Ammonium Chloride Ingestion Attenuates Exercise-Induced mRNA Levels in Human Muscle

Introduction: There is emerging evidence in men that sustained high-intensity training promotes an adverse cardiovascular remodeling, thereby increasing the risk of atrial fibrillation, ventricular arrhythmias and coronary calcification. Whether men and women are similarly affected by high intensity exercise-induced harm is unclear. Our aim was to study sex differences in a long-term endurance training rat model. Methods: Male and female Wistar rats were subjected to high intensity training for 16 weeks (INT, 60min 60cm/s, male n=20, female n=15). Sedentary rats (SED, male n=20, female n=18) were used as controls. At the end of the training period, rats had an electrocardiogram and echocardiography performed. Vascular fibrosis was assessed in descending aorta, left carotid, and intramyocardial arteries (IMA), right and left atria, and left ventricle (LV) histological samples. mRNA levels of cardiac hypertrophy, fibrosis, oxidative stress and inflammation genes were assessed in LV samples by Real-Time PCR. Results: INT male rats presented lower heart rate (382±9, 340±10, SED vs INT, p<0.01) and a longer QRS duration (18.8±0.6, 22.4±1.1, SED vs INT, p<0.01), while these were not modified in the INT female group. Echocardiography showed eccentric LV hypertrophy in both trained male and female rats. High intensity exercise induced fibrosis in the descending aorta and carotid in both males and females, but IMA were only affected in trained male rats. In the heart, exercise-induced atrial fibrosis similarly occurred in both trained male and female rats. No training-induced fibrosis was evident in the LV of both INT male and female rats. Regarding LV mRNA analysis, INT males showed a reduction of desmin, TTN and N2BA/N2B ratio, whereas INT females exhibited higher desmin mRNA levels and lower αMHC/βMHC ratio. Intense exercise did not increase LV mRNA levels of fibrosis, oxidative stress and inflammation markers neither in males nor in females. In comparison to males, females had lower LV myocardial fibrosis as well as lower fibrosis markers. Conclusions: Male and female rats exhibit qualitatively different cardiovascular remodeling after extreme exercise. Nevertheless, both sexes might develop exercise-induced adverse vascular and cardiac effects.

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Exercise-induced changes in β-adrenergic-receptor mRNA level measured by competitive RT-PCR

Journal of Applied Physiology ◽

10.1152/jappl.1997.82.6.1926 ◽

1997 ◽

Vol 82 (6) ◽

pp. 1926-1931 ◽

Cited By ~ 4

Author(s):

Nobuharu Fujii ◽

Takeshi Shibata ◽

Sachiko Homma ◽

Haruo Ikegami ◽

Kazuo Murakami ◽

...

Keyword(s):

Adrenergic Receptor ◽

Human Lymphocytes ◽

Mrna Level ◽

Mrna Levels ◽

Rt Pcr ◽

Receptor Mrna ◽

Exercise Induced ◽

Induced Changes ◽

Receptor Mrna Level

Fujii, Nobuharu, Takeshi Shibata, Sachiko Homma, Haruo Ikegami, Kazuo Murakami, and Hitoshi Miyazaki. Exercise-induced changes in β-adrenergic-receptor mRNA level measured by competitive RT-PCR. J. Appl. Physiol. 82(6): 1926–1931, 1997.—Competitive reverse transcription-polymerase chain reaction (RT-PCR) analysis was used to clarify whether dynamic exercise-induced increases in β-adrenergic-receptor (β-AR) number in human lymphocytes are accompanied by increases in the β-AR mRNA level. Sixteen healthy subjects performed cycle ergometry until exhaustion. Before and immediately after exercise, peripheral blood was drawn from a forearm vein for preparation of lymphocytes. Both the β-AR mRNA level and the β-AR number were significantly increased by exercise. The changes in β-AR mRNA level and β-AR number were significantly correlated ( r = 0.63, P < 0.01). This finding suggests that a rapid increase in β-AR mRNA level might be an early adaptive response of the sympathetic nervous system to dynamic exercise. In vitro incubation of lymphocytes with epinephrine had no effect on β-AR mRNA levels, nor did adenosine 3′,5′-cyclic monophosphate, protein kinase C, or intracellular Ca2+ increase the β-AR mRNA level in vitro. Therefore, it appears that other mechanisms underlie the exercise-induced elevation of β-AR mRNA levels in human lymphocytes.

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Effect of carbohydrate ingestion on exercise-induced alterations in metabolic gene expression

Journal of Applied Physiology ◽

10.1152/japplphysiol.00197.2005 ◽

2005 ◽

Vol 99 (4) ◽

pp. 1359-1363 ◽

Cited By ~ 66

Author(s):

Laura J. Cluberton ◽

Sean L. McGee ◽

Robyn M. Murphy ◽

Mark Hargreaves

Keyword(s):

Gene Expression ◽

Oxygen Uptake ◽

Pyruvate Dehydrogenase Kinase ◽

Mrna Levels ◽

Carbohydrate Ingestion ◽

Pulmonary Oxygen Uptake ◽

Metabolic Gene ◽

Metabolic Gene Expression ◽

Glucose Ingestion ◽

Exercise Induced

Skeletal muscle possesses a high degree of plasticity and can adapt to both the physical and metabolic challenges that it faces. An acute bout of exercise is sufficient to induce the expression of a variety of metabolic genes, such as GLUT4, pyruvate dehydrogenase kinase 4 (PDK-4), uncoupling protein-3 (UCP3), and peroxisome proliferator-activated receptor-γ coactivator 1 (PGC-1). Reducing muscle glycogen levels before exercise potentiates the effect of exercise on many genes. Similarly, altered substrate availability induces transcription of many of these genes. The purpose of this study was to determine whether glucose ingestion attenuates the exercise-induced increase in a variety of exercise-responsive genes. Six male subjects (28 ± 7 yr; 83 ± 3 kg; peak pulmonary oxygen uptake = 46 ± 6 ml·kg−1·min−1) performed 60 min of cycling at 74 ± 2% of peak pulmonary oxygen uptake on two separate occasions. On one occasion, subjects ingested a 6% carbohydrate drink. On the other occasion, subjects ingested an equal volume of a sweet placebo. Muscle samples were obtained from vastus lateralis at rest, immediately after exercise, and 3 h after exercise. PDK-4, UCP3, PGC-1, and GLUT4 mRNA levels were measured on these samples using real-time RT-PCR. Glucose ingestion attenuated ( P < 0.05) the exercise-induced increase in PDK-4 and UCP3 mRNA. A similar trend ( P = 0.09) was observed for GLUT4 mRNA. In contrast, PGC-1 mRNA increased following exercise to the same extent in both conditions. These data suggest that glucose availability can modulate the effect of exercise on metabolic gene expression.

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Exercise enhances myocardial ischemic tolerance via an opioid receptor-dependent mechanism

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00280.2007 ◽

2008 ◽

Vol 294 (1) ◽

pp. H402-H408 ◽

Cited By ~ 42

Author(s):

Eric W. Dickson ◽

Christopher P. Hogrefe ◽

Paula S. Ludwig ◽

Laynez W. Ackermann ◽

Lynn L. Stoll ◽

...

Keyword(s):

Infarct Size ◽

Opioid Receptor ◽

Cardiovascular Health ◽

Ischemic Tolerance ◽

Control Group ◽

Mrna Levels ◽

Standard Protocol ◽

Vigorous Exercise ◽

Cardioprotective Effects ◽

Exercise Induced

Exercise increases serum opioid levels and improves cardiovascular health. Here we tested the hypothesis that opioids contribute to the acute cardioprotective effects of exercise using a rat model of exercise-induced cardioprotection. For the standard protocol, rats were randomized to 4 days of treadmill training and 1 day of vigorous exercise ( day 5), or to a sham exercise control group. On day 6, animals were killed, and global myocardial ischemic tolerance was assessed on a modified Langendorff apparatus. Twenty minutes of ischemia followed by 3 h of reperfusion resulted in a mean infarct size of 42 ± 4% in hearts from sham exercise controls and 21 ± 3% ( P < 0.001) in the exercised group. The cardioprotective effects of exercise were gone by 5 days after the final exercise period. To determine the role of opioid receptors in exercise-induced cardioprotection, rats were exercised according to the standard protocol; however, just before exercise on days 4 and 5, rats were injected subcutaneously with 10 mg/kg of the opioid receptor antagonist naltrexone. Similar injections were performed in the sham exercise control group. Naltrexone had no significant effect on baseline myocardial ischemic tolerance in controls (infarct size 43 ± 4%). In contrast, naltrexone treatment completely blocked the cardioprotective effect of exercise (infarct size 40 ± 5%). Exercise was also associated with an early increase in myocardial mRNA levels for several opioid system genes and with sustained changes in a number of genes that regulate inflammation and apoptosis. These findings demonstrate that the acute cardioprotective effects of exercise are mediated, at least in part, through opioid receptor-dependent mechanisms that may include changes in gene expression.

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Time Course for Refilling of Glycogen Stores in Human Muscle Fibres Following Exercise-Induced Glycogen Depletion

Acta Physiologica Scandinavica ◽

10.1111/j.1748-1716.1974.tb05592.x ◽

1974 ◽

Vol 90 (2) ◽

pp. 297-302 ◽

Cited By ~ 81

Author(s):

Karin Piehl

Keyword(s):

Time Course ◽

Human Muscle ◽

Muscle Fibres ◽

Glycogen Depletion ◽

Exercise Induced ◽

Glycogen Stores

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Muscle microvascular adaptation and angiogenic gene induction in response to exercise training are attenuated in middle-aged rats

Comparative Exercise Physiology ◽

10.3920/cep150007 ◽

2015 ◽

Vol 11 (1) ◽

pp. 23-33

Author(s):

J. Suzuki

Keyword(s):

Exercise Training ◽

Acute Exercise ◽

Young Group ◽

Treadmill Running ◽

Mrna Levels ◽

Aged Rats ◽

Middle Aged ◽

Vegf Mrna ◽

Aged Group ◽

Exercise Induced

This study was designed to investigate exercise-induced changes in muscle capillarisation, the mRNA expression of angiogenic genes, and microRNA levels in young and middle-aged rats. Rats in the training groups were subjected to treadmill running 5 days a week for 3 weeks. The exercise protocol for the young (12-week old) group was 20-25 m/min, 40-60 min/day with a gradient of 15%, and for the middle-aged (12-month old) group was 18-20 m/min, 40-60 min/day with a gradient of 5%. The enzyme histochemical identification of capillary profiles was performed on cross-sections of gastrocnemius muscle. Total RNA was isolated, reverse transcription was performed, and mRNA and microRNA levels were determined by real-time PCR. The capillary-to-fibre ratio was significantly increased by exercise training in the young group (by 10%), but only slightly in the middle-aged (by 5%) group. Vascular endothecial growth factor (VEGF) mRNA levels were at significantly higher values after acute exercise (1.6-fold) and the 3-week training protocol (1.9-fold) in the young group, but not in the middle-aged group. VEGF protein expression levels were significantly increased after training in the young group only. Endothelial nitric oxide synthase, VEGF-R2 and thrombospondin-1 mRNA levels were significantly lower in the middle-aged group than in the young group. Anti-angiogenic miR-195 levels were significantly enhanced by exercise training in the middle-aged group only. These results indicated that the exercise-induced adaptation of muscle capillarity was attenuated in middle-aged rats, possibly by the lower induction of VEGF and up-regulation of anti-angiogenic miRNA expression.

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Combined speed endurance and endurance exercise amplify the exercise-induced PGC-1α and PDK4 mRNA response in trained human muscle

Physiological Reports ◽

10.14814/phy2.12864 ◽

2016 ◽

Vol 4 (14) ◽

pp. e12864 ◽

Cited By ~ 18

Author(s):

Casper Skovgaard ◽

Nina Brandt ◽

Henriette Pilegaard ◽

Jens Bangsbo

Keyword(s):

Endurance Exercise ◽

Human Muscle ◽

Exercise Induced

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Exercise-induced activation of the branched-chain 2-oxo acid dehydrogenase in human muscle

European Journal of Applied Physiology and Occupational Physiology ◽

10.1007/bf02386181 ◽

1989 ◽

Vol 59 (3) ◽

pp. 159-167 ◽

Cited By ~ 81

Author(s):

Anton J. M. Wagenmakers ◽

John H. Brookes ◽

John H. Coakley ◽

Thomas Reilly ◽

Richard H. T. Edwards

Keyword(s):

Human Muscle ◽

Acid Dehydrogenase ◽

Branched Chain ◽

Exercise Induced

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Effect of acute exercise and exercise training on VEGF splice variants in human skeletal muscle

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00071.2004 ◽

2004 ◽

Vol 287 (2) ◽

pp. R397-R402 ◽

Cited By ~ 45

Author(s):

Lotte Jensen ◽

Henriette Pilegaard ◽

P. Darrell Neufer ◽

Ylva Hellsten

Keyword(s):

Skeletal Muscle ◽

Exercise Training ◽

Human Skeletal Muscle ◽

Acute Exercise ◽

Splice Variants ◽

Knee Extensor ◽

Vastus Lateralis Muscle ◽

Mrna Levels ◽

Vegf Mrna ◽

Exercise Induced

The present study investigated the effect of an acute exercise bout on the mRNA response of vascular endothelial growth factor (VEGF) splice variants in untrained and trained human skeletal muscle. Seven habitually active young men performed one-legged knee-extensor exercise training at an intensity corresponding to ∼70% of the maximal workload in an incremental test five times/week for 4 wk. Biopsies were obtained from the vastus lateralis muscle of the trained and untrained leg 40 h after the last training session. The subjects then performed 3 h of two-legged knee-extensor exercise, and biopsies were obtained from both legs after 0, 2, 6, and 24 h of recovery. Real-time PCR was used to examine the expression of VEGF mRNA containing exon 1 and 2 (all VEGF isoforms), exon 6 or exon 7, and VEGF165mRNA. Acute exercise induced an increase ( P < 0.05) in total VEGF mRNA levels as well as VEGF165and VEGF splice variants containing exon 7 at 0, 2, and 6 h of recovery. The increase in VEGF mRNA was higher in the untrained than in the trained leg ( P < 0.05). The results suggest that in human skeletal muscle, acute exercise increases total VEGF mRNA, an increase that appears to be explained mainly by an increase in VEGF165mRNA. Furthermore, 4 wk of training attenuated the exercise-induced response in skeletal muscle VEGF165mRNA.

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Effect of nitric oxide synthase inhibition on mitochondrial biogenesis in rat skeletal muscle

Journal of Applied Physiology ◽

10.1152/japplphysiol.00549.2006 ◽

2007 ◽

Vol 102 (1) ◽

pp. 314-320 ◽

Cited By ~ 50

Author(s):

G. D. Wadley ◽

G. K. McConell

Keyword(s):

Nitric Oxide ◽

Skeletal Muscle ◽

Mitochondrial Biogenesis ◽

Acute Exercise ◽

Peroxisome Proliferator ◽

Mrna Levels ◽

Peroxisome Proliferator Activated Receptor ◽

Exercise Induced ◽

Edl Muscle ◽

Oxide Synthase

The purpose of this study was to determine whether nitric oxide synthase (NOS) inhibition decreased basal and exercise-induced skeletal muscle mitochondrial biogenesis. Male Sprague-Dawley rats were assigned to one of four treatment groups: NOS inhibitor NG-nitro-l-arginine methyl ester (l-NAME, ingested for 2 days in drinking water, 1 mg/ml) followed by acute exercise, no l-NAME ingestion and acute exercise, rest plus l-NAME, and rest without l-NAME. The exercised rats ran on a treadmill for 53 ± 2 min and were then killed 4 h later. NOS inhibition significantly ( P < 0.05; main effect) decreased basal peroxisome proliferator-activated receptor-γ coactivator 1β (PGC-1β) mRNA levels and tended ( P = 0.08) to decrease mtTFA mRNA levels in the soleus, but not the extensor digitorum longus (EDL) muscle. This coincided with significantly reduced basal levels of cytochrome c oxidase (COX) I and COX IV mRNA, COX IV protein and COX enzyme activity following NOS inhibition in the soleus, but not the EDL muscle. NOS inhibition had no effect on citrate synthase or β-hydroxyacyl CoA dehydrogenase activity, or cytochrome c protein abundance in the soleus or EDL. NOS inhibition did not reduce the exercise-induced increase in peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α) mRNA in the soleus or EDL. In conclusion, inhibition of NOS appears to decrease some aspects of the mitochondrial respiratory chain in the soleus under basal conditions, but does not attenuate exercise-induced mitochondrial biogenesis in the soleus or in the EDL.

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