scholarly journals Effects of fatigue and training on sarcoplasmic reticulum Ca2+ regulation in human skeletal muscle

2002 ◽  
Vol 92 (3) ◽  
pp. 912-922 ◽  
Author(s):  
Jia L. Li ◽  
Xiao N. Wang ◽  
Steve F. Fraser ◽  
Michael F. Carey ◽  
Tim V. Wrigley ◽  
...  
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Atpase Activity ◽  
Human Skeletal Muscle ◽  
Fiber Type ◽  
Vastus Lateralis ◽  
Human Muscle ◽  
Training Status ◽  
Type Ii ◽  
Muscle Biopsies ◽  
And Training

Little is known about fatigue and training effects on sarcoplasmic reticulum (SR) function in human muscle, and we therefore investigated this in eight untrained controls (UT), eight endurance-trained (ET), and eight resistance-trained athletes (RT). Muscle biopsies (vastus lateralis) taken at rest and after 50 maximal quadriceps contractions (180°/s, 0.5 Hz) were analyzed for fiber composition, metabolites and maximal SR Ca2+ release, Ca2+ uptake, and Ca2+-ATPase activity. Fatigue reduced ( P < 0.05) Ca2+ release (42.1 ± 3.8%, 43.4 ± 3.9%, 31.3 ± 6.1%), Ca2+ uptake (43.0 ± 5.2%, 34.1 ± 4.6%, 28.4 ± 2.8%), and Ca2+-ATPase activity (38.6 ± 4.2%, 48.5 ± 5.7%, 29.6 ± 5.0%), in UT, RT, and ET, respectively. These decreases were correlated with fatigability and with type II fiber proportion ( P < 0.05). Resting SR measures were correlated with type II proportion ( r ≥ 0.51, P < 0.05). ET had lower resting Ca2+ release, Ca2+ uptake, and Ca2+-ATPase ( P < 0.05) than UT and RT ( P < 0.05), probably because of their lower type II proportion; only minor effects were found in RT. Thus SR function is markedly depressed with fatigue in controls and in athletes, is dependent on fiber type, and appears to be minimally affected by chronic training status.

Oxidative capacity of human muscle fiber types: effects of age and training status

1995 ◽  
Vol 78 (6) ◽  
pp. 2033-2038 ◽  
Author(s):  
D. N. Proctor ◽  
W. E. Sinning ◽  
J. M. Walro ◽  
G. C. Sieck ◽  
P. W. Lemon
Keyword(s):  
Succinate Dehydrogenase ◽  
Vastus Lateralis ◽  
Muscle Fibers ◽  
Oxidative Capacity ◽  
Muscle Fiber Types ◽  
Type I ◽  
Fiber Types ◽  
Training Status ◽  
Type Ii ◽  
And Training

Morphometry and oxidative capacity of slow-twitch (type I) and fast-twitch (type IIa and IIb) muscle fibers obtained from vastus lateralis needle biopsies were compared between younger (21-30 yr) and older (51-62 yr) normal fit (maximal O2 uptake = 47.0 vs. 32.3 ml.kg-1.min-1) and endurance-trained (66.3 vs. 52.7 ml.kg-1.min-1) men (n = 6/group). The older groups had smaller type IIa (31%) and IIb (40%) fiber areas and fewer capillaries surrounding these fibers than did younger groups. The reduced type II fiber areas and capillary contacts associated with aging were also observed in the older trained men. However, the capillary supply per unit type II fiber area was not affected by age but was enhanced by training. Additionally, on the basis of quantitative histochemical analysis, succinate dehydrogenase activities of type IIa fibers in the older trained men [4.07 +/- 0.68 (SD) mmol.min-1.l-1] were similar to those observed in younger trained men (4.00 +/- 0.48 mmol.min-1.l-1) and twofold higher than in older normal fit men (2.01 +/- 0.65 mmol.min-1.l-1; age x fitness interaction, P < 0.05). Type I muscle fibers were unaffected by age but were larger and had more capillary contacts and higher succinate dehydrogenase activities in the trained groups. The findings of this study suggest that aging results in a decrease in type II fiber size and oxidative capacity in healthy men and that this latter effect can be prevented by endurance training. Conclusions regarding the effects of age and training status on muscle capillarization depend largely on how these data are expressed.

Human skeletal sarcoplasmic reticulum Ca2+ uptake and muscle function with aging and strength training

1999 ◽  
Vol 86 (6) ◽  
pp. 1858-1865 ◽  
Author(s):  
Sandra K. Hunter ◽  
Martin W. Thompson ◽  
Patricia A. Ruell ◽  
Alison R. Harmer ◽  
Jeanette M. Thom ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Resistance Training ◽  
Sarcoplasmic Reticulum ◽  
Atpase Activity ◽  
High Resistance ◽  
Elderly Women ◽  
Fiber Type ◽  
Vastus Lateralis ◽  
Type I ◽  
Fiber Types

This study investigated the adaptations of skeletal muscle sarcoplasmic reticulum (SR) Ca2+ uptake, relaxation, and fiber types in young (YW) and elderly women (EW) to high-resistance training. Seventeen YW (18–32 yr) and 11 EW (64–79 yr) were assessed for 1) electrically evoked relaxation time and rate of the quadriceps femoris; and 2) maximal rates of SR Ca2+ uptake and Ca2+-ATPase activity and relative fiber-type areas, analyzed from muscle biopsies of the vastus lateralis. EW had significantly slower relaxation rates and times, decreased SR Ca2+ uptake and Ca2+-ATPase activity, and a larger relative type I fiber area than did YW. A subgroup of 9 young (YWT) and 10 elderly women (EWT) performed 12 wk of high-resistance training (8 repetition maximum) of the quadriceps and underwent identical testing procedures pre- and posttraining. EWT significantly increased their SR Ca2+ uptake and Ca2+-ATPase activity in response to training but showed no alterations in speed of relaxation or relative fiber-type areas. In YWT none of the variables was altered after resistance training. These findings suggest that 1) a reduced SR Ca2+ uptake in skeletal muscle of elderly women was partially reversed with resistance training and 2) SR Ca2+ uptake in the vastus lateralis was not the rate-limiting mechanism for the slowing of relaxation measured from electrically evoked quadriceps muscle of elderly women.

Lactate transport studied in sarcolemmal giant vesicles from human muscle biopsies: relation to training status

1994 ◽  
Vol 77 (4) ◽  
pp. 1858-1862 ◽  
Author(s):  
H. Pilegaard ◽  
J. Bangsbo ◽  
E. A. Richter ◽  
C. Juel
Keyword(s):  
Fiber Type ◽  
Vastus Lateralis ◽  
High Volume ◽  
Type I ◽  
Training Status ◽  
Transport Capacity ◽  
Lactate Transport ◽  
Giant Vesicles ◽  
Trained Subjects ◽  
Muscle Biopsies

The present study examined sarcolemmal lactate transport capacity in humans of widely different training status. Muscle biopsies were obtained from m. vastus lateralis in 39 subjects divided into untrained (n = 13), trained (n = 7), and athlete [sprint runners (n = 2), endurance runners (n = 5), triathletes (n = 3), and road (n = 6) and track (n = 3) bicyclists] groups. From the biopsy sample giant vesicles were produced with collagenase treatment to determine the sarcolemmal lactate transport capacity, and histochemical analyses were made. The athletes had a higher capacity to transport lactate than the untrained and trained subjects (P < 0.01). Within the group of athletes, the bicyclists had a higher lactate transport capacity than the runners (P < 0.05), whereas there was no difference among trained subjects, runners, and triathletes. The lactate transport capacity was related to the occurrence of type I muscle fibers (r = 0.48, P < 0.01). The present results suggest that the capacity to transport lactate is higher in athletes than in untrained and less trained subjects. It might indicate that lactate transport capacity in human skeletal muscle can be changed by a high volume of training including frequent high-intensity sessions. In addition, sarcolemmal lactate transport capacity appears to be related to the fiber type distribution of a muscle.

Acute effects of taurine on sarcoplasmic reticulum Ca2+ accumulation and contractility in human type I and type II skeletal muscle fibers

2014 ◽  
Vol 117 (7) ◽  
pp. 797-805 ◽  
Author(s):  
T. L. Dutka ◽  
C. R. Lamboley ◽  
R. M. Murphy ◽  
G. D. Lamb
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Fiber Type ◽  
Vastus Lateralis ◽  
Muscle Fibers ◽  
Vastus Lateralis Muscle ◽  
Type I ◽  
Fiber Types ◽  
Type Ii ◽  
Contractile Apparatus ◽  
Type Ii Fibers

Taurine occurs in high concentrations in muscle and is implicated in numerous physiological processes, yet its effects on many aspects of contractility remain unclear. Using mechanically skinned segments of human vastus lateralis muscle fibers, we characterized the effects of taurine on sarcoplasmic reticulum (SR) Ca2+ accumulation and contractile apparatus properties in type I and type II fibers. Prolonged myoplasmic exposure (>10 min) to taurine substantially increased the rate of accumulation of Ca2+ by the SR in both fiber types, with no change in the maximum amount accumulated; no such effect was found with carnosine. SR Ca2+ accumulation was similar with 10 or 20 mM taurine, but was significantly slower at 5 mM taurine. Cytoplasmic taurine (20 mM) had no detectable effects on the responsiveness of the Ca2+ release channels in either fiber type. Taurine caused a small increase in Ca2+ sensitivity of the contractile apparatus in type I fibers, but type II fibers were unaffected; maximum Ca2+-activated force was unchanged in both cases. The effects of taurine on SR Ca2+ accumulation 1) only became apparent after prolonged cytoplasmic exposure, and 2) persisted for some minutes after complete removal of taurine from the cytoplasm, consistent with the hypothesis that the effects were due to an action of taurine from inside the SR. In summary, taurine potentiates the rate of SR Ca2+ uptake in both type I and type II human fibers, possibly via an action from within the SR lumen, with the degree of potentiation being significantly reduced at low physiological taurine levels.

Human muscle sarcoplasmic reticulum function during submaximal exercise in normoxia and hypoxia

2004 ◽  
Vol 97 (1) ◽  
pp. 180-187 ◽  
Author(s):  
T. A. Duhamel ◽  
H. J. Green ◽  
J. G. Perco ◽  
S. D. Sandiford ◽  
J. Ouyang
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Atpase Activity ◽  
Vastus Lateralis ◽  
Maximal Activity ◽  
Human Muscle ◽  
Hill Coefficient ◽  
Moderate Intensity ◽  
Vastus Lateralis Muscle ◽  
Moderate Intensity Exercise ◽  
Dependent Atpase

In this study, the response of the sarcoplasmic reticulum (SR) to prolonged exercise, performed in normoxia (inspired O2 fraction = 0.21) and hypoxia (inspired O2 fraction = 0.14) was studied in homogenates prepared from the vastus lateralis muscle in 10 untrained men (peak O2 consumption = 3.09 ± 0.25 l/min). In normoxia, performed at 48 ± 2.2% peak O2 consumption, maximal Ca2+-dependent ATPase activity was reduced by ∼25% at 30 min of exercise compared with rest (168 ± 10 vs. 126 ± 8 μmol·g protein−1·min−1), with no further reductions observed at 90 min (129 ± 6 μmol·g protein−1·min−1). No changes were observed in the Hill coefficient or in the Ca2+ concentration at half-maximal activity. The reduction in maximal Ca2+-dependent ATPase activity at 30 min of exercise was accompanied by oxalate-dependent reductions ( P < 0.05) in Ca2+ uptake by ∼20% (370 ± 22 vs. 298 ± 25 μmol·g protein−1·min−1). Ca2+ release, induced by 4-chloro- m-cresol and assessed into fast and slow phases, was decreased ( P < 0.05) by ∼16 and ∼32%, respectively, by 90 min of exercise. No differences were found between normoxia and hypoxia for any of the SR properties examined. It is concluded that the disturbances induced in SR Ca2+ cycling with prolonged moderate-intensity exercise in human muscle during normoxia are not modified when the exercise is performed in hypoxia.

Enhanced sarcoplasmic reticulum Ca2+ release following intermittent sprint training

2000 ◽  
Vol 279 (1) ◽  
pp. R152-R160 ◽  
Author(s):  
Niels Ørtenblad ◽  
Per K. Lunde ◽  
Klaus Levin ◽  
Jesper L. Andersen ◽  
Preben K. Pedersen
Keyword(s):  
Sarcoplasmic Reticulum ◽  
High Intensity ◽  
Vastus Lateralis ◽  
Ryanodine Receptors ◽  
Vastus Lateralis Muscle ◽  
Sprint Training ◽  
High Intensity Training ◽  
Before And After ◽  
Muscle Biopsies ◽  
Intensity Training

To evaluate the effect of intermittent sprint training on sarcoplasmic reticulum (SR) function, nine young men performed a 5 wk high-intensity intermittent bicycle training, and six served as controls. SR function was evaluated from resting vastus lateralis muscle biopsies, before and after the training period. Intermittent sprint performance (ten 8-s all-out periods alternating with 32-s recovery) was enhanced 12% ( P < 0.01) after training. The 5-wk sprint training induced a significantly higher ( P < 0.05) peak rate of AgNO3-stimulated Ca2+ release from 709 (range 560–877; before) to 774 (596–977) arbitrary units Ca2+ ⋅ g protein− 1 ⋅ min− 1(after). The relative SR density of functional ryanodine receptors (RyR) remained unchanged after training; there was, however, a 48% ( P < 0.05) increase in total number of RyR. No significant differences in Ca2+ uptake rate and Ca2+-ATPase capacity were observed following the training, despite that the relative density of Ca2+-ATPase isoforms SERCA1 and SERCA2 had increased 41% and 55%, respectively ( P < 0.05). These data suggest that high-intensity training induces an enhanced peak SR Ca2+ release, due to an enhanced total volume of SR, whereas SR Ca2+ sequestration function is not altered.

Tricarboxylic acid cycle intermediates in human muscle at rest and during prolonged cycling

1997 ◽  
Vol 272 (2) ◽  
pp. E239-E244 ◽  
Author(s):  
M. J. Gibala ◽  
M. A. Tarnopolsky ◽  
T. E. Graham
Keyword(s):  
Fiber Type ◽  
Tricarboxylic Acid Cycle ◽  
Vastus Lateralis ◽  
Tca Cycle ◽  
Tricarboxylic Acid ◽  
Human Muscle ◽  
Pool Size ◽  
Recruitment Pattern ◽  
Total Pool ◽  
Tca Cycle Intermediates

Previous studies have used the muscle concentration of citrate + malate + fumarate to estimate tricarboxylic acid (TCA) cycle pool size in humans [e.g., Am. J. Physiol. 259 (Cell Physiol. 28): C834-C841, 1990]. Our purpose was to quantify changes in individual TCA cycle intermediates (TCAI) and total pool size by measuring the concentrations of the eight TCAI in human muscle. Eight males cycled to exhaustion (Exh) at approximately 70% of their maximal oxygen uptake, and biopsies were obtained from the vastus lateralis at rest and during exercise. Succinyl-CoA was not consistently detectable, but the sum of the other seven TCAI was 1.23 +/- 0.04 mmol/kg dry wt at rest, 4.80 +/- 0.25 and 4.87 +/- 0.30 mmol/kg after 5 and 15 min of exercise, respectively, and 3.08 +/- 0.15 mmol/kg at Exh. Pool size during exercise was approximately 50% higher than that seen in rodent muscle after intense electrical stimulation (Eur. J. Biochem. 110: 371-377, 1980). Relative changes in individual TCAI were not uniform, and no one intermediate was "representative" of the changes in total pool size. We conclude that changes in specific intermediates or total pool size cannot be used as indicators of cycle flux and that the apparent species differences in total pool size may reflect differences in fiber type composition, recruitment pattern, or relative intensity of contraction.

scholarly journals Quantitative determination of Ca2+-dependent Mg2+-ATPase from sarcoplasmic reticulum in muscle biopsies

1989 ◽  
Vol 260 (2) ◽  
pp. 443-448 ◽  
Author(s):  
M E Everts ◽  
J P Andersen ◽  
T Clausen ◽  
O Hansen
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Soleus Muscle ◽  
Human Subjects ◽  
Vastus Lateralis ◽  
Total Concentration ◽  
Vastus Lateralis Muscle ◽  
Lateralis Muscle ◽  
32P Incorporation ◽  
Muscle Biopsies

The possibility of quantifying the total concentration of Ca2+-dependent Mg2+-ATPase of sarcoplasmic reticulum was investigated by measurement of the Ca2+-dependent steady-state phosphorylation from [gamma-32P]ATP and the Ca2+-dependent 3-O-methylfluorescein phosphatase (3-O-MFPase) activity in crude muscle homogenates. The Ca2+-dependent phosphorylation at 0 degree C (mean +/- S.E.) was 40.0 +/- 2.5 (n = 6) and 6.2 +/- 0.7 (n = 4) nmol/g wet wt. in rat extensor digitorum longus (EDL) and soleus muscle, respectively (P less than 0.001). The Ca2+-dependent 3-O-MFPase activity at 37 degrees C was 1424 +/- 238 (n = 6) and 335 +/- 56 (n = 4) nmol/min per g wet wt. in rat EDL and soleus muscle, respectively (P less than 0.01). The molecular activity calculated from these measurements amounted to 35 +/- 5 min-1 (n = 6) and 55 +/- 10 min-1 (n = 4) for EDL and soleus muscle respectively. These values were not different from the molecular activity calculated for purified Ca2+-ATPase (36 min-1). The Ca2+-dependent 32P incorporation in soleus muscle decreased in the order mice greater than rats greater than guinea pigs. In EDL muscles from hypothyroid rats at a 30% reduction of the Ca2+-dependent phosphorylation was observed. The Ca2+-dependent phosphorylation in vastus lateralis muscle from three human subjects amounted to 4.5 +/- 0.8 nmol/g wet wt. It is concluded that measurement of the Ca2+-dependent phosphorylation allows rapid and reproducible quantification of the concentration of Ca2+-dependent Mg2+-ATPase of sarcoplasmic reticulum. Since only 20-60 mg of tissue is required for the measurements, the method can also be used for biopsies obtained in clinical studies.

Effects of prior exercise and a low-carbohydrate diet on muscle sarcoplasmic reticulum function during cycling in women

2006 ◽  
Vol 101 (3) ◽  
pp. 695-706 ◽  
Author(s):  
T. A. Duhamel ◽  
H. J. Green ◽  
J. G. Perco ◽  
J. Ouyang
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Atpase Activity ◽  
Vastus Lateralis ◽  
Phase 1 ◽  
Vastus Lateralis Muscle ◽  
Low Carbohydrate Diet ◽  
Hill Slope ◽  
Low Carbohydrate ◽  
Exercise Induced

The effects of exercise and diet on sarcoplasmic reticulum Ca2+-cycling properties in female vastus lateralis muscle were investigated in two groups of women following four different conditions. The conditions were 4 days of a low-carbohydrate (Lo CHO) and glycogen-depleting exercise plus a Lo CHO diet (Ex + Lo CHO) ( experiment 2) and 4 days of normal CHO (Norm CHO) and glycogen-depleting exercise plus Norm CHO (Ex + Norm CHO) ( experiment 1). Peak aerobic power (V̇o2peak) was 38.1 ± 1.4 (SE); n = 9 and 35.6 ± 1.4 ml·kg−1·min−1; n = 9, respectively. Sarcoplasmic reticulum properties measured in vitro in homogenates (μmol·g protein−1·min−1) indicated exercise-induced reductions ( P < 0.05) in maximal Ca2+-ATPase activity (0 > 30, 60 min > fatigue), Ca2+ uptake (0 > 30 > 60 min, fatigue), and Ca2+ release, both phase 1 (0, 30 > 60 min, fatigue) and phase 2 (0 > 30, 60 min, fatigue; 30 min > fatigue) in Norm CHO. Exercise was without effect in altering the Hill slope ( nH), defined as the slope of relationship between Ca2+-ATPase activity and Ca2+ concentration. No differences were observed between Norm CHO and Ex+Norm CHO. Compared with Norm CHO, Lo CHO resulted in a lower ( P < 0.05) Ca2+ uptake, phase 1 Ca2+ release (30 min), and nH. Ex + Lo CHO resulted in a greater ( P < 0.05) Ca2+ uptake and nH compared with Lo CHO. The results demonstrate that Lo CHO alone can disrupt SR Ca2+ cycling and that, with the exception of Ca2+ release, a glycogen-depleting session of exercise before Lo CHO can reverse the effects.

scholarly journals Adaptations in human muscle sarcoplasmic reticulum to prolonged submaximal training

2003 ◽  
Vol 94 (5) ◽  
pp. 2034-2042 ◽  
Author(s):  
H. J. Green ◽  
C. S. Ballantyne ◽  
J. D. MacDougall ◽  
M. A. Tarnopolsky ◽  
J. D. Schertzer
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Atpase Activity ◽  
Vastus Lateralis ◽  
Training Session ◽  
Maximal Activity ◽  
Hill Coefficient ◽  
Protein Levels ◽  
Plasmic Reticulum ◽  
Cycle Training ◽  
The Hill

In this study, we employed single-leg submaximal cycle training, conducted over a 10-wk period, to investigate adaptations in sarcoplasmic reticulum (SR) Ca2+-regulatory proteins and processes of the vastus lateralis. During the final weeks, the untrained volunteers (age 21.4 ± 0.3 yr; means ± SE, n = 10) were exercising 5 times/wk and for 60 min/session. Analyses were performed on tissue extracted by needle biopsy ∼4 days after the last training session. Compared with the control leg, the trained leg displayed a 19% reduction ( P < 0.05) in homogenate maximal Ca2+-ATPase activity (192 ± 11 vs. 156 ± 18 μmol · g protein−1 · min−1), a 4.3% increase ( P < 0.05) in pCa50, defined as the Ca2+ concentration at half-maximal activity (6.01 ± 0.05 vs. 6.26 ± 0.07), and no change in the Hill coefficient (1.75 ± 0.15 vs. 1.76 ± 0.21). Western blot analysis using monoclonal antibodies (7E6 and A52) revealed a 13% lower ( P < 0.05) sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) 1 in trained vs. control in the absence of differences in SERCA2a. Training also resulted in an 18% lower ( P < 0.05) SR Ca2+ uptake and a 26% lower ( P < 0.05) Ca2+ release. It is concluded that a downregulation in SR Ca2+ cycling in vastus lateralis occurs with aerobic-based training, which at least in the case of Ca2+ uptake can be explained by reduction in Ca2+-ATPase activity and SERCA1 protein levels.

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