scholarly journals REGENERATION OF PIGEON FAST AND SLOW MUSCLE FIBER TYPES AFTER PARTIAL EXCISION AND MINCING

1974 ◽  
Vol 61 (2) ◽  
pp. 414-426 ◽  
Author(s):  
Robert S. Hikida ◽  
Joseph A. Lombardo
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Slow Muscle ◽  
Oxidative Enzymes ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Slow Slip ◽  
Ultrastructural Examination ◽  
Cross Sectional ◽  
Ultrastructural Studies ◽  
The Matrix

The pigeon's metapatagialis muscles, containing fast fibers in two slips and slow fibers in another slip, were excised for a third of their length, minced, and replaced into their previous sites. After regeneration, the pattern of fiber types and their ATPase and oxidative enzymes were examined histochemically. Ultrastructural examination was carried out on the fast fibers. After 4–17 wk the muscles had regenerated into patterns histochemically similar to the controls only within the slip containing fast fibers. The slow slip was much less regenerated, and had a histochemically embryonic composition. Fiber types were characterized and their cross-sectional areas measured, and the degree of atrophy was greatest in the large fast fibers and the slow fibers. Ultrastructural studies revealed a number of alterations of the mitochondria, including dense and light areas in the matrix and an altered pattern of the cristae into parallel tubular or vesicular aggregations. Other changes included dilated sarcoplasmic reticulum, myofibril disorganization, and a compaction of filaments. The slow fibers were thought to be slower in their regeneration rates because of the pattern of multiple innervation's producing a more complex regenerative pattern.

scholarly journals miR-206 enforces a slow muscle phenotype

2020 ◽  
Vol 133 (15) ◽  
pp. jcs243162
Author(s):  
Kristen K. Bjorkman ◽  
Martin G. Guess ◽  
Brooke C. Harrison ◽  
Michael M. Polmear ◽  
Angela K. Peter ◽  
...  
Keyword(s):  
Knockout Mice ◽  
Striated Muscle ◽  
Systolic Dysfunction ◽  
Slow Muscle ◽  
Functional Adaptation ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Sexual Dimorphisms ◽  
Pathological Conditions ◽  
Post Transcriptional Regulation

ABSTRACTStriated muscle is a highly specialized collection of tissues with contractile properties that vary according to functional needs. Although muscle fiber types are established postnatally, lifelong plasticity facilitates stimulus-dependent adaptation. Functional adaptation requires molecular adaptation, which is partially provided by miRNA-mediated post-transcriptional regulation. miR-206 is a muscle-specific miRNA enriched in slow muscles. We investigated whether miR-206 drives the slow muscle phenotype or is merely an outcome. We found that miR-206 expression increases in both physiological (including female sex and endurance exercise) and pathological conditions (muscular dystrophy and adrenergic agonism) that promote a slow phenotype. Consistent with that observation, the slow soleus muscle of male miR-206-knockout mice displays a faster phenotype than wild-type mice. Moreover, left ventricles of male miR-206 knockout mice have a faster myosin profile, accompanied by dilation and systolic dysfunction. Thus, miR-206 appears to be necessary to enforce a slow skeletal and cardiac muscle phenotype and to play a key role in muscle sexual dimorphisms.

scholarly journals Morphological peculiarities of neuromuscular junctions among different fiber types: Effect of exercise

2017 ◽  
Vol 27 (3) ◽  
Author(s):  
Teet Seene ◽  
Maria Umnova ◽  
Priit Kaasik
Keyword(s):  
Axon Terminal ◽  
Neuromuscular Junctions ◽  
Muscle Fibers ◽  
Cross Sectional Area ◽  
Fiber Types ◽  
Sectional Area ◽  
Cross Sectional ◽  
Thin Sections ◽  
Axon Terminals ◽  
Ultrastructural Studies

The aim of our research was to examine whether there are differences in the morphology of neuromuscular junctions of different types of muscle fibers in rodents, and after their adaptation to six weeks endurance exercise training. After 5-day acclimation, Wistar rats were subjected to run with the speed 35 m/min during 6 week, 5 days per week and the training volume reached 60 min per day. Muscle samples for ultrastructural studies were fixed, dehydrated and embedded in Epon-812. Ultra-thin sections were cut from longitudinally and transversely oriented blocs, using 4 blocks from each animal. The area of axon terminals on fast- twitch fibers is 1.5 time large (p<0.001) and the perimeter of terminals is 1.7 time large in comparison with slow- twitch oxidative fibers (p<0.001) in control group. There are correlation between cross-sectional area of different muscle fibers and length of axon terminals (r=0.72), between cross-sectional area and with of axon terminal (r=-0.62), and between turnover rate of contractile proteins and length of axon terminal (r=0.75). Fast remodeling of synapse on oxidative and oxidative-glycolytic muscle fibers during endurance training seems to guarantees the intensive renewal of the structures of muscle fibers with higher oxidative capacity.

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 OR-043 UPRmt and mitophagy are selectively activated depending on muscle fiber types in insulin resistant rats

2018 ◽  
Vol 1 (2) ◽  
Author(s):  
Can Li ◽  
Nan Li ◽  
Yong Zhang
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Quality Control ◽  
Muscle Fiber ◽  
Slow Muscle ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Mitochondrial Quality Control ◽  
Insulin Resistant ◽  
Related Proteins

Objective To investigate how different skeletal muscle fiber types affect development of insulin resistance, and to explore the role of mitochondrial quality control system, especially mitochondrial unfolded protein response (UPRmt) and mitophagy, in response to metabolic stresses. Methods Male Wistar rats were randomly divided into 2 groups: fed with the normal diet for 8 weeks (Con), and fed with 45% high-fat diet for 8 weeks (IR). Fasting blood glucose (FBG), fasting insulin (FIN) and oral glucose tolerance test (OGTT) were used to identify insulin resistance model. Gastrocnemius (GC), soleus (SOL) and tibialis anterior (TA) muscle were isolated, and RT-qPCR was used to determine the expression of Myhc7, Myhc4. Oxygraph-2k was used to determine the mitochondrial State 3 (ST3), State 4(ST4) respiration and respiration control rate (RCR). JC-1 probe was used to measure mitochondrial membrane potential. Western Blot was used to determine the expressions of marker proteins of muscle fiber types (Myhc4, Myhc7), UPRmt related proteins (Hsp60, Hsp70) and mitophagy related proteins (Pink1, LC3). Results Compared with Con group, in IR group, FBG (7.1±1.27 vs. 5.4±0.43，p＜0.05), FIN (19.4±5.2 vs. 31.6±6.7，p＜0.05 ) and OGTT (area under the curve, about 31.7% increases, p＜0.05) were significantly higher. Myhc4 mRNA (relative fold about 55.6% increases) and protein expression (about 33.9% increases, p＜0.05) were significantly higher in GC. Myhc4 protein expression was significantly higher in GC (about 60.5% increases, p＜0.05). While Myhc7 mRNA expression (about 51.1% decreases, p＜0.05) was significantly lower in SOL. Compared with Con group, in IR group, mitochondrial RCR in SOL muscle was significantly lower (about 22.5% decreases, p＜0.05). Furthermore, the expression of HSP60 (about 36.7% increases，p＜0.05) and HSP70 (about 44.3% increases，p＜0.05) was significantly higher in TA muscle, while the expression of Parkin (about 18.8% decreases，p＜0.05) and the ratio between LC3 II/I (about 26.0% decreases，p＜0.05)expression in SOL muscle were significantly lower. Conclusions In this study, we found that the percentage of fast muscle fibers was elevated in IR skeletal muscle, which were supported by increased Myhc4 and decreased Myhc7 level. Impaired mitochondrial function was only observed in slow muscle as inhibition of mitochondrial respiration. As marker of UPRmt, HSP60/70 were specifically activated in fast muscle in IR, while mitophagy-related proteins were specifically increased in slow muscle. These results indicate that mitochondrial quality control systems are selectively activated to recover mitochondrial functions depending on muscle fiber types in insulin resistant rat.

Relationship of membrane systems in muscle to isomyosin content

1987 ◽  
Vol 65 (4) ◽  
pp. 598-605 ◽  
Author(s):  
Brenda R. Eisenberg ◽  
David J. Dix ◽  
Zhaoying W. Lin ◽  
Mary P. Wenderoth
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Skeletal Muscles ◽  
Protein Isoforms ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Membrane Systems ◽  
Junctional Coupling ◽  
Cardiac Muscles ◽  
Relationship Of ◽  
T System

The structures and functions of the various subdivisions of the membrane systems of muscle are reviewed. Morphometric data have been recalculated using functional definitions of the membranes as identified by their proteins. Thus, the junctional coupling between the sarcoplasmic reticulum and T system is separated from the remaining longitudinal sarcoplasmic reticulum that bears the calcium ATPase protein. In addition, the morphometry of the membrane systems is related to the various muscle fiber types as defined histochemically and by protein isoforms. The relation of isomyosin type and membrane quantities are compared for guinea pig, chicken, frog, and lobster skeletal muscles and rat and rabbit cardiac muscles. Fiber plasticity is considered in terms of the mixing and matching of amounts and kinds of membranes and proteins.

Qualitatively different cross-bridge attachments in fast and slow muscle fiber types

2009 ◽  
Vol 385 (1) ◽  
pp. 44-48 ◽  
Author(s):  
Stefan Galler ◽  
Oleg Andruchov ◽  
Gabriela M.M. Stephenson ◽  
D. George Stephenson
Keyword(s):  
Muscle Fiber ◽  
Slow Muscle ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Fast And Slow Muscle ◽  
Cross Bridge

Motor units and histochemistry in rat lateral gastrocnemius and soleus muscles: evidence for dissociation of physiological and histochemical properties after reinnervation

1987 ◽  
Vol 57 (4) ◽  
pp. 921-937 ◽  
Author(s):  
M. J. Gillespie ◽  
T. Gordon ◽  
P. R. Murphy
Keyword(s):  
Motor Unit ◽  
Muscle Fibers ◽  
Motor Units ◽  
Slow Muscle ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Lateral Gastrocnemius ◽  
Fast And Slow Muscle ◽  
Individual Muscle ◽  
Significant Change

A reexamination of the question of specificity of reinnervation of fast and slow muscle was undertaken using the original "self" nerve supply to the fast lateral gastrocnemius (LG) and slow soleus muscles in the rat hindlimb. This paradigm takes advantage of the unusual situation of a common nerve branch, which supplies both a fast and slow muscle, and of the opportunity to keep the reinnervating nerve in its normal position. In addition it provides a test of the effects of cross-reinnervation among muscles of the same functional group. The properties of soleus and LG muscles and of individual muscle units were characterized in normal rats and in rats 4-14 mo after cutting the lateral gastrocnemius-soleus (LGS) nerve and suture of the proximal stump to the dorsal surface of the LG muscle. Individual muscle units were functionally isolated by stimulation of single motor axons to LG or soleus muscle contained in teased filaments in the L4 and L5 ventral roots. Motor units were classified as fast contracting fatiguable (FF), fast contracting fatigue resistant (FR), and slow (S) on the basis of criteria described in the cat by Burke et al. and applied to rat muscle units by Gillespie et al. Muscle fibers were classified as fast glycolytic (FG), fast oxidative glycolytic (FOG), and slow oxidative (SO) on the basis of histochemical staining for myosin ATPase, nicotinamide-adenine dinucleotide diaphorase (NADH-D), and alpha-glycerophosphate (alpha-GPD). Reinnervated muscles developed less force and weighed less in accordance with having fewer than normal motor units and having lost denervated muscle fibers. Normal LG contained a small proportion of S-type motor units (9%), whereas the majority (80%) of control soleus units were S type. After reinnervation, each muscle contained similar proportions of fast and slow motor units with S-type units constituting 30% of units in both muscles. When compared with the normal motor-unit sample, there was no significant change in average twitch and tetanic force in reinnervated muscles for each type of motor unit. However, the range within each type was greater, and there was considerable overlap between types. Twitch contraction time was inversely correlated with force in normal and reinnervated muscles as shown previously in self- and cross-reinnervated LGS in the cat. Changes in proportions of motor units in reinnervated LG were accompanied by corresponding changes in histochemical muscle types. This contrasted with reinnervated soleus in which the proportion of muscle fiber types was not significantly changed from normal despite significant change in motor-unit proportions.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals miR-206 Enforces a Slow Muscle Phenotype

2019 ◽  
Author(s):  
Kristen K. Bjorkman ◽  
Martin G. Guess ◽  
Brooke C. Harrison ◽  
Michael M. Polmear ◽  
Angela K. Peter ◽  
...  
Keyword(s):  
Striated Muscle ◽  
Systolic Dysfunction ◽  
Slow Muscle ◽  
Functional Adaptation ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Wild Type ◽  
Sexual Dimorphisms ◽  
Male Specific ◽  
Post Transcriptional Regulation

AbstractStriated muscle is a highly specialized collection of tissues with contractile properties varying according to functional needs. Although muscle fiber types are established postnatally, lifelong plasticity facilitates stimulus-dependent adaptation. Functional adaptation requires molecular adaptation, partially provided by miRNA-mediated post-transcriptional regulation. miR-206 is a muscle-specific miRNA enriched in slow muscles. We investigated whether miR-206 drives the slow muscle phenotype or is merely an outcome. We found that miR-206 expression increases in both physiologic (including female sex and endurance exercise) and pathologic conditions that promote a slow phenotype. Consistent with that observation, the slow soleus muscle of male miR-206 knockout mice displays a faster phenotype than wild-type mice. Moreover, their left ventricles have a faster myosin profile accompanied by male-specific dilation and systolic dysfunction. Thus, miR-206 appears necessary to enforce a slow skeletal and cardiac muscle phenotype and to play a key role in muscle sexual dimorphisms.

Changes in satellite cell mitotic activity during acute period of unilateral diaphragm denervation

1994 ◽  
Vol 77 (3) ◽  
pp. 1128-1134 ◽  
Author(s):  
L. E. Gosselin ◽  
G. Brice ◽  
B. Carlson ◽  
Y. S. Prakash ◽  
G. C. Sieck
Keyword(s):  
Mitotic Activity ◽  
Satellite Cell ◽  
Muscle Fiber ◽  
Muscle Injury ◽  
Cross Sectional Area ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Sectional Area ◽  
Cross Sectional ◽  
Acute Period

The acute period of unilateral diaphragm denervation (DNV) is associated with increases in cell mitotic activity, protein synthesis, and muscle fiber hypertrophy. Our purpose was to determine whether acute unilateral diaphragm DNV is associated with changes in muscle isometric contractile properties, cross-sectional area of different muscle fiber types, mitotic activity of muscle fiber satellite cells, and muscle fiber ultrastructural properties indicative of injury. Adult male Fischer 344 rats underwent a right phrenicotomy, and DNV and intact (INT) hemidiaphragms were studied 72 h later. DNV hemidiaphragm displayed a significant decline in maximal isometric force (8.7 vs. 24.3 N/cm2) and a prolonged time to peak twitch force (47.8 vs. 37.5 ms) and time to half relaxation (72.3 vs. 44.3 ms) compared with INT contralateral hemidiaphragm (P < 0.05). DNV resulted in a significant increase in cross-sectional area of types I (33%), IIa (35%), and IIb (28%) fibers relative to INT hemidiaphragm (P < 0.05). Satellite cell mitotic activity (assessed by incorporation of bromodeoxyuridine) was approximately 5.5 times greater in DNV than in INT muscle (DNV 25.0 +/- 3.8, INT 4.5 +/- 1.4 labeled satellite cell nuclei/1,000 nuclei; P < 0.05). Ultrastructural examination of electron micrographs revealed alterations in Z-line and sarcomeric structure indicative of muscle injury. Cellular infiltration and segmental necrosis were also noted in some fibers. We conclude that acute unilateral diaphragm DNV results in muscle fiber injury that induces satellite cell activation. We also speculate that the specific force decrement associated with DNV is at least partially the result of muscle injury.

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