Dissertations / Theses on the topic 'Spinal motoneuron'
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Narayan, Sreenath. "REANIMATION OF A DENERVATED MUSCLE USING UPPER MOTONEURON INJURED LOWER MOTONEURONS IN SPINAL CORD INJURY PATIENTS: A RAT MODEL." online version, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=case1133754830.
Full textChopek, Jeremy W. "Lumbar spinal cord excitability: flexors vs. extensors, sensitivity to quipazine; effects of activity following spinal transection; and expression of post-synaptic serotonin receptors." American Physiological Society, 2013. http://hdl.handle.net/1993/24099.
Full textArumugam, Saravanan. "A Study on the Role of NF-kB Signaling Pathway Members in Regulating Survival Motor Neuron Protein level and in the Pathogenesis of Spinal Muscular Atrophy." Doctoral thesis, Universitat de Lleida, 2017. http://hdl.handle.net/10803/400607.
Full textLa Atrofia Muscular Espinal (SMA) es un trastorno neuromuscular causado por la mutación o deleción del gen SMN1, el cual codifica para la proteína que se expresa ubicuamente SMN (del inglés Survival Motor Neuron). La AME se caracteriza por atrofia muscular y degeneración de las motoneuronas de la médula espinal (MN). Los eventos moleculares detrás de la vulnerabilidad selectiva de las MN con niveles bajos de la proteína SMN se desconocen. La vía del factor nuclear-kB (NF-kB) ha sido implicada recientemente en la supervivencia de las MNs, así como en trastornos neurodegenerativos. Los factores de transcripción NF-kB regulan genes relacionados con varios procesos celulares. En este trabajo hemos analizado la capacidad de los miembros de la vía del NF-κB de regular la proteína SMN y su posible rol en la patogénesis del AME. La activación de la vía del NF-κB está asociada a la fosforilación de IKKα / IKKβ y la translocación nuclear del factor RelA/ p50 (vía canónica) o la fosforilación del homodímero de IKKα y la translocación nuclear del factor RelB / p52 (vía no canónica). Hemos realizado la inhibición de diferentes miembros de estas vías (tanto la canónica como la no canónica) usando la metodología de shRNA, y la transducción mediante el uso de lentivirus, en cultivos primarios de MN embrionarias aisladas de ratón. Hemos demostrado que una reducción selectiva del factor RelA provoca una reducción de la proteína SMN, mientras que una reducción del factor RelB no tiene ningún efecto en los niveles de la SMN. En nuestro modelo celular, la reducción de las proteínas IKKα o IKKβ mostró efectos opuestos sobre la proteína Smn. Mediante la técnica de PCR, hemos observado que la transducción de las MN con el shIKKβ provoca un aumento de los niveles de mRNA de SMN, mientras que la transducción con el shIKKα o el shRelA no cambian los niveles de RNA de SMN. El doble knockdown de IKKα e IKKβ en las MN muestra una reducción de SMN. El knockdown selectivo de IKKα o IKKβ presenta una reducción de la fosforilación del RelA, esta fosforilación permite la liberación de su inhibidor en el citosol y facilita la translocación nuclear. La proteína CREB, uno de los factores de transcripción conocidos para SMN, disminuye con la transducción de las MN con shIKKα o con IKKα e IKKβ a la vez, así como con shRelA. Ahora bien, las motoneuronas transducidas con shIKKβ muestran una reducción de la fosforilación de RelA pero un aumento de los niveles de la proteína CREB. La transducción de las MN con el shCREB disminuyó los niveles de la proteína SMN apoyando el papel regulador de CREB sobre SMN.
Spinal Muscular Atrophy (SMA) is a neuromuscular disorder caused by mutation or loss in SMN1 gene, encoding the ubiquitously expressed Survival Motor Neuron (SMN) protein. SMA is characterized by muscle atrophy, and spinal cord motoneurons (MNs) degeneration. The molecular events behind the selective vulnerability of these MNs to low level of SMN protein are still unknown. The nuclear factor-κB (NF-κB) pathway has recently been emerged having a vital role related to MN survival, and in neurodegenerative disorders. The NF-κB transcription factors regulate genes related to several cellular processes. In the present work, we have analyzed the ability of NF-κB pathway members to regulate Smn and their possible role in SMA pathogenesis. The NF-κB pathway activation is associated with IKKα/IKKβ phosphorylation, and RelA/p50 nuclear translocation (canonical) or IKKα homodimer phosphorylation, and RelB/p52 nuclear translocation (non-canonical). The inhibition of different protein members of both canonical, and non-canonical pathways using shRNA lentiviral transduction methodology in a primary culture of isolated embryonic spinal cord MNs reveals that the selective reduction of RelA induced the reduction of Smn whereas RelB protein reduction had no effect on Smn. In our culture system, reduction of IKKα or IKKβ proteins showed opposite effects on Smn. RT-PCR studies indicate that the shIKKβ-transduced MNs showed increased Smn mRNA levels, whereas it was not observed changes in Smn mRNA in the case of shIKKα- or shRelA-transduced MNs. The double knock-down of IKKα and IKKβ in MNs showed Smn reduction. The knockdown of IKKα and/or IKKβ showed a decrease in RelA phosphorylation, where the phosphorylation of RelA enable RelA/p50 release from its inhibitor in the cytoplasm and facilitates their nuclear translocation. Also, the CREB, one of the transcription factors for Smn was decreased in shIKKα, or in shIKKα- plus IKKβ-transduced MNs, and as well as in shRelA-transduced MNs. But, the shIKKβ MNs exhibited reduced p-RelA but increased CREB level. The shCREB-transduced MNs decreased Smn level, authenticating the regulatory role of CREB on Smn. We observed a reduction in IKKα, IKKβ and p-RelA levels in shSmn-tranduced MNs, and in MNs from a severe type SMA mouse model. Our results show the ability of NF-κB canonical pathway to regulate Smn level and, conversely, this pathway is also altered in Smn-deficient MNs. Together, these observations suggest that the NF-κB pathway has a role in SMA pathogenesis, and could be a therapeutic target for SMA.
Sowd, Matthew Michael. "Analyzing Non-Unique Parameters in a Cat Spinal Cord Motoneuron Model." Thesis, Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/11545.
Full textRademacher, Sebastian [Verfasser]. "Cytoskeletal dysregulation in the motoneuron disease Spinal Muscular Atrophy (SMA) / Sebastian Rademacher." Hannover : Bibliothek der Tierärztlichen Hochschule Hannover, 2017. http://d-nb.info/1136298002/34.
Full textZelano, Johan. "Adhesion molecules and synapse remodeling during motoneuron regeneration." Stockholm : Department of Neuroscience, Karolinska Institutet, 2009. http://diss.kib.ki.se/2009/978-91-7409-623-1/.
Full textVan, Ryswyk Liesl, and Ryswyk Liesl Van. "A Question of Identity: Genes that Distinguish Motoneurons from Interneurons." Thesis, University of Oregon, 2012. http://hdl.handle.net/1794/12539.
Full text柴宏 and Hong Chai. "Survival and regeneration of spinal motoneuron after ventral root avulsion in adult rat." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B3124158X.
Full textChai, Hong. "Survival and regeneration of spinal motoneuron after ventral root avulsion in adult rat /." Hong Kong : University of Hong Kong, 2000. http://sunzi.lib.hku.hk/hkuto/record.jsp?
Full textObeidat, Ahmed Zayed. "New Insights into the Spinal Recurrent Inhibitory Pathway Normally and After Motoneuron Regeneration." Wright State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=wright1369702090.
Full textYuan, Chun-Su. "ELECTROPHYSIOLOGICAL ANALYSIS OF THE RECURRENT RENSHAW CIRCUIT (MOTONEURON, INHIBITION, SPIKE-TRIGGERED AVERAGE, SPINAL CORD)." Diss., The University of Arizona, 1986. http://hdl.handle.net/10150/188170.
Full textMoore, N. J. "Recurrent excitation and inhibition in the Renshaw cell-motoneuron circuit of the lumbar spinal cord." Thesis, University College London (University of London), 2015. http://discovery.ucl.ac.uk/1458605/.
Full textMcWhorter, Michelle L. "Development and analysis of a Zebrafish model of spinal muscular atrophy." Columbus, Ohio : Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1133212697.
Full textPeriyakaruppiah, Ambika. "Study of Survival Motor Neuron protein regulation and the role of autophagy in Spinal Muscular Atrophy." Doctoral thesis, Universitat de Lleida, 2015. http://hdl.handle.net/10803/296677.
Full textL'atròfia muscular espinal (SMA) és un trastorn genètic, causada per la pèrdua o la mutació del gen de la supervivencia de les neurones motores 1 (SMN1), cosa que condueix a una reducció dels nivells de la proteïna SMN i una disfunció selectiva de les MN. S’ha descrit que la reducció d’SMN causa la degeneració de les neurites i la mort cel•lular sense les característiques apoptòtiques clàssiques, però els esdeveniments directes que condueixen a la degeneració de les MN en l’SMA encara són desconeguts. L’autofàgia és una diana principal per al tractament de moltes malalties neurodegeneratives. L'objectiu d’aquest estudi és analitzar el paper de l'autofàgia en la patologia de l’SMA, els mecanismes que regulen la degradació de la proteïna SMN i l'origen de la neurodegeneració en les MN de la medul•la espinal. Amb aquesta finalitat, hem reduït la proteïna SMN utilitzant el mètode de silenciament amb lentivirus. Hem analitzat els canvis en els marcadors d’autofàgia en les MN en cultiu amb l’SMN reduïda amb lentivirus i en cultius de MN de models de ratolins transgènics de SMA de tipus I. Hem observat que la reducció de l’SMN provoca un augment dels marcadors d’autofàgia i l'acumulació d’autofagosomes. A més, el tractament amb activadors de l'autofàgia, inhibidors de l'autofàgia o inhibidors del proteasoma o calpaïna indueix canvis en els nivells de la proteïna SMN en les MN, la qual cosa suggereix un paper de l'autofàgia i el proteasoma en la regulació de la proteïna SMN en aquestes cèl•lules. Conjuntament, aquests resultats contribueixen a una nova visió sobre la regulació de la proteïna SMN en les MN i sobre el possible paper de l'autofàgia en la neurodegeneració en l’ SMA.
La atrofia muscular espinal (AME) es un trastorno genético causado por la pérdida de la supervivencia de las neuronas motoras del gen 1 (SMN1) que conduce a la reducción de nivel de proteína SMN y a la disfunción selectiva de los MNs. La reducción de SMN causa la degeneración de axones y la muerte celular sin características apoptóticas clásicas; sin embargo, los motivos directos que conducen a la degeneración del MN en AME aún se desconocen. La autofagia está siendo un objetivo principal para el tratamiento de muchas enfermedades neurodegenerativas. El objetivo del presente estudio es analizar el papel de la autofagia en la patología de la AME, los mecanismos que regulan la degradación de la proteína SMN y el origen de la neurodegeneración de los MNs en la médula espinal. Con este fin, hemos reducido la proteína SMN utilizando un método de reducción lentiviral. En la Smn reducida mediante el método de reducción lentiviral y modelos de ratones transgénicos AME de tipo I, hemos observado el aumento de los marcadores de autofagia y la acumulación de autofagosoma. El tratamiento con activadores o inhibidores de la autofagia o inhibidores del proteasoma o calpaína reducida induce cambios del nivel de la proteína SMN en los MNs que demuestran el papel de la autofagia y del proteasoma en la regulación de la proteína SMN en estas células. Por lo tanto, los resultados contribuyen a una nueva visión sobre la regulación de las proteínas Smn en el MN y el posible papel de la autofagia en la neurodegeneración de AME.
Richards, Dannette Shanon. "CHARACTERIZATION OF EXCITATORY AMINO ACID NEUROTRANSMITTERS AT MOTONEURON SYNAPSES CONTACTING RENSHAW CELLS." Wright State University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=wright1260896604.
Full textRomer, Shannon Hunt. "The Organization of Kv2.1 ChannelProteins in the Membrane of Spinal Motoneurons:Regulation by Injury and Cellular Activity." Wright State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=wright1425136084.
Full textHensel, Niko [Verfasser]. "Analysis and inhibition of dysregulated pathways in a mouse model of the motoneuron disease Spinal Muscular Atrophy / Niko Hensel." Hannover : Bibliothek der Tierärztlichen Hochschule Hannover, 2014. http://d-nb.info/105431201X/34.
Full textKastanenka, Ksenia V. "IN VIVO ACTIVATION OF CHANNELRHODOPSIN-2 USED TO DETERMINE THE ROLE OF SPONTANEOUS NEURAL ACTIVITY IN AXONAL GUIDANCE." Case Western Reserve University School of Graduate Studies / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=case1307741269.
Full textGuzulaitis, Robertas. "The organisation principles of spinal neural network: temporal integration of somatosensory input and distribution of network activity." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2013. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2013~D_20130925_093153-76748.
Full textNugaros smegenys gauna somatosensorinę informaciją, ją integruoja ir generuoja motorinius atsakus. Disertacijoje parodoma, kad somatosensorinių įėjimų viršsekundinė laikinė integracija nugaros smegenų neuronų tinkle vyksta ne dėl motorinių neuronų vidinių savybių kitimo. Laikinės integracijos metu padidėja priešmotorinių neuronų aktyvumas ir tai gali lemti informacijos apie somatosensorinį įėjimą saugojimą. Somatosensorinis tylos periodas – tai motorinio aktyvumo slopinimas po skausmingo stimulo. Jis plačiai aprašytas žmonėse, bei taikomas diagnostikoje. Nepaisant plataus taikymo, somatosensorinio tylos periodo mechanizmai nėra ištirti – nebuvo žinoma ar šis motorinio aktyvumo slopinimas vyksta slopinant motorinius neuronus, ar eliminuojant motorinių neuronų žadinimą. Disertacijoje parodoma, kad somatosensorinio tylos periodo metu motoriniai neuronai yra slopinami. Be somatosensorinės informacijos apdorojimo nugaros smegenų neuronų tinklai užtikrina judėjimo ir refleksų valdymą. Yra priimta, kad priekines ir užpakalines galūnes valdantys neuronų tinklai išsidėstę atitinkamai nugaros smegenų kaklinės ir strėnų sričių išplatėjimuose. Disertacijoje parodoma, kad ir krūtininiai nugaros smegenų segmentai prisideda prie užpakalinių galūnių motorinio aktyvumo generavimo. Tai leidžia manyti, kad neuronų tinklas generuojantis judesius yra išplitęs labiau, nei manyta iki šiol.
Fuente, Ruiz Sandra de la. "Development of new therapeutic strategies for Spinal Muscular Atrophy." Doctoral thesis, Universitat de Lleida, 2020. http://hdl.handle.net/10803/669753.
Full textLa atrofia muscular espinal (AME) es una enfermedad neurodegenerativa grave y la primera causa genética de muerte infantil. Se origina por la pérdida o mutación del gen Survival Motor Neuron 1 (SMN1) que causa una deficiencia de la proteína de Survival Motor Neuron (SMN). La reducción de esta proteína conduce predominantemente a la degeneración de las motoneuronas (MNs) de la médula espinal y, en consecuencia, produce atrofia y debilidad del músculo esquelético. Actualmente, solo se conoce parcialmente que mecanismos celulares y moleculares exactos son los responsables de la pérdida de función de las MNs. La reducción de SMN causa degeneración de neuritas y muerte celular sin características apoptóticas clásicas. La autofagia es un proceso importante y altamente regulado, esencial para la eliminación de orgánulos dañados y sustancias o proteínas tóxicas a través de la degradación con los lisosomas. La autofagia es especialmente importante en células post-mitóticas, como las MNs, donde la acumulación de autofagosomas provoca la interrupción del transporte axonal, la interferencia del tráfico intracelular y la degeneración de las neuritas. Lo que es bien sabido en la AME es que el nivel intracelular de proteína SMN define el inicio y la gravedad de la enfermedad y esto está parcialmente determinado por el número de copias del gen SMN2, la duplicación centromérica de SMN y el principal modificador de la AME. Por esa razón, comprender los procesos que regulan la degradación de SMN con la finalidad de identificar compuestos que aumentan los niveles de proteínas es el principal objetivo en el desarrollo terapéutico de AME. Las calpaínas son una familia de proteasas dependientes de calcio que se han relacionado con trastornos musculares y enfermedades neurodegenerativas. Específicamente, se ha descrito en el músculo que SMN puede ser proteolizada por calpaína. La actividad de la calpaína también está involucrada en la regulación de la autofagia mediante la modulación de múltiples de las proteínas involucradas en el proceso. El objetivo en el presente trabajo ha sido analizar la desregulación de la autofagia y determinar la participación de la calpaína en la regulación de la proteína SMN en las MNs para profundizar en el origen de la neurodegeneración y desarrollar un nuevo enfoque terapéutico para la AME. Con este fin, hemos analizado marcadores autofágicos en diferentes modelos in vitro de AME, tanto de ratón como de humano. Los resultados mostraron que los autofagosomas y los niveles de LC3 se encuentran aumentados en las muestras de AME en comparación con los controles, lo que sugiere una desregulación del proceso de autofagia a lo largo de la progresión de la enfermedad. Además, la reducción de los niveles endógenos de calpaína utilizando un shRNA muestraron un aumento de los niveles de Smn y LC3, a la vez que previene la degeneración neuritica que se produce en las MNs de ratón afectados por AME. Se obtuvieron resultados similares en experimentos in vitro utilizando un inhibidor farmacológico de calpaína, la calpeptina. Asimismo, la activación de calpaína producida por condiciones despolarizantes inducia la proteólisis de α-fodrina y de SMN, lo que confirma que calpain regula directamente los niveles de proteína SMN en las MNs. Además, el tratamiento con calpeptina in vivo mejoró significativamente la esperanza de vida y la función motora de dos modelos de ratones con AME, lo que demuestra la utilidad potencial de los inhibidores de la calpaína en la terapia para la enfermedad. Finalmente, el análisis de la vía de la calpaína en ratones y modelos celulares humanos de AME indicó un aumento de la actividad de la calpaína en las MNs con niveles reducidos de SMN. Por lo tanto, nuestros resultados demuestran que la actividad de la calpaína se encuentra sobreactivada en las MNs de AME y su inhibición puede tener un efecto beneficioso sobre el fenotipo de la enfermedad a través del aumento de SMN y la regulación del proceso de autofagia en las MNs de la médula espinal.
Spinal Muscular Atrophy (SMA) is a severe neurodegenerative disease and the first genetic cause of infant death. It is originated by the deletion or mutation of Survival Motor Neuron 1 (SMN1) gene causing a Survival Motor Neuron (SMN) protein deficiency. The reduction of this protein predominantly leads to the degeneration of spinal cord motoneurons (MNs) and consequently produces skeletal muscle atrophy and weakness. The exact cellular and molecular mechanisms responsible for MN loss of function are only partially known. SMN reduction causes neurite degeneration and cell death without classical apoptotic features. Autophagy is an important and highly regulated process, essential for the removal of damaged organelles and toxic substances or proteins through lysosome degradation. This mechanism is specifically important in post-mitotic cells like MNs where autophagosome accumulation causes axonal transport disruption, interference of intracellular space trafficking, and neurite degeneration. What is well known in SMA is that intracellular SMN protein levels are critical to define the disease onset and severity, and this is partially determined by the number of copies of SMN2, the centromeric duplication of the SMN gene and the main modifier of SMA. For that reason, understanding the processes of SMN stability and degradation to identify compounds that increase protein levels is a major goal in SMA therapeutics development. Calpains are a family of calcium-dependent proteases that have been related to muscle disorders and neurodegenerative diseases. Specifically, it has been described in muscle that SMN can be a proteolytic target of calpain. Calpain activity is also involved in autophagy regulation by modulation of multiple proteins involved in the process. The objectives in the present work have been to analyze the autophagy deregulation and determine the involvement of calpain in SMN protein regulation on MNs, in order to deepen in the origin of neurodegeneration and to develop a new therapeutic approach for SMA disease. To this end, we have analyzed autophagic markers in different mouse and human SMA in vitro models. The results showed that autophagosomes and LC3 levels were increased in SMA samples compared to controls, suggesting a deregulation of the autophagy process throughout the disease progression. Moreover, calpain knockdown using an shRNA approach showed an increase of both, Smn and LC3 levels and prevented neurite degeneration occurred in SMA affected mouse MNs. Similar results were obtained in in vitro experiments using a pharmacological calpain inhibitor, calpeptin. Likewise, calpain activation produced by depolarized conditions induced α-fodrin and SMN proteolysis, confirming that calpain directly regulates the SMN protein level in MNs. Additionally, calpeptin in vivo treatment significantly improved the lifespan and motor function of two severe SMA mouse models, demonstrating the potential utility of calpain inhibitors in SMA therapeutics. Finally, the analysis of calpain pathway members in mice and human cellular SMA models indicated an increase of calpain activity in SMN-reduced MNs. Thus, our results show that calpain activity is increased in SMA MNs and its inhibition may have a beneficial effect on the SMA phenotype through the increase of SMN and the regulation of the autophagy process in spinal cord MNs.
Bose, Prodip Kumar. "Wobbler mouse : early detection of motoneuron disease, therapeutic evaluation of nutrition, neuropeptides & their antagonists, and the effects on neuronal sprouting in cervical spinal cord /." Hong Kong : University of Hong Kong, 1997. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19118168.
Full textWalter, Lisa Marie [Verfasser], Peter [Akademischer Betreuer] Claus, Evgeni [Akademischer Betreuer] Ponimaskin, Anaclet [Akademischer Betreuer] Ngezahayo, and Laxman [Akademischer Betreuer] Gangwani. "Dynamics and regulation of the actin cytoskeleton in the motoneuron disease Spinal Muscular Atrophy (SMA) / Lisa Marie Walter ; Peter Claus, Evgeni Ponimaskin, Anaclet Ngezahayo, Laxman Gangwani." Hannover : Stiftung Tierärztliche Hochschule Hannover, 2020. http://d-nb.info/1217249508/34.
Full textZanon, Renata Graciele. "Influencia da modulação da expressão do MHC I sobre a astroglicose reativa e plasticidade sinaptica." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/316479.
Full textTese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: O complexo de histocompatibilidade principal de classe I (MHC I) é uma molécula originalmente do Sistema Imunológico. A presença desses elementos no Sistema Nervoso Central (SNC) parece estar relacionada a diferentes funções, apresentando papel importante no refinamento sináptico durante o desenvolvimento do SNC e sendo fundamental no processo de eliminação sináptica após uma lesão nervosa no adulto. No intuito de investigarmos os processos de plasticidade sináptica e reatividade glial no microambiente da medula espinal foram utilizados dois imunomoduladores empregados no tratamento da Esclerose Múltipla, o interferon beta (IFN beta) e o acetato de glatirâmer (AG). O IFN beta, potencialmente capaz de influenciar a expressão de MHC I, foi utilizado in vivo, juntamente com axotomia periférica e in vitro, enquanto o AG foi utilizado para testes in vitro. Para tanto, camundongos C57BL/6J foram tratados com 10.000 UI de IFN beta durante 2 semanas, antes e depois da transecção unilateral do nervo isquiático. Os camundongos foram submetidos à eutanásia e suas medulas espinais lombares processadas para imunohistoquímica (anti-MHC I, sinaptofisina, GFAP - glial fibrillary acidc protein, ezrina e iba1), hibridação in situ (sondas para GFAP e microglobulina beta-2), Western blotting (GFAP e MHC I) e microscopia eletrônica de transmissão. Grupos axotomizados, placebo e não tratado foram utilizados como controles. Adicionalmente ao estudo in vivo, foram estabelecidas culturas purificadas de astrócitos para o tratamento com diferentes doses de IFN beta (0, 100, 500 ou 1000 UI/ml) ou AG (0, 1.2, 2.5 ou 5.0µg/ml) durante 5 dias. As culturas tratadas com IFN beta foram submetidas à imunohistoquímica para MHC I, ezrina, GFAP, enquanto nas culturas tratadas com AG foi realizado o estudo para verificar a reatividade e proliferação através da marcação anti-GFAP e DAPI (para identificação dos núcleos das células). In vivo, os resultados mostraram um aumento do RNAm e da expressão protéica para MHC I após axotomia, sendo que este incremento foi maior no grupo tratado com INF. Observou-se a intensificação da expressão das proteínas que expressam a reatividade astrocitária, GFAP e ezrina, concomitantemente à diminuição da imunomarcação para sinaptofisina, especialmente no grupo tratado. O tratamento realizado não influenciou a reatividade da microglia. A análise do material in vitro também mostrou, após o tratamento com IFN beta, um aumento da expressão de MHC I e GFAP, bem como de ezrina. As doses que mais estimularam a elevação da expressão dos marcadores estudados foram as de 500 e 1000 UI/ml. Dado que não ocorreu para o tratamento com o acetato de glatirâmer. Assim, o tratamento com AG não alterou o nível de reatividade astrocitária, apesar de estimular a proliferação celular. A ultraestrutura das sinapses mostrou uma intensa retração dos terminais pré-sinápticos em contato com os motoneurônios alfa, induzida pela axotomia mais o tratamento com IFN beta. Em conjunto, esses resultados reforçam a importância da expressão de moléculas de MHC I em resposta à lesão nervosa e seu papel como mecanismo de comunicação entre neurônio e glia, além de reafirmar que os astrócitos são elementos ativos no processo de plasticidade sináptica.
Abstract: The class I main histocompatibility complex (MHC I) is a molecule originally restricted to Immune System. The presence of such element in the Central Nervous System (CNS) may indicate other functions, including an important role in the synaptic refinement during the development of the CNS as well as in the synaptic elimination process after a peripheral nerve injury in the adult. To investigate the synaptic plasticity and glial reactivity in the spinal cord, two immunomodulators, widely used for treating Multiple Sclerosis, were applied, namely the Interferon beta (IFN beta) and the glatiramer acetate (GA). The IFN beta was used in order to upregulate the MHC I expression in vivo, after a peripheral axotomy, and also in vitro. GA treatment was only used for in vitro experiments. C57BL/6J mice were injected with 10,000 IU of IFN beta for 2 weeks, before and after the nerve transection. The animals were sacrificed and the lumbar spinal cords were processed for immunohistochemistry (MHC I, synapthophysin, GFAP, ezrin and Iba-1 antisera), in situ hybridization (beta 2 immunoglobulin, a component of the MHC I molecule, and GFAP), Western blotting (GFAP and MHC I) and transmission electron microscopy. Placebo and non-treated axotomized groups were used as controls. Additionally to the in vivo study, primary cultures of astrocytes were established and treated during five consecutive days with different doses of IFN beta (0, 100 IU, 500 IU and 1000 IU/ml). In this case, some cultures were treated with GA (0, 1.2, 2,5 and 5.0 µg/ml). INF treated cultures were processed for immunocitochemistry (MHC I, GFAP and ezrin antisera). GA treated cultures were evaluated with anti-GFAP antibody and cell proliferation was accessed with DAPI staining. In vivo, the results showed an upregulation of MHC I mRNA and protein expression after axotomy, that was stronger in the IFN treated group. We observed a greater GFAP and ezrin expression, coupled with a decrease of synapthophysin immunoreactivity. Such alterations were more evident in the IFN treated group. Interestingly, the IFN beta treatment did not interfere in the microglial reactivity. The in vitro analysis also showed a sharp upregulation of MHC I, GFAP and ezrin, mostly when the cultures were subjected to 500 and 1000 IU/ml of IFN beta. Regarding the GA treatment, the results showed that treatment did not change the level of astroglial reactivity despite stimulating cellular proliferation. The ultrastructural analysis of synapses showed a larger pruning of presynaptic terminals in contact with alpha motoneurons, induced by axotomy plus IFN beta treatment. Together, our results reinforce the importance of the MHC I expression as a response to nerve injury and its role as a communication mechanism between neurons and surrounding glial cells. Furthermore, the present data confirm that astrocytes are active elements during the synaptic plasticity process.
Doutorado
Anatomia
Biologia Celular e Estrutural
Cerveró, Cebrià Clàudia. "Atròfia muscular espinal: mecanismes patogènics i estratègies terapèutiques en models murins de la malaltia." Doctoral thesis, Universitat de Lleida, 2016. http://hdl.handle.net/10803/399028.
Full textLa atrofia muscular espinal (AME) es una enfermedad genética que cursa con muerte de motoneuronas espinales y atrofia muscular. Se ha caracterizado un modelo murino de AME, el Smn2B/-, con una clínica menos severa que la mostrada por otros modelos más extensamente utilizados. Se ha evidenciado una alteración multisistémica acompañando a la clásicamente conocida del sistema neuromuscular. Se han estudiado las sinapsis colinérgicas de tipo C en la AME y testado el papel del PRE-084 (agonista del receptor sigma-1 presente en estas) como posible terapia en los modelos SMNΔ7 y Smn2B/-. A pesar de no conferir neuroprotección, el PRE-084 ha evitado la gliosis propia de la AME. Finalmente, se ha testado la efectividad del AICAR, agente mimético del ejercicio físico, en ratones SMNΔ7. El AICAR ha mitigado la atrofia muscular, los defectos estructurales en las uniones neuromusculares y la pérdida de sinapsis glutamatérgicas en el soma de las motoneuronas, pero no ha evitado la muerte neuronal ni la reacción glial en la medula espinal.
The spinal muscular atrophy (SMA) is a genetic disease that affects spinal motor neurons causing its death and muscle atrophy. This study is divided in three parts. First. Characterization of the Smn2B/- mice, a mild SMA phenotype model. A multisistemic affectation was reported to accompany the better known neuromuscular alteration in these mice. Second. Study of C-type cholinergic synapses in the SMA and therapeutic trial with the sigma-1 receptor agonist PRE-084 (molecule present in C boutons) in the SMNΔ7 and Smn2B/- mice. Although PRE-084 did not confer neuroprotection, it prevented the SMA characteristic reactive gliosis. Third. Treatment with AICAR, an exercise mimetic agent, in SMNΔ7 mice. AICAR mitigated muscular atrophy and structural defects in neuromuscular junctions and prevented loss of glutamatergic synapses in the motoneuron soma but it did not protect against neuronal death and reactive gliosis.
Guzulaitis, Robertas. "Nugaros smegenų neuronų tinklo veikimo principai: somatosensorinės informacijos integracija ir aktyvumo išplitimas." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2013. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2013~D_20130925_093406-59707.
Full textSpinal cord integrates somatosensory information and generates coordinated motor responses. Temporal integration can be used for discrimination of important stimuli from noise. Here it is shown that temporal integration of somatosensory inputs in sub second time scale is possible without changes of intrinsic properties of motoneurons. The activity of premotor neurons increases during temporal integration and can be a mechanism for short term information storage in spinal cord. Suppression of motor activity after painful somatosensory stimulus is called cutaneous silent period. This motor suppression is well described in humans and used for diagnostics. However it is not known if the suppression of motor activity is due to inhibition of motoneurons or reduction of excitatory drive from premotor neurons. Here it is shown that motoneurons are inhibited during cutaneous silent period. Neural networks of spinal cord not only process somatosensory information but generate locomotion and reflexes too. It is accepted that neural networks controlling front and hind limb movements are located in cervical and lumbar enlargements respectfully. Here it is shown that thoracic segments of spinal cord contribute to hind limb movements as well. It means that neural network generating movements is much more widely distributed than previously thought.
Bouhadfane, Mouloud. "Propriétés électriques bistables des motoneurones de la moelle épinière : Identification des mécanismes ioniques sous-jacents." Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM5030/document.
Full textPosture allowing an erect posture of the body relies on spiking activity of motoneurons innervating antigravitary muscle. Discharge could take the form of plateau potential on mature motoneurons of numerous vertebrates. To determine a possible concordance between the emergence of plateau potential and postural control development, we studied the maturation and ionic nature of plateau potential of motoneurons innervating triceps surae muscle of neonatal rat.The conclusion of our work allows us to propose a fundamental mechanism in the genesis of plateau potential on lumbar motoneurons. This mechanism based on a "ménage a trois" seems to play an important role in the neonatal motor development. This scientific advance could eventually lead to a better understanding of the origin of some sensori-motor impairments (spasticity, hyperalgesia...) and development of therapeutic strategies
Martin, Elodie. "Altérations précoces des réseaux moteurs spinaux chez la souris SOD1, modèle de la Sclérose Latérale Amyotrophique." Thesis, Bordeaux 1, 2013. http://www.theses.fr/2013BOR14873/document.
Full textMost studies based on the use of Amyotrophic Lateral Sclerosis (ALS) mouse models focus on symptomatic or presymptomatic periods. However, morphological alterations of ALS motoneurons have been described in post-natal stages, suggesting that ALS could be a neurodevelopmental disease. In this PhD Thesis, based on the use of the SOD1G93A mouse model of ALS, we tried to know if during the embryonic development of the spinal motoneuronal networks, alterations occur particularly at the level of the maturation of GABA/Glycine inhibition, driven by the chloride homeostasis. Indeed, we believe that a wrong construction of the motor network during the embryonic life may be the cause of the troubles observed at the onset of ALS. Our data show that the morphology of motoneurons is altered in E17,5 SOD1G93A embryos compared to WT embryos and that this changes in morphology induced hyperexcitability. In addition, we show an alteration of the equilibrium potential of chloride ions (ECl) due to a modification of the balance of NKCC1/KCC2 chloride co-transporters. Finally, we tried to know if a modification of the ECl had functional consequences in the development of locomotor activity expressed by the lumbar spinal network. In conclusion, the work of this PhD Thesis demonstrates, for the first time, a developmental deficit in the SOD1G93A mouse model and opens new perspectives based on understanding compensatory mechanisms occuring until the appearance of the disease
Buišas, Rokas. "The gain of spinal cord motoneurons and its modification." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2012. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2012~D_20121001_093711-87354.
Full textMotoneuronai – tai nervinės ląstelės tiesiogiai valdančios raumenis. Motoneuronuose, kaip ir kitose neuronuose, įėjimo transformacija į išėjimą charakterizuojama perdavimo funkcija, kuri dažniausiai aprašoma tam tikro statumo tiesine priklausomybe. Didelis perdavimo funkcijos statumas leidžia išvystyti didelę raumens susitraukimo jėgą, o mažas – įgalina tikslų raumenų valdymą. Perdavimo funkcijos charakteristikas apsprendžia neurono membranoje esantys joniniai kanalai. Pavyzdžiui, veikimo potencialų adaptaciją sukeliantys joniniai kanalai perdavimo funkcijos statumą mažina. Be to, neuroninio tinklo veikimo metu išskirti neurotransmiteriai gali veikti joninius kanalus ir pritaikyti perdavimo funkciją konkretaus judesio vykdymui. Šio darbo tikslas buvo įvertinti nugaros smegenų motoneuronų perdavimo funkcijos ypatybes ir ištirti jos galimus modifikavimo mechanizmus. Tyrimams naudoti vėžlio nugaros smegenų motoneuronai. Disertacijoje parodėme, kad perdavimo funkcijos statumas įvertintas trikampiais srovės impulsais sutampa su stacionariu perdavimo funkcijos statumu, įvertintu stimuliuojant motoneuronus stačiakampiais srovės impulsais. Nustatėme, kad farmakologiškai padidintas motoneuronų membranos laidumas neįtakoja perdavimo funkcijos statumo. Taip pat parodėme, kad nuolatinė Na+ srovė sumažina pradinį ir ankstyvąjį perdavimo funkcijų statumus.
Leroy, Félix. "Atteinte différentielle de deux populations de motoneurones spinaux chez le souriceau SOD1 G93A (modèle de la maladie de Charcot)." Thesis, Paris 5, 2013. http://www.theses.fr/2013PA05T063/document.
Full textIn the second postnatal week, the locomotor behavior of mice changes from crawling to walking. This is made possible by profound changes in motor units. Yet, how the discharge properties of spinal motoneurons evolve during post-‐natal maturation and whether they have an effect on the motor unit maturation remains an open question. In neonates, the spinal motoneurons display two modes of discharge. For threshold pulses, 33% of the motoneurons have a discharge that start at the current onset and adapts during the pulse (“immediate firing motoneurons”). The remaining 66% motoneurons fire with a large delay and the discharge then accelerates throughout the pulse (“delayed firing motoneurons”). Though the delayed firing pattern is quite common in spinal motoneurons of neonates, the ionic mechanisms that elicit this mode of discharge have received little attention. Using the patch-clamp technique to record P6‐P10 mouse motoneurons in a spinal cord slice preparation, I characterized the ionic currents that underlie the delayed firing pattern. This is caused by a combination of an A-like potassium current that acts on a short time scale and a slow‐inactivating potassium current that delays the discharge on a much longer time scale. I then investigated how these two potassium currents contribute to the recruitment threshold and how they shape the F-I function of delayed motoneurons in neonatal mice. The slow inactivating potassium current induces memory effects that have a strong impact on motoneuron excitability and on its discharge. Building on these results, I tried to correlate the discharge pattern to known physiological sub‐types. The delayed firing motoneurons have a larger input conductance, a higher rheobase, a narrower action potential, a shorter AHP and a more complex dendritic arbor than the immediate firing motoneurons. Additionally, only a sub-‐population of the delayed firing motoneurons expressed the chondrolectin protein, a fast motoneuron marker. Based on this body of corroborating evidence, the immediate firing motoneurons would be slow type motoneurons whereas the delayed firing motoneurons would be fast type motoneurons. Finally, numerous electrical and geometrical abnormalities have been observed in spinal motoneurons of SOD1 G934 mice (model of the amyotrophic lateral sclerosis) during the second post-natal week but the results were somehow contradictory. In relation to the known differential sensitivity to the disease exhibited by slow and fast motoneurons, I investigated whether the immediate and delayed firing motoneurons are equally affected by the SOD1 mutation. This is not the case. I found that the SOD1 mutation induced a decrease in the rheobase and a hyperpolarization of the voltage threshold only in the immediate firing motoneurons, thereby making them more excitable than in WT mice. Furthermore, the dendrites of the immediate firing motoneurons are substantially shorter (about 35%) in the mutant than in the WT. In sharp contrast, the excitability of the delayed firing motoneurons is unchanged and the dendritic tree is nearly unaffected (the dendrites only undergo a 10% elongation). These results allow for reconsidering the link between hyperexcitability and degenerescence of the motoneurons
Cisi, Rogério Rodrigues Lima. "Sistema de simulação de circuitos neuronais da medula espinhal desenvolvido em arquitetura web." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/3/3142/tde-31032008-173530/.
Full textThis work describes the development of a simulation system of neuronal circuitry, having a user-friendly interface and based on web architecture. The system is intended for studying spinal cord neuronal networks responsible for muscle control, subjected to descending drive or electrical stimulation. It is potentially useful in many activities, such as the interpretation of electrophysiological experiments conducted with humans, the proposition of hypotheses or theories on neuronal processing. Computer simulation is the most indicated approach to attain the objectives of this project because of the huge number of variables and the non-linear characteristics of the constituting elements. The simulations should mimic in a faithful way the main properties related to the modeled neuronal nuclei. These properties are associated with: i) motor-unit recruitment, ii) neuronal nuclei input-output relations, iii) afferent tract influence on motoneurons, iv) effects of recurrent inhibition and reciprocal inhibition, v) generation of force and electromyogram, and others. The generation of the H-reflex by the Ia-motoneuron pool system, which is an important tool in human neurophysiology, is included in the simulation system. The biological reality obtained with the present simulator and its web-based implementation make it a powerful tool for researchers in neurophysiology.
Benito, González Ana. "V1-DERIVED RENSHAW CELLS AND IA INHIBITORY INTERNEURONS DIFFERENTIATE EARLY DURING DEVELOPMENT." Wright State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=wright1310071181.
Full textBuišas, Rokas. "Nugaros smegenų motoneuronų perdavimo funkcija ir jos modifikavimas." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2012. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2012~D_20121001_093702-49526.
Full textMotoneurons are the spinal neurons that directly control the muscle contraction. The gain characterizes how the synaptic input to motoneuron is converted in to action potential firing and subsequent muscle contraction. The high gain allows a high force and fast contraction, while the low gain is essential for a fine control of movements. The gain of motoneurons is mainly determined by a set of ion channels in membrane and therefore is a subject for modification. It is known, that the gain decreases during adaptation of action potential firing. Moreover, the neurotransmitters released during spinal network activity may modify the ion channel activity and therefore adjust the gain to the functional needs. The aim of this study was to evaluate the gain of spinal cord motoneurons and investigate mechanisms of its modification. Spinal motoneurons from adult turtle were used. We found that the gain of motoneurons estimated from triangular current ramps is the same as steady one obtained from square current steps. Pharmacologically increased conductance of motoneuron membrane does not change the gain. Finally, we demonstrated that persistent inward Na+ current increases excitability and reduces the transient and early gain of spinal motoneurons.
Moran, Linda Bridget. "Synaptic connectivity of normal and axotomised developing rat motoneurons." Thesis, Imperial College London, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.251825.
Full textBair, Woei-Nan. "The convergence of descending motor volleys onto human spinal motoneurons." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq22271.pdf.
Full textDeng, Zhihui. "SMALL CONDUCTANCE CALCIUM-ACTIVATED POTASSIUM (SK) CHANNELS IN MAMMALIAN SPINAL MOTONEURONS." Wright State University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=wright1237821684.
Full textLawson, Simon John. "A morphological study of naturally occuring and induced neuronal death in the developing spinal cord of the rat." Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265974.
Full textWelin, Dag. "Neuroprotection and axonal regeneration after peripheral nerve injury." Doctoral thesis, Umeå : Umeå university, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-32819.
Full textGou, Fàbregas Myriam. "Spinal cord motoneurons,morphological and molecular study during development and pathology." Doctoral thesis, Universitat de Lleida, 2010. http://hdl.handle.net/10803/8105.
Full texta) L'estudi dels mecanismes intracel·lulars dependents de calci que modulen la supervivència de les motoneurones durant el desenvolupament.
Com a efecte inductor de supervivència hem analitzat la participació de la proteïna quinasa dependent de Ca2+/Calmodulina IV (CaMKIV) en motoneurones embrionàries de pollastre, i demostrem que la seva activació calci dependent indueix la fosforilació d'Akt i la supervivència d'aquestes neurones. Per altra banda, com a efecte inductor de mort demostrem que els increments excessius de la concentració del calci intracel·lular induïts per la despolarització de la membrana, són responsables de l'activació de la proteasa Calpaïna i la conseqüent degeneració de les motoneurones de ratolí. Proposem la inhibició de Calpaïna com a mecanisme neuroprotector.
b) La generació d'un model in vitro per a l'estudi dels mecanismes patològics que causen la degeneració específica de les motoneurones en Atròfia Muscular Espinal.
En aquesta segona part del treball, amb la finalitat de contribuir a la comprensió de la fisiopatologia d'aquesta malaltia hem desenvolupat un model in vitro utilitzant tècniques d'interferència d'RNA. Reduïm l'expressió de la proteïna Survival Motoneuron (SMN) en les motoneurones fins a nivells representatius de la forma severa de la malaltia. L'estudi morfològic i de viabilitat en aquestes cèl·lules ens facilitarà la identificació dels mecanismes moleculars implicats en la malaltia.
Els resultats presentats en aquesta tesi impliquen l'activació de CaMKIV en la regulació de la supervivència de les motoneurones; proporcionen nous coneixements sobre les vies de regulació que en provoquen la seva degeneració (nivells de potassi elevats al medi extracel·lular i Calpaïna), i demostren alteracions d'aquestes neurones en un models d'Atròfia Muscular Espinal (degeneració neurítica i mort).
La identificación de los mecanismos moleculares que regulan la supervivencia y muerte de las motoneuronas representa una información importante de conocimiento básico y para el establecimiento de potenciales dianas terapéuticas para las enfermedades que cursan con degeneración y muerte de estas neuronas. Por este motivo hemos dedicado este trabajo al estudio de:
a) Mecanismos intracelulares básicos dependientes de calcio que modulan la supervivencia de las motoneuronas durante el desarrollo.
Como efecto inductor de supervivencia hemos analizado la participación de la proteína quinasa dependiente de Ca2+/Calmodulina IV (CaMKIV) en motoneuronas embrionarias de pollo, y demostramos que su activación calcio dependiente, induce la fosforilación de Akt y supervivencia de estas neuronas. Por otro lado, como a efecto inductor de muerte demostramos que incrementos de la concentración del calcio intracelular inducidos por la despolarización de la membrana, son responsables de la activación de la proteasa Calpaína y la degeneración de las motoneuronas de ratón. Nuestros resultados apoyan el uso de inhibidores de Calpaína como estrategia neuroprotectora.
b) Mecanismos patológicos que causan la degeneración específica de las motoneuronas en Atrofia Muscular Espinal.
En esta segunda parte del trabajo, con la finalidad de contribuir a la comprensión de la fisiopatología de esta enfermedad hemos desarrollado un modelo in Vitro utilizando técnicas de interferencia de RNA. Reducimos la expresión de la proteína Survival Motoneuron (SMN) en las motoneuronas hasta niveles representativos de la forma severa de la enfermedad. El estudio morfológico y de viabilidad en estas células nos facilitará la identificación de los mecanismos moleculares implicados en la enfermedad.
Los resultados que presentamos en esta tesis implican la activación de CaMKIV en la regulación de la supervivencia de las motoneuronas; proporcionan nuevos conocimientos sobre las vías de regulación que provocan su degeneración (niveles de potasio elevados al medio extracelular y Calpaína), así como alteraciones específicas de estas neuronas en modelos de Atrofia Muscular Espinal (degeneración neurítica y muerte).
Identification of molecular mechanisms that regulate motoneuron survival and death represent valuable basic knowledge to elucidate potential therapeutic targets for those diseases that imply motoneuron degeneration and death. For this reason in the present work we studied:
a) Basic calcium-dependent intracellular mechanisms which modulate motoneuron survival during development.
As a pro-survival effect we analysed the role of the calcium/calmodulin dependent protein kinase IV (CaMKIV) in cultured chicken motoneurons. Results demonstrated that CaMKIV activation induces Akt phosphorylation and motoneuron survival. On the other hand, as a prodegenerative effect we demonstrate that in mouse motoneurons depolarization induced excessive calcium influx activates the protease Calpain and causes motoneurons death. Our results suggest that Calpain inhibitors may induce neuroprotective effects.
b) Intrinsic motoneuron pathological mechanisms underlying Spinal Muscular Atrophy.
In this second part, with the aim to facilitate the understanding of the physiopathology of SMA we developed an in vitro model using RNA interference techniques. We reduce Survival Motoneuron (SMN) protein expression in motoneurons to representative levels from severe Spinal Muscular Atrophy mouse models. Morphologic and survival analysis of these cultured neurons may contribute to the identification of pathologic molecular mechanisms implicated in the disease.
Reported results, obtained from the morphological and molecular analysis of primary motoneuron cultures, provide new knowledge on motoneuron development and survival regulating pathways (implication of CaMKIV activation in motoneuron survival regulation), about regulation pathways involved in motoneuron degeneration (high potassium extracellular levels and Calpain activation), as well as motoneuron alterations in a severe SMA culture model (neurite degeneration and death).
Hammarberg, Henrik. "Spinal motoneurons and molecules related to neurotrophic function after axon injury /." Stockholm, 2000. http://diss.kib.ki.se/2000/91-628-3976-4/.
Full textThams, Sebastian. "Immune recognition molecules in synaptic plasticity and regeneration of spinal motoneurons." Stockholm, 2009. http://diss.kib.ki.se/2009/978-91-7409-721-4/.
Full textNascimento, Filipe. "Cholinergic modulation of spinal motoneurons and locomotor control networks in mice." Thesis, University of St Andrews, 2018. http://hdl.handle.net/10023/16141.
Full textDuclos, Yann. "Etude des processus spinaux qui préparent à la réalisation d'un mouvement volontaire chez l'homme : implication précoce des motoneurones dans la préparation motrice." Thesis, Aix-Marseille 2, 2011. http://www.theses.fr/2011AIX20683.
Full textThe aim of this work was to analyze the effects of motor preparation on motoneuron (MN) activity. For this purpose, recordings of wrist extensor muscles motor unit activity were combined with time motor preparation paradigms in Human. Changes in the MN tonic discharge were found to occur during preparatory period, i.e. well before it is time to act. These changes were a lengthening of the mean inter-spike interval associated with a decrease of its variability. These data clearly demonstrate that spinal inhibitory mechanisms are activated during motor preparation and suggest the involvement of premotoneuronal interneurons. The modulations of motoneuronal activity induced by the motor preparation are neither specific to the agonist muscle involved in the motor response nor predictive of the performance. It is assumed that the inhibition acting on the MN during the motor preparation constitutes a general braking mechanism serving to prevent premature motor response, whereas the decrease of discharge variability would be a compensatory phenomenon, allowing to produce an efficient steady force in spite of lower motoneuronal activation. The involvement of the motoneuronal level in motor preparation demonstrates that advance information may influence the state of the motor system, including even the most peripheral motor neurons in the spinal cord, which supports the idea that motor preparation involves highly distributed functional processes. In addition, this work led us to argue in favor of the approximate entropy analysis as a suitable method for analyzing spike trains, allowing to detect changes in the regularity of the time-ordered inter-spikes intervals
Müller, Katja. "Untersuchung der Erregbarkeit spinaler Motoneurone während Propofolmononarkosen." Doctoral thesis, Humboldt-Universität zu Berlin, Medizinische Fakultät - Universitätsklinikum Charité, 2006. http://dx.doi.org/10.18452/15423.
Full textIntroduction: The measurement of „depth of anaesthesia“ is mostly done by parameters of the electroencephalogram (EEG) which can predict hypnosis whereas the prediction of immobility is not possible with those parameters. A previous study has shown that the H-reflex amplitude can be used for monitoring of immobility during sevoflurane anaesthesia. This study examined whether the prediction of movement to painful stimulation is also possible during propofol anaesthesia on the basis of the H-reflex-amplitude compared with the EEG-parameters bispectral index (BIS), spectral entropy (SE) and response entropy (RE). Furthermore the influence of propofol on the H-reflex-recovery under double pulse stimulation was tested. Methods: After approval of the institutional review board and informed consent were obtained, 17 patients were included into this study. Using the “up-and down”-method the concentration of propofol was adjusted to the level where half of the patients do not move to painful stimulation (C50-tetanus-value). Propofol was administered after a baseline measurement. After at least 15 minutes of constant propofol concentration a "steady-state" was assumed and a painful electrical stimulation (tetanic stimulus of 60mA) was applied. To estimate and compare the predictive value of the parameters, prediction probability Pk was calculated. The H-reflex during double pulse stimulation was examined with interstimulus intervals ranging from 50 to 8000 ms. Results: At awake level, H-reflexes had a mean amplitude of 5.9 (+/- 3.8 SD) mV. The calculated C50-tetanus-value was 4.5 (+/- 0.45 SD) mg/l. With Pk-values of 0.47 for the H-reflex amplitude and 0.45 for the heart rate the prediction of movements is just by chance. The Pk-values of the EEG-parameters were higher: BIS (0.74), SE (0.73), RE (0.71). At this level was also the Pk-value of the propofol concentration (0.76). The painful stimulation influenced neither the H-reflex amplitude nor the EEG-parameters. The double pulse stimulation showed a delay in the H-reflex-recovery at interstimulus intervals of 150 and 200 ms. Conclusion: The prediction of movement during propofol anaesthesia is better using the EEG-parameters BIS, SE and RE compared to the H-reflex-amplitude. These results are in contrast to a previous study with sevoflurane which can be explained by the different molecular mechanisms of action of volatile and intravenous anaesthetics. The depression of the recovery-curve of the H-reflex under double pulse stimulation is possibly due to the reduction of supraspinal excitatory influences.
Flaith, Leonie. "Klinik, elektrophysiologische und kernspintomographische Untersuchungen bei adulten Vorderhornerkrankungen." [S.l. : s.n.], 2007. http://nbn-resolving.de/urn:nbn:de:bsz:289-vts-60073.
Full textLenz, Kathryn M. "Mechanisms mediating the effects of maternal care on the masculinization of spinal motoneurons." [Bloomington, Ind.] : Indiana University, 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3380150.
Full textTitle from PDF t.p. (viewed on Jul 20, 2010). Source: Dissertation Abstracts International, Volume: 70-12, Section: B, page: 7839. Advisers: Dale R. Sengelaub; Gregory E. Demas.
Gibbons, Andrew Stuart. "The effects of supplying spinal motoneurons with a constant source of exogenous neurotrophins." Monash University, School of Biological Sciences, 2004. http://arrow.monash.edu.au/hdl/1959.1/9621.
Full textJohnson, Hans. "Spinal motoneurons and the bulbospinal serotoninergic system in aged rats with behavioral deficits /." Stockholm, 1998. http://diss.kib.ki.se/1998/91-628-3277-8/.
Full textChan, Yuen-man, and 陳婉文. "Effect of caspase inhibitors on the survival and regeneration of injured spinal motoneurons." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B31242893.
Full textWidmann, Alexandra. "Quantitative Auswertung spinaler Motoneurone nach intracisternaler Transplantation von Stammzellen in ein Mausmodell der amyotrophen Lateralsklerose." [S.l. : s.n.], 2008. http://nbn-resolving.de/urn:nbn:de:bsz:289-vts-63892.
Full textMacDonald, Stephen Christopher. "Oligodendrocytes and motoneurons, two cholinergic cell types derived from multipotent spinal neuroepithelial precursor cells." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0016/NQ53066.pdf.
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