Questo lavoro è stato finanziato dalla Neuro-Bio Ltd. Vorremmo ringraziare il Dr. Giovanni Ferrati e Dr. Sergio Rotondo (Neuro-Bio) per i loro commenti e consigli sul manoscritto.

Tutti gli studi sugli animali sono stati effettuati nell'ambito di protocolli approvati.
Nota: In questa sezione, la sequenza delle fasi principali eseguite durante la procedura sperimentale e l'intervallo di tempo consigliato è fornito (Figura 1). Inoltre, una descrizione dettagliata del protocollo è completata da un pannello illustrativo, mostrando azioni critiche che vanno dalla rimozione del cervello per omogeneizzazione del tessuto dopo il periodo di incubazione (Figura 2). I dettagli per quanto riguarda i materiali e le istruzioni per costruire l'apparato e la successiva fase per l'analisi di WB sono descritti in precedenza22.
1. chirurgici strumenti, impostazioni Vibratome e preparazione di trattamento
Nota: Eseguire le seguenti operazioni prima di avviare la procedura sperimentale:
<ol><li>Preparare due diversi artificiali liquidi cerebrospinali (aCSFs), uno usato per il taglio del cervello e l'altro per la fase di incubazione come precedentemente descritto29. Brevemente, le concentrazioni di lavoro (in mmol) dei due aCSFs sono per la aCSF "slicing": 120 NaCl, 5 KCl, 20 NaHCO3, 2,4 CaCl2, 2 MgSO4, 1,2 KH2PO4e 10 glucosio; 6.7 HEPES sale e 3,3 HEPES acido; pH: 7.1. Mentre per la "registrazione" aCSF: 124 NaCl, 3,7 KCl, 26 NaHCO3, 2 CaCl2, 1.3 MgSO4, 1,3 KH2PO4e 10 glucosio; pH: 7.1.</li>
	<li>Mescolare bene le soluzioni e poi mettere il ghiaccio e ossigenare il aCSF affettare al fine di avere freddo durante la rimozione del cervello e il sezionamento successive. Tenere a temperatura ambiente (TA) e fornitura di ossigeno per la registrazione aCSF.</li>
	<li>Posizionare gli strumenti sotto il cofano di dissezione per la rimozione di decapitazione e cervello, vale a dire, ghigliottina, kit di dissezione chirurgica (forbici, pinze, lame) e spatola.</li>
	<li>Consente di impostare i parametri del vibratome selezionando lo spessore di taglio (300 µm in questa preparazione) e la frequenza alle 7 e la velocità a 6. Inserire la camera vibratome in suo spazio adeguato e circondano con ghiaccio.</li>
	<li>Aprire la valvola di carbogen (95% O2, 5% CO2) per ossigenare il "taglio" (aCSF) durante il sezionamento del cervello. Selezionare la portata minima, circa 2 mL/min.</li>
	<li>Prendere due tubi di 15 mL per preparare le condizioni per testare. Aggiungere in una provetta 10 mL della "registrazione" aCSF da solo (gruppo di controllo) e in altro, 10 mL della "registrazione" aCSF arricchita con T30 ad una concentrazione di 2 µM (gruppo trattato). Vortice sia tubi e tenerli sul ghiaccio fino al loro utilizzo nella fase di preparazione di installazione (sezione 3).</li>
</ol>2. anestesia, estrazione di cervello e affettare
Nota: In questo studio, 9 P14 tipo selvaggio ratti maschii di Wistar sono stati usati. Estrazione di cervello e affettare successive costituiscono una parte fondamentale del protocollo poiché deve essere eseguite rapidamente (entro 10 min) al fine di prevenire o almeno rallentare i processi di degenerazione del tessuto.
<ol><li>Aggiungere 1,5 mL 100% w/w di isoflurane su uno strato di cotone nella camera di induzione, metti l'animale all'interno e chiudere il coperchio. Attendere fino a quando l'animale è anestetizzato, confermando l'assenza del riflesso del pedale e quindi decapitare l'animale utilizzando la ghigliottina.</li>
	<li>Mantenere la testa dell'animale all'interno di una pentola contenente ghiacciata affettare aCSF durante la fase di rimozione del cervello (Figura 2A -C).</li>
	<li>Incidere la pelle sopra il cranio con una lama chirurgica, poi tagliare il cranio con le forbici seguendo la linea mediana, dalla parte posteriore e procedere anteriormente fino a raggiungere l'osso sopra gli OB (Figura 2A).</li>
	<li>Tirare lateralmente i due lati del cranio usando un paio di pinze per avere accesso al cervello (Figura 2B). Inserire una spatola ventralmente al cervello, delicatamente scoop fuori e tenere che idratata in aCSF ghiacciata "slicing" per circa 5 min (Figura 2).</li>
	<li>Smaltire il cervello su carta da filtro e tagliare fuori il cervelletto usando una lama (Figura 2D). Incollare il cervello verticalmente sul disco vibratome e inserirlo all'interno della camera di taglio, riempirlo con gelida aCSF "affettare" e fornire ossigeno (Figura 2E).</li>
	<li>Regolare l'intervallo di taglio e procedere con il cervello di sezionamento (Figura 2F). Raccogliere le sezioni che contengono la regione di interesse, come il setto mediale (MS), banda diagonale di Broca (DBB) e substantia innominata (SI), come descritto in precedenza22. Dall'alto verso il basso, le tre fette contengono rostrale (R), intermedio (I) e caudale (C) parte del BF (Figura 2).</li>
	<li>Dividere lungo la linea mediana ogni sezione con piccole forbici, ottenendo due speculari hemislices (Figura 2 H), utilizzati singolarmente come il controllo e la condizione trattata presso sullo stesso piano anatomico.</li>
	<li>Mantenere la hemisections nella camera vibratome per 5-10 minuti, quindi trasferirli con una pipetta di vetro in una pentola di bubbling con registrazione aCSF. Conservare a temperatura ambiente per circa 30 minuti per recuperare.</li>
	<li>Riempire, nel frattempo, tre fiale di vetro con 3 mL di registrazione aCSF da solo (precedentemente preparata al punto 1.6 per il gruppo di controllo) e tre fiale con 3 mL di aCSF arricchito con T30 (precedentemente preparata al punto 1.6) per il gruppo trattato.</li>
</ol>3. preparazione di setup
<ol><li>Trasferire la hemisections nei loro corrispondenti flaconi di vetro (Figura 2I) al fine di avere tre hemislices consecutivi (compresa la regione BF rostrale, intermedia e caudale) per il gruppo di controllo (cornice verde, Figura 2J) e loro controparti per il gruppo trattato (cornice rossa, Figura 2J) di corrispondenza.</li>
	<li>Trasferire il tessuto cerebrale con due pennelli diversi, uno per il hemislices di controllo e un altro per le controparti trattate, al fine di evitare qualsiasi contaminazione tra condizioni.</li>
	<li>Ogni flaconcino di vetro con il coperchio corrispondente, che presenta l'ago ossigenante (21G) (Figura 2J) della guarnizione. Collegare il tubo principale dell'apparato all'origine di carbogen (Figura 2 K). Fornire ossigeno ai hemislices per tutto il periodo di incubazione con una portata minima di 2 mL/min per evitare qualsiasi movimento del tessuto cerebrale e possibili danni meccanici durante l'esperimento. Iniziare l'incubazione di 5 h. Eseguire i passaggi 3.1-3.3 entro 5 min. Nota: Controllare frequentemente (ogni 15-20 minuti) se l'ossigeno è fornito in tutte le fiale e che il flusso non si muove il tessuto dal basso.</li>
</ol>4. campione omogeneizzazione
<ol><li>Interrompere il flusso di ossigeno dopo l'incubazione e rimuovere tutti i coperchi dai flaconcini. Trasferire la hemislices, utilizzando i pennelli corretta, in provette da 1,5 mL contenente 250 µ l di tampone di Lisi, mantenere i tubi sul ghiaccio (Figura 2 L). Per rendere il lysis buffer, mescolare PBS 1 x con un cocktail di inibitori di proteasi e fosfatasi sia diluito a 1: 100 e omogeneizzare il tessuto con diversi pestelli per prevenire la contaminazione tra i campioni. Completare queste azioni entro 10-15 min.</li>
	<li>Centrifugare il cervello lisato a 1.000 x g per 5 min a 4 ° C. Trasferire il surnatante in nuovi tubi e mantenere i campioni a-80 ° C.</li>
</ol>5. la lettura della concentrazione nella proteina e analisi Western Blot
<ol><li>Determinare la concentrazione di proteina di ogni campione e successivamente preparare le aliquote per l'analisi Western blot come descritto in precedenza22.</li>
	<li>Effettuare analisi statistiche per valutare gli effetti del trattamento sull'espressione della proteina.</li>
</ol>

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Gli autori dichiarano concorrenti interessi finanziari. Susan A. Greenfield è il fondatore e Presidente di Neuro-Bio Limited, un'azienda privatamente posseduta e detiene azioni della società. Emanuele Brai e Antonella Cogoni sono dipendenti di Neuro-Bio Ltd.

L'aspetto principale di questo protocollo, basato sulla tecnica del cervello ben consolidata ex vivo , permette di testare in modo sincrono due hemislices speculare, ottenuti sullo stesso piano anatomico, controllo della loro risposta dopo l'applicazione di uno specifico condizione (controllare o trattati); Questo offre quindi un paradigma sperimentale sotto stretto controllato quanto possibile. La possibilità di valutare in un tempo - dose- e site-specific modo diverse sostanze neurochimiche legate al deficit ...

Annuncio è che una patologia cronica caratterizzata da danno progressivo neurodegenerative che interessano aree differenti del cervello, come la corteccia di entorhinal (CE), BF, ippocampo (HC) e bulbo olfattivo (OB)1,2,3, 4,5. La fine delle fasi di sviluppo AD portare ad un declino conoscitivo progressivo, rendendo questa malattia la più comune forma di demenza, pari circa al 70% di tutti i casi6. Malgrado vasto tentativo di comprendere le fasi iniziali che causano AD, non esiste attualmente una definita indicazione sperimentale delucidamento li. Inoltre, la teoria più popolare - del "ipotesi amiloide" - è sempre più messa in discussione dal momento che non fornisce un profilo completo nello spiegare pathobiology annuncio, né una destinazione farmaceutica che si è rivelata efficace7,8 ,9.
Una teoria alternativa che sta ricevendo crescente attenzione suggerisce che i meccanismi iniziali che si verificano durante la neurodegenerazione sono correlati a un cluster di un neurone principalmente suscettibile AD3,10,11 , 12 , 13 , 14. questo hub cellulare eterogeneo rientra all'interno i progetti di BF, mesencefalo e del tronco cerebrale, più aree, quali la CE, HC e OB15,16. Nonostante la sua diversità nella morfologia neuronale e sintesi del neurotrasmettitore, questo nucleo di cellule condivide una caratteristica comune nell'esprimere il dolore, che può anche avere una funzione non-enzimatica17,18. Questo ruolo non-classica come un romanzo di segnalazione molecola media il flusso di calcio (Ca2 +) in neuroni che possono subire gli eventi trofici o tossici in relazione di Ca2 + dose, disponibilità e un neurone età17,18 , 19.
Durante la neurodegenerazione, la perdita cellulare osservata potrebbe essere quindi associata a questa funzione non enzimatici17,18,20, che è attribuibile ad un peptide 30mer (T30) spaccato da mal di C-terminale 20. in linea con i risultati precedenti, riportati su coltura cellulare e optical imaging preparazioni di18,21 , abbiamo dimostrato, attraverso un approccio innovativo basato su ex vivo il fettine di cervello di ratto contenente strutture BF, che ha indotto T30 un annuncio-come il profilo22. In particolare, questa nuova metodologia offre uno scenario più fisiologico di coltura cellulare, poiché mantiene molte delle caratteristiche di un tessuto intatto, che vanno da anatomica alla conservazione di circuiti, seppur per una finestra di tempo di ore. Abbiamo applicato questo protocollo per esplorare gli eventi che si svolgono durante le fasi iniziali della neurodegenerazione, monitoraggio della risposta acuta all'atto dell'applicazione T30.
Nonostante il grande corpo di letteratura sull'uso di cervello fette di indagare i meccanismi molecolari implicati nel danno neuronale o neurogenesi23,24, questo protocollo fornisce per la prima volta un più immediato e sensibile leggere rispetto per l'uso comune di organotipiche fette. Tuttavia, come è il caso per organotipiche sezioni del cervello, questa procedura di fetta acuta può essere adottata per diversi scopi, come ad esempio la valutazione di neuroprotective o molecole neurotossiche, scoperta di primarie cambiamenti molecolari che si verificano in un processo specifico, patologie correlate: analisi immunohistochemical e dosaggi farmacologici per il sistema nervoso centrale.

<table>
	<tbody>
		<tr>
			<td>Sodium chloride (NaCl)</td>
			<td>Sigma-Aldrich, Germany</td>
			<td>S7653</td>
			<td>Reagent for aCSF preparation</td>
		</tr>
		<tr>
			<td>Potassium chloride (KCl)</td>
			<td>Sigma-Aldrich, Germany</td>
			<td>P9333</td>
			<td>Reagent for aCSF preparation</td>
		</tr>
		<tr>
			<td>Sodium bicarbonate (NaHCO3)</td>
			<td>Sigma-Aldrich, Germany</td>
			<td>S5761</td>
			<td>Reagent for aCSF preparation</td>
		</tr>
		<tr>
			<td>Magnesium sulphate heptahydrate (MgSO4 (7H2O))</td>
			<td>Sigma-Aldrich, Germany</td>
			<td>63138</td>
			<td>Reagent for aCSF preparation</td>
		</tr>
		<tr>
			<td>Potassium phosphate monobasic (KH2PO4)</td>
			<td>Sigma-Aldrich, Germany</td>
			<td>P5655</td>
			<td>Reagent for aCSF preparation</td>
		</tr>
		<tr>
			<td>Hepes salt</td>
			<td>Sigma-Aldrich, Germany</td>
			<td>H7006</td>
			<td>Reagent for aCSF preparation</td>
		</tr>
		<tr>
			<td>Hepes acid</td>
			<td>Sigma-Aldrich, Germany</td>
			<td>H3375</td>
			<td>Reagent for aCSF preparation</td>
		</tr>
		<tr>
			<td>Glucose</td>
			<td>Sigma-Aldrich, Germany</td>
			<td>G7528</td>
			<td>Reagent for aCSF preparation</td>
		</tr>
		<tr>
			<td>Calcium chloride dehydrate</td>
			<td>Sigma-Aldrich, Germany</td>
			<td>223506</td>
			<td>Reagent for aCSF preparation</td>
		</tr>
		<tr>
			<td>T30 peptide</td>
			<td>Genosphere Biotechnologies, France</td>
			<td></td>
			<td>AChE-derived peptide tested</td>
		</tr>
		<tr>
			<td>Surgical dissecting kit</td>
			<td>World Precision Instruments, USA</td>
			<td>Item #: MOUSEKIT</td>
			<td>Brain removal step</td>
		</tr>
		<tr>
			<td>Surgical blades</td>
			<td>Swann-Morton, UK</td>
			<td>BS 2982</td>
			<td>Brain removal step</td>
		</tr>
		<tr>
			<td>Filter paper</td>
			<td>Fisher Scientific, USA</td>
			<td>11566873</td>
			<td>Brain preparation for slicing</td>
		</tr>
		<tr>
			<td>Glue</td>
			<td></td>
			<td></td>
			<td>Brain preparation for slicing</td>
		</tr>
		<tr>
			<td>Vibratome</td>
			<td>Leica, Germany</td>
			<td>VT1000 S</td>
			<td>Slicing</td>
		</tr>
		<tr>
			<td>Brushes</td>
			<td></td>
			<td></td>
			<td>Tissue handling</td>
		</tr>
		<tr>
			<td>Oxygen canister</td>
			<td></td>
			<td></td>
			<td>Sectioning and incubation phase</td>
		</tr>
		<tr>
			<td>1x Phosphate buffer saline (PBS)</td>
			<td>Fisher Scientific, USA</td>
			<td>BP2438-4</td>
			<td>Homogenization step</td>
		</tr>
		<tr>
			<td>Phosphatase inhibitors</td>
			<td>Fisher Scientific, USA</td>
			<td>1284-1650</td>
			<td>Homogenization step</td>
		</tr>
		<tr>
			<td>Protease inhibitors</td>
			<td>Roche complete PIC, USA</td>
			<td>4693116001</td>
			<td>Homogenization step</td>
		</tr>
		<tr>
			<td>Pestles</td>
			<td>Starlab, UK</td>
			<td>I1415-5390</td>
			<td>Homogenization step</td>
		</tr>
		<tr>
			<td>Microcentrifuge</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Pierce 660 nm Protein Assay</td>
			<td>Thermo Scientific, USA</td>
			<td>22660</td>
			<td>Protein concentration</td>
		</tr>
	</tbody>
</table>

an alternative approach to study primary events in neurodegeneration using ex vivo rat brain slices

Nonostante i numerosi studi che tentano di sviluppare modelli animali affidabile che riflettendo il primario i processi di neurodegenerazione sottostante, molto pochi sono stati ampiamente accettati. Qui, vi proponiamo una nuova procedura adattata dal ben noto ex vivo fetta tecnica del cervello, che offre una più stretta in vivo-come scenario di in vitro i preparativi, per indagare gli eventi precoci innescando la degenerazione delle cellule, come osservato nel morbo di Alzheimer (annuncio). Questa variante è costituita da passi semplici e facilmente riproducibili, che consentono la conservazione della citoarchitettura anatomica della regione del cervello selezionato e la sua funzionalità locali in un ambiente fisiologico. Diverse aree anatomiche possono essere ottenuti dal cervello stesso, offrendo la possibilità di eseguire esperimenti multipli con i trattamenti in questione in un sito - dose- e tempo-dipendente. Limitazioni potenziali che potrebbero influenzare i risultati relazionati a questa metodologia sono legate alla conservazione del tessuto, vale a dire, il mantenimento della sua integrità anatomica durante le operazioni di affettamento e incubazione e lo spessore di sezione, che possono influenzare l'analisi biochimica e immunohistochemical. Questo metodo può essere impiegato per scopi diversi, come esplorare i meccanismi molecolari coinvolti in condizioni fisiologiche o patologiche, screening di farmaci o dosaggi di dose-risposta. Infine, questo protocollo potrebbe anche ridurre il numero di animali impiegati in studi comportamentali. L'applicazione segnalata qui recentemente descritto e testato per la prima volta su ex vivo il fettine di cervello di ratto contenenti proencefalo basale (BF), che è una delle regioni cerebrali colpite principalmente in annuncio. In particolare, è stato dimostrato che la somministrazione di un peptide tossico derivato dal C-terminale dell'acetilcolinesterasi (AChE) potrebbe richiedere un profilo AD-come, innescando, lungo l'asse antero-posteriore del BF, un'espressione differenziale di proteine alterate in annuncio, ad esempio il recettore nicotinico alfa7 (α7-nAChR), fosforilato Tau (p-Tau) e beta amiloide (Aβ).

Il protocollo presentato qui indica che la somministrazione di un peptide tossico, T30, modula in modo sito-dipendente l'espressione di α7-nAChR, p-Tau e Aβ in sezioni contenenti BF (Figura 3A). Il recettore nicotinico Mostra un aumento significativo nella hemislice rostrale-trattati rispetto alla sua controparte di controllo (fetta 1, p = 0.0310) (Figura 3B), mentre la fetta intermedia non rivela alcun cambiamento tra...

Watch this Scientific Journal Video about An Alternative Approach to Study Primary Events in Neurodegeneration Using Ex Vivo Rat Brain Slices at JoVE.com

An Alternative Approach to Study Primary Events in Neurodegeneration Using Ex Vivo Rat Brain Slices

Presentiamo un metodo che può fornire ulteriori approfondimenti i primi eventi sottostante neurodegenerazione e basato sulla tecnica del cervello stabilito ex vivo , unendo i vantaggi degli esperimenti in vivo e in vitro . Inoltre, rappresenta un'opportunità unica per un confronto diretto del gruppo trattata e non trattata sullo stesso piano anatomico.

Un approccio alternativo per studiare eventi primari nella neurodegenerazione utilizzando fettine di cervello di ratto Ex Vivo

Despite&#160;numerous studies that attempt to develop reliable animal models&#160;which reflecting the primary processes underlying neurodegeneration, ...

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Research

JoVE Journal

Neuroscience

An Alternative Approach to Study Primary Events in Neurodegeneration Using Ex Vivo Rat Brain Slices

6.8K Views.  Culham Science Centre. Presentiamo un metodo che può fornire ulteriori approfondimenti i primi eventi sottostante neurodegenerazione e basato sulla tecnica del cervello stabilito ex vivo , unendo i vantaggi degli esperimenti in vivo e in vitro . Inoltre, rappresenta un'opportunità unica per un confronto diretto del gruppo trattata e non trattata sullo stesso piano anatomico.

Video: An Alternative Approach to Study Primary Events in Neurodegeneration Using Ex Vivo Rat Brain Slices

In vivo Laser Axotomy in C. elegans

Neurons communicate with other cells via axons and dendrites, slender membrane extensions that contain pre- or post-synaptic specializations. If a neuron is damaged by injury or disease, it may regenerate. Cell-intrinsic and extrinsic factors influence the ability of a neuron to regenerate and restore function. Recently, the nematode C. elegans has emerged as an excellent model organism to identify genes and signaling pathways that influence the regeneration of neurons1-6. The main way to initiate neuronal regeneration in C. elegans is laser-mediated cutting, or axotomy. During axotomy, a fluorescently-labeled neuronal process is severed using high-energy pulses. Initially, neuronal regeneration in C. elegans was examined using an amplified femtosecond laser5. However, subsequent regeneration studies have shown that a conventional pulsed laser can be used to accurately sever neurons in vivo and elicit a similar regenerative response1,3,7.
We present a protocol for performing in vivo laser axotomy in the worm using a MicroPoint pulsed laser, a turnkey system that is readily available and that has been widely used for targeted cell ablation. We describe aligning the laser, mounting the worms, cutting specific neurons, and assessing subsequent regeneration. The system provides the ability to cut large numbers of neurons in multiple worms during one experiment. Thus, laser axotomy as described herein is an efficient system for initiating and analyzing the process of regeneration.

In vivo Laser Axotomy in C. elegans

A protocol to cut neurons in C. elegans with a MicroPoint pulsed laser is presented. We describe setting up the system, immobilizing worms, and severing labeled neurons. Advantages include a relatively low-cost system and the ability to sever neuronal processes or ablate cells in vivo.

In vivo Laser assotomia in C. elegans

Neurons communicate with other cells via axons and dendrites, slender membrane extensions that contain pre- or post-synaptic specializations. If a neuron ...

Ricerca

Neuroscienze

A Rapid Approach to High-Resolution Fluorescence Imaging in Semi-Thick Brain Slices

A fundamental goal to both basic and clinical neuroscience is to better understand the identities, molecular makeup, and patterns of connectivity that are characteristic to neurons in both normal and diseased brain. Towards this, a great deal of effort has been placed on building high-resolution neuroanatomical maps1-3. With the expansion of molecular genetics and advances in light microscopy has come the ability to query not only neuronal morphologies, but also the molecular and cellular makeup of individual neurons and their associated networks4. Major advances in the ability to mark and manipulate neurons through transgenic and gene targeting technologies in the rodent now allow investigators to 'program' neuronal subsets at will5-6. Arguably, one of the most influential contributions to contemporary neuroscience has been the discovery and cloning of genes encoding fluorescent proteins (FPs) in marine invertebrates7-8, alongside their subsequent engineering to yield an ever-expanding toolbox of vital reporters9. Exploiting cell type-specific promoter activity to drive targeted FP expression in discrete neuronal populations now affords neuroanatomical investigation with genetic precision.
Engineering FP expression in neurons has vastly improved our understanding of brain structure and function. However, imaging individual neurons and their associated networks in deep brain tissues, or in three dimensions, has remained a challenge. Due to high lipid content, nervous tissue is rather opaque and exhibits auto fluorescence. These inherent biophysical properties make it difficult to visualize and image fluorescently labelled neurons at high resolution using standard epifluorescent or confocal microscopy beyond depths of tens of microns. To circumvent this challenge investigators often employ serial thin-section imaging and reconstruction methods10, or 2-photon laser scanning microscopy11. Current drawbacks to these approaches are the associated labor-intensive tissue preparation, or cost-prohibitive instrumentation respectively.
Here, we present a relatively rapid and simple method to visualize fluorescently labelled cells in fixed semi-thick mouse brain slices by optical clearing and imaging. In the attached protocol we describe the methods of: 1) fixing brain tissue in situ via intracardial perfusion, 2) dissection and removal of whole brain, 3) stationary brain embedding in agarose, 4) precision semi-thick slice preparation using new vibratome instrumentation, 5) clearing brain tissue through a glycerol gradient, and 6) mounting on glass slides for light microscopy and z-stack reconstruction (Figure 1).
For preparing brain slices we implemented a relatively new piece of instrumentation called the 'Compresstome' VF-200 (http://www.precisionary.com/products_vf200.html). This instrument is a semi-automated microtome equipped with a motorized advance and blade vibration system with features similar in function to other vibratomes. Unlike other vibratomes, the tissue to be sliced is mounted in an agarose plug within a stainless steel cylinder. The tissue is extruded at desired thicknesses from the cylinder, and cut by the forward advancing vibrating blade. The agarose plug/cylinder system allows for reproducible tissue mounting, alignment, and precision cutting. In our hands, the 'Compresstome' yields high quality tissue slices for electrophysiology, immunohistochemistry, and direct fixed-tissue mounting and imaging. Combined with optical clearing, here we demonstrate the preparation of semi-thick fixed brain slices for high-resolution fluorescent imaging.

Here we describe a rapid and simple method to image fluorescently labeled cells in semi-thick brain slices. By fixing, slicing, and optically clearing brain tissue we describe how standard epifluorescent or confocal imaging can be used to visualize individual cells and neuronal networks within intact nervous tissue.

Un metodo rapido per High-Resolution Imaging di fluorescenza in semi-spessa fettine di cervello

A fundamental goal to both basic and clinical neuroscience is to better understand the identities, molecular makeup, and patterns of connectivity that are ...

GABA-activated Single-channel and Tonic Currents in Rat Brain Slices

The GABAA channels are present in all neurons and are located both at synapses and outside of synapses where they generate phasic and tonic currents, respectively 4,5,6,7 The GABAA channel is a pentameric GABA-gated chloride channel. The channel subunits are grouped into 8 families (&alpha;1-6, &beta;1-3, &gamma;1-3, &delta;, &#949;, &theta;, &pi; and &rho;). Two alphas, two betas and one 3rd subunit form the functional channel 8. By combining studies of sub-type specific GABA-activated single-channel molecules with studies including all populations of GABAA channels in the neuron it becomes possible to understand the basic mechanism of neuronal inhibition and how it is modulated by pharmacological agents.
We use the patch-clamp technique 9,10 to study the functional properties of the GABAA channels in alive neurons in hippocampal brain slices and record the single-channel and whole-cell currents. We further examine how the channels are affected by different GABA concentrations, other drugs and intra and extracellular factors. For detailed theoretical and practical description of the patch-clamp method please see The Single-Channel Recordings edited by B Sakman and E Neher 10.

We use the patch-clamp technique to measure GABA-activated single-channel currents (GABAA channels, GABAA receptors) and the synaptic and tonic currents they generate in neurons. Activation of the channels decreases neuronal excitability in health and disease 1,2,3,4.

Correnti a singolo canale e Tonico GABA-attivati ​​in fettine di cervello di ratto

The GABAA channels are present in all neurons and are located both at synapses and outside of synapses where they generate phasic and tonic currents, ...

Methods for Study of Neuronal Morphogenesis: Ex vivo RNAi Electroporation in Embryonic Murine Cerebral Cortex

The cerebral cortex directs higher cognitive functions. This six layered structure is generated in an inside-first, outside-last manner, in which the first born neurons remain closer to the ventricle while the last born neurons migrate past the first born neurons towards the surface of the brain1. In addition to neuronal migration2, a key process for normal cortical function is the regulation of neuronal morphogenesis3. While neuronal morphogenesis can be studied in vitro in primary cultures, there is much to be learned from how these processes are regulated in tissue environments.
We describe techniques to analyze neuronal migration and/or morphogenesis in organotypic slices of the cerebral cortex4,6. A pSilencer modified vector is used which contains both a U6 promoter that drives the double stranded hairpin RNA and a separate expression cassette that encodes GFP protein driven by a CMV promoter7-9. Our approach allows for the rapid assessment of defects in neurite outgrowth upon specific knockdown of candidate genes and has been successfully used in a screen for regulators of neurite outgrowth8. Because only a subset of cells will express the RNAi constructs, the organotypic slices allow for a mosaic analysis of the potential phenotypes. Moreover, because this analysis is done in a near approximation of the in vivo environment, it provides a low cost and rapid alternative to the generation of transgenic or knockout animals for genes of unknown cortical function. Finally, in comparison with in vivo electroporation technology, the success of ex vivo electroporation experiments is not dependant upon proficient surgery skill development and can be performed with a shorter training time and skill.

Methods for Study of Neuronal Morphogenesis: Ex vivo RNAi Electroporation in Embryonic Murine Cerebral Cortex

To conduct a rapid assessment of the function of genes in the development of cerebral cortex, we describe methods involving the ex vivo electroporation of plasmids co-expressing inhibitory RNA (RNAi) and GFP in murine embryonic cortex. This protocol is amenable to the study of various aspects of neurodevelopment such as neurogenesis, neuronal migration and neuronal morphogenesis including dendrite and axon outgrowth.

Metodi per lo studio della morfogenesi neuronale:<em&gt; Ex vivo</em&gt; Elettroporazione RNAi in Embryonic Cerebral Cortex Murine

The cerebral cortex directs higher cognitive functions. This six layered structure is generated in an inside-first, outside-last manner, in which the ...

Functional Neuroimaging Using Ultrasonic Blood-brain Barrier Disruption and Manganese-enhanced MRI

Although mice are the dominant model system for studying the genetic and molecular underpinnings of neuroscience, functional neuroimaging in mice remains technically challenging. One approach, Activation-Induced Manganese-enhanced MRI (AIM MRI), has been used successfully to map neuronal activity in rodents 1-5. In AIM MRI, Mn2+ acts a calcium analog and accumulates in depolarized neurons 6,7. Because Mn2+ shortens the T1 tissue property, regions of elevated neuronal activity will enhance in MRI. Furthermore, Mn2+ clears slowly from the activated regions; therefore, stimulation can be performed outside the magnet prior to imaging, enabling greater experimental flexibility. However, because Mn2+ does not readily cross the blood-brain barrier (BBB), the need to open the BBB has limited the use of AIM MRI, especially in mice.
One tool for opening the BBB is ultrasound. Though potentially damaging, if ultrasound is administered in combination with gas-filled microbubbles (i.e., ultrasound contrast agents), the acoustic pressure required for BBB opening is considerably lower. This combination of ultrasound and microbubbles can be used to reliably open the BBB without causing tissue damage 8-11.
Here, a method is presented for performing AIM MRI by using microbubbles and ultrasound to open the BBB. After an intravenous injection of perflutren microbubbles, an unfocused pulsed ultrasound beam is applied to the shaved mouse head for 3 minutes. For simplicity, we refer to this technique of BBB Opening with Microbubbles and UltraSound as BOMUS 12. Using BOMUS to open the BBB throughout both cerebral hemispheres, manganese is administered to the whole mouse brain. After experimental stimulation of the lightly sedated mice, AIM MRI is used to map the neuronal response.
To demonstrate this approach, herein BOMUS and AIM MRI are used to map unilateral mechanical stimulation of the vibrissae in lightly sedated mice 13. Because BOMUS can open the BBB throughout both hemispheres, the unstimulated side of the brain is used to control for nonspecific background stimulation. The resultant 3D activation map agrees well with published representations of the vibrissae regions of the barrel field cortex 14. The ultrasonic opening of the BBB is fast, noninvasive, and reversible; and thus this approach is suitable for high-throughput and/or longitudinal studies in awake mice.

A technique is described for broadly opening the blood-brain barrier in the mouse using microbubbles and ultrasound. Using this technique, manganese can be administered to the mouse brain. Because manganese is an MRI contrast agent that accumulates in depolarized neurons, this approach enables imaging of neuronal activity.

Neuroimaging funzionale con l&#39;impiego dell&#39;ecografia emato-encefalica e la barriera di Turbativa del Manganese-enhanced MRI

Although mice are the dominant model system for studying the genetic and molecular underpinnings of neuroscience, functional neuroimaging in mice remains ...

Brain Slice Biotinylation: An Ex Vivo Approach to Measure Region-specific Plasma Membrane Protein Trafficking in Adult Neurons

Regulated endocytic trafficking is the central mechanism facilitating a variety of neuromodulatory events, by dynamically controlling receptor, ion channel, and transporter cell surface presentation on a minutes time scale.&#160;There is a broad diversity of mechanisms that control endocytic trafficking of individual proteins. Studies investigating the molecular underpinnings of trafficking have primarily relied upon surface biotinylation to quantitatively measure changes in membrane protein surface expression in response to exogenous stimuli and gene manipulation.&#160;However, this approach has been mainly limited to cultured cells, which may not faithfully reflect the physiologically relevant mechanisms at play in adult neurons.&#160;Moreover, cultured cell approaches may underestimate region-specific differences in trafficking mechanisms.&#160;Here, we describe an approach that extends cell surface biotinylation to the acute brain slice preparation.&#160;We demonstrate that this method provides a high-fidelity approach to measure rapid changes in membrane protein surface levels in adult neurons.&#160;This approach is likely to have broad utility in the field of neuronal endocytic trafficking.

Brain Slice Biotinylation: An Ex Vivo Approach to Measure Region-specific Plasma Membrane Protein Trafficking in Adult Neurons

Neuronal membrane trafficking dynamically controls plasma membrane protein availability and significantly impacts neurotransmission.&#160;To date, it has been challenging to measure neuronal endocytic trafficking in adult neurons.&#160;Here, we describe a highly effective, quantitative method to measure rapid changes in surface protein expression ex vivo in acute brain slices.

Slice Cervello biotinilazione: An<em&gt; Ex Vivo</em&gt; Approccio alla Misura Regione-specifica proteina Tratta plasma membrana in neuroni adulti

Regulated endocytic trafficking is the central mechanism facilitating a variety of neuromodulatory events, by dynamically controlling receptor, ion ...

Mouse Hindbrain Ex Vivo Culture to Study Facial Branchiomotor Neuron Migration

Embryonic neurons are born in the ventricular zone of the brain, but subsequently migrate to new destinations to reach appropriate targets. Deciphering the molecular signals that cooperatively guide neuronal migration in the embryonic brain is therefore important to understand how the complex neural networks form which later support postnatal life. Facial branchiomotor (FBM) neurons in the mouse embryo hindbrain migrate from rhombomere (r) 4 caudally to form the paired facial nuclei in the r6-derived region of the hindbrain. Here we provide a detailed protocol for wholemount ex vivo culture of mouse embryo hindbrains suitable to investigate the signaling pathways that regulate FBM migration. In this method, hindbrains of E11.5 mouse embryos are dissected and cultured in an open book preparation on cell culture inserts for 24 hr. During this time, FBM neurons migrate caudally towards r6 and can be exposed to function-blocking antibodies and small molecules in the culture media or heparin beads loaded with recombinant proteins to examine roles for signaling pathways implicated in guiding neuronal migration.

Mouse Hindbrain Ex Vivo Culture to Study Facial Branchiomotor Neuron Migration

Embryonic neurons are born in the ventricular zone of the neural tube, but migrate to reach appropriate targets. Facial branchiomotor (FBM) neurons are a useful model to study neuronal migration. This protocol describes the wholemount ex vivo culture of mouse embryo hindbrains to investigate mechanisms that regulate FBM migration.

Topo romboencefalo<em&gt; Ex Vivo</em&gt; Cultura per studiare la migrazione Branchiomotor Neuron viso

Embryonic neurons are born in the ventricular zone of the brain, but subsequently migrate to new destinations to reach appropriate targets. Deciphering ...

An Ex Vivo Laser-induced Spinal Cord Injury Model to Assess Mechanisms of Axonal Degeneration in Real-time

Injured CNS axons fail to regenerate and often retract away from the injury site. Axons spared from the initial injury may later undergo secondary axonal degeneration. Lack of growth cone formation, regeneration, and loss of additional myelinated axonal projections within the spinal cord greatly limits neurological recovery following injury. To assess how central myelinated axons of the spinal cord respond to injury, we developed an ex vivo living spinal cord model utilizing transgenic mice that express yellow fluorescent protein in axons and a focal and highly reproducible laser-induced spinal cord injury to document the fate of axons and myelin (lipophilic fluorescent dye Nile Red) over time using two-photon excitation time-lapse microscopy. Dynamic processes such as acute axonal injury, axonal retraction, and myelin degeneration are best studied in real-time. However, the non-focal nature of contusion-based injuries and movement artifacts encountered during in vivo spinal cord imaging make differentiating primary and secondary axonal injury responses using high resolution microscopy challenging. The ex vivo spinal cord model described here mimics several aspects of clinically relevant contusion/compression-induced axonal pathologies including axonal swelling, spheroid formation, axonal transection, and peri-axonal swelling providing a useful model to study these dynamic processes in real-time. Major advantages of this model are excellent spatiotemporal resolution that allows differentiation between the primary insult that directly injures axons and secondary injury mechanisms; controlled infusion of reagents directly to the perfusate bathing the cord; precise alterations of the environmental milieu (e.g., calcium, sodium ions, known contributors to axonal injury, but near impossible to manipulate in vivo); and murine models also offer an advantage as they provide an opportunity to visualize and manipulate genetically identified cell populations and subcellular structures. Here, we describe how to isolate and image the living spinal cord from mice to capture dynamics of acute axonal injury.

An Ex Vivo Laser-induced Spinal Cord Injury Model to Assess Mechanisms of Axonal Degeneration in Real-time

We present a protocol utilizing two-photon excitation time-lapse microscopy to simultaneously visualize the dynamics of axon and myelin injuries in real time. This proposed protocol permits studies of both intrinsic and extrinsic factors which can influence central myelinated axon fate after injury and contribute to permanent clinical disability.

Un<em&gt; Ex Vivo</em&gt; Laser-indotta Spinal Cord Injury modello per valutare i meccanismi di degenerazione assonale in tempo reale

Injured CNS axons fail to regenerate and often retract away from the injury site. Axons spared from the initial injury may later undergo secondary axonal ...

Ex Vivo Optogenetic Dissection of Fear Circuits in Brain Slices

Optogenetic approaches are now widely used to study the function of neural populations and circuits by combining targeted expression of light-activated proteins and subsequent manipulation of neural activity by light. Channelrhodopsins (ChRs) are light-gated cation-channels and when fused to a fluorescent protein their expression allows for visualization and concurrent activation of specific cell types and their axonal projections in defined areas of the brain. Via stereotactic injection of viral vectors, ChR fusion proteins can be constitutively or conditionally expressed in specific cells of a defined brain region, and their axonal projections can subsequently be studied anatomically and functionally via ex vivo optogenetic activation in brain slices. This is of particular importance when aiming to understand synaptic properties of connections that could not be addressed with conventional electrical stimulation approaches, or in identifying novel afferent and efferent connectivity that was previously poorly understood. Here, a few examples illustrate how this technique can be applied to investigate these questions to elucidating fear-related circuits in the amygdala. The amygdala is a key region for acquisition and expression of fear, and storage of fear and emotional memories. Many lines of evidence suggest that the medial prefrontal cortex (mPFC) participates in different aspects of fear acquisition and extinction, but its precise connectivity with the amygdala is just starting to be understood. First, it is shown how ex vivo optogenetic activation can be used to study aspects of synaptic communication between mPFC afferents and target cells in the basolateral amygdala (BLA). Furthermore, it is illustrated how this ex vivo optogenetic approach can be applied to assess novel connectivity patterns using a group of GABAergic neurons in the amygdala, the paracapsular intercalated cell cluster (mpITC), as an example.

Ex Vivo Optogenetic Dissection of Fear Circuits in Brain Slices

Optogenetic approaches are widely used to manipulate neural activity and assess the consequences for brain function. Here, a technique is outlined that&#160;upon in vivo expression of the optical activator Channelrhodopsin, allows for ex vivo analysis of synaptic properties of specific long range and local neural connections in fear-related circuits.

Ex Vivo optogenetic dissezione di circuiti paura nel cervello fette

Optogenetic approaches are now widely used to study the function of neural populations and circuits by combining targeted expression of light-activated ...

In Vivo Functional Brain Imaging Approach Based on Bioluminescent Calcium Indicator GFP-aequorin

Functional in vivo imaging has become a powerful approach to study the function and physiology of brain cells and structures of interest. Recently a new method of Ca2+-imaging using the bioluminescent reporter GFP-aequorin (GA) has been developed. This new technique relies on the fusion of the GFP and aequorin genes, producing a molecule capable of binding calcium and&#160;&#8212; with the addition of its cofactor coelenterazine &#8212; emitting bright light that can be monitored through a photon collector. Transgenic lines carrying the GFP-aequorin gene have been generated for both mice and Drosophila. In Drosophila, the GFP-aequorin gene has been placed under the control of the GAL4/UAS binary expression system allowing for targeted expression and imaging within the brain. This method has subsequently been shown to be capable of detecting both inward Ca2+-transients and Ca2+-released from inner stores. Most importantly it allows for a greater duration in continuous recording, imaging at greater depths within the brain, and recording at high temporal resolutions (up to 8.3 msec). Here we present the basic method for using bioluminescent imaging to record and analyze Ca2+-activity within the mushroom bodies, a structure central to learning and memory in the fly brain.

In Vivo Functional Brain Imaging Approach Based on Bioluminescent Calcium Indicator GFP-aequorin

Here we present a novel Ca2+-imaging approach using a bioluminescent reporter. This approach uses a fused construct GFP-aequorin which binds to Ca2+ and emits light, eliminating the need for light excitation. Significantly this method permits long continuous imaging, access to deep brain structures and high temporal resolution.

In Vivo cervello Imaging funzionale approccio basato sul calcio bioluminescente Indicatore GFP-equorina

Functional in vivo imaging has become a powerful approach to study the function and physiology of brain cells and structures of interest. Recently a new ...