scholarly journals Increases in skeletal muscle ATGL and its inhibitor G0S2 following 8 weeks of endurance training in metabolically different rat skeletal muscles

2016 ◽  
Vol 310 (2) ◽  
pp. R125-R133 ◽  
Author(s):  
Patrick C. Turnbull ◽  
Amanda B. Longo ◽  
Sofhia V. Ramos ◽  
Brian D. Roy ◽  
Wendy E. Ward ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Endurance Training ◽  
Skeletal Muscles ◽  
Gene Identification ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Hind Limb Muscle ◽  
Sciatic Nerve Stimulation ◽  
Rate Limiting

Adipose triglyceride lipase (ATGL) catalyzes the rate-limiting removal of the first fatty acid from a triglyceride. ATGL is activated by comparative gene identification-58 and inhibited by G(0)/G(1) switch gene-2 protein (G0S2). Research in other tissues and cell culture indicates that inhibition is dependent on relative G0S2-to-ATGL protein content. G0S2 may also have several roles within mitochondria; however, this has yet to be observed in skeletal muscle. The purpose of this study was to determine if muscle G0S2 relative to ATGL content would decrease to facilitate intramuscular lipolysis following endurance training. Male Sprague-Dawley rats ( n = 10; age 51–53 days old) were progressively treadmill trained at a 10% incline for 8 wk ending with 25 m/min for 1 h compared with control. Sciatic nerve stimulation for hind-limb muscle contraction (and lipolysis) was administered for 30 min to one leg, leaving the opposing leg as a resting control. Soleus (SOL), red gastrocnemius (RG), and white gastrocnemius were excised from both legs following stimulation or control. ATGL protein increased in all trained muscles. Unexpectedly, G0S2 protein was greater in the trained SOL and RG. In RG-isolated mitochondria, G0S2 also increased with training, yet mitochondrial G0S2 content was unaltered with acute contraction; therefore, any role of G0S2 in the mitochondria does not appear to be acutely mediated by content alone. In summary, G0S2 increased with training in oxidative muscles and mitochondria but not following acute contraction, suggesting that inhibition is not through relative G0S2-to-ATGL content but through more complicated intracellular mechanisms.

scholarly journals Mild DOCA-salt hypertension: sympathetic system and role of renal nerves

2011 ◽  
Vol 300 (5) ◽  
pp. H1781-H1787 ◽  
Author(s):  
Sachin S. Kandlikar ◽  
Gregory D. Fink
Keyword(s):  
Control Period ◽  
Whole Body ◽  
Renal Nerves ◽  
Experimental Hypertension ◽  
Sympathetic Activation ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Salt Hypertension ◽  
Hypertension Development

Excess sympathetic nervous system activity (SNA) is linked to human essential and experimental hypertension. To test whether sympathetic activation is associated with a model of deoxycorticosterone acetate (DOCA)-salt hypertension featuring two kidneys and a moderate elevation of blood pressure, we measured whole body norepinephrine (NE) spillover as an index of global SNA. Studies were conducted in chronically catheterized male Sprague-Dawley rats drinking water containing 1% NaCl and 0.2% KCl. After a 7-day surgical recovery and a 3-day control period, a DOCA pellet (50 mg/kg) was implanted subcutaneously in one group of rats (DOCA), while the other group underwent sham implantation (Sham). NE spillover was measured on control day 2 and days 7 and 14 after DOCA administration or sham implantation. During the control period, mean arterial pressure (MAP) was similar in Sham and DOCA rats. MAP was significantly increased in the DOCA group compared with the Sham group after DOCA administration ( day 14: Sham = 109 ± 5.3, DOCA = 128 ± 3.6 mmHg). However, plasma NE concentration, clearance, and spillover were not different in the two groups at any time. To determine whether selective sympathetic activation to the kidneys contributes to hypertension development, additional studies were performed in renal denervated (RDX) and sham-denervated (Sham-DX) rats. MAP, measured by radiotelemetry, was similar in both groups during the control and DOCA treatment periods. In conclusion, global SNA is not increased during the development of mild DOCA-salt hypertension, and fully intact renal nerves are not essential for hypertension development in this model.

Chronic intravenous administration of V1 arginine vasopressin agonist results in sustained hypertension

1994 ◽  
Vol 267 (2) ◽  
pp. H751-H756 ◽  
Author(s):  
A. W. Cowley ◽  
E. Szczepanska-Sadowska ◽  
K. Stepniakowski ◽  
D. Mattson
Keyword(s):  
Body Weight ◽  
Arginine Vasopressin ◽  
Plasma Catecholamines ◽  
Plasma Osmolality ◽  
Sprague Dawley ◽  
Prolonged Administration ◽  
Chronic Stimulation ◽  
Sustained Hypertension ◽  
Sprague Dawley Rats

Despite the well-recognized vasoconstrictor and fluid-retaining actions of vasopressin, prolonged administration of arginine vasopressin (AVP) to normal animals or humans fails to produce sustained hypertension. The present study was performed to elucidate the role of the V1 receptor in determining the ability of AVP to produce sustained hypertension. Conscious Sprague-Dawley rats with implanted catheters were infused with the selective V1 agonist, [Phe2,Ile3,Orn8]vasopressin (2 ng.kg-1.min-1), for 14 days in amounts that were acutely nonpressor. Blood pressure (MAP), heart rate (HR), body weight, and water intake (WI) were determined daily. Plasma AVP, plasma catecholamines norepinephrine and epinephrine, plasma osmolality, and electrolyte concentration were determined before and on days 1 and 7 of infusion. MAP increased significantly by 10.4 +/- 4.5 mmHg on day 1 and rose to 22 +/- 5 mmHg above control by day 14 (transient decrease on days 6-9) and then fell to control levels after the infusion was stopped. HR did not change significantly. Plasma AVP immunoreactivity increased from 2.5 +/- 0.3 to 10.9 +/- 2.1 pg/ml, whereas norepinephrine tended to fall only on day 1, with epinephrine only slightly elevated on day 7. No evidence of fluid retention was found, and rats lost sodium only on the first day of V1 agonist infusion. Body weight increased throughout the study but was unrelated to the changes of MAP. We conclude that chronic stimulation of V1 receptors results in sustained hypertension in rats.

HIF-1α in endurance training: suppression of oxidative metabolism

2007 ◽  
Vol 293 (5) ◽  
pp. R2059-R2069 ◽  
Author(s):  
Steven D. Mason ◽  
Helene Rundqvist ◽  
Ioanna Papandreou ◽  
Roger Duh ◽  
Wayne J. McNulty ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Endurance Training ◽  
Oxidative Metabolism ◽  
Hypoxia Inducible Factor ◽  
Transcriptional Response ◽  
Oxidative Capacity ◽  
Pyruvate Dehydrogenase Kinase ◽  
Amp Activated Protein Kinase ◽  
Training Protocol

During endurance training, exercising skeletal muscle experiences severe and repetitive oxygen stress. The primary transcriptional response factor for acclimation to hypoxic stress is hypoxia-inducible factor-1α (HIF-1α), which upregulates glycolysis and angiogenesis in response to low levels of tissue oxygenation. To examine the role of HIF-1α in endurance training, we have created mice specifically lacking skeletal muscle HIF-1α and subjected them to an endurance training protocol. We found that only wild-type mice improve their oxidative capacity, as measured by the respiratory exchange ratio; surprisingly, we found that HIF-1α null mice have already upregulated this parameter without training. Furthermore, untrained HIF-1α null mice have an increased capillary to fiber ratio and elevated oxidative enzyme activities. These changes correlate with constitutively activated AMP-activated protein kinase in the HIF-1α null muscles. Additionally, HIF-1α null muscles have decreased expression of pyruvate dehydrogenase kinase I, a HIF-1α target that inhibits oxidative metabolism. These data demonstrate that removal of HIF-1α causes an adaptive response in skeletal muscle akin to endurance training and provides evidence for the suppression of mitochondrial biogenesis by HIF-1α in normal tissue.

The Hepatoprotective Role of Warburgia salutaris and Iso-Mukaadial Acetate on Carbon tetrachloride Intoxicated Rats Model

2021 ◽  
Vol 17 ◽  
Author(s):  
Gideon Ayeni ◽  
Mthokozisi Blessing Cedric Simelane ◽  
Shahidul Islam ◽  
Ofentse Jacob Pooe
Keyword(s):  
Carbon Tetrachloride ◽  
Hepatic Injury ◽  
Antioxidant Properties ◽  
Hepatic Necrosis ◽  
Protective Role ◽  
Dependent Manner ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Isolated Compound

Background: Medicinal plants together with their isolated bioactive compounds are known for their antioxidant properties which constitute therapeutic agents that are routinely employed in the treatment of liver diseases. Aims of the Study: The current study sought to explore the protective role of Warburgia salutaris and its isolated compound, iso-mukaadial acetate against carbon tetrachloride (CCl4)-induced hepatic injury. Methods: Thirty-five male Sprague Dawley rats were divided into seven groups of five animals each and injected with CCl4 to induce hepatic injury. Results: Treatment with the crude extract of W. salutaris and of iso-mukaadial acetate significantly reduced the levels of alkaline phosphatase, alanine and aspartate aminotransaminases, total bilirubin and malondialdehyde in a dose dependent manner, when compared to untreated groups. Liver histology revealed a reduction in hepatic necrosis and inflammation. Conclusion: The current investigation has demonstrated that W. salutaris extract and iso-mukaadial acetate could mitigate the acute liver injury inflicted by a hepatotoxic inducer in rats.

scholarly journals Transient Neonatal Cryptosporidium parvum Infection Triggers Long-Term Jejunal Hypersensitivity to Distension in Immunocompetent Rats

2006 ◽  
Vol 74 (7) ◽  
pp. 4387-4389 ◽  
Author(s):  
Rachel Marion ◽  
Asiya Baishanbo ◽  
Gilles Gargala ◽  
Arnaud François ◽  
Philippe Ducrotté ◽  
...  
Keyword(s):  
Cryptosporidium Parvum ◽  
Myeloperoxidase Activity ◽  
Sprague Dawley ◽  
Depressor Response ◽  
Sprague Dawley Rats

ABSTRACT In 5-day-old immunocompetent Sprague-Dawley rats infected with either 102 or 105 Cryptosporidium parvum oocysts, transient infection resulted 120 days later in increased cardiovascular depressor response to jejunal distension and jejunal myeloperoxidase activity (P < 0.05). Nitazoxanide treatment normalized jejunal sensitivity (P < 0.001) but not myeloperoxidase levels (P > 0.05). Data warrant further evaluation of the role of early cryptosporidiosis in the development of chronic inflammatory gut conditions.

scholarly journals The Role of Eif6 in Skeletal Muscle Homeostasis Revealed by Endurance Training Co-expression Networks

Cell Reports ◽  
2017 ◽  
Vol 21 (6) ◽  
pp. 1507-1520 ◽  
Author(s):  
Kim Clarke ◽  
Sara Ricciardi ◽  
Tim Pearson ◽  
Izwan Bharudin ◽  
Peter K. Davidsen ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Endurance Training ◽  
Muscle Homeostasis
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