STRUCTURE AND FUNCTION OF NEUROMUSCULAR JUNCTIONS IN THE VASTUS LATERALIS OF MAN

Brain ◽  
1992 ◽  
Vol 115 (2) ◽  
pp. 451-478 ◽  
Author(s):  
E. BOLLEN ◽  
J. C. DEN HEYER ◽  
M. H. J. TOLSMA ◽  
S. BELLAR ◽  
J. E. BOS ◽  
...  
Keyword(s):  
Neuromuscular Junctions ◽  
Vastus Lateralis ◽  
Structure And Function ◽  
And Function

scholarly journals Effect of increased serum 25(OH)D and calcium on structure and function of post-menopausal women: a pilot study

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
H. J. Hillstrom ◽  
R. Soeters ◽  
M. Miranda ◽  
S. I. Backus ◽  
J. Hafer ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fatigue ◽  
Repeated Measures ◽  
Vastus Lateralis ◽  
Structure And Function ◽  
Muscle Size ◽  
Menopausal Women ◽  
Post Menopausal ◽  
And Function

Abstract Summary The purpose was to determine if increasing serum 25(OH)D and calcium in postmenopausal women increased skeletal muscle size, strength, balance, and functional task performance while decreasing muscle fatigue. PCSA of the vastus lateralis increased and ascent of stairs time decreased after 6 months of increased serum 25(OH)D. Purpose The Institute of Medicine recommends ≥ 20 ng/ml of serum 25-hydroxyvitamin D [25(OH)D] for bone and overall health. Serum 25(OH)D levels have been associated with physical performance, postural sway, and falls. The purpose of this study was to determine if increasing postmenopausal women’s serum 25(OH)D levels from 20–30 ng/ml to 40–50 ng/ml improved skeletal muscle size, strength, balance, and functional performance while decreasing skeletal muscle fatigue. Methods Twenty-six post-menopausal women (60–85 years old) with baseline serum 25(OH)D levels between 20 and 30 ng/ml were recruited. Oral over-the-counter (OTC) vitamin D3 and calcium citrate were prescribed to increase subjects’ serum 25(OH)D to levels between 40 and 50 ng/ml, serum calcium levels above 9.2 mg/dl, and PTH levels below 60 pg/ml, which were confirmed at 6 and 12 weeks. Outcome measures assessed at baseline and 6 months included muscle physiological cross-sectional area (PCSA), muscle strength, postural balance, time to perform functional tasks, and muscle fatigue. Repeated measures comparisons between baseline and follow-up were performed. Results Nineteen subjects completed the study. One individual could not afford the time commitment for the repeated measures. Three individuals did not take their vitamin D as recommended. Two subjects were lost to follow-up (lack of interest), and one did not achieve targeted serum 25(OH)D. Vastus lateralis PCSA increased (p = 0.007) and ascent of stair time decreased (p = 0.042) after 6 months of increasing serum 25(OH)D levels from 20–30 ng/ml to 40–50 ng/ml. Isometric strength was unchanged. Anterior-posterior center of pressure (COP) excursion and COP path length decreased (p < 0.1) albeit non-significantly, suggesting balance may improve from increased serum 25(OH)D and calcium citrate levels. Conclusions Several measures of muscle structure and function were sensitive to elevated serum 25(OH)D and calcium levels indicating that further investigation of this phenomenon in post-menopausal women is warranted.

Dynamics of nerve-muscle interaction in developing and mature neuromuscular junctions

1995 ◽  
Vol 75 (4) ◽  
pp. 789-834 ◽  
Author(s):  
A. D. Grinnell
Keyword(s):  
Synapse Formation ◽  
Neuromuscular Junctions ◽  
Structure And Function ◽  
Axon Pathfinding ◽  
Control Of Gene Expression ◽  
Synaptic Structure ◽  
Dynamic Cell ◽  
Nerve Muscle ◽  
And Function ◽  
Motoneuron Cell

Neuromuscular connections have long served as models of synaptic structure and function. They also provide illuminating insights into the dynamic cell-cell interactions governing synaptogenesis, neuromuscular differentiation, and the maintenance of effective function. This paper reviews recent advances in our understanding of the regulatory and inductive interactions involved in motor axon pathfinding, target recognition, bidirectional control of gene expression during synapse formation, motoneuron cell death, terminal rearrangement, and the ongoing remodeling of synaptic number, structure, and function to adjust to growth and changes in use.

scholarly journals Fast widefield imaging of neuronal structure and function with optical sectioning in vivo

2020 ◽  
Vol 6 (19) ◽  
pp. eaaz3870 ◽  
Author(s):  
Ziwei Li ◽  
Qinrong Zhang ◽  
Shih-Wei Chou ◽  
Zachary Newman ◽  
Raphaël Turcotte ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
In Vivo Imaging ◽  
Neuromuscular Junctions ◽  
Structure And Function ◽  
Structured Illumination ◽  
Neuronal Structure ◽  
Optical Sectioning ◽  
Structured Illumination Microscopy ◽  
And Function

Optical microscopy, owing to its noninvasiveness and subcellular resolution, enables in vivo visualization of neuronal structure and function in the physiological context. Optical-sectioning structured illumination microscopy (OS-SIM) is a widefield fluorescence imaging technique that uses structured illumination patterns to encode in-focus structures and optically sections 3D samples. However, its application to in vivo imaging has been limited. In this study, we optimized OS-SIM for in vivo neural imaging. We modified OS-SIM reconstruction algorithms to improve signal-to-noise ratio and correct motion-induced artifacts in live samples. Incorporating an adaptive optics (AO) module to OS-SIM, we found that correcting sample-induced optical aberrations was essential for achieving accurate structural and functional characterizations in vivo. With AO OS-SIM, we demonstrated fast, high-resolution in vivo imaging with optical sectioning for structural imaging of mouse cortical neurons and zebrafish larval motor neurons, and functional imaging of quantal synaptic transmission at Drosophila larval neuromuscular junctions.

scholarly journals Lynx1 regulates nAChRs to preserve the structure and function of neuromuscular synapses during aging

2020 ◽  
Author(s):  
Sydney V. Doss ◽  
Sébastien Barbat-Artigas ◽  
Tracey Myers ◽  
Bhola Shankar Pradhan ◽  
Tomasz J. Prószyński ◽  
...  
Keyword(s):  
Nicotinic Acetylcholine Receptors ◽  
Acetylcholine Receptors ◽  
Neuromuscular Junctions ◽  
Structure And Function ◽  
Neuromuscular Synapses ◽  
Adult Mice ◽  
Homeostatic Synaptic Plasticity ◽  
Age Related ◽  
And Function ◽  
The Brain

AbstractNicotinic acetylcholine receptors (nAChRs) undergo aberrant changes in diseases and with advancing age that compromise the structure and function of neuromuscular junctions (NMJs). Despite this recognition, the mechanisms that regulate muscle nAChRs remain poorly understood. Here, we ask if Lynx1, shown to regulate nAChRs in the brain, plays a similar role at NMJs. We show that Lynx1 concentrates in the postsynaptic region of NMJs where it modulates the function and stability of nAChRs in young adult mice. However, Lynx1 levels decrease at aged NMJs suggesting roles in synaptic maintenance. Supporting this possibility, deletion of Lynx1 prematurely and progressively increases the incidence of NMJs with age-related features, culminating in the atrophy of muscle fibers. These data show that by promoting homeostatic synaptic plasticity and NMJ remodeling, Lynx1 regulation of nAChRs mitigates age-related damages at NMJs.

Changes in structure and function of diaphragm neuromuscular junctions from BACHD mouse model for Huntington's disease

2016 ◽  
Vol 93 ◽  
pp. 64-72 ◽  
Author(s):  
Bárbara Campos de Aragão ◽  
Hermann Alecsandro Rodrigues ◽  
Priscila Aparecida Costa Valadão ◽  
Wallace Camargo ◽  
Lígia Araujo Naves ◽  
...  
Keyword(s):  
Mouse Model ◽  
Huntington's Disease ◽  
Huntington’S Disease ◽  
Neuromuscular Junctions ◽  
Structure And Function ◽  
And Function

scholarly journals The structure and function of ‘active zone material’ at synapses

2015 ◽  
Vol 370 (1672) ◽  
pp. 20140189 ◽  
Author(s):  
Joseph A. Szule ◽  
Jae Hoon Jung ◽  
Uel J. McMahan
Keyword(s):  
Spatial Resolution ◽  
Active Zone ◽  
Synaptic Vesicles ◽  
Neuromuscular Junctions ◽  
Electron Tomography ◽  
Structure And Function ◽  
Presynaptic Membrane ◽  
Axon Terminals ◽  
Active Zones ◽  
And Function

The docking of synaptic vesicles on the presynaptic membrane and their priming for fusion with it to mediate synaptic transmission of nerve impulses typically occur at structurally specialized regions on the membrane called active zones. Stable components of active zones include aggregates of macromolecules, ‘active zone material’ (AZM), attached to the presynaptic membrane, and aggregates of Ca 2+ -channels in the membrane, through which Ca 2+ enters the cytosol to trigger impulse-evoked vesicle fusion with the presynaptic membrane by interacting with Ca 2+ -sensors on the vesicles. This laboratory has used electron tomography to study, at macromolecular spatial resolution, the structure and function of AZM at the simply arranged active zones of axon terminals at frog neuromuscular junctions. The results support the conclusion that AZM directs the docking and priming of synaptic vesicles and essential positioning of Ca 2+ -channels relative to the vesicles' Ca 2+ -sensors. Here we review the findings and comment on their applicability to understanding mechanisms of docking, priming and Ca 2+ -triggering at other synapses, where the arrangement of active zone components differs.

Structure and function of neural networks in the retina

1988 ◽  
Vol 46 ◽  
pp. 26-27
Author(s):  
Peter Sterling
Keyword(s):  
Ganglion Cells ◽  
Three Dimensional ◽  
Structure And Function ◽  
Synaptic Connections ◽  
Visual Axis ◽  
One Dimensional ◽  
Cat Retina ◽  
Ultrathin Sections ◽  
And Function ◽  
Insight Into

The synaptic connections in cat retina that link photoreceptors to ganglion cells have been analyzed quantitatively. Our approach has been to prepare serial, ultrathin sections and photograph en montage at low magnification (˜2000X) in the electron microscope. Six series, 100-300 sections long, have been prepared over the last decade. They derive from different cats but always from the same region of retina, about one degree from the center of the visual axis. The material has been analyzed by reconstructing adjacent neurons in each array and then identifying systematically the synaptic connections between arrays. Most reconstructions were done manually by tracing the outlines of processes in successive sections onto acetate sheets aligned on a cartoonist's jig. The tracings were then digitized, stacked by computer, and printed with the hidden lines removed. The results have provided rather than the usual one-dimensional account of pathways, a three-dimensional account of circuits. From this has emerged insight into the functional architecture.

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