scholarly journals Revisiting the peculiar regional distribution of muscle fiber types in rat Sternomastoid Muscle

2018 ◽  
Vol 28 (1) ◽  
Author(s):  
Barbara Ravara ◽  
Valerio Gobbo ◽  
Damiana Incendi ◽  
Andrea Porzionato ◽  
Veronica Macchi ◽  
...  
Keyword(s):  
Cross Sections ◽  
Muscle Fibers ◽  
Regional Distribution ◽  
Absolute Number ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Types Of Muscle Fibers ◽  
Deep Region ◽  
Whole Muscle

The sternomastoid (SM) muscle in rodents is known to have a peculiar distribution of fiber types with a steep gradient from surface to deep region. We here further characterize this peculiar regional distribution by quantitative histochemical morphometrys. In Hematoxylin-Eosin (H-E) stained transverse cryosections harvested in the medial portion of the muscle we counted around 10.000 myofibers with a mean diameter of 51.3±12.6 (μm). Cryisections of the SM stained by SDH reaction clearly show two distinct regions, toward the deep surface of the muscle a 40% area that contains packed SDH-positive myofibers, while the remaining area of the SM toward the external surface presents a more checker-board appearance. On the other hand, in the deep region of SM type 1 (slow contracting) muscle fibers, caracterized by positive acidic ATPase pH 4.35 reaction, are only the 24.5% of the fibers in the deep area of SM muscles, being restricted to the deepest region. The 75.5% of the myofibers in the deep region are of the fast contracting types (either 48.4% 2A, SDH –positive fibers or 27.1% 2B, SDH-negative fibers, respectively). As expected the 2B muscle fibers, acidic ATPase pH 4.3-negative and SDH-negative, present the largest size, while Type 1 fibers, acidic ATPase pH 4.3-positive and SDH-positive, present the smallest size in rat SM muscle. Based on present and previous observations, comparison of change in absolute number and/or percentage of the fiber types in any experimental model of muscle atrophy/hypertrophy/plasticity/pathology /recovery in the rat SM, and possibly of all mammals, will ask for morphometry of the whole muscle cross-sections, muscle sampling by bioptic approches will provide only comparable data on the size of the different types of muscle fibers.

The KATP channel Kir6.2 subunit content is higher in glycolytic than oxidative skeletal muscle fibers

2011 ◽  
Vol 301 (4) ◽  
pp. R916-R925 ◽  
Author(s):  
Krystyna Banas ◽  
Charlene Clow ◽  
Bernard J. Jasmin ◽  
Jean-Marc Renaud
Keyword(s):  
Skeletal Muscle ◽  
Cross Sections ◽  
Fiber Type ◽  
Energy Levels ◽  
Muscle Fibers ◽  
Metabolic Stress ◽  
Oxidative Capacity ◽  
Fiber Types ◽  
Fiber Damage ◽  
The Individual

It has long been suggested that in skeletal muscle, the ATP-sensitive K+ channel (KATP) channel is important in protecting energy levels and that abolishing its activity causes fiber damage and severely impairs function. The responses to a lack of KATP channel activity vary between muscles and fibers, with the severity of the impairment being the highest in the most glycolytic muscle fibers. Furthermore, glycolytic muscle fibers are also expected to face metabolic stress more often than oxidative ones. The objective of this study was to determine whether the t-tubular KATP channel content differs between muscles and fiber types. KATP channel content was estimated using a semiquantitative immunofluorescence approach by staining cross sections from soleus, extensor digitorum longus (EDL), and flexor digitorum brevis (FDB) muscles with anti-Kir6.2 antibody. Fiber types were determined using serial cross sections stained with specific antimyosin I, IIA, IIB, and IIX antibodies. Changes in Kir6.2 content were compared with changes in CaV1.1 content, as this Ca2+ channel is responsible for triggering Ca2+ release from sarcoplasmic reticulum. The Kir6.2 content was the lowest in the oxidative soleus and the highest in the glycolytic EDL and FDB. At the individual fiber level, the Kir6.2 content within a muscle was in the order of type IIB > IIX > IIA ≥ I. Interestingly, the Kir6.2 content for a given fiber type was significantly different between soleus, EDL, and FDB, and highest in FDB. Correlations of relative fluorescence intensities from the Kir6.2 and CaV1.1 antibodies were significant for all three muscles. However, the variability in content between the three muscles or individual fibers was much greater for Kir6.2 than for CaV1.1. It is suggested that the t-tubular KATP channel content increases as the glycolytic capacity increases and as the oxidative capacity decreases and that the expression of KATP channels may be linked to how often muscles/fibers face metabolic stress.

scholarly journals lncRNA-Six1 Is a Target of miR-1611 that Functions as a ceRNA to Regulate Six1 Protein Expression and Fiber Type Switching in Chicken Myogenesis

Cells ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 243 ◽  
Author(s):  
Manting Ma ◽  
Bolin Cai ◽  
Liang Jiang ◽  
Bahareldin Ali Abdalla ◽  
Zhenhui Li ◽  
...  
Keyword(s):  
Fiber Type ◽  
Muscle Fibers ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Proliferation And Differentiation ◽  
Slow Twitch Muscle ◽  
Fast Twitch Muscle ◽  
Slow Twitch ◽  
Slow Twitch Fibers ◽  
Fast Twitch

Emerging studies indicate important roles for non-coding RNAs (ncRNAs) as essential regulators in myogenesis, but relatively less is known about their function. In our previous study, we found that lncRNA-Six1 can regulate Six1 in cis to participate in myogenesis. Here, we studied a microRNA (miRNA) that is specifically expressed in chickens (miR-1611). Interestingly, miR-1611 was found to contain potential binding sites for both lncRNA-Six1 and Six1, and it can interact with lncRNA-Six1 to regulate Six1 expression. Overexpression of miR-1611 represses the proliferation and differentiation of myoblasts. Moreover, miR-1611 is highly expressed in slow-twitch fibers, and it drives the transformation of fast-twitch muscle fibers to slow-twitch muscle fibers. Together, these data demonstrate that miR-1611 can mediate the regulation of Six1 by lncRNA-Six1, thereby affecting proliferation and differentiation of myoblasts and transformation of muscle fiber types.

Cross-reinnervated motor units in cat muscle. I. Flexor digitorum longus muscle units reinnervated by soleus motoneurons

1985 ◽  
Vol 54 (4) ◽  
pp. 818-836 ◽  
Author(s):  
R. P. Dum ◽  
M. J. O'Donovan ◽  
J. Toop ◽  
R. E. Burke
Keyword(s):  
Muscle Fibers ◽  
Motor Units ◽  
Muscle Fiber Types ◽  
Type I ◽  
Fiber Types ◽  
Glycogen Depletion ◽  
Flexor Digitorum Longus ◽  
Wet Weight ◽  
Flexor Digitorum ◽  
Individual Motor

The properties of flexor digitorum longus (FDL) muscles and of individual motor units were studied in cats 30-50 wk after self-reinnervation by FDL motoneurons (FDL----FDL) or cross-reinnervation by soleus (SOL) motoneurons (SOL----FDL). Individual motor units were functionally isolated by intracellular recording and stimulation of identified SOL alpha-motoneurons. Glycogen-depletion methods permitted histochemical study of muscle fibers belonging to physiologically characterized muscle units. The observations were compared with data from normal cat FDL muscles and motor units (27). Intentionally self-reinnervated FDL muscles (FDL----FDL; n = 5) were normal in size and wet weight. FDL----FDL motor units could be classified into the same physiological categories found in normal FDL [types: fast contracting, fatigable (FF), fast contracting, fatigue resistant (FR), and slow (S); n = 24], with approximately the same proportions as normal. The histochemical muscle fiber types associated with these categories were also qualitatively normal although there was evidence of marked distortion of the normal histochemical mosaic. These data confirm other studies of self-reinnervation and suggest that self-reinnervation can produce complete interconversion of muscle fiber types. Cross-reinnervation of FDL muscle by SOL motoneurons (SOL----FDL; n = 12) produced muscles that were smaller (about half the normal wet weight) and more red than normal. SOL----FDL muscle contracted more slowly than normal or FDL----FDL muscles and had much higher proportions of histochemical type I muscle fibers. In those SOL----FDL muscles, in which little or no unwanted self-reinnervation could be demonstrated, greater than 95% of the muscle fibers were type I. Forty-one individual motor units in SOL----FDL muscles were isolated by intracellular penetration in functionally identified SOL alpha-motoneurons. Their muscle units were all type S by physiological criteria (absence of "sag" in unfused tetani and marked resistance to fatigue). SOL----FDL muscle units had contraction times and fatigue properties that were essentially identical to those of type S units in the normal FDL. All of the seven units, successfully studied by glycogen depletion, exhibited histochemical type I fibers. SOL motoneurons that innervated FDL muscle units had slightly shorter afterhyperpolarization durations than normal SOL cells, but axonal conduction velocities were normal.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Quantitative electrophoretic analysis of myosin heavy chains in single muscle fibers

2001 ◽  
Vol 90 (5) ◽  
pp. 1927-1935 ◽  
Author(s):  
Boris A. Tikunov ◽  
H. Lee Sweeney ◽  
Lawrence C. Rome
Keyword(s):  
Muscle Fibers ◽  
Electrophoretic Analysis ◽  
Single Fiber ◽  
Fiber Types ◽  
Single Muscle ◽  
Myosin Heavy Chains ◽  
Single Fibers ◽  
Heavy Chains ◽  
Cross Bridges ◽  
Whole Muscle

To better understand the molecular basis of the large variation in mechanical properties of different fiber types, there has been an intense effort to relate the mechanical and energetic properties measured in skinned single fibers to those of their constituent cross bridges. There is a significant technical obstacle, however, in estimating the number of cross bridges in a single fiber. In this study, we have developed a procedure for extraction and quantification of myosin heavy chains (MHCs) that permits the routine and direct measurement of the myosin content in single muscle fibers. To validate this method, we also compared MHC concentration measured in single fibers with the MHC concentration in whole fast-twitch (psoas and gracilis) and slow-twitch (soleus) muscles of rabbit. We found that the MHC concentration in intact psoas (184 μM) was larger than that in soleus (144 μM), as would be expected from their differing mitochondrial content and volume of myofibrils. We obtained excellent agreement between MHC concentration measured at the single fiber level with that measured at the whole muscle level. This not only verifies the efficacy of our procedure but also shows that the difference in concentration at the whole muscle level simply reflects the concentration differences in the constituent fiber types. This new procedure should be of considerable help in future attempts to determine kinetic differences in cross bridges from different fiber types.

scholarly journals In Vivo Studies on Fast and Slow Muscle Fibers in Cat Extraocular Muscles

1966 ◽  
Vol 49 (6) ◽  
pp. 1177-1198 ◽  
Author(s):  
PAUL BACH-y-RITA ◽  
FUMIO ITO
Keyword(s):  
Extraocular Muscle ◽  
Muscle Fibers ◽  
Nerve Fibers ◽  
Slow Muscle ◽  
In Vivo Studies ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Conduction Velocities ◽  
Frequency Of Stimulation

In anesthetized in vivo preparations, responses of two types of extraocular muscle fibers have been studied. The small, multiply innervated slow fibers have been shown to be capable of producing propagated impulses, and thus have been labeled slow multi-innervated twitch fibers. Fast and slow multi-innervated twitch fibers are distinguished by impulse conduction velocities, by ranges of membrane potentials, by amplitudes and frequencies of the miniature end plate potentials, by responses to the intravenous administration of succinylcholine, by the frequency of stimulation required for fused tetanus, and by the velocities of conduction of the nerve fibers innervating each of the muscle fiber types.

scholarly journals CHANGES IN ENZYME ACTIVITIES OF VARIOUS MUSCLE FIBER TYPES IN RAT INDUCED BY DIFFERENT EXERCISES

1969 ◽  
Vol 17 (9) ◽  
pp. 601-607 ◽  
Author(s):  
K. KOWALSKI ◽  
E. E. GORDON ◽  
A. MARTINEZ ◽  
J. ADAMEK
Keyword(s):  
Endurance Exercise ◽  
Enzyme Activities ◽  
Succinic Dehydrogenase ◽  
Weight Lifting ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Phosphorylase Activity ◽  
Succinic Dehydrogenase Activity ◽  
Whole Muscle ◽  
Enzyme Patterns

Mutability of enzyme activities (phosphorylase, succinic dehydrogenase, cytochrome oxidase) of red and white fibers was studied in rat quadriceps subjected to normal physiologic chronic exercises. A rise in phosphorylase activity was found in weight lifting and to a greater extent in running rats when muscle was taken as a whole, but both exercises resulted in equal increments for succinic dehydrogenase and cytochrome oxydase activities. Intraregional comparisons, however, revealed the greatest relative rise of succinic dehydrogenase activity in those fibers that were regarded as predominantly anaerobic in type. This effect was seen only with running and not with weight lifting. Statistically unproved but frequently observed after running in some of the preparations was a rise of phosphorylase activity in red fibers, although to a lesser degree than in white. Thus, in contrast to the dichotomy apparent in electrophysiologic events in nerve and its dependent muscle, metabolic demands may alter what is regarded normally as fixed fiber enzyme patterns. Whole muscle cannot be studied as a biochemical entity because of diverse regional responses to the same stimuli. Endurance exercise (running) and brief, forceful exercise (weight lifting) produced quantitatively different regional changes in succinic dehydrogenase and probably in phosphorylase activities.

scholarly journals Metabolic and morphometric profile of muscle fibers in chronic hemodialysis patients

2012 ◽  
Vol 112 (1) ◽  
pp. 72-78 ◽  
Author(s):  
Michael I. Lewis ◽  
Mario Fournier ◽  
Huiyuan Wang ◽  
Thomas W. Storer ◽  
Richard Casaburi ◽  
...  
Keyword(s):  
Muscle Fiber ◽  
Muscle Fibers ◽  
Exercise Intolerance ◽  
Maintenance Hemodialysis ◽  
Muscle Fiber Types ◽  
Vastus Lateralis Muscle ◽  
Type I ◽  
Fiber Types ◽  
Dense Matrix ◽  
Individual Fiber

Muscle weakness and effort intolerance are common in maintenance hemodialysis (MHD) patients. This study characterized morphometric, histochemical, and biochemical properties of limb muscle in MHD patients compared with controls (CTL) with similar age, gender, and ethnicity. Vastus lateralis muscle biopsies were obtained from 60 MHD patients, 1 day after dialysis, and from 21 CTL. Muscle fiber types and capillaries were identified immunohistochemically. Individual muscle fiber cross-sectional areas (CSA) were quantified. Individual fiber oxidative capacities were determined (microdensitometric assay) to measure succinate dehydrogenase (SDH) activity. Mean CSAs of type I, IIA, and IIX fibers were 33, 26, and 28% larger in MHD patients compared with CTL. SDH activities for type I, IIA, and IIX fibers were reduced by 29, 40, and 47%, respectively, in MHD. Capillary to fiber ratio was increased by 11% in MHD. The number of capillaries surrounding individual fiber types were also increased (type I: 9%; IIA: 10%; IIX: 23%) in MHD patients. However, capillary density (capillaries per unit muscle fiber area) was reduced by 34% in MHD patients, compared with CTL. Ultrastuctural analysis revealed swollen mitochondria with dense matrix in MHD patients. These results highlight impaired oxidative capacity and capillarity in MHD patients. This would be expected to impair energy production as well as substrate and oxygen delivery and exchange and contribute to exercise intolerance. The enlarged CSA of muscle fibers may, in part, be accounted for by edema. We speculate that these changes contribute to reduce limb strength in MHD patients by reducing specific force.

Expression of the Na+/Ca2+exchanger in skeletal muscle

2001 ◽  
Vol 280 (1) ◽  
pp. C146-C154 ◽  
Author(s):  
Bodvaël Fraysse ◽  
Thierry Rouaud ◽  
Marie Millour ◽  
Josiane Fontaine-Pérus ◽  
Marie-France Gardahaut ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fibers ◽  
Cellular Level ◽  
Postnatal Life ◽  
Fiber Types ◽  
Developmentally Regulated ◽  
Protein Levels ◽  
Isoform Expression ◽  
Fast Twitch

The expression of the Na+/Ca2+ exchanger was studied in differentiating muscle fibers in rats. NCX1 and NCX3 isoform (Na+/Ca2+ exchanger isoform) expression was found to be developmentally regulated. NCX1 mRNA and protein levels peaked shortly after birth. Conversely, NCX3 isoform expression was very low in muscles of newborn rats but increased dramatically during the first 2 wk of postnatal life. Immunocytochemical analysis showed that NCX1 was uniformly distributed along the sarcolemmal membrane of undifferentiated rat muscle fibers but formed clusters in T-tubular membranes and sarcolemma of adult muscle. NCX3 appeared to be more uniformly distributed along the sarcolemma and inside myoplasm. In the adult, NCX1 was predominantly expressed in oxidative (type 1 and 2A) fibers of both slow- and fast-twitch muscles, whereas NCX3 was highly expressed in fast glycolytic (2B) fibers. NCX2 was expressed in rat brain but not in skeletal muscle. Developmental changes in NCX1 and NCX3 as well as the distribution of these isoforms at the cellular level and in different fiber types suggest that they may have different physiological roles.

scholarly journals The effects of aging on biceps brachii muscle fibers: a morphometrical study from biopsies and autopsies

2003 ◽  
Vol 61 (3A) ◽  
pp. 555-560 ◽  
Author(s):  
Ana Cláudia Mattiello-Sverzut ◽  
Leila Chimelli ◽  
Maria Silvia de Assis Moura ◽  
Silvia Teixeira ◽  
José Alberto Mello de Oliveira
Keyword(s):  
Cross Sections ◽  
Biceps Brachii ◽  
Muscle Fibers ◽  
Atpase Reaction ◽  
Fiber Size ◽  
Effects Of Aging ◽  
Sixth Decade ◽  
Morphometrical Study

OBJECTIVES: In order to study the morphology and size of muscle fibers, cross sections of biceps brachii samples from autopsies, up to 9 hours after death, and biopsies of 72 subjects were compared. The subjects aged 13 to 84 years in both sexes. METHODS: The samples obtained from autopsies (n=47) were from subjects with sudden death, or who died after acute disease without evidence of neuromuscular involvement. The biopsies (n=25) were from patients with symptoms suggestive of inflammatory or metabolic myopathy, not confirmed morphologically. The lesser diameter of muscle fibers was measured using the ATPase reaction. RESULTS: Morphological analysis showed that aging changes were present from the sixth decade in autopsies, and consisted of atrophy and/or type-grouping. The statistical models adjusted for females in both autopsies and biopsies were linear straight with no variation in fiber size with increasing age. The models adjusted for males in both groups were quadratic, indicating that age influenced the size of different type fibers. In males type 2 were larger than type 1 fibers, and than fibers in females. CONCLUSIONS: These values might be useful as controls, helping interpretation of changes in fiber size in samples obtained from biopsies and autopsies.

scholarly journals A Histochemical Study of Normal and Denervated Red and White Muscles of the Rat

1958 ◽  
Vol 4 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Vivianne T. Nachmias ◽  
Helen A. Padykula
Keyword(s):  
Adenosine Triphosphatase ◽  
Histochemical Study ◽  
Muscle Fibers ◽  
Succinic Dehydrogenase ◽  
Biceps Femoris ◽  
Fiber Types ◽  
Albino Rat ◽  
Whole Muscle ◽  
Red And White Muscles

The distribution and characterization of the fibers of normal and denervated red and white muscles of the albino rat are reported in this study. Histochemical procedures for succinic dehydrogenase, lipides, adenosinetriphosphatase, esterase, and glycogen were utilized to differentiate muscle fibers, and these methods facilitated the study of the distribution of fiber types within whole muscle. Muscle fibers of the granular type (dark or red fibers) can be clearly distinguished from those with clearer sarcoplasm (light or white fibers) by methods for demonstrating succinic dehydrogenase, lipides, and esterase. The method for adenosine-triphosphatase reveals differences only under the special conditions described in the text. Additional fiber types are described in the cat's diaphragm and in the extrinsic ocular muscles of the rat. Succinic dehydrogenase and adenosinetriphosphatase activities of the soleus and biceps femoris were studied 14 days after denervation of these muscles. The histochemical findings are discussed principally in the light of current biochemical knowledge of these enzymes.

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