Vorremmo riconoscere Drs. Ping Zhu e Susumu Koyama per la loro assistenza durante la configurazione iniziale della tecnica, e il Dr. Veronica Alvarez per l&#39;assistenza nella formattazione del manoscritto. Questo studio è stato finanziato dalla Divisione di Intramurale Ricerca Clinica e Biomedica del NIAAA.

<ol>
	<li>Zhu, P. J., Lovinger, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ethanol+potentiates+gabaergic+synaptic+transmission+in+a+postsynaptic+neuron/synaptic+bouton+preparation+from+basolateral+amygdala.">Ethanol potentiates gabaergic synaptic transmission in a postsynaptic neuron/synaptic bouton preparation from basolateral amygdala.</a> J Neurophysiol. 96, 433-441 (2006).</li><li>Zhu, P. J., Lovinger, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Retrograde+endocannabinoid+signaling+in+a+postsynaptic+neuron/synaptic+bouton+preparation+from+basolateral+amygdala.">Retrograde endocannabinoid signaling in a postsynaptic neuron/synaptic bouton preparation from basolateral amygdala.</a> J Neurosci. 25, 6199-6207 (2005).</li><li>Akaike, N., Moorhouse, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Techniques:+Applications+of+the+nerve-bouton+preparation+in+neuropharmacology.">Techniques: Applications of the nerve-bouton preparation in neuropharmacology.</a> Trends Pharmacol Sci. 24, 44-47 (2003).</li><li>Akaike, N., Murakami, N., Katsurabayashi, S., Jin, Y. H., Imazawa, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Focal+stimulation+of+single+gabaergic+presynaptic+boutons+on+the+rat+hippocampal+neuron.">Focal stimulation of single gabaergic presynaptic boutons on the rat hippocampal neuron.</a> Neurosci Res. 42, 187-195 (2002).</li><li>Ye, J. H., Wang, F., Krnjevic, K., Wang, W., Xiong, Z. G., Zhang, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Presynaptic+glycine+receptors+on+gabaergic+terminals+facilitate+discharge+of+dopaminergic+neurons+in+ventral+tegmental+area.">Presynaptic glycine receptors on gabaergic terminals facilitate discharge of dopaminergic neurons in ventral tegmental area.</a> J Neurosci. 24, 8961-8974 (2004).</li><li>Koyama, S., Matsumoto, N., Kubo, C., Akaike, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Presynaptic+5-ht3+receptor-mediated+modulation+of+synaptic+gaba+release+in+the+mechanically+dissociated+rat+amygdala+neurons.">Presynaptic 5-ht3 receptor-mediated modulation of synaptic gaba release in the mechanically dissociated rat amygdala neurons.</a> J Physiol. 529, 373-383 (2000).</li><li>Deng, C., Li, K. Y., Zhou, C., Ye, J. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ethanol+enhances+glutamate+transmission+by+retrograde+dopamine+signaling+in+a+postsynaptic+neuron/synaptic+bouton+preparation+from+the+ventral+tegmental+area.">Ethanol enhances glutamate transmission by retrograde dopamine signaling in a postsynaptic neuron/synaptic bouton preparation from the ventral tegmental area.</a> Neuropsychopharmacology. 34, 1233-1244 (2009).</li><li>Murakami, N., Ishibashi, H., Katsurabayashi, S., Akaike, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Calcium+channel+subtypes+on+single+gabaergic+presynaptic+terminal+projecting+to+rat+hippocampal+neurons.">Calcium channel subtypes on single gabaergic presynaptic terminal projecting to rat hippocampal neurons.</a> Brain Res. 951, 121-129 (2002).</li><li>Zhu, P. J., Lovinger, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Persistent+synaptic+activity+produces+long-lasting+enhancement+of+endocannabinoid+modulation+and+alters+long-term+synaptic+plasticity.">Persistent synaptic activity produces long-lasting enhancement of endocannabinoid modulation and alters long-term synaptic plasticity.</a> J Neurophysiol. 97, 4386-4389 (2007).</li><li>Inada, H., Maejima, T., Nakahata, Y., Yamaguchi, J., Nabekura, J., Ishibashi, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Endocannabinoids+contribute+to+metabotropic+glutamate+receptor-mediated+inhibition+of+gaba+release+onto+hippocampal+ca3+pyramidal+neurons+in+an+isolated+neuron/bouton+preparation.">Endocannabinoids contribute to metabotropic glutamate receptor-mediated inhibition of gaba release onto hippocampal ca3 pyramidal neurons in an isolated neuron/bouton preparation.</a> Neuroscience. 165, 1377-1389 (2010).</li><li>Miesenbock, G., De Angelis, D. A., Rothman, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Visualizing+secretion+and+synaptic+transmission+with+ph-sensitive+green+fluorescent+proteins.">Visualizing secretion and synaptic transmission with ph-sensitive green fluorescent proteins.</a> Nature. 394, 192-195 (1998).</li><li>Li, Z., Burrone, J., Tyler, W. J., Hartman, K. N., Albeanu, D. F., Murthy, V. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synaptic+vesicle+recycling+studied+in+transgenic+mice+expressing+synaptophluorin.">Synaptic vesicle recycling studied in transgenic mice expressing synaptophluorin.</a> Proc Natl Acad Sci U S A. 102, 6131-6136 (2005).</li></ol>

Nessun conflitto di interessi dichiarati.

Vibrodissociation di successo richiede che le fette contengono neuroni sani e che gli spazi interstiziali sono sufficientemente flessibili da consentire neuroni per uscire dalla fetta senza danni tossici. Così, la tecnica funziona in modo ottimale alle prime età post-natale (P1-21), quando fette sano può essere fatto con materiali meno gliali / interstiatial che si trova a fette cervello adulto. Nella nostra esperienza, tuttavia, ottimizzando la preparazione fetta per la sopravvivenza neuronale nella fetta stesso può essere controproducente per la tecnica vibrodissociation. Mentre noi abitualmente preparare fette di registrazione in situ utilizzando freddo aCSF modificata, in cui saccarosio è stato sostituito per gran parte della Na + extracellulare e Ca 2 +, fette preparato per vibrodissociation possono essere preparati (per esempio taglio) nel nostro aCSF registrazione normale. Nel preparare fette per la registrazione da singoli neuroni nelle stesse fette abbiamo anche posto le fette in aCSF normale a 35 ° C subito dopo il sezionamento e lasciarli per 30-60 minuti a questa temperatura prima di tornare a temperatura ambiente. Tuttavia, fette preparato per vibrodissociation vengono spostati immediatamente a temperatura ambiente subito dopo taglio. Queste procedure forniscono un rendimento più elevato di neuroni sani dopo vibrodissociation, forse a causa della mancanza del tessuto interstiziale ditta che permette ai neuroni di essere più facilmente scosso allentato dalla stessa fetta. Non abbiamo modo esaustivo esame delle condizioni di preparazione fetta, come di routine ottenere neuroni sufficienti per la nostra registrazione ed esperimenti di imaging in un dato giorno. E &#39;possibile che ulteriori modifiche, come i cambiamenti nello spessore fetta o procedure preincubaton, potrebbe essere fatto per aumentare la produzione di neuroni sani. Trattamenti proteasi molto mite sono state provate in uno sforzo per aumentare la resa delle cellule e ottenere la tecnica di lavorare in animali anziani. Tuttavia, immancabilmente anche il trattamento della proteasi mite sembra disturbare la funzione sinapsi. Così, mentre la combinazione di proteasi e di dissociazione meccanica possono ancora essere trovati al lavoro non si è dimostrato affidabile in neuroni proencefalo fino ad oggi. Va inoltre notato il rendimento relativamente basso di neuroni sani dopo vibrodissociation significa che la tecnica è soprattutto utile per lo studio abbondante sottotipi neuronali, soprattutto i neuroni di proiezione. La disponibilità di GFP-esprimere i topi in cui le piccole sottopopolazioni neuronali possono essere facilmente identificate aumenta la possibilità di studiare questi neuroni più rari. Tuttavia, a meno resa neuronale può essere migliorata notevolmente l&#39;accumulo di dati su questi neuroni è probabile che sia relativamente lento. Varie fasi hanno dimostrato di essere decisivo per il caricamento di successo di neuroni con il calcio-sensing coloranti. L&#39;esposizione a AM-esterificati tintura viene eseguita a 37 ° C, e abbiamo avuto successo nel tentativo di tintura di carico a basse temperature. La concentrazione dei coloranti devono essere ottimizzati in termini di tempo di carico e la temperatura in quanto sembra che più alta concentrazione di colorante di caricamento abbassa la concentrazione di calcio nel boutons presinaptico. Abbiamo osservato che a concentrazioni più elevate di carico diminuisce la frequenza e l&#39;ampiezza delle sIPSCs. Quando si carica sensibile al calcio, coloranti in terminali presinaptici di neuroni vibrodissociated, bisogna fare attenzione perché la capacità tampone del boutons piccolo presinaptico può essere diverso nel soma e le dimensioni dei boutons non sono coerenti. Neuron contenenti i piatti vengono lavati con HEPES-buffered soluzione esterna seguente colorante di caricamento e il tempo di recupero dopo il lavaggio è cruciale. Inoltre, per fare una buona tenuta per tutta la registrazione da cellula, le cellule devono essere accuratamente lavati per sbarazzarsi di molecole di colorante non interiorizzato dalla membrana cellulare esterna. Oltre a utilizzare i neuroni vibrodissociated per l&#39;imaging cellulare elettrofisiologia e di vivere, tecniche immunocitochimiche può essere applicato anche a queste cellule 11,12. Le celle possono essere facilmente fissate e colorate con una varietà di anticorpi, e marcatori cellulari di altri. L&#39;utilizzo di queste cellule fornisce una preparazione pulita per la visualizzazione di espressione della proteina in GABAergico terminali presinaptici. Utilizzando topi che esprimono proteine ​​fluorescenti sotto il controllo di promotori specifici per i neuroni GABAergici consente al ricercatore di identificare i singoli terminali sinaptici nella preparazione vibrodissociated (Figura 1). Marcatori fluorescenti immagini di questo tipo può consentire misurazioni morfologiche nei terminali utilizzando laser a base di microscopia e più recenti tecniche come STED (Emission Microscopy stimolazione Depletion). Visualizzazione con coloranti che riportano ciclismo delle vescicole sinaptiche è possibile anche con questa preparazione. Akaike e collaboratori hanno etichettato terminali GABAergici con il colorante styryl, FM1-43 per visualizzare i terminali nelle cellule viventi 4. Dovrebbe anche essere possibile effettuare cella singola transcriptasi inversa PCR per profilo di espressione di RNA in vibrodissociatedneuroni. Questa tecnica è utilizzata abitualmente per enzimaticamente dissociati neuroni e neuroni cresciuti in coltura cellulare.

<table border="1"><tbody><tr><td> Voce </td><td> Azienda </td><td> Catalogo </td><td> Commenti </td></tr><tr><td> Vibrante Slicer Tissue </td><td> Leica Microsystems Inc. </td><td> VT1200S </td><td></td></tr><tr><td> Cellule Dish Cultura (35 mm) </td><td> BD Falcon </td><td> 353001 </td><td></td></tr><tr><td> Fondo di Vetro Piatti </td><td> Willco-piatto </td><td> GWSB-5040 Oppure GWSB-3522 </td><td> 0,16-0,19 vetro mm di spessore per l&#39;imaging </td></tr><tr><td> Manipolatore piezoelettrico </td><td> EXFO-Burleigh </td><td> LSS-3000 </td><td> Potrebbe anche usare relè, ecc </td></tr><tr><td> SD9 Piazza impulsi dello stimolatore </td><td> Grass Technologies </td><td> SD9K </td><td> Per l&#39;attivazione manipolatore piezoelettrico </td></tr><tr><td> Dissezione stereoscopio </td><td> Selvatico Heerbrugg </td><td> TYP 374590 </td><td> Anche usare un&#39;altra stereoscopio </td></tr><tr><td> Flaming / Brown micropipetta estrattore </td><td> Sutter strumento </td><td> P-97 </td><td></td></tr><tr><td> Sottile parete di vetro Capillari </td><td> Mondo Strumenti di precisione </td><td> TW-150F-4 </td><td> Per la fiamma micropipetta di vetro sigillato e patch micropipetta </td></tr><tr><td> Sei Canale perfusione Valve Control Systems </td><td> Warner Instruments </td><td> VC-6 o VC-6M </td><td></td></tr><tr><td> Perfusione Fast-Passo </td><td> Warner Instruments </td><td> SF-77B </td><td></td></tr><tr><td> Microscopio invertito con obiettivi 20-63x </td><td> Nikon </td><td> TS200 Diaphot </td><td></td></tr><tr><td> EMCCD Camera </td><td> ANDOR Tecnologia </td><td> ixon EM + DU-888 </td><td></td></tr><tr><td> Eccitare fluorescenza illuminazione Light Source </td><td> EXFO Photonics Solutions Inc. </td><td> X-Cite 120PC </td><td></td></tr><tr><td> Fluo-4, AM indicatore di calcio </td><td> Molecular Probes </td><td> F14201 </td><td></td></tr></tbody></table>

vibrodissociation of neurons from rodent brain slices to study synaptic transmission and image presynaptic terminals

Meccanica dissociazione dei neuroni del sistema nervoso centrale ha il vantaggio che boutons presinaptica rimangono attaccati al neurone isolato di interesse. Questo consente per l&#39;esame della trasmissione sinaptica in condizioni in cui gli ambienti extracellulare ed intracellulare postsinaptici possono essere ben controllate. Una vibrazione a base di tecnica senza l&#39;uso di proteasi, noto come vibrodissociation, è la tecnica più diffusa per l&#39;isolamento meccanico. Una micropipetta, con la punta fuoco lucidato alla forma di una pallina, viene inserito in una fetta del cervello fatto da un P1-P21 roditori. La micropipetta è vibrato parallela alla superficie fetta e abbassare lo spessore della fetta con conseguente liberazione di neuroni isolati. I neuroni isolati sono pronti per lo studio in pochi minuti di vibrodissociation. Questa tecnica ha dei vantaggi rispetto all&#39;uso di colture primarie neuronali, fettine di cervello e neuroni isolati enzimaticamente tra cui: la produzione rapida di vitale, neuroni relativamente matura adatto per studi elettrofisiologici e di imaging, controllo superiore dell&#39;ambiente extracellulare libero dall&#39;influenza delle cellule vicine; idoneità per esperimenti farmacologici ben controllati con l&#39;applicazione rapida di droga e superfusione cellulare totale e migliorato lo spazio-clamp nelle registrazioni relativi ai neuroni in fetta o preparati colture cellulari a cellula intera. Questa preparazione può essere utilizzato per esaminare sinaptica fisiologia, farmacologia, la modulazione e la plasticità. Imaging in tempo reale di entrambi gli elementi pre-e post-sinaptici nelle cellule viventi e boutons è possibile anche utilizzando i neuroni vibrodissociated. Caratterizzazione dei costituenti molecolari degli elementi pre-e post-sinaptici può essere ottenuta anche con approcci immunologici e di imaging-based.

Watch this Scientific Journal Video about Vibrodissociation of Neurons from Rodent Brain Slices to Study Synaptic Transmission and Image Presynaptic Terminals at JoVE.com

Vibrodissociation of Neurons from Rodent Brain Slices to Study Synaptic Transmission and Image Presynaptic Terminals

Questa relazione dimostra una tecnica per isolamento meccanico di singoli neuroni vitali mantenendo attaccato boutons presinaptica. Vibrodissociated neuroni hanno il vantaggio di una produzione rapida, eccellente controllo farmacologico e migliorato lo spazio-clamp senza influenza dalle cellule vicine. Questo metodo può essere utilizzato per l&#39;imaging di elementi sinaptica e di patch-clamp registrazione.

Vibrodissociation di neuroni da fettine di cervello di roditore studio di trasmissione sinaptica e Immagine terminali presinaptici

Mechanical dissociation of neurons from the central nervous system has the advantage that presynaptic boutons remain attached to the isolated neuron of ...

vibrodissociation-neurons-from-rodent-brain-slices-to-study-synaptic

Research

JoVE Journal

Neuroscience

15.4K Views.  National Institutes of Health/National Institute on Alcohol Abuse and Alcoholism. Questa relazione dimostra una tecnica per isolamento meccanico di singoli neuroni vitali mantenendo attaccato boutons presinaptica. Vibrodissociated neuroni hanno il vantaggio di una produzione rapida, eccellente controllo farmacologico e migliorato lo spazio-clamp senza influenza dalle cellule vicine. Questo metodo può essere utilizzato per l'imaging di elementi sinaptica e di patch-clamp registrazione.

Video: Vibrodissociation of Neurons from Rodent Brain Slices to Study Synaptic Transmission and Image Presynaptic Terminals

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.

Preparazione di oligomeriche β-amiloide 1-42 E induzione di Impairment plasticità sinaptica in fettine di ippocampo

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

Ricerca

Neuroscienze

DiOLISTIC Labeling of Neurons from Rodent and Non-human Primate Brain Slices

DiOLISTIC staining uses the gene gun to introduce fluorescent dyes, such as DiI, into neurons of brain slices (Gan et al., 2009; O'Brien and Lummis, 2007; Gan et al., 2000). Here we provide a detailed description of each step required together with exemplary images of good and bad outcomes that will help when setting up the technique. In our experience, a few steps proved critical for the successful application of DiOLISTICS. These considerations include the quality of the DiI-coated bullets, the extent of fixative exposure, and the concentration of detergent used in the incubation solutions. Tips and solutions for common problems are provided. This is a versatile labeling technique that can be applied to multiple animal species at a wide range of ages. Unlike other fluorescent labeling techniques that are limited to preparations from young animals or restricted to mice because they rely on the expression of a fluorescent transgene, DiOLISTIC labeling can be applied to animals of all ages, species and genotypes and it can be used in combination with immunostaining to identify a specific subpopulation of cells. Here we demonstrate the use of DiOLISTICS to label neurons in brain slices from adult mice and adult non-human primates with the purpose of quantifying dendrite branching and dendritic spine morphology.

We demonstrate the use of the gene gun to introduce fluorescent dyes, such as DiI, into neurons in brain slices from rodents and non-human primates of different ages. In this particular case, we use adult mice (3-6 months old) and adult cynomologus monkeys (9-15 years old). This technique, originally described by the laboratory of Dr. Lichtman (Gan et al., 2000), is well suited for the study of dendritic branching and dendritic spine morphology and can be combined with traditional immunostaining, if detergents are kept at a low concentration.

Etichettatura DiOLISTIC di neuroni da roditori e non-umano Fette cervello dei primati

DiOLISTIC staining uses the gene gun to introduce fluorescent dyes, such as DiI, into neurons of brain slices (Gan et al., 2009; O'Brien and Lummis, 2007; ...

Presynaptic Dopamine Dynamics in Striatal Brain Slices with Fast-scan Cyclic Voltammetry

Extensive research has focused on the neurotransmitter dopamine because of its importance in the mechanism of action of drugs of abuse (e.g. cocaine and amphetamine), the role it plays in psychiatric illnesses (e.g. schizophrenia and Attention Deficit Hyperactivity Disorder), and its involvement in degenerative disorders like Parkinson's and Huntington's disease. Under normal physiological conditions, dopamine is known to regulate locomotor activity, cognition, learning, emotional affect, and neuroendocrine hormone secretion. One of the largest densities of dopamine neurons is within the striatum, which can be divided in two distinct neuroanatomical regions known as the nucleus accumbens and the caudate-putamen. The objective is to illustrate a general protocol for slice fast-scan cyclic voltammetry (FSCV) within the mouse striatum. FSCV is a well-defined electrochemical technique providing the opportunity to measure dopamine release and uptake in real time in discrete brain regions. Carbon fiber microelectrodes (diameter of ~ 7 &mu;m) are used in FSCV to detect dopamine oxidation. The analytical advantage of using FSCV to detect dopamine is its enhanced temporal resolution of 100 milliseconds and spatial resolution of less than ten microns, providing complementary information to in vivo microdialysis.

Using fast-scan cyclic voltammetry to measure electrically evoked presynaptic dopamine dynamics in striatal brain slices.

Dinamica dopamina presinaptica in fettine di cervello striatale con Fast-scan Voltammetria ciclica

Extensive research has focused on the neurotransmitter dopamine because of its importance in the mechanism of action of drugs of abuse (e.g. cocaine and ...

Voltage-sensitive Dye Recording from Axons, Dendrites and Dendritic Spines of Individual Neurons in Brain Slices

Understanding the biophysical properties and functional organization of single neurons and how they process information is fundamental for understanding how the brain works. The primary function of any nerve cell is to process electrical signals, usually from multiple sources. Electrical properties of neuronal processes are extraordinarily complex, dynamic, and, in the general case, impossible to predict in the absence of detailed measurements. To obtain such a measurement one would, ideally, like to be able to monitor, at multiple sites, subthreshold events as they travel from the sites of origin on neuronal processes and summate at particular locations to influence action potential initiation. This goal has not been achieved in any neuron due to technical limitations of measurements that employ electrodes. To overcome this drawback, it is highly desirable to complement the patch-electrode approach with imaging techniques that permit extensive parallel recordings from all parts of a neuron. Here, we describe such a technique - optical recording of membrane potential transients with organic voltage-sensitive dyes (Vm-imaging) - characterized by sub-millisecond and sub-micrometer resolution. Our method is based on pioneering work on voltage-sensitive molecular probes 2. Many aspects of the initial technology have been continuously improved over several decades 3, 5, 11. Additionally, previous work documented two essential characteristics of Vm-imaging. Firstly, fluorescence signals are linearly proportional to membrane potential over the entire physiological range (-100 mV to +100 mV; 10, 14, 16). Secondly, loading neurons with the voltage-sensitive dye used here (JPW 3028) does not have detectable pharmacological effects. The recorded broadening of the spike during dye loading is completely reversible 4, 7. Additionally, experimental evidence shows that it is possible to obtain a significant number (up to hundreds) of recordings prior to any detectable phototoxic effects 4, 6, 12, 13. At present, we take advantage of the superb brightness and stability of a laser light source at near-optimal wavelength to maximize the sensitivity of the Vm-imaging technique. The current sensitivity permits multiple site optical recordings of Vm transients from all parts of a neuron, including axons and axon collaterals, terminal dendritic branches, and individual dendritic spines. The acquired information on signal interactions can be analyzed quantitatively as well as directly visualized in the form of a movie.

An imaging technique for monitoring of membrane potential changes with sub-micrometer spatial and sub-millisecond temporal resolution is described. The technique, based on laser excitation of voltage-sensitive dyes, allows measurements of signals in axons and axon collaterals, terminal dendritic branches, and individual dendritic spines.

Tensione sensibile registrazione Dye da assoni, dendriti e spine dendritiche dei singoli neuroni in fettine di cervello

Understanding the biophysical properties and functional organization of single neurons and how they process information is fundamental for understanding ...

Acute Dissociation of Lamprey Reticulospinal Axons to Enable Recording from the Release Face Membrane of Individual Functional Presynaptic Terminals

Synaptic transmission is an extremely rapid process. Action potential driven influx of Ca2+&#160;into the presynaptic terminal, through voltage-gated calcium channels (VGCCs) located in the release face membrane, is the trigger for vesicle fusion and neurotransmitter release. Crucial to the rapidity of synaptic transmission is the spatial and temporal synchrony between the arrival of the action potential, VGCCs and the neurotransmitter release machinery. The ability to directly record Ca2+&#160;currents from the release face membrane of individual presynaptic terminals is imperative for a precise understanding of the relationship between presynaptic Ca2+&#160;and neurotransmitter release. Access to the presynaptic release face membrane for electrophysiological recording is not available in most preparations and presynaptic Ca2+&#160;entry has been characterized using imaging techniques and macroscopic current measurements &#8211; techniques that do not have sufficient temporal resolution to visualize Ca2+ entry. The characterization of VGCCs directly at single presynaptic terminals has not been possible in central synapses and has thus far been successfully achieved only in the calyx-type synapse of the chick ciliary ganglion and in rat calyces. We have successfully addressed this problem in the giant reticulospinal synapse of the lamprey spinal cord by developing an acutely dissociated preparation of the spinal cord that yields isolated reticulospinal axons with functional presynaptic terminals devoid of postsynaptic structures. We can fluorescently label and identify individual presynaptic terminals and target them for recording. Using this preparation, we have characterized VGCCs directly at the release face of individual presynaptic terminals using immunohistochemistry and electrophysiology approaches. Ca2+ currents have been recorded directly at the release face membrane of individual presynaptic terminals, the first such recording to be carried out at central synapses.

Recording Ca2+ currents at the presynaptic release face membrane is key to a precise understanding of Ca2+ entry and neurotransmitter release. We present an acute dissociation of the lamprey spinal cord that yields functional isolated reticulospinal axons, permitting recording directly from the release face membrane of individual presynaptic terminals.

Acuta dissociazione di Lamprey reticulospinal assoni per attivare la registrazione dal rilascio Volto membrana di singoli funzionali terminali presinaptici

Synaptic transmission is an extremely rapid process. Action potential driven influx of Ca2+&#160;into the presynaptic terminal, through voltage-gated ...

Isolation, Culture and Long-Term Maintenance of Primary Mesencephalic Dopaminergic Neurons From Embryonic Rodent Brains

Degeneration of mesencephalic dopaminergic (mesDA) neurons is the pathological hallmark of Parkinson&#8217;s diseae. Study of the biological processes involved in physiological functions and vulnerability and death of these neurons is imparative to understanding the underlying causes and unraveling the cure for this common neurodegenerative disorder. Primary cultures of mesDA neurons provide a tool for investigation of the molecular, biochemical and electrophysiological properties, in order to understand the development, long-term survival and degeneration of these neurons during the course of disease. Here we present a detailed method for the isolation, culturing and maintenance of midbrain dopaminergic neurons from E12.5 mouse (or E14.5 rat) embryos. Optimized cell culture conditions in this protocol result in presence of axonal and dendritic projections, synaptic connections and other neuronal morphological properties, which make the cultures suitable for study of the physiological, cell biological and molecular characteristics of this neuronal population.

The causes of degeneration of midbrain dopaminergic neurons during Parkinson&#8217;s disease are not fully understood. Cellular culture systems provide an essential tool for study of the neurophysiological properties of these neurons. Here we present an optimized protocol, which can be utilized for in vitro modeling of neurodegeneration.

Isolamento, cultura e lungo termine Manutenzione di primaria mesencefalico neuroni dopaminergici Da Brains embrionali dei roditori

Degeneration of mesencephalic dopaminergic (mesDA) neurons is the pathological hallmark of Parkinson&#8217;s diseae. Study of the biological processes ...

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

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

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

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

Analizzando Synaptic Modulazione di<em&gt; Drosophila melanogaster</em&gt; Fotorecettori dopo l&#39;esposizione alla luce prolungata

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

Application of Automated Image-guided Patch Clamp for the Study of Neurons in Brain Slices

Whole-cell patch clamp is the gold-standard method to measure the electrical properties of single cells. However, the in vitro patch clamp remains a challenging and low-throughput technique due to its complexity and high reliance on user operation and control. This manuscript demonstrates an image-guided automatic patch clamp system for in vitro whole-cell patch clamp experiments in acute brain slices. Our system implements a computer vision-based algorithm to detect fluorescently labeled cells and to target them for fully automatic patching using a micromanipulator and internal pipette pressure control. The entire process is highly automated, with minimal requirements for human intervention. Real-time experimental information, including electrical resistance and internal pipette pressure, are documented electronically for future analysis and for optimization to different cell types. Although our system is described in the context of acute brain slice recordings, it can also be applied to the automated image-guided patch clamp of dissociated neurons, organotypic slice cultures, and other non-neuronal cell types.

This protocol describes how to conduct automatic image-guided patch-clamp experiments using a system recently developed for standard in vitro electrophysiology equipment.

Applicazione di morsetto di patch automatico guidato per immagini per lo studio dei neuroni in fettine di cervello

Whole-cell patch clamp is the gold-standard method to measure the electrical properties of single cells. However, the in vitro patch clamp remains a ...

Evaluation of Synapse Density in Hippocampal Rodent Brain Slices

In the brain, synapses are specialized junctions between neurons, determining the strength and spread of neuronal signaling. The number of synapses is tightly regulated during development and neuronal maturation. Importantly, deficits in synapse number can lead to cognitive dysfunction. Therefore, the evaluation of synapse number is an integral part of neurobiology. However, as synapses are small and highly compact in the intact brain, the assessment of absolute number is challenging. This protocol describes a method to easily identify and evaluate synapses in hippocampal rodent slices using immunofluorescence microscopy. It includes a three-step procedure to evaluate synapses in high-quality confocal microscopy images by analyzing the co-localization of pre- and postsynaptic proteins in hippocampal slices. It also explains how the analysis is performed and gives representative examples from both excitatory and inhibitory synapses. This protocol provides a solid foundation for the analysis of synapses and can be applied to any research investigating the structure and function of the brain.

A protocol for accurately identifying and analyzing synapses in hippocampal slices using immunofluorescence is outlined in this article.

Valutazione di densità di sinapsi nelle fette Hippocampal del cervello del roditore

In the brain, synapses are specialized junctions between neurons, determining the strength and spread of neuronal signaling. The number of synapses is ...

Combining Optogenetics with Artificial microRNAs to Characterize the Effects of Gene Knockdown on Presynaptic Function within Intact Neuronal Circuits

The purpose of this protocol is to characterize the effect of gene knockdown on presynaptic function within intact neuronal circuits. We describe a workflow on how to combine artificial microRNA (miR)-mediated RNA interference with optogenetics to achieve selective stimulation of manipulated presynaptic boutons in acute brain slices. The experimental approach involves the use of a single viral construct and a single neuron-specific promoter to drive the expression of both an optogenetic probe and artificial miR(s) against presynaptic gene(s). When stereotactically injected in the brain region of interest, the expressed construct makes it possible to stimulate with light exclusively the neurons with reduced expression of the gene(s) under investigation. This strategy does not require the development and maintenance of genetically modified mouse lines and can in principle be applied to other organisms and to any neuronal gene of choice. We have recently applied it to investigate how the knockdown of alternative splice isoforms of presynaptic P/Q-type voltage-gated calcium channels (VGCCs) regulates short-term synaptic plasticity at CA3 to CA1 excitatory synapses in acute hippocampal slices. A similar approach could also be used to manipulate and probe the neuronal circuitry in vivo.

This protocol provides a workflow on how to combine artificial microRNA-mediated RNA interference with optogenetics to stimulate specifically presynaptic boutons with reduced expression of selective gene(s) within intact neuronal circuits.

Combinando optogenetica con microRNA artificiali per caratterizzare gli effetti del Gene atterramento su funzione presinaptica all'interno di circuiti neuronali intatto

The purpose of this protocol is to characterize the effect of gene knockdown on presynaptic function within intact neuronal circuits. We describe a ...