Type and regional diversity in the distribution of myosin heavy chains in chicken intrafusal muscle fibers

1994 ◽  
Vol 240 (4) ◽  
pp. 507-515 ◽  
Author(s):  
Alfred Maier
Keyword(s):  
Muscle Fibers ◽  
Myosin Heavy Chains ◽  
Regional Diversity ◽  
Intrafusal Muscle ◽  
Heavy Chains ◽  
Intrafusal Muscle Fibers

scholarly journals FINE STRUCTURE OF RAT INTRAFUSAL MUSCLE FIBERS

1971 ◽  
Vol 51 (1) ◽  
pp. 83-103 ◽  
Author(s):  
William K. Ovalle
Keyword(s):  
Muscle Fiber ◽  
Muscle Fibers ◽  
Muscle Spindles ◽  
Intrafusal Muscle ◽  
Dense Granules ◽  
Intrafusal Muscle Fibers ◽  
Sarcotubular System ◽  
Nuclear Chain ◽  
T System ◽  
Nuclear Bag

An ultrastructural comparison of the two types of intrafusal muscle fibers in muscle spindles of the rat was undertaken. Discrete myofibrils with abundant interfibrillar sarcoplasm and organelles characterize the nuclear chain muscle fiber, while a continuous myofibril-like bundle with sparse interfibrillar sarcoplasm distinguishes the nuclear bag muscle fiber. Nuclear chain fibers possess well-defined and typical M bands in the center of each sarcomere, while nuclear bag fibers contain ill-defined M bands composed of two parallel thin densities in the center of the pseudo-H zone of each sarcomere. Mitochondria of nuclear chain fibers are larger and more numerous than they are in nuclear bag fibers. Mitochondria of chain fibers, in addition, often contain conspicuous dense granules, and they are frequently intimately related to elements of the sarcoplasmic reticulum (SR). Striking differences are noted in the organization and degree of development of the sarcotubular system. Nuclear bag fibers contain a poorly developed SR and T system with only occasional junctional couplings (dyads and triads). Nuclear chain fibers, in contrast, possess an unusually well-developed SR and T system and a variety of multiple junctional couplings (dyads, triads, quatrads, pentads, septads). Greatly dilated SR cisternae are common features of nuclear chain fibers, often forming intimate associations with T tubules, mitochondria, and the sarcolemma. Such dilatations of the SR were not encountered in nuclear bag fibers. The functional significance of these structural findings is discussed.

scholarly journals Shortening velocity and myosin heavy chains of developing rabbit muscle fibers.

1985 ◽  
Vol 260 (27) ◽  
pp. 14403-14405 ◽  
Author(s):  
P J Reiser ◽  
R L Moss ◽  
G G Giulian ◽  
M L Greaser
Keyword(s):  
Muscle Fibers ◽  
Rabbit Muscle ◽  
Myosin Heavy Chains ◽  
Shortening Velocity ◽  
Heavy Chains

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.

Histochemical Identification of Three Types of Intrafusal Muscle Fibers in the Cat and Monkey Based on the Myosin ATPase Reaction

1972 ◽  
Vol 50 (3) ◽  
pp. 195-202 ◽  
Author(s):  
W. K. Ovalle ◽  
R. S. Smith
Keyword(s):  
Frozen Section ◽  
Muscle Fibers ◽  
Muscle Spindles ◽  
Myosin Atpase ◽  
Stable Form ◽  
Intrafusal Muscle ◽  
Atpase Reaction ◽  
Intrafusal Muscle Fibers ◽  
Alkaline Conditions ◽  
Acid Stable

Serial frozen section of muscle spindles in the lumbrical muscles of the cat and the monkey were tested with a recently described modification of the myosin ATPase reaction (Guth and Samaha 1970. Exp. Neurol 28, 365). This reaction is able to detect acid-stable, alkaline-labile myosin ATPase and acid-labile, alkaline-stable myosin ATPase. The reactions were carried out by preincubation of the sections at pH 10.4 or 4.35 with incubation in a substrate at pH 9.4. In both the cat and the monkey three types of intrafusal muscle fibers could be detected on the basis of their reaction for myosin ATPase. Nuclear bag fibers could be divided into two types: those containing the acid-stable form of myosin ATPase only, and those containing ATPase detectable under both acid and alkaline conditions. Nuclear chain fibers contained the alkaline-stable form of ATPase only.

Origin of intrafusal muscle fibers in the rat

1990 ◽  
Vol 93 (6) ◽  
pp. 567-580 ◽  
Author(s):  
J. Kucera ◽  
J. M. Walro
Keyword(s):  
Muscle Fibers ◽  
Intrafusal Muscle ◽  
Intrafusal Muscle Fibers

scholarly journals Myosin types and fiber types in cardiac muscle. II. Atrial myocardium.

1982 ◽  
Vol 95 (3) ◽  
pp. 838-845 ◽  
Author(s):  
L Gorza ◽  
S Sartore ◽  
S Schiaffino
Keyword(s):  
Right Atrium ◽  
Muscle Fibers ◽  
Interatrial Septum ◽  
Myosin Heavy Chains ◽  
Atrial Myocardium ◽  
Crista Terminalis ◽  
Heavy Chains ◽  
Bovine Heart ◽  
Atrial Muscle ◽  
The Right

Antibodies were produced against myosins isolated from the left atrial myocardium (anti-bAm) and the left ventricular myocardium (anti-bVm) of the bovine heart. Cross-reactive antibodies were removed by cross-absorption. Absorbed anti-bAm and anti-bVm were specific for the myosin heavy chains when tested by enzyme immunoassay combined with SDS gel electrophoresis. Indirect immunofluorescence was used to determine the reactivity of atrial muscle fibers to the two antibodies. Three populations of atrial muscle fibers were distinguished in the bovine heart: (a) fibers reactive with anti-bAm and unreactive with anti-bVm, like most fibers in the left atrium; (b) fibers reactive with both antibodies, especially numerous in the right atrium; (c) fibers reactive with anti-bVm and unreactive with anti-bAm, present only in the interatrial septum and in specific regions of the right atrium, such as the crista terminalis. These findings can be accounted for by postulating the existence of two distinct types of atrial myosin heavy chains, one of which is antigenically related to ventricular myosin. The tendency for fibers labeled by anti-bVm to occur frequently in bundles and their preferential distribution in the crista terminalis, namely along one of the main conduction pathways between the sinus node and the atrioventricular node, and in the interatrial septum, where different internodal tracts are known to converge, suggests that these fibers may be specialized for faster conduction.

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