NIH R01 DK55619, NIH R21 CA139063

<ol>
	<li>Routh, V. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glucose-sensing+neurons:+are+they+physiologically+relevant?.">Glucose-sensing neurons: are they physiologically relevant?.</a> Physiol. Behav. 76, 403-413 (2002).</li><li>Canabal, D. D., Potian, J. G., Duran, R. G., McArdle, J. J., Routh, V. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hyperglycemia+impairs+glucose+and+insulin+regulation+of+nitric+oxide+production+in+glucose-inhibited+neurons+in+the+ventromedial+hypothalamus.">Hyperglycemia impairs glucose and insulin regulation of nitric oxide production in glucose-inhibited neurons in the ventromedial hypothalamus.</a> Am. J. Physiol. 293, 592-600 (2007).</li><li>Canabal, D. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glucose,+insulin,+and+leptin+signaling+pathways+modulate+nitric+oxide+synthesis+in+glucose-inhibited+neurons+in+the+ventromedial+hypothalamus.">Glucose, insulin, and leptin signaling pathways modulate nitric oxide synthesis in glucose-inhibited neurons in the ventromedial hypothalamus.</a> American journal of physiology. Reg. Integr. Comp. Physiol. 292, 1418-1428 (2007).</li><li>Murphy, B. A., Fakira, K. A., Song, Z., Beuve, A., Routh, V. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=AMP-activated+protein+kinase+and+nitric+oxide+regulate+the+glucose+sensitivity+of+ventromedial+hypothalamic+glucose-inhibited+neurons.">AMP-activated protein kinase and nitric oxide regulate the glucose sensitivity of ventromedial hypothalamic glucose-inhibited neurons.</a> Am. J. Physiol. Cell Physiol. 297, C750-C758 (2009).</li><li>Murphy, B. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fasting+enhances+the+response+of+arcuate+neuropeptide+Y-glucose-inhibited+neurons+to+decreased+extracellular+glucose.">Fasting enhances the response of arcuate neuropeptide Y-glucose-inhibited neurons to decreased extracellular glucose.</a> Am. J. Physiol. Cell Physiol. 296, C746-C756 (2009).</li><li>Kang, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glucokinase+is+a+critical+regulator+of+ventromedial+hypothalamic+neuronal+glucosensing.">Glucokinase is a critical regulator of ventromedial hypothalamic neuronal glucosensing.</a> Diabetes. 55, 412-420 (2006).</li><li>Kang, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prior+hypoglycemia+enhances+glucose+responsiveness+in+some+ventromedial+hypothalamic+glucosensing+neurons.">Prior hypoglycemia enhances glucose responsiveness in some ventromedial hypothalamic glucosensing neurons.</a> Reg. Integr. Comp. Physiol. 294, R784-R792 (2008).</li><li>Paxinos, G., Franklin, K. B. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The Mouse Brain in Stereotaxic Coordinates. , (2004).</li><li>Paxinos, G., Watson, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The Rat Brain in Stereotaxic Coordinates. , (1998).</li><li>Song, Z., Levin, B. E., McArdle, J. J., Bakhos, N., Routh, V. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Convergence+of+pre-+and+postsynaptic+influences+on+glucosensing+neurons+in+the+ventromedial+hypothalamic+nucleus.">Convergence of pre- and postsynaptic influences on glucosensing neurons in the ventromedial hypothalamic nucleus.</a> Diabetes. 50, 2673-2681 (2001).</li><li>Song, Z., Routh, V. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differential+effects+of+glucose+and+lactate+on+glucosensing+neurons+in+the+ventromedial+hypothalamic+nucleus.">Differential effects of glucose and lactate on glucosensing neurons in the ventromedial hypothalamic nucleus.</a> Diabetes. 54, 15-22 (2005).</li></ol>

Nous n&#39;avons rien à communiquer.

La clé pour être en mesure d&#39;étudier l&#39;activité des neurones de souris adultes est la capacité de dissocier les neurones sains. La dissociation des neurones hypothalamiques de souris adultes est plus difficile à plusieurs étapes clés du protocole par rapport aux neurones de souris juvéniles. Nous avons surmonté ce problème dans un certain nombre de façons. Faire des tranches épaisses de 500 um de cerveau minimise les dégâts mécaniques aux neurones par rapport aux habituels 250-350 um tranches uti...

Le cerveau régule l&#39;homéostasie énergétique par la neuro-endocrinien et nerveux autonome. L&#39;hypothalamus ventromédian (VMH), composé du noyau ventromédian (VMN) et le noyau arqué (ARC), est important pour la régulation centrale de l&#39;homéostasie énergétique. Neurones spécialisés de détection du glucose, dans le VMH, lien l&#39;activité neuronale et l&#39;homéostasie du glucose périphérique 1. Il existe deux types de glucose détection neurones; glucose excités (GE) neurones augmentent tandis que le glucose inhibe (GI) neurones diminuent leur activité glucose augmente extracellulaires. Neurones VMH glucose de détection sont généralement étudiés en utilisant l&#39;électrophysiologie ou potentiel imagerie de colorant sensible au calcium / membrane. La technique de patch-clamp électrophysiologie est considéré comme l&#39;étalon-or dans l&#39;étude ex vivo de l&#39;activité neuronale. Dans cette technique, une électrode de micropipette en verre est attachée à la membrane cellulaire par l&#39;intermédiaire d&#39;une résistance élevée(GQ) joint. Électrodes de patch-clamp permettent enregistrement en temps réel de l&#39;action potentielle fréquence (pince de courant) ou la conductance ionique (tension de serrage) change dans un seul neurone. Bien que la technique de patch-clamp fournit des informations détaillées en ce qui concerne les changements dans les conductances spécifiques des canaux ioniques, un inconvénient majeur est que seul un neurone peut observer à la fois. Il faut environ 30-45 minutes de l&#39;enregistrement pour vérifier que l&#39;on enregistre depuis un neurone de détection de glucose avant même de commencer un traitement expérimental spécifique. De plus, les neurones GI et GE comprennent &lt;20% de la population totale de VMH neuronale. S&#39;ajoute à ce problème est l&#39;absence, dans de nombreux cas, d&#39;un marqueur cellulaire pour identifier ces neurones. Ainsi, il est clair que malgré fournir des informations précieuses électrique que d&#39;autres techniques peuvent pas, l&#39;analyse de patch-clamp est laborieux, prend du temps et un faible rendement. L&#39;utilisation de l&#39;imagerie par fluorescence des neurones dissociés VMH permet l&#39;étude de l&#39;hundreds de neurones simultanément. Colorants sensibles au calcium peuvent être utilisés pour mesurer les changements de calcium intracellulaire, qui sont en corrélation indirectement aux variations de l&#39;activité neuronale. Colorants sensibles potentiels membranaires sont utilisés pour surveiller les changements potentiels de membrane. La mesure du potentiel de membrane cellulaire est un index plus directe de l&#39;activité neuronale par rapport à des changements dans les niveaux de calcium intracellulaire. En outre, le potentiel colorant (MPD) Imagerie de membrane détecte potentiellement petites modifications du potentiel de membrane où l&#39;action tir potentiel n&#39;est pas altérée et les niveaux de calcium intracellulaire peut pas changer. Ces deux techniques d&#39;imagerie de fluorescence ont été utilisées pour étudier VMH neurones glucose de détection de jeunes souris 2-7. Bien que les résultats sont moins détaillées que celles obtenues avec patch clamp électrophysiologie, la force d&#39;expériences d&#39;imagerie est qu&#39;ils évaluent simultanément une grande population de cellules qui comprennent inévitablement un nombre important de neurones de détection du glucose. MPD imagerie is particulièrement utile pour étudier les neurones digestifs qui sont plus uniformément localisée dans l&#39;ensemble du VMH, fournissant ainsi une population suffisante pour étudier dans le VMH dissocié (~ 15% IG). En revanche, si les neurones GE sont densément localisées au ventro-VMN et cellule région pauvre entre le CRA et VMN, ils ne représentent pas un nombre important de neurones dans le VMH (&lt;1% GE). De plus, en étudiant les neurones isolés, les astrocytes et les effets présynaptiques sont éliminés. Cela peut être un avantage dans l&#39;étude de premiers effets afin de neurones, ainsi que d&#39;un inconvénient puisque les connexions et les processus physiologiques sont perdus. Un facteur limitant dans les deux patch clamp électrophysiologie et d&#39;imagerie de colorant MPD / de calcium est la nécessité d&#39;utiliser de jeunes animaux (souris, par exemple. &lt;Ou rats âgés de 8 semaines). C&#39;est principalement en raison de l&#39;augmentation du tissu conjonctif en combinaison avec la viabilité neuronale diminué qui se produit avec l&#39;âge. Dans le cerveau tranche électrophysiologie goujons, une augmentation du tissu conjonctif, il est plus difficile de visualiser les neurones. Tissu conjonctif accrue rend également plus difficile de dissocier un grand nombre de neurones sains pour les études d&#39;imagerie. En outre, les neurones de jeunes animaux survivent plus longtemps pendant l&#39;enregistrement ou l&#39;imagerie patch clamp. Cependant, l&#39;utilisation de jeunes souris peut être une limitation majeure. L&#39;activité et / ou de réponses à des neurotransmetteurs ou des nutriments circulent neuronale changent avec l&#39;âge. Par exemple, depuis le bilan énergétique est étroitement liée à l&#39;état reproducteur, les neurones hypothalamiques régulant la balance énergétique peuvent réagir différemment en pré-vs animaux après la puberté. En outre, de nombreuses maladies nécessitent un traitement à long terme ou ne manifestent pas avant l&#39;âge adulte. Les principaux exemples de ces maladies sont l&#39;obésité alimentaire ou diabète de type 2. Depuis neurones glucose de détection sont soupçonnés de jouer un rôle dans ces maladies, nous avons développé une méthodologie pour la culture de succès adultes sains neurones HVM pour une utilisation dans l&#39;imagerie de MPD experiments.

<table border="0" cellpadding="0" cellspacing="0" width="947">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">Neurobasal-A Medium (Custom)</td>
			<td style="width:115px;">Invitrogen</td>
			<td style="width:180px;">0050128DJ</td>
			<td style="width:427px;">custom made glucose free</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">Hibernate-A Medium (Custom)</td>
			<td style="width:115px;">BrainBits</td>
			<td style="width:180px;"></td>
			<td>custom made glucose free</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:225px;">Penicillin streptomycin (20,000 U/ml)</td>
			<td style="width:115px;">Invitrogen</td>
			<td style="width:180px;">15140</td>
			<td>other vendors acceptable</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:225px;">Stericup vacuum filter units (0.22 &#956;m)</td>
			<td style="width:115px;">Millipore</td>
			<td style="width:180px;"></td>
			<td>other vendors acceptable</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">25 mm Glass coverslips</td>
			<td style="width:115px;">Warner</td>
			<td style="width:180px;">#1 25mm round</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">18 mm Glass coverslips</td>
			<td style="width:115px;">Warner</td>
			<td style="width:180px;">#1 18mm round</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">GlutaMAX</td>
			<td style="width:115px;">Invitrogen</td>
			<td style="width:180px;">35050</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">B27 minus insulin (50x)</td>
			<td style="width:115px;">Invitrogen</td>
			<td style="width:180px;">0050129SA</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">Razor blade</td>
			<td style="width:115px;">VWR</td>
			<td style="width:180px;">55411</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:225px;">Vibratome &#38; cooling chamber</td>
			<td style="width:115px;">Vibratome</td>
			<td style="width:180px;">Series 1000 Sectioning system</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">Vibratome blades</td>
			<td style="width:115px;">Polysciences</td>
			<td style="width:180px;">22370</td>
			<td>injector or double edge blades from other vendors acceptable</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">Papain, suspension</td>
			<td style="width:115px;">Worthington</td>
			<td style="width:180px;">LS003124</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">BSA, suitable for cell culture</td>
			<td style="width:115px;">Sigma</td>
			<td style="width:180px;"></td>
			<td>other vendor acceptable</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">DNAse, for cell culture</td>
			<td style="width:115px;">Invitrogen</td>
			<td style="width:180px;"></td>
			<td>other vendor acceptable</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">cloning cylinders, 6 mm x 8 mm</td>
			<td style="width:115px;">Bellco Glass</td>
			<td style="width:180px;">2090-00608</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:225px;">Membrane Potential Dye (blue)</td>
			<td style="width:115px;">Molecular Devices</td>
			<td style="width:180px;">R8042</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">In-line heater</td>
			<td style="width:115px;">Warner</td>
			<td style="width:180px;">SF-28</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">Syringe pumps</td>
			<td style="width:115px;">WPI</td>
			<td style="width:180px;">sp100i</td>
			<td>other vendor acceptable</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">Closed chamber</td>
			<td style="width:115px;">Warner</td>
			<td style="width:180px;">RC-43C</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">Polyethylene tubing</td>
			<td style="width:115px;">Warner</td>
			<td style="width:180px;">PE-90</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:225px;">Metamorph</td>
			<td style="width:115px;">Molecular Devices</td>
			<td style="width:180px;"></td>
			<td>alternate image analysis software acceptable</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">Microscope</td>
			<td style="width:115px;">Olympus</td>
			<td style="width:180px;">BX61 WI</td>
			<td>
			used with 10X&#160;objective
			</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">Camera</td>
			<td style="width:115px;">Photometrics</td>
			<td style="width:180px;">Cool Snap HQ</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:225px;">Narrow Cy3 Filter Set</td>
			<td style="width:115px;">Chroma</td>
			<td style="width:180px;">41007a</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:225px;">Illumination System</td>
			<td style="width:115px;">Sutter Instruments</td>
			<td style="width:180px;">Lambda DG-4</td>
			<td></td>
		</tr>
	</tbody>
</table>

membrane potential dye imaging of ventromedial hypothalamus neurons from adult mice to study glucose sensing

Les études de l&#39;activité neuronale sont souvent effectuées à l&#39;aide de neurones rongeurs moins de 2 mois d&#39;âge en raison des difficultés techniques liées à l&#39;augmentation du tissu conjonctif et une diminution de la viabilité neuronale qui se produisent avec l&#39;âge. Ici, nous décrivons une méthodologie pour la dissociation des neurones hypothalamiques sains provenant de souris adultes âgés. La possibilité d&#39;étudier les neurones de souris adultes d&#39;âge permet l&#39;utilisation de modèles de maladies qui se manifestent à un âge plus avancé et peut-être plus de développement précis pour certaines études. L&#39;imagerie par fluorescence des neurones dissociés peut être utilisé pour étudier l&#39;activité d&#39;une population de neurones, par opposition à l&#39;aide d&#39;électrophysiologie pour étudier un seul neurone. Ceci est particulièrement utile lors de l&#39;étude d&#39;une population neuronale hétérogène dans lequel le type désiré neuronale est rare tel que de neurones hypothalamiques de détection de glucose. Nous avons utilisé le potentiel de membrane imagerie de colorant de neurones hypothalamiques ventromédian adultes d&#39;étudier leurs réponses à changes de glucose extracellulaire. Neurones glucose de détection sont soupçonnés de jouer un rôle dans la régulation centrale de l&#39;équilibre énergétique. La possibilité d&#39;étudier la détection du glucose chez les rongeurs adultes est particulièrement utile, car la prédominance des maladies liées à l&#39;équilibre de l&#39;énergie dysfonctionnel (par exemple. L&#39;obésité) augmente avec l&#39;âge.

La dissection précise du VMH l&#39;écart des autres zones hypothalamiques est important d&#39;obtenir des résultats cohérents. L&#39;inclusion d&#39;autres domaines pourrait diluer la population neuronale VMH, changer le% de neurones dépolarisés calculées. En outre, les neurones de détection de glucose ont été identifiées dans d&#39;autres régions hypothalamiques, tels que l&#39;hypothalamus latéral, qui peut différer fonctionnellement et mécaniquement à partir de la détection de glucose dans les neuron...

Watch this Scientific Journal Video about Membrane Potential Dye Imaging of Ventromedial Hypothalamus Neurons From Adult Mice to Study Glucose Sensing at JoVE.com

Membrane Potential Dye Imaging of Ventromedial Hypothalamus Neurons From Adult Mice to Study Glucose Sensing

L&#39;activité des neurones isolés à partir de souris adultes, âgées peut être étudiée en dissociant les neurones à partir de régions spécifiques du cerveau et en utilisant l&#39;imagerie de colorant potentiel de membrane fluorescent. Par les réponses de test à des changements dans le glucose, cette technique peut être utilisée pour étudier la sensibilité au glucose des neurones hypothalamiques ventromédians adultes.

Potentiel de membrane Dye Imaging de ventromédian hypothalamus neurones de souris adulte à étudier Glucose Sensing

Studies of neuronal activity are often performed using neurons from rodents less than 2 months of age due to the technical difficulties associated with ...

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JoVE Journal

Neuroscience

13.6K vues.  Rutgers New Jersey Medical School.  L'activité des neurones isolés à partir de souris adultes, âgées peut être étudiée en dissociant les neurones à partir de régions spécifiques du cerveau et en utilisant l'imagerie de colorant potentiel de membrane fluorescent. Par les réponses de test à des changements dans le glucose, cette technique peut être utilisée pour étudier la sensibilité au glucose des neurones hypothalamiques ventromédians adultes. 

Vidéo: Membrane Potential Dye Imaging of Ventromedial Hypothalamus Neurons From Adult Mice to Study Glucose Sensing

Laser Capture Microdissection of Drosophila Peripheral Neurons

The dendritic arborization (da) neurons of the Drosophila peripheral nervous system (PNS) provide an excellent model system in which to investigate the molecular mechanisms underlying class-specific dendrite morphogenesis1,2. To facilitate molecular analyses of class-specific da neuron development, it is vital to obtain these cells in a pure population. Although a range of different cell, and tissue-specific RNA isolation techniques exist for Drosophila cells, including magnetic bead based cell purification3,4, Fluorescent Activated Cell Sorting (FACS)5-8, and RNA binding protein based strategies9, none of these methods can be readily utilized for isolating single or multiple class-specific Drosophila da neurons with a high degree of spatial precision. Laser Capture Microdissection (LCM) has emerged as an extremely powerful tool that can be used to isolate specific cell types from tissue sections with a high degree of spatial resolution and accuracy. RNA obtained from isolated cells can then be used for analyses including qRT-PCR and microarray expression profiling within a given cell type10-16. To date, LCM has not been widely applied in the analysis of Drosophila tissues and cells17,18, including da neurons at the third instar larval stage of development. 
Here we present our optimized protocol for isolation of Drosophila da neurons using the infrared (IR) class of LCM. This method allows for the capture of single, class-specific or multiple da neurons with high specificity and spatial resolution. Age-matched third instar larvae expressing a UAS-mCD8::GFP19 transgene under the control of either the class IV da neuron specific ppk-GAL420 driver or the pan-da neuron specific 21-7-GAL421 driver were used for these experiments. RNA obtained from the isolated da neurons is of very high quality and can be directly used for downstream applications, including qRT-PCR or microarray analyses. Furthermore, this LCM protocol can be readily adapted to capture other Drosophila cell types a various stages of development dependent upon the cell type specific, GAL4-driven expression pattern of GFP.

Laser Capture Microdissection of Drosophila Peripheral Neurons

In this video-article we present a method for isolating single or multiple Drosophila da neurons from third instar larvae using the infrared capture (IR) class of Laser Capture Microdissection (LCM). RNA obtained from the isolated neurons can be readily used for downstream applications including qRT-PCR or microarray analyses.

Microdissection laser des Drosophile Neurones périphériques

The dendritic arborization (da) neurons of the Drosophila peripheral nervous system (PNS) provide an excellent model system in which to investigate the ...

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Neurosciences

Determination of Mitochondrial Membrane Potential and Reactive Oxygen Species in Live Rat Cortical Neurons

Mitochondrial membrane potential (&Delta;&Psi;m) is critical for maintaining the physiological function of the respiratory chain to generate ATP. A significant loss of &Delta;&Psi;m renders cells depleted of energy with subsequent death. Reactive oxygen species (ROS) are important signaling molecules, but their accumulation in pathological conditions leads to oxidative stress. The two major sources of ROS in cells are environmental toxins and the process of oxidative phosphorylation. Mitochondrial dysfunction and oxidative stress have been implicated in the pathophysiology of many diseases; therefore, the ability to determine &Delta;&Psi;m and ROS can provide important clues about the physiological status of the cell and the function of the mitochondria. 
Several fluorescent probes (Rhodamine 123, TMRM, TMRE, JC-1) can be used to determine &Delta;&psi;m in a variety of cell types, and many fluorescence indicators (Dihydroethidium, Dihydrorhodamine 123, H2DCF-DA) can be used to determine ROS. Nearly all of the available fluorescence probes used to assess &Delta;&Psi;m or ROS are single-wavelength indicators, which increase or decrease their fluorescence intensity proportional to a stimulus that increases or decreases the levels of &Delta;&Psi;m or ROS. Thus, it is imperative to measure the fluorescence intensity of these probes at the baseline level and after the application of a specific stimulus. This allows one to determine the percentage of change in fluorescence intensity between the baseline level and a stimulus. This change in fluorescence intensity reflects the change in relative levels of &Delta;&Psi;m or ROS. In this video, we demonstrate how to apply the fluorescence indicator, TMRM, in rat cortical neurons to determine the percentage change in TMRM fluorescence intensity between the baseline level and after applying FCCP, a mitochondrial uncoupler. The lower levels of TMRM fluorescence resulting from FCCP treatment reflect the depolarization of mitochondrial membrane potential. We also show how to apply the fluorescence probe H2DCF-DA to assess the level of ROS in cortical neurons, first at baseline and then after application of H2O2. This protocol (with minor modifications) can be also used to determine changes in &#x2206;&#x03A8;m and ROS in different cell types and in neurons isolated from other brain regions.

We demonstrate application of the fluorescence indicator, TMRM, in cortical neurons to determine the relative changes in TMRM fluorescence intensity before and after application of a specific stimulus. We also show application of the fluorescence probe H2DCF-DA to assess the relative level of reactive oxygen species in cortical neurons.

Détermination des espèces d&#39;oxygène Potentiel membrane mitochondriale et réactive dans les neurones corticaux de rat en direct

Mitochondrial membrane potential (&Delta;&Psi;m) is critical for maintaining the physiological function of the respiratory chain to generate ATP.  A ...

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

Mechanical dissociation of neurons from the central nervous system has the advantage that presynaptic boutons remain attached to the isolated neuron of interest. This allows for examination of synaptic transmission under conditions where the extracellular and postsynaptic intracellular environments can be well controlled. A vibration-based technique without the use of proteases, known as vibrodissociation, is the most popular technique for mechanical isolation. A micropipette, with the tip fire-polished to the shape of a small ball, is placed into a brain slice made from a P1-P21 rodent. The micropipette is vibrated parallel to the slice surface and lowered through the slice thickness resulting in the liberation of isolated neurons. The isolated neurons are ready for study within a few minutes of vibrodissociation. This technique has advantages over the use of primary neuronal cultures, brain slices and enzymatically isolated neurons including: rapid production of viable, relatively mature neurons suitable for electrophysiological and imaging studies; superior control of the extracellular environment free from the influence of neighboring cells; suitability for well-controlled pharmacological experiments using rapid drug application and total cell superfusion; and improved space-clamp in whole-cell recordings relative to neurons in slice or cell culture preparations. This preparation can be used to examine synaptic physiology, pharmacology, modulation and plasticity. Real-time imaging of both pre- and postsynaptic elements in the living cells and boutons is also possible using vibrodissociated neurons. Characterization of the molecular constituents of pre- and postsynaptic elements can also be achieved with immunological and imaging-based approaches.

This report demonstrates a technique for mechanical isolation of individual viable neurons retaining attached presynaptic boutons. Vibrodissociated neurons have the advantages of rapid production, excellent pharmacological control and improved space-clamp without influence from neighboring cells. This method can be used for imaging of synaptic elements and patch-clamp recording.

Vibrodissociation des neurones à partir de tranches de cerveau de rongeurs pour étudier la transmission synaptique et de l&#39;image terminaisons présynaptiques

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

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

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

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

Analyse quantitative des vésicules reconstitution Piscine synaptique dans des cultures de neurones granulaires du cervelet utilisant des colorants FM

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

Isolation and Culture of Hippocampal Neurons from Prenatal Mice

Primary cultures of rat and murine hippocampal neurons are widely used to reveal cellular mechanisms in neurobiology. By isolating and growing individual neurons, researchers are able to analyze properties related to cellular trafficking, cellular structure and individual protein localization using a variety of biochemical techniques. Results from such experiments are critical for testing theories addressing the neural basis of memory and learning. However, unambiguous results from these forms of experiments are predicated on the ability to grow neuronal cultures with minimum contamination by other brain cell types. In this protocol, we use specific media designed for neuron growth and careful dissection of embryonic hippocampal tissue to optimize growth of healthy neurons while minimizing contaminating cell types (i.e. astrocytes). Embryonic mouse hippocampal tissue can be more difficult to isolate than similar rodent tissue due to the size of the sample for dissection. We show detailed dissection techniques of hippocampus from embryonic day 19 (E19) mouse pups. Once hippocampal tissue is isolated, gentle dissociation of neuronal cells is achieved with a dilute concentration of trypsin and mechanical disruption designed to separate cells from connective tissue while providing minimum damage to individual cells. A detailed description of how to prepare pipettes to be used in the disruption is included. Optimal plating densities are provided for immuno-fluorescence protocols to maximize successful cell culture. The protocol provides a fast (approximately 2 hr) and efficient technique for the culture of neuronal cells from mouse hippocampal tissue.

We provide a protocol for the culture of highly purified hippocampal neurons from prenatal mouse brains without the use of a feeder glial cell layer.

L&#39;isolement et la culture de neurones de l&#39;hippocampe de souris pendant la grossesse

Primary cultures of rat and murine hippocampal neurons are widely used to reveal cellular mechanisms in neurobiology. By isolating and growing individual ...

Genetic Study of Axon Regeneration with Cultured Adult Dorsal Root Ganglion Neurons

It is well known that mature neurons in the central nervous system (CNS) cannot regenerate their axons after injuries due to diminished intrinsic ability to support axon growth and a hostile environment in the mature CNS1,2. In contrast, mature neurons in the peripheral nervous system (PNS) regenerate readily after injuries3. Adult dorsal root ganglion (DRG) neurons are well known to regenerate robustly after peripheral nerve injuries. Each DRG neuron grows one axon from the cell soma, which branches into two axonal branches: a peripheral branch innervating peripheral targets and a central branch extending into the spinal cord. Injury of the DRG peripheral axons results in substantial axon regeneration, whereas central axons in the spinal cord regenerate poorly after the injury. However, if the peripheral axonal injury occurs prior to the spinal cord injury (a process called the conditioning lesion), regeneration of central axons is greatly improved4. Moreover, the central axons of DRG neurons share the same hostile environment as descending corticospinal axons in the spinal cord. Together, it is hypothesized that the molecular mechanisms controlling axon regeneration of adult DRG neurons can be harnessed to enhance CNS axon regeneration. As a result, adult DRG neurons are now widely used as a model system to study regenerative axon growth5-7.
Here we describe a method of adult DRG neuron culture that can be used for genetic study of axon regeneration in vitro. In this model adult DRG neurons are genetically manipulated via electroporation-mediated gene transfection6,8. By transfecting neurons with DNA plasmid or si/shRNA, this approach enables both gain- and loss-of-function experiments to investigate the role of any gene-of-interest in axon growth from adult DRG neurons. When neurons are transfected with si/shRNA, the targeted endogenous protein is usually depleted after 3-4 days in culture, during which time robust axon growth has already occurred, making the loss-of-function studies less effective. To solve this problem, the method described here includes a re-suspension and re-plating step after transfection, which allows axons to re-grow from neurons in the absence of the targeted protein. Finally, we provide an example of using this in vitro model to study the role of an axon regeneration-associated gene, c-Jun, in mediating axon growth from adult DRG neurons9.

An in vitro model for genetic study of axon regeneration using cultured adult mouse dorsal root ganglion neurons is described. The method includes a re-suspension/re-plating step to allow axon re-growth from neurons undergoing genetic manipulation. This approach is especially useful for loss-of-function studies of axon regeneration using RNAi-based protein knockdown.

Étude génétique de la régénération des axones avec cultivées adultes dorsaux neurones ganglion de la racine

It is well known that mature neurons in the central nervous system (CNS) cannot regenerate their axons after injuries due to diminished intrinsic ability ...

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.

Enregistrement colorant sensible à la tension d&#39;axones, des dendrites et des épines dendritiques des neurones individuels dans des tranches de cerveau

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

Imaging pHluorin-tagged Receptor Insertion to the Plasma Membrane in Primary Cultured Mouse Neurons

A better understanding of the mechanisms governing receptor trafficking between the plasma membrane (PM) and intracellular compartments requires an experimental approach with excellent spatial and temporal resolutions. Moreover, such an approach must also have the ability to distinguish receptors localized on the PM from those in intracellular compartments. Most importantly, detecting receptors in a single vesicle requires outstanding detection sensitivity, since each vesicle carries only a small number of receptors. Standard approaches for examining receptor trafficking include surface biotinylation followed by biochemical detection, which lacks both the necessary spatial and temporal resolutions; and fluorescence microscopy examination of immunolabeled surface receptors, which requires chemical fixation of cells and therefore lacks sufficient temporal resolution1-6 . To overcome these limitations, we and others have developed and employed a new strategy that enables visualization of the dynamic insertion of receptors into the PM with excellent spatial and temporal resolutions 7-17 . The approach includes tagging of a pH-sensitive GFP, the superecliptic pHluorin 18, to the N-terminal extracellular domain of the receptors. Superecliptic pHluorin has the unique property of being fluorescent at neutral pH and non-fluorescent at acidic pH (pH &lt; 6.0). Therefore, the tagged receptors are non-fluorescent when within the acidic lumen of intracellular trafficking vesicles or endosomal compartments, and they become readily visualized only when exposed to the extracellular neutral pH environment, on the outer surface of the PM. Our strategy consequently allows us to distinguish PM surface receptors from those within intracellular trafficking vesicles. To attain sufficient spatial and temporal resolutions, as well as the sensitivity required to study dynamic trafficking of receptors, we employed total internal reflection fluorescent microscopy (TIRFM), which enabled us to achieve the optimal spatial resolution of optical imaging (~170 nm), the temporal resolution of video-rate microscopy (30 frames/sec), and the sensitivity to detect fluorescence of a single GFP molecule. By imaging pHluorin-tagged receptors under TIRFM, we were able to directly visualize individual receptor insertion events into the PM in cultured neurons. This imaging approach can potentially be applied to any membrane protein with an extracellular domain that could be labeled with superecliptic pHluorin, and will allow dissection of the key detailed mechanisms governing insertion of different membrane proteins (receptors, ion channels, transporters, etc.) to the PM.

By tagging the extracellular domains of membrane receptors with superecliptic pHluorin, and by imaging these fusion receptors in cultured mouse neurons, we can directly visualize individual vesicular insertion events of the receptors to the plasma membrane. This technique will be instrumental in elucidating the molecular mechanisms governing receptor insertion to the plasma membrane.

Imagerie pHluorin-étiqueté insertion du récepteur de la membrane plasmique dans les neurones primaires de souris en culture

A better understanding of the mechanisms governing receptor trafficking between the plasma membrane (PM) and intracellular compartments requires an ...

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.

Tranche de cerveau Biotinylation: Une<em&gt; Ex Vivo</em&gt; Approche de Mesure région spécifique membrane de protéines plasmatiques traite des adultes neurones

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

Imaging Intracellular Ca2+ Signals in Striatal Astrocytes from Adult Mice Using Genetically-encoded Calcium Indicators

Astrocytes display spontaneous intracellular Ca2+ concentration fluctuations ([Ca2+]i) and in several settings respond to neuronal excitation with enhanced [Ca2+]i signals. It has been proposed that astrocytes in turn regulate neurons and blood vessels through calcium-dependent mechanisms, such as the release of signaling molecules. However, [Ca2+]i imaging in entire astrocytes has only recently become feasible with genetically encoded calcium indicators (GECIs) such as the GCaMP series. The use of GECIs in astrocytes now provides opportunities to study astrocyte [Ca2+]i signals in detail within model microcircuits such as the striatum, which is the largest nucleus of the basal ganglia. In the present report, detailed surgical methods to express GECIs in astrocytes in vivo, and confocal imaging approaches to record [Ca2+]i signals in striatal astrocytes in situ, are described. We highlight precautions, necessary controls and tests to determine if GECI expression is selective for astrocytes and to evaluate signs of overt astrocyte reactivity. We also describe brain slice and imaging conditions in detail that permit reliable [Ca2+]i imaging in striatal astrocytes in situ. The use of these approaches revealed the entire territories of single striatal astrocytes and spontaneous [Ca2+]i signals within their somata, branches and branchlets. The further use and expansion of these approaches in the striatum will allow for the detailed study of astrocyte [Ca2+]i signals in the striatal microcircuitry.

Imaging Intracellular Ca2+ Signals in Striatal Astrocytes from Adult Mice Using Genetically-encoded Calcium Indicators

The properties and functions of astrocyte intracellular Ca2+ signals in the striatum remain incompletely explored. We describe methods to express genetically encoded calcium indicators in striatal astrocytes using adeno-associated viruses of serotype 2/5 (AAV2/5), as well as procedures to reliably image Ca2+ signals within striatal astrocytes in situ.

Imagerie intracellulaire de Ca<sup&gt; 2+</sup&gt; Signaux dans Striatale astrocytes de souris adultes utilisant des indicateurs de calcium génétiquement codés