Effects of tissue fractionation on exercise-induced alterations in SR function in rat gastrocnemius muscle

1996 ◽  
Vol 80 (3) ◽  
pp. 940-948 ◽  
Author(s):  
E. R. Chin ◽  
H. J. Green
Keyword(s):  
Atpase Activity ◽  
Treadmill Running ◽  
Sr Protein ◽  
Isolation Techniques ◽  
Exercise Induced ◽  
Gastrocnemius Muscles ◽  
Whole Muscle ◽  
Tissue Fractionation ◽  
Muscle Homogenate

Because studies into exercise-induced alterations in sarcoplasmic reticulum (SR) Ca2+ sequestration have produced conflicting reports, we have hypothesized that the differences in SR Ca(2+)-adenosinetriphosphatase (ATPase) activity and Ca2+ uptake in SR fractions observed in different studies are due to different SR isolation techniques. To investigate this possibility, rat white and red gastrocnemius muscles from control and run animals were studied by using two conventional isolation techniques to obtain a crude microsomal fraction and an isolated SR vesicle (SRV) fraction. Indexes of CM and SRV function were compared with measurements from whole muscle homogenate. Treadmill running to exhaustion did not alter SR protein yields, percent SR extraction, or basal or Ca(2+)-ATPase purification in either fraction. Ca(2+)-activated ATPase activity was not altered by exercise in any of the fractions examined, but Ca2+ uptake was reduced in the homogenates (9.48 +/- 1.4 to 6.90 +/- 0.8 nmol . mg-1.min-1) and SRV fractions (84.0 +/- 11.5 to 50.7 +/- 14.0 nmol . mg-1.min-1) from the red gastrocnemius at free Ca2+ concentrations of 600-700 nM. These data indicate that reductions in SR Ca2+ uptake are dissociated from changes in Ca(2+)-ATPase in vitro and occur only in a specific population of vesicles. The mechanisms underlying these alterations are not known but may involve a reduction in the number of Ca(2+)-ATPase enzymes or a selective sedimentation of damaged vesicles in the SRV fraction.

scholarly journals Exercise-induced protection against reperfusion arrhythmia involves stabilization of mitochondrial energetics

2016 ◽  
Vol 310 (10) ◽  
pp. H1360-H1370 ◽  
Author(s):  
Rick J. Alleman ◽  
Alvin M. Tsang ◽  
Terence E. Ryan ◽  
Daniel J. Patteson ◽  
Joseph M. McClung ◽  
...  
Keyword(s):  
Simultaneous Measurement ◽  
Cardiac Electrophysiology ◽  
Ischemia Reperfusion ◽  
Antiarrhythmic Effect ◽  
Treadmill Running ◽  
Sprague Dawley ◽  
Isolated Mitochondria ◽  
Reperfusion Arrhythmia ◽  
Exercise Induced

Mitochondria influence cardiac electrophysiology through energy- and redox-sensitive ion channels in the sarcolemma, with the collapse of energetics believed to be centrally involved in arrhythmogenesis. This study was conducted to determine if preservation of mitochondrial membrane potential (ΔΨm) contributes to the antiarrhythmic effect of exercise. We utilized perfused hearts, isolated myocytes, and isolated mitochondria exposed to metabolic challenge to determine the effects of exercise on cardiac mitochondria. Hearts from sedentary (Sed) and exercised (Ex; 10 days of treadmill running) Sprague-Dawley rats were perfused on a two-photon microscope stage for simultaneous measurement of ΔΨm and ECG. After ischemia-reperfusion, the collapse of ΔΨm was commensurate with the onset of arrhythmia. Exercise preserved ΔΨm and decreased the incidence of fibrillation/tachycardia ( P < 0.05). Our findings in intact hearts were corroborated in isolated myocytes exposed to in vitro hypoxia-reoxygenation, with Ex rats demonstrating enhanced redox control and sustained ΔΨm during reoxygenation. Finally, we induced anoxia-reoxygenation in isolated mitochondria using high-resolution respirometry with simultaneous measurement of respiration and H2O2. Mitochondria from Ex rats sustained respiration with lower rates of H2O2 emission than Sed rats. Exercise helps sustain postischemic mitochondrial bioenergetics and redox homeostasis, which is associated with preserved ΔΨm and protection against reperfusion arrhythmia. The reduction of fatal ventricular arrhythmias through exercise-induced mitochondrial adaptations indicates that mitochondrial therapeutics may be an effective target for the treatment of heart disease.

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 Effects of chronic nitric oxide synthase inhibition on responses to acute exercise in swine

2008 ◽  
Vol 104 (1) ◽  
pp. 186-197 ◽  
Author(s):  
Richard M. McAllister ◽  
Sean C. Newcomer ◽  
Eric R. Pope ◽  
James R. Turk ◽  
M. Harold Laughlin
Keyword(s):  
Nitric Oxide ◽  
Acute Exercise ◽  
Maximal Exercise ◽  
Tap Water ◽  
Treadmill Running ◽  
Blood Flows ◽  
No Formation ◽  
Exercise Induced ◽  
Oxide Synthase

Nitric oxide (NO) is potentially involved in several responses to acute exercise. We tested the hypotheses that inhibition of NO formation reduces maximal O2 delivery to muscle, but does not affect O2 utilization by muscle, therefore lowering maximal O2 consumption. To test these hypotheses, swine (∼30 kg) drank either tap water (Con, n = 25) or water with NG-nitro-l-arginine methyl ester (8.0 ± 0.4 mg·kg−1·day−1 for ≥4 wk; LN, n = 24). Treatment efficacy was reflected by higher mean arterial pressure and lower plasma NO metabolite concentration in LN than Con (both P < 0.05). Swine completed two graded treadmill running tests to maximum. In the first test, O2 consumption was determined at rest through maximal exercise intensity. O2 consumption did not differ between groups at rest or at most exercise intensities, including maximum (Con, 40.8 ± 1.8 ml·min−1·kg−1; LN, 40.4 ± 2.9; not significant). In the second test, tissue-specific blood flows were determined using the radiolabeled-microsphere technique. At rest, blood flows were lower ( P < 0.05) in LN compared with Con for a number of tissues, including kidney, adrenal, lung, and several skeletal muscles. During both submaximal and maximal exercise, however, blood flows were similar between Con and LN for all 16 muscles examined; only blood flows to kidney (Con, 99 ± 16 ml·min−1·100 g; LN, 55 ± 15; P < 0.05) and pancreas (Con, 25 ± 7; LN, 6 ± 2; P < 0.05) were lower in LN at maximum. Endothelium-dependent, but not -independent, relaxation of renal arterial segments was reduced ( P < 0.05) in vitro. These data indicate that exercise-induced increases in muscle blood flows are maintained with chronic inhibition of NO formation and that maximal O2 consumption is therefore preserved. Redundant vasodilatory pathways and/or upregulation of these pathways may underlie these findings.

Oxygen consumption and oxidative capacity of muscles from young obese and nonobese Zucker rats

1984 ◽  
Vol 247 (5) ◽  
pp. R911-R917 ◽  
Author(s):  
G. M. Wardlaw ◽  
M. L. Kaplan
Keyword(s):  
Citrate Synthase ◽  
Oxidative Capacity ◽  
Zucker Rats ◽  
Metabolic Efficiency ◽  
O2 Consumption ◽  
Respiration Rates ◽  
Obese Rats ◽  
Whole Muscle ◽  
Muscle Homogenate

The contribution of muscle tissue to the increased metabolic efficiency of the obese (fa/fa) Zucker rat at 6 wk of age was examined. In vitro O2 consumption was similar in obese and nonobese soleus and extensor digitorum longus (EDL) muscles, whether the animals were fed ad libitum, fasted, or treated with triiodothyronine. No phenotypic difference in the in vitro O2 consumption was seen when the muscles were preincubated with or without exogenous insulin. Pyruvate kinase, citrate synthase, succinate dehydrogenase, and cytochrome oxidase activities were similar in the soleus and the EDL muscles of both phenotypes. Phosphofructokinase and lactate dehydrogenase activities were higher in the soleus muscles from the obese rats, whereas hexokinase activities were higher in the EDL muscles from the nonobese rats. Mitochondrial and whole muscle homogenate respiration rates were similar in both phenotypes. The soleus and EDL muscles from the obese animals weighed less than those from the nonobese, but empty carcass weights were similar. Taken together these data suggest that muscle mass, muscle O2 consumption, and muscle oxidative capacity are similar in 6-wk-old obese and nonobese rats. Therefore other tissues are probably responsible for the increased metabolic efficiency of the young obese rat.

Effects of exercise on macrophage activation for antitumor cytotoxicity

1994 ◽  
Vol 76 (5) ◽  
pp. 2177-2185 ◽  
Author(s):  
J. A. Woods ◽  
J. M. Davis ◽  
E. P. Mayer ◽  
A. Ghaffar ◽  
R. R. Pate
Keyword(s):  
Interferon Gamma ◽  
Interleukin 1 ◽  
Plasma Corticosterone ◽  
Peritoneal Macrophages ◽  
Treadmill Running ◽  
Necrosis Factor Alpha ◽  
Macrophage Cytotoxicity ◽  
Exercise Induced

Recent evidence suggests that exercise affects macrophage functions and that amount of exercise may be important. We determined effects of moderate (MOD) and exhaustive treadmill running (EXH) on 1) ability of macrophages to become activated for antitumor cytotoxicity after injection of heat-inactivated Propionibacterium acnes in vivo, 2) macrophage responsiveness to activating agents lipopolysaccharide and interferon-gamma, and 3) role of glucocorticoids and various macrophage metabolic products in modulating cytotoxicity in exercised animals. Male C3H/HeN mice were randomly assigned to MOD (18 m/min, 5% grade, 30 min/day) or EXH (18–35 m/min, 5%, 2–4 h) on a motor-driven treadmill. Control animals were kept in simulated treadmill lanes located directly over the runners. In general, both MOD and EXH increased cytotoxicity (42 and 22%, respectively, across all experiments; P < 0.05). Enhanced cytotoxicity was not due to altered macrophage adherence, tumor necrosis factor-alpha, interleukin-1 beta, or reactive oxygen species. Reactive nitrogen species were responsible for enhanced toxicity in EXH only. Macrophage cytotoxicity was further increased by lipopolysaccharide and interferon-gamma to a similar maximal level that was the same in all groups. Plasma corticosterone was elevated two- and fourfold in MOD and EXH, respectively, but there was no correlation between plasma corticosterone and macrophage cytotoxicity when compared across all groups even though cells were sensitive to steroid-mediated suppression in vitro. However, consistent with a corticosterone effect, EXH reduced the number of peritoneal macrophages elicited during P. acnes inflammation and abolished the typical exercise-induced increase in cytotoxicity of activated macrophages.(ABSTRACT TRUNCATED AT 250 WORDS)

Androgen cytosol binding in exercise-induced sparing of muscle atrophy

1984 ◽  
Vol 247 (5) ◽  
pp. E597-E603
Author(s):  
R. C. Hickson ◽  
T. T. Kurowski ◽  
J. A. Capaccio ◽  
R. T. Chatterton
Keyword(s):  
Muscle Atrophy ◽  
Specific Binding ◽  
Exercise Group ◽  
Treadmill Running ◽  
Female Rats ◽  
Binding Model ◽  
Subcutaneous Injections ◽  
Treatment Groups ◽  
Exercise Induced ◽  
Gastrocnemius Muscles

This study was undertaken to determine whether the exercise-induced sparing of glucocorticoid-induced muscle atrophy is related to increased androgen cytosol binding. Female rats were divided into a sedentary or an exercise group that was trained by treadmill running 100 min/day for 13-15 wk. During the last 12 days of training, each of these groups was further subdivided into groups that received daily subcutaneous injections of cortisone acetate (CA) (100 mg/kg body wt) or the vehicle 1% carboxymethyl cellulose. Exercise prevented 30-40% of the weight loss due to CA treatment in gastrocnemius and plantaris muscles. Scatchard analyses of specific binding of [3H]methyltrienolone (R1881), a synthetic androgen that binds to androgen receptors, were nonlinear in muscles from vehicle-treated sedentary and trained rats and were resolved by a two-component binding model. The lower affinity component, which was attributed to a glucocorticoid receptor, disappeared in muscles of glucocorticoid-treated animals as evidenced by linear Scatchard plots. Receptor concentrations of the androgenic component of [3H]methyltrienolone binding were similar in gastrocnemius and plantaris muscles in all treatment groups. In binding specificity studies of gastrocnemius muscles, the relatively high competition by various glucocorticoids and progesterone for [3H]methyltrienolone binding in the vehicle-treated groups was reduced by CA treatment. The lack of change in androgen cytosol receptor levels suggests that this is not a mechanism by which exercise protects against glucocorticoid-induced muscle atrophy.

scholarly journals Thermal instability of rat muscle sarcoplasmic reticulum Ca2+-ATPase function

2002 ◽  
Vol 283 (4) ◽  
pp. E722-E728 ◽  
Author(s):  
J. D. Schertzer ◽  
H. J. Green ◽  
A. R. Tupling
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Atpase Activity ◽  
Thermal Instability ◽  
Calcium Release ◽  
Calcium Release Channel ◽  
Release Channel ◽  
Adult Rat ◽  
Hill Slope ◽  
Exercise Induced

To examine the thermal instability and the role of sulfhydryl (SH) oxidation on sarcoplasmic reticulum (SR) Ca2+-ATPase function, crude homogenates were prepared from the white portion of the gastrocnemius (WG) adult rat muscles ( n = 9) and incubated in vitro for ≤60 min either at a normal resting body temperature (37°C) or at a temperature indicative of exercise-induced hyperthermia (41°C) with DTT and without DTT (CON). In general, treatment with DTT resulted in higher Ca2+-ATPase and Ca2+ uptake values (nmol · mg protein−1 · min−1, P < 0.05), an effect that was not specific to time of incubation. Incubations at 41°C resulted in lower ( P< 0.05) Ca2+ uptake rates (156 ± 18 and 35.9 ± 3.3) compared with 37°C (570 ± 54 and 364 ± 26) at 30 and 60 min, respectively. At 37°C, ryanodine (300 μM), which was used to block Ca2+ release from the calcium release channel, prevented the time-dependent decrease in Ca2+ uptake. A general inactivation ( P < 0.05) of maximal Ca2+-ATPase activity ( V max) in CON was observed with incubation time (0 > 30 > 60 min), with the effect being more pronounced ( P < 0.05) at 41°C compared with 37°C. The Hill slope, a measure of co-operativity, and the pCa50, the cytosolic Ca2+ concentration required for half-maximal activation of Ca2+-ATPase activity, decreased ( P < 0.05) at 41°C only. Treatment with DTT attenuated the alterations in enzyme kinetics. The increase in V max with the Ca2+ionophore A-23187 was less pronounced at 41°C compared with 37°C. It is concluded that exposure of homogenates to a temperature typically experienced in exercise results in a reduction in the coupling ratio, which is mediated primarily by lower Ca2+ uptake and occurs as a result of increases in membrane permeability to Ca2+. Moreover, the decreases in Ca2+-ATPase kinetics in WG with sustained heat stress result from SH oxidation.

Na+-K+-ATPase in rat skeletal muscle: muscle fiber-specific differences in exercise-induced changes in ion affinity and maximal activity

2009 ◽  
Vol 296 (1) ◽  
pp. R125-R132 ◽  
Author(s):  
Carsten Juel
Keyword(s):  
Skeletal Muscle ◽  
Atpase Activity ◽  
Muscle Fiber ◽  
Muscle Activity ◽  
Fiber Type ◽  
Treadmill Running ◽  
Vitro Activity ◽  
In Vitro Activity ◽  
Rat Skeletal Muscle

It is unclear whether muscle activity reduces or increases Na+-K+-ATPase maximal in vitro activity in rat skeletal muscle, and it is not known whether muscle activity changes the Na+-K+-ATPase ion affinity. The present study uses quantification of ATP hydrolysis to characterize muscle fiber type-specific changes in Na+-K+-ATPase activity in sarcolemmal membranes and in total membranes obtained from control rats and after 30 min of treadmill running. ATPase activity was measured at Na+ concentrations of 0–80 mM and K+ concentrations of 0–10 mM. Km and Vmax values were obtained from a Hill plot. Km for Na+ was higher (lower affinity) in total membranes of glycolytic muscle (extensor digitorum longus and white vastus lateralis), when compared with oxidative muscle (red gastrocnemius and soleus). Treadmill running induced a significant decrease in Km for Na+ in total membranes of glycolytic muscle, which abolished the fiber-type difference in Na+ affinity. Km for K+ (in the presence of Na+) was not influenced by running. Running only increased the maximal in vitro activity ( Vmax) in total membranes from soleus, whereas Vmax remained constant in the three other muscles tested. In conclusion, muscle activity induces fiber type-specific changes both in Na+ affinity and maximal in vitro activity of the Na+-K+-ATPase. The underlying mechanisms may involve translocation of subunits and increased association between PLM units and the αβ complex. The changes in Na+-K+-ATPase ion affinity are expected to influence muscle ion balance during muscle contraction.

Skeletal muscle respiratory capacity, endurance, and glycogen utilization

1975 ◽  
Vol 228 (4) ◽  
pp. 1029-1033 ◽  
Author(s):  
RH Fitts ◽  
FW Booth ◽  
WW Winder ◽  
JO Holloszy
Keyword(s):  
Skeletal Muscle ◽  
Citrate Synthase ◽  
Treadmill Running ◽  
Mitochondrial Content ◽  
Respiratory Capacity ◽  
Leg Muscles ◽  
Glycogen Utilization ◽  
Exercise Induced ◽  
Gastrocnemius Muscles ◽  
The Relationship

This study was undertaken to evaluate the relationship between physical performance capacity and the mitochondrial content of skeletal muscle. Four groups of rats were trained by means of treadmill running 5 days/wk for 13 wk. One group ran 10 min/day, a second group ran 30 min/day, a third group ran 60 min/day, and a fourth group ran 120 min/day. The magnitude of the exercise-induced adaptive increase in gastrocnemius muscle respiratory capacity varied over a twofold range in the four groups. There were significant correlations between the levels of three mitochondrial markers (cytochrome c, citrate synthase, respiratory capacity) in the animals' gastrocnemius muscles and the duration of a run to exhaustion. There was also a significant correlation between the amounts of glycogen remaining in liver and skeletal muscle after a 30-min-long exercise test and the respiratory capacity of the animal's leg muscles. These findings are compatible with the interpretation that a close relationshiop exists between skeletal muscle mitochondrial content and the capacity to perform endurance exercise.

Recent Patents on Anti-Cancer Potential of Helenalin

2020 ◽  
Vol 15 (2) ◽  
pp. 132-142
Author(s):  
Priyanka Kriplani ◽  
Kumar Guarve
Keyword(s):  
Synergistic Effects ◽  
Therapeutic Interventions ◽  
Active Constituent ◽  
Scientific Impact ◽  
Isolation Techniques ◽  
Anti Cancer ◽  
Prevention Of Cancer ◽  
Synthetic Derivatives

Background: Arnica montana, containing helenalin as its principal active constituent, is the most widely used plant to treat various ailments. Recent studies indicate that Arnica and helenalin provide significant health benefits, including anti-inflammatory, neuroprotective, antioxidant, cholesterol-lowering, immunomodulatory, and most important, anti-cancer properties. Objective: The objective of the present study is to overview the recent patents of Arnica and its principal constituent helenalin, including new methods of isolation, and their use in the prevention of cancer and other ailments. Methods: Current prose and patents emphasizing the anti-cancer potential of helenalin and Arnica, incorporated as anti-inflammary agents in anti-cancer preparations, have been identified and reviewed with particular emphasis on their scientific impact and novelty. Results: Helenalin has shown its anti-cancer potential to treat multiple types of tumors, both in vitro and in vivo. It has also portrayed synergistic effects when given in combination with other anti- cancer drugs or natural compounds. New purification/isolation techniques are also developing with novel helenalin formulations and its synthetic derivatives have been developed to increase its solubility and bioavailability. Conclusion: The promising anti-cancer potential of helenalin in various preclinical studies may open new avenues for therapeutic interventions in different tumors. Thus clinical trials validating its tumor suppressing and chemopreventive activities, particularly in conjunction with standard therapies, are immediately required.

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