scholarly journals Human facial muscles: Dimensions, motor endplate distribution, and presence of muscle fibers with multiple motor endplates

1997 ◽  
Vol 249 (2) ◽  
pp. 276-284 ◽  
Author(s):  
Wolfgang Happak ◽  
Ji Liu ◽  
Georg Burggasser ◽  
Amanda Flowers ◽  
Helmut Gruber ◽  
...  
Keyword(s):  
Muscle Fibers ◽  
Motor Endplate ◽  
Motor Endplates ◽  
Facial Muscles

Structure and innervation of the swim bladder musculature in the weakfish, Cynoscion regalis (Teleostei: Sciaenidae)

1982 ◽  
Vol 60 (8) ◽  
pp. 1955-1967 ◽  
Author(s):  
R. Dana Ono ◽  
Stuart G. Poss
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Muscle Fiber ◽  
Muscle Fibers ◽  
Postsynaptic Membrane ◽  
Motor Endplate ◽  
Central Core ◽  
Swim Bladder ◽  
Motor Endplates ◽  
Cynoscion Regalis

The striated swim bladder muscles of the weakfish Cynoscion regalis are deep red in color but cannot be classified histologically as having typical red fibers. The muscle fibers are homogeneous and average 29.6 ± 5.3 μm in diameter, one-fifth the diameter of the adjacent hypaxialis fibers. Each muscle fiber contains thin, ribbonlike myofibrils which are radially arranged around a central core of mitochondria, glycogen, and sarcoplasmic reticulum. Myofibrils are extremely regular in pattern. Triads occur at the Z line. Numerous mitochondria and muscle nuclei are located at the periphery of each muscle fiber. The muscle fibers are multiply innervated with motor endplates distributed along their entire lengths. Well-developed folding of the postsynaptic membrane, not previously reported in fishes, is present at the motor endplate.

scholarly journals Globular and asymmetric acetylcholinesterase in frog muscle basal lamina sheaths.

1986 ◽  
Vol 102 (3) ◽  
pp. 762-768 ◽  
Author(s):  
M Nicolet ◽  
M Pinçon-Raymond ◽  
F Rieger
Keyword(s):  
Basal Lamina ◽  
Acetylcholine Receptors ◽  
Muscle Fibers ◽  
Frog Muscle ◽  
Motor Endplate ◽  
Molecular Forms ◽  
Nonionic Detergent ◽  
Plasmic Membrane ◽  
Triton X

After denervation in vivo, the frog cutaneus pectoris muscle can be led to degenerate by sectioning the muscle fibers on both sides of the region rich in motor endplate, leaving, 2 wk later, a muscle bridge containing the basal lamina (BL) sheaths of the muscle fibers (28). This preparation still contains various tissue remnants and some acetylcholine receptor-containing membranes. A further mild extraction by Triton X-100, a nonionic detergent, gives a pure BL sheath preparation, devoid of acetylcholine receptors. At the electron microscope level, this latter preparation is essentially composed of the muscle BL with no attached plasmic membrane and cellular component originating from Schwann cells or macrophages. Acetylcholinesterase is still present in high amounts in this BL sheath preparation. In both preparations, five major molecular forms (18, 14, 11, 6, and 3.5 S) can be identified that have either an asymmetric or a globular character. Their relative amount is found to be very similar in the BL and in the motor endplate-rich region of control muscle. Thus, observations show that all acetylcholinesterase forms can be accumulated in frog muscle BL.

scholarly journals THE FINE STRUCTURE OF MOTOR ENDPLATE MORPHOGENESIS

1969 ◽  
Vol 42 (1) ◽  
pp. 154-169 ◽  
Author(s):  
A. M. Kelly ◽  
S. I. Zacks
Keyword(s):  
Fine Structure ◽  
Schwann Cells ◽  
Basal Lamina ◽  
Plasma Membranes ◽  
Muscle Cells ◽  
Motor Endplate ◽  
Intercostal Muscle ◽  
Motor Endplates ◽  
Terminal Axon ◽  
Small Muscle

The fine structure of the developing neuromuscular junction of rat intercostal muscle has been studied from 16 days in utero to 10 days postpartum. At 16 days, neuromuscular relations consist of close membrane apposition between clusters of axons and groups of myotubes. Focal electron-opaque membrane specializations more intimately connect axon and myotube membranes to each other. What relation these focal contacts bear to future motor endplates is undetermined. The presence of a group of axons lying within a depression in a myotube wall and local thickening of myotube membranes with some overlying basal lamina indicates primitive motor endplate differentiation. At 18 days, large myotubes surrounded by new generations of small muscle cells occur in groups. Clusters of terminal axon sprouts mutually innervate large myotubes and adjacent small muscle cells within the groups. Nerve is separated from muscle plasma membranes by synaptic gaps partially filled by basal lamina. The plasma membranes of large myotubes, where innervated, simulate postsynaptic membranes. At birth, intercostal muscle is composed of separate myofibers. Soleplate nuclei arise coincident with the peripheral migration of myofiber nuclei. A possible source of soleplate nuclei from lateral fusion of small cells' neighboring areas of innervation is suspected but not proven. Adjacent large and small myofibers are mutually innervated by terminal axon networks contained within single Schwann cells. Primary and secondary synaptic clefts are rudimentary. By 10 days, some differentiating motor endplates simulate endplates of mature muscle. Processes of Schwann cells cover primary synaptic clefts. Axon sprouts lie within the primary clefts and are separated from each other. Specific neural control over individual myofibers may occur after neural processes are segregated in this manner.

Motor nerve transplantation

1997 ◽  
Vol 87 (4) ◽  
pp. 615-624 ◽  
Author(s):  
William P. Gray ◽  
Catherine Keohane ◽  
William O. Kirwan
Keyword(s):  
Motor Nerve ◽  
Nerve Fibers ◽  
Nerve Graft ◽  
Motor Endplate ◽  
Denervated Muscle ◽  
Response Curves ◽  
Motor Endplates ◽  
Content Type ◽  
Nerve Transplantation ◽  
The Right

✓ The motor nerve transplantation (MNT) technique is used to transfer an intact nerve into a denervated muscle by harvesting a neurovascular pedicle of muscle containing motor endplates from the motor endplate zone of a donor muscle and implanting it into a denervated muscle. Thirty-six adult New Zealand White rabbits underwent reinnervation of the left long peroneal (LP) muscle (fast twitch) with a motor nerve graft from the soleus muscle (slow twitch). The right LP muscle served as a control. Reinnervation was assessed using microstimulatory single-fiber electromyography (SFEMG), alterations in muscle fiber typing and grouping, and isometric response curves. Neurofilament antibody was used for axon staining. The neurofilament studies provided direct evidence of nerve growth from the motor nerve graft into the adjacent denervated muscle. Median motor endplate jitter was 13 µsec preoperatively, and 26 µsec at 2 months, 29.5 µsec at 4 months, and 14 µsec at 6 months postoperatively (p < 0.001). Isometric tetanic tension studies showed a progressive functional recovery in the reinnervated muscle over 6 months. There was no histological evidence of aberrant reinnervation from any source outside the nerve pedicle. Isometric twitch responses and adenosine triphosphatase studies confirmed the conversion of the reinnervated LP muscle to a slow-type muscle. Acetylcholinesterase studies confirmed the presence of functioning motor endplates beneath the insertion of the motor nerve graft. It is concluded that the MNT technique achieves motor reinnervation by growth of new nerve fibers across the pedicle graft into the recipient muscle.

Repression of myosin isoforms in developing and denervated skeletal muscle fibers originates near motor endplates

2000 ◽  
Vol 217 (1) ◽  
pp. 50-61 ◽  
Author(s):  
Benjamin W. C. Rosser ◽  
Cindy M. Farrar ◽  
Natasha K. Crellin ◽  
Linda B. Andersen ◽  
Everett Bandman
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fibers ◽  
Myosin Isoforms ◽  
Motor Endplates ◽  
Skeletal Muscle Fibers

The Development of Facial Muscles and Nerves in Relation to the Möbius Syndrome

1981 ◽  
Vol 89 (6) ◽  
pp. 903-906 ◽  
Author(s):  
Bruce M. Carlson
Keyword(s):  
Facial Paralysis ◽  
Muscle Fibers ◽  
Experimental Animals ◽  
Early Stages ◽  
Facial Muscles ◽  
Möbius Syndrome ◽  
Pathologic Findings ◽  
Facial Nerves ◽  
Motor Nerves

This paper discusses descriptive and experimental embryologic material that may be of relevance in understanding the pathologic findings of, and attempting treatment of, congenital facial paralysis. The embryology of the human facial nerves and muscles is described. In experimental animals muscles undergo early stages of morphogenesis and differentiation in the absence of nerves and then undergo gradual atrophy. In the absence of muscle fibers, the bulk of embryonic motor nerves that would normally innervate the muscle die.

Interleukin-1 expression in normal motor endplates and muscle fibers showing neurogenic changes

1997 ◽  
Vol 94 (3) ◽  
pp. 272-279 ◽  
Author(s):  
Fran&#x000E7;ois-J&#x000E9;r&#x000F Authier ◽  
B&#x000E9;n&#x000E9;dicte Chazaud ◽  
Chokhri Mhiri ◽  
Marie-Christine Eliezer-Vanerot ◽  
Fran&#x000E7;oise Poron ◽  
...  
Keyword(s):  
Interleukin 1 ◽  
Muscle Fibers ◽  
Motor Endplates

scholarly journals Motor nerve transplantation

1999 ◽  
Vol 7 (3) ◽  
pp. E7
Author(s):  
William P. Gray ◽  
Catherine Keohane ◽  
William O. Kirwan
Keyword(s):  
Motor Nerve ◽  
Nerve Fibers ◽  
Nerve Graft ◽  
Motor Endplate ◽  
Denervated Muscle ◽  
Response Curves ◽  
Motor Endplates ◽  
Nerve Transplantation ◽  
Isometric Twitch ◽  
The Right

The motor nerve transplantation (MNT) technique is used to transfer an intact nerve into a denervated muscle by harvesting a neurovascular pedicle of muscle containing motor endplates from the motor endplate zone of a donor muscle and implanting it into a denervated muscle. Thirty-six adult New Zealand White rabbits underwent reinnervation of the left long peroneal (LP) muscle (fast twitch) with a motor nerve graft from the soleus muscle (slow twitch). The right LP muscle served as a control. Reinnervation was assessed using microstimulatory single-fiber electromyography (SFEMG), alterations in muscle fiber typing and grouping, and isometric response curves. Neurofilament antibody was used for axon staining. The neurofilament studies provided direct evidence of nerve growth from the motor nerve graft into the adjacent denervated muscle. Median motor endplate jitter was 13 μsec preoperatively, and 26 μsec at 2 months, 29.5 μsec at 4 months, and 14 μsec at 6 months postoperatively (p < 0.001). Isometric tetanic tension studies showed a progressive functional recovery in the reinnervated muscle over 6 months. There was no histological evidence of aberrant reinnervation from any source outside the nerve pedicle. Isometric twitch responses and adenosine triphosphatase studies confirmed the conversion of the reinnervated LP muscle to a slow-type muscle. Acetylcholinesterase studies confirmed the presence of functioning motor endplates beneath the insertion of the motor nerve graft. It is concluded that the MNT technique achieves motor reinnervation by growth of new nerve fibers across the pedicle graft into the recipient muscle.

Mitochondrial Changes in Choline-Deficient Rat Myocardium

1968 ◽  
Vol 26 ◽  
pp. 112-113
Author(s):  
F. G. Zaki
Keyword(s):  
Muscle Fibers ◽  
Liver Mitochondria ◽  
Ultrastructural Changes ◽  
Choline Deficiency ◽  
Nutritional Disorder ◽  
Low Protein ◽  
Structural Abnormalities ◽  
Cross Striation ◽  
Pericardial Edema ◽  
Myocardial Lesions

Choline-deficiency was induced in Holtzman young rats of both sexes by feeding them a high fat - low protein diet.Preliminary studies of the ultrastructural changes in the myocardium of these animals have been recently reported from this laboratory. Myocardial lesions first appeared in the form of intraventricular mural thrombi, loss of cross striation of muscle fibers and focal necrosis of muscle cells associated with interstitial myocarditis. Prolonged choline-deficiency induced cardiomegaly associated with pericardial edema.During the early phase of this nutritional disorder, heart mitochondria - despite of not showing any swelling similar to that usually encountered in liver mitochondria of the same animal - ware the most ubiquitous site of marked structural abnormalities. Early changes in mitochondria appeared as vacuolation, disorganization, disruption and loss of cristae. Degenerating mitochondria were often seen quite enlarged and their matrix was replaced by whorls of myelin figures resembling lysosomal structures especially where muscle fibers were undergoing necrosis. In some areas, mitochondria appeared to be unusually clumped together where some contained membranelined vacuoles and others enclosed dense bodies and granular inclusions.

Sign in / Sign up

Export Citation Format

Share Document