Questo lavoro è stato finanziato da un numero di licenza VIDI H64.09.016 da L&#39;Organizzazione olandese per la ricerca scientifica (NWO) per CPF. CPF è grato al Dott. Silvina A. Fratantoni per i suoi commenti critici e correzioni sul manoscritto finale. GMRDL / emmm sono supportati dagli olandesi Technology Foundation STW (progetto 12151 e 11350), che fa parte del NWO, e che è in parte finanziato dal Ministero degli Affari economici. Ringraziamo l&#39;Catherine Kitts e Peter Drent di Nikon Instruments Europe BV per l&#39;assistenza e il supporto. HX è stato sostenuto dalla Reale Accademia Olandese delle Arti e delle Scienze (sovvenzione 11CDP10) e WT è stata sostenuta dalla sovvenzione Organizzazione olandese per la ricerca scientifica (sovvenzione 820.02.006).

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In questo articolo viene descritto un protocollo di lavoro di immagine spine dendritiche di topo neuroni primari in coltura in vitro utilizzando SIM. Il metodo di coltura neurone dell&#39;ippocampo primaria è un adattamento del metodo originale descritto da Kaech e Banker 18. Le differenze principali sono l&#39;uso di Neurobasal/B27 terreno di coltura, che elimina la necessità di culture alimentazione astrogliali, e l&#39;aggiunta del FUDR inibitore mitotico il giorno 3 che promuove la sopravvivenz...

Una spina dendritica è una piccola protrusione della membrana del neurone. Questa caratteristica struttura è specializzata per ricevere tipicamente ingresso di una singola sinapsi e rappresenta l&#39;area di contatto fisico tra due neuroni. La maggior parte delle spine dendritiche funzionalmente maturi sono costituiti da una punta globulare, testa definito, e un collo sottile che collega la testa all&#39;albero dendritica. Tuttavia, spine non sono statici e si muovono attivamente e cambiano la loro morfologia continuamente anche nel cervello adulto 2. Entro un periodo di due settimane di tempo, colture primarie di neuroni dell&#39;ippocampo di ratto derivati ​​da tempo postnatale ritardo embrionale o all&#39;inizio sviluppano complessi pergole dendritiche con numerose sporgenze di membrana che si evolvono da inizio filipodia alle strutture della colonna vertebrale, come 3. Sulla base di questo comportamento dinamico e le altre caratteristiche, spine dendritiche sono pensati per fornire un substrato anatomico per memorizzazione e 4,5 trasmissione sinaptica. Dato the il ruolo fondamentale che le dimensioni spina dendritica e la forma sono in funzione sinaptica, è importante misurare le dimensioni con precisione. Spine variano da circa 200 a 2.000 nanometri di lunghezza e possono essere facilmente identificati da confocale a scansione laser microscopia a fluorescenza. Tuttavia, le dimensioni della colonna vertebrale diversi lunghezza sono di solito sotto la risoluzione dei tradizionali sistemi ottici &#39;, teoricamente fissato dalla diffrazione di circa 200 nanometri 6. Questi poteri non sono sufficienti per risolvere l&#39;imaging più fini dettagli, come la larghezza della colonna vertebrale colli e teste. Molto lavoro è stato dedicato a risolvere questo problema e molte relativamente nuove tecniche di microscopia a super-risoluzione hanno fornito notevoli progressi. In particolare, è possibile ottenere una risoluzione al di là del limite classico senza scartare alcuna emissione di luce utilizzando lateralmente strutturato microscopia illuminazione (SIM) in un ampio campo, microscopio confocale non 7-10. Utilizzando questa tecnica in combinazione con non-lineatecniche di microscopia r, è teoricamente possibile migliorare la risoluzione laterale del microscopio ottico per un fattore di merito 11. Tuttavia, nella maggior parte dei casi sperimentali, SIM consente di superare il limite di risoluzione di un fattore due 1. Altri super-risoluzione di tecniche di microscopia ottica, quali l&#39;esaurimento emissione stimolata (STED) microscopia a 12 e la foto-attivazione di localizzazione di microscopia (PALM) 12 sono stati applicati alla rappresentazione delle spine dendritiche. Metodi basati localizzazione, come ad esempio PALM richiedono un gran numero di immagini raw per ottenere super-risoluzione e sono quindi limitati nella velocità. D&#39;altra parte, STED può ottenere un&#39;elevata velocità di esposizione, sebbene relativamente basso numero di fotoni e piccoli campi di vista, che non può essere il caso per SIM 13. In questo articolo l&#39;obiettivo è quello di realizzare un protocollo di lavoro di immagine spine dendritiche di neuroni ippocampali di ratto primari in coltura in vitro </em&gt; utilizzando SIM. Il protocollo si compone di due fasi distinguibili: uno iniziale composto di stabilimento, lo sviluppo, trasfezione ed immunoistochimica delle primarie colture di neuroni dell&#39;ippocampo di ratto e una fase tardiva dedicata al campione di imaging.

<table>
	<tbody>
		<tr>
			<td>Fine forceps</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Big forceps</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Fine scissor</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Big scissor</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Blunt spatula</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Dissecting microscope with illumination</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Light microscope</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>37 &#176;C water bath</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Laminar flow cell culture hood</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>High-temperature dry-oven</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Bunsen burner</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Cell culture incubator (5% CO2, 37 &#176;C)</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Microcentrifuge</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Orbital shaker</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Nikon structured illumination microscope setup consisting of:</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Nikon Eclipse Ti research inverted microscope with Perfect Focus System</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Nikon CFI Apo TIRF 100x oil objective lens (N.A. 1.49)</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>4 Coherent Sapphire Lasers (458, 488, 514 and 561 nm exitation wavelength)</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>SIM Illuminator</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Nikon Stage Controller</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>MCL Nano-Drive piezo controller</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Nikon Intensilight C-HGFIE mercury lamp</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>SIM Microscope Enclosure temperature control</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Andor EM-CCD Camera iXon DU897</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>PC with Microsoft Windows 7 Home Edition</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Nikon&#8217;s NiS Elements 6.14 SIM software package</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Nikon type A immersion oil</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

imaging dendritic spines of rat primary hippocampal neurons using structured illumination microscopy

Spine dendritiche sono sporgenze che emergono dal dendrite di un neurone e rappresentano gli obiettivi primari di ingressi postsinaptici eccitatori nel cervello. I progressi tecnologici hanno identificato queste strutture come elementi fondamentali di connettività neuronale e nella plasticità sinaptica. L&#39;analisi quantitativa della morfologia della colonna vertebrale mediante microscopia ottica resta un problema essenziale a causa di limitazioni tecniche connesse con il limite intrinseco di rifrazione della luce. Spine dendritiche possono essere facilmente identificati da confocale a scansione laser microscopia a fluorescenza. Tuttavia, misurando sottili cambiamenti nella forma e dimensioni delle spine è difficile perché le dimensioni della colonna vertebrale diverse lunghezza sono generalmente più piccole rispetto alla risoluzione ottica convenzionale fissata dal limite di risoluzione teorica di microscopia luce di 200 nm. Diverse tecniche di risoluzione di super sviluppate recentemente sono stati utilizzati per immagine strutture cellulari di dimensioni inferiori a 200 nm, comprese le spine dendritiche. Tueste tecniche sono basate su operazioni di campo lontano classici e consentono quindi l&#39;uso di metodi di preparazione dei campioni esistenti e di immagine oltre la superficie di un campione. Qui descritto è un protocollo di lavoro per applicare la risoluzione strutturata eccellente illuminazione microscopia (SIM) per l&#39;imaging di spine dendritiche in colture di neuroni ippocampali primarie. Le possibili applicazioni di SIM si sovrappongono con quelli della microscopia confocale. Tuttavia, le due tecniche presentano differente applicabilità. SIM offre risoluzione laterale maggiore efficacia, mentre microscopia confocale, grazie all&#39;utilizzo di un pinhole fisica, raggiunge miglioramento risoluzione a scapito della rimozione di fuori fuoco luce. In questo protocollo, neuroni primari sono coltivate su vetrini utilizzando un protocollo standard, trasfettate con plasmidi di DNA codificanti proteine ​​fluorescenti e ripreso con SIM. L&#39;intero protocollo qui descritto dura circa due settimane, perché spine dendritiche vengono esposte dopo 16-17 giorni in vitro, quandosviluppo dendritico è ottimale. Dopo il completamento del protocollo, spine dendritiche possono essere ricostruiti in 3D da una serie di SIM stack di immagini utilizzando software specializzati.

Qui descritto è un protocollo di lavoro standardizzato per l&#39;imaging spine dendritiche di topo neuroni primari in vitro utilizzando SIM. Il flusso di lavoro protocollo ei suoi passi fondamentali sono illustrati nella Figura 1. Nel complesso, il protocollo richiede circa 2 settimane di lavoro sperimentale separate in una prima fase di preparazione del campione, compresi cultura, sviluppo e trasfezione di neuroni ippocampali di ratto primari e immunoistochimica e seconda fase dell&#39;imagin...

Watch this Scientific Journal Video about Imaging Dendritic Spines of Rat Primary Hippocampal Neurons using Structured Illumination Microscopy at JoVE.com

Imaging Dendritic Spines of Rat Primary Hippocampal Neurons using Structured Illumination Microscopy

Questo articolo descrive un protocollo di lavoro di immagine spine dendritiche di neuroni dell&#39;ippocampo in vitro utilizzando Structured Illumination Microscopy (SIM). Microscopia super-risoluzione usando SIM fornisce risoluzione di immagine notevolmente oltre il limite di diffrazione della luce in tutte le tre dimensioni spaziali, permettendo l&#39;imaging di singole spine dendritiche con maggiore dettaglio.

Imaging spine dendritiche di Rat Primaria neuroni dell&#39;ippocampo utilizzando Structured Illumination Microscopy

Dendritic spines are protrusions emerging from the dendrite of a neuron and represent the primary postsynaptic targets of excitatory inputs in the brain. ...

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JoVE Journal

Neuroscience

15.7K Views.  University of Amsterdam.  Questo articolo descrive un protocollo di lavoro di immagine spine dendritiche di neuroni dell'ippocampo in vitro utilizzando Structured Illumination Microscopy (SIM). Microscopia super-risoluzione usando SIM fornisce risoluzione di immagine notevolmente oltre il limite di diffrazione della luce in tutte le tre dimensioni spaziali, permettendo l'imaging di singole spine dendritiche con maggiore dettaglio. 

Video: Imaging Dendritic Spines of Rat Primary Hippocampal Neurons using Structured Illumination Microscopy

Nucleofection and Primary Culture of Embryonic Mouse Hippocampal and Cortical Neurons

Hippocampal and cortical neurons have been used extensively to study central nervous system (CNS) neuronal polarization, axon/dendrite outgrowth, and synapse formation and function. An advantage of culturing these neurons is that they readily polarize, forming distinctive axons and dendrites, on a two dimensional substrate at very low densities. This property has made them extremely useful for determining many aspects of neuronal development. Furthermore, by providing glial conditioning for these neurons they will continue to develop, forming functional synaptic connections and surviving for several months in culture. In this protocol we outline a technique to dissect, culture and transfect embryonic mouse hippocampal and cortical neurons. Transfection is accomplished by electroporating DNA into the neurons before plating via nucleofection. This protocol has the advantage of expressing fluorescently-tagged fusion proteins early in development (~4-8hrs after plating) to study the dynamics and function of proteins during polarization, axon outgrowth and branching. We have also discovered that this single transfection before plating maintains fluorescently-tagged fusion protein expression at levels appropriate for imaging throughout the lifetime of the neuron (&gt; 2 months in culture). Thus, this methodology is useful for studying protein localization and function throughout CNS development with little or no disruption of neuronal function.

This protocol outlines the steps required to dissect, transfect via electroporation and culture mouse hippocampal and cortical neurons. Short-term cultures may be used for studies of axon outgrowth and guidance, while long-term cultures can be used for studies of synaptogenesis and dendritic spine analysis.

Nucleofection e cultura primaria di neuroni embrionali di topo ippocampale e corticale

Hippocampal and cortical neurons have been used extensively to study central nervous system (CNS) neuronal polarization, axon/dendrite outgrowth, and ...

Ricerca

Neuroscienze

Fluorescence Recovery After Photobleaching (FRAP) of Fluorescence Tagged Proteins in Dendritic Spines of Cultured Hippocampal Neurons

FRAP has been used to quantify the mobility of GFP-tagged proteins. Using a strong excitation laser, the fluorescence of a GFP-tagged protein is bleached in the region of interest. The fluorescence of the region recovers when the unbleached GFP-tagged protein from outside of the region diffuses into the region of interest. The mobility of the protein is then analyzed by measuring the fluorescence recovery rate. This technique could be used to characterize protein mobility and turnover rate.
In this study, we express the (enhanced green fluorescent protein) EGFP vector in cultured hippocampal neurons. Using the Zeiss 710 confocal microscope, we photobleach the fluorescence signal of the GFP protein in a single spine, and then take time lapse images to record the fluorescence recovery after photobleaching. Finally, we estimate the percentage of mobile and immobile fractions of the GFP in spines, by analyzing the imaging data using ImageJ and Graphpad softwares.
This FRAP protocol shows how to perform a basic FRAP experiment as well as how to analyze the data.

Fluorescence Recovery After Photobleaching FRAP of Fluorescence Tagged Proteins in Dendritic Spines of Cultured Hippocampal Neurons

FRAP has been used to quantify the mobility of Green Fluorescence Protein (GFP)-tagged proteins in cultured cells. We examined the mobile/immobile fractions of the GFP by analyzing the fluorescence recovery percentage after photobleaching. In this study, FRAP was performed at spines of hippocampal neurons.

Recupero della fluorescenza dopo photobleaching (FRAP) di fluorescenza proteine ​​Tagged in spine dendritiche di colture di neuroni ippocampali

FRAP has been used to quantify the mobility of GFP-tagged proteins. Using a strong excitation laser, the fluorescence of a GFP-tagged protein is bleached ...

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 ...

Calcium Phosphate Transfection of Primary Hippocampal Neurons

Calcium phosphate precipitation is a convenient and economical method for transfection of cultured cells. With optimization, it is possible to use this method on hard-to-transfect cells like primary neurons. Here we describe our detailed protocol for calcium phosphate transfection of hippocampal neurons cocultured with astroglial cells.

Fosfato di calcio trasfezione di primaria neuroni dell&#39;ippocampo

Calcium phosphate precipitation is a convenient and economical method for transfection of cultured cells. With optimization, it is possible to use this ...

Two-Photon in vivo Imaging of Dendritic Spines in the Mouse Cortex Using a Thinned-skull Preparation

In the mammalian cortex, neurons form extremely complicated networks and exchange information at synapses. Changes in synaptic strength, as well as addition/removal of synapses, occur in an experience-dependent manner, providing the structural foundation of neuronal plasticity. As postsynaptic components of the most excitatory synapses in the cortex, dendritic spines are considered to be a good proxy of synapses. Taking advantages of mouse genetics and fluorescent labeling techniques, individual neurons and their synaptic structures can be labeled in the intact brain. Here we introduce a transcranial imaging protocol using two-photon laser scanning microscopy to follow fluorescently labeled postsynaptic dendritic spines over time in vivo. This protocol utilizes a thinned-skull preparation, which keeps the skull intact and avoids inflammatory effects caused by exposure of the meninges and the cortex. Therefore, images can be acquired immediately after surgery is performed. The experimental procedure can be performed repetitively over various time intervals ranging from hours to years. The application of this preparation can also be expanded to investigate different cortical regions and layers, as well as other cell types, under physiological and pathological conditions.

Two-Photon in vivo Imaging of Dendritic Spines in the Mouse Cortex Using a Thinned-skull Preparation

Time-lapse imaging in the living animal provides valuable information on structural reorganization in the intact brain. Here, we introduce a thinned-skull preparation that allows transcranial imaging of fluorescently labeled synaptic structures in the living mouse cortex by two-photon microscopy.

Two-Photon<em&gt; In vivo</em&gt; Imaging di spine dendritiche nella corteccia mouse Uso un teschio Diluito-Preparazione

In the mammalian cortex, neurons form extremely complicated networks and exchange information at synapses. Changes in synaptic strength, as well as ...

Live Images of GLUT4 Protein Trafficking in Mouse Primary Hypothalamic Neurons Using Deconvolution Microscopy

Type 2 diabetes mellitus (T2DM) is a global health crisis which is characterized by insulin signaling impairment and chronic inflammation in peripheral tissues. The hypothalamus in the central nervous system (CNS) is the control center for energy and insulin signal response regulation. Chronic inflammation in peripheral tissues and imbalances of certain chemokines (such as CCL5, TNF&#945;, and IL-6) contribute to diabetes and obesity. However, the functional mechanism(s) connecting chemokines and hypothalamic insulin signal regulation still remain unclear.
In vitro primary neuron culture models are convenient and simple models which can be used to investigate insulin signal regulation in hypothalamic neurons. In this study, we introduced exogeneous GLUT4 protein conjugated with GFP (GFP-GLUT4) into primary hypothalamic neurons to track GLUT4 membrane translocation upon insulin stimulation. Time-lapse images of GFP-GLUT4 protein trafficking were recorded by deconvolution microscopy, which allowed users to generate high-speed, high-resolution images without damaging the neurons significantly while conducting the experiment. The contribution of CCR5 in insulin regulated GLUT4 translocation was observed in CCR5 deficient hypothalamic neurons, which were isolated and cultured from CCR5 knockout mice. Our results demonstrated that the GLUT4 membrane translocation efficiency was reduced in CCR5 deficient hypothalamic neurons after insulin stimulation.

This protocol describes a technique for observation of real-time Green Fluorescence Protein (GFP) tagged Glucose Transporter 4 (GLUT4) protein trafficking upon insulin stimulation and characterization of the biological role of CCR5 in the insulin&#8211;GLUT4 signaling pathway with Deconvolution Microscopy.

Immagini in diretta della proteina GLUT4 tratta di neuroni ipotalamici primario del Mouse usando la microscopia di Deconvolution

Type 2 diabetes mellitus (T2DM) is a global health crisis which is characterized by insulin signaling impairment and chronic inflammation in peripheral ...

Generation of Neurospheres from Mixed Primary Hippocampal and Cortical Neurons Isolated from E14-E16 Sprague Dawley Rat Embryo

Primary neuron culture is an essential technique in the field of neuroscience. To gain deeper mechanistic insights into the brain, it is essential to have a robust in vitro model that can be exploited for various neurobiology studies. Though primary neuron cultures (i.e., long-term hippocampal cultures) have provided scientists with models, it does not yet represent the complexity of brain network completely. In the wake of these limitations, a new model has emerged using neurospheres, which bears a closer resemblance to the brain tissue. The present protocol describes the plating of high and low densities of mixed cortical and hippocampal neurons isolated from the embryo of embryonic day 14-16 Sprague Dawley rats. This allows for the generation of neurospheres and long-term primary neuron culture as two independent platforms to conduct further studies. This process is extremely simple and cost-effective, as it minimizes several steps and reagents previously deemed essential for neuron culture. This is a robust protocol with minimal requirements that can be performed with achievable results and further used for a diversity of studies related to neuroscience.

Presented here is a protocol for the spontaneous generation of neurospheres enriched in neural progenitor cells from high density plated neurons. During the same experiment, when neurons are plated at a lower density, the protocol also results in prolonged primary rat neuron cultures.

Generazione di neurosfere da neuroni ippocampali primari misti e corticali isolati da E14-E16 Sprague Dawley Rat Embryo

Primary neuron culture is an essential technique in the field of neuroscience. To gain deeper mechanistic insights into the brain, it is essential to have ...

3D Modeling of Dendritic Spines with Synaptic Plasticity

Computational modeling of diffusion and reaction of chemical species in a three-dimensional (3D) geometry is a fundamental method to understand the mechanisms of synaptic plasticity in dendritic spines. In this protocol, the detailed 3D structure of the dendrites and dendritic spines is modeled with meshes on the software Blender with CellBlender. The synaptic and extrasynaptic regions are defined on the mesh. Next, the synaptic receptor and synaptic anchor molecules are defined with their diffusion constants. Finally, the chemical reactions between synaptic receptors and synaptic anchors are included and the computational model is solved numerically with the software MCell. This method describes the spatiotemporal path of every single molecule in a 3D geometrical structure. Thus, it is very useful to study the trafficking of synaptic receptors in and out of the dendritic spines during the occurrence of synaptic plasticity. A limitation of this method is that the high number of molecules slows the speed of the simulations. Modeling of dendritic spines with this method allows the study of homosynaptic potentiation and depression within single spines and heterosynaptic plasticity between neighbor dendritic spines.

The protocol develops a three-dimensional (3D) model of a dendritic segment with dendritic spines for modeling synaptic plasticity. The constructed mesh can be used for computational modeling of AMPA receptor trafficking in the long-term synaptic plasticity using the software program Blender with CellBlender and MCell.

Modellazione 3D di spine dendritiche con plasticità sinaptica

Computational modeling of diffusion and reaction of chemical species in a three-dimensional (3D) geometry is a fundamental method to understand the ...

Imaging Dendritic Spines in Caenorhabditis elegans

Dendritic spines are specialized sites of synaptic innervation modulated by activity and serve as substrates for learning and memory. Recently, dendritic spines have been described for DD GABAergic neurons as the input sites from presynaptic cholinergic neurons in the motor circuit of Caenorhabditis elegans. This synaptic circuit can now serve as a powerful new in vivo model of spine morphogenesis and function that exploits the facile genetics and ready accessibility of C. elegans to live-cell imaging. 
This protocol describes experimental strategies for assessing DD spine structure and function. In this approach, a super-resolution imaging strategy is used to visualize the intricate shapes of actin-rich dendritic spines. To evaluate the DD spine function, the light-activated opsin, Chrimson, stimulates the presynaptic cholinergic neurons, and the calcium indicator, GCaMP, reports the evoked calcium transients in postsynaptic DD spines. Together, these methods comprise powerful approaches for identifying genetic determinants of dendritic spines in C. elegans that could also direct spine morphogenesis and function in the brain.

Imaging Dendritic Spines in Caenorhabditis elegans

Dendritic spines are important cellular features of the nervous system. Here live imaging methods are described for assessing the structure and function of dendritic spines in C. elegans.&#160;These approaches support the development of mutant screens for genes that define dendritic spine shape or function.

Imaging delle spine dendritiche in Caenorhabditis elegans

Dendritic spines are specialized sites of synaptic innervation modulated by activity and serve as substrates for learning and memory. Recently, dendritic ...

Serial Block-Face Scanning Electron Microscopy (SBEM) for the Study of Dendritic Spines

Three-dimensional electron microscopy (3D EM) gives a possibility to analyze morphological parameters of dendritic spines with nanoscale resolution. In addition, some features of dendritic spines, such as volume of the spine and post-synaptic density (PSD) (representing post-synaptic part of the synapse), presence of presynaptic terminal, and smooth endoplasmic reticulum or atypical form of PSD (e.g., multi-innervated spines), can be observed only with 3D EM. By employing serial block-face scanning electron microscopy (SBEM) it is possible to obtain 3D EM data easier and in a more reproducible manner than when performing traditional serial sectioning. Here we show how to prepare mouse hippocampal samples for SBEM analysis and how this protocol can be combined with immunofluorescence study of dendritic spines. Mild fixation perfusion allows us to perform immunofluorescence studies with light microscopy on one half of the brain, while the other half was prepared for SBEM. This approach reduces the number of animals to be used for the study.

Serial Block-Face Scanning Electron Microscopy SBEM for the Study of Dendritic Spines

Serial Block-Face Scanning Electron Microscopy (SBEM) is applied to image and analyze dendritic spines in the murine hippocampus.

Microscopia elettronica a scansione a blocchi seriali (SBEM) per lo studio delle spine dendritiche

Three-dimensional electron microscopy (3D EM) gives a possibility to analyze morphological parameters of dendritic spines with nanoscale resolution. In ...