upregulated AR levels in the bulbocavernosus and levator ani muscles. The plantaris muscle did not significantly ( P > 0.05) change for any of the treatments. These findings suggest that the effects of castration and androgen replacement differentially affect skeletal muscle mass and AR levels.

Reactive oxygen in skeletal muscle. III. Contractility of unfatigued muscle

1993 ◽  
Vol 75 (3) ◽  
pp. 1081-1087 ◽  
Author(s):  
M. B. Reid ◽  
F. A. Khawli ◽  
M. R. Moody
Keyword(s):  
Skeletal Muscle ◽  
Hydrogen Peroxide ◽  
Relaxation Time ◽  
Contractile Function ◽  
Reactive Oxygen ◽  
Reactive Oxygen Intermediates ◽  
Oxygen Intermediates ◽  
Peak Tension ◽  
Time To Peak ◽  
Dose Dependent

This study tested the hypothesis that reactive oxygen intermediates present in unfatigued skeletal muscle act to enhance contractile function. Fiber bundles from rat diaphragm were incubated with exogenous catalase (an antioxidant enzyme that dehydrates hydrogen peroxide to molecular oxygen and water) to decrease the tissue concentration of reactive oxygen intermediates. Catalase (10(3) U/ml) significantly decreased twitch characteristics (time to peak tension, half-relaxation time, peak force, and twitch-to-tetanus force ratio), thereby shifting the force-frequency relationship to the right. Catalase effects were dose dependent. Concentrations of 1 to 10(5) U/ml progressively depressed submaximal (30-Hz) tetanic stress, whereas concentrations > 10(5) U/ml were toxic, inhibiting maximal (200-Hz) tetanic stress (P < 0.0001). Exogenous hydrogen peroxide (10(-4) to 10(-2)M) increased peak twitch stress (P < 0.03) and lengthened both time to peak tension (P < 0.02) and half-relaxation time (P < 0.02). Selective removal of superoxide anion radicals with the use of superoxide dismutase produced dose-dependent contractile inhibition similar to that produced by catalase. We conclude that the reactive oxygen intermediates present in unfatigued skeletal muscle have a positive effect on excitation-contraction coupling and are obligatory for optimal contractile function.

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