Fine structure of red and white muscle fibers and their neuromuscular junctions in the snake fish (Ophiocephalus argus)

1969 ◽  
Vol 1 (2) ◽  
pp. 229-246 ◽  
Author(s):  
Yasuko Nakajima
Keyword(s):  
Fine Structure ◽  
White Muscle ◽  
Neuromuscular Junctions ◽  
Muscle Fibers

Proportion of muscles spindles supplied by skeletofusimotor axons (beta-axons) in peroneus brevis muscle of the cat

1975 ◽  
Vol 38 (6) ◽  
pp. 1390-1394 ◽  
Author(s):  
F. Emonet-Denand ◽  
Y. Laporte
Keyword(s):  
Neuromuscular Junctions ◽  
Muscle Fibers ◽  
Repetitive Stimulation ◽  
Motor Axon ◽  
Dynamic Sensitivity ◽  
Conduction Velocities ◽  
Peroneus Brevis ◽  
Stimulation Of

Of 32 cat peroneus brevis spindles, 23 (72%) were found to be supplied by a least 1 skeletofusimotor or beta-axon. A motor axon was identified as skeletofusimotor when repetitive stimulation of it elicited both the contraction of extrafusal muscle fibers and as acceleration of the discharge of primary ending, which persisted after selective block of the neuromuscular junctions of extrafusal muscle fibers. The block was obtained by stimulating single axons at 400-500/s for a few seconds. Of 135 axons supplying extrafusal muscle fibers, 24 (18%) were shown to be beta-axons; 22 beta-axons had conduction velocities ranging from 45 to 75 m/s. All but three beta-axons increased the dynamic sensitivity of primary endings. Beta-innervated spindles may also be supplied by dynamic gamma-axons.

Spontaneous potentials and fine structure of identified frog denervated neuromuscular junctions

Neuroscience ◽  
1980 ◽  
Vol 5 (1) ◽  
pp. 97-108 ◽  
Author(s):  
M.E. Kriebel ◽  
R.B. Hanna ◽  
G.D. Pappas
Keyword(s):  
Fine Structure ◽  
Neuromuscular Junctions

Neuromuscular transmission in dystrophic mice

1977 ◽  
Vol 40 (4) ◽  
pp. 836-843 ◽  
Author(s):  
S. Carbonetto
Keyword(s):  
Neuromuscular Transmission ◽  
Neuromuscular Junctions ◽  
Large Population ◽  
Muscle Fibers ◽  
Dystrophic Muscle ◽  
Quantum Content ◽  
Quantal Size ◽  
Significant Difference ◽  
Release Of Acetylcholine ◽  
Dystrophic Mice

1. Neuromuscular transmission was studied in the extensor digitorum-longus muscle of dystrophic mice (strain 129/ReJ) by means of intracellular recording techniques. 2. In a large population of normal and dystrophic muscle fibers tested, the incidence of transmission failure was about 2% and showed no significant difference between the two groups. 3. Quantal size and quantum content of dystrophic junctions were found to be normal. This was true even of nerve terminal on apparently atrophied muscle fibers. 4. The facilitation ratio at dystrophic junctions was not significantly different from normal. 5. Dystrophic neuromuscular junctions exhibited an abnormality high frequency of giant spontaneous potentials. Application of tetrodotoxin (10(-6) M) and curare (10(-6) M) indicated that these potentials were caused by impulse-independent release of acetylcholine. 6. Neuromuscular transmission in dystrophic mice was found functionally normal and unrelated to the degenerative state of the muscle.

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.

Activation of Embryonic Red and White Muscle Fibers During Fictive Swimming in the Developing Zebrafish

2002 ◽  
Vol 87 (3) ◽  
pp. 1244-1251 ◽  
Author(s):  
Robert R. Buss ◽  
Pierre Drapeau
Keyword(s):  
Muscle Activation ◽  
White Muscle ◽  
Developmental Stages ◽  
Muscle Fibers ◽  
Synaptic Activity ◽  
Body Movements ◽  
Early Developmental ◽  
Whole Cell Recordings ◽  
Myotomal Muscle ◽  
Synaptic Drive

Sub-threshold, motoneuron-evoked synaptic activity was observed in zebrafish embryonic red (ER) and white (EW) muscle fibers paralyzed with a dose of d-tubocurarine insufficient to abolish synaptic activity to determine whether muscle activation was coordinated to produce the undulating body movements required for locomotion. Paired whole-cell recordings revealed a synaptic drive that alternated between ipsilateral and contralateral myotomes and exhibited a rostral-caudal delay in timing appropriate for swimming. Both ER and EW muscle were activated during fictive swimming. However, at the fastest fictive swimming rates, ER fibers were de-recruited, whereas they could be active in isolation of EW fibers at the slowest fictive swimming rates. Prior to hatching, fictive swimming was preceded by a lower frequency, more robust and rhythmic synaptic drive resembling the “coiling” behavior of fish embryos. The motor activity observed in paralyzed zebrafish closely resembled the swimming and coiling behaviors observed in these developing fishes. At the early developmental stages examined in this study, myotomal muscle recruitment and coordination were similar to that observed in adult fishes during swimming. Our results indicate that the patterned activation of myotomal muscle is set from the onset of development.

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