scholarly journals HISTOCHEMICAL DUALITY OF RABBIT INTRAFUSAL FIBERS

1969 ◽  
Vol 17 (5) ◽  
pp. 348-349 ◽  
Author(s):  
ALFRED J. SPIRO ◽  
REBECCA L. BEILIN
Keyword(s):  
Adenosine Triphosphatase ◽  
Muscle Spindles ◽  
Fiber Types ◽  
Rabbit Muscle ◽  
Intrafusal Fibers ◽  
Physiologic Responses

Using the adenosine triphosphatase reaction two histochemically distinct types of intrafusal fibers were demonstrated in rabbit muscle spindles despite morphologic homogeneity of these fibers. This finding, reflecting metabolic differences between these fiber types, is offered as an explanation for the previously unexplained heterogeneity of their physiologic responses.

High incidence of long-chain fibers in spindles of cat superficial lumbrical muscles

1987 ◽  
Vol 57 (4) ◽  
pp. 1050-1059 ◽  
Author(s):  
L. Decorte ◽  
F. Emonet-Denand ◽  
D. W. Harker ◽  
Y. Laporte
Keyword(s):  
Atpase Activity ◽  
Muscle Spindles ◽  
Fiber Types ◽  
Intrafusal Fiber ◽  
Intrafusal Fibers ◽  
Spindle Poles ◽  
Fresh Frozen ◽  
Intrafusal Fiber Types ◽  
Lumbrical Muscles ◽  
Long Chain

Forty-two complete spindle poles of cat superficial lumbrical muscles were analyzed with particular regard to the length and the diameter of intrafusal fiber types. Poles were reconstructed from serial transverse sections of fresh-frozen muscles. The staining module, which was repeated throughout the whole muscle, comprised sections treated for glycogen detection and sections treated for detecting myofibrillar ATPase activity after preincubation at three different pH's (see METHODS). The identification of intrafusal fiber types was essentially based on the ATPase activity of the B region of the intrafusal fibers. Long-chain fibers, i.e., chain fibers that have at least one pole that extends by more than one millimeter beyond the end of the spindle capsule (6), were very commonly observed. Of 42 spindle poles analyzed, 30 (71%) contained at least one long-chain fiber (one in 17 spindle poles, 2 in 11 poles, and 3 in 2 poles). Of 246 poles of chain fibers, 45 (18%) were "long". In four spindles, in which both poles could be completely examined, 10 long-chain fibers were observed. In eight of these, only one pole was long; the opposite pole ended either intracapsularly or at a short distance outside the capsule. Since long-chain fiber poles, presently considered to be among the effectors of static skeletofusimotor (beta) axons, are present in a large proportion of muscle spindles of lumbrical muscles, it would be of particular interest to reevaluate the beta-supply of these muscles by physiological methods.

scholarly journals HISTOCHEMISTRY OF MUSCLE SPINDLES IN SNAKES OF NATRIX SPECIES

1974 ◽  
Vol 22 (9) ◽  
pp. 881-886 ◽  
Author(s):  
D. J. PALLOT ◽  
JANIS TABERNER
Keyword(s):  
Adenosine Triphosphatase ◽  
Muscle Fibers ◽  
Succinic Dehydrogenase ◽  
Muscle Spindles ◽  
Intermediate Level ◽  
The Other ◽  
Intrafusal Fiber ◽  
Intrafusal Fibers ◽  
Low Levels

The muscle spindles of snakes consist of a single intrafusal fiber; in addition to this, two types of spindles are found. We have studied the histochemistry of the snake intrafusal fibers. One type of spindle, the long capsule spindle intrafusal fiber, is characterized by high levels of the enzymes myosin adenosine triphosphatase, succinic dehydrogenase and phosphorylase; the other type, the short capsule spindle intrafusal fiber, is characterized by low levels of myosin adenosine triphosphatase and phosphorylase and an intermediate level of succinic dehydrogenase. The short capsule spindle intrafusal fiber is thus histochemically similar to the tonic extrafusal fibers, whereas the long capsule spindle intrafusal fiber is similar to the twitch extrafusal muscle fibers. The long capsule spindle is concerned mainly with monitoring static length, the short capsule spindle with monitoring changes in length. It is interesting that the histochemical profiles of long and short capsule spindle intrafusal fibers are similar to the mammalian bag and chain fibers, respectively.

scholarly journals Physiological Signs of the Activation of Bag2 and Chain Intrafusal Muscle Fibers of Gastrocnemius Muscle Spindles in the Cat

1998 ◽  
Vol 80 (1) ◽  
pp. 130-142 ◽  
Author(s):  
A. Taylor ◽  
P. H. Ellaway ◽  
R. Durbaba
Keyword(s):  
Gastrocnemius Muscle ◽  
Muscle Fibers ◽  
Muscle Spindles ◽  
Fiber Types ◽  
Dominant Type ◽  
Intrafusal Muscle ◽  
Chance Distribution ◽  
Intrafusal Fibers ◽  
Intrafusal Muscle Fibers ◽  
Prolonged Response

Taylor, A., P. H. Ellaway, and R. Durbaba. Physiological signs of the activation of bag2 and chain intrafusal muscle fibers of gastrocnemius muscle spindles in the cat. J. Neurophysiol. 80: 130–142, 1998. A method is described for identifying the effect of single gamma static (γs) axons on bag2 or chain intrafusal fibers using random (Poisson-distributed) stimuli. The cross-correlogram of the stimuli with the firing of spindle primary afferents took one of three forms. A large, simple, brief response was taken to indicate pure chain fiber activation and a small, prolonged response to indicate pure bag2 activation. A compound response with brief and prolonged components was taken to be a sign of mixed innervation. The correlogram components could be well fitted with lognormal curves. They could also be transformed into curves of gain as a function of frequency, which were convenient for estimating the strength of the effects. In 68 effects of γs axons on Ia afferents, 16 were pure chain, 17 pure bag2, and 35 mixed. This distribution was significantly different ( P < 0.05) from that expected from chance nonspecific innervation of chain and bag2 fibers. Making use of the estimates of the strength of chain and bag2 effects derived from the gain curves, the classification was modified by treating mixed responses that had one effect more than five times stronger than the other as belonging to the dominant type. The distribution was then as follows: chain 16, bag2 28, and mixed 24. This differed very significantly from the prediction of chance distribution ( P < 0.001). This evidence for some degree of specific innervation of chain and bag2 fibers is discussed in relation to previous work and with regard to the ways in which the two fiber types might be used in natural movements.

scholarly journals Muscle Spindles in the Deep Muscles of the Human Neck: A Morphological and Immunocytochemical Study

2003 ◽  
Vol 51 (2) ◽  
pp. 175-186 ◽  
Author(s):  
Jing-Xia Liu ◽  
Lars-Eric Thornell ◽  
Fatima Pedrosa-Domellöf
Keyword(s):  
Fiber Length ◽  
Biceps Brachii ◽  
Muscle Spindles ◽  
Functional Specialization ◽  
Immunocytochemical Study ◽  
Intrafusal Fibers ◽  
Myhc Isoforms ◽  
Nuclear Chain ◽  
Human Muscles ◽  
Lumbrical Muscles

Muscle spindle density is extremely high in the deep muscles of the human neck. However, there is a paucity of information regarding the morphology and immunoreactivity of these muscle spindles. The objective of this study was to investigate the intrafusal fiber content and to assess the myosin heavy chain (MyHC) composition of muscle spindles from human deep neck muscles. In addition to the conventional spindles containing bag1, bag2, and chain fibers (b1b2c spindle), we observed a number of spindles lacking bag1 (b2c spindle) or bag2 (b1c spindle) fibers. Both bag1 and bag2 fibers contained slow tonic MyHCs along their entire fiber length and MyHCI, MyHCIIa, embryonic, and α-cardiac MyHC isoforms along a variable length of the fibers. Fetal MyHC was present in bag2 fibers but not in bag1 fibers. Nuclear chain fibers contained MyHCIIa, embryonic, and fetal isoforms with regional variations. We also compared the present data with our previous results obtained from muscle spindles in human biceps brachii and the first lumbrical muscles. The allotment of numbers of intrafusal fibers and the MyHC composition showed some muscle-related differences, suggesting functional specialization in the control of movement among different human muscles.

Intracellular distribution of succinate dehydrogenase activity in skeletal muscle fibers of geese

1984 ◽  
Vol 62 (2) ◽  
pp. 235-240 ◽  
Author(s):  
H. J. Swatland
Keyword(s):  
Skeletal Muscle ◽  
Succinate Dehydrogenase ◽  
Dehydrogenase Activity ◽  
Adenosine Triphosphatase ◽  
Muscle Fibers ◽  
Fiber Types ◽  
Succinate Dehydrogenase Activity ◽  
Individual Muscle ◽  
Concentric Zone ◽  
Pectoralis Muscles

Samples of iliotibialis anterior and pectoralis muscles were taken from five ganders (Anser domesticus). Serial transverse sections were reacted for succinate dehydrogenase (SDH) and alkali-stable adenosine triphosphatase (ATPase). The distribution of SDH activity within individual muscle fibers was measured with a scanning photometer. In many individual fibers, SDH activity was stronger in the periphery than in the axis. This gradient was steepest (−0.034 ± 0.019 absorbance units per concentric zone of 2 μm diameter measurements) in pectoralis fibers with strong SDH activity. In the pectoralis, radial gradients were correlated with fiber area so that the smallest fibers tended to have the steepest gradients of SDH activity. However, this relationship was reversed in fibers with strong ATPase and weak SDH activity in the iliotibialis anterior, and the largest fibers tended to have the steepest gradients. In all fiber types of both muscles, fibers with greater mean SDH activity tended to have steeper gradients.

scholarly journals Retention of Pax3 Expression in Satellite Cells of Muscle Spindles

2009 ◽  
Vol 58 (4) ◽  
pp. 317-327 ◽  
Author(s):  
Lisa J. Kirkpatrick ◽  
Zipora Yablonka-Reuveni ◽  
Benjamin W.C. Rosser
Keyword(s):  
Skeletal Muscle ◽  
Satellite Cells ◽  
Latissimus Dorsi ◽  
Muscle Spindles ◽  
Latissimus Dorsi Muscle ◽  
Intrafusal Fibers ◽  
Dorsi Muscle ◽  
Avian Muscle ◽  
Anterior Latissimus Dorsi ◽  
Immunohistochemical Techniques

Intrafusal fibers within muscle spindles retain features characteristic of immaturity, unlike the larger and more numerous extrafusal fibers constituting the bulk of skeletal muscle. Satellite cells (SCs), myogenic progenitors, are detected on the surfaces of both intrafusal and extrafusal fibers, but little is known of spindle SCs. We have recently demonstrated that, like their extrafusal counterparts, SCs in muscle spindles of posthatch chickens express paired box transcription factor 7 (Pax7) protein. During vertebrate embryogenesis, myogenic progenitors express both Pax7 and Pax3 proteins. In postnatal mice, Pax3 appears in rare SC subsets, whereas Pax7 is expressed by all SCs within extrafusal fibers. Here we test the hypothesis that Pax3 protein maintains localized expression within SCs of muscle spindles. Immunohistochemical techniques were used to identify SCs by their Pax7 expression within anterior latissimus dorsi muscle excised from posthatch chickens of various ages. A greater percentage of SCs express Pax3 within intrafusal than extrafusal fibers at each age, and the proportion of SCs expressing Pax3 declines with aging. This is the first study to localize Pax3 expression in posthatch avian muscle and within SCs of muscle spindles. We suggest that Pax3-positive SCs are involved in fiber maintenance.

Treatment with beta bungarotoxin blocks muscle spindle formation in fetal rats

Development ◽  
1990 ◽  
Vol 110 (2) ◽  
pp. 483-489
Author(s):  
J. Kucera ◽  
J.M. Waldro
Keyword(s):  
Peripheral Nerves ◽  
Muscle Fibers ◽  
Muscle Spindles ◽  
Myosin Isoforms ◽  
Myosin Heavy Chains ◽  
Heavy Chains ◽  
Intrafusal Fibers ◽  
Intramuscular Nerves ◽  
Fetal Rats ◽  
Intramuscular Nerve

Sensory and motor fibers of peripheral nerves were irreversibly destroyed in fetal rats by administering beta bungarotoxin (BTX) on embryonic day 16 or 17, after assembly of primary myotubes, but before the formation of muscle spindles. Soleus muscles of toxin-treated fetuses and their untreated littermates were removed just prior to birth and were examined by light microscopy of serial transverse sections for the presence of spindles and immunocytochemical expression of several isoforms of myosin heavy chains (MHC). Untreated muscles exhibited numerous spindles that were innervated by branches of intramuscular nerves and contained muscle fibers expressing a slow-tonic MHC isoform characteristic of the intrafusal but not extrafusal fibers. Toxin-treated muscles were devoid of intramuscular nerve bundles and perineurial structures. Encapsulations of muscle fibers resembling spindles were absent and no myotubes expressed the slow-tonic MHC isoform associated with intrafusal fibers in beta BTX-treated muscles. Thus, the assembly of muscle spindles, formation of the spindle capsule, and transformation of undifferentiated myotubes into the intrafusal fibers that contain spindle-specific myosin isoforms all depend on the presence of innervation in prenatal rat muscles.

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