Effects of chronic AICAR administration on the metabolic and contractile phenotypes of rat slow- and fast-twitch skeletal muscles

2003 ◽  
Vol 81 (11) ◽  
pp. 1072-1082 ◽  
Author(s):  
Jeremy A Bamford ◽  
Gary D Lopaschuk ◽  
Ian M MacLean ◽  
Marcia L Reinhart ◽  
Walter T Dixon ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Oxidative Capacity ◽  
Medial Gastrocnemius ◽  
Rt Pcr ◽  
Slow Twitch ◽  
Chronic Activation ◽  
Amp Activated Protein Kinase ◽  
Fast Twitch

The present study examined the effects of chronic activation of 5'-AMP-activated protein kinase (AMPK) on the oxidative capacity and myosin heavy chain (MHC) based fibre phenotype of rodent fast- and slow-twitch muscles. Sprague–Dawley rats received daily injections for 4 weeks of the known AMPK activator 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR) or vehicle (control). The AICAR group displayed increases in hexokinase-II (HXK-II) activity, expression, and phosphorylation in fast-twitch muscles (P < 0.001) but not in the slow-twitch soleus (SOL). In the AICAR group, citrate synthase (EC 4.1.3.7) and 3-hydroxyacyl-CoA-dehydrogenase (EC 1.1.1.35) were elevated 1.6- and 2.1-fold (P < 0.05), respectively, in fast-twitch medial gastrocnemius (MG), and by 1.2- and 1.4-fold (P < 0.05) in the slower-twitch plantaris (PLANT). No changes were observed in the slow-twitch SOL. In contrast, the activity of glyceraldehyde phosphate dehydrogenase (EC 1.2.1.12) remained unchanged in all muscles. AICAR treatment did not alter the MHC-based fibre type composition in fast- or slow-twitch muscles, as determined by immunohistochemical and electrophoretic analytical methods or by RT–PCR. We conclude that chronic activation of AMPK mimics the metabolic changes associated with chronic exercise training (increased oxidative capacity) in the fast-twitch MG and PLANT, but does not coordinately alter MHC isoform content or mRNA expression.Key words: AMP-activated protein kinase, myosin heavy chain, metabolism, RT–PCR, SDS–PAGE.

Chronic activation of 5'-AMP-activated protein kinase changes myosin heavy chain expression in growing pigs

2009 ◽  
Vol 87 (10) ◽  
pp. 3124-3133 ◽  
Author(s):  
S. K. Park ◽  
T. L. Sheffler ◽  
M. E. Spurlock ◽  
A. L. Grant ◽  
D. E. Gerrard
Keyword(s):  
Protein Kinase ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Growing Pigs ◽  
Chronic Activation ◽  
Amp Activated Protein Kinase

scholarly journals Effect of thyroid hormone on the myosin heavy chain isoforms in slow and fast muscles of the rat.

1999 ◽  
Vol 46 (3) ◽  
pp. 823-835 ◽  
Author(s):  
A Jakubiec-Puka ◽  
I Ciechomska ◽  
U Mackiewicz ◽  
J Langford ◽  
H Chomontowska
Keyword(s):  
Thyroid Hormone ◽  
Myosin Heavy Chain ◽  
Soleus Muscle ◽  
Heavy Chain ◽  
Myosin Heavy Chain Isoforms ◽  
Leg Muscles ◽  
Slow Twitch ◽  
Fast Twitch ◽  
Fast Muscles ◽  
Slow And Fast Muscles

The myosin heavy chain (MHC) was studied by biochemical methods in the slow-twitch (soleus) and two fast-twitch leg muscles of the triiodothyronine treated (hyperthyroid), thyroidectomized (hypothyroid) and euthyroid (control) rats. The changes in the contents of individual MHC isoforms(MHC-1, MHC-2A, MHC-2B and MHC-2X) were evaluated in relation to the muscle mass and the total MHC content. The MHC-1 content decreased in hyperthyreosis, while it increased in hypothyreosis in the soleus and in the fast muscles. The MHC-2A content increased in hyperthyreosis and it decreased in hypothyreosis in the soleus muscle. In the fast muscles hyperthyreosis did not affect the MHC-2A content, whereas hypothyreosis caused an increase in this MHC isoform content. The MHC-2X, present only in traces or undetected in the control soleus muscle, was synthesised in considerable amount in hyperthyreosis; in hypothyreosis the MHC-2X was not detected in the soleus. In the fast muscles the content of MHC-2X was not affected by any changes in the thyroid hormone level. The MHC-2B seemed to be not influenced by hyperthyreosis in the fast muscles, whereas the hypothyreosis caused a decrease of its content. In the soleus muscle the MHC-2B was not detected in any groups of rats. The results suggest that the amount of each of the four MHC isoforms expressed in the mature rat leg muscles is influenced by the thyroid hormone in a different way. The MHC-2A and the MHC-2X are differently regulated in the soleus and in the fast muscles; thyroid hormone seems to be necessary for expression of those isoforms in the soleus muscle.

scholarly journals Minocycline Treatment Reduces Mass and Force Output From Fast-Twitch Mouse Muscles and Inhibits Myosin Production in C2C12 Myotubes

2021 ◽  
Vol 12 ◽  
Author(s):  
Leonit Kiriaev ◽  
Ben D. Perry ◽  
David A. Mahns ◽  
Peter J. Shortland ◽  
Asma Redwan ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Cultured Cells ◽  
Force Production ◽  
Independent Effect ◽  
C2c12 Myotubes ◽  
Minocycline Treatment ◽  
Slow Twitch ◽  
Fast Twitch

Minocycline, a tetracycline-class of antibiotic, has been tested with mixed effectiveness on neuromuscular disorders such as amyotrophic lateral sclerosis, autoimmune neuritis and muscular dystrophy. The independent effect of minocycline on skeletal muscle force production and signalling remain poorly understood. Our aim here is to investigate the effects of minocycline on muscle mass, force production, myosin heavy chain abundance and protein synthesis. Mice were injected with minocycline (40 mg/kg i.p.) daily for 5 days and sacrificed at day six. Fast-twitch EDL, TA muscles and slow-twitch soleus muscles were dissected out, the TA muscle was snap-frozen and the remaining muscles were attached to force transducer whilst maintained in an organ bath. In C2C12 myotubes, minocycline was applied to the media at a final concentration of 10 μg/mL for 48 h. In minocycline treated mice absolute maximal force was lower in fast-twitch EDL while in slow-twitch soleus there was an increase in the time to peak and relaxation of the twitch. There was no effect of minocycline treatment on the other contractile parameters measured in isolated fast- and slow-twitch muscles. In C2C12 cultured cells, minocycline treatment significantly reduced both myosin heavy chain content and protein synthesis without visible changes to myotube morphology. In the TA muscle there was no significant changes in myosin heavy chain content. These results indicate that high dose minocycline treatment can cause a reduction in maximal isometric force production and mass in fast-twitch EDL and impair protein synthesis during myogenesis in C2C12 cultured cells. These findings have important implications for future studies investigating the efficacy of minocycline treatment in neuromuscular or other muscle-atrophy inducing conditions.

Chronic activation of AMP-activated protein kinase increases monocarboxylate transporter 2 and 4 expression in skeletal muscle

2017 ◽  
Vol 95 (8) ◽  
pp. 3552
Author(s):  
E. M. England ◽  
H. Shi ◽  
S. K. Matarneh ◽  
E. M. Oliver ◽  
E. T. Helm ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Monocarboxylate Transporter ◽  
Chronic Activation ◽  
Amp Activated Protein Kinase

scholarly journals Involvement of AMP-activated protein kinase in thrombin-stimulated interleukin 6 synthesis in osteoblasts

2012 ◽  
Vol 49 (1) ◽  
pp. 47-55 ◽  
Author(s):  
H Tokuda ◽  
K Kato ◽  
H Natsume ◽  
A Kondo ◽  
G Kuroyanagi ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Map Kinase ◽  
Interleukin 6 ◽  
P38 Map Kinase ◽  
Thrombin Time ◽  
Rt Pcr ◽  
Α Subunit ◽  
Compound C ◽  
Kinase C ◽  
Amp Activated Protein Kinase

We previously demonstrated that thrombin stimulates synthesis of interleukin 6 (IL6), a potent bone resorptive agent, in part via p44/p42 MAP kinase and p38 MAP kinase but not through stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK) among the MAP kinase superfamily in osteoblast-like MC3T3-E1 cells. In this study, we investigated the involvement of AMP-activated protein kinase (AMPK), a regulator of energy metabolism, in thrombin-stimulated IL6 synthesis in MC3T3-E1 cells. The phosphorylation of p44/p42 MAP kinase, p38 MAP kinase, SAPK/JNK, or AMPK was determined by western blot analysis. The release of IL6 was determined by the measurement of IL6 concentration in the conditioned medium using an ELISA kit. The expression ofIL6mRNA was determined by RT-PCR. Thrombin time dependently induced the phosphorylation of AMPK α-subunit (Thr-172). Compound C, an inhibitor of AMPK, dose-dependently suppressed the thrombin-stimulated IL6 release in the range between 0.3 and 10 μM. Compound C reduced thrombin-induced acetyl-CoA carboxylase phosphorylation. TheIL6mRNA expression induced by thrombin was markedly reduced by compound C. Downregulation of AMPK by siRNA suppressed the thrombin-stimulated IL6 release. The thrombin-induced phosphorylation of p44/p42 MAP kinase and p38 MAP kinase was inhibited by compound C, which failed to affect SAPK/JNK phosphorylation. These results strongly suggest that AMPK regulates thrombin-stimulated IL6 synthesis via p44/p42 MAP kinase and p38 MAP kinase in osteoblasts.

scholarly journals Myosin heavy chain isoform profiles remain altered at 7 months if the lacerated medial gastrocnemius is poorly reinnervated: A study in rabbits

2009 ◽  
Vol 28 (6) ◽  
pp. 732-738 ◽  
Author(s):  
Barry P. Pereira ◽  
Hwan Chour Han ◽  
Zou Yu ◽  
Bee-Leng Tan ◽  
Zheng Ling ◽  
...  
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Medial Gastrocnemius ◽  
Myosin Heavy Chain Isoform

In vitro O2 uptake and histochemical fiber type of resting hamster muscles

1984 ◽  
Vol 57 (1) ◽  
pp. 246-253 ◽  
Author(s):  
S. M. Sullivan ◽  
R. N. Pittman
Keyword(s):  
Surface Area ◽  
Fiber Type ◽  
Oxidative Capacity ◽  
Histochemical Staining ◽  
Striated Muscles ◽  
Type Composition ◽  
Slow Twitch ◽  
Pattern Number ◽  
Fast Twitch

In vitro oxygen consumption (VO2), histochemical fiber type, capillary arrangement, and muscle fiber geometry were measured in three hamster striated muscles. These muscles varied markedly in their histochemical fiber type composition (% by number): retractor (70% FG, fast-twitch, glycolytic; 16% FOG, fast-twitch, oxidative-glycolytic; 14% SO, slow-twitch, oxidative); soleus (57% FOG, 43% SO), and sartorius (98% FG, 2% FOG). Sartorius VO2 [0.80 +/- 0.034 (SE) ml O2 X min-1 X 100 g-1] was significantly different (P less than 0.01) from VO2 of retractor (0.89 +/- 0.038) and soleus (1.00 +/- 0.048).The number of capillaries around a fiber and the surface area/volume were greater for FOG and SO fibers than for FG fibers. Fibers of all types appeared to be roughly elliptical in shape. Capillaries were uniformly distributed around fibers in the soleus, but they were located more toward the ends of the major diameter in the retractor and sartorius. The results suggest a relationship among a fiber's oxidative capacity (based on its histochemical staining pattern), number of surrounding capillaries and surface area/volume. Furthermore, results suggest that VO2 and capillary spacing around a fiber may depend on fiber type.

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