Los autores desean agradecer a Mateo Florencia para la preparación de los cultivos de cortes de hipocampo. Este trabajo fue apoyado por becas de EE.UU. Instituto Nacional sobre el Envejecimiento y la Asociación de Alzheimer para NZG.

1. Fijación Los fijadores son cancerígenos; use guantes y manejar los fijadores en una campana de humos. A menos que se indique lo contrario, todas las incubaciones se realizan sobre hielo y todas las soluciones debe ser filtrado antes de su uso. El uso de electrones microscopía de grado-reactivos. Día 1 <ol><li class="jove_content"> Después de condiciones experimentales (por ejemplo, inyección viral, el tratamiento farmacológico), colocar la membrana con organotípicos de cortes de hipocampo en un 60 x 15 mm de poliestireno placa de Petri que contiene enfriado con hielo 0,1 M de tampón fosfato (tampón fosfato de Sorensen), pH 7,3. Añadir 1 a 2 ml de tampón fosfato 0,1 M directamente en la parte superior de las rodajas para mantenerlos fríos. </li></ol> PASO FUNDAMENTAL: Siempre use amortiguadores recién preparados y fijadores. Asegúrese de que el pH del tampón está dentro del rango deseado. El hecho de no hacerlo puede dañar las estructuras celulares. <ol start="2"><li> Para aislar el subcampo CA1 de la rebanada, utilizar undesechable bisturí para cortar suavemente a través de la porción próxima a la DG, paralela a la capa de células CA1 (Figura 1). A continuación, corte la porción restante verticalmente para eliminar el subcampo CA3 y la subículo. Cortar una esquina de la rebanada para ayudar a identificar la superficie superior del tejido. </li></ol> NOTA: En caso de no entrega viral de la proteína de interés se requiere, la lámina de tejido entero puede ser fijado después de que el soporte se extrae con un enjuagado suave de tampón enfriado con hielo. Esto es seguido por corte de la CA1. Paso crítico: un seguimiento de la parte superior del tejido con el fin de seccionamiento adecuado de las rejillas más adelante. <ol start="3"><li> Retire cuidadosamente el tejido de la membrana utilizando la parte trasera del bisturí. Utilizar una pipeta Pasteur para transferir suavemente el tejido a una placa de 12-pocillos que contenía 0,1 M de tampón fosfato. </li><li> Eliminar el tampón en el pocillo de la placa y añadir 500 &amp; mu; l - 1 ml de helado de fijador (pH 7,3) compuesto de los siguientes: 0,1% de ácido pícrico, 1% de paraformaldehído, y 2,5% de glutaraldehído en 0,1 M tampón fosfato. Incubar durante 2 horas a 4 ° C. </li></ol> NOTA: El ácido pícrico puede ser explosivo cuando está seco. Manténgalo humedecido con agua en un recipiente herméticamente cerrado. Guárdelo en un lugar seco y bien ventilado. <ol start="5"><li> Retire el fijador del pozo y lavar las muestras 3 veces (20 min cada uno) en 0,1 M tampón fosfato. </li><li> Incubar durante 40 min en 1% de ácido tánico (w / v) en tampón de maleato 0,1 M, pH 6,0. </li><li> Enjuague dos veces (20 min cada una) en tampón de maleato. </li><li> Incubar durante 40 min en acetato de uranilo al 1% (w / v) en tampón de maleato en la oscuridad. Acetato de uranilo es sensible a la luz y es radiactivo. Cubrir el vaso con Parafilm cuando se disuelve y almacenar cualquier tampón utilizado en la oscuridad a 4 ° C. </li><li> Enjuague dos veces (20 min cada una) en tampón de maleato. </li><li> Incubar durante 20 min en cloro platino 0,5%ide (w / v) en tampón de maleato. </li><li> Enjuague dos veces (20 min cada una) en tampón de maleato. Almacenar las muestras a 4 º C hasta que estén listos para su posterior procesamiento. </li></ol> 2. La deshidratación y la incrustación El óxido de propileno es cancerígeno. Evite los vapores al trabajar con ella en una campana de humos. El uso de etanol absoluto, 100% puro que no contiene ninguna traza de agua. Diluir esta etanol absoluto para producir diferentes concentraciones de deshidratación. Día 2 <ol><li> Incubar durante 5 min en etanol al 50% y después de 5 min en etanol al 70%. </li><li> Incubar durante 15 min en 1% recién preparada p-fenilendiamina (PPD) en 70% de etanol. </li><li> Enjuague tres veces en etanol al 70%. </li><li> Incubar durante 5 min en 80% de etanol y después de 5 min en etanol al 95%. </li><li> Incubar en 100% de etanol dos veces 5 min cada uno. </li><li> Preparar viales de vidrio con tapón de rosca y asegúrese de que estén limpios y completamente secos. Transferir las rebanadas a viales de vidrio yetiquetar cada vial simple y clara. </li><li> Incubar durante 5 min en 1:1 etanol: óxido de propileno. </li><li> Incubar en óxido de propileno 100% dos veces 5 min cada uno. </li><li> Añadir resina (Epon) a cada vial para hacer una mezcla 1:1 con óxido de propileno. Mezclar suavemente durante 2 horas. No agite los viales demasiado rigurosa para evitar las burbujas que puedan interferir con incrustación. </li><li> Añadir resina para hacer una mezcla 3:1 con óxido de propileno, y se mezcla durante 2 h. </li><li> Traslado al 100% de resina e incubar S / N. </li></ol> Día 3 <ol start="12"><li> Muestras Sandwich entre tiras de plástico ACLAR y cura durante 24 horas a 60 º C. </li></ol> 3. De sección y de montaje en Grids Día 4 <ol><li> Cortar semi-delgadas (0,5 micras) y las secciones se tiñen con azul de toluidina al 1% + 1% de bórax para determinar la orientación correcta de muestras. </li><li> Cortar secciones ultrafinas (60 nm) y montar en rejillas de níquel, una sección por la red. </li></ol>4. La inmunohistoquímica Todos los tampones y el agua debe ser filtrada antes de su uso. Día 5 <ol><li> Colocar una gota (~ 50 l) de tampón de Tween-20/phosphate 1% (T / PB), pH 7,5, en un trozo de Parafilm limpias sobre una superficie plana. Suavemente levante el grid con pinzas limpias por el borde y flotar en el búfer, sección hacia abajo, y se incuba durante 10 minutos a temperatura ambiente. </li><li> Drenar el exceso de líquido de la red mediante la colocación de lado de la sección hacia arriba sobre papel de filtro y, a continuación flotan en 50 mM de glicina en T / PB durante 15 min a RT. </li></ol> PASO FUNDAMENTAL: Para evitar la excesiva &quot;carry-over&quot; de soluciones de gota solución de una a otra durante las incubaciones, drenar el exceso de líquido tocando suavemente el borde de la red # 1 en papel de filtro entre cada cambio de solución. También quite cualquier solución atrapado entre los brazos de la EM Pinzas de sujeción de la red por capilaridad suavemente con un trozo de papel de filtro entre los brazos de pinzas mientras ensutocar las partes no se sequen completamente. <ol start="3"><li> Secar la rejilla con papel de filtro y, a continuación flotan en la solución de bloqueo que contiene 2,5% de BSA y 2,5% el suero del animal del anticuerpo secundario en T / PB durante 30 min a RT. </li><li> Incubar con anticuerpo primario (en T / PB) a TA o O / N a 4 º C. El tiempo óptimo y la temperatura de incubación, así como la concentración de anticuerpos, necesita ser determinado experimentalmente. </li><li> Lavar la rejilla de tres veces (2 min cada una) con T / PB. </li><li> Incubar con anticuerpo secundario (1:20 anti-conejo o anti-ratón acoplado a oro nm 10) durante 1 hora a RT. </li><li> Lavar tres veces (2 min cada una) con T / PB. </li><li> Postfix con 2% de glutaraldehído en T / PB durante 5 min. </li><li> Lavar tres veces (2 min cada una) con T / PB y luego tres veces (2 min cada una) con agua filtrada. </li><li> Incubar con acetato de uranilo al 2% en agua durante 10 min. </li></ol> Aunque la red está manchando, prepare un CO 2-cámara libre por placingc trozo de Parafilm en el centro de una placa Petri de vidrio. A continuación, coloque 4-6 pastillas de NaOH en el plato todo el Parafilm para absorber el CO 2 en el aire. Mantener la parte superior cerrada durante unos pocos minutos. Utilizar una pipeta Pasteur y transferir rápidamente un pequeño volumen de solución de citrato de plomo de Reynold para la Parafilm en el plato Petri de vidrio. Abrir la tapa lo suficiente para insertar la pipeta Pasteur para minimizar la re-introducción de CO 2 en la cámara. NOTA: Para hacer una solución de citrato de plomo de Reynold, hervir 100 ml de agua desionizada en un horno de microondas y dejar enfriar en un recipiente hermético. En un matraz aforado de 50 ml con tapón, mezcla de 1,33 g de nitrato de plomo, 1,76 g de citrato sódico y 30 ml de agua hervida agitando vigorosamente durante 1 min. Luego agitar intermitentemente durante 30 min. A esta solución turbia, añadir 8 ml de hidróxido de sodio 1 M y lentamente invertir el matraz varias veces. Solución se hará claro. Llevar la solución a 50 ml con el wa hervidater. Guarde la solución cerrado herméticamente. Si aparece precipitado, desechar y hacer uno nuevo. <ol start="11"><li> En tres vasos más pequeños preparar agua caliente, desionizada recién hervida. Lavar el acetato de uranilo por inmersión de la rejilla en el primer vaso de precipitados y suavemente remolino alrededor de 30 seg. Repita este paso en los otros dos vasos de precipitados. </li><li> Abrir la parte superior de la cápsula Petri de vidrio sólo lo suficiente para colocar la rejilla en la gota de solución de citrato de plomo de Reynold. Si es posible, use una mascarilla mientras se hace esto para evitar respirar el citrato de plomo y evitar la formación de precipitado. Incubar durante 10 min. </li><li> Abra la tapa lo suficiente para quitar la rejilla. Evite respirar el citrato de plomo. Lavar la rejilla tres veces por inmersión secuencial en tres vasos de precipitados con agua tibia, destilada recién hervida. Que la rejilla seco en un trozo de papel de filtro, sección hacia arriba. La muestra está ahora lista para el microscopio electrónico. </li></ol>

<ol>
	<li>Faulk, W. P., Taylor, G. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+immunocolloid+method+for+the+electron+microscope.">An immunocolloid method for the electron microscope.</a> Immunochemistry. 8, 1081-1083 (1971).</li><li>Stirling, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immuno-+and+affinity+probes+for+electron+microscopy:+a+review+of+labeling+and+preparation+techniques.">Immuno- and affinity probes for electron microscopy: a review of labeling and preparation techniques.</a> J. Histochem. Cytochem. 38, 145-157 (1990).</li><li>Phend, K. D., Weinberg, R. J., Rustioni, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Techniques+to+optimize+post-embedding+single+and+double+staining+for+amino+acid+neurotransmitters.">Techniques to optimize post-embedding single and double staining for amino acid neurotransmitters.</a> Journal of Histochemistry &amp; Cytochemistry. 40, 1011-1020 (1992).</li><li>Berryman, 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=Effects+of+tannic+acid+on+antigenicity+and+membrane+contrast+in+ultrastructural+immunocytochemistry.">Effects of tannic acid on antigenicity and membrane contrast in ultrastructural immunocytochemistry.</a> J. Histochem. Cytochem. 40, 845-857 (1992).</li><li>Akagi, T., 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=Improved+methods+for+ultracryotomy+of+CNS+tissue+for+ultrastructural+and+immunogold+analyses.">Improved methods for ultracryotomy of CNS tissue for ultrastructural and immunogold analyses.</a> J. Neurosci. Methods. 153, 276-282 (2006).</li><li>Stirling, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrastructual+localization+of+lysozyme+in+human+colon+eosinophils+using+the+protein+A-gold+technique:+effects+of+processing+on+probe+distribution.">Ultrastructual localization of lysozyme in human colon eosinophils using the protein A-gold technique: effects of processing on probe distribution.</a> J. Histochem. Cytochem. 37, 709-714 (1989).</li><li>Phend, K. D., Rustioni, A., Weinberg, 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=An+osmium-free+method+of+epon+embedment+that+preserves+both+ultrastructure+and+antigenicity+for+post-embedding+immunocytochemistry.">An osmium-free method of epon embedment that preserves both ultrastructure and antigenicity for post-embedding immunocytochemistry.</a> Journal of Histochemistry &amp; Cytochemistry. 43, 283-292 (1995).</li><li>Zhong, L., Cherry, T., Bies, C. E., Florence, M. A., Gerges, N. Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neurogranin+enhances+synaptic+strength+through+its+interaction+with+calmodulin.">Neurogranin enhances synaptic strength through its interaction with calmodulin.</a> Embo J. 28, 3027-3039 (2009).</li><li>Zhong, L., Kaleka, K. S., Gerges, N. Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neurogranin+phosphorylation+fine-tunes+long-term+potentiation.">Neurogranin phosphorylation fine-tunes long-term potentiation.</a> Eur. J. Neurosci. 33, 244-250 (2011).</li><li>Zhong, L., Gerges, N. Z. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neurogranin+targets+calmodulin+and+lowers+the+threshold+for+the+induction+of+long-term+potentiation.">Neurogranin targets calmodulin and lowers the threshold for the induction of long-term potentiation.</a> PloS one. 7, e41275 (2012).</li><li>Horisberger, M., Vauthey, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Labelling+of+colloidal+gold+with+protein.+A+quantitative+study+using+beta-lactoglobulin.">Labelling of colloidal gold with protein. A quantitative study using beta-lactoglobulin.</a> Histochemistry. 80, 13-18 (1984).</li><li>Bendayan, 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+review+of+the+potential+and+versatility+of+colloidal+gold+cytochemical+labeling+for+molecular+morphology.">A review of the potential and versatility of colloidal gold cytochemical labeling for molecular morphology.</a> Biotech. Histochem. 75, 203-242 (2000).</li><li>Racz, B., Weinberg, 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=Spatial+organization+of+coflin+in+dendritic+spines.">Spatial organization of coflin in dendritic spines.</a> J. Neuroscience. 138 (2), 447-456 (2006).</li><li>Posthuma, G., Slot, J. W., Geuze, H. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Usefulness+of+the+immunogold+technique+in+quantitation+of+a+soluble+protein+in+ultra-thin+sections.">Usefulness of the immunogold technique in quantitation of a soluble protein in ultra-thin sections.</a> J. Histochem. Cytochem. 35, 405-410 (1987).</li><li>Howell, K. E., Reuter-Carlson, U., Devaney, E., Luzio, J. P., Fuller, S. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=One+antigen,+one+gold?+A+quantitative+analysis+of+immunogold+labeling+of+plasma+membrane+5'-nucleotidase+in+frozen+thin+sections.">One antigen, one gold? A quantitative analysis of immunogold labeling of plasma membrane 5'-nucleotidase in frozen thin sections.</a> Eur. J. Cell Biol. 44, 318-327 .</li><li>Yokota, E., Kawaguchi, T., Kusaba, T., Niho, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=[Immunologic+analysis+of+families+with+complement+receptor+deficiency].">[Immunologic analysis of families with complement receptor deficiency].</a> Nihon. Rinsho. 46, 2040-2045 (1988).</li><li>Kehle, T., Herzog, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Interactions+between+protein-gold+complexes+and+cell+surfaces:+a+method+for+precise+quantitation.">Interactions between protein-gold complexes and cell surfaces: a method for precise quantitation.</a> Eur. J. Cell Biol. 45, 80-87 (1987).</li><li>Bozzola, J. R., Lonnie, <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ch.+2.">Ch. 2.</a> Electron Microscopy. 30, (1992).</li><li>Cho, K. O., Hunt, C. A., Kennedy, M. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+rat+brain+postsynaptic+density+fraction+contains+a+homolog+of+the+Drosophila+discs-large+tumor+suppressor+protein.">The rat brain postsynaptic density fraction contains a homolog of the Drosophila discs-large tumor suppressor protein.</a> Neuron. 9, 929-942 (1992).</li><li>Hunt, C. A., Schenker, L. J., Kennedy, M. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=PSD-95+is+associated+with+the+postsynaptic+density+and+not+with+the+presynaptic+membrane+at+forebrain+synapses.">PSD-95 is associated with the postsynaptic density and not with the presynaptic membrane at forebrain synapses.</a> J. Neurosci. 16, 1380-1388 (1996).</li><li>Gispen, W. H., Leunissen, J. L., Oestreicher, A. B., Verkleij, A. J., Zwiers, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Presynaptic+localization+of+B-50+phosphoprotein:+the+(ACTH)-sensitive+protein+kinase+substrate+involved+in+rat+brain+polyphosphoinositide+metabolism.">Presynaptic localization of B-50 phosphoprotein: the (ACTH)-sensitive protein kinase substrate involved in rat brain polyphosphoinositide metabolism.</a> Brain Research. 328, 381-385 (1985).</li><li>Biewenga, J. E., Schrama, L. H., Gispen, W. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Presynaptic+phosphoprotein+B-50/GAP-43+in+neuronal+and+synaptic+plasticity.">Presynaptic phosphoprotein B-50/GAP-43 in neuronal and synaptic plasticity.</a> Acta Biochim. Pol. 43, 327-338 (1996).</li><li>Maunsbach, A. A., Bjorn, <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ch.+16.">Ch. 16.</a> Biomedical Electron Microscopy Illustrated Methods and Interpretations. , 383-426 (1999).</li></ol>

No tenemos nada que revelar.

En este protocolo, hemos adoptado el método Phend y Weinberg para el cerebro y los tejidos de la médula espinal para estudiar las espinas dendríticas en las culturas de ratas rebanada hipocampo. Las espinas dendríticas en el hipocampo CA3-CA1 área son delicadas estructuras que contienen una gran variedad de proteínas que desempeñan papeles importantes en la regulación de las funciones neuronales. El método presentado proporciona un enfoque equilibrado para lograr la antigenicidad mayor manteniendo al mismo tiem...

<table border="1">
 <tbody>
 <tr>
 <td>NAME OF REAGENT</td>
 <td>COMPANY</td>
 <td>CATALOG NUMBER</td>
 <td></td>
 </tr>
 <tr>
 <td>60 x 15 mm polystyrene Petri dish</td>
 <td>Falcon</td>
 <td>351007</td>
 <td></td>
 </tr>
 <tr>
 <td>Disposable scalpel</td>
 <td>EXELINT</td>
 <td>29552</td>
 <td></td>
 </tr>
 <tr>
 <td>Cell culture inserts</td>
 <td>Millipore</td>
 <td>PICM03050</td>
 <td></td>
 </tr>
 <tr>
 <td>10 nm Goat-anti-rabbit gold</td>
 <td>Electron Microscopy Sciences</td>
 <td>25108</td>
 <td></td>
 </tr>
 <tr>
 <td>Anti-Neurogranin antibody</td>
 <td>Millipore</td>
 <td>AB5620</td>
 <td></td>
 </tr>
 <tr>
 <td>100% Picric acid</td>
 <td>Electron Microscopy Sciences</td>
 <td>19550</td>
 <td></td>
 </tr>
 <tr>
 <td>96% Paraformaldehyde</td>
 <td>Acros Organics</td>
 <td>AC41678-0030</td>
 <td></td>
 </tr>
 <tr>
 <td>25% Glutaraldehyde (EM grade)</td>
 <td>Sigma</td>
 <td>G5882</td>
 <td></td>
 </tr>
 <tr>
 <td>Uranyl acetate</td>
 <td>Electron Microscopy Sciences</td>
 <td>22400</td>
 <td></td>
 </tr>
 <tr>
 <td>p-Phenylenediamine</td>
 <td>Sigma</td>
 <td>P6001</td>
 <td></td>
 </tr>
 <tr>
 <td>Platinum (IV) chloride</td>
 <td>Sigma</td>
 <td>379840</td>
 <td></td>
 </tr>
 <tr>
 <td>Tannic acid</td>
 <td>Electron Microscopy Sciences</td>
 <td>21710</td>
 <td></td>
 </tr>
 </tbody>
</table>

post-embedding immunogold labeling of synaptic proteins in hippocampal slice cultures

Inmunomicroscopía es una herramienta poderosa para estudiar moléculas biológicas a nivel subcelular. Anticuerpos acoplados a marcadores densos en electrones tales como oro coloidal puede revelar la localización y distribución de antígenos específicos en diversos tejidos 1. Las dos técnicas más utilizadas son las técnicas de incrustación de pre-y post-inmersión. En inmuno-electrónica pre-incrustación de microscopía (EM) técnicas, el tejido debe ser permeabilizan para permitir la penetración de anticuerpos antes de que sea incorporado. Estas técnicas son ideales para la conservación de estructuras, pero pobre penetración del anticuerpo (a menudo sólo los pocos micrómetros primera) es un inconveniente considerable 2. Los métodos de marcaje post-incrustación puede evitar este problema, ya que el etiquetado se lleva a cabo en secciones de tejidos fijados donde los antígenos son más fácilmente accesibles. A través de los años, un número de modificaciones han mejorado los métodos de incrustación de post-inmunoreactividad para mejorar y preservar la ultraestructura <sup&gt; 3-5. Fijación tisular es una parte crucial de los estudios de EM. Fijadores químicamente reticular las macromoléculas para bloquear las estructuras de tejido en su lugar. La elección del fijador no sólo afecta a la conservación estructural, sino también la antigenicidad y el contraste. El tetróxido de osmio (OsO 4), formaldehído, glutaraldehído y han sido los fijadores estándar durante décadas, incluyendo para el sistema nervioso central (SNC) tejidos que son especialmente propensos a daños estructurales durante el tratamiento químico y físico. Desafortunadamente, OsO 4 es altamente reactivo y se ha demostrado para enmascarar antígenos 6, resultando en el etiquetado pobre e insuficiente. Enfoques alternativos para evitar la fijación química incluyen la congelación de los tejidos. Pero estas técnicas son difíciles de realizar y requieren instrumentación costosa. Para resolver algunos de estos problemas y para mejorar el etiquetado CNS tejido, Phend et al. reemplazado Oso 4 con acetato de uranilo (UA) y tánico acid (TA), introducido con éxito y modificaciones adicionales para mejorar la sensibilidad de detección del antígeno y la conservación estructural en tejidos del cerebro y la médula espinal 7. Hemos adoptado esta osmio sin post-incrustación método de tejido cerebral de rata y optimizado la técnica de inmuno-etiquetado para detectar y estudiar las proteínas sinápticas. Se presenta aquí un método para determinar la localización ultraestructural de las proteínas sinápticas del hipocampo de rata en las neuronas piramidales CA1. Utilizamos organotípicos rebanadas de hipocampo en cultivo. Estas rodajas mantener la circuitería trisynaptic del hipocampo, y por lo tanto son especialmente útiles para el estudio de la plasticidad sináptica, un mecanismo ampliamente cree que la base de aprendizaje y memoria. Organotípicos rebanadas de hipocampo de días postnatales 5 y 6 de ratón / rata cachorros se pueden preparar como se ha descrito previamente 8, y son especialmente útiles para agudamente desmontables o sobreexpresan proteínas exógenas. Anteriormente hemos utilizado este protocolo para characterize neurogranina (Ng), una proteína específica de neuronas con un papel crítico en la regulación de la función sináptica 8,9. También lo hemos utilizado para caracterizar la localización ultraestructural de la calmodulina (CaM) y Ca 2 + / CaM dependiente de la proteína quinasa II (CaMKII) 10. Como se ilustra en los resultados, este protocolo permite una buena conservación ultraestructural de las espinas dendríticas y el etiquetado eficiente de Ng para ayudar a caracterizar su distribución en la columna 8. Además, el procedimiento aquí descrito puede tener una amplia aplicación en el estudio de muchas otras proteínas que participan en las funciones neuronales.

La Figura 2B muestra un ejemplo de la distribución de moléculas endógenas NG en las espinas dendríticas de las neuronas piramidales CA1 del hipocampo. Rejillas de níquel con ultrafinos (60 nm) tejidos que contienen la región CA1 del hipocampo (como se ve en la Figura 2A) se trataron en 1% T / PB, 50 mM glicina, luego se bloquearon con 2,5% de BSA y 2,5% de suero antes de la incubación con anti anticuerpo-Ng. Después de lavar con T / PB, rejillas se cubrieron entonces en anti-con...

Watch this Scientific Journal Video about Post-embedding Immunogold Labeling of Synaptic Proteins in Hippocampal Slice Cultures at JoVE.com

Post-embedding Immunogold Labeling of Synaptic Proteins in Hippocampal Slice Cultures

La localización y distribución de proteínas proporcionan información importante para entender sus funciones celulares. La resolución espacial superior de la microscopía electrónica (EM) se puede utilizar para determinar la localización subcelular de un antígeno dado después de inmunohistoquímica. Para los tejidos del sistema nervioso central (SNC), la preservación de la integridad estructural, mientras que el mantenimiento de la antigenicidad ha sido especialmente difícil en los estudios de EM. Aquí, se adopta un procedimiento que ha sido utilizado para preservar las estructuras y los antígenos en el SNC para estudiar y caracterizar proteínas sinápticas del hipocampo de rata en las neuronas piramidales CA1.

Post-Etiquetado Inmunoelectrónica incorporación de proteínas sinápticas en cultivos de cortes de hipocampo

Immunoelectron microscopy is a powerful tool to study biological molecules at the subcellular level. Antibodies coupled to electron-dense markers such as ...

post-embedding-immunogold-labeling-synaptic-proteins-hippocampal

Research

JoVE Journal

Neuroscience

17.0K vistas.  Medical College of Wisconsin. La localización y distribución de proteínas proporcionan información importante para entender sus funciones celulares. La resolución espacial superior de la microscopía electrónica (EM) se puede utilizar para determinar la localización subcelular de un antígeno dado después de inmunohistoquímica. Para los tejidos del sistema nervioso central (SNC), la preservación de la integridad estructural, mientras que el mantenimiento de la antigenicidad ha sido especialm...

Video: Post-embedding Immunogold Labeling of Synaptic Proteins in Hippocampal Slice Cultures

Preparation of Oligomeric &beta;-amyloid1-42 and Induction of Synaptic Plasticity Impairment on Hippocampal Slices

Impairment of synaptic connections is likely to underlie the subtle amnesic changes occurring at the early stages of Alzheimer s Disease (AD). &beta;-amyloid (A&beta;), a peptide produced in high amounts in AD, is known to reduce Long-Term Potentiation (LTP), a cellular correlate of learning and memory. Indeed, LTP impairment caused by A&beta; is a useful experimental paradigm for studying synaptic dysfunctions in AD models and for screening drugs capable of mitigating or reverting such synaptic impairments. Studies have shown that A&beta; produces the LTP disruption preferentially via its oligomeric form. Here we provide a detailed protocol for impairing LTP by perfusion of oligomerized synthetic A&beta;1-42 peptide onto acute hippocampal slices. In this video, we outline a step-by-step procedure for the preparation of oligomeric A&beta;1-42. Then, we follow an individual experiment in which LTP is reduced in hippocampal slices exposed to oligomerized A&beta;1-42 compared to slices in a control experiment where no A&beta;1-42 exposure had occurred.

Preparation of Oligomeric &amp;#946;-amyloid1-42 and Induction of Synaptic Plasticity Impairment on Hippocampal Slices

One feature of Alzheimer's Disease is the elevation of A&beta;1-42 peptide. Here we provide a protocol for preparing synthetic A&beta;1-42 oligomers, which impairs hippocampal Long-Term Potentiation, a cellular correlate of memory. This procedure is useful for investigating mechanisms of A&beta;-induced pathology and drug screening.

Preparación de oligómeros β-amiloide 1-42 Y la inducción del deterioro de plasticidad sináptica en rodajas de hipocampo

Impairment of synaptic connections is likely to underlie the subtle amnesic changes occurring at the early stages of Alzheimer s Disease (AD). ...

Investigación

Neurociencias

The Organotypic Hippocampal Slice Culture Model for Examining Neuronal Injury

Organotypic hippocampal slice culture is an in vitro method to examine mechanisms of neuronal injury in which the basic architecture and composition of the hippocampus is relatively preserved 1. The organotypic culture system allows for the examination of neuronal, astrocytic and microglial effects, but as an ex vivo preparation, does not address effects of blood flow, or recruitment of peripheral inflammatory cells. To that end, this culture method is frequently used to examine excitotoxic and hypoxic injury to pyramidal neurons of the hippocampus, but has also been used to examine the inflammatory response. Herein we describe the methods for generating hippocampal slice cultures from postnatal rodent brain, administering toxic stimuli to induce neuronal injury, and assaying and quantifying hippocampal neuronal death.

The organoptypic hippocampal slice culture model is an in vitro model used to examine neuronal injury in a variety of paradigms. In this article, we describe the methods for generating slice cultures and quantifying neuronal injury.

El organotípicos rebanada hipocampo modelo de cultivo para el examen de la lesión neuronal

Organotypic hippocampal slice culture is an in vitro method to examine mechanisms of neuronal injury in which the basic architecture and composition of ...

Organotypic Hippocampal Slice Cultures

The hippocampus, a component of the limbic system, plays important roles in long-term memory and spatial navigation 1. Hippocampal neurons can modify the strength of their connections after brief periods of strong activation. This phenomenon, known as long-term potentiation (LTP) can last for hours or days and has become the best candidate mechanism for learning and memory 2. In addition, the well defined anatomy and connectivity of the hippocampus 3 has made it a classical model system to study synaptic transmission and synaptic plasticity4.
As our understanding of the physiology of hippocampal synapses grew and molecular players became identified, a need to manipulate synaptic proteins became imperative. Organotypic hippocampal cultures offer the possibility for easy gene manipulation and precise pharmacological intervention but maintain synaptic organization that is critical to understanding synapse function in a more naturalistic context than routine culture dissociated neurons methods.
Here we present a method to prepare and culture hippocampal slices that can be easily adapted to other brain regions. This method allows easy access to the slices for genetic manipulation using different approaches like viral infection 5,6 or biolistics 7. In addition, slices can be easily recovered for biochemical assays 8, or transferred to microscopes for imaging 9 or electrophysiological experiments 10.

We describe a method to prepare organotypic hippocampal slices that can be easily adapted to other brain regions. Brain slices are laid on porous membranes and culture media is allowed to form an interface. This method preserves the gross architecture of the hippocampus for up to 2 weeks in culture.

Organotípicos culturas rebanada hipocampo

The hippocampus, a component of the limbic system, plays important roles in long-term memory and spatial navigation 1. Hippocampal neurons can modify the ...

The Analysis of Purkinje Cell Dendritic Morphology in Organotypic Slice Cultures

Purkinje cells are an attractive model system for studying dendritic development, because they have an impressive dendritic tree which is strictly oriented in the sagittal plane and develops mostly in the postnatal period in small rodents 3. Furthermore, several antibodies are available which selectively and intensively label Purkinje cells including all processes, with anti-Calbindin D28K being the most widely used. For viewing of dendrites in living cells, mice expressing EGFP selectively in Purkinje cells 11 are available through Jackson labs. Organotypic cerebellar slice cultures cells allow easy experimental manipulation of Purkinje cell dendritic development because most of the dendritic expansion of the Purkinje cell dendritic tree is actually taking place during the culture period 4. We present here a short, reliable and easy protocol for viewing and analyzing the dendritic morphology of Purkinje cells grown in organotypic cerebellar slice cultures. For many purposes, a quantitative evaluation of the Purkinje cell dendritic tree is desirable. We focus here on two parameters, dendritic tree size and branch point numbers, which can be rapidly and easily determined from anti-calbindin stained cerebellar slice cultures. These two parameters yield a reliable and sensitive measure of changes of the Purkinje cell dendritic tree. Using the example of treatments with the protein kinase C (PKC) activator PMA and the metabotropic glutamate receptor 1 (mGluR1) we demonstrate how differences in the dendritic development are visualized and quantitatively assessed. The combination of the presence of an extensive dendritic tree, selective and intense immunostaining methods, organotypic slice cultures which cover the period of dendritic growth and a mouse model with Purkinje cell specific EGFP expression make Purkinje cells a powerful model system for revealing the mechanisms of dendritic development.

We present a protocol that permits to view and to quantitatively asses the morphology of the dendritic tree of individual Purkinje cells grown in organotypic cerebellar slice cultures. This protocol is intended to promote studies on the mechanisms of Purkinje cell dendritic development.

El análisis de la morfología de células dendríticas Purkinje en cultivos de corte organotípicos

Purkinje cells are an attractive model system for studying dendritic development, because they have an impressive dendritic tree which is strictly ...

Lateral Diffusion and Exocytosis of Membrane Proteins in Cultured Neurons Assessed using Fluorescence Recovery and Fluorescence-loss Photobleaching

Membrane proteins such as receptors and ion channels undergo active trafficking in neurons, which are highly polarised and morphologically complex. This directed trafficking is of fundamental importance to deliver, maintain or remove synaptic proteins.
Super-ecliptic pHluorin (SEP) is a pH-sensitive derivative of eGFP that has been extensively used for live cell imaging of plasma membrane proteins1-2. At low pH, protonation of SEP decreases photon absorption and eliminates fluorescence emission. As most intracellular trafficking events occur in compartments with low pH, where SEP fluorescence is eclipsed, the fluorescence signal from SEP-tagged proteins is predominantly from the plasma membrane where the SEP is exposed to a neutral pH extracellular environment. When illuminated at high intensity SEP, like every fluorescent dye, is irreversibly photodamaged (photobleached)3-5. Importantly, because low pH quenches photon absorption, only surface expressed SEP can be photobleached whereas intracellular SEP is unaffected by the high intensity illumination6-10. 
FRAP (fluorescence recovery after photobleaching) of SEP-tagged proteins is a convenient and powerful technique for assessing protein dynamics at the plasma membrane. When fluorescently tagged proteins are photobleached in a region of interest (ROI) the recovery in fluorescence occurs due to the movement of unbleached SEP-tagged proteins into the bleached region. This can occur via lateral diffusion and/or from exocytosis of non-photobleached receptors supplied either by de novo synthesis or recycling (see Fig. 1). The fraction of immobile and mobile protein can be determined and the mobility and kinetics of the diffusible fraction can be interrogated under basal and stimulated conditions such as agonist application or neuronal activation stimuli such as NMDA or KCl application8,10. 
We describe photobleaching techniques designed to selectively visualize the recovery of fluorescence attributable to exocytosis. Briefly, an ROI is photobleached once as with standard FRAP protocols, followed, after a brief recovery, by repetitive bleaching of the flanking regions. This 'FRAP-FLIP' protocol, developed in our lab, has been used to characterize AMPA receptor trafficking at dendritic spines10, and is applicable to a wide range of trafficking studies to evaluate the intracellular trafficking and exocytosis.

This report describes the use of live cell imaging and photobleach techniques to determine the surface expression, transport pathways and trafficking kinetics of exogenously expressed, pH-sensitive GFP-tagged proteins at the plasma membrane of neurons.

Difusión lateral y exocitosis de proteínas de membrana en neuronas cultivadas evaluó a través de la recuperación de fluorescencia y la pérdida de fluorescencia photobleaching

Membrane proteins such as receptors and ion channels undergo active trafficking in neurons, which are highly polarised and morphologically complex. This ...

Organotypic Slice Cultures to Study Oligodendrocyte Dynamics and Myelination

NG2 expressing cells (polydendrocytes, oligodendrocyte precursor cells) are the fourth major glial cell population in the central nervous system. During embryonic and postnatal development they actively proliferate and generate myelinating oligodendrocytes. These cells have commonly been studied in primary dissociated cultures, neuron cocultures, and in fixed tissue. Using newly available transgenic mouse lines slice culture systems can be used to investigate proliferation and differentiation of oligodendrocyte lineage cells in both gray and white matter regions of the forebrain and cerebellum. Slice cultures are prepared from early postnatal mice and are kept in culture for up to 1 month. These slices can be imaged multiple times over the culture period to investigate cellular behavior and interactions. This method allows visualization of NG2 cell division and the steps leading to oligodendrocyte differentiation while enabling detailed analysis of region-dependent NG2 cell and oligodendrocyte functional heterogeneity. This is a powerful technique that can be used to investigate the intrinsic and extrinsic signals influencing these cells over time in a cellular environment that closely resembles that found in vivo.

A technique to study NG2 cells and oligodendrocytes using a slice culture system of the forebrain and cerebellum is described. This method allows examination of the dynamics of proliferation and differentiation of cells within the oligodendrocyte lineage where the extracellular environment can be easily manipulated while maintaining tissue cytoarchitecture.

Culturas Organotípicos Slice para Estudiar Oligodendrocyte Dinámica y mielinización

NG2 expressing cells (polydendrocytes, oligodendrocyte precursor cells) are the fourth major glial cell population in the central nervous system. During ...

The Analysis of Neurovascular Remodeling in Entorhino-hippocampal Organotypic Slice Cultures

Ischemic brain injury is among the most common and devastating conditions compromising proper brain function and often leads to persisting functional deficits in the affected patients. Despite intensive research efforts, there is still no effective treatment option available that reduces neuronal injury and protects neurons in the ischemic areas from delayed secondary death. Research in this area typically involves the use of elaborate and problematic animal models. Entorhino-hippocampal organotypic slice cultures challenged with oxygen and glucose deprivation (OGD) are established in&#160;vitro models which mimic cerebral ischemia. The novel aspect of this study is that changes of the brain blood vessels are studied in addition to neuronal changes and the reaction of both the neuronal compartment and the vascular compartment can be compared and correlated. The methods presented in this protocol substantially broaden the potential applications of the organotypic slice culture approach. The induction of OGD or hypoxia alone can be applied by rather simple means in organotypic slice cultures and leads to reliable and reproducible damage in the neural tissue. This is in stark contrast to the complicated and problematic animal experiments inducing stroke and ischemia in vivo. By broadening the analysis to include the study of the reaction of the vasculature could provide new ways on how to preserve and restore brain functions. The slice culture approach presented here might develop into an attractive and important tool for the study of ischemic brain injury and might be useful for testing potential therapeutic measures aimed at neuroprotection.

A protocol for entorhino-hippocampal organotypic slice cultures, which allows reproducing many aspects of ischemic brain injury, is presented. By studying changes of the neurovasculature in addition to changes in the neurons, this protocol is a versatile tool to study plastic changes in neural tissue after injury.

Ischemic brain injury is among the most common and devastating conditions compromising proper brain function and often leads to persisting functional ...

Investigation of Synaptic Tagging/Capture and Cross-capture using Acute Hippocampal Slices from Rodents

Synaptic tagging and capture (STC) and cross-tagging are two important mechanisms at cellular level that explain how synapse-specificity and associativity is achieved in neurons within a specific time frame. These long-term plasticity-related processes are the leading candidate models to study the basis of memory formation and persistence at the cellular level. Both STC and cross-tagging involve two serial processes: (1) setting of the synaptic tag as triggered by a specific pattern of stimulation, and (2) synaptic capture, whereby the synaptic tag interacts with newly synthesized plasticity-related proteins (PRPs). Much of the understanding about the concepts of STC and cross-tagging arises from the studies done in CA1 region of the hippocampus and because of the technical complexity many of the laboratories are still unable to study these processes. Experimental conditions for the preparation of hippocampal slices and the recording of stable late-LTP/LTD are extremely important to study synaptic tagging/cross-tagging. This video article describes the experimental procedures to study long-term plasticity processes such as STC and cross-tagging in the CA1 pyramidal neurons using stable, long-term field-potential recordings from acute hippocampal slices of rats.

This video article describes experimental procedures to study long-term plasticity and its associative processes such as synaptic tagging, capture and cross-tagging in the CA1 pyramidal neurons using acute hippocampal slices from rodents.

Investigación de sináptica Tagging / Captura y Cruz de captura utilizando aguda hipocampo rebanadas de Roedores

Synaptic tagging and capture (STC) and cross-tagging are two important mechanisms at cellular level that explain how synapse-specificity and associativity ...

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.

Resolución de alta Análisis Cuantitativo Inmunoelectrónica de Receptores de Membrana en la retina cinta sinapsis

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

Organotypic Hippocampal Slice Cultures As a Model to Study Neuroprotection and Invasiveness of Tumor Cells

In organotypic hippocampal slice cultures (OHSC), the morphological and functional characteristics of both neurons and glial cells are well preserved. This model is suitable for addressing different research questions that involve studies on neuroprotection, electrophysiological experiments on neurons, neuronal networks or tumor invasion. The hippocampal architecture and neuronal activity in multisynaptic circuits are well conserved in OHSC, even though the slicing procedure itself initially lesions and leads to formation of a glial scar. The scar formation alters presumably the mechanical properties and diffusive behavior of small molecules, etc. Slices allow the monitoring of time dependent processes after brain injury without animal surgery, and studies on interactions between various brain-derived cell types, namely astrocytes, microglia and neurons under both physiological and pathological conditions. An ambivalent aspect of this model is the absence of blood flow and immune blood cells. During the progression of the neuronal injury, migrating immune cells from the blood play an important role. As those cells are missing in slices, the intrinsic processes in the culture may be observed without external interference. Moreover, in OHSC the composition of the medium-external environment is precisely controlled. A further advantage of this method is the lower number of sacrificed animals compared to standard preparations. Several OHSC can be obtained from one animal making simultaneous studies with multiple treatments in one animal possible. For these reasons, OHSC are well suited to analyze the effects of new protective therapeutics after tissue damage or during tumor invasion. 
The protocol presented here describes a preparation method of OHSC that allows generating highly reproducible, well preserved slices that can be used for a variety of experimental research, like neuroprotection or tumor invasion studies.

Organotypic hippocampal slice cultures (OHSC) represent an in vitro model that simulates the in vivo situation very well. Here we describe a vibratome-based improved slicing protocol to obtain high quality slices for use in assessing the neuroprotective potential of novel substances or the biological behavior of tumor cells.

Culturas de rebanada Hippocampal Organotypic como un modelo para estudio neuroprotección e invasividad de las células tumorales

In organotypic hippocampal slice cultures (OHSC), the morphological and functional characteristics of both neurons and glial cells are well preserved. ...