This work is supported by a Canadian Health Research Institute (CIHR) Team Grant to Dr. Bolduc (co-PI) and Dr. Guy Rouleau (PI). We would like to thank Dr. Oksana Suchowersky, Dr. Kathryn Todd, the members of the University of Alberta fly club and Dr. Clayton Dickson for help in development of the method and statistical analysis.

Pesquisa sobre Drosophila melanogaster estava em conformidade com a Universidade de diretrizes de pesquisa de Alberta. 1. Fly Colecção <ol><li> Coletar 20 moscas usando CO 2 (g) anestesiados e coloque em um frasco de recolha 25 milímetros x 95 milímetros contendo alimentos. </li><li> Frascos contendo loja moscas horizontalmente para evitar a captura de moscas em quaisquer líquidos que podem se acumular no fundo do frasco. </li><li> Incubar moscas durante pelo menos 21 horas a 22 ° C em 45% de humidade num incubador durante aproximadamente durante 15 h. Defina a incubadora com uma luz de 12 horas: ciclo escuro. </li></ol> 2. Escalada Assay <ol><li> Na manhã seguinte, a transferência de 20 moscas a partir de um único frasco num copo de 250 ml cilindro graduado. Marque a posição do cilindro para mantê-lo todos os dias constante. Usar um cilindro de vidro por genótipo para evitar a contaminação cruzada entre os genótipos. Lavar-se ao fim de cada experiência e rolitar-los entre os genótipos. <ol><li> Conduzir as experiências em luz ambiente (ou luz vermelha se houver um defeito potencial na visão) a temperatura e humidade de 22 ° C e 40% respectivamente. Para evitar circadiano confundem ritmo, sempre realizar experimentos na mesma hora do dia. </li></ol></li><li> Selar o topo do cilindro com uma película de barreira (filme de cera) para impedir a fuga de quaisquer moscas (Figura 2). </li><li> Configure a câmera de vídeo em um tripé. Câmera com foco na linha 190 ml dos 250 ml cilindro graduado (17.5 cm). </li><li> Contar o número de moscas mortas na parte inferior do cilindro e nos frascos de alimentos. Grave este número como a mortalidade. </li><li> Muito bata levemente contra o cilindro de uma almofada de espuma de células fechadas, repetidamente, com força suficiente para deslocar as moscas para a superfície de fundo interna. Toque 5-10 vezes enquanto com a outra mão para pressionar registro na câmera. </li><li> Pressione o botão &quot;Record&quot; na câmara. </li><li> Comece o vidEO gravação e câmera toque no cilindro de seis vezes em um padrão não-rítmica distinta. </li><li> Realizar cada julgamento por 2 min do tempo as moscas estão último aproveitado e registrar o número de moscas que atravessam a altura de 17,5 centímetros (190 ml) em cada ponto de tempo escolhido (quantificar a cada 10 segundos). Nota: A marcação no cilindro ml irá variar de um modelo para outro cilindro, dependendo do diâmetro. Para evitar erros, medir a altura de cada cilindro usado. </li><li> Uma vez que o julgamento terminou, dispor de moscas em 95% de etanol. </li><li> Repita os passos 2.1 a 2.9 até que todos os replicados foram testados com moscas fresco de cada vez. Nota: Embora cinco repetições pode ser suficiente, com uma mutação ter um forte efeito na locomoção, 10 réplicas biológicas de 20 moscas, moscas (200) é recomendado para detectar diferenças menores. </li><li> Após a conclusão da experiência, os cilindros de lavagem na máquina de lavar de laboratório e seca O / N para ser re-utilizado. </li></ol> 3. Análise <ol><li> Analyvídeos ze de cada voar julgamento. Cada 10 segundos, anotar o número total de moscas que passam a linha de meta. <ol><li> Se uma mosca sobe de volta para baixo ou cai, registro que voam como -1 e contar a próxima mosca para cruzar a linha de meta como o mesmo número que a mosca que subiu de volta para baixo ou caiu. Por exemplo, se o 15º mosca cai abaixo da linha de meta, a próxima mosca para cruzar a linha (16 th voar) é considerado o 15º mosca e não o 16º. </li></ol></li><li> Subtrair a mortalidade a partir do número total de moscas (20) para se obter o número de moscas que permanecem no ensaio. Em cada ponto de tempo, obter a fracção de moscas acima da linha de destino. </li><li> Traçar cada porcentagem em cada ponto de tempo (ver Figura 3). </li><li> Analisar o desempenho no ponto de dados 120 segundos e realizar teste t de Student quando dois grupos se encontrem presentes ou análise de variância e um pós-teste para comparações múltiplas (com modificação Bonferroni para planejado e Tukey para co não planejadamparisons). O teste de Kolmogorov-Smirnov testa 17 também é realizada para verificar a normalidade e variância igual, mas também para comparar as distribuições do grupo mutante para o controlo. </li><li> Para apresentar os dados sobre o envelhecimento, plotar a porcentagem de moscas subir a 120 segundos com moscas de diferentes idades (2 dias, uma semana, duas semanas) para ver se há um déficit progressivo (Figura 4). </li></ol>

<ol>
	<li>Auluck, P. K., Bonini, N. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pharmacological+prevention+of+Parkinson+disease+in+Drosophila.">Pharmacological prevention of Parkinson disease in Drosophila.</a> Nature medicine. 8, 1185-1186 (2002).</li><li>Bonini, N. M., Fortini, M. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+neurodegenerative+disease+modeling+using+Drosophila.">Human neurodegenerative disease modeling using Drosophila.</a> Annual review of neuroscience. 26, 627-656 (2003).</li><li>Bolduc, F. V., Bell, K., Cox, H., Broadie, K. S., Tully, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Excess+protein+synthesis+in+Drosophila+fragile+X+mutants+impairs+long-term+memory.">Excess protein synthesis in Drosophila fragile X mutants impairs long-term memory.</a> Nature neuroscience. 11, 1143-1145 (2008).</li><li>McBride, S. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pharmacological+rescue+of+synaptic+plasticity,+courtship+behavior,+and+mushroom+body+defects+in+a+Drosophila+model+of+fragile+X+syndrome.">Pharmacological rescue of synaptic plasticity, courtship behavior, and mushroom body defects in a Drosophila model of fragile X syndrome.</a> Neuron. 45, 753-764 (2005).</li><li>Parker, L., Padilla, M., Du, Y., Dong, K., Tanouye, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drosophila+as+a+model+for+epilepsy:+bss+is+a+gain-of-function+mutation+in+the+para+sodium+channel+gene+that+leads+to+seizures.">Drosophila as a model for epilepsy: bss is a gain-of-function mutation in the para sodium channel gene that leads to seizures.</a> Genetics. 187, 523-534 (2011).</li><li>Marley, R., Baines, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Increased+persistent+Na++current+contributes+to+seizure+in+the+slamdance+bang-sensitive+Drosophila+mutant.">Increased persistent Na+ current contributes to seizure in the slamdance bang-sensitive Drosophila mutant.</a> Journal of neurophysiology. 106, 18-29 (2011).</li><li>Benzer, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Behavioral+Mutants+Of+Drosophila+Isolated+By+Countercurrent+Distribution.">Behavioral Mutants Of Drosophila Isolated By Countercurrent Distribution.</a> Proceedings of the National Academy of Sciences of the United States of America. 58, 1112-1119 (1967).</li><li>Ganetzky, B., Flanagan, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=On+the+relationship+between+senescence+and+age-related+changes+in+two+wild-type+strains+of+Drosophila+melanogaster.">On the relationship between senescence and age-related changes in two wild-type strains of Drosophila melanogaster.</a> Experimental gerontology. 13, 189-196 (1978).</li><li>Nichols, C. D., Becnel, J., Pandey, U. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Methods+to+assay+Drosophila+behavior.">Methods to assay Drosophila behavior.</a> Journal of visualized experiments : JoVE. , (2012).</li><li>Toma, D. P., White, K. P., Hirsch, J., Greenspan, R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+of+genes+involved+in+Drosophila+melanogaster+geotaxis,+a+complex+behavioral+trait.">Identification of genes involved in Drosophila melanogaster geotaxis, a complex behavioral trait.</a> Nature genetics. 31, 349-353 (2002).</li><li>Inagaki, H. K., Kamikouchi, A., Ito, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Methods+for+quantifying+simple+gravity+sensing+in+Drosophila+melanogaster.">Methods for quantifying simple gravity sensing in Drosophila melanogaster.</a> Nature protocols. 5, 20-25 (2010).</li><li>Gargano, J. W., Martin, I., Bhandari, P., Grotewiel, M. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+iterative+negative+geotaxis+(RING):+a+new+method+for+assessing+age-related+locomotor+decline+in+Drosophila.">Rapid iterative negative geotaxis (RING): a new method for assessing age-related locomotor decline in Drosophila.</a> Experimental gerontology. 40, 386-395 (2005).</li><li>Botella, J. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Drosophila+carbonyl+reductase+sniffer+prevents+oxidative+stress-induced+neurodegeneration.">The Drosophila carbonyl reductase sniffer prevents oxidative stress-induced neurodegeneration.</a> Current biology : CB. 14, 782-786 (2004).</li><li>Feany, M. B., Bender, W. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Drosophila+model+of+Parkinson's+disease.">A Drosophila model of Parkinson's disease.</a> Nature. 404, 394-398 (2000).</li><li>Chakraborty, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+a+Drosophila+Alzheimer's+disease+model:+pharmacological+rescue+of+cognitive+defects.">Characterization of a Drosophila Alzheimer's disease model: pharmacological rescue of cognitive defects.</a> PLoS One. 6, e20799 (2011).</li><li>Orso, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Disease-related+phenotypes+in+a+Drosophila+model+of+hereditary+spastic+paraplegia+are+ameliorated+by+treatment+with+vinblastine.">Disease-related phenotypes in a Drosophila model of hereditary spastic paraplegia are ameliorated by treatment with vinblastine.</a> J Clin Invest. 115, 3026-3034 (2005).</li><li>Lehmann, E. L., D'Abrera, H. J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Nonparametrics : statistical methods based on ranks. , (2006).</li><li>Sherwood, N. T., Sun, Q., Xue, M., Zhang, B., Zinn, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Drosophila+spastin+regulates+synaptic+microtubule+networks+and+is+required+for+normal+motor+function.">Drosophila spastin regulates synaptic microtubule networks and is required for normal motor function.</a> PLoS biology. 2, e429 (2004).</li><li>Inlow, J. K., Restifo, L. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+and+comparative+genetics+of+mental+retardation.">Molecular and comparative genetics of mental retardation.</a> Genetics. 166, 835-881 (2004).</li><li>Palladino, M. J., Hadley, T. J., Ganetzky, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Temperature-sensitive+paralytic+mutants+are+enriched+for+those+causing+neurodegeneration+in+Drosophila.">Temperature-sensitive paralytic mutants are enriched for those causing neurodegeneration in Drosophila.</a> Genetics. 161, 1197-1208 (2002).</li></ol>

The authors have nothing to disclose.

Drosophila já provou ser um excelente modelo de doença 14 e outras condições neurodegenerativas 1,2 de Parkinson. Além das ferramentas genéticas disponíveis em Drosophila, o seu genoma é altamente conservada em genes envolvidos em desordens neurológicas 19. O advento da largura métodos de rastreio genético do genoma (incluindo exome sequenciamento completo) é provável que continue a fornecer uma lista maior de genes candidatos associados com distúrbios do ...

Doenças neurodegenerativas tais como a doença devastadora de Parkinson, esclerose lateral amiotrófica, e paraplegia espástica hereditária são cada vez mais reconhecidas. Infelizmente, a maioria desses distúrbios neurodegenerativos são ainda sem tratamentos. O uso clínico generalizado de testes genéticos, imparciais de todo o genoma, tais como sequenciação de toda exome levou a um aumento do número de genes implicados em distúrbios locomotiva humanos. Apesar deste progresso, a progressão patológica desde cedo a fases tardias, permanece indefinida nesses transtornos. Drosophila fornece um com as ferramentas genéticas para estudar exigência gene de uma forma temporal e espacial controlada. Além disso, Drosophila tem se mostrado útil na triagem de drogas para doenças neurológicas como Parkinson 1, a doença de Alzheimer 2, deficiência mental e epilepsia 3,4 5,6 entre outros. O nosso objectivo foi desenvolver um custo eficaze ensaio de confiança que permita a análise de alto rendimento que ainda seria suficientemente sensível para detectar pequenas mudanças no desempenho do motor. Existem vários ensaios utilizados para quantificar os efeitos da mutação genética e / ou condições ambientais sobre o comportamento de escalada de Drosophila. A maioria dos ensaios capitalizar a tendência natural das moscas para escalar, conhecidos como geotaxis negativos, ou o ensaio de escalada. Benzer 7 em 1967 sugeriram que o aparelho em contracorrente utilizada para o estudo de fototaxia também poderia ser usado para estudar gravitaxis. Desde então, Ganetsky 8 e muitos outros 9 -12 construíram no ensaio inicial. O princípio é o de colocar um número conhecido de moscas em um frasco e o frasco toque fortemente contra uma superfície dura, fazendo com que as moscas a cair para o fundo do frasco. Como se trata de um comportamento inato, as moscas vai tentar subir para a parte superior do frasco, em oposição à gravidade. Este ensaio é quantitativa e measures quantas moscas subiram passado um marcador no frasco durante um período de tempo estipulado. Medição da velocidade, em vez do número total de moscas escalada tornou-se um parâmetro fiável e mostrado defeitos nos casos em que o número de parâmetros de moscas não foi significativa 13. O ensaio de escalada provou ser útil no estudo de muitas doenças neurodegenerativas, incluindo a doença de Parkinson 14. No entanto, observou-se que os defeitos locomotiva pode não ser detectável no momento em que a neurodegeneração já é visto em estudos patológicos 14. Assim, a utilização do ensaio tradicional pode limitar a capacidade para estudar os estágios iniciais da patogénese da doença. O aparecimento de defeitos locomotiva durante fases posteriores da patologia pode refletir uma doença cuja progressão é muito avançado para resgate completo. Isto levanta um problema potencial com a sensibilidade do ensaio escalada tradicional. A incapacidade potencial do tradicional subir ensaio para detectar defeitos leves locomotiva pode ser atribuído à altura a que as moscas são obrigados a subir. Os tradicionais 15,16 ensaio mede o número de moscas para escalar com sucesso através de uma altura de 2 a 5 cm em 10 a 20 seg.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>Drosophila stocks</td>
			<td></td>
			<td></td>
			<td>The stocks are selected depending on the experiments. The temperature and humidity in the room and in the incubator must be controled and consistent to avoid flies being too staticky or too wet.</td>
		</tr>
		<tr>
			<td>Video camera</td>
			<td></td>
			<td></td>
			<td>Any digital camcorder will do. Make sure they can focus on close object.</td>
		</tr>
		<tr>
			<td>Graduated cylinder</td>
			<td>Kimble</td>
			<td>20028W</td>
			<td>Different models of graduated cylinder may have different diameter. It is therefore imporant to measure the height.</td>
		</tr>
		<tr>
			<td>computer</td>
			<td></td>
			<td></td>
			<td>Any model will do. We used the computer to monitor the climbing of the flies and record the number of flies at each time point</td>
		</tr>
	</tbody>
</table>

quantitative analysis of climbing defects in a drosophila model of neurodegenerative disorders

Locomotiva defeitos resultantes de doenças neurodegenerativas pode ser um início dos sintomas da doença de tarde, após anos de degeneração subclínica, e, assim, estratégias atuais de tratamento terapêutico não são curativos. Através da utilização de sequenciação exome conjunto, um número cada vez maior de genes foram identificados a desempenhar um papel na locomoção humana. Apesar de identificar estes genes, não se sabe como esses genes são cruciais para o funcionamento normal locomotiva. Por conseguinte, um ensaio de confiança, que utiliza organismos modelo para elucidar o papel destes genes, a fim de identificar novos alvos de interesse terapêutico, é necessário mais do que nunca. Nós preparámos uma versão sensibilizado do ensaio geotaxis negativos que permite a detecção de defeitos leves anterior e tem a capacidade de avaliar esses defeitos ao longo do tempo. O ensaio é realizado em um cilindro de vidro graduado, que é selada com uma película de barreira de cera. Ao aumentar a distância patamar de ser escalado para 17,5 cm e aumentando a duração da experiência para 2 min temos observado uma maior sensibilidade na detecção de disfunções de mobilidade suaves. O ensaio é rentável e não requer a formação extensa para obter resultados altamente reprodutíveis. Isso o torna uma excelente técnica para o rastreio de drogas candidatas em mutantes de Drosophila com defeitos de locomoção.

Escalada é um comportamento forte e reprodutível. Na verdade, um dia velhos moscas do tipo selvagem alcançar o desempenho escalada distância do alvo rapidamente (25-30 seg). Moscas mutantes apresentam uma série de desempenho de leve (ou retardada) para completar a incapacidade de subir ao alvo. Nós ilustramos esta aqui com dois alelos mutantes diferentes. O primeiro é um alelo grave do Spastin gene causada por uma deleção completa do gene Spastin spas (5,75) 18. Nesta linha (5,75 spas com ...

Watch this Scientific Journal Video about Quantitative Analysis of Climbing Defects in a Drosophila Model of Neurodegenerative Disorders at JoVE.com

Quantitative Analysis of Climbing Defects in a Drosophila Model of Neurodegenerative Disorders

We present an optimized inexpensive and reliable negative geotaxis assay in Drosophila melanogaster as a model for neurodegenerative disorders. Being more sensitive to mild locomotor defects, this assay will help screen for potential genetic interactions and drug targets.

Análise Quantitativa de Defeitos de escalada em um modelo de Drosophila de doenças neurodegenerativas

Locomotive defects resulting from neurodegenerative disorders can be a late onset symptom of disease, following years of subclinical degeneration, and ...

quantitative-analysis-climbing-defects-drosophila-model

Universidad de Cartagena UDEC

Research

JoVE Journal

Neuroscience

18.5K visualizações.  University of Alberta. We present an optimized inexpensive and reliable negative geotaxis assay in Drosophila melanogaster as a model for neurodegenerative disorders. Being more sensitive to mild locomotor defects, this assay will help screen for potential genetic interactions and drug targets. 

Vídeo: Quantitative Analysis of Climbing Defects in a Drosophila Model of Neurodegenerative Disorders

Quantitative Analysis of Synaptic Vesicle Pool Replenishment in Cultured Cerebellar Granule Neurons using FM Dyes

After neurotransmitter release in central nerve terminals, SVs are rapidly retrieved by endocytosis. Retrieved SVs are then refilled with neurotransmitter and rejoin the recycling pool, defined as SVs that are available for exocytosis1,2. The recycling pool can generally be subdivided into two distinct pools - the readily releasable pool (RRP) and the reserve pool (RP). As their names imply, the RRP consists of SVs that are immediately available for fusion while RP SVs are released only during intense stimulation1,2. It is important to have a reliable assay that reports the differential replenishment of these SV pools in order to understand 1) how SVs traffic after different modes of endocytosis (such as clathrin-dependent endocytosis and activity-dependent bulk endocytosis) and 2) the mechanisms controlling the mobilisation of both the RRP and RP in response to different stimuli.
FM dyes are routinely employed to quantitatively report SV turnover in central nerve terminals3-8. They have a hydrophobic hydrocarbon tail that allows reversible partitioning in the lipid bilayer, and a hydrophilic head group that blocks passage across membranes. The dyes have little fluorescence in aqueous solution, but their quantum yield increases dramatically when partitioned in membrane9. Thus FM dyes are ideal fluorescent probes for tracking actively recycling SVs. The standard protocol for use of FM dye is as follows. First they are applied to neurons and are taken up during endocytosis (Figure 1). After non-internalised dye is washed away from the plasma membrane, recycled SVs redistribute within the recycling pool. These SVs are then depleted using unloading stimuli (Figure 1). Since FM dye labelling of SVs is quantal10, the resulting fluorescence drop is proportional to the amount of vesicles released. Thus, the recycling and fusion of SVs generated from the previous round of endocytosis can be reliably quantified.
Here, we present a protocol that has been modified to obtain two additional elements of information. Firstly, sequential unloading stimuli are used to differentially unload the RRP and the RP, to allow quantification of the replenishment of specific SV pools. Secondly, each nerve terminal undergoes the protocol twice. Thus, the response of the same nerve terminal at S1 can be compared against the presence of a test substance at phase S2 (Figure 2), providing an internal control. This is important, since the extent of SV recycling across different nerve terminals is highly variable11.
Any adherent primary neuronal cultures may be used for this protocol, however the plating density, solutions and stimulation conditions are optimised for cerebellar granule neurons (CGNs)12,13.

A live fluorescence imaging technique to quantify the replenishment and mobilisation of specific synaptic vesicle (SV) pools in central nerve terminals is described. Two rounds of SV recycling are monitored in the same nerve terminals providing an internal control.

Análise quantitativa de Reposição da vesícula sináptica Piscina em Cultured neurônios granulares do cerebelo usando Dyes FM

After neurotransmitter release in central nerve terminals, SVs are rapidly retrieved by endocytosis.  Retrieved SVs are then refilled with ...

Neurociência

Ex vivo Culturing of Whole, Developing Drosophila Brains

We describe a method for ex vivo culturing of whole Drosophila brains. This can be used as a counterpoint to chronic genetic manipulations for investigating the cell biology and development of central brain structures by allowing acute pharmacological interventions and live imaging of cellular processes. As an example of the technique, prior work from our lab1 has shown that a previously unrecognized subcellular compartment lies between the axonal and somatodendritic compartments of axons of the Drosophila central brain. The development of this compartment, referred to as the axon initial segment (AIS)2, was shown genetically to depend on the neuron-specific cyclin-dependent kinase, Cdk5. We show here that ex vivo treatment of wild-type Drosophila larval brains with the Cdk5-specific pharmacological inhibitors roscovitine and olomoucine3 causes acute changes in actin organization, and in localization of the cell-surface protein Fasciclin 2, that mimic the changes seen in mutants that lack Cdk5 activity genetically.
A second example of the ex vivo culture technique is provided for remodeling of the connections of embryonic mushroom body (MB) gamma neurons during metamorphosis from larva to adult. The mushroom body is the center of olfactory learning and memory in the fly4, and these gamma neurons prune their axonal and dendritic branches during pupal development and then re-extend branches at a later timepoint to establish the adult innervation pattern5. Pruning of these neurons of the MB has been shown to occur via local degeneration of neurite branches6, by a mechanism that is triggered by ecdysone, a steroid hormone, acting at the ecdysone receptor B17, and that is dependent on the activity of the ubiquitin-proteasome system6. Our method of ex vivo culturing can be used to interrogate further the mechanism of developmental remodeling. We found that in the ex vivo culture setting, gamma neurons of the MB recapitulated the process of developmental pruning with a time course similar to that in vivo. It was essential, however, to wait until 1.5 hours after puparium formation before explanting the tissue in order for the cells to commit irreversibly to metamorphosis; dissection of animals at the onset of pupariation led to little or no metamorphosis in culture. Thus, with appropriate modification, the ex vivo culture approach can be applied to study dynamic as well as steady state aspects of central brain biology.

Ex vivo Culturing of Whole, Developing Drosophila Brains

This article describes a method by which one can mimic in vivo development of the Drosophila mushroom body in an ex vivo culture system.

A cultura Ex vivo de todo, o desenvolvimento cerebral de Drosophila

We describe a method for ex vivo culturing of whole Drosophila brains. This can be used as a counterpoint to chronic genetic manipulations for ...

Assessing Neurodegenerative Phenotypes in Drosophila Dopaminergic Neurons by Climbing Assays and Whole Brain Immunostaining

Drosophila melanogaster is a valuable model organism to study aging and pathological degenerative processes in the nervous system. The advantages of the fly as an experimental system include its genetic tractability, short life span and the possibility to observe and quantitatively analyze complex behaviors. The expression of disease-linked genes in specific neuronal populations of the Drosophila brain, can be used to model human neurodegenerative diseases such as Parkinson's and Alzheimer's 5.
Dopaminergic (DA) neurons are among the most vulnerable neuronal populations in the aging human brain. In Parkinson's disease (PD), the most common neurodegenerative movement disorder, the accelerated loss of DA neurons leads to a progressive and irreversible decline in locomotor function. In addition to age and exposure to environmental toxins, loss of DA neurons is exacerbated by specific mutations in the coding or promoter regions of several genes. The identification of such PD-associated alleles provides the experimental basis for the use of Drosophila as a model to study neurodegeneration of DA neurons in vivo. For example, the expression of the PD-linked human &alpha;-synuclein gene in Drosophila DA neurons recapitulates some features of the human disease, e.g. progressive loss of DA neurons and declining locomotor function 2. Accordingly, this model has been successfully used to identify potential therapeutic targets in PD 8.
Here we describe two assays that have commonly been used to study age-dependent neurodegeneration of DA neurons in Drosophila: a climbing assay based on the startle-induced negative geotaxis response and tyrosine hydroxylase immunostaining of whole adult brain mounts to monitor the number of DA neurons at different ages. In both cases, in vivo expression of UAS transgenes specifically in DA neurons can be achieved by using a tyrosine hydroxylase (TH) promoter-Gal4 driver line 3, 10.

Assessing Neurodegenerative Phenotypes in Drosophila Dopaminergic Neurons by Climbing Assays and Whole Brain Immunostaining

Here we describe two assays that have been established to study age-dependent neurodegeneration of dopaminergic (DA) neurons in Drosophila: the climbing/startle-induced negative geotaxis assay which allows to study the functional effects of DA neurons degeneration and the tyrosine hydroxylase immunostaining which is used to identify and count DA neurons in whole brain mounts.

Avaliando fenótipos Neurodegenerativas em<em&gt; Drosophila</em&gt; Neurônios dopaminérgicos subindo Ensaios e toda Imunocoloração Cérebro

Drosophila melanogaster is a valuable model organism to study aging and pathological degenerative processes in the nervous system. The advantages of the ...

Fast Micro-iontophoresis of Glutamate and GABA: A Useful Tool to Investigate Synaptic Integration

One of the fundamental interests in neuroscience is to understand the integration of excitatory and inhibitory inputs along the very complex structure of the dendritic tree, which eventually leads to neuronal output of action potentials at the axon. The influence of diverse spatial and temporal parameters of specific synaptic input on neuronal output is currently under investigation, e.g. the distance-dependent attenuation of dendritic inputs, the location-dependent interaction of spatially segregated inputs, the influence of GABAergig inhibition on excitatory integration, linear and non-linear integration modes, and many more.
With fast micro-iontophoresis of glutamate and GABA it is possible to precisely investigate the spatial and temporal integration of glutamatergic excitation and GABAergic inhibition. Critical technical requirements are either a triggered fluorescent lamp, light-emitting diode (LED), or a two-photon scanning microscope to visualize dendritic branches without introducing significant photo-damage of the tissue. Furthermore, it is very important to have a micro-iontophoresis amplifier that allows for fast capacitance compensation of high resistance pipettes. Another crucial point is that no transmitter is involuntarily released by the pipette during the experiment.
Once established, this technique will give reliable and reproducible signals with a high neurotransmitter and location specificity. Compared to glutamate and GABA uncaging, fast iontophoresis allows using both transmitters at the same time but at very distant locations without limitation to the field of view. There are also advantages compared to focal electrical stimulation of axons: with micro-iontophoresis the location of the input site is definitely known and it is sure that only the neurotransmitter of interest is released. However it has to be considered that with micro-iontophoresis only the postsynapse is activated and presynaptic aspects of neurotransmitter release are not resolved. In this article we demonstrate how to set up micro-iontophoresis in brain slice experiments.

In this article we introduce fast micro-iontophoresis of neurotransmitters as a technique to investigate integration of postsynaptic signals with high spatial and temporal precision.

Rápido Micro-iontoforese de glutamato e GABA: uma ferramenta útil para investigar Integração Synaptic

One of the fundamental interests in neuroscience is to understand the integration of excitatory and inhibitory inputs along the very complex structure of ...

Deriving the Time Course of Glutamate Clearance with a Deconvolution Analysis of Astrocytic Transporter Currents

The highest density of glutamate transporters in the brain is found in astrocytes. Glutamate transporters couple the movement of glutamate across the membrane with the co-transport of 3 Na+ and 1 H+ and the counter-transport of 1 K+. The stoichiometric current generated by the transport process can be monitored with whole-cell patch-clamp recordings from astrocytes. The time course of the recorded current is shaped by the time course of the glutamate concentration profile to which astrocytes are exposed, the kinetics of glutamate transporters, and the passive electrotonic properties of astrocytic membranes. Here we describe the experimental and analytical methods that can be used to record glutamate transporter currents in astrocytes and isolate the time course of glutamate clearance from all other factors that shape the waveform of astrocytic transporter currents. The methods described here can be used to estimate the lifetime of flash-uncaged and synaptically-released glutamate at astrocytic membranes in any region of the central nervous system during health and disease.

We describe an analytical method to estimate the lifetime of glutamate at astrocytic membranes from electrophysiological recordings of glutamate transporter currents in astrocytes.

Derivando o Curso momento do desembaraço glutamato com uma Análise de Deconvolução das correntes Transporter astrocitárias

The highest density of glutamate transporters in the brain is found in astrocytes. Glutamate transporters couple the movement of glutamate across the ...

High-Resolution Quantitative Immunogold Analysis of Membrane Receptors at Retinal Ribbon Synapses

Retinal ganglion cells (RGCs) receive excitatory glutamatergic input from bipolar cells. Synaptic excitation of RGCs is mediated postsynaptically by NMDA receptors (NMDARs) and AMPA receptors (AMPARs). Physiological data have indicated that glutamate receptors at RGCs are expressed not only in postsynaptic but also in perisynaptic or extrasynaptic membrane compartments. However, precise anatomical locations for glutamate receptors at RGC synapses have not been determined. Although a high-resolution quantitative analysis of glutamate receptors at central synapses is widely employed, this approach has had only limited success in the retina. We developed a postembedding immunogold method for analysis of membrane receptors, making it possible to estimate the number, density and variability of these receptors at retinal ribbon synapses. Here we describe the tools, reagents, and the practical steps that are needed for: 1) successful preparation of retinal fixation, 2) freeze-substitution, 3) postembedding immunogold electron microscope (EM) immunocytochemistry and, 4) quantitative visualization of glutamate receptors at ribbon synapses.

The postembedding immunogold method is one of the most effective ways to provide high-resolution analyses of the subcellular localization of specific molecules. Here we describe a protocol to quantitatively analyze glutamate receptors at retinal ribbon synapses.

High-Resolution Análise Quantitativa immunogold de Receptores de Membrana na retina fita Sinapses

Retinal ganglion cells (RGCs) receive excitatory glutamatergic input from bipolar cells. Synaptic excitation of RGCs is mediated postsynaptically by NMDA ...

Analyzing Synaptic Modulation of Drosophila melanogaster Photoreceptors after Exposure to Prolonged Light

The nervous system has the remarkable ability to adapt and respond to various stimuli. This neural adjustment is largely achieved through plasticity at the synaptic level. The Active Zone (AZ) is the region at the presynaptic membrane that mediates neurotransmitter release and is composed of a dense collection of scaffold proteins. AZs of Drosophila melanogaster (Drosophila) photoreceptors undergo molecular remodeling after prolonged exposure to natural ambient light. Thus the level of neuronal activity can rearrange the molecular composition of the AZ and contribute to the regulation of the functional output.
Starting from the light exposure set-up preparation to the immunohistochemistry, this protocol details how to quantify the number, the spatial distribution, and the delocalization level of synaptic molecules at AZs in Drosophila photoreceptors. Using image analysis software, clusters of the GFP-fused AZ component Bruchpilot were identified for each R8 photoreceptor (R8) axon terminal. Detected Bruchpilot spots were automatically assigned to individual R8 axons. To calculate the distribution of spot frequency along the axon, we implemented a customized software plugin. Each axon&#39;s start-point and end-point were manually defined and the position of each Bruchpilot spot was projected onto the connecting line between start and end-point. Besides the number of Bruchpilot clusters, we also quantified the delocalization level of Bruchpilot-GFP within the clusters. These measurements reflect in detail the spatially resolved synaptic dynamics in a single neuron under different environmental conditions to stimuli.

Analyzing Synaptic Modulation of Drosophila melanogaster Photoreceptors after Exposure to Prolonged Light

Here we show how to quantify the number and spatial distribution of synaptic active zones in Drosophila melanogaster&#160;photoreceptors, highlighted with a genetically encoded molecular marker, and their modulation after prolonged exposure to light.

Analisando Synaptic Modulação da<em&gt; Drosophila melanogaster</em&gt; Fotorreceptores após exposição à luz prolongada

The nervous system has the remarkable ability to adapt and respond to various stimuli. This neural adjustment is largely achieved through plasticity at ...

The Use of Trace Eyeblink Classical Conditioning to Assess Hippocampal Dysfunction in a Rat Model of Fetal Alcohol Spectrum Disorders

Neonatal rats were administered a relatively high concentration of ethyl alcohol (11.9% v/v) during postnatal days 4-9, a time when the fetal brain undergoes rapid organizational change and is similar to accelerated brain changes that occur during the third trimester in humans. This model of fetal alcohol spectrum disorders (FASDs) produces severe brain damage, mimicking the amount and pattern of binge-drinking that occurs in some pregnant alcoholic mothers. We describe the use of trace eyeblink classical conditioning (ECC), a higher-order variant of associative learning, to assess long-term hippocampal dysfunction that is typically seen in alcohol-exposed adult offspring. At 90 days of age, rodents were surgically prepared with recording and stimulating electrodes, which measured electromyographic (EMG) blink activity from the left eyelid muscle and delivered mild shock posterior to the left eye, respectively. After a 5 day recovery period, they underwent 6 sessions of trace ECC to determine associative learning differences between alcohol-exposed and control rats. Trace ECC is one of many possible ECC procedures that can be easily modified using the same equipment and software, so that different neural systems can be assessed. ECC procedures in general, can be used as diagnostic tools for detecting neural pathology in different brain systems and different conditions that insult the brain.

Trace eyeblink classical conditioning (ECC) was used to assess hippocampal-dependent associative learning in adult rats that were administered a high concentration (11.9% v/v) of alcohol during early neonatal brain development. In general, ECC procedures are sound diagnostic tools for detecting brain dysfunction across many psychological and biomedical settings.

O uso do condicionamento de rastreamento Eyeblink clássico para avaliar disfunção Hippocampal em um modelo do rato de transtornos do espectro do álcool Fetal

Neonatal rats were administered a relatively high concentration of ethyl alcohol (11.9% v/v) during postnatal days 4-9, a time when the fetal brain ...

Assessment of Blood-brain Barrier Permeability by Intravenous Infusion of FITC-labeled Albumin in a Mouse Model of Neurodegenerative Disease

Disruption of blood-brain barrier (BBB) integrity is a common feature for different neurological and neurodegenerative diseases. Although the interplay between perturbed BBB homeostasis and the pathogenesis of brain disorders needs further investigation, the development and validation of a reliable procedure to accurately detect BBB alterations may be crucial and represent a useful tool for potentially predicting disease progression and developing targeted therapeutic strategies.
Here, we present an easy and efficient procedure for evaluating BBB leakage in a neurodegenerative condition like that occurring in a preclinical mouse model of Huntington disease, in which defects in the permeability of BBB are clearly detectable precociously in the disease. Specifically, the high molecular weight fluorescein isothiocyanate labelled (FITC)-albumin, which is able to cross the BBB only when the latter is impaired, is acutely infused into a mouse jugular vein and its distribution in the vascular or parenchymal districts is then determined by fluorescence microscopy.
Accumulation of green fluorescent-albumin in the brain parenchyma functions as an index of aberrant BBB permeability and, when quantitated by using Image J processing software, is reported as Green Fluorescence Intensity.

In this study, we present an easy and efficient procedure for evaluating the disruption of the blood-brain barrier under neurodegenerative conditions. To achieve our objective, we infused high molecular weight fluorescein isothiocyanate labelled (FITC)-albumin into mouse jugular vein and evaluated its leakage into the brain parenchyma by fluorescence microscopy.

Avaliação da permeabilidade da barreira hemato - encefálica por infusão intravenosa de albumina FITC-etiquetadas em um modelo do rato da doença neurodegenerativa

Disruption of blood-brain barrier (BBB) integrity is a common feature for different neurological and neurodegenerative diseases. Although the interplay ...

Quantitative Analysis of Neuronal Dendritic Arborization Complexity in Drosophila

Dendrites are the branched projections of a neuron, and dendritic morphology reflects synaptic organization during the development of the nervous system. Drosophila larval neuronal dendritic arborization (da) is an ideal model for studying morphogenesis of neural dendrites and gene function in the development of nervous system. There are four classes of da neurons. Class IV is the most complex with a branching pattern that covers almost the entire area of the larval body wall. We have previously characterized the effect of silencing the Drosophila ortholog of SOX5 on class IV neuronal dendritic arborization complexity (NDAC) using four parameters: the length of dendrites, the surface area of dendrite coverage, the total number of branches, and the branching structure. This protocol presents the workflow of NDAC quantitative analysis, consisting of larval dissection, confocal microscopy, and image analysis procedures using ImageJ software. Further insight into da neuronal development and its underlying mechanisms will improve the understanding of neuronal function and provide clues about the fundamental causes of neurological and neurodevelopmental disorders.

Quantitative Analysis of Neuronal Dendritic Arborization Complexity in Drosophila

This protocol focuses on quantitative analysis of neuronal dendritic arborization complexity (NDAC) in Drosophila, which can be used for studies of dendritic morphogenesis.

Análise quantitativa da arborização dendrítica Neuronal complexidade em Drosophila

Dendrites are the branched projections of a neuron, and dendritic morphology reflects synaptic organization during the development of the nervous system. ...

Análise Quantitativa de Defeitos de escalada em um modelo de Drosophila de doenças neurodegenerativas

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