Enzymatic plasticity of medial gastrocnemius fibers in the adult chronic spinal cat

1990 ◽  
Vol 259 (3) ◽  
pp. C507-C514 ◽  
Author(s):  
B. Jiang ◽  
R. R. Roy ◽  
V. R. Edgerton
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Fiber Type ◽  
Motor Units ◽  
Glycolytic Enzyme ◽  
Medial Gastrocnemius ◽  
Fiber Types ◽  
Cross Sectional ◽  
Fast Myosin ◽  
Weight Support

The metabolic plasticity of single fibers in adult cat medial gastrocnemius (MG) 6 mo after complete spinal cord transection (Sp) at T12-T13 was studied. Some Sp cats were trained to weight support (Sp-WS) 30 min/day beginning 1 mo posttransection. Cross-sectional area, succinate dehydrogenase (SDH), alpha-glycerophosphate dehydrogenase (GPD), and myofibrillar adenosinetriphosphatase (ATPase) activities were determined in fibers identified in frozen serial sections. Fibers were categorized as light or dark based on myosin ATPase staining, alkaline preincubation. The percentage of dark ATPase fibers was higher in Sp and Sp-WS (approximately 85%) than in control (approximately 60%). All dark ATPase fibers reacted positively to a fast myosin heavy chain monoclonal antibody. In both spinal groups, a higher percentage of dark ATPase fibers reacted to both fast and slow myosin heavy chain antibodies than in controls. Neither Sp nor Sp-WS cats showed fiber atrophy. Compared with control, SDH activity was decreased in both fiber types of Sp cats. Daily weight-support training ameliorated this adaptation. There were no differences among the three groups in mean GPD and ATPase activities for either fiber type. There was a slight tendency, however, for spinal cats to have higher GPD and ATPase activities (independent of type) than control, probably reflecting the larger proportion of dark ATPase fibers in these cats. These observations indicate that 6 mo after spinalization in adult cats, some of the fibers of a fast muscle became "faster" and developed oxidative and glycolytic enzyme profiles that normally are exhibited in fast fatigable motor units.(ABSTRACT TRUNCATED AT 250 WORDS)

Enhancement of hybrid-fiber types in rat soleus muscle after clenbuterol administration during hindlimb unloading

2004 ◽  
Vol 82 (5) ◽  
pp. 311-318 ◽  
Author(s):  
F Picquet ◽  
L De-Doncker ◽  
M Falempin
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Fiber Type ◽  
Myosin Heavy Chain Isoforms ◽  
Hindlimb Unloading ◽  
Fiber Types ◽  
Myosin Isoforms ◽  
Fast Myosin ◽  
Contractile Parameters ◽  
Fast Myosin Heavy Chain

Our objective was to determine the effects of a clenbuterol (CB) treatment orally administered (2 mg per kg) to rats submitted to 14 days of hindlimb unloading (HU). The morphological and the contractile properties as well as the myosin heavy chain isoforms contained in each fiber type were determined in whole soleus muscles. As classically described after HU, a decrease in muscle wet weight and in body mass associated with a loss of muscular force, an evolution of the contractile parameters towards those of a fast muscle type, and the emergence of fast myosin heavy chain isoforms were observed. The CB treatment in the HU rats helped reduce the decrease in 1) muscle and body weights, 2) force and 3) the proportion of slow fibers, without preventing the emergence of fast myosin isoforms. Clenbuterol induced a complex remodelling of the muscle typing promoting the combination of both slow and fast myosin isoforms within one fiber. To conclude, our data demonstrate that CB administration partially counteracts the effects produced by HU, and they allow us to anticipate advances in the treatment of muscular atrophy.Key words: β2 agonist, clenbuterol, soleus, contractile parameters, myosin, immunohistochemistry, simulated microgravity, countermeasure.

scholarly journals The histochemical profiles of fast fiber types IIB, IID, and IIA in skeletal muscles of mouse, rat, and rabbit.

1993 ◽  
Vol 41 (5) ◽  
pp. 733-743 ◽  
Author(s):  
N Hämäläinen ◽  
D Pette
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Skeletal Muscles ◽  
Fiber Type ◽  
Vastus Lateralis ◽  
Fiber Types ◽  
Cross Sectional ◽  
Fast Fiber ◽  
Myosin Heavy Chain Composition ◽  
Biochemical Analyses

This study characterized histochemically three fast fiber types (IIB, IID, IIA) in skeletal muscles of mouse, rat, and rabbit, with special reference to fiber types IIB and IID. The results are complemented by biochemical analyses of myosin heavy chain composition in these muscles. Fiber type delineation is based on various methods for mATPase staining with pre-incubations and assays under different conditions. In rat and mouse, IIB and IID fibers can be best distinguished according to their different mATPase stabilities towards formaldehyde and alkaline pH. In rabbit, the method of Matoba and Gollnick using acid pre-incubation provided best and most reproducible results. In addition to their different mATPase stabilities, the three fast fiber types differ with regard to their oxidative capacities and cross-sectional fiber areas in the three species. In general, Type IIB fibers are the largest and least oxidative, Type IIA fibers the smallest and most oxidative, and Type IID fibers intermediate. In rabbit, Type IID fibers are the predominant fast fiber population in extensor digitorum longus, psoas, and tibialis anterior muscles. As judged from histochemistry, these muscles of rabbit do not contain pure Type IIB fibers. This is in accordance with biochemical results that show the HCIId to form the majority of the myosin heavy chain complement expressed in these muscles. On the other hand, IIB fibers are numerous in rabbit adductor magnus, gastrocnemius, and vastus lateralis muscles. Similarly, appreciable amounts of myosin heavy chain HCIIb are found in the three latter muscles of rabbit.

Myosin Heavy Chain Composition in Human Masticatory Muscles by Immunohistochemistry and Gel Electrophoresis

2003 ◽  
Vol 51 (1) ◽  
pp. 113-119 ◽  
Author(s):  
J.A.M. Korfage ◽  
T.M.G.J. Van Eijden
Keyword(s):  
Myosin Heavy Chain ◽  
Correlation Coefficient ◽  
Heavy Chain ◽  
Fiber Type ◽  
Masticatory Muscles ◽  
Digastric Muscle ◽  
Type I ◽  
Fiber Types ◽  
Hybrid Fibers ◽  
Cross Sectional

In this study we compared the immunohistochemically quantified fiber type area with the myosin heavy chain (MyHC) contents of a bundle of fibers from a human masticatory muscle. The total cross-sectional areas were determined immunohistochemically for the three major fiber types (I, IIA, and IIX) in bundles of fibers ( n = 42) taken from the anterior and posterior belly of the human digastric muscle ( n = 7). The relative MyHC contents of the same fiber bundles were determined electrophoretically (MyHC-I, -IIA, and -IIX; anterior, 32%, 35%, and 33%; posterior, 39%, 42%, and 19%) and compared with the immunohistochemical data (MyHC-I, -IIA, and -IIX; anterior, 32%, 31%, and 37%; posterior, 39%, 45%, and 15%). No significant differences were seen in the mean fiber type distribution between the two techniques; the correlation coefficient ranged from 0.71 to 0.96. The correlation coefficient was higher for MyHC type I and MyHC type IIX than for MyHC type IIA. The MyHC contents of single fibers taken from the posterior belly indicated that many fibers in this belly co-express MyHC-IIA and MyHC-IIX. Despite the presence of these hybrid fibers, the correspondence between both methods was relatively large.

Effects of periodic weight support on medial gastrocnemius fibers of suspended rat

1989 ◽  
Vol 67 (3) ◽  
pp. 945-953 ◽  
Author(s):  
S. C. Graham ◽  
R. R. Roy ◽  
E. O. Hauschka ◽  
V. R. Edgerton
Keyword(s):  
Muscle Fiber ◽  
Enzyme Activities ◽  
Motor Units ◽  
Cross Sectional Area ◽  
Medial Gastrocnemius ◽  
Fiber Types ◽  
Sectional Area ◽  
Cross Sectional ◽  
Weight Support ◽  
The Mean

Based on the current view that muscle fiber types reflect, at least to some degree, the probability of excitation of motor units in most normal movements, it was hypothesized that brief moderate periods of weight support would have little effect on a muscle that consists predominantly of high-threshold motor units. To test this hypothesis, the effects of 7 days of hindlimb suspension (HS) and HS plus intermittent weight support activity on the size and metabolic properties of individual fibers in the medial gastrocnemius (MG) were studied. HS resulted in a 40% decrease in the mean cross-sectional area of fibers that stain either dark or light for myosin adenosinetriphosphatase (ATPase) at an alkaline preincubation and are located in the deep region (i.e., close to the bone) of the MG. Dark ATPase fibers located in the superficial region were 17% smaller than controls (P greater than 0.05). Although the mean succinate and alpha-glycerophosphate dehydrogenase activities (optical density/min) per muscle fiber were not significantly (P greater than 0.05) affected by HS, it appeared that selected fibers of the deep MG region of HS rats had elevated enzyme activities. HS plus walking on a treadmill for 10 min every 6 h at 5 m/min and at a 19 degrees incline (total of 40 min/day) resulted in mean fiber cross-sectional area and enzyme activities nearer to control than the HS values. All adaptations were much less obvious in the fibers in a superficial (i.e., away from the bone) MG region.(ABSTRACT TRUNCATED AT 250 WORDS)

Size and metabolic properties of fibers in rat fast-twitch muscles after hindlimb suspension

1987 ◽  
Vol 62 (6) ◽  
pp. 2348-2357 ◽  
Author(s):  
R. R. Roy ◽  
M. A. Bello ◽  
P. Bouissou ◽  
V. R. Edgerton
Keyword(s):  
Fiber Type ◽  
Female Rats ◽  
Medial Gastrocnemius ◽  
Hindlimb Suspension ◽  
Staining Reaction ◽  
Fiber Types ◽  
Image Analysis System ◽  
Cross Sectional ◽  
Glycerophosphate Dehydrogenase ◽  
Metabolic Marker

Hindlimb suspension (HS) results in whole muscle atrophic and metabolic changes that vary in magnitude in different hindlimb muscles. The present study was designed to investigate these effects in single fibers. Fiber type and size and the activities of two metabolic marker enzymes were determined in a deep (close to the bone) and a superficial (away from the bone) region of the medial gastrocnemius (MG) and the tibialis anterior (TA) of control (CON) and 28-day HS adult female rats. Fibers were classified as dark or light adenosinetriphosphatase (ATPase) based on their qualitative staining reaction for myosin ATPase following alkaline preincubation. Fiber area and succinate dehydrogenase (SDH) and alpha-glycerophosphate dehydrogenase (GPD) activities were determined in tissue sections by use of an image analysis system. After 28 days of HS, the mean body weights of the CON and HS were similar. MG atrophied 28%, whereas TA weight was maintained in the HS. Both dark and light ATPase fibers in the deep region of the MG had smaller cross-sectional areas following HS, with the atrophic response being approximately twice as great in the light ATPase fibers. No significant changes in fiber type composition in either muscle or in fiber sizes in the superficial region of the MG or in either region of the TA were observed. Mean SDH activities of both fiber types were significantly lower in the MG and TA following HS. In contrast, mean GPD activities were either increased or maintained in light and dark ATPase fibers of both muscles in HS. Changes in SDH and GPD activity could not be directly linked to changes in fiber cross-sectional area. In summary, these data suggest an independence of the mechanisms determining muscle fiber size and metabolic adaptations associated with HS.

Adaptations in physiological properties of rat motor units following 5 weeks of whole-body vibration

2013 ◽  
Vol 38 (9) ◽  
pp. 913-921 ◽  
Author(s):  
Dawid Łochyński ◽  
Marcin Bączyk ◽  
Dominik Kaczmarek ◽  
Maria Jolanta Rędowicz ◽  
Jan Celichowski ◽  
...  
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Whole Body Vibration ◽  
Motor Units ◽  
Medial Gastrocnemius ◽  
Whole Body ◽  
Force Frequency ◽  
Body Vibration ◽  
Myosin Heavy Chain Isoform ◽  
Twitch Contraction

The purpose of the study was to determine the effects of 5-week whole-body vibration (WBV) on contractile parameters and force–frequency relationship of functionally isolated motor units of the rat medial gastrocnemius muscle: fast fatigable (FF), fast fatigue-resistant (FR), and slow (S). Moreover, myosin heavy chain isoform content was quantified. Following WBV, the maximum tetanic force of FF units was increased by ∼25%. The twitch half-relaxation time in all types of motor units and the twitch contraction time in FR units were shortened. The twitch-to-tetanus force ratio was decreased and the force–frequency curves were shifted rightwards in S and FR units. Myosin heavy chain distribution was not changed. These findings suggest modifications of the excitation–contraction coupling towards shortening of a twitch contraction. The observed increase in force of FF units may contribute to gains in muscle dynamic strength reported following WBV treatment.

Hypertrophy of rat plantaris muscle fibers after voluntary running with increasing loads

1998 ◽  
Vol 84 (6) ◽  
pp. 2183-2189 ◽  
Author(s):  
Akihiko Ishihara ◽  
Roland R. Roy ◽  
Yoshinobu Ohira ◽  
Yasuhiko Ibata ◽  
V. Reggie Edgerton
Keyword(s):  
Wheel Running ◽  
Fiber Type ◽  
Motor Units ◽  
Control Group ◽  
Fiber Types ◽  
Total Work ◽  
Sprague Dawley ◽  
Cross Sectional ◽  
Hypertrophic Response ◽  
Voluntary Running

There have been no systematic comparisons of skeletal muscle adaptations in response to voluntary wheel running under controlled loading conditions. To accomplish this, a voluntary running wheel for rats and mice was developed in which a known load can be controlled and monitored electronically. Five-week-old male Sprague-Dawley rats (10 rats/group) were assigned randomly to either a 1) sedentary control group (Control); 2) voluntary exercised with no load (Run-No-Load) group; or 3) voluntary exercised with additional load (Run-Load) group for 8 wk. The load for the Run-Load group was progressively increased to reach ∼60% of body weight during the last week of training. The proportions of fast glycolytic (FG), fast oxidative glycolytic (FOG), or slow oxidative (SO) fibers in the plantaris were similar in all groups. The absolute and relative plantaris weights were greater in the Run-Load group compared with the Control and Run-No-Load groups. The mean fiber cross-sectional areas of FG, FOG, and SO fibers were 20, 25, and 15% greater in the Run-Load than in Control rats. In addition, these fiber types were 16, 21, and 12% larger in Run-Load than in Run-No-Load rats. The muscle weights and mean cross-sectional areas of each fiber type were highly correlated with the average running distances and total work performed in the Run-Load, but not the Run-No-Load, group. The slope of the relationship between fiber size and running distance and total work performed was significant for each fiber type but was higher for FG and FOG fibers compared with SO fibers. These data show that the load on a rat running voluntarily can determine the magnitude of a hypertrophic response and the population of motor units that are recruited to perform at a given loading condition.

Maximum specific force depends on myosin heavy chain content in rat diaphragm muscle fibers

2000 ◽  
Vol 89 (2) ◽  
pp. 695-703 ◽  
Author(s):  
Paige C. Geiger ◽  
Mark J. Cody ◽  
Rebecca L. Macken ◽  
Gary C. Sieck
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Fiber Type ◽  
Diaphragm Muscle ◽  
Specific Force ◽  
Rat Diaphragm ◽  
Cross Sectional ◽  
High Calcium ◽  
Cross Bridges ◽  
Triton X

In the present study, myosin heavy chain (MHC) content per half sarcomere, an estimate of the number of cross bridges available for force generation, was determined in rat diaphragm muscle (Diam) fibers expressing different MHC isoforms. We hypothesize that fiber-type differences in maximum specific force [force per cross-sectional area (CSA)] reflect the number of cross bridges present per CSA. Studies were performed on single, Triton X-100-permeabilized rat Diam fibers. Maximum specific force was determined by activation of single Diamfibers in the presence of a high-calcium solution (pCa, −log Ca2+ concentration of 4.0). SDS-PAGE and Western blot analyses were used to determine MHC isoform composition and MHC content per half sarcomere. Differences in maximum specific force across fast MHC isoforms were eliminated when controlled for half-sarcomere MHC content. However, the force produced by slow fibers remained below that of fast fibers when normalized for the number of cross bridges available. On the basis of these results, the lower force produced by slow fibers may be due to less force per cross bridge compared with fast fibers.

scholarly journals Contractile properties of motor units and expression of myosin heavy chain isoforms in rat fast-type muscle after volitional weight-lifting training

2016 ◽  
Vol 121 (4) ◽  
pp. 858-869 ◽  
Author(s):  
Dawid Łochyński ◽  
Dominik Kaczmarek ◽  
Włodzimierz Mrówczyński ◽  
Wojciech Warchoł ◽  
Joanna Majerczak ◽  
...  
Keyword(s):  
Resistance Training ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Motor Units ◽  
Weight Lifting ◽  
Contractile Properties ◽  
Medial Gastrocnemius ◽  
Maximum Force ◽  
Force Frequency ◽  
Contractile Characteristics

Dynamic resistance training increases the force and speed of muscle contraction, but little is known about modifications to the contractile properties of the main physiological types of motor units (MUs) that contribute to these muscle adaptations. Although the contractile profile of MU muscle fibers is tightly coupled to myosin heavy chain (MyHC) protein expression, it is not well understood if MyHC transition is a prerequisite for modifications to the contractile characteristics of MUs. In this study, we examined MU contractile properties, the mRNA expression of MyHC, parvalbumin, and sarcoendoplasmic reticulum Ca2+pump isoforms, as well as the MyHC protein content after 5 wk of volitional progressive weight-lifting training in the medial gastrocnemius muscle in rats. The training had no effect on MyHC profiling or Ca2+-handling protein gene expression. Maximum force increased in slow (by 49%) and fast (by 21%) MUs. Within fast MUs, the maximum force increased in most fatigue-resistant and intermediate but not most fatigable MUs. Twitch contraction time was shortened in slow and fast fatigue-resistant MUs. Twitch half-relaxation was shortened in fast most fatigue-resistant and intermediate MUs. The force-frequency curve shifted rightward in fast fatigue-resistant MUs. Fast fatigable MUs fatigued less within the initial 15 s while fast fatigue-resistant units increased the ability to potentiate the force within the first minute of the standard fatigue test. In conclusion, at the early stage of resistance training, modifications to the contractile characteristics of MUs appear in the absence of MyHC transition and the upregulation of Ca2+-handling genes.

Enzyme profiles of single muscle fibers never exposed to normal neuromuscular activity

1990 ◽  
Vol 69 (3) ◽  
pp. 1150-1158 ◽  
Author(s):  
S. J. Hoffmann ◽  
R. R. Roy ◽  
C. E. Blanco ◽  
V. R. Edgerton
Keyword(s):  
Fiber Type ◽  
Muscle Fibers ◽  
Myosin Atpase ◽  
Medial Gastrocnemius ◽  
Normal Adult ◽  
Fiber Types ◽  
Marker Enzyme ◽  
Spinal Transection ◽  
Cross Sectional ◽  
The Cross

Do muscle fiber properties commonly associated with fiber types in adult animals and the population distribution of these properties require normal activation patterns to develop? To address this issue, the activity of an oxidative [succinic dehydrogenase (SDH)] and a glycolytic [alpha-glycerophosphate dehydrogenase (GPD)] marker enzyme, the characteristics of myosin adenosinetriphosphatase (myosin ATPase, alkaline preincubation), and the cross-sectional area of single fibers were studied. The soleus and medial gastrocnemius of normal adult cats were compared with cats that 6 mo earlier had been spinally transected at T12-T13 at 2 wk of age. In control cats, SDH activity was higher in dark than light ATPase fibers in the soleus and higher in light than dark ATPase fibers in the medial gastrocnemius. After transection, SDH activity was similar to control in both muscles. GPD activity appeared to be elevated in some fibers in each fiber type in both muscles after transection. The cross-sectional areas most affected by spinal transection were light ATPase fibers of the soleus and dark ATPase fibers of the medial gastrocnemius, the predominant fiber type in each muscle. These data demonstrate that although the muscle fibers of cats spinalized at 2 wk of age presumably were never exposed to normal levels of activation, the activity of an oxidative marker enzyme was maintained or elevated 6 mo after spinal transection. Furthermore, although the absolute enzyme activities in some fibers were elevated by transection, three functional protein systems commonly associated with fiber types, i.e., hydrolysis of ATP by myosin ATPase and glycolytic (GPD) and oxidative (SHD) metabolism, developed in a coordinated manner typical of normal adult muscles.

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