Time course of soleus muscle myosin expression during hindlimb suspension and recovery

1987 ◽  
Vol 63 (1) ◽  
pp. 130-137 ◽  
Author(s):  
D. B. Thomason ◽  
R. E. Herrick ◽  
D. Surdyka ◽  
K. M. Baldwin
Keyword(s):  
Protein Expression ◽  
Soleus Muscle ◽  
Time Course ◽  
Weight Bearing ◽  
Relative Proportion ◽  
Contractile Protein ◽  
Myosin Isoforms ◽  
Hindlimb Unweighting ◽  
Loss Of Weight ◽  
Myofibril Protein

This study examined the time course of adult rodent soleus muscle myofibril and myosin isoform protein expression after 4, 8, 16, 28, and 56 days of hindlimb unweighting by tail suspension (S). The time course of soleus muscle recovery (R) was also examined after 28 days of hindlimb unweighting with an additional 4, 8, 16, and 28 days of unrestricted cage activity. During suspension, soleus muscle myofibril protein rapidly decreased from 34.3 +/- 3.1 (1.96SE) mg/pair in the control (C) group to 6.9 +/- 1.4 (1.96SE) mg/pair in S (t = 56 days). The calculated first-order degradation rate constant for this loss was kd = 0.17 days-1 [half time (t1/2) = 4.1 days]. The estimated slow myosin (SM) isoform content decreased from 13.4 +/- 2.0 (1.96SE) mg/pair in C to 2.1 +/- 0.2 (1.96SE) mg/pair in S (kd = 0.19 days-1, t1/2 = 3.6 days). The relative proportion of other myosin isoforms was increased at 28 and 56 days of suspension, reflecting an apparent de novo synthesis and the loss of SM. Recovery of contractile protein after 28 days of suspension was slower for both the myofibril protein and the SM isoform (kd = 0.07 days-1, t1/2 = 10 days). These data suggest that loss of weight bearing specifically affected the mechanisms of contractile protein expression reflected in soleus muscle protein degradation processes. In addition, the expression of the myosin isoforms were apparently differentially affected by the loss of weight-bearing activity.

Protein metabolism and beta-myosin heavy-chain mRNA in unweighted soleus muscle

1989 ◽  
Vol 257 (2) ◽  
pp. R300-R305 ◽  
Author(s):  
D. B. Thomason ◽  
R. B. Biggs ◽  
F. W. Booth
Keyword(s):  
Protein Synthesis ◽  
Soleus Muscle ◽  
Time Course ◽  
Degradation Rate ◽  
Synthesis Rate ◽  
Protein Synthesis Rate ◽  
Hindlimb Unweighting ◽  
First Order ◽  
Degradation Rate Constant ◽  
Myofibril Protein

To investigate the relative influence of protein synthetic and degradative control mechanisms in vivo during skeletal muscle atrophy, we measured myofibril and total mixed protein synthesis rates in muscles of rats prevented from hindlimb weight-bearing for 5 h and 7 days. Protein synthesis rates were determined by infusing the animals with [3H]Leu for 5 h and measuring the specific activity of [3H]Leu in the aminoacyl-tRNA precursor and protein product fractions of the muscles. In the soleus muscle, myofibril protein synthesis rates decreased from a control value of 5.9 to 4.6%/day during 5 h of hindlimb unweighting and to 2.4%/day after 7 days of hindlimb unweighting. The relatively more phasic muscles (plantaris, medial gastrocnemius, quadriceps) showed a tendency for increased myofibril protein synthesis rates (117-127% of control) during the first 5 h followed by a decrease (46-62% of control) at 7 days of hindlimb unweighting. A predicted time course of soleus muscle myofibril protein degradation rate was obtained from a numerical model of the decrease in soleus myofibril protein synthesis rate as a first-order process [half-time (t1/2) = 0.3 day by least-squares fit] and the time course of soleus muscle myofibril protein previously observed with hindlimb unweighting (Thomason et al., J. Appl. Physiol. 63: 130-137, 1987). The degradation rate model makes specific, testable predictions for the mechanism of myofibril protein degradation during soleus muscle atrophy: 1) the first-order degradation rate constant does not obtain a fixed value over a 24-day period but is continuously changing throughout atrophy, and 2) the first-order degradation rate constant changes on a time scale slower than protein synthesis rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Time course adaptations in rat skeletal muscle isomyosins during compensatory growth and regression

1987 ◽  
Vol 63 (5) ◽  
pp. 2111-2121 ◽  
Author(s):  
R. W. Tsika ◽  
R. E. Herrick ◽  
K. M. Baldwin
Keyword(s):  
Skeletal Muscle ◽  
Atpase Activity ◽  
Time Course ◽  
Compensatory Growth ◽  
Myosin Isoforms ◽  
Plantaris Muscle ◽  
Slow Myosin ◽  
Protein Pool ◽  
Isoform Expression ◽  
Myofibril Protein

The purpose of this study was to ascertain the time course of change during both compensatory growth (hypertrophy) and subsequent growth regression on myosin isoform expression in rodent fast-twitch plantaris muscle in response to functional overload (induced by removal of synergists). Peak hypertrophy of the plantaris muscle (92%) occurred after 9 wk of overload. After 7 wk of overload regression (induced by a model of hindlimb unweighting), muscle weight returned to within 30% of control values. Myofibril protein content (mg/g muscle) remained relatively constant throughout the overload period but became significantly depressed relative to control values after 7 wk of regression. However, when expressed on a per muscle basis (mg/muscle) no differences existed at this time point (t = 7 wk regression). The distribution of native myosin isoforms in the myofibril protein pool of the overloaded plantaris muscle reflected a progressive increase (23% at t = 9 wk; P less than 0.001) in the relative proportion of slow myosin (Sm). This change was also accompanied by increases in intermediate myosin (Im) as well as the repression of the fast myosin one (Fm1) isoform (P less than 0.001). These shifts in Sm and Fm1 isoform expression were gradually reversed during the regression period, whereas Im remained elevated relative to control values. These adaptive changes in myosin isoform expression during both hypertrophy and regression were further supported by concomitant shifts in both myosin adenosinetriphosphatase (ATPase) activity (decreased during overload) and slow myosin light chain (SLC) expression. However, during regression the changes in myosin isoform expression and myosin ATPase were not as synchronous as they were during overload. Estimation of the mixed myosin heavy chain (MHC) half-life (t 1/2), using a linear model that assumes zero-order synthesis and first-order degradation kinetics, revealed t 1/2 values of approximately 19 and 10 days for the overload and regression periods, respectively. Collectively these data suggest that 1) skeletal muscle myosin isoforms and corresponding ATPase activity are in a dynamic state of change, although not completely synchronous, in response to altered muscle stress, and 2) the kinetics of change in the mixed MHC protein pool are slower during compensatory growth compared with regression of growth.

scholarly journals Effect of hindlimb unweighting on single soleus fiber maximal shortening velocity and ATPase activity

1993 ◽  
Vol 74 (6) ◽  
pp. 2949-2957 ◽  
Author(s):  
K. S. McDonald ◽  
R. H. Fitts
Keyword(s):  
Atpase Activity ◽  
Soleus Muscle ◽  
Time Course ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Maximal Velocity ◽  
Shortening Velocity ◽  
Hindlimb Unweighting ◽  
Fast Myosin ◽  
Highly Correlated

This study characterizes the time course of change in single soleus muscle fiber size and function elicited by hindlimb unweighting (HU) and analyzes the extent to which varying durations of HU altered maximal velocity of shortening (Vo), myofibrillar adenosinetriphosphatase (ATPase), and relative content of slow and fast myosin in individual soleus fibers. After 1, 2, or 3 wk of HU, soleus muscle bundles were prepared and stored in skinning solution at -20 degrees C. Single fibers were isolated and mounted between a motor arm and a transducer, and fiber force, Vo, and ATPase activity were measured. Fiber myosin content was determined by one-dimensional sodium dodecyl sulfate- (SDS) polyacrylamide gel electrophoresis. After 1, 2, and 3 wk of HU, soleus fibers exhibited a progressive reduction in fiber diameter (16, 22, and 42%, respectively) and peak force (42, 48, and 72%, respectively). Peak specific tension was significantly reduced after 1 wk of HU (18%) and showed no further change in 2–3 wk of HU. During 1 and 3 wk of HU, fiber Vo and ATPase showed a significant increase. By 3 wk, Vo had increased from 1.32 +/- 0.04 to 2.94 +/- 0.17 fiber lengths/s and fiber ATPase from 291 +/- 16 to 1,064 +/- 128 microM.min-1 x mm-3. The percent fibers expressing fast myosin heavy chain increased from 4% to 29% by 3 wk of HU, and Vo and ATPase activity within a fiber were highly correlated.(ABSTRACT TRUNCATED AT 250 WORDS)

Ontogenetic, gravity-dependent development of rat soleus muscle

2001 ◽  
Vol 280 (4) ◽  
pp. C1008-C1016 ◽  
Author(s):  
Yoshinobu Ohira ◽  
Takato Tanaka ◽  
Tomoo Yoshinaga ◽  
Fuminori Kawano ◽  
Takeshi Nomura ◽  
...  
Keyword(s):  
Soleus Muscle ◽  
Weight Bearing ◽  
Postnatal Period ◽  
Hindlimb Unloading ◽  
Full Weight Bearing ◽  
Type I ◽  
Myosin Isoforms ◽  
Normal Transition ◽  
Postural Muscle ◽  
Rat Soleus Muscle

We tested the hypothesis that rat soleus muscle fiber growth and changes in myosin phenotype during the postnatal, preweaning period would be largely independent of weight bearing. The hindlimbs of one group of pups were unloaded intermittently from postnatal day 4 to day 21: the pups were isolated from the dam for 5 h during unloading and returned for nursing for 1 h. Control pups were either maintained with the dam as normal or put on an alternating feeding schedule as described above. The enlargement of mass (∼3 times), increase in myonuclear number (∼1.6 times) and myonuclear domain (∼2.6 times), and transformation toward a slow fiber phenotype (from 56 to 70% fibers expressing type I myosin heavy chain) observed in controls were inhibited by hindlimb unloading. These properties were normalized to control levels or higher within 1 mo of reambulation beginning immediately after the unloading period. Therefore, chronic unloading essentially stopped the ontogenetic developmental processes of 1) net increase in DNA available for transcription, 2) increase in amount of cytoplasm sustained by that DNA pool, and 3) normal transition of myosin isoforms that occur in some fibers from birth to weaning. It is concluded that normal ontogenetic development of a postural muscle is highly dependent on the gravitational environment even during the early postnatal period, when full weight-bearing activity is not routine.

Role of weight-bearing function on expression of myosin isoforms during regeneration of rat soleus muscles

1996 ◽  
Vol 270 (3) ◽  
pp. C763-C771 ◽  
Author(s):  
X. A. Bigard ◽  
D. Merino ◽  
B. Serrurier ◽  
F. Lienhard ◽  
Y. C. Guezennec ◽  
...  
Keyword(s):  
Soleus Muscle ◽  
Weight Bearing ◽  
Muscle Fibers ◽  
Immunohistochemical Analysis ◽  
Normal Weight ◽  
Hindlimb Suspension ◽  
Myosin Isoforms ◽  
Homogeneous Population ◽  
Postural Load ◽  
Rat Soleus Muscle

The expression of myosin isoforms was studied in regenerated rat soleus muscle during either normal or altered postural activity. Regeneration was induced following injury by venom from the Notechis scutatus scutatus snake. Immunohistochemical analysis showed that, in regenerating soleus muscle after 3 wk of hindlimb suspension, nearly all fibers reacted positively with the myosin heavy chain (MHC) antibody associated with fast-twitch muscle fibers (fast MHC). When 3 wk of recovery with normal weight-bearing activity followed hindlimb suspension, the regeneration soleus muscle exhibited a nearly homogeneous staining with the MHC antibody associated with the slow-twitch muscle fibers (slow MHC). These findings were in accordance with quantitative analysis of the electrophoretic separation of the native myosin isoforms. Immunohistochemical data showed that removal of weight bearing in the 21-day old regenerated soleus muscles resulted in an increase in fast MHC expression. Together, the results of the present study clearly demonstrate that the postural load is an important component in the induction of slow MHC in regenerating muscle and that the control of the expression of MHC in muscle comprising a homogeneous population of fibers deriving from satellite cells appears more homogeneous and more complete than in a nondegenerated one.

Enhanced insulin action on glucose transport and insulin signaling in 7-day unweighted rat soleus muscle

2004 ◽  
Vol 97 (1) ◽  
pp. 63-71 ◽  
Author(s):  
Matthew P. O'Keefe ◽  
Felipe R. Perez ◽  
Julie A. Sloniger ◽  
Marc E. Tischler ◽  
Erik J. Henriksen
Keyword(s):  
Protein Expression ◽  
Tyrosine Phosphorylation ◽  
Glucose Transport ◽  
P38 Mapk ◽  
Soleus Muscle ◽  
Insulin Signaling ◽  
Insulin Action ◽  
Weight Bearing ◽  
Pi3 Kinase ◽  
Rat Soleus Muscle

Hindlimb suspension (HS), a model of simulated weightlessness, enhances insulin action on glucose transport in unweighted rat soleus muscle. In the present study, we tested the hypothesis that these changes in glucose transport in 3- and 7-day HS soleus of juvenile, female Sprague-Dawley rats were due to increased functionality of insulin signaling factors, including insulin receptor (IR), IR substrate-1 (IRS-1), phosphatidylinositol 3-kinase (PI3-kinase), and Akt. Insulin-stimulated (2 mU/ml) glucose transport was significantly ( P < 0.05) enhanced in 3- and 7-day HS soleus by 59 and 113%, respectively, compared with weight-bearing controls. Insulin-stimulated tyrosine phosphorylation of IR and Ser473 phosphorylation of Akt was not altered by unweighting. Despite decreased (34 and 64%) IRS-1 protein in 3- and 7-day HS soleus, absolute insulin-stimulated tyrosine phosphorylation of IRS-1 was not diminished, indicating relative increases in IRS-1 phosphorylation of 62 and 184%, respectively. In the 7-day HS soleus, this was accompanied by increased (47%) insulin-stimulated IRS-1 associated with the p85 subunit of PI3-kinase. Interestingly, the enhanced insulin-stimulated glucose transport in the unweighted soleus was not completely inhibited (89–92%) by wortmannin, a PI3-kinase inhibitor. Finally, protein expression and activation of p38 MAPK, a stress-activated serine/threonine kinase associated with insulin resistance, was decreased by 32 and 18% in 7-day HS soleus. These results indicate that the increased insulin action on glucose transport in the 7-day unweighted soleus is associated with increased insulin signaling through IRS-1 and PI3-kinase and decreased p38 MAPK protein expression. However, PI3-kinase-independent mechanisms must also play a small role in this adaptive response to HS.

Intermittent acceleration as a countermeasure to soleus muscle atrophy

1992 ◽  
Vol 72 (2) ◽  
pp. 428-433 ◽  
Author(s):  
D. S. D'Aunno ◽  
R. R. Robinson ◽  
G. S. Smith ◽  
D. B. Thomason ◽  
F. W. Booth
Keyword(s):  
Muscle Mass ◽  
Soleus Muscle ◽  
Important Determinant ◽  
Muscular Atrophy ◽  
Weight Bearing ◽  
Space Station ◽  
Hindlimb Unweighting ◽  
Ground Support ◽  
Postural Muscle ◽  
Centrifugation Protocol

The centrifuge proposed for the Space Station will most likely be used, in part, for countermeasure studies. At present, there is a paucity of information concerning the duration and frequency of acceleration necessary to counteract the atrophy process associated with microgravity. The present study was designed to investigate intermittent acceleration during non-weight bearing of the soleus muscle and its resultant effects on muscular atrophy. Each day rats were removed from hindlimbs suspension and accelerated to 1.2 g for four 15-min periods evenly spaced over a 12-h interval. The soleus muscle experienced non-weight bearing the remaining 23 h each day. This paradigm, when repeated for 7 days, did not completely maintain the mass of soleus muscle, which was 84% of control. Interestingly, the identical protocol utilizing ground support in lieu of acceleration successfully maintained the soleus muscle mass. The failure of the centrifugation protocol to adequately maintain soleus muscle mass might be due to an undefined stress placed on the animals inherent in centrifugation itself. This stress may also explain the transient decline in food intake of the intermittent acceleration group on the 2nd and 3rd days of treatment. Also, these data support the concept that the frequency of exposure, as opposed to the duration of exposure, to weight bearing during hindlimb unweighting seems to be the more important determinant of maintaining postural muscle mass.

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