Unterstützung wurde von startup-Mittel aus der Pharmakologie und Chemische Biologie-Abteilung an der Universität von Pittsburgh School of Medicine. Bestätigung der Jacob Labor-Mitglieder, die an der Video-Vorlage beigetragen: Nicholas Graff.

Alle unten beschriebenen Protokolle sind in Übereinstimmung mit der IACUC und IRB Institutional Review Boards der University of Pittsburgh School of Medicine. 1. Vorbereitung der Hippocampus Neuronale Kulturen in Gewebekultur Hood Hinweis: Verwenden steriler Technik und Reagenzien während Protokoll 1. <ol><li> Vorbereitung Poly-D-Lysin (0,1 mg / ml in H 2 O) beschichteten Deckgläsern als Substrat für die neuronale Kultur. <ol><li> Zeigen 4-5 runden Glasdeckgläschen in jedem 3,5 cm Gewebekulturschale. </li><li> Punkt 70 ul Poly-D-Lysin auf jede 12 mm Deckglas. Hinweis: Für die Live-Aufnahmen, ein Glasboden 3,5-cm-Gewebekulturschale verwendet werden können (vor Ort 200 ul Poly-D-Lysin auf eingebettete 14 mm Deckglas). </li><li> Lassen Sie die zubereiteten Speisen in der Gewebekultur Haube O / N. Um Poly-D-Lysin-Verdampfung zu minimieren und halten sterile Oberflächen in der Gewebekultur Haube, und schließen Sie den Fensterflügel und schalten Sie the Gebläse O / N. Hinweis: UV-Lampen werden während der O / N Inkubation verwendet. </li><li> Am nächsten Morgen, waschen das Geschirr 3x mit 2 ml H 2 O. </li><li> Nach dem Entfernen der letzten H 2 O waschen, 2 ml von Medien, um je 3,5 cm Schale und lassen Gerichte in Inkubator, bis bereit, die Neuronen in Schritt 1.4 plattieren. </li></ol></li><li> Hippocampus-Neuronen aus embryonalen Tag 18-19 (E18-19) Ratten (von 22 Goslin modifiziert) vorbereitet. </li><li> Transfektion von frisch gewonnenen Neuronen am Tag der Kultivierung mit 1-4 ug maxiprepped DNA-Konstrukt. Hinweis: typischerweise 3 ug DNA in 1-2 Millionen Neuronen transfiziert mit einer Lebensfähigkeit von 50% und eine Transfektionseffizienz von 60% (z. B. beginnend mit 2 Millionen Neuronen ((2 x 10 6 Neuronen x 0.5) 0.6) sieht ca. 1 Million Neuronen;.. davon 600.000 transfiziert 1 Unterschiedliche Mengen an DNA-Konstrukt kann bei der Fehlersuche potenzielle Probleme von transfiziert werdenÜberexpression, gefolgt von entsprechenden Charakterisierung Konstrukt Lokalisation und Funktion. </li><li> Platte der transfizierten Neuronen auf Poly-D-Lysin beschichtete Deckgläser mit einer endgültigen Dichte von etwa 200.000 Neuronen pro 3,5 cm Schale. Hinweis: Für eine Glasbodenschale, Teller 40.000-50.000 Neuronen auf der 14 mm Glasfläche. </li><li> Ersetzen Sie die Medien 4-24 Stunden nach der Herstellung der neuronalen Kulturen, dann lassen Neuronen im Inkubator entwickeln, bis 14-17 Tage in vitro (DIV) oder gewünscht Bühne. </li></ol> 2. Endozytose Assay ACHTUNG: Hinweis auf α-Bungarotoxin Tubocurarin und Abfallkosten: <ol><li> Handhabung aller Peptid Neurotoxine wird innerhalb der Richtlinien der biologischen Sicherheitsstufe-2 (BL-2) Forschungsprotokolle empfohlen. Alle geeignete Schutzkleidung getragen werden. Lyophilisiert Toxin Pulver sollte nach den Anweisungen des Herstellers rekonstituiert. Toxin Abfall should unter Beachtung der Umweltschutz und Sicherheit Richtlinien der Regierungsinstitution entsorgt werden. </li><li> Um potenzielle Peptidaggregate, die während der Lagerung gebildet haben können, sollten α-Bungarotoxin Aliquots kurz vor Gebrauch zentrifugiert, und der Überstand sollte für den Versuch verwendet werden. </li><li> α-Bungarotoxin (Bgt) Bestände zu einer Konzentration von 1 mg / ml in sterilem H 2 O bei -20 ° C resuspendiert und in 10 &amp;mgr; l Aliquots gelagert Fluoreszenz gekoppelt Bgt Bestände bei 3 pg / ml verwendet. Tubocurarin wird in einer Endkonzentration von 150 &amp;mgr; M verwendet. </li></ol><ol><li> Stellen Sie Tisch Heizblock auf 16 ° C im Kühlraum mit dünnen Aluminium-oder Edelstahlplatte an der Spitze. Alternativ, falls vorhanden, eine Tisch Kühl / Heizvorrichtung kann für jeden Schritt benötigt 16 ° C eingesetzt werden </li><li> Kühlen extrazellulären Hepes-gepufferter Salzlösung (HBS, enthaltend in mM: 135 NaCl, 4,7 KCl, 10 HEPES, 11 Glucose, 1,2 MgCl 2, 2,5CaCl 2, pH 7,4) auf 16 ° C in einem Wasserbad. </li><li> Über Neuron Gerichte Aluminiumplatte bei 16 ° C und cool für 5 min. </li><li> Medien entfernen (halten konditionierten Medien-und Reserve in Inkubator für Schritt 2.8, Endozytose Testzeit Punkte) und ersetzen mit 1 ml 16 ° C HBS + Tubocurarin (150 uM) für 2 min. </li><li> Entfernen HBS + Tubocurarin zu beschrifteten Abfallbehälter und ersetzen mit 1 ml 16 ° C HBS + Tubocurarin (150 uM) + α-Bungarotoxin Alexa 594 [3 pg / ml], Inkubation bei 16 ° C für 15 min. </li><li> Entfernen HBS + + Tubocurarin α-Bungarotoxin Alexa 594 Abfallbehälter beschriftet und Geschirr spülen 3x mit 2 ml 16 ° C HBS (die Waschungen kann durch Absaugen im Vakuum-Kolben, der 50 ml 50% Bleichmittel gesammelt werden). </li><li> Für Live-Bildgebung Zeitreihen-Experimenten nach Rezeptor Endozytose mit einem Glasboden-3.5 cm Kulturschale, die Schritte 2.1-2.6, dann Transfer Gericht erhitzt Bühne(Peltier-Vorrichtung) am Mikroskop, und beginnen Sie mit einem konfokalen Imaging-oder TIRF-Mikroskop-Setup. </li><li> Übertragen T = 0 Zeitpunkt Deckgläser in eine Schale von RT 4% Paraformaldehyd / 4% Saccharose für 20 min, weiter mit anderen Deckgläser zu Schritt 2.9. </li><li> Für andere Zeitpunkte, zu ersetzen HBS Anlage mit 37 ° C ins Gleichgewicht Medien (in Schritt 2.4 reserviert) und zum Brutkasten für Endozytose bei 37 ° C. Hinweis: vorgeschlagen, zusätzliche Zeitpunkten T = 15, 30 und 60 auf. </li><li> Zu den Zeitpunkten benötigt, nehmen Sie Gerichte aus Inkubator, schnell waschen zweimal mit 2 ml DPBS RT (DPBS kein Kalzium, Magnesium), dann in 4% Paraformaldehyd / 4% Saccharose für 20 Minuten zu beheben. </li><li> Nach 20 min Fixierung, entfernen Sie 4% Paraformaldehyd / 4% Saccharose in Abfallgebinde und Geschirr spülen zweimal mit 2 ml DPBS RT. </li><li> Deck Inkubation bei RT für 10 min in der Immunfluoreszenz Blocklösung (Blocklösung = 5% Pferdeserum, 0,5% BSA in DPBS), enthaltend 0,2% Triton X-100 zu Durchläsize die Neuronen und ermöglichen anti-GFP-Immunfärbung von intrazellulären Rezeptor-Pool und / oder Kennzeichnung von anderen Proteinen von Interesse. </li><li> Entfernen Block + 0,2% Triton X-100 und Inkubation Deckgläser in Immunblock Lösung ohne Triton X-100 für 20-30 min. </li><li> Führen primären Antikörper-Inkubationen von Deckgläsern in Block mehrere Stunden bei RT oder O / N bei 4 ° C. Hinweis: Inkubation von Deckgläsern mit Vorwahlen bei 4 ° CO / N routinemäßig produziert verbesserte Immunfluoreszenz Ergebnisse. </li><li> Wash Deckgläser 3x mit DPBS (5 min für jeden Waschschritt). </li><li> Deck inkubieren mit sekundären Antikörpern in Blocklösung für 1 h bei RT. </li><li> Wash Deckgläser 3x mit DPBS (5 min für jeden Waschschritt). </li><li> Deckmontage, Handhabung jedes Deckglas individuell: Entfernen Sie überschüssige Flüssigkeit von der Rückseite des Deckglases mit Laborgewebe, dann invertieren Deckglas auf 4 ul Eindeckmedium auf einem Glasträger. </li><li> Veröffentlichung Folien bei RT trocknen abgedeckt 30 min dann stErz bei 4 ° C bis bereit zu Mikroskopie durchzuführen. </li><li> Bildaufnahme und Auswertung des Experiments mit konfokaler Mikroskopie (blind Versuchsbedingung). 60X NA 1.49 Öl-Immersionsobjektiv mit folgenden Lasern: Argongas 488 nm, 561-Diode, 640 Diode. <ol><li> Mit den gleichen Einstellungen Bildaufnahme, erwerben einzigen Z Schnittbilder mit der neuronalen Zellkörper und mehrere dendritischen Prozesse im Fokus. </li><li> Quantifizierung von α-Bungarotoxin Alexa Fluoreszenzsignal und GFP-Immunfärbung auf 20 &amp;mgr; m von 3-4 proximalen Dendriten pro Neuron unter Verwendung derselben Schwelle für die Analyse aller Daten Endozytose. </li><li> Analysieren von Daten 10-12 Neuronen für jeden Zeitpunkt, Wiederholung des Experiments mit mehreren unabhängigen neuronalen Kulturen. </li></ol></li></ol>

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Die Autoren haben nichts zu offenbaren.

Die hier beschriebenen BBS Basis fest und Live-Techniken können verwendet werden, um Rezeptor oder anderen Plasmamembranprotein Handel in Zelllinien, Neuronen und anderen primären Zellen zu verfolgen. Dieses Verfahren wurde verwendet, um Membran Einsetzen und Entfernen der Liganden-gesteuerte Ionenkanäle und GPCR untersuchen und Veränderungen in den Handel zu beurteilen aufgrund der Gegenwart der Rezeptor-Agonisten und Modulatoren. Schwerpunkte sind entsprechende Lokalisierung der Tag, um eine extrazelluläre Lage u...

Die Verwendung von fluoreszenz gekoppelt α-Bungarotoxin Rezeptor Lokalisation und Dynamik zu studieren wurde in Studien der Nikotinacetylcholinrezeptor 13-15, endogenen Ziel des Toxins Pionierarbeit geleistet. Anschließend Einbau des minimalen Bgt bindende Peptid (BBS) wurde genutzt, um Menschenhandel beider erregenden und hemmenden Liganden-gesteuerte Ionenkanäle und G-Protein-gekoppelten Rezeptoren 2,10,16-21 studieren. Das BBS-basierte Technik bietet Vorteile gegenüber anderen Ansätzen für den Menschenhandel Studien wie Oberflächen Biotinylierung Methoden, Antikörpermarkierung von lebenden Zellen mit Antikörpern gegen die extrazelluläre Epitope und Fluorescence Recovery After Photobleaching (FRAP) verwendet. Während Zelloberflächen Biotinylierung freien Amine kovalent modifiziert, mit dem Potential, die zelluläre Aktivität beeinflussen. Antikörper basierte Studien haben oft durch Oberflächenantigen Clustering oder Deckelung, die Menschenhandel Ereignisse verändern kann behindert. Aufgrund der Bleichstufe für FRAP sTUDIEN, ist ein wichtiges Anliegen Beschädigung der zugrunde liegenden zellulären Struktur. Ein zusätzlicher Vorteil ist, dass BBS-markierten Konstrukte können auch für biochemische Methoden mit Biotin-gekoppelten Rezeptor Bungarotoxin zu beurteilen Handel verwendet werden. Dieses Verfahren ist leicht auf Zelllinien und Primärzellen. Zur Verwendung in Zellen, die nikotinergen Acetylcholin (nAChR)-Rezeptoren exprimieren, muß die nAChR-Antagonisten Tubocurarin gesamten Protokoll verwendet werden, wie angegeben. Durchführen einer einfachen Oberfläche Bgt Kennzeichnung (entspricht der T = 0 Zeitpunkt für die Endozytose-Protokoll) auf nicht-transfizierten Zellen in Abwesenheit von Tubocurarin wird Nachweis von endogenen nAChR bereitzustellen. Eine wichtige Überlegung für die Verwendung dieser Technik entsprechende Einsetzen der BBS, so dass es an einer extrazellulären Stelle, wenn das Protein von Interesse an die Plasmamembran geliefert vorliegt. Zum Beispiel können die N-terminalen Domänen von GABAAR Einheiten befinden sich in den Bläschen Lumen während TRAFHandels und werden nach Einsetzen Rezeptor in der Plasmamembran der extrazellulären, so dass spezifische Markierung von Zelloberflächenrezeptoren und die Bewertung ihrer Entfernung von der Zelloberfläche von endozytischen Veranstaltungen. Wir haben früher gezeigt, dass die Zugabe von GFP, myc oder BBS Epitope dieser Domäne GABAAR Einheiten funktionell still. Standardkontrollen durchgeführt werden sollte, um sicherzustellen, dass das markierte Protein wird in ähnlichen Mengen zu einer unbezeichnet Konstrukt exprimiert wird, dass es angemessen lokalisiert, und dass es keinen Einfluss auf die Rezeptorfunktion. Diese Charakterisierung von transfizierten Konstrukte werden auch bei der Fehlersuche die Überexpression Anliegen zu unterstützen.

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			<td height="42" style="height:42px;width:227px;">Name of Material/ Equipment</td>
			<td style="width:201px;">Company</td>
			<td style="width:196px;">Catalog Number</td>
			<td style="width:187px;">Comments/Description</td>
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			<td height="20" style="height:20px;width:227px;">P3 Primary Cell 4D kit&#160;</td>
			<td style="width:201px;">Lonza</td>
			<td style="width:196px;">V4XP-3024</td>
			<td></td>
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			<td height="40" style="height:40px;width:227px;">&#945;-bungarotoxin, Alexa Fluor 647 conjugate</td>
			<td style="width:201px;">Molecular Probes</td>
			<td style="width:196px;">B35450</td>
			<td></td>
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			<td height="40" style="height:40px;width:227px;">&#945;-bungarotoxin, Alexa Fluor 488 conjugate</td>
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			<td style="width:196px;">B13422</td>
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			<td height="40" style="height:40px;width:227px;">&#945;-bungarotoxin, Alexa Fluor 594 conjugate</td>
			<td style="width:201px;">Molecular Probes</td>
			<td style="width:196px;">B13423</td>
			<td></td>
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			<td height="20" style="height:20px;width:227px;">(+)-Tubocurarine chloride</td>
			<td style="width:201px;">Tocris</td>
			<td style="width:196px;">2820</td>
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			<td height="20" style="height:20px;width:227px;">mounting medium&#160;</td>
			<td>DAKO</td>
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			<td height="20" style="height:20px;">DPBS no calcium,magnesium&#160;</td>
			<td style="width:201px;">Invitrogen&#160;</td>
			<td style="width:196px;">14190-136</td>
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			<td height="20" style="height:20px;width:227px;">poly-D-lysine&#160;</td>
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		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:227px;">gephyrin antibody</td>
			<td>Synaptic Systems</td>
			<td>147 011</td>
			<td>1:300</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:227px;">VIAAT/VGAT antibody</td>
			<td>Synaptic Systems</td>
			<td>131 002</td>
			<td>1:1000</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:227px;">anti GFP</td>
			<td style="width:201px;">Life Technologies</td>
			<td>A6455</td>
			<td>1:2000</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:227px;">glass bottom tissue culture dish</td>
			<td style="width:201px;">MatTek Corporation</td>
			<td colspan="2">P35G-1.5-14-C - Mattek Dishes</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:227px;">coverslips (round cover glass), #1 thickness, 12 mm</td>
			<td style="width:201px;">Warner Instruments</td>
			<td style="width:196px;">640-0702</td>
			<td></td>
		</tr>
	</tbody>
</table>

using an &#945;-bungarotoxin binding site tag to study gaba a receptor membrane localization and trafficking

Es wird zunehmend deutlich, dass Neurotransmitter-Rezeptoren, einschließlich ionotropen GABA A-Rezeptoren (GABAAR), Ausstellungshochdynamischen Handel und Zelloberfläche Mobilität 7.1. Rezeptorzelloberflächenlokalisierung und Endozytose zu untersuchen, die hier beschriebenen Verfahren kombiniert die Verwendung von Fluoreszenz-α-Bungarotoxin-Zellen, die mit Konstrukten, die eine α-Bungarotoxin (Bgt) Bindungsstelle (BBS). Die BBS (WRYYESSLEPYPD) an der α-Untereinheit des nikotinischen Acetylcholinrezeptors Muskeln, die mit hoher Affinität Bgt 8,9 bindet. Einbau des BBS-Website ermöglicht Fläche Lokalisierung und Messung von Rezeptor Einsetzen oder Entfernen mit Applikation exogener Fluoreszenz Bgt, wie zuvor in der Verfolgung von GABAA-und GABAB-Rezeptoren 2,10 metabo beschrieben. Neben der BBS-Website, die zwischen den Aminosäuren 4 und 5 des reifen GABAAR Untereinheit durch Standard m eingesetzt wir eine pH-sensitive GFP (pHGFP 11)olecular Biologie und PCR-Klonierung Strategien (siehe Abbildung 1) 12. Die BBS ist 3 &#39;der pH-sensitive GFP-Reporters durch ein 13-Aminosäure Alanin / Prolin-Linker getrennt ist. Für Handel in dieser Veröffentlichung, die auf festen Proben basieren beschriebenen Studien, die pHGFP dient als ein Reporter der Gesamt getaggt GABAAR Untereinheit Protein-Ebene, so dass eine Normalisierung der Bgt markierten Rezeptor Bevölkerung insgesamt Rezeptor Bevölkerung. Dies minimiert Zelle zu Bgt Färbung Signalvariabilität von höheren oder niedrigeren Ausgangs Ausdruck der markierten Untereinheiten GABAAR resultierende Zell. Außerdem die pHGFP Tag ermöglicht eine einfache Identifizierung der Konstrukt exprimierenden Zellen für Live-oder Fest Imaging Experimenten.

Charakterisierung eines BBS tagged Konstrukt wichtigen Elemente wie die Bestimmung, ob das exprimierte Protein korrekt assembliert (insbesondere Rezeptoren von mehreren Untereinheiten zusammengesetzt), Verkehre auf der Zelloberfläche lokalisiert und geeignet. Hemmende Synapsen von GABA A-Rezeptor-Cluster, die Oberfläche mit der inhibitorischen Gerüstprotein Gephyrin colokalisieren und an präsynaptischen inhibitorischen Terminals, durch den vesikulären inhibitorischen Aminosäuretransporter, die GABA und Glycin in s...

Watch this Scientific Journal Video about Using an Î±-Bungarotoxin Binding Site Tag to Study GABA A Receptor Membrane Localization and Trafficking at JoVE.com

Using an &amp;#945;-Bungarotoxin Binding Site Tag to Study GABA A Receptor Membrane Localization and Trafficking

Hier zeigen wir die Verwendung von Fluoreszenzfarbstoff Alexa gekoppelt α-Bungarotoxin an GABA A-Rezeptor-Oberflächenlokalisierung und Endozytose in hippocampalen Neuronen zu messen. Durch die Verwendung von Konstrukten, die mit einem kurzen extrazellulären Tag, das α-Bungarotoxin, kann die Analyse der Plasma-Membran-Protein endozytischen Handel erreicht werden, bindet.

Mit Hilfe eines α-Bungarotoxin Binding Site Tag an GABA A-Rezeptor-Membranlokalisierung und Handel Studieren

It is increasingly evident that neurotransmitter receptors, including ionotropic GABA A receptors (GABAAR), exhibit highly dynamic trafficking and cell ...

using-an-bungarotoxin-binding-site-tag-to-study-gaba-receptor

Research

JoVE Journal

Neuroscience

Using an &#945;-Bungarotoxin Binding Site Tag to Study GABA A Receptor Membrane Localization and Trafficking

15.7K Aufrufe.  University of Pittsburgh School of Medicine.  Hier zeigen wir die Verwendung von Fluoreszenzfarbstoff Alexa gekoppelt α-Bungarotoxin an GABA A-Rezeptor-Oberflächenlokalisierung und Endozytose in hippocampalen Neuronen zu messen. Durch die Verwendung von Konstrukten, die mit einem kurzen extrazellulären Tag, das α-Bungarotoxin, kann die Analyse der Plasma-Membran-Protein endozytischen Handel erreicht werden, bindet. 

Serie: Using an &#945;-Bungarotoxin Binding Site Tag to Study GABA A Receptor Membrane Localization and Trafficking

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.

Quantitative Analyse der synaptischen Vesikel Pool Replenishment in Cultured Cerebellar Nervenzellen Granulat mit FM Dyes

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

Forschung

Neurowissenschaften

Using MazeSuite and Functional Near Infrared Spectroscopy to Study Learning in Spatial Navigation

MazeSuite is a complete toolset to prepare, present and analyze navigational and spatial experiments1. MazeSuite can be used to design and edit adapted virtual 3D environments, track a participants' behavioral performance within the virtual environment and synchronize with external devices for physiological and neuroimaging measures, including electroencephalogram and eye tracking.
Functional near-infrared spectroscopy (fNIR) is an optical brain imaging technique that enables continuous, noninvasive, and portable monitoring of changes in cerebral blood oxygenation related to human brain functions2-7. Over the last decade fNIR is used to effectively monitor cognitive tasks such as attention, working memory and problem solving7-11. fNIR can be implemented in the form of a wearable and minimally intrusive device; it has the capacity to monitor brain activity in ecologically valid environments. 
Cognitive functions assessed through task performance involve patterns of brain activation of the prefrontal cortex (PFC) that vary from the initial novel task performance, after practice and during retention12. Using positron emission tomography (PET), Van Horn and colleagues found that regional cerebral blood flow was activated in the right frontal lobe during the encoding (i.e., initial na&iuml;ve performance) of spatial navigation of virtual mazes while there was little to no activation of the frontal regions after practice and during retention tests. Furthermore, the effects of contextual interference, a learning phenomenon related to organization of practice, are evident when individuals acquire multiple tasks under different practice schedules13,14. High contextual interference (random practice schedule) is created when the tasks to be learned are presented in a non-sequential, unpredictable order. Low contextual interference (blocked practice schedule) is created when the tasks to be learned are presented in a predictable order.
Our goal here is twofold: first to illustrate the experimental protocol design process and the use of MazeSuite, and second, to demonstrate the setup and deployment of the fNIR brain activity monitoring system using Cognitive Optical Brain Imaging (COBI) Studio software15. To illustrate our goals, a subsample from a study is reported to show the use of both MazeSuite and COBI Studio in a single experiment. The study involves the assessment of cognitive activity of the PFC during the acquisition and learning of computer maze tasks for blocked and random orders. Two right-handed adults (one male, one female) performed 315 acquisition, 30 retention and 20 transfer trials across four days. Design, implementation, data acquisition and analysis phases of the study were explained with the intention to provide a guideline for future studies.

MazeSuite is a complete toolset to prepare, present and analyze navigational and spatial experiments. Functional near-infrared spectroscopy (fNIR) is an optical brain imaging technique that enables noninvasive and portable monitoring of cerebral blood oxygenation changes. This paper summarizes collective use of MazeSuite and fNIR within a cognitive processing learning paradigm.

Mit MazeSuite und Functional Near Infrared Spectroscopy man Lernen in Spatial Navigation

MazeSuite is a complete toolset to prepare, present and analyze navigational and spatial experiments1. MazeSuite can be used to design and edit adapted ...

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.

Imaging Receptor Insertion in die Plasmamembran pHluorin-Tag in der Grundschule Cultured Mäuseneuronen

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

Local Application of Drugs to Study Nicotinic Acetylcholine Receptor Function in Mouse Brain Slices

Tobacco use leads to numerous health problems, including cancer, heart disease, emphysema, and stroke. Addiction to cigarette smoking is a prevalent neuropsychiatric disorder that stems from the biophysical and cellular actions of nicotine on nicotinic acetylcholine receptors (nAChRs) throughout the central nervous system. Understanding the various nAChR subtypes that exist in brain areas relevant to nicotine addiction is a major priority.
Experiments that employ electrophysiology techniques such as whole-cell patch clamp or two-electrode voltage clamp recordings are useful for pharmacological characterization of nAChRs of interest. Cells expressing nAChRs, such as mammalian tissue culture cells or Xenopus laevis oocytes, are physically isolated and are therefore easily studied using the tools of modern pharmacology. Much progress has been made using these techniques, particularly when the target receptor was already known and ectopic expression was easily achieved. Often, however, it is necessary to study nAChRs in their native environment: in neurons within brain slices acutely harvested from laboratory mice or rats. For example, mice expressing "hypersensitive" nAChR subunits such as &alpha;4 L9&prime;A mice 1 and &alpha;6 L9&prime;S mice 2, allow for unambiguous identification of neurons based on their functional expression of a specific nAChR subunit. Although whole-cell patch clamp recordings from neurons in brain slices is routinely done by the skilled electrophysiologist, it is challenging to locally apply drugs such as acetylcholine or nicotine to the recorded cell within a brain slice. Dilution of drugs into the superfusate (bath application) is not rapidly reversible, and U-tube systems are not easily adapted to work with brain slices.
In this paper, we describe a method for rapidly applying nAChR-activating drugs to neurons recorded in adult mouse brain slices. Standard whole-cell recordings are made from neurons in slices, and a second micropipette filled with a drug of interest is maneuvered into position near the recorded cell. An injection of pressurized air or inert nitrogen into the drug-filled pipette causes a small amount of drug solution to be ejected from the pipette onto the recorded cell. Using this method, nAChR-mediated currents are able to be resolved with millisecond accuracy. Drug application times can easily be varied, and the drug-filled pipette can be retracted and replaced with a new pipette, allowing for concentration-response curves to be created for a single neuron. Although described in the context of nAChR neurobiology, this technique should be useful for studying many types of ligand-gated ion channels or receptors in neurons from brain slices.

In this paper, we describe a useful method to study ligand-gated ion channel function in neurons of acutely isolated brain slices. This method involves the use of a drug-filled micropipette for local application of drugs to neurons recorded using standard patch clamp techniques.

Lokale Anwendung von Medikamenten zur nikotinischen Acetylcholin-Rezeptor-Funktion in Maus Hirnschnitten Studie

Tobacco use leads to numerous health problems, including cancer, heart disease, emphysema, and stroke. Addiction to cigarette smoking is a prevalent ...

Fast Micro-iontophoresis of Glutamate and GABA: A Useful Tool to Investigate Synaptic Integration

One of the fundamental interests in neuroscience is to understand the integration of excitatory and inhibitory inputs along the very complex structure of the dendritic tree, which eventually leads to neuronal output of action potentials at the axon. The influence of diverse spatial and temporal parameters of specific synaptic input on neuronal output is currently under investigation, e.g. the distance-dependent attenuation of dendritic inputs, the location-dependent interaction of spatially segregated inputs, the influence of GABAergig inhibition on excitatory integration, linear and non-linear integration modes, and many more.
With fast micro-iontophoresis of glutamate and GABA it is possible to precisely investigate the spatial and temporal integration of glutamatergic excitation and GABAergic inhibition. Critical technical requirements are either a triggered fluorescent lamp, light-emitting diode (LED), or a two-photon scanning microscope to visualize dendritic branches without introducing significant photo-damage of the tissue. Furthermore, it is very important to have a micro-iontophoresis amplifier that allows for fast capacitance compensation of high resistance pipettes. Another crucial point is that no transmitter is involuntarily released by the pipette during the experiment.
Once established, this technique will give reliable and reproducible signals with a high neurotransmitter and location specificity. Compared to glutamate and GABA uncaging, fast iontophoresis allows using both transmitters at the same time but at very distant locations without limitation to the field of view. There are also advantages compared to focal electrical stimulation of axons: with micro-iontophoresis the location of the input site is definitely known and it is sure that only the neurotransmitter of interest is released. However it has to be considered that with micro-iontophoresis only the postsynapse is activated and presynaptic aspects of neurotransmitter release are not resolved. In this article we demonstrate how to set up micro-iontophoresis in brain slice experiments.

In this article we introduce fast micro-iontophoresis of neurotransmitters as a technique to investigate integration of postsynaptic signals with high spatial and temporal precision.

Schnelle Micro-Iontophorese von Glutamat und GABA: Ein nützliches Tool, um Synaptic Integration Untersuchen

One of the fundamental interests in neuroscience is to understand the integration of excitatory and inhibitory inputs along the very complex structure of ...

Membrane Potential Dye Imaging of Ventromedial Hypothalamus Neurons From Adult Mice to Study 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 increasing connective tissue and decreased neuronal viability that occur with age. Here, we describe a methodology for the dissociation of healthy hypothalamic neurons from adult-aged mice. The ability to study neurons from adult-aged mice allows the use of disease models that manifest at a later age and might be more developmentally accurate for certain studies. Fluorescence imaging of dissociated neurons can be used to study the activity of a population of neurons, as opposed to using electrophysiology to study a single neuron. This is particularly useful when studying a heterogeneous neuronal population in which the desired neuronal type is rare such as for hypothalamic glucose sensing neurons. We utilized membrane potential dye imaging of adult ventromedial hypothalamic neurons to study their responses to changes in extracellular glucose. Glucose sensing neurons are believed to play a role in central regulation of energy balance. The ability to study glucose sensing in adult rodents is particularly useful since the predominance of diseases related to dysfunctional energy balance (e.g.&#160;obesity) increase with age.

The activity of single neurons from adult-aged mice can be studied by dissociating neurons from specific brain regions and using fluorescent membrane potential dye imaging. By testing responses to changes in glucose, this technique can be used to study the glucose sensitivity of adult ventromedial hypothalamic neurons.

Membrane Potential Dye Imaging von Ventromedial Hypothalamus Neuronen aus erwachsenen Mäusen zu Glucose Sensing Studieren

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

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.

Hirnschnitt Biotinylierung: Eine<em&gt; Ex Vivo</em&gt; Ansatz zur Region spezifische Plasma Membrane Protein Handel Erwachsene Neuronen messen

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

Localization of Odorant Receptor Genes in Locust Antennae by RNA In Situ Hybridization

Insects have evolved sophisticated olfactory reception systems to sense exogenous chemical signals. These chemical signals are transduced by Olfactory Receptor Neurons (ORNs) housed in hair-like structures, called chemosensilla, of the antennae. On the ORNs&#39; membranes, Odorant Receptors (ORs) are believed to be involved in odor coding. Thus, being able to identify genes localized to the ORNs is necessary to recognize OR genes, and provides a fundamental basis for further functional in situ studies. The RNA expression levels of specific ORs in insect antennae are very low, and preserving insect tissue for histology is challenging. Thus, it is difficult to localize an OR to a specific type of sensilla using RNA in situ hybridization. In this paper, a detailed and highly effective RNA in situ hybridization protocol particularly for lowly expressed OR genes of insects, is introduced. In addition, a specific OR gene was identified by conducting double-color fluorescent in situ hybridization experiments using a co-expressing receptor gene, Orco, as a marker.

Localization of Odorant Receptor Genes in Locust Antennae by RNA In Situ Hybridization

This paper describes a detailed and highly effective RNA in situ hybridization protocol particularly for low-level expressed Odorant Receptor (OR) genes, as well as other genes, in insect antennae using digoxigenin (DIG)-labeled or biotin-labeled probes.

Lokalisierung von Odorant-Rezeptor-Genen in Locust-Antennen durch RNA<em&gt; In Situ</em&gt; Hybridisierung

Insects have evolved sophisticated olfactory reception systems to sense exogenous chemical signals. These chemical signals are transduced by Olfactory ...

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.

Live-Bilder von GLUT4 Protein Menschenhandel Maus primäre hypothalamische Neurone mit Dekonvolution Mikroskopie

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

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

Despite&#160;numerous studies that attempt to develop reliable animal models&#160;which reflecting the primary processes underlying neurodegeneration, very few have been widely accepted. Here, we propose&#160;a new procedure&#160;adapted from the well-known ex vivo brain slice technique, which offers a closer in vivo-like scenario than in vitro preparations, for investigating the early events triggering cell degeneration, as observed in Alzheimer&#39;s disease (AD). This variation consists of simple and easily reproducible steps, which enable preservation of the anatomical cytoarchitecture of the selected brain region and its local functionality in a physiological milieu. Different anatomical areas can be obtained from the same brain, providing the opportunity to perform multiple experiments with the treatments in question in a site-, dose-, and time-dependent manner. Potential limitations&#160;which could affect the outcomes related to this methodology are related to the conservation of the tissue, i.e., the maintenance of its anatomical integrity during the slicing and incubation steps and the section thickness, which can influence the biochemical and immunohistochemical analysis. This approach can be employed for different purposes, such as exploring molecular mechanisms involved in physiological or pathological conditions, drug screening, or dose-response assays. Finally, this protocol could also reduce the number of animals employed in behavioral studies. The application reported here has been recently described and tested for the first time on ex vivo rat brain slices containing the basal forebrain (BF), which is one of the cerebral regions primarily affected in AD. Specifically, it has been demonstrated that the administration of a toxic peptide derived from the C-terminus of acetylcholinesterase (AChE) could prompt an AD-like profile, triggering, along the antero-posterior axis of the BF, a differential expression of proteins altered in AD, such as the alpha7 nicotinic receptor (&#945;7-nAChR), phosphorylated Tau (p-Tau), and amyloid beta (A&#946;).

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

We present a method which can&#160;provide further insights into the early events underlying neurodegeneration and based on the established ex-vivo brain technique, combining the advantages of in vivo and in vitro experiments. Moreover, it represents a unique opportunity for direct comparison of treated and untreated group in the same anatomical plane.

Ein alternativer Ansatz zur primären Ereignissen in Neurodegeneration mit Ex Vivo Ratte Gehirnscheiben studieren

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