Effect of inactivity and passive stretch on protein turnover in phasic and postural rat muscles

1986 ◽  
Vol 61 (1) ◽  
pp. 173-179 ◽  
Author(s):  
P. Loughna ◽  
G. Goldspink ◽  
D. F. Goldspink
Keyword(s):  
Soleus Muscle ◽  
Muscle Length ◽  
Protein Breakdown ◽  
Fractional Rate ◽  
Hindlimb Muscles ◽  
Synthetic Rate ◽  
Suspension Model ◽  
Fast Twitch ◽  
Passive Stretch

A state of hypokinesia and hypodynamia has been induced in the hindlimb muscles of the rat (100 g) using a suspension model. The ensuing muscle atrophy was assessed by reference to muscles in fully mobile control animals, which were either fed ad libitum or fed the same lower food intake of the suspended animals. Over a total of 7 days of suspension the slow-twitch postural soleus muscle underwent a much greater atrophy than the fast-twitch phasic extensor digitorum longus. Changes with respect to the position of the suspended foot, and hence muscle length, necessitate caution in comparing the extent of the atrophy between different muscle types. After 3 days of inactivity the atrophy of the soleus muscle was explained by a 21% decrease in the fractional rate of synthesis (measured in vivo) and a 100% increase in the rate of protein breakdown. The reduction in the synthetic rate was associated with a net loss (23%) of RNA and hence muscle ribosomes. In contrast when this inactive soleus muscle was permanently stretched the RNA content (44%) and protein synthetic rate increased (59%) markedly above control values. Although protein breakdown remained elevated in this stretched muscle, the extent of the atrophy in response to hypokinesia and hypodynamia was greatly reduced.

scholarly journals Protein turnover measured in vivo and in vitro in muscles undergoing compensatory growth and subsequent denervation atrophy

1983 ◽  
Vol 210 (1) ◽  
pp. 89-98 ◽  
Author(s):  
D F Goldspink ◽  
P J Garlick ◽  
M A McNurlan
Keyword(s):  
Protein Synthesis ◽  
Protein Turnover ◽  
Compensatory Growth ◽  
Protein Breakdown ◽  
Synthetic Rate ◽  
Longus Muscle ◽  
Passive Stretch ◽  
Good Agreement

The rapid growth (1-6 days) of the functionally overloaded soleus muscle, in response to tenotomy of the synergist gastrocnemius, was found to correlate with increases in both the protein synthetic and degradative rates, the change in the former being greater than that of the latter. These conclusions were drawn from two different methods used to measure (in vivo and in vitro) the average rates of protein synthesis and protein breakdown in these soleus muscles. Although the basal rates of synthesis were higher when measured in vivo, and the degradative rates higher in isolated muscle preparations incubated in vitro, both methods gave good agreement concerning the changes in protein turnover induced by tenotomy of the gastrocnemius. The possible involvement of passive stretch in inducing this additional growth is discussed. As an antagonist to the soleus, growth of the extensor digitorum longus muscle was decreased under the same conditions, presumably because of less usage. At 3 days after the cutting of the sciatic nerve, the previously normal or overloaded soleus muscles underwent rapid atrophy. Although in both cases RNA and protein were lost, while protein synthesis decreased and protein breakdown increased, denervation induced larger changes within these parameters of the formerly overloaded muscle. The slowing of growth in the tenotomized gastrocnemius, and its subsequent rapid atrophy after additional denervation, were explained by large increases in protein breakdown, with little or no change in the synthetic rate.

Changes in protein turnover in rat uterus during pregnancy

1986 ◽  
Vol 250 (2) ◽  
pp. E114-E120 ◽  
Author(s):  
A. J. Morton ◽  
D. F. Goldspink
Keyword(s):  
Protein Synthesis ◽  
Protein Degradation ◽  
Protein Turnover ◽  
Cathepsin D ◽  
Cell Loss ◽  
Protein Breakdown ◽  
Rat Uterus ◽  
Fractional Rate ◽  
Uterine Growth

The adaptive growth and protein turnover of the rat uterus were studied during the 21 days of gestation and up to 3 days after parturition. Despite large increases (13-fold) in uterine size during gestation, the fractional rate of protein synthesis (measured in vivo) remained unchanged when compared with nonpregnant tissue values of 44 +/- 5%/day. However, decreases were found in the rate of protein breakdown after implantation (i.e., 75% on day 7 and 28% on day 11) and in the activity of cathepsin D (i.e., 33 and 85% on days 8 and 16 of gestation). Changes in the degradative processes would therefore appear to be primarily responsible for the massive uterine growth during pregnancy. In contrast to the uterus the fractional rates of synthesis in the placenta and fetus progressively decreased during gestation. After parturition the uterus rapidly returned to its normal size by a combination of cellular atrophy and cell loss. After 2 days, a complementary decrease in the fractional rate of synthesis (30%) and an increase in protein degradation (2-fold) explained the process of involution.

Akt signaling in skeletal muscle: regulation by exercise and passive stretch

2003 ◽  
Vol 285 (5) ◽  
pp. E1081-E1088 ◽  
Author(s):  
Kei Sakamoto ◽  
William G. Aschenbach ◽  
Michael F. Hirshman ◽  
Laurie J. Goodyear
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Glycogen Synthase ◽  
Contractile Activity ◽  
Akt Signaling ◽  
Fiber Types ◽  
Akt Activation ◽  
Fast Twitch ◽  
Passive Stretch

Akt/protein kinase B is a serine/threonine kinase that has emerged as a critical signaling component for mediating numerous cellular responses. Contractile activity has recently been demonstrated to stimulate Akt signaling in skeletal muscle. Whether physiological exercise in vivo activates Akt is controversial, and the initiating factors that result in the stimulation of Akt during contractile activity are unknown. In the current study, we demonstrate that treadmill running exercise of rats using two different protocols (intermediate high or high-intensity exhaustive exercise) significantly increases Akt activity and phosphorylation in skeletal muscle composed of various fiber types. To determine if Akt activation during contractile activity is triggered by mechanical forces applied to the skeletal muscle, isolated skeletal muscles were incubated and passively stretched. Passive stretch for 10 min significantly increased Akt activity (2-fold) in the fast-twitch extensor digitorum longus (EDL) muscle. However, stretch had no effect on Akt in the slow-twitch soleus muscle, although there was a robust phosphorylation of the stress-activated protein kinase p38. Similar to contraction, stretch-induced Akt activation in the EDL was fully inhibited in the presence of the phosphatidylinositol 3-kinase inhibitor wortmannin, whereas glycogen synthase kinase-3 (GSK3) phosphorylation was only partially inhibited. Stretch did not cause dephosphorylation of glycogen synthase on GSK3-targeted sites in the absence or presence of wortmannin. We conclude that physiological exercise in vivo activates Akt in multiple skeletal muscle fiber types and that mechanical tension may be a part of the mechanism by which contraction activates Akt in fast-twitch muscles.

scholarly journals Three-dimensional architecture of the whole human soleus muscle in vivo

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4610 ◽  
Author(s):  
Bart Bolsterlee ◽  
Taija Finni ◽  
Arkiev D’Souza ◽  
Junya Eguchi ◽  
Elizabeth C. Clarke ◽  
...  
Keyword(s):  
Soleus Muscle ◽  
Diffusion Tensor ◽  
Three Dimensional ◽  
Muscle Length ◽  
Fascicle Length ◽  
Cross Sectional ◽  
Quantitative Measurements ◽  
Muscle Fascicle ◽  
Total Muscle

Background Most data on the architecture of the human soleus muscle have been obtained from cadaveric dissection or two-dimensional ultrasound imaging. We present the first comprehensive, quantitative study on the three-dimensional anatomy of the human soleus muscle in vivo using diffusion tensor imaging (DTI) techniques. Methods We report three-dimensional fascicle lengths, pennation angles, fascicle curvatures, physiological cross-sectional areas and volumes in four compartments of the soleus at ankle joint angles of 69 ± 12° (plantarflexion, short muscle length; average ± SD across subjects) and 108 ± 7° (dorsiflexion, long muscle length) of six healthy young adults. Microdissection and three-dimensional digitisation on two cadaveric muscles corroborated the compartmentalised structure of the soleus, and confirmed the validity of DTI-based muscle fascicle reconstructions. Results The posterior compartments of the soleus comprised 80 ± 5% of the total muscle volume (356 ± 58 cm3). At the short muscle length, the average fascicle length, pennation angle and curvature was 37 ± 8 mm, 31 ± 3° and 17 ± 4 /m, respectively. We did not find differences in fascicle lengths between compartments. However, pennation angles were on average 12° larger (p < 0.01) in the posterior compartments than in the anterior compartments. For every centimetre that the muscle-tendon unit lengthened, fascicle lengths increased by 3.7 ± 0.8 mm, pennation angles decreased by −3.2 ± 0.9° and curvatures decreased by −2.7 ± 0.8 /m. Fascicles in the posterior compartments rotated almost twice as much as in the anterior compartments during passive lengthening. Discussion The homogeneity in fascicle lengths and inhomogeneity in pennation angles of the soleus may indicate a functionally different role for the anterior and posterior compartments. The data and techniques presented here demonstrate how DTI can be used to obtain detailed, quantitative measurements of the anatomy of complex skeletal muscles in living humans.

scholarly journals A comparison of methods for the measurement of protein turnover in vivo

1979 ◽  
Vol 184 (2) ◽  
pp. 473-476 ◽  
Author(s):  
M L MacDonald ◽  
S L Augustine ◽  
T L Burk ◽  
R W Swick
Keyword(s):  
Amino Acids ◽  
Steady State ◽  
Protein Turnover ◽  
Muscle Protein ◽  
Comparison Of Methods ◽  
Ornithine Aminotransferase ◽  
Protein Breakdown ◽  
Muscle Protein Breakdown ◽  
Fractional Rate

Steady-state rates of turnover of two single proteins were measured in vivo by two independent methods. The fractional rate of synthesis of liver ornithine aminotransferase, measured by a continuous infusion of L-[2,6-3H]tyrosine, was 0.42 day-1, whereas in the same animals the fractional rate of degradation measured by loss of radioactivity from amino acids labelled via [14C]bicarbonate was 0.40 day-1. The agreement between methods confirms the reliability of each method for the study of hepatic protein turnover. In contrast, [14C]bicarbonate-labelled amino acids are extensively reutilized in muscle, and are therefore unsuitable for measuring rates of muscle protein breakdown.

Sarcomere length and capillary curvature of rat hindlimb muscles in vivo

1995 ◽  
Vol 78 (6) ◽  
pp. 2047-2051 ◽  
Author(s):  
M. A. Ledvina ◽  
S. S. Segal
Keyword(s):  
Skeletal Muscle ◽  
Sarcomere Length ◽  
Muscle Length ◽  
Physiological Saline ◽  
Mammalian Skeletal Muscle ◽  
Sprague Dawley ◽  
Hindlimb Muscles ◽  
Physiological Saline Solution ◽  
The Right

Mammalian skeletal muscle fibers have been reported to develop maximum force at a sarcomere length (Ls) of approximately 2.5 microns. However, the functional range of muscle length (Lm) and Ls encountered by skeletal muscle in vivo is not well defined. Changes in Ls markedly influence capillary geometry, but this effect has been shown only in fixed preparations. The purpose of this study was to evaluate the influence of limb position on Lm, Ls, and capillary geometry in living undisturbed hindlimb muscles. We tested the hypothesis that maximal excursion of the foot would have similar effects on Ls and capillary geometry of antagonistic soleus (Sol) and extensor digitorum longus (EDL) muscles in vivo. Female Sprague-Dawley rats (n = 9; 243 +/- 3 g) were anesthetized (pentobarbital sodium; 35 mg/kg). The right Sol and EDL muscles were exposed and irrigated with physiological saline solution (34 degrees C; pH 7.4). Sarcomeres and capillaries were observed with video microscopy (total magnification x 1,900; spatial resolution < 1 micron); sarcomeres were labeled with a fluorescent dye [4-(4-diethylaminostyryl)-N-methylpyridinium iodide]. As foot angle increased from 30 degrees (maximal dorsiflexion) to 170 degrees (maximal plantarflexion), Lm and Ls increased for EDL muscles (27.51 +/- 0.42 to 30.97 +/- 0.25 mm and 2.33 +/- 0.01 to 3.09 +/- 0.05 microns, respectively; P < 0.05) and decreased for Sol muscles (26.09 +/- 0.38 to 20.27 +/- 0.34 mm and 3.17 +/- 0.03 to 2.22 +/- 0.04 microns, respectively; P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Akt kinases and 2-deoxyglucose uptake in rat skeletal muscles in vivo: study with insulin and exercise

1999 ◽  
Vol 276 (1) ◽  
pp. R277-R282 ◽  
Author(s):  
Jiri Turinsky ◽  
Alice Damrau-Abney
Keyword(s):  
Glucose Uptake ◽  
Soleus Muscle ◽  
Insulin Injection ◽  
Plantaris Muscle ◽  
Hindlimb Muscles ◽  
Slow Twitch Muscle ◽  
Fast Twitch Muscle ◽  
Exercise Induced ◽  
Calf Muscles

Activities of Akt1, Akt2, and Akt3 kinases and glucose uptake in hindlimb muscles of the rat in vivo were investigated. The rats were studied either after intravenous injection of 0.1 U of insulin or during exercise induced by stimulating calf muscles electrically at 1 contraction/s. Akt kinases were immunoprecipitated from supernatants of muscle homogenates. Glucose uptake by muscles in vivo was assessed by cellular accumulation of 2-deoxy-d-[1,2-3H(N)]glucose. Administration of insulin resulted in rapid activation of Akt1 kinase, with peak activity observed 5 min after insulin injection. Soleus muscle, a slow-twitch muscle, and plantaris muscle, a fast-twitch muscle, differed in their content of Akt1 kinase and in their response to insulin. Soleus muscle exhibited a 105% higher abundance of Akt1 kinase, a 101% higher insulin-stimulated activity of Akt1 kinase, and 83% higher insulin-stimulated 2-deoxyglucose uptake compared with plantaris muscle. Additionally, insulin administration increased the activities of Akt1, Akt2, and Akt3 kinases in calf muscles and caused a sevenfold augmentation in 2-deoxyglucose uptake by these muscles. In contrast, the exercised calf muscles exhibited an increase in Akt1 kinase activity at 5, 15, and 25 min of exercise but no change in activities of Akt2 and Akt3 isoforms, and the 2-deoxyglucose uptake by calf muscles exercised for 25 min was 11-fold higher compared with muscles of resting rats. The data demonstrate that 1) there is a close, direct correlation between the magnitude of insulin-stimulated activity of Akt1 kinase and the level of glucose uptake in muscles with different fiber populations, 2) insulin activates three isoforms of Akt kinase in skeletal muscle, and 3) exercise in vivo is associated with activation of Akt1 but not Akt2 and Akt3 kinases in contracting muscles.

scholarly journals Blood flow and glucose uptake in denervated, insulin-resistant muscles

1998 ◽  
Vol 274 (2) ◽  
pp. R311-R317 ◽  
Author(s):  
Jiri Turinsky ◽  
Alice Damrau-Abney ◽  
Daniel J. Loegering
Keyword(s):  
Insulin Resistance ◽  
Blood Flow ◽  
Soleus Muscle ◽  
Internal Control ◽  
Muscle Blood Flow ◽  
Insulin Resistant ◽  
Denervated Muscles ◽  
Gastrocnemius Muscles ◽  
Fast Twitch

To investigate whether changes in blood flow contribute to the insulin resistance in denervated muscles, basal and insulin-stimulated 2-deoxy-d-glucose (2-DG) uptake in vivo and blood flow were measured in soleus (slow twitch), plantaris (fast twitch), and gastrocnemius (fast twitch) muscles at 1 and 3 days after a right hindlimb denervation in the rat. Muscles of the contralateral sham hindlimb served as an internal control. Sham plantaris and gastrocnemius muscles showed 32 and 60% lower basal 2-DG uptake, 46 and 66% lower insulin-stimulated 2-DG uptake, and 79 and 81% lower blood flow, respectively, compared with sham soleus muscle. At 1 day after denervation, soleus, plantaris, and gastrocnemius muscles exhibited an 80, 64, and 42% decrease in insulin-stimulated 2-DG uptake, respectively, in the presence of 63, 323, and 304% higher blood flow, respectively. At 3 days after denervation, soleus muscle showed a 60% decrease in basal 2-DG uptake, complete unresponsiveness to insulin, and an 86% decrease in blood flow. In contrast, the denervated plantaris and gastrocnemius muscles exhibited a 262 and 105% increase in basal 2-DG uptake, respectively, no change in insulin-stimulated 2-DG uptake, and no change in blood flow compared with corresponding contralateral sham muscles. The results demonstrate that muscle blood flow is influenced by muscle fiber population and time after denervation and that changes in blood flow do not contribute to the insulin resistance in the denervated muscles.

Daily in vivo neuromuscular stimulation effects on immobilized rat hindlimb muscles

1982 ◽  
Vol 53 (4) ◽  
pp. 960-966 ◽  
Author(s):  
P. F. Gardiner ◽  
M. A. Lapointe
Keyword(s):  
Relaxation Times ◽  
Plaster Cast ◽  
Daily Regimen ◽  
Cross Sectional ◽  
Time To Peak ◽  
Hindlimb Muscles ◽  
Twitch Characteristics ◽  
Gastrocnemius Muscles ◽  
Fast Twitch

The purpose of the investigation was to determine the effects of a daily regimen of near-maximal contractions, produced via in vivo electrical stimulation of peripheral nerve, on functional and histochemical properties of rat hindlimb muscles immobilized for 28 days in a plaster cast. Rats had knee and ankle joints of one hindlimb immobilized; then while anesthetized, half of the group was subjected to a daily regimen of 480 semifused tetanic contractions (50 Hz) via fine-wire electrodes chronically implanted around the sciatic nerve. Immobilization caused significant decreases in soleus and gastrocnemius muscle weights, fiber cross-sectional areas, and twitch and tetanic strength measured in situ. In addition, immobilized soleus muscles had faster time to peak tension (TPT) and higher proportions of fast-twitch fibers, whereas immobilized gastrocnemius muscles demonstrated faster half-relaxation times (RT1/2) and total twitch durations (TPT plus RT1/2). The only significant effects of the imposed contractions were evident in the gastrocnemius in which stimulation prevented the shortening of RT1/2 and total twitch duration and resulted in significantly higher relative tensions at 50 Hz and higher fatigue resistance. Muscle activity of this type imposed on immobilized muscle is ineffective in attenuating atrophy but can, in fast muscle such as gastrocnemius, prevent changes in twitch characteristics resulting from immobilization, as well as augment contractile responses during semifused and fatiguing contractions.

Relative metabolic utilization of in situ rabbit soleus muscle: thermistor-based measurements and model

2000 ◽  
Vol 203 (23) ◽  
pp. 3667-3674
Author(s):  
K.J. Gustafson ◽  
G.D. Egrie ◽  
S.H. Reichenbach
Keyword(s):  
Skeletal Muscle ◽  
Soleus Muscle ◽  
Muscle Length ◽  
Multiple Linear Regression Model ◽  
Active Tension ◽  
Contraction Duration ◽  
Continuous Power

Electrically conditioned skeletal muscle can provide the continuous power source for cardiac assistance devices. Optimization of the available sustained power from in vivo skeletal muscle requires knowledge of its metabolic utilization and constraints. A thermistor-based technique has been developed to measure temperature changes and to provide a relative estimate for metabolic utilization of in situ rabbit soleus muscle. The relative thermistor response, active tension and muscle displacement were measured during cyclic isometric and isotonic contractions across a range of muscle tensions and contraction durations. The thermistor response demonstrated linear relationships versus both contraction duration at a fixed muscle length and active tension at a fixed contraction duration (r(2)=0.90+/−0.14 and 0.70+/−0.21, respectively; means +/− s.d.). A multiple linear regression model was developed to predict normalized thermistor response, DeltaT, across a range of conditions. Significant model variables were identified using a backward stepwise regression procedure. The relationships for the in situ muscles were qualitatively similar to those reported for mammalian in vitro muscle fiber preparations. The model had the form DeltaT=C+at(c)F+bW, where the constant C, and coefficients for the contraction duration t(c) (ms), normalized active tension F and normalized net work W were C=−1.00 (P&lt;0.001), a=5.97 (P&lt;0.001) and b=2.12 (P&lt;0.001).

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