Interaction between myoglobin and mitochondria in rat skeletal muscle

The mechanisms underlying subcellular oxygen transport mediated by myoglobin (Mb) remain unclear. Recent evidence suggests that, in the myocardium, transverse diffusion of Mb is too slow to effectively supply oxygen to meet the immediate mitochondrial oxygen demands at the onset of muscle contractions. The cell may accommodate the demand by maintaining the distribution of Mb to ensure a sufficient O2 supply in the immediate vicinity of the mitochondria. The present study has verified the co-localization of Mb with mitochondria by using biochemical histological and electron microscopy analyses. Immunohistochemical and electron microscopy analysis indicates a co-localization of Mb with mitochondria. Western blotting confirms the presence of Mb colocalizes with the mitochondrial fraction and appears more prominently in slow-twitch oxidative than in fast-twitch glycolytic muscle. In particular, Mb interacts with cytochrome c oxidase-subunit IV. These results suggest that a direct Mb-mediated O2 delivery to the mitochondria, which may play a potentially significant role for respiration.

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Diazepam reveals different rate-limiting processes in rat skeletal muscle contraction

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y87-048 ◽

1987 ◽

Vol 65 (2) ◽

pp. 272-273 ◽

Cited By ~ 7

Author(s):

Michael Chua ◽

Angela F. Dulhunty

Keyword(s):

Skeletal Muscle ◽

Sarcoplasmic Reticulum ◽

Calcium Binding ◽

Extensor Digitorum Longus ◽

Calcium Uptake ◽

Rat Skeletal Muscle ◽

Skeletal Muscle Contraction ◽

Slow Twitch ◽

Fast Twitch ◽

Rate Limiting

The action of the tranquilizer diazepam on rat skeletal muscle showed that relaxation of isometric twitches is controlled by different processes in extensor digitorum longus (fast-twitch) and soleus (slow-twitch) muscles. Diazepam caused an increase in the amplitude of twitches in fibres from both muscles but increased the twitch duration only in soleus. The amplitude of fused tetani were reduced in both muscles and the rate of relaxation after the tetanus slowed by as much as 34% when the amplitude of the tetanus was reduced by only 11%. The slower tetanic relaxation indicated that calcium uptake by the sarcoplasmic reticulum was slower than normal in slow- and fast-twitch fibres. We conclude therefore that calcium uptake by the sarcoplasmic reticulum is rate limiting for twitch relaxation in slow-twitch but not fast-twitch fibres and suggest that calcium binding to parvalbumin controls relaxation in the fast fibres.

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Localization of sarcoplasmic reticulum proteins in rat skeletal muscle by immunofluorescence.

The Journal of Cell Biology ◽

10.1083/jcb.80.2.372 ◽

1979 ◽

Vol 80 (2) ◽

pp. 372-384 ◽

Cited By ~ 89

Author(s):

A O Jorgensen ◽

V Kalnins ◽

D H MacLennan

Keyword(s):

Skeletal Muscle ◽

Sarcoplasmic Reticulum ◽

Immunofluorescent Staining ◽

Mammalian Skeletal Muscle ◽

Rat Skeletal Muscle ◽

Ultrastructural Studies ◽

Band Region ◽

Slow Twitch ◽

Fast Twitch ◽

Cryostat Sections

Ca++-Mg++-dependent ATPase and calsequestrin, the major intrinsic and extrinsic proteins, respectively, of the sarcoplasmic reticulum, were localized in cryostat sections of adult rat skeletal muscle by immunofluorescent staining and phase-contrast microscopy. Relatively high concentrations of both the ATPase and calsequestrin were found in fast-twitch myofibers while a very low concentration of the ATPase and a moderate concentration of calsequestrin were found in slow-twitch myofibers. These findings are consistent with previous biochemical studies of the isolated sarcoplasmic reticulum of slow-twitch and fast-twitch mammalian muscles. The distribution of the ATPase in muscle fibers is distinctly different from that of calsequestrin. While calsequestrin is present only near the interface between the I- and A-band regions of the sarcomere, the ATPase is found throughout the I-band region as well as in the center of the A-band region. In comparing these results with in situ ultrastructural studies of the distribution of sarcoplasmic reticulum in fast-twitch muscle, it appears that the ATPase is rather uniformly distributed throughout the sarcoplasmic reticulum while calsequestrin is almost exclusively confined to those regions of the membrane system which correspond to terminal cisternae. Fluorescent staining with these antisera was not observed in vascular smooth muscle cells present in the cryostat sections of the mammalian skeletal muscle used in this study.

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Collagen of slow twitch and fast twitch muscle fibres in different types of rat skeletal muscle

European Journal of Applied Physiology and Occupational Physiology ◽

10.1007/bf00433399 ◽

1984 ◽

Vol 52 (2) ◽

pp. 235-242 ◽

Cited By ~ 64

Author(s):

V. Kovanen ◽

H. Suominen ◽

E. Heikkinen

Keyword(s):

Skeletal Muscle ◽

Muscle Fibres ◽

Rat Skeletal Muscle ◽

Different Types ◽

Fast Twitch Muscle ◽

Slow Twitch ◽

Fast Twitch

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Diet-induced obesity and acute hyperlipidemia reduce IκBα levels in rat skeletal muscle in a fiber-type dependent manner

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00097.2005 ◽

2006 ◽

Vol 290 (1) ◽

pp. R233-R240 ◽

Cited By ~ 33

Author(s):

Bankim A. Bhatt ◽

John J. Dube ◽

Nikolas Dedousis ◽

Jodie A. Reider ◽

Robert M. O’Doherty

Keyword(s):

Skeletal Muscle ◽

P38 Mapk ◽

Fiber Type ◽

Dependent Manner ◽

Rat Skeletal Muscle ◽

Diet Induced Obesity ◽

Slow Twitch ◽

Fast Twitch ◽

Fat Feeding ◽

Increased Activity

Increased activity of proinflammatory/stress pathways has been implicated in the pathogenesis of insulin resistance in obesity. However, the effects of obesity on the activity of these pathways in skeletal muscle, the major insulin-sensitive tissue by mass, are poorly understood. Furthermore, the mechanisms that activate proinflammatory/stress pathways in obesity are unknown. The present study addressed the effects of diet-induced obesity (DIO; 6 wk of high-fat feeding) and acute (6-h) hyperlipidemia (HL) in rats on activity of IKK/IκB/NF-κB c-Jun NH2-terminal kinase, and p38 MAPK in three skeletal muscles differing in fiber type [superficial vastus (Vas; fast twitch-glycolytic), soleus (Sol; slow twitch-oxidative), and gastrocnemius (Gas; mixed)]. DIO decreased the levels of the IκBα in Vas (24 ± 3%, P = 0.001, n = 8) but not in Sol or Gas compared with standard chow-fed controls. Similar to DIO, HL decreased IκBα levels in Vas (26 ± 5%, P = 0.006, n = 6) and in Gas (15 ± 4%, P = 0.01, n = 7) but not in Sol compared with saline-infused controls. Importantly, the fiber-type-dependent effects on IκBα levels could not be explained by differential accumulation of triglyceride in Sol and Vas. HL, but not DIO, decreased phospho-p38 MAPK levels in Vas (41 ± 7% P = 0.004, n = 6) but not in Sol or Gas. Finally, skeletal muscle c-Jun NH2-terminal kinase activity was unchanged by DIO or HL. We conclude that diet-induced obesity and acute HL reduce IκBα levels in rat skeletal muscle in a fiber-type-dependent manner.

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Effect of colchicine on alkaline triglyceride lipase activity and triglyceride content in rat skeletal muscle

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y88-254 ◽

1988 ◽

Vol 66 (12) ◽

pp. 1555-1559 ◽

Cited By ~ 3

Author(s):

J. Gorski ◽

W. C. Miller ◽

W. K. Palmer ◽

L. B. Oscai

Keyword(s):

Skeletal Muscle ◽

Enzyme Activity ◽

Lipase Activity ◽

Colchicine Treatment ◽

Rat Skeletal Muscle ◽

Potent Inducer ◽

Triglyceride Content ◽

Slow Twitch ◽

Muscle Groups ◽

Fast Twitch

One purpose of this study was to determine if colchicine increased intracellular alkaline triglyceride (TG) lipase activity above control levels in rat skeletal muscle. The second aim was to determine the effects of colchicine treatment on the concentration of TG in skeletal muscle. The results show that colchicine was a potent inducer of alkaline TG lipase activity, increasing enzyme activity approximately twofold in slow-twitch red, fast-twitch red, and fast-twitch white muscle types. It was found that in slow-twitch red soleus and fast-twitch red vastus, the two muscle groups with the highest levels of enzyme activity, 76% or more of enzyme activity resides in the intracellular compartment. These results provide evidence that colchicine blocks the export of alkaline TG lipase from skeletal muscle cells similar to that seen in the heart. The finding that TG were reduced at a time when enzyme activity was elevated suggests that intracellular alkaline TG lipase may be playing a role in the hydrolysis of the intramuscular TG droplet.

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Effect of catecholamines on glucose uptake and glycogenolysis in rat skeletal muscle

AJP Cell Physiology ◽

10.1152/ajpcell.1985.248.5.c406 ◽

1985 ◽

Vol 248 (5) ◽

pp. C406-C409 ◽

Cited By ~ 68

Author(s):

D. A. Young ◽

H. Wallberg-Henriksson ◽

J. Cranshaw ◽

M. Chen ◽

J. O. Holloszy

Keyword(s):

Skeletal Muscle ◽

Sugar Transport ◽

Beta Agonist ◽

Sugar Uptake ◽

Rat Skeletal Muscle ◽

Adrenergic Control ◽

Slow Twitch ◽

Fast Twitch ◽

Alpha Agonist

The effect of catecholamines on glycogenolysis and sugar transport was evaluated in rat epitrochlearis (fast-twitch) and soleus (slow-twitch) muscles in vitro. When muscles were incubated with 0.1 microM epinephrine (both an alpha- and beta-agonist), the proportion of phosphorylase in the a form increased from 6.2 +/- 0.7 to 37.4 +/- 5.7% in epitrochlearis muscle and from 9.1 +/- 0.7 to 21.6 +/- 1.3% in soleus muscle. Both the activation of phosphorylase and the resulting glycogenolysis could be prevented by preincubation with the beta-blocker, propranolol. The effect of catecholamines on the rate of sugar transport was also examined in epitrochlearis muscle. The beta-agonist, isoproterenol, significantly depressed the rate of 3-O-methylglucose uptake, while the alpha-agonist, phenylephrine, had no effect. Inclusion of 0.1% albumin in the incubation medium increased the resting rate of sugar transport twofold. When isoproterenol + albumin were present, rather than exerting a depressive effect the catecholamine further increased the rate of sugar uptake. This increase was prevented by preincubation with propranolol. It was concluded that glycogenolysis and sugar transport in rat skeletal muscle are solely under beta-adrenergic control.

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