Adaptive transformation of rat soleus motor units during growth

Kugelberg, Eric

doi:10.1016/0022-510x(76)90001-0

Cited by 369 publications

(178 citation statements)

References 36 publications

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“…The intact soleus muscle preparation used in the present study is expected to be populated with 80°7o type I fibres, the rest being type IIA [24,25]. EDL and epitrochlearis muscle both contain > 9007o type II fibres (about 50o70 and 70°70 type IIB fibres, respectively [26,27]).…”

Section: Resultsmentioning

confidence: 99%

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Calcitonin gene‐related peptide‐1 (CGRP‐1) is a potent regulator of glycogen metabolism in rat skeletal muscle

et al. 1989

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We investigated the effects of CGRP on glucose metabolism in intact rat skeletal muscle preparations that are largely composed of either type I (soleus) or II fibres (e.g. extensor digltorum longus (EDL) or epitrochlearis muscles). CGRP-1 inhibited insulin-stimulated glycogen synthesis in both soleus and EDL muscle preparations. Rat CGRP-1 was a potent stimulator of glycogenolysis only in muscles composed of type II fibres, which depend on high rates of glycogenolysis to produce high power outputs. These results may provide the basis for understanding how CGRP regulate glyeogenolysis in type II fibres in vivo.

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Section: Resultsmentioning

confidence: 99%

“…The soleus muscle of the rat has a post-natal period of maturing, and most of the fast-twitch changes to slow twitch fibres occur over the first few months [24,25]. The intact soleus muscle preparation used in the present study is expected to be populated with 80°7o type I fibres, the rest being type IIA [24,25].…”

Section: Resultsmentioning

confidence: 99%

Calcitonin gene‐related peptide‐1 (CGRP‐1) is a potent regulator of glycogen metabolism in rat skeletal muscle

et al. 1989

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“…We selected animals that were fully mature as judged by histochemical development (Karpati & Engel, 1967;Kugelberg, 1976). Body weights of eighteen rats ranged between 315 and 445 g (mean = 395 g, S.D.…”

Section: Methodsmentioning

confidence: 99%

A comparison of the effects of denervation on the mechanical properties of rat and guinea‐pig skeletal muscle.

Al-Amood¹,

Lewis²

1989

The Journal of Physiology

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SUMMARY1. A fast (extensor digitorum longus) and slow (soleus) twitch muscle were denervated in rats and guinea-pigs and isometric and isotonic contractions were followed for periods of up to 6 months after.2. The decay of tetanic tension with time could be described as exponential. The rate of decay of tension was greatest in rat soleus and least in guinea-pig soleus by a factor of more than three. The fast muscles atrophied at intermediate rates.3. The contraction and relaxation times of soleus and extensor digitorum longus of rat, initially prolonged by denervation, became shorter after 3 weeks. There was no such reversal in either guinea-pig muscle, indeed extensor digitorum longus twitch became even more prolonged. Guinea-pig muscles often showed signs of repetitive response to a single stimulus, resulting in distortion of relaxation of the twitch.4. There was a slowing of isotonic shortening velocity in the late stage of denervation of guinea-pig extensor digitorum longus, accompanied by a fall in the rate of development of isometric tetanic tension. There was a just-significant (P < 0-1) increase in the shortening velocity of rat soleus. None of the other muscles showed any change in either rate characteristic.5. In guinea-pig extensor digitorum longus the type I fibres atrophied less than type II fibres; in all other muscles the atrophy was more uniform, possibly faster in type II. Guinea-pig soleus remained pure type I contrasting with an increase in the numbers of type II fibres in rat soleus. There was a possible increase in the number of type I fibres in guinea-pig fast muscle and no change in the rat.

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“…3c), no peptide analysis of the heavy chains was possible. However, from earlier immunochemical [5] and histochemical [43] studies it may be concluded that IIC fibers contain a mixture of slow and fast heavy chains. The correlation between fiber type and myosin heavy chain suggests that the histochemical ATPase is determined solely by the heavy chain and not by the light chains.…”

Section: Myosin Heavy Chain In Single Human Muscle Fibersmentioning

confidence: 99%

“…IIC fibers are considered to be a transitional form through which fibers pass when they transform from type I to type I1 and vice versa. Such transformations can occur in response to chronic electrical stimulation ( & + I , for review see [45]) and during postnatal development in the rat soleus ( I I k I [43]). In man, transformations of the kind IIA-+I as well as I I A Z I I B have been reported to occur as a result of physical training [46].…”

Section: Myosin Heavy Chain In Single Human Muscle Fibersmentioning

confidence: 99%

Analysis of Myosin Light and Heavy Chain Types in Single Human Skeletal Muscle Fibers

et al. 1981

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In this study, myosin types in human skeletal muscle fibers were investigated with electrophoretic techniques. Single fibers were dissected out of lyophilized surgical biopsies and typed by staining for myofibrillar ATPase after preincubation in acid or alkaline buffers. After I4C-labeling of the fiber proteins in v i m by reductive methylation, the myosin light chain pattern was analysed on two-dimensional gels and the myosin heavy chains were investigated by one-dimensional peptide mapping. Surprisingly, human type I fibers, which contained only the slow heavy chain, were found to contain variable amounts of fast myosin light chains in addition to the two slow light chains LCls and LC2s. The majority of the type I fibers in normal human muscle showed the pattern LCls, LC2s and LClf. Further evidence for the existence in human muscle of a hybrid myosin composed of a slow heavy chain with fast and slow light chains comes from the analysis of purified human myosin in the native state by pyrophosphate gel electrophoresis. With this method, a single band corresponding to slow myosin was obtained ; this slow myosin had the light chain composition LCls, LC2s and LClf.Type IIA and IIB fibers, on the other hand, revealed identical light chain patterns consisting of only the fast light chains LClf, LC2f and LC3f but were found to have different myosin heavy chains.On the basis of the results presented, we suggest that thc histochemical ATPase normally used for fibre typing is determined by the myosin heavy chain type (and not by the light chains). Thus, in normal human muscle a number of 'hybrid' myosins were found to occur, namely two extreme forms of fast myosins which have the same light chains but different heavy chains (IIA and IIB) and a continuum of slow forms consisting of the same heavy chain and slow light chains with a variable Fast light chain composition. This is consistent with the different physiological roles these fibers are thought to have in muscle contraction.

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Adaptive transformation of rat soleus motor units during growth

Cited by 369 publications

References 36 publications

Calcitonin gene‐related peptide‐1 (CGRP‐1) is a potent regulator of glycogen metabolism in rat skeletal muscle

Calcitonin gene‐related peptide‐1 (CGRP‐1) is a potent regulator of glycogen metabolism in rat skeletal muscle

A comparison of the effects of denervation on the mechanical properties of rat and guinea‐pig skeletal muscle.

Analysis of Myosin Light and Heavy Chain Types in Single Human Skeletal Muscle Fibers

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