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1.
Ann Anat ; 227: 151429, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31634559

RESUMO

PURPOSE: To examine both the horizontal and vertical locations of the myoneural junction of the inferior oblique muscle (IOM) in reference to the ala nasi, IOM origin, and inferior orbital rim. MATERIALS AND METHODS: Fifty-six orbits from 56 Japanese cadavers (15 male and 41 female cadavers; average age at time of death, 86.5±9.4 years) were used in this experimental anatomical study. The inter-alae-nasi distance and the horizontal distances from the ipsilateral ala nasi to the IOM origin (ala-nasi-origin distance) and to the myoneural junction (ala-nasi-junction distance) were measured. The horizontal distance from the IOM origin to the myoneural junction (origin-junction distance) was calculated by subtraction of the ala-nasi-origin distance from the ala-nasi-junction distance. The vertical distance from the inferior orbital rim to the myoneural junction (rim-junction distance) was also measured. RESULTS: The ala-nasi-junction, origin-junction, and rim-junction distances were 12.2±3.2mm, 10.6±3.2mm, and 3.4±1.0mm, respectively. Males had a longer inter-alae-nasi distance than females (P<0.001), although the other distances did not show statistically significant sex-related difference (P>0.050). The ala-nasi-junction distance tended to be negatively correlated with the inter-alae-nasi distance (r=-0.222, P=0.050). CONCLUSIONS: The ala-nasi-junction distance can be affected by the inter-alae-nasi distance, which was found to be longer in males. Therefore, the IOM origin and the inferior orbital rim can be considered as more practical and reliable reference points to predict the location of the myoneural junction during the posterior inferior orbitotomy, irrespective of sex.


Assuntos
Junção Neuromuscular/anatomia & histologia , Músculos Oculomotores/anatomia & histologia , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Grupo com Ancestrais do Continente Asiático , Cadáver , Feminino , Humanos , Masculino , Músculos Oculomotores/inervação , Músculos Oculomotores/fisiologia , Órbita/anatomia & histologia , Fatores Sexuais
2.
J Comp Neurol ; 526(13): 1995-2009, 2018 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-29761896

RESUMO

Sphingolipids are found in abundance at synapses and have been implicated in regulation of synapse structure, function, and degeneration. Their precise role in these processes, however, remains obscure. Serine Palmitoyl-transferase (SPT) is the first enzymatic step for synthesis of sphingolipids. Analysis of the Drosophila larval neuromuscular junction (NMJ) revealed mutations in the SPT enzyme subunit, lace/SPTLC2 resulted in deficits in synaptic structure and function. Although NMJ length is normal in lace mutants, the number of boutons per NMJ is reduced to ∼50% of the wild type number. Synaptic boutons in lace mutants are much larger but show little perturbation to the general ultrastructure. Electrophysiological analysis of lace mutant synapses revealed strong synaptic transmission coupled with predominance of depression over facilitation. The structural and functional phenotypes of lace mirrored aspects of Basigin (Bsg), a small Ig-domain adhesion molecule also known to regulate synaptic structure and function. Mutant combinations of lace and Bsg generated large synaptic boutons, while lace mutants showed abnormal accumulation of Bsg at synapses, suggesting that Bsg requires sphingolipid to regulate structure of the synapse. In support of this, we found Bsg to be enriched in lipid rafts. Our data points to a role for sphingolipids in the regulation and fine-tuning of synaptic structure and function while sphingolipid regulation of synaptic structure may be mediated via the activity of Bsg.


Assuntos
Drosophila melanogaster/fisiologia , Junção Neuromuscular/anatomia & histologia , Junção Neuromuscular/fisiologia , Esfingolipídeos/fisiologia , Sinapses/fisiologia , Animais , Proteínas de Drosophila/genética , Proteínas de Drosophila/fisiologia , Fenômenos Eletrofisiológicos/fisiologia , Imuno-Histoquímica , Larva , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/fisiologia , Microdomínios da Membrana/fisiologia , Microdomínios da Membrana/ultraestrutura , Mutação/genética , Terminações Pré-Sinápticas/fisiologia , Terminações Pré-Sinápticas/ultraestrutura , Serina C-Palmitoiltransferase/genética , Serina C-Palmitoiltransferase/fisiologia
3.
Neurol Clin ; 36(2): 231-240, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29655446

RESUMO

Neuromuscular junctions (NMJs) form between nerve terminals of spinal cord motor neurons and skeletal muscles, and perisynaptic Schwann cells and kranocytes cap NMJs. One muscle fiber has one NMJ, which is innervated by one motor nerve terminal. NMJs are excitatory synapses that use P/Q-type voltage-gated calcium channels to release the neurotransmitter acetylcholine. Acetylcholine receptors accumulate at the postsynaptic specialization called the end plate on the muscle fiber membrane, the sarcolemma. Proteins essential for the organization of end plates include agrin secreted from nerve terminals, Lrp4 and MuSK receptors for agrin, and Dok-7 and rapsyn cytosolic proteins in the muscle.


Assuntos
Junção Neuromuscular/anatomia & histologia , Junção Neuromuscular/patologia , Animais , Humanos
4.
Cell Rep ; 21(9): 2348-2356, 2017 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-29186674

RESUMO

The neuromuscular junction (NMJ) plays a fundamental role in transferring information from lower motor neuron to skeletal muscle to generate movement. It is also an experimentally accessible model synapse routinely studied in animal models to explore fundamental aspects of synaptic form and function. Here, we combined morphological techniques, super-resolution imaging, and proteomic profiling to reveal the detailed cellular and molecular architecture of the human NMJ. Human NMJs were significantly smaller, less complex, and more fragmented than mouse NMJs. In contrast to mice, human NMJs were also remarkably stable across the entire adult lifespan, showing no signs of age-related degeneration or remodeling. Super-resolution imaging and proteomic profiling revealed distinctive distribution of active zone proteins and differential expression of core synaptic proteins and molecular pathways at the human NMJ. Taken together, these findings reveal human-specific cellular and molecular features of the NMJ that distinguish them from comparable synapses in other mammalian species.


Assuntos
Junção Neuromuscular/anatomia & histologia , Junção Neuromuscular/citologia , Envelhecimento/fisiologia , Animais , Humanos , Neurônios Motores/metabolismo , Músculo Esquelético/metabolismo , Sistema Nervoso/metabolismo , Junção Neuromuscular/metabolismo , Proteômica , Sinapses/metabolismo , Transmissão Sináptica/fisiologia
5.
J Neural Eng ; 14(3): 036011, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28358718

RESUMO

OBJECTIVE: To localize neuromuscular junctions in skeletal muscles in vivo which is of great importance in understanding, diagnosing and managing of neuromuscular disorders. APPROACH: A three-dimensional global innervation zone imaging technique was developed to characterize the global distribution of innervation zones, as an indication of the location and features of neuromuscular junctions, using electrically evoked high-density surface electromyogram recordings. MAIN RESULTS: The performance of the technique was evaluated in the biceps brachii of six intact human subjects. The geometric centers of the distributions of the reconstructed innervation zones were determined with a mean distance of 9.4 ± 1.4 cm from the reference plane, situated at the medial epicondyle of the humerus. A mean depth was calculated as 1.5 ± 0.3 cm from the geometric centers to the closed points over the skin. The results are consistent with those reported in previous histology studies. It was also found that the volumes and distributions of the reconstructed innervation zones changed as the stimulation intensities increased until the supramaximal muscle response was achieved. SIGNIFICANCE: Results have demonstrated the high performance of the proposed imaging technique in noninvasively imaging global distributions of the innervation zones in the three-dimensional muscle space in vivo, and the feasibility of its clinical applications, such as guiding botulinum toxin injections in spasticity management, or in early diagnosis of neurodegenerative progression of amyotrophic lateral sclerosis.


Assuntos
Algoritmos , Eletromiografia/métodos , Potencial Evocado Motor/fisiologia , Imageamento Tridimensional/métodos , Músculo Esquelético/inervação , Músculo Esquelético/fisiologia , Junção Neuromuscular/fisiopatologia , Adulto , Mapeamento Potencial de Superfície Corporal/métodos , Feminino , Humanos , Masculino , Junção Neuromuscular/anatomia & histologia , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
6.
Eur. j. anat ; 19(4): 351-359, oct. 2015. ilus, tab
Artigo em Inglês | IBECS | ID: ibc-145664

RESUMO

The movement of the fingers of the hand is thought to be limited in extension due in part to the presence of the juncturae tendinum (JT) in the dorsal webspaces. Clinically, these structures may help surgeons in identifying the extensor slips of the extensor digitorum communis (edc) and constitute an additional resource for tendon repair. These connections are highly variable in relation to their frequency and shape. Based on von Schroeder’s classification, an evidence synthesis of those structures was performed; nineteen cadaveric studies were located with a total of 2060 hands. Using meta-analytical methods, the pooled prevalence values were computed for each webspace and each type of JT; the JT type 1 (JT-1) and 3 (JT-3) were by far the most common in the 2nd and 4th webspaces, respectively. In the 3rd webspace, the JT type 2 (JT-2) had the highest prevalence value, followed by JT-3 and JT-1. The pooled means of JT size revealed that JT-3 was significantly longer and thicker than JT-1 and JT-2, while JT-1 was significantly wider than JT-2 and JT-3. Ancestry-based prevalence values showed that Middle Eastern populations had the lowest overall JT prevalence values, and Indian and Turkish ancestries had the highest values. Side-based prevalence values demonstrate significance only for the JT-3y type in the 4th webspace, where it was twice more frequent on the left side. While JT-3 was not infrequent between edc to the ring finger and extensor digiti minimi (16.5%), it occurred 13 times more when edc to the little finger was absent. This anatomical meta-analysis is likely to generate more accurate prevalence and mean size values of the juncturae tendinum in human hands


No disponible


Assuntos
Humanos , Tendões/anatomia & histologia , Mãos/anatomia & histologia , Junção Neuromuscular/anatomia & histologia , Anatomia Regional/métodos
7.
J Anat ; 227(2): 231-6, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26179026

RESUMO

I present here an overview of research on the biology of neuromuscular sensory and motor endings that was inspired and influenced partly by my educational experience in the Department of Zoology at the University of Durham, from 1971 to 1974. I allude briefly to neuromuscular synaptic structure and function in dystrophic mice, influences of activity on synapse elimination in development and regeneration, and activity-dependent protection and degeneration of neuromuscular junctions in Wld(S) mice.


Assuntos
Envelhecimento/fisiologia , Neurônios Motores/fisiologia , Degeneração Neural/fisiopatologia , Junção Neuromuscular , Células Receptoras Sensoriais/fisiologia , Animais , Axônios/fisiologia , Camundongos , Camundongos Transgênicos , Músculo Esquelético , Junção Neuromuscular/anatomia & histologia , Junção Neuromuscular/fisiologia
8.
Exp Neurol ; 270: 41-54, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25620417

RESUMO

Study of the electrophysiological function of the neuromuscular junction (NMJ) is instrumental in the understanding of the symptoms and pathophysiology of myasthenia gravis (MG), an autoimmune disorder characterized by fluctuating and fatigable muscle weakness. Most patients have autoantibodies to the acetylcholine receptor at the NMJ. However, in recent years autoantibodies to other crucial postsynaptic membrane proteins have been found in previously 'seronegative' MG patients. Electromyographical recording of compound and single-fibre muscle action potentials provides a crucial in vivo method to determine neuromuscular transmission failure while ex vivo (miniature) endplate potential recordings can reveal the precise synaptic impairment. Here we will review these electrophysiological methods used to assess NMJ function and discuss their application and typical results found in the diagnostic and experimental study of patients and animal models of the several forms of MG.


Assuntos
Miastenia Gravis/fisiopatologia , Junção Neuromuscular/anatomia & histologia , Junção Neuromuscular/fisiologia , Animais , Modelos Animais de Doenças , Eletrofisiologia , Humanos , Transmissão Sináptica/fisiologia
9.
Laryngoscope ; 125(2): 419-23, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25267429

RESUMO

OBJECTIVES/HYPOTHESIS: To better understand the reason for the low success rate of posterior cricoarytenoid (PCA) muscle reinnervation, we attempted to identify the communicating branches that may exist between the nerve branch to the PCA muscle and the other laryngeal adductors in addition to the interarytenoid (IA) muscle. STUDY DESIGN: Quantitative histological assessment. METHODS: Twenty human hemilarynges from patients with laryngeal or hypopharyngeal cancer were obtained after surgery and stained with Sihler's stain, which rendered the muscle translucent while counterstaining the neuroanatomy of the recurrent laryngeal nerve (RLN) inside the larynges. RESULTS: The nerve supply to the PCA muscle was separated into two main branches. One upper branch supplied the horizontal compartment, and the lower branch supplied the vertical/oblique compartment. In 14 specimens, two nerve branches to the PCA muscle arose separately from the RLN. In six specimens, one single main branch arose from the RLN and immediately ramified into two secondary branches. In all specimens except one, the nerve branch to the horizontal compartment was connected to the IA muscle. However, no communicating branches were observed between the nerve to the PCA muscle and the other laryngeal adductors. No anastomosis between nerve branches to the horizontal and vertical/oblique compartments or other variations of nerve distribution were observed. CONCLUSIONS: The communicating branches between the nerve branches to the PCA muscle and the IA muscle may be the only branch, complicating the reinnervation procedure. More investigations are needed to identify variations in the terminal branch distribution from the RLN. LEVEL OF EVIDENCE: NA.


Assuntos
Músculos Laríngeos/inervação , Músculos Laríngeos/cirurgia , Cartilagem Aritenoide/inervação , Cartilagem Cricoide/inervação , Feminino , Humanos , Técnicas In Vitro , Neoplasias Laríngeas/cirurgia , Masculino , Junção Neuromuscular/anatomia & histologia , Nervo Laríngeo Recorrente/anatomia & histologia , Coloração e Rotulagem
10.
Nat Commun ; 5: 3569, 2014 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-24686533

RESUMO

The neuromuscular junction (NMJ) exhibits high morphological and functional plasticity. In the mature muscle, the relative levels of physical activity are the major determinants of NMJ function. Classically, motor neuron-mediated activation patterns of skeletal muscle have been thought of as the major drivers of NMJ plasticity and the ensuing fibre-type determination in muscle. Here we use muscle-specific transgenic animals for the peroxisome proliferator-activated receptor γ co-activator 1α (PGC-1α) as a genetic model for trained mice to elucidate the contribution of skeletal muscle to activity-induced adaptation of the NMJ. We find that muscle-specific expression of PGC-1α promotes a remodelling of the NMJ, even in the absence of increased physical activity. Importantly, these plastic changes are not restricted to post-synaptic structures, but extended to modulation of presynaptic cell morphology and function. Therefore, our data indicate that skeletal muscle significantly contributes to the adaptation of the NMJ subsequent to physical activity.


Assuntos
Músculo Esquelético/metabolismo , Junção Neuromuscular/fisiologia , Fatores de Transcrição/metabolismo , Adaptação Fisiológica , Animais , Camundongos , Camundongos Transgênicos , Contração Muscular , Músculo Esquelético/anatomia & histologia , Junção Neuromuscular/anatomia & histologia , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo , Fatores de Transcrição/genética
11.
J Vis Exp ; (83): e51162, 2014 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-24457471

RESUMO

Analysis of neuromuscular junction morphology can give important insight into the physiological status of a given motor neuron. Analysis of thin flat muscles can offer significant advantage over traditionally used thicker muscles, such as those from the hind limb (e.g. gastrocnemius). Thin muscles allow for comprehensive overview of the entire innervation pattern for a given muscle, which in turn permits identification of selectively vulnerable pools of motor neurons. These muscles also allow analysis of parameters such as motor unit size, axonal branching, and terminal/nodal sprouting. A common obstacle in using such muscles is gaining the technical expertise to dissect them. In this video, we detail the protocol for dissecting the transversus abdominis (TVA) muscle from young mice and performing immunofluorescence to visualize axons and neuromuscular junctions (NMJs). We demonstrate that this technique gives a complete overview of the innervation pattern of the TVA muscle and can be used to investigate NMJ pathology in a mouse model of the childhood motor neuron disease, spinal muscular atrophy.


Assuntos
Músculos Abdominais/lesões , Músculos Abdominais/cirurgia , Junção Neuromuscular/anatomia & histologia , Animais , Dissecação/métodos , Imunofluorescência/métodos , Camundongos
12.
J Vis Exp ; (94)2014 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-25590231

RESUMO

The neuromuscular junction (NMJ) is the large, cholinergic relay synapse through which mammalian motor neurons control voluntary muscle contraction. Structural changes at the NMJ can result in neurotransmission failure, resulting in weakness, atrophy and even death of the muscle fiber. Many studies have investigated how genetic modifications or disease can alter the structure of the mouse NMJ. Unfortunately, it can be difficult to directly compare findings from these studies because they often employed different parameters and analytical methods. Three protocols are described here. The first uses maximum intensity projection confocal images to measure the area of acetylcholine receptor (AChR)-rich postsynaptic membrane domains at the endplate and the area of synaptic vesicle staining in the overlying presynaptic nerve terminal. The second protocol compares the relative intensities of immunostaining for synaptic proteins in the postsynaptic membrane. The third protocol uses Fluorescence Resonance Energy Transfer (FRET) to detect changes in the packing of postsynaptic AChRs at the endplate. The protocols have been developed and refined over a series of studies. Factors that influence the quality and consistency of results are discussed and normative data are provided for NMJs in healthy young adult mice.


Assuntos
Microscopia Confocal/métodos , Proteínas do Tecido Nervoso/metabolismo , Junção Neuromuscular/fisiologia , Sinapses/fisiologia , Animais , Feminino , Transferência Ressonante de Energia de Fluorescência , Camundongos , Camundongos Endogâmicos C57BL , Placa Motora/metabolismo , Junção Neuromuscular/anatomia & histologia , Junção Neuromuscular/metabolismo , Receptores Colinérgicos/metabolismo , Sinapses/metabolismo
13.
J Oral Maxillofac Surg ; 71(7): 1170-7, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23806734

RESUMO

PURPOSE: The temporalis muscle is commonly used for functional transfer. It is architecturally complex, but few studies have examined its intramuscular innervation and none has used 3-dimensional modeling techniques. Understanding neuromuscular compartmentalization may allow the design of local muscle transfers to minimize donor-site morbidity. The purpose of the present study was to document the intramuscular innervation patterns throughout the volume of the temporalis muscle and define functional units within the muscle. MATERIALS AND METHODS: In 10 formalin-embalmed cadaveric specimens, the foramen ovale was exposed and the branches of the mandibular nerve were identified. Each branch was digitized in short segments extramuscularly and intramuscularly. Three-dimensional models were reconstructed from the digitized data using Maya software, and the innervation patterns were documented. RESULTS: The temporalis muscle was found to have superior and inferior parts that were further grouped by innervation into regions, with each receiving its innervation from 1 primary nerve. The nerves originated directly from the mandibular nerve, except in 3 specimens, where the posterior deep temporal nerve arose from the masseteric nerve. CONCLUSION: These results provide a detailed mapping of innervation patterns and suggest there are at least 5 functional compartments. Each of these has the capacity for selective activation, 3 of which have clinical value. These findings may allow for decreased donor-site morbidity and more functionally sophisticated designs in clinical practice.


Assuntos
Imageamento Tridimensional/métodos , Músculo Temporal/inervação , Idoso , Idoso de 80 Anos ou mais , Cadáver , Dissecação , Fáscia/inervação , Humanos , Processamento de Imagem Assistida por Computador/métodos , Nervo Lingual/anatomia & histologia , Masculino , Nervo Mandibular/anatomia & histologia , Músculo Masseter/inervação , Pessoa de Meia-Idade , Junção Neuromuscular/anatomia & histologia , Retalhos Cirúrgicos/inervação , Adulto Jovem
14.
Methods Mol Biol ; 1018: 277-85, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23681637

RESUMO

Immunofluorescence or IF is a technique allowing the visualization of a specific protein or antigen in cells or tissues by binding a specific antibody chemically conjugated with a fluorescence dye. Immunofluorescent staining is widely used in life science research, particularly for neuroscience. Here, we describe the immunofluorescent staining of whole-mount neonatal mouse diaphragms to study the morphological patterns of the neuromuscular junction (NMJ) by using of presynaptic neuronal marker-neurofilament (NF) and synaptophysin antibodies; postsynaptic acetylcholine receptors (AChRs) were labeled with Alexa Fluor 594-conjugated α-bungarotoxin (α-BTX). Immunofluorescence-stained diaphragms were examined under a confocal microscope.


Assuntos
Diafragma/anatomia & histologia , Imunofluorescência/métodos , Junção Neuromuscular/anatomia & histologia , Coloração e Rotulagem , Animais , Animais Recém-Nascidos , Diafragma/citologia , Dissecação , Camundongos , Microscopia Confocal , Junção Neuromuscular/citologia , Fixação de Tecidos
15.
Eur J Neurosci ; 38(2): 2229-41, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23607735

RESUMO

Immunocytochemistry shows that purinergic receptors (P1Rs) type A1 and A2A (A1 R and A2 A R, respectively) are present in the nerve endings at the P6 and P30 Levator auris longus (LAL) mouse neuromuscular junctions (NMJs). As described elsewhere, 25 µm adenosine reduces (50%) acetylcholine release in high Mg(2+) or d-tubocurarine paralysed muscle. We hypothesize that in more preserved neurotransmission machinery conditions (blocking the voltage-dependent sodium channel of the muscle cells with µ-conotoxin GIIIB) the physiological role of the P1Rs in the NMJ must be better observed. We found that the presence of a non-selective P1R agonist (adenosine) or antagonist (8-SPT) or selective modulators of A1 R or A2 A R subtypes (CCPA and DPCPX, or CGS-21680 and SCH-58261, respectively) does not result in any changes in the evoked release. However, P1Rs seem to be involved in spontaneous release (miniature endplate potentials MEPPs) because MEPP frequency is increased by non-selective block but decreased by non-selective stimulation, with A1 Rs playing the main role. We assayed the role of P1Rs in presynaptic short-term plasticity during imposed synaptic activity (40 Hz for 2 min of supramaximal stimuli). Depression is reduced by micromolar adenosine but increased by blocking P1Rs with 8-SPT. Synaptic depression is not affected by the presence of selective A1 R and A2 A R modulators, which suggests that both receptors need to collaborate. Thus, A1 R and A2 A R might have no real effect on neuromuscular transmission in resting conditions. However, these receptors can conserve resources by limiting spontaneous quantal leak of acetylcholine and may protect synaptic function by reducing the magnitude of depression during repetitive activity.


Assuntos
Acetilcolina/metabolismo , Junção Neuromuscular/fisiologia , Receptor A1 de Adenosina/metabolismo , Receptor A2A de Adenosina/metabolismo , Transmissão Sináptica/fisiologia , Agonistas do Receptor A1 de Adenosina/farmacologia , Antagonistas do Receptor A1 de Adenosina/farmacologia , Agonistas do Receptor A2 de Adenosina/farmacologia , Antagonistas do Receptor A2 de Adenosina/farmacologia , Animais , Masculino , Camundongos , Junção Neuromuscular/anatomia & histologia , Junção Neuromuscular/metabolismo , Receptor A1 de Adenosina/efeitos dos fármacos , Receptor A2A de Adenosina/efeitos dos fármacos
16.
Surg Radiol Anat ; 35(10): 951-6, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23515955

RESUMO

PURPOSE: The aim of this study was to investigate the branches of the ulnar nerve given to forearm muscles [flexor carpi ulnaris (FCU) and flexor digitorum profundus (FDP)] and typing of ulnar nerve according to distribution of these branches to the muscles. METHODS: From the collection of Anatomy Department Laboratory, Faculty of Medicine, Suleyman Demirel University, 116 upper limbs of fetuses showing no external anomaly and aging between 12th and 40th weeks of pregnancy, were included in this study for anatomical dissection. Parameters about the branching of fetal ulnar nerve were set as follows: branch/branches to FCU muscle and branch/branches to FDP muscle. RESULTS: Ulnar nerve was typed according to number, sequence, and distribution of motor branches of ulnar nerve. As a result of this typing, eight type branching model of ulnar nerve was confirmed. CONCLUSIONS: Our study is critically important for implementing successful surgical interventions and minimizing complications especially in ulnar nerve and forearm muscles surgery also in nerve replacement on this area.


Assuntos
Antebraço/inervação , Músculo Esquelético/inervação , Junção Neuromuscular/anatomia & histologia , Nervo Ulnar/anatomia & histologia , Aborto Espontâneo , Cadáver , Dissecação , Feminino , Feto , Antebraço/anatomia & histologia , Idade Gestacional , Humanos , Músculo Esquelético/anatomia & histologia , Gravidez
17.
Trends Neurosci ; 35(7): 441-53, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22633140

RESUMO

The vertebrate neuromuscular junction (NMJ), a peripheral synapse formed between motoneuron and skeletal muscle, is characterized by a protracted postnatal period of maturation and life-long maintenance. In neuromuscular disorders such as congenital myasthenic syndromes (CMSs), disruptions of NMJ maturation and/or maintenance are frequently observed. In particular, defective neuromuscular transmission associated with structural and molecular abnormalities at the pre- and postsynaptic membranes, as well as at the synaptic cleft, has been reported in these patients. Here, we review recent advances in the understanding of molecular and cellular events that mediate NMJ maturation and maintenance. The underlying regulatory mechanisms, including key molecular regulators at the presynaptic nerve terminal, synaptic cleft, and postsynaptic muscle membrane, are discussed.


Assuntos
Junção Neuromuscular/anatomia & histologia , Junção Neuromuscular/fisiologia , Animais , Humanos
18.
Exp Neurol ; 236(1): 6-18, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22361024

RESUMO

We report a novel in vivo mouse model system to study regeneration of injured motor nerve and spatiotemporal pattern of denervation in experimental nerve diseases. The lateral thoracic nerve (LTN), as a pure motor nerve, innervates the cutaneous maximus muscle (CMM) by some of the shortest and the longest motor nerve fibers in the mouse body. Its branches and nerve terminals can be imaged in whole mount preparations. Here we describe the branching pattern of the LTN and its innervation of the CMM, and characterize degeneration and regeneration over time after a LTN crush by morphological and electrophysiological analyses. We demonstrate the utility of this model in a well-established neurotoxicity paradigm and in a genetic disease model of the peripheral neuropathy. Furthermore, this system enables punch biopsies that allow repeated and multi-location examinations for LTN regeneration and CMM reinnervation over time. The presence of the LTN and the CMM in a variety of species and its easy accessibility suggests that this in vivo model system offers considerable promise for future nerve degeneration and regeneration research.


Assuntos
Modelos Neurológicos , Músculo Esquelético/inervação , Regeneração Nervosa/fisiologia , Junção Neuromuscular/anatomia & histologia , Nervos Periféricos/anatomia & histologia , Degeneração Walleriana/fisiopatologia , Animais , Modelos Animais de Doenças , Camundongos , Camundongos Mutantes Neurológicos , Camundongos Transgênicos , Músculo Esquelético/fisiologia , Junção Neuromuscular/fisiologia , Nervos Periféricos/fisiologia , Degeneração Walleriana/patologia
19.
Proc Natl Acad Sci U S A ; 109(11): E648-55, 2012 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-22355119

RESUMO

Although the complexity and circuitry of nervous systems undergo evolutionary change, we lack understanding of the general principles and specific mechanisms through which it occurs. The Drosophila larval neuromuscular junction (NMJ), which has been widely used for studies of synaptic development and function, is also an excellent system for studies of synaptic evolution because the genus spans >40 Myr of evolution and the same identified synapse can be examined across the entire phylogeny. We have now characterized morphology of the NMJ on muscle 4 (NMJ4) in >20 species of Drosophila. Although there is little variation within a species, NMJ morphology and complexity vary extensively between species. We find no significant correlation between NMJ phenotypes and phylogeny for the species examined, suggesting that drift alone cannot explain the phenotypic variation and that selection likely plays an important role. However, the nature of the selective pressure is still unclear because basic parameters of synaptic function remain uniform. Whatever the mechanism, NMJ morphology is evolving rapidly in comparison with other morphological features because NMJ phenotypes differ even between several sibling species pairs. The discovery of this unexpectedly extensive divergence in NMJ morphology among Drosophila species provides unique opportunities to investigate mechanisms that regulate synaptic growth; the interrelationships between synaptic morphology, neural function, and behavior; and the evolution of nervous systems and behavior in natural populations.


Assuntos
Evolução Biológica , Drosophila/anatomia & histologia , Junção Neuromuscular/anatomia & histologia , Animais , Drosophila/genética , Deriva Genética , Larva/anatomia & histologia , Tamanho do Órgão , Fenótipo , Filogenia , Terminações Pré-Sinápticas , Especificidade da Espécie
20.
PLoS One ; 6(11): e27095, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22132088

RESUMO

Binocular vision requires intricate control of eye movement to align overlapping visual fields for fusion in the visual cortex, and each eye is controlled by 6 extraocular muscles (EOMs). Disorders of EOMs are an important cause of symptomatic vision loss. Importantly, EOMs represent specialized skeletal muscles with distinct gene expression profile and susceptibility to neuromuscular disorders. We aim to investigate and describe the anatomy of adult zebrafish extraocular muscles (EOMs) to enable comparison with human EOM anatomy and facilitate the use of zebrafish as a model for EOM research. Using differential interference contrast (DIC), epifluorescence microscopy, and precise sectioning techniques, we evaluate the anatomy of zebrafish EOM origin, muscle course, and insertion on the eye. Immunofluorescence is used to identify components of tendons, basement membrane and neuromuscular junctions (NMJs), and to analyze myofiber characteristics. We find that adult zebrafish EOM insertions on the globe parallel the organization of human EOMs, including the close proximity of specific EOM insertions to one another. However, analysis of EOM origins reveals important differences between human and zebrafish, such as the common rostral origin of both oblique muscles and the caudal origin of the lateral rectus muscles. Thrombospondin 4 marks the EOM tendons in regions that are highly innervated, and laminin marks the basement membrane, enabling evaluation of myofiber size and distribution. The NMJs appear to include both en plaque and en grappe synapses, while NMJ density is much higher in EOMs than in somatic muscles. In conclusion, zebrafish and human EOM anatomy are generally homologous, supporting the use of zebrafish for studying EOM biology. However, anatomic differences exist, revealing divergent evolutionary pressures.


Assuntos
Envelhecimento/fisiologia , Olho/anatomia & histologia , Músculos/anatomia & histologia , Peixe-Zebra/anatomia & histologia , Animais , Animais Geneticamente Modificados , Bungarotoxinas/metabolismo , Embrião não Mamífero/anatomia & histologia , Imunofluorescência , Proteínas de Fluorescência Verde/metabolismo , Humanos , Laminina/metabolismo , Microscopia de Fluorescência , Junção Neuromuscular/anatomia & histologia , Órbita/anatomia & histologia , Trombospondinas/metabolismo
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