Metabolic and sarcoplasmic reticulum Ca2+ cycling responses in human muscle 4 days following prolonged exercise

2005 ◽  
Vol 83 (7) ◽  
pp. 643-655 ◽  
Author(s):  
T A Duhamel ◽  
H J Green ◽  
J G Perco ◽  
J Ouyang
Keyword(s):  
Sarcoplasmic Reticulum ◽  
G Protein ◽  
Muscle Glycogen ◽  
Prolonged Exercise ◽  
Contractile Activity ◽  
Phase 1 ◽  
High Energy ◽  
Vastus Lateralis Muscle ◽  
Ionophore A23187 ◽  
High Energy Phosphates

This study investigated the effects of prolonged exercise on muscle sarcoplasmic reticulum (SR) Ca2+ cycling properties and the metabolic responses with and without a session of exercise designed to reduce muscle glycogen reserves while on a normal carbohydrate (CHO) diet. Eight untrained males (VO2peak = 3.81 ± 0.12 L/min, mean ± SE) performed a standardized cycle-to-fatigue at 55% VO2peak while on a normal CHO diet (Norm CHO) and 4 days following prolonged exercise while on a normal CHO diet (Ex+Norm CHO). Compared to rest, exercise in Norm CHO to fatigue resulted in significant reductions (p < 0.05) in Ca2+ uptake (3.17 ± 0.21 vs. 2.47 ± 0.12 µmol·(g protein)–1·min–1), maximal Ca2+ ATPase activity (Vmax, 152 ± 12 vs. 119 ± 9 µmol·(g protein)–1·min–1) and both phase 1 (15.1 ± 0.98 vs. 13.1 ± 0.28 µmol·(g protein)–1·min–1) and phase 2 (6.56 ± 0.33 vs. 4.91 ± 0.28 µmol·(g protein)–1·min–1) Ca2+ release in vastus lateralis muscle. No differences were observed between Norm CHO and Ex-Norm CHO in the response of these properties to exercise. Compared with Norm CHO, Ex+Norm CHO resulted in higher (p < 0.05) resting Ca2+ uptake (3.17 ± 0.21 vs. 3.49 ± 0.24 µmol·(g protein)·min–1 and higher ionophore ratio, defined as the ratio of Vmax measured with and without the Ca2+-ionophore A23187, (2.3 ± 0.3 vs. 4.4 ± 0.3 µmol·(g protein)·min–1) at fatigue. No differences were observed between conditions in the concentration of muscle glycogen, the high-energy phosphates (ATP and PCr), or metabolites (Pi, Cr, and lactate). Ex+Norm CHO also failed to modify the exercise-induced changes in CHO and fat oxidation. We conclude that prolonged exercise to fatigue performed 4 days following glycogen-depleting exercise while on a normal CHO diet elevates resting Ca2+ uptake and prevents increases in SR membrane permeability to Ca2+ as measured by the ionophore ratio. Key words: Ca2+ cycling, glycogen depletion, contractile activity, recovery.

Prolonged exercise to fatigue in humans impairs skeletal muscle Na+-K+-ATPase activity, sarcoplasmic reticulum Ca2+ release, and Ca2+ uptake

2004 ◽  
Vol 97 (4) ◽  
pp. 1414-1423 ◽  
Author(s):  
James A. Leppik ◽  
Robert J. Aughey ◽  
Ivan Medved ◽  
Ian Fairweather ◽  
Michael F. Carey ◽  
...  
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Atpase Activity ◽  
G Protein ◽  
Uptake Rate ◽  
Prolonged Exercise ◽  
Transport Processes ◽  
Vastus Lateralis Muscle ◽  
Ouabain Binding ◽  
Exercise In Humans

Prolonged exhaustive submaximal exercise in humans induces marked metabolic changes, but little is known about effects on muscle Na+-K+-ATPase activity and sarcoplasmic reticulum Ca2+ regulation. We therefore investigated whether these processes were impaired during cycling exercise at 74.3 ± 1.2% maximal O2 uptake (mean ± SE) continued until fatigue in eight healthy subjects (maximal O2 uptake of 3.93 ± 0.69 l/min). A vastus lateralis muscle biopsy was taken at rest, at 10 and 45 min of exercise, and at fatigue. Muscle was analyzed for in vitro Na+-K+-ATPase activity [maximal K+-stimulated 3- O-methylfluorescein phosphatase (3- O-MFPase) activity], Na+-K+-ATPase content ([3H]ouabain binding sites), sarcoplasmic reticulum Ca2+ release rate induced by 4 chloro- m-cresol, and Ca2+ uptake rate. Cycling time to fatigue was 72.18 ± 6.46 min. Muscle 3- O-MFPase activity (nmol·min−1·g protein−1) fell from rest by 6.6 ± 2.1% at 10 min ( P < 0.05), by 10.7 ± 2.3% at 45 min ( P < 0.01), and by 12.6 ± 1.6% at fatigue ( P < 0.01), whereas 3[H]ouabain binding site content was unchanged. Ca2+ release (mmol·min−1·g protein−1) declined from rest by 10.0 ± 3.8% at 45 min ( P < 0.05) and by 17.9 ± 4.1% at fatigue ( P < 0.01), whereas Ca2+ uptake rate fell from rest by 23.8 ± 12.2% at fatigue ( P = 0.05). However, the decline in muscle 3- O-MFPase activity, Ca2+ uptake, and Ca2+ release were variable and not significantly correlated with time to fatigue. Thus prolonged exhaustive exercise impaired each of the maximal in vitro Na+-K+-ATPase activity, Ca2+ release, and Ca2+ uptake rates. This suggests that acutely downregulated muscle Na+, K+, and Ca2+ transport processes may be important factors in fatigue during prolonged exercise in humans.

Manipulation of dietary carbohydrates after prolonged effort modifies muscle sarcoplasmic reticulum responses in exercising males

2006 ◽  
Vol 291 (4) ◽  
pp. R1100-R1110 ◽  
Author(s):  
T. A. Duhamel ◽  
J. G. Perco ◽  
H. J. Green
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Muscle Glycogen ◽  
Prolonged Exercise ◽  
Vastus Lateralis ◽  
Phase 1 ◽  
Phase 2 ◽  
Dietary Carbohydrates ◽  
Carbohydrate Diet ◽  
Exercise Induced ◽  
Total Muscle

The hypothesis tested was that disturbances in the sarcoplasmic reticulum (SR) Ca2+-cycling responses to exercise would associate with muscle glycogen reserves. Ten untrained males [peak O2consumption (V̇o2 peak) = 3.41 ± 0.20 (SE) l/min] performed a standardized cycle test (∼70% V̇o2 peak) on two occasions, namely, following 4 days of a high (Hi CHO)- and 4 days of a low (Lo CHO)-carbohydrate diet. Both Hi CHO and Lo CHO were preceded by a session of prolonged exercise designed to deplete muscle glycogen. SR Ca2+cycling in crude homogenates prepared from vastus lateralis samples indicated higher ( P < 0.05) Ca2+uptake (μM·g protein−1·min−1) in Hi CHO compared with Lo CHO at 30 min (2.93 ± 0.10 vs. 2.23 ± 0.12) and at 67 min (2.77 ± 0.16 vs. 2.10 ± 0.12) of exercise, the point of fatigue in Lo CHO. Similar effects ( P < 0.05) were noted between conditions for maximal Ca2+-ATPase (μM·g protein−1·min−1) at 30 min (142 ± 8.5 vs. 107 ± 5.0) and at 67 min (130 ± 4.5 vs. 101 ± 4.7). Both phase 1 and phase 2 Ca2+release were 23 and 37% higher ( P < 0.05) at 30 min of exercise and 15 and 34% higher ( P < 0.05), at 67 min during Hi CHO compared with Lo CHO, respectively. No differences between conditions were observed at rest for any of these SR properties. Total muscle glycogen (mmol glucosyl units/kg dry wt) was higher ( P < 0.05) in Hi CHO compared with Lo CHO at rest (+36%), 30 min (+53%), and at 67 min (+44%) of cycling. These results indicate that exercise-induced reductions in SR Ca2+-cycling properties occur earlier in exercise during low glycogen states compared with high glycogen states.

Responses of beta-adrenoceptor in rat soleus to phosphorus compound levels and/or unloading

1994 ◽  
Vol 266 (5) ◽  
pp. C1257-C1262 ◽  
Author(s):  
Y. Ohira ◽  
K. Saito ◽  
T. Wakatsuki ◽  
W. Yasui ◽  
T. Suetsugu ◽  
...  
Keyword(s):  
Contractile Activity ◽  
Creatine Supplementation ◽  
High Energy ◽  
Hindlimb Suspension ◽  
Phosphorus Compounds ◽  
High Energy Phosphates ◽  
High Energy Phosphate ◽  
Gravitational Unloading ◽  
Beta Adrenoceptor ◽  
Muscle Contractile

Responses of beta-adrenoceptor (beta-AR) in rat soleus to gravitational unloading and/or changes in the levels of phosphorus compounds by feeding either creatine or its analogue beta-guanidinopropionic acid (beta-GPA) were studied. A decrease in the density of beta-AR (about -35%) was induced by 10 days of hindlimb suspension, but the affinity of the receptor was unaffected. Suspension unloading tended to increase the levels of adenosine triphosphate and phosphocreatine and decrease inorganic phosphate. Even without unloading, the beta-AR density decreased after an oral creatine supplementation (about -20%), which also tended to elevate the high-energy phosphate levels in muscle. However, an elevation of beta-AR density was induced (about +36%) after chronic depletion of high-energy phosphates by feeding beta-GPA (about +125%). Data suggest that the density of beta-AR in muscle is elevated if the high-energy phosphate contents are chronically decreased and vice versa. However, it may not be directly related to the degree of muscle contractile activity.

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.

Contractile and metabolic effects of increased creatine kinase activity in mouse skeletal muscle

1996 ◽  
Vol 270 (4) ◽  
pp. C1236-C1245 ◽  
Author(s):  
B. B. Roman ◽  
J. M. Foley ◽  
R. A. Meyer ◽  
A. P. Koretsky
Keyword(s):  
Skeletal Muscle ◽  
Creatine Kinase ◽  
Kinase Activity ◽  
Contractile Function ◽  
Contractile Activity ◽  
High Energy ◽  
Metabolic Effects ◽  
High Energy Phosphates ◽  
Lactate Dehydrogenase Activity ◽  
B Subunit

The effects of increased expression of creatine kinase (CK) in skeletal muscle were studied in control and transgenic animals homozygous for expression of the B subunit of CK. CK activity was 47% higher in transgenic gastrocnemius muscle. The CK activity was distributed as follows: 45 +/- 1% MM dinner, 31 +/- 4% MB dimer, and 22 +/- 5% BB dimer. No significant differences in metabolic or contractile proteins were detected except for a 22% decrease in lactate dehydrogenase activity and a 9% decrease in adenylate kinase activity. The only significant effect in contractile activity was that the rise time of a 5-s isometric contraction was 28% faster in the transgenic muscle. 31P nuclear magnetic resonance (NMR) spectra were obtained from control and transgenic muscles during mechanical activation, and there were no NMR measurable differences detected. These results indicate that a 50% increase in CK activity due to expression of the B subunit does not have large effects on skeletal muscle metabolism or contractile function. Therefore, control muscle has sufficient CK activity to keep up with changes in cellular high-energy phosphates except during the early phase of intense contractile activity.

EFFECTS OF DIETARY MANIPULATION ON MUSCLE GLYCOGEN AND SARCOPLASMIC RETICULUM FUNCTION DURING PROLONGED EXERCISE

2001 ◽  
Vol 33 (5) ◽  
pp. S297
Author(s):  
H Kollias ◽  
T Duhamel ◽  
R Tupling ◽  
S Sandiford ◽  
J Schertzer ◽  
...  
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Muscle Glycogen ◽  
Prolonged Exercise ◽  
Dietary Manipulation

A simple analysis of the "phosphocreatine shuttle"

1984 ◽  
Vol 246 (5) ◽  
pp. C365-C377 ◽  
Author(s):  
R. A. Meyer ◽  
H. L. Sweeney ◽  
M. J. Kushmerick
Keyword(s):  
Contractile Activity ◽  
High Energy ◽  
General Notion ◽  
Facilitated Diffusion ◽  
High Energy Phosphates ◽  
Intracellular Diffusion ◽  
Metabolic Reactions ◽  
Total Creatine ◽  
Phosphocreatine Shuttle ◽  
In Cells

The diffusive mobility of solutes chemically connected by reversible reactions in cells is analyzed as a problem of facilitated diffusion. By this term we mean that the diffusive flux of any substance, X, which is in one metabolic pathway, is effectively increased when it participates in a second and equilibrium reaction with another substance Y because the total flux of X in the pathway is the sum of the fluxes of X and Y. This notion is generalized and is seen to include the familiar enhanced intracellular diffusion of oxygen by oxymyoglobin. In this framework the function of creatine kinase (CK) is seen to have two aspects: 1) phosphocreatine (PCr) via the CK reaction buffers the cellular ATP and ADP concentrations and 2) transport of high-energy phosphates is predominantly in the chemical form of PCr. This predominance of PCr is a consequence of the maintained ATP, ADP, and total creatine levels and of the apparent equilibrium constant of the reaction. Thus experimental results demonstrating the transport aspects of the CK reaction emphasize only one feature of a more general notion of facilitated diffusion by near-equilibrium metabolic reactions and do not per se establish the existence of any physical or functional compartmentation of ATP, ADP, PCr, or creatine. PCr can be a large source for increasing inorganic phosphate levels during contractile activity, possibly as a metabolic regulator. Neither the transport nor buffer aspects can be quantitatively important in cells with small distances between ATP-utilizing and ATP-generating sites, such as is the case with cardiac myofibrils and mitochondria.

scholarly journals Muscle metabolic, SR Ca2+-cycling responses to prolonged cycling, with and without glucose supplementation

2007 ◽  
Vol 103 (6) ◽  
pp. 1986-1998 ◽  
Author(s):  
T. A. Duhamel ◽  
H. J. Green ◽  
R. D. Stewart ◽  
K. P. Foley ◽  
I. C. Smith ◽  
...  
Keyword(s):  
Prolonged Exercise ◽  
Vastus Lateralis ◽  
Phase 1 ◽  
Vastus Lateralis Muscle ◽  
Release Rates ◽  
Oxidation Rates ◽  
Lateralis Muscle ◽  
Blood Glucose Homeostasis ◽  
Exercise Induced ◽  
Glucose Supplementation

This study investigated the effects of prolonged exercise, with and without glucose supplementation, on metabolism and sarcoplasmic reticulum (SR) Ca2+-handling properties in working vastus lateralis muscle. Fifteen untrained volunteers [peak O2consumption (V̇o2peak) = 3.45 ± 0.17 l/min; mean ± SE] cycled at ∼60% V̇o2peakon two occasions, during which they were provided with either an artificially sweetened placebo beverage (NG) or a 6% glucose (G) beverage (∼1.00 g carbohydrate/kg body mass). Beverage supplementation started at 30 min of exercise and continued every 15 min thereafter. SR Ca2+handling, metabolic, and substrate responses were assessed in tissue extracted from the vastus lateralis at rest, after 30 min and 90 min of exercise, and at fatigue in both conditions. Plasma glucose during G was 15–23% higher ( P < 0.05) than those observed during NG following 60 min of exercise until fatigue. Cycle time to fatigue was increased ( P < 0.05) by ∼19% during G (137 ± 7 min) compared with NG (115 ± 6 min). Prolonged exercise reduced ( P < 0.05) maximal Ca2+-ATPase activity (−18.4%), SR Ca2+uptake (−27%), and both Phase 1 (−22.2%) and Phase 2 (−34.2%) Ca2+-release rates during NG. The exercise-induced reductions in SR Ca2+-cycling properties were not altered during G. The metabolic responses to exercise were all unaltered by glucose supplementation, since no differences in respiratory exchange ratios, carbohydrate and lipid oxidation rates, and muscle metabolite and glycogen contents were observed between NG and G. These results indicate that the maintenance of blood glucose homeostasis by glucose supplementation is without effect in modifying the muscle metabolic, endogenous glycogen, or SR Ca2+-handling responses.

Skeletal muscle ammonia production and repeated, intense exercise in humans

1993 ◽  
Vol 71 (7) ◽  
pp. 484-490 ◽  
Author(s):  
T. Graham ◽  
J. Bangsbo ◽  
B. Saltin
Keyword(s):  
Muscle Glycogen ◽  
Intermittent Exercise ◽  
Lactate Production ◽  
Knee Extensor ◽  
Creatine Phosphate ◽  
High Energy ◽  
High Energy Phosphates ◽  
Wet Weight ◽  
Exercise Fatigue ◽  
The Impact

We investigated the impact of repeated, high-intensity exercise on NH3 metabolism using the single-leg knee extensor model. The muscle glycogen level would be lowered by the initial exercise and low glycogen may stimulate NH3 production independent of any other effects of previous exercise. Therefore a high muscle glycogen condition was included in the protocol so that the pre-exercise glycogen concentration would be at least at a normal resting level for the second exercise. The subjects (n = 6) used previous exercise and (or) diet to begin the exercise with either normal (87.0 ± 14.4 mmol/kg wet weight) or high (176.8 ± 22.9 mmol/kg wet weight) glycogen (C and HG, respectively) in the quadriceps. They exercised (Ex1) one leg to exhaustion (140% leg [Formula: see text]), rested 1 h, repeated the exercise (Ex2), and then repeated the protocol with the opposite leg. The exercise durations of Ex1 and Ex2, respectively, for C were 2.82 ± 0.51 and 2.47 ± 0.47 min (p < 0.05) and for HG were 2.92 ± 0.57 and 2.77 ± 0.50 min. The NH3 efflux was reduced (p < 0.05) from Ex1 to Ex2 in both C (516 ± 159 and 250 ± 69 μmol, respectively) and HG (618 ± 233 and 275 ± 124 μmol, respectively). While NH3 efflux was virtually identical between C and HG in both Ex1 and Ex 2, HG consistently had a greater arterial NH3 concentration (p < 0.05). The decreased efflux in Ex2 compared with Ex1 was not due to greater accumulation of muscle NH3. The changes in creatine phosphate and ATP were very similar in all four exercises; however, the reduced NH3 response in Ex2 was associated with less net lactate production and presumably less muscle acidosis.Key words: AMP deaminase, lactate, purine nucleotide cycle, high energy phosphates, intermittent exercise, fatigue, glycogen.

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