scholarly journals Locations of the Motor Endplate Band and Motoneurons Innervating the Sternomastoid Muscle in the Rat

2010 ◽  
Vol 294 (2) ◽  
pp. 295-304 ◽  
Author(s):  
Xiaolin Zhang ◽  
Liancai Mu ◽  
Hungxi Su ◽  
Stanislaw Sobotka
Keyword(s):  
Motor Endplate ◽  
Sternomastoid Muscle

Human motor endplate remodeling after traumatic nerve injury

2020 ◽  
pp. 1-8
Author(s):  
Ranjan Gupta ◽  
Justin P. Chan ◽  
Jennifer Uong ◽  
Winnie A. Palispis ◽  
David J. Wright ◽  
...  
Keyword(s):  
Peripheral Nerve ◽  
Nerve Injury ◽  
Surgical Intervention ◽  
Linear Regression Analysis ◽  
Motor Endplate ◽  
Nerve Injuries ◽  
Denervated Muscle ◽  
Sequence Of Events ◽  
Human Motor ◽  
Denervated Muscles

OBJECTIVECurrent management of traumatic peripheral nerve injuries is variable with operative decisions based on assumptions that irreversible degeneration of the human motor endplate (MEP) follows prolonged denervation and precludes reinnervation. However, the mechanism and time course of MEP changes after human peripheral nerve injury have not been investigated. Consequently, there are no objective measures by which to determine the probability of spontaneous recovery and the optimal timing of surgical intervention. To improve guidance for such decisions, the aim of this study was to characterize morphological changes at the human MEP following traumatic nerve injury.METHODSA prospective cohort (here analyzed retrospectively) of 18 patients with traumatic brachial plexus and axillary nerve injuries underwent biopsy of denervated muscles from the upper extremity from 3 days to 6 years after injury. Muscle specimens were processed for H & E staining and immunohistochemistry, with visualization via confocal and two-photon excitation microscopy.RESULTSImmunohistochemical analysis demonstrated varying degrees of fragmentation and acetylcholine receptor dispersion in denervated muscles. Comparison of denervated muscles at different times postinjury revealed progressively increasing degeneration. Linear regression analysis of 3D reconstructions revealed significant linear decreases in MEP volume (R = −0.92, R2 = 0.85, p = 0.001) and surface area (R = −0.75, R2 = 0.56, p = 0.032) as deltoid muscle denervation time increased. Surprisingly, innervated and structurally intact MEPs persisted in denervated muscle specimens from multiple patients 6 or more months after nerve injury, including 2 patients who had presented > 3 years after nerve injury.CONCLUSIONSThis study details novel and critically important data about the morphology and temporal sequence of events involved in human MEP degradation after traumatic nerve injuries. Surprisingly, human MEPs not only persisted, but also retained their structures beyond the assumed 6-month window for therapeutic surgical intervention based on previous clinical studies. Preoperative muscle biopsy in patients being considered for nerve transfer may be a useful prognostic tool to determine MEP viability in denervated muscle, with surviving MEPs also being targets for adjuvant therapy.

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 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

The Motor Endplate.

1964 ◽  
Vol 11 (6) ◽  
pp. 684-685
Author(s):  
W. L. Nastuk
Keyword(s):  
Motor Endplate

scholarly journals Distribution of extrajunctional acetylcholine receptors on a vertebrate muscle: evaluated by using a scanning electron microscope autoradiographic procedure.

1988 ◽  
Vol 106 (6) ◽  
pp. 2087-2093 ◽  
Author(s):  
M M Salpeter ◽  
M Marchaterre ◽  
R Harris
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Acetylcholine Receptors ◽  
Receptor Site ◽  
Spatial Density ◽  
Sternomastoid Muscle ◽  
Site Density ◽  
Vertebrate Muscle ◽  
Autoradiographic Technique ◽  
Scanning Electron

A scanning electron microscope (SEM) autoradiographic technique was calibrated and used to determine the site density of acetylcholine receptors within 250 micron of the neuromuscular junction in innervated as well as 3- and 10-d denervated sternomastoid muscle of the mouse. In all these groups sharp gradients of receptor site density are seen around the endplates in the first 2-7 micron, continuing less sharply to between 25 and 50 micron. Beyond 50 micron (to 250 micron) a spatial density gradient is present 3 d after denervation, but none exist by 10 d. These results suggest that the postdenervation steady-state extrajunctional receptor site density is reached sooner near the junction than away from the junction. The usefulness of SEM autoradiography to study the expression and distribution of membrane molecules at high resolution is demonstrated.

The Dual Role of Calcium in Synaptic Plasticity at the Motor Endplate

1997 ◽  
pp. 7-12 ◽  
Author(s):  
Samuel R. H. Joseph ◽  
Volker Steuber ◽  
David J. Willshaw
Keyword(s):  
Synaptic Plasticity ◽  
Dual Role ◽  
Motor Endplate
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