scholarly journals Hysto-ultrastructure of the facial nerve and mimic muscles in the norm and in the conditions of eхperimental neuropathy

2017 ◽  
Vol 8 (4) ◽  
pp. 569-576
Author(s):  
V. Myhailiuk ◽  
I. Mykhailiuk ◽  
M. Hembarovskyi ◽  
O. Lebid ◽  
K. Duda ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Morphological Changes ◽  
Motor Nerve ◽  
Muscle Fibers ◽  
Small Diameter ◽  
Nerve Fibers ◽  
Residual Effects ◽  
Myelinated Nerve ◽  
Fine Grained ◽  
Argyrophilic Grains

We studied the structural components of the facial nerve in the norm and with cold neuropathy, indicating morphological changes in neuromuscular endings and muscle fibers at 10, 15, 30 and 60 days from the beginning of the simulation of experimental neuropathy, which was caused by local supercooling of the projection portions of the extracranial parts of the facial nerve on the background of the preliminary introduction of Freud’s complete adjuvant. We established that the pathomorphological changes in the endonevral microcirculatory bed have a phase character: the initial spasm (up to 10 days) changes in paralytic vasodilation, and its residual effects remain until the end of the experiment (60 days). Changes in hemomicrocirculation conditions lead to marked disturbances in the structure of myelinic nerve fibers, which have the character of segmental demyelination with signs of delay in axonal transport and reactive restructuring of neuromuscular endings. The change in the metric composition of myelinated nerve fibers is due to an increase in the number of nerve fibers of medium and large diameters (up to 30 days) and small diameter (after 30 days). In different periods of the experiment, a decrease in the branching area of the terminal branches of the motor axon is observed in the nerve cells, local edema of the endonevria, degenerative changes in a part of the nerve fibers develop. Due to the fine-grained decay of the final nerve branches, degeneration of the motor endings took place two weeks after the start of the experiment. Neuropathy for 30 days caused a pronounced inhibition of spotting in the peripheral parts of the motor nerve fibers. After 60 days of experiment, a large number of muscle fibers underwent destructive changes. The size of a significant part of the neuromuscular endings was reduced. In all terms of cold neuropathy, neurolematocytes reacted in the same way: cytoplasm was swollen, argyrophilic grains appeared in the nuclei, fine-grained decay of individual nuclei occurred. 

HISTOMETRIC AND ULTRASTRUCTURAL ORGANIZATION OF THE NERVIMUSCULAR TERMINALS OF SKELETAL MUSCLES AT A HYPOKINESIA

2019 ◽  
pp. 55-63
Author(s):  
Z. M. Yaschyshyn ◽  
S. L. Popel
Keyword(s):  
Skeletal Muscles ◽  
Structural Adjustment ◽  
Muscle Fibers ◽  
Electron Microscopic Examination ◽  
Nerve Fibers ◽  
Ultrastructural Changes ◽  
Ultrastructural Organization ◽  
Electron Microscopic ◽  
Myelinated Nerve ◽  
Male Wistar Rats

The aim: to study the dynamics of histological and ultrastructural changes in muscle fibers and their neuromuscular endings under conditions of prolonged hypokinesia at different stages of ontogenesis. Methods. Studied skeletal muscles and their peripheral nervous apparatus of laboratory male Wistar rats aged 30 to 270 days. The restriction of motor activity was carried out in special canister cells for 30, 60, 90, and 240 days (5 animals for each term). To determine the type of muscle fiber, the Nahlas histochemical method was used, the Kulchitsky method was used to detect myelinated nerve fibers, the Bilshovsky-Gros method and the electron microscopic method to identify neuromuscular endings. Results. The data of histological and electron microscopic examination of skeletal muscle fibers and their neuromuscular endings under conditions of prolonged hypokinesia indicate their regular restructuring during the development of muscles, the formation of their synapses and structures that are associated with them at different stages of ontogenesis. Conclusion. The study provides an in-depth understanding of the relative frequency and nature of the disturbance of the neuromuscular endings during prolonged hypokinesia and its effect on the dynamics of structural adjustment of individual types of muscle fibers in ontogenesis.

HISTOMETRIC AND ULTRASTRUCTURAL ORGANIZATION OF THE NERVIMUSCULAR TERMINALS OF SKELETAL MUSCLES AT A HYPOKINESIA

2019 ◽  
pp. 55-63
Author(s):  
Z. M. Yaschyshyn ◽  
S. L. Popel
Keyword(s):  
Skeletal Muscles ◽  
Structural Adjustment ◽  
Muscle Fibers ◽  
Electron Microscopic Examination ◽  
Nerve Fibers ◽  
Ultrastructural Changes ◽  
Ultrastructural Organization ◽  
Electron Microscopic ◽  
Myelinated Nerve ◽  
Male Wistar Rats

The aim: to study the dynamics of histological and ultrastructural changes in muscle fibers and their neuromuscular endings under conditions of prolonged hypokinesia at different stages of ontogenesis. Methods. Studied skeletal muscles and their peripheral nervous apparatus of laboratory male Wistar rats aged 30 to 270 days. The restriction of motor activity was carried out in special canister cells for 30, 60, 90, and 240 days (5 animals for each term). To determine the type of muscle fiber, the Nahlas histochemical method was used, the Kulchitsky method was used to detect myelinated nerve fibers, the Bilshovsky-Gros method and the electron microscopic method to identify neuromuscular endings. Results. The data of histological and electron microscopic examination of skeletal muscle fibers and their neuromuscular endings under conditions of prolonged hypokinesia indicate their regular restructuring during the development of muscles, the formation of their synapses and structures that are associated with them at different stages of ontogenesis. Conclusion. The study provides an in-depth understanding of the relative frequency and nature of the disturbance of the neuromuscular endings during prolonged hypokinesia and its effect on the dynamics of structural adjustment of individual types of muscle fibers in ontogenesis.

TETRAETHYLAMMONIUM-INDUCED CONTRACTIONS OF FROG'S SKELETAL MUSCLE: II. EFFECTS ON INTRAMUSCULAR NERVE ENDINGS

1967 ◽  
Vol 45 (5) ◽  
pp. 833-844 ◽  
Author(s):  
G. Beaulieu ◽  
G. B. Frank ◽  
F. Inoue
Keyword(s):  
Motor Nerve ◽  
Muscle Fibers ◽  
Electrical Stimulus ◽  
Nerve Fibers ◽  
Ventral Root ◽  
Nerve Endings ◽  
Glass Capillary ◽  
Action Potential Firing ◽  
Low Concentrations ◽  
Potential Firing

By recording simultaneously from muscle fibers and from the ventral root supplying the muscle, it was found that low concentrations of tetraethylammonium (TEA) caused the muscle fibers to fire without antidromic impulses being conducted to the ventral root. Exposing the muscles to higher TEA concentrations induced action potential firing in both the muscle and the ventral root. d-Tubocurarine prevented the muscle fiber activity but did not modify the ventral root firing. The application of a single supramaximal electrical stimulus to the sciatic nerve resulted in an afterdischarge of the muscle fibers either alone or simultaneous with an afterdischarge of fibers in the ventral root. By recording from fine intramuscular motor nerve fibers with extracellular glass capillary microelectrodes while simultaneously recording from the ventral root, it was demonstrated that TEA could cause these fine intramuscular motor nerve fibers to fire without the activity being conducted antidromically to the ventral root. A consideration of the patterns of TEA-induced electrical activity and afterdischarging led to the suggestion that TEA causes these effects by displacing calcium from binding sites on the motor nerve endings, making the latter hyperexcitable and unstable and thereby causing afterdischarging and 'spontaneous' activity.

Conduction blockade in myelinated fibers by gaseous and volatile substances

1991 ◽  
Vol 260 (3) ◽  
pp. R540-R545
Author(s):  
F. G. Carpenter
Keyword(s):  
Partial Pressure ◽  
Large Diameter ◽  
Small Diameter ◽  
Aqueous Solubility ◽  
Nerve Fibers ◽  
Myelinated Nerve ◽  
Molal Volume ◽  
Axon Membrane ◽  
Anesthetic Action ◽  
Solubility Ratio

The minimum ambient partial pressure required to reversibly disrupt conducted responses in myelinated nerve fibers (Pblock) was determined for 11 gases and chloroform. For all but one substance, Pblock was inversely proportional to their nonaqueous solubility; large-diameter fibers were less vulnerable than fibers of small diameter. No "anesthetic" effect was displayed by SF6. At the Pblock for three of the agents, the time for completion of their anesthetic action (tb) was proportional to their lipid-to-aqueous solubility ratio. When the ratio was large, tb was longer than when the ratio was small; blockade became complete after the partial pressure of the agent in the lipid or nonaqueous phase of the axon membrane became equal to Pblock. The access of these substances to an nonaqueous site was neither pH nor frequency dependent, but in the case of SF6 access did appear to be limited by its molal volume.

Amyloid neuropathy simulating lower motor neuron disease

Neurology ◽  
1998 ◽  
Vol 51 (2) ◽  
pp. 600-602 ◽  
Author(s):  
A. Quattrini ◽  
R. Nemni ◽  
B. Sferrazza ◽  
G. Ricevuti ◽  
G. Dell'Antonio ◽  
...  
Keyword(s):  
Axonal Degeneration ◽  
Motor Nerve ◽  
Nerve Biopsy ◽  
Nerve Fibers ◽  
Light Chains ◽  
Myelinated Nerve ◽  
Motor Branch ◽  
Leg Muscles ◽  
Case Diagnosis

We report a 57-year-old man with progressive symmetric weakness and fasciculation affecting the legs. Electromyography revealed fibrillations and neurogenic motor unit potentials in the leg muscles. Biopsy of a motor branch of the obturator nerve revealed axonal degeneration, loss of myelinated nerve fibers, and amyloidosis with deposits of lambda light chains. At 6-month follow-up, the patient manifested sensory and autonomic symptoms, and lambda light chains were first detected in the serum. In this case, diagnosis of amyloidosis remained elusive until motor nerve biopsy.

Action of Tetraethylammonium Chloride on Neuromuscular Transmission in Frogs

1958 ◽  
Vol 193 (1) ◽  
pp. 213-218 ◽  
Author(s):  
Kyozo Koketsu
Keyword(s):  
Action Potential ◽  
Neuromuscular Transmission ◽  
Direct Action ◽  
Motor Nerve ◽  
Muscle Fibers ◽  
Nerve Fibers ◽  
Tetraethylammonium Chloride ◽  
Nerve Axon ◽  
Mechanical Responses ◽  
End Plate

The action of tetraethylammonium chloride (TEA-Cl) on the neuromuscular transmission in frogs of 0.2–3 mm concentration was analyzed by recording a) the mechanical responses; b) direct action on the muscle fibers; c) end-plate potential (e.p.p.); d) direct action on the end-plate membrane; e) sensitivity of end-plate membrane to the applied ACh; f) the action potential of terminal endings of motor nerve fibers; g) direct action of nerve axon. TEA-Cl in these concentrations augments the e.p.p., and this augmentation increases with increasing concentrations. A relatively higher concentration (1–3 mm) depresses the e.p.p. after an initial augmentation. The sensitivity of the end-plate membrane to ACh is depressed by 0.2–3 mm. TEA-Cl in these concentrations acts on the terminal endings of motor nerve fibers and prolongs the negative after-potential of terminal endings. It is suggested that TEA-Cl increases the release of ACh by acting on the terminal endings, thus causing the augmentation of e.p.p.'s. The action of TEA-Cl at a given concentration will be determined by separate actions both on the end-plate membrane and the terminal ending of motor nerve fibers.

scholarly journals Mechanism of changes of peripheral neuro-muscle endings of the tongues of rats with experimental streptozotocyn diabetes mellitus

2017 ◽  
Vol 8 (3) ◽  
pp. 397-402
Author(s):  
M. Luchynskyi ◽  
V. Luchinskyi ◽  
V. Shcherba ◽  
A. Demkovych ◽  
Y. Luchinska
Keyword(s):  
Diabetes Mellitus ◽  
Structural Changes ◽  
Morphological Changes ◽  
Muscle Fibers ◽  
Streptozotocin Diabetes ◽  
Nerve Fibers ◽  
Experimental Diabetes Mellitus ◽  
Two Stages ◽  
Reactive Processes ◽  
Muscular Tissues

The paper presents the characteric of dynamics of morphological changes of neuromuscular endings of the tongues of rats with experimentally induced streptozotocin diabetes mellitus. The hysto-ultrastructural research showed pathomorphologic changes in the experimental diabetes mellitus at different time periods. Their regulations indicate the relation of neuromuscular endings and elements of muscular tissues. During experimental streptozotocin diabetes mellitus, there occured interconnected structural changes of muscle fibers, myelin nerve fibers and the microcirculatory channel of the tongue with damage to the neuromuscular endings. In the dynamics of the diabetic process, three phases were distinguished: the phase of reactive-dystrophic changes with maximum severity two weeks after the beginning of the experimental modeling of streptozotocin diabetes mellitus; the phase of destructive-dystrophic processes, which began after the fourth week from the beginning of the modeling experimental streptozotocin diabetes; degenerative-destructive phase, which developed after the sixth week of the experiment. The dynamics of changes in the neuromuscular endings are also related to the duration of diabetes mellitus, they occur in two stages: in the first stage (up to 4 weeks) reactive processes were observed , in the second (6–8 weeks) – dystrophic processes. The uneven degree of their manifestation is related to the reaction of the microcirculatory channel of neuromuscular endings and composition of the tongue muscles. The greatest sensitivity to hyperglycemia was observed in muscle fibers of the intermediate type. 

Adaptive and Maladaptive Neural Plasticity Due to Facial Nerve Palsy

2016 ◽  
Vol 224 (2) ◽  
pp. 102-111 ◽  
Author(s):  
Carsten M. Klingner ◽  
Stefan Brodoehl ◽  
Gerd F. Volk ◽  
Orlando Guntinas-Lichius ◽  
Otto W. Witte
Keyword(s):  
Facial Nerve ◽  
Neural Plasticity ◽  
Cortical Plasticity ◽  
Brain Plasticity ◽  
Motor Nerve ◽  
Predictive Coding ◽  
Theoretical Framework ◽  
Cortical Reorganization ◽  
Nerve Lesion ◽  
Peripheral Facial Palsy

Abstract. This paper reviews adaptive and maladaptive mechanisms of cortical plasticity in patients suffering from peripheral facial palsy. As the peripheral facial nerve is a pure motor nerve, a facial nerve lesion is causing an exclusive deefferentation without deafferentation. We focus on the question of how the investigation of pure deefferentation adds to our current understanding of brain plasticity which derives from studies on learning and studies on brain lesions. The importance of efference and afference as drivers for cortical plasticity is discussed in addition to the crossmodal influence of different competitive sensory inputs. We make the attempt to integrate the experimental findings of the effects of pure deefferentation within the theoretical framework of cortical responses and predictive coding. We show that the available experimental data can be explained within this theoretical framework which also clarifies the necessity for maladaptive plasticity. Finally, we propose rehabilitation approaches for directing cortical reorganization in the appropriate direction and highlight some challenging questions that are yet unexplored in the field.

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