Samuel L. Pfaff ist ein Professor in der Genexpression Laboratories am Salk Institute for Biological Studies und ein Investigator in der Howard Hughes Medical Institute. Diese Arbeit wurde von der Christopher and Dana Reeve Foundation unterstützt. Joe Belcovson, Kent Schnoeker und Mike Sullivan in Multimedia-Ressourcen am Salk Institute unterstützte mit der Fotografie und Bearbeitung.

1. Bereiten künstlichen Liquor (aCSF) 1. Wir bereiten Sie zunächst einen 2 l einer 10-fach Bestand aCSF ohne Magnesium oder Calcium. Reagenzien in millimolaren aufgeführt. Katalog-Nummern beziehen sich auf Sigma / Aldrich. <table border="1" cellpadding="0"><tbody><tr><td colspan="4"> 2 Liter 10X aCSF (ohne Mg oder Ca) </td></tr><tr><td> Reagens </td><td> mM </td><td> g/2L </td><td> Katalog </td></tr><tr><td> KCl </td><td> 40 </td><td> 5,96 </td><td> P-9333 </td></tr><tr><td> NaCl </td><td> 1280 </td><td> 149,61 </td><td> S-7653 </td></tr><tr><td> NaHCO 3 </td><td> 210 </td><td> 35,28 </td><td> S-6297 </td></tr><tr><td> NaH 2 PO 4 </td><td> 5 </td><td> 1,38 </td><td> S-9638 </td></tr><tr><td> Glucose </td><td> 300 </td><td> 108,12 </td><td> D-9434 </td></tr><tr><td colspan="4"> Destilliertem Wasser auf 2L </td></tr></tbody></table> Außerdem bereiten wir 1M Lösungen von MgSO 4 und CaCl 2 in 50 mL Wasser, um Anpassungen in Molarität von Experiment zu Experiment zu ermöglichen und zu gewährleisten, das Kalzium in Lösung bleibt. <table border="1" cellpadding="0"><tbody><tr><td colspan="4"> 1M Calcium und Magnesium Stocks </td></tr><tr><td> Reagens </td><td> M </td><td> g/50mL </td><td> Katalog </td></tr><tr><td> CaCl 2 </td><td> 1 </td><td> 7,35 </td><td> C-5080 </td></tr><tr><td> MgSO 4 </td><td> 1 </td><td> 12,33 </td><td> M-5921 </td></tr></tbody></table> Die aCSF Lösung muss mit Carbogen (95% O2 / 5% CO2) vergast werden, um den pH-Wert vor Zugabe von Calcium oder Calcium wird Niederschlag geringer. <table border="1" cellpadding="0"><tbody><tr><td colspan="2"> 1 Liter aCSF </td></tr><tr><td> Reagens </td><td> Volumen </td></tr><tr><td> 10X aCSF </td><td> 100ml </td></tr><tr><td> 1M CaCl 2 </td><td> 1 mL (Sezieren) 2 ml (Aufnahme) </td></tr><tr><td> 1M MgSO 4 </td><td> 1 mL </td></tr><tr><td colspan="2"> Fügen Sie ~ 800 ml destilliertem Wasser, Gas mit Carbogen für 2 Minuten, bevor die Zugabe von Calcium </td></tr><tr><td colspan="2"> Add destilliertem Wasser auf 1L. </td></tr></tbody></table> Die Pumpen und Schläuche und seziert Gerichte sollten vor und nach Gebrauch abgespült werden. Zergliederung Während sezieren sollte 1mM Calcium aCSF kontinuierlich mit Carbogen begast werden. Die aCSF kann aus einer Flasche, die sezieren Gericht abgeschöpft werden und pumpte aus dem Sezieren Gericht auf die Flasche oder in den Abfall. Wir verwenden ein Elastomer (Sylgard, Dow Corning) beschichtet Gericht die Dissektion durchzuführen. Das Neugeborenen-Maus ist schnell mit einer scharfen Schere und einen Schnitt mit der Schere durch den ventralen Thorax und Abdomen gemacht enthauptet. Das Tier wird dann ausgeweidet. Die ausgenommene Maus ist mit aCSF gespült. Das Tier wird dann mit dem Sezieren Gericht mit Insekten Stifte durch die Vorderbeine und an der Basis des Schwanzes eingefügt merken. Die Wirbelsäule wird durch Ausführen einer ventralen Laminektomie entfernt. Die Wirbelsäule ist mit kleinen Zange gehalten und eine Klinge von kleinen Schere eingeführt wird unmittelbar dorsal der knöchernen Wirbelsäule. Die Lamina ist auf der einen Seite und dann die andere schneiden, während leichtes Anheben der knöchernen Wirbelsäule. Dies wird für die Länge der Wirbelsäule durchgeführt. Das Rückenmark wird durch Schneiden auf beiden Seiten entlang des Rückenmarks auf die Nervenwurzeln zu trennen und schneiden den Hirnhäuten umgeben das Rückenmark entfernt. Wir schneiden auf der linken und rechten Seite, dann schneiden wir die Meningen an der Rückenseite des Rückenmarks um sie zu befreien. Die isolierte Kabel wird dann an das Gericht in der Nähe des aCSF Einlass gute Sauerstoffversorgung zu gewährleisten, wenn zusätzliche Tiere seziert werden merken. Die isolierte Rückenmark ist dann eine Aufnahme Teller mit einem kleinen Löffel oder Spatel übertragen. Hier haben wir versorgen die Vorbereitung mit sauerstoffreichem 2mM Calcium aCSF. Das Rückenmark ist mit dem Elastomer beschichtet Schüssel und Mikromanipulatoren verwendet werden, um extrazelluläre, ganze Wurzel Saugelektroden in der Nähe der Wurzeln zu bewegen merken. Wenn die Spitze der Elektrode in der Nähe des freien root Ende ist, ist sanfte Saugwirkung angewendet an der Wurzel in die Saugelektrode ziehen. Dieser Vorgang kann wiederholt werden, um mehrere Wurzeln gleichzeitig aufgezeichnet werden. <img src="/files/ftp_upload/1660/1660fig1.jpg" alt="Abbildung 1" /> Abbildung 1. Enthauptung und Ausweiden. A. Schnell enthaupten der Maus mit einer scharfen Schere. Mehr oder weniger Beiträge aus dem Hirnstamm erreicht in Abhängigkeit von der Höhe der geschnitten werden. B. Legen Sie ein Blatt der Schere in die Öffnung der Brusthöhle von der Enthauptung erstellt. Öffnen Sie das ventrale Thorax und Abdomen an der Basis des Schwanzes. Entfernen Sie die Eingeweide und gründlich mit aCSF. <img src="/files/ftp_upload/1660/1660fig2.jpg" alt="Abbildung 2"/&gt; Abbildung 2. Die Entfernung der Wirbelsäule. A. Setzen Sie die linke Blatt der Schere in den Raum zwischen der Wirbelsäule und des Rückenmarks auf der rechten Seite des Rückenmarks und Durchtrennung der Knochen über ventral am Kabel. Dann legen Sie die richtige Klinge der Schere in den Raum zwischen der Wirbelsäule und des Rückenmarks auf der linken Seite des Rückenmarks und geschnitten. B. Wiederholen Sie diesen Vorgang unter sanftem Zug auf die Wirbelsäule. Achten Sie darauf, Punktion des Rückenmarks, indem Sie die Schere in einem flachen Winkel. <img src="/files/ftp_upload/1660/1660fig3.jpg" alt="Abbildung 3" /> Abbildung 3. Die Entfernung der Spinal Cord. A. Setzen Sie die linke Blatt der Schere in den Raum zwischen dem Rückenmark und die Knochen auf der rechten Seite des Rückenmarks und Durchtrennung der Wirbelsäule Wurzeln und Meningen über seitlich am Kabel. Dann legen Sie die richtige Klinge der Schere in den Raum zwischen dem Rückenmark und die Knochen auf der linken Seite des Rückenmarks und Durchtrennung der Wirbelsäule Wurzeln und Meningen Verlegung seitlich am Kabel. B. Schließlich heben die rostral Kabel und schneiden den Hirnhäuten Anschluss der Dorsalmark der Lamellen. Auch darauf achten, nicht zu durchstechen das Rückenmark, indem Sie die Schere in einem flachen Winkel. Schneiden Sie nicht die Wurzeln zu nahe an das Rückenmark.

<ol>
	<li>Myers, C. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cholinergic+input+is+required+during+embryonic+development+to+mediate+proper+assembly+of+spinal+locomotor+circuits.">Cholinergic input is required during embryonic development to mediate proper assembly of spinal locomotor circuits.</a> Neuron. 46, 37-49 (2005).</li><li>Goulding, M., Pfaff, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+circuits+that+generate+simple+rhythmic+behaviors+in+vertebrates.">Development of circuits that generate simple rhythmic behaviors in vertebrates.</a> Curr Opin Neurobiol. 15 (1), 14-20 (2005).</li><li>Gallarda, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Segregation+of+axial+motor+and+sensory+pathways+via+heterotypic+trans-axonal+signaling.">Segregation of axial motor and sensory pathways via heterotypic trans-axonal signaling.</a> Science. 320, (2008).</li><li>Gosgnach, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=V1+spinal+neurons+regulate+the+speed+of+vertebrate+locomotor+outputs.">V1 spinal neurons regulate the speed of vertebrate locomotor outputs.</a> Nature. 440 (7081), 215-219 (2006).</li><li>Lanuza, G. M., Gosgnach, S., Pierani, A., Jessell, T. M., Goulding, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetic+identification+of+spinal+interneurons+that+coordinate+left-right+locomotor+activity+necessary+for+walking+movements.">Genetic identification of spinal interneurons that coordinate left-right locomotor activity necessary for walking movements.</a> Neuron. 42 (3), 375-386 (2004).</li><li>Jiang, Z., Carlin, K. P., Brownstone, R. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+in+vitro+functionally+mature+mouse+spinal+cord+preparation+for+the+study+of+spinal+motor+networks.">An in vitro functionally mature mouse spinal cord preparation for the study of spinal motor networks.</a> Brain Res. 816 (2), 493-499 (1999).</li><li>Ziskind-Conhaim, L., Gao, B. X., Hinckley, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ethanol+dual+modulatory+actions+on+spontaneous+postsynaptic+currents+in+spinal+motoneurons.">Ethanol dual modulatory actions on spontaneous postsynaptic currents in spinal motoneurons.</a> J Neurophysiol. 89 (2), 806-813 (2003).</li><li>Tabak, J., Rinzel, J., O'Donovan, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+role+of+activity-dependent+network+depression+in+the+expression+and+self-regulation+of+spontaneous+activity+in+the+developing+spinal+cord.">The role of activity-dependent network depression in the expression and self-regulation of spontaneous activity in the developing spinal cord.</a> J Neurosci. 21 (22), 8966-8978 (2001).</li><li>Chub, N., Mentis, G. Z., O'Donovan, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chloride-sensitive+MEQ+fluorescence+in+chick+embryo+motoneurons+following+manipulations+of+chloride+and+during+spontaneous+network+activity.">Chloride-sensitive MEQ fluorescence in chick embryo motoneurons following manipulations of chloride and during spontaneous network activity.</a> J Neurophysiol. 95 (1), 323-330 (2006).</li></ol>

Tierpflege<br /&gt;<br /&gt; Experimente an Tieren wurden in Übereinstimmung mit den Richtlinien und Vorschriften her von The Salk Institute for Biological Studies AIACUC gesetzt durchgeführt.

Die isolierten neonatalen Rückenmark stellt eine gefügig Methode zur Untersuchung des Nervensystems Entwicklung1, 2. Im Lumbalmark der Neugeborenen-Nagetiere, kann central pattern Erzeugung Schaltung fiktiven Fortbewegung in Gegenwart von Neurotransmittern zu produzieren. Diese fiktive Lokomotion besteht aus rhythmischen Anstieg der Aktivität, Bursts, dass bei 0,2 bis 0,5 Hz erzeugt werden. Diese Ausbrüche sind so organisiert, links-rechts abwechselnd entlang der Länge des Kabels und der Beuger-Strecker Wechsel (ip...

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		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
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<tr>
<td>KCl</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>P-9333</td>
<td>&nbsp;</td>
<tr>
<td>NaCl	</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>S-7653</td>
<td>&nbsp;</td>
<tr>
<td>NaHCO3</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>S-6297</td>
<td>&nbsp;</td>
<tr>
<td>NaH2PO4</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>S-9638</td>
<td>&nbsp;</td>
<tr>
<td>Glucose</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>D-9434</td>
<td>&nbsp;</td>
<tr>
<td>CaCl2</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>C-5080</td>
<td>&nbsp;</td>
<tr>
<td>MgSO4</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>M-5921</td>
<td>&nbsp;</td>
<tr>
<td>Large Scissors</td>
<td>&nbsp;</td>
<td>Fine Science Tools</td>
<td>14070-12</td>
<td>&nbsp;</td>
<tr>
<td>Forceps</td>
<td>&nbsp;</td>
<td>Fine Science Tools</td>
<td>11050-10</td>
<td>&nbsp;</td>
<tr>
<td>Fine Scissors</td>
<td>&nbsp;</td>
<td>Fine Science Tools</td>
<td>15000-10</td>
<td>&nbsp;</td>
<tr>
<td>Insect pins</td>
<td>&nbsp;</td>
<td>Fine Science Tools</td>
<td>26002-10</td>
<td>&nbsp;</td>
<tr>
<td>Sylgard 184 (Dow-Corning)</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>1L volumetric flask</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
<tr>
<td>100mL volumetric flask</td>
<td>&nbsp;</td>
<td>&nbsp;</td>
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spinal cord electrophysiology

Das Neugeborenen-Maus Rückenmark ist ein Modell für die Untersuchung der Entwicklung von neuronalen Schaltungen und Fortbewegung. Wir zeigen das Rückenmark Dissektion und Vorbereitung der Aufnahme Bad künstlichen Liquor des Bewegungsapparates Studien verwendet. Nachdem seziert, kann das Rückenmark ventral Nervenwurzeln, um eine Aufnahme Elektrode angebracht werden, um die elektrophysiologische Signale des zentralen Muster erzeugen Schaltung innerhalb Lendenmark aufzunehmen.

Watch this Scientific Journal Video about Spinal Cord Electrophysiology at JoVE.com

Spinal Cord Electrophysiology

Eine Demonstration der Isolierung von Neugeborenen Maus Rückenmark für elektrophysiologische Untersuchungen.

Spinal Cord Elektrophysiologie

The neonatal mouse spinal cord is a model for studying the development of neural circuitries and locomotor movement. We demonstrate the spinal cord ...

Research

JoVE Journal

Biology

21.1K Aufrufe.  Howard Hughes Medical Institute and Gene Expression Laboratory. Eine Demonstration der Isolierung von Neugeborenen Maus Rückenmark für elektrophysiologische Untersuchungen.

Serie: Spinal Cord Electrophysiology

Applying Microfluidics to Electrophysiology

Microfluidics can be integrated with standard electrophysiology techniques to allow new experimental modalities.  Specifically, the motivation for the microfluidic brain slice device is discussed including how the device docks to standard perfusion chambers and the technique of passive pumping which is used to deliver boluses of neuromodulators to the brain slice.  By simplifying the device design, we are able to achieve a practical solution to the current unmet electrophysiology need of applying multiple neuromodulators across multiple regions of the brain slice.  This is achieved by substituting the standard coverglass substrate of the perfusion chamber with a thin microfluidic device bonded to the coverglass substrate.  This was then attached to the perfusion chamber and small holes connect the open-well of the perfusion chamber to the microfluidic channels buried within the microfluidic substrate.  These microfluidic channels are interfaced with ports drilled into the edge of the perfusion chamber to access and deliver stimulants.  This project represents how the field of microfluidics is transitioning away from proof-of concept device demonstrations and into practical solutions for unmet experimental and clinical needs.

Anwenden von Mikrofluidik zur Elektrophysiologie

Microfluidics can be integrated with standard electrophysiology techniques to allow new experimental modalities.  Specifically, the motivation for the ...

Forschung

Biologie

Preparation of Artificial Bilayers for Electrophysiology Experiments

Planar lipid bilayers, also called artificial lipid bilayers, allow you to study ion-conducting channels in a well-defined environment. These bilayers can be used for many different studies, such as the characterization of membrane-active peptides, the reconstitution of ion channels or investigations on how changes in lipid bilayer properties alter the function of bilayer-spanning channels.  Here, we show how to form a planar bilayer and how to isolate small patches from the bilayer, and in a second video  will also demonstrate a procedure for using gramicidin channels to determine changes in lipid bilayer elastic properties.   We also demonstrate the individual steps needed to prepare the bilayer chamber, the electrodes and how to test that the bilayer is suitable for single-channel measurements.

Planar lipid bilayers, also called artificial lipid bilayers, allow you to study ion-conducting channels in a well-defined environment. Here, we demonstrate the individual steps needed to prepare the bilayer chamber, the electrodes and how to test that the bilayer is suitable for single-channel measurements.

Herstellung künstlicher Doppelschichten für Elektrophysiologie Experimente

Planar lipid bilayers, also called artificial lipid bilayers, allow you to study ion-conducting channels in a well-defined environment. These bilayers can ...

Combining Peripheral Nerve Grafting and Matrix Modulation to Repair the Injured Rat Spinal Cord

Traumatic injury to the spinal cord (SCI) causes death of neurons, disruption of motor and sensory nerve fiber (axon) pathways and disruption of communication with the brain. One of the goals of our research is to promote axon regeneration to restore connectivity across the lesion site. To accomplish this we developed a peripheral nerve (PN) grafting technique where segments of sciatic nerve are either placed directly between the damaged ends of the spinal cord or are used to form a bridge across the lesion. There are several advantages to this approach compared to transplantation of other neural tissues; regenerating axons can be directed towards a specific target area, the number and source of regenerating axons is easily determined by tracing techniques, the graft can be used for electrophysiological experiments to measure functional recovery associated with axons in the graft, and it is possible to use an autologous nerve to reduce the possibility of graft rejection. In our lab we have performed both autologous (donor and recipient are the same animal) and heterologous (donor and recipient are different animals) grafts with comparable results. This approach has been used successfully in both acute and chronic injury situations. Regenerated axons that reach the distal end of the PN graft often fail to extend back into the spinal cord, so we use microinjections of chondroitinase to degrade inhibitory molecules associated with the scar tissue surrounding the area of SCI. At the same time we have found that providing exogenous growth and trophic molecules encourages longer distance axonal regrowth into the spinal cord. Several months after transplantation we perform a variety of anatomical, behavioral and electrophysiological tests to evaluate the recovery of function in our spinal cord injured animals. This experimental approach has been used successfully in several spinal cord injury models, at different levels of injury and in different species (mouse, rat and cat). Importantly, the peripheral nerve grafting approach is effective in promoting regeneration by acute and chronically injured neurons.

Traumatic injury to the spinal cord disrupts communication with the brain. To restore lost connectivity we utilize a peripheral nerve graft to provide a substratum for regenerating fibers in combination with neurotrophic factors and matrix-modulating enzymes to remove inhibitory molecules to promote long distance growth.

Die Kombination Peripheral Nerve Grafting und Matrix Modulation der Verletzte Rat Spinal Cord Repair

Traumatic injury to the spinal cord (SCI) causes death of neurons, disruption of motor and sensory nerve fiber (axon) pathways and disruption of ...

Semi-automated Optical Heartbeat Analysis of Small Hearts

We have developed a method for analyzing high speed optical recordings from Drosophila, zebrafish and embryonic mouse hearts (Fink, et. al., 2009). Our Semi-automatic Optical Heartbeat Analysis (SOHA) uses a novel movement detection algorithm that is able to detect cardiac movements associated with individual contractile and relaxation events. The program provides a host of physiologically relevant readouts including systolic and diastolic intervals, heart rate, as well as qualitative and quantitative measures of heartbeat arrhythmicity. The program also calculates heart diameter measurements during both diastole and systole from which fractional shortening and fractional area changes are calculated. Output is provided as a digital file compatible with most spreadsheet programs. Measurements are made for every heartbeat in a record increasing the statistical power of the output. We demonstrate each of the steps where user input is required and show the application of our methodology to the analysis of heart function in all three genetically tractable heart models.

We have developed a Semi-automated Optical Heartbeat Analysis method (SOHA) for analyzing high speed optical recordings from Drosophila, zebrafish and embryonic mouse hearts. We demonstrate the application of our methodology to the analysis of heart function in fruit fly and embryonic mouse hearts.

Semi-automatische optische Heartbeat-Analyse von kleinen Herzen

We have developed a method for analyzing high speed optical recordings from Drosophila, zebrafish and embryonic mouse hearts (Fink, et. al., 2009). Our ...

Assaying the Ability of Diffusible Signaling Molecules to Reorient Embryonic Spinal Commissural Axons

Dorsal commissural axons in the vertebrate spinal cord1 have been an invaluable model system in which to identify axon guidance signals. Here, we describe an in vitro assay, "the reorientation assay", that has been used extensively to study the effect of extrinsic and intrinsic signals on the orientation of commissural axons2. This assay was developed by numerous people in the laboratories of Jane Dodd, Thomas Jessell and Andrew Lumsden (see acknowledgements for more details) and versions of this assay were used to demonstrate the reorientation activities of key axon guidance molecules, including the BMP chemorepellent in the roof plate3,4 and the chemoattractive activities of Netrin15 and Sonic Hedgehog (Shh)6 in the floor plate in the spinal cord.
Explants comprising 2-3 segments of the dorsal two-thirds of spinal cord are dissected from embryonic day (E) 11 rats and cultured in three dimensional collagen gels7. E11 dorsal spinal explants contain newly born commissural neurons, which can be identified by their axonal expression of the glycoprotein, Tag18. Over the course of 30-40 hours in culture, the commissural axon trajectory is recapitulated in these dorsal explants with a time course similar to that seen in vivo. This axonal trajectory can be challenged by placing either test tissues or a COS cell aggregate expressing a candidate signaling molecule in contact with one of the lateral edges of the dorsal explant. Commissural axons extending in the vicinity of the appended tissue will grow under the influence of both the endogenous roof plate and signals from the ectopic lateral tissue. The degree to which commissural axons are reoriented under these circumstances can be quantified. Using this assay, it is possible both to examine the sufficiency of a particular signal to reorient commissural axons3,4 as well the necessity for this signal to direct the commissural trajectory9.

This assay assesses the ability of a signaling molecule, here Bone Morphogenetic Protein 7 (BMP7), to reorient commissural axons. An explant of embryonic dorsal spinal cord is cultured adjacent to an aggregate of COS cells secreting the candidate growth factors. Reoriented commissural axons growing within the explant are visualized by immunohistochemistry.

Testen der Fähigkeit des diffusiblen Signalmoleküle zu embryonalen Spinal kommissuralen Axone neu ausrichten

Dorsal commissural axons in the vertebrate spinal cord1 have been an invaluable model system in which to identify axon guidance signals.  Here, we ...

Exploring Arterial Smooth Muscle Kv7 Potassium Channel Function using Patch Clamp Electrophysiology and Pressure Myography

Contraction or relaxation of smooth muscle cells within the walls of resistance arteries determines the artery diameter and thereby controls flow of blood through the vessel and contributes to systemic blood pressure. The contraction process is regulated primarily by cytosolic calcium concentration ([Ca2+]cyt), which is in turn controlled by a variety of ion transporters and channels. Ion channels are common intermediates in signal transduction pathways activated by vasoactive hormones to effect vasoconstriction or vasodilation. And ion channels are often targeted by therapeutic agents either intentionally (e.g. calcium channel blockers used to induce vasodilation and lower blood pressure) or unintentionally (e.g. to induce unwanted cardiovascular side effects).
Kv7 (KCNQ) voltage-activated potassium channels have recently been implicated as important physiological and therapeutic targets for regulation of smooth muscle contraction. To elucidate the specific roles of Kv7 channels in both physiological signal transduction and in the actions of therapeutic agents, we need to study how their activity is modulated at the cellular level as well as evaluate their contribution in the context of the intact artery.
The rat mesenteric arteries provide a useful model system. The arteries can be easily dissected, cleaned of connective tissue, and used to prepare isolated arterial myocytes for patch clamp electrophysiology, or cannulated and pressurized for measurements of vasoconstrictor/vasodilator responses under relatively physiological conditions. Here we describe the methods used for both types of measurements and provide some examples of how the experimental design can be integrated to provide a clearer understanding of the roles of these ion channels in the regulation of vascular tone.

Measurements of Kv7 (KCNQ) potassium channel activity in isolated arterial myocytes (using patch clamp electrophysiological techniques) in parallel with measurements of constrictor/dilator responses (using pressure myography) can reveal important information about the roles of Kv7 channels in vascular smooth muscle physiology and pharmacology.

Exploring arteriellen glatten Muskelzellen KV7 Kalium Kanal Funktion mit Patch-Clamp-Elektrophysiologie und Druck Myographie

Contraction  or relaxation of smooth muscle cells within the walls of resistance arteries  determines the artery diameter and thereby controls flow of ...

Giant Liposome Preparation for Imaging and Patch-Clamp Electrophysiology

The reconstitution of ion channels into chemically defined lipid membranes for electrophysiological recording has been a powerful technique to identify and explore the function of these important proteins. However, classical preparations, such as planar bilayers, limit the manipulations and experiments that can be performed on the reconstituted channel and its membrane environment. The more cell-like structure of giant liposomes permits traditional patch-clamp experiments without sacrificing control of the lipid environment.
Electroformation is an efficient mean to produce giant liposomes &gt;10 &mu;m in diameter which relies on the application of alternating voltage to a thin, ordered lipid film deposited on an electrode surface. However, since the classical protocol calls for the lipids to be deposited from organic solvents, it is not compatible with less robust membrane proteins like ion channels and must be modified. Recently, protocols have been developed to electroform giant liposomes from partially dehydrated small liposomes, which we have adapted to protein-containing liposomes in our laboratory.
We present here the background, equipment, techniques, and pitfalls of electroformation of giant liposomes from small liposome dispersions. We begin with the classic protocol, which should be mastered first before attempting the more challenging protocols that follow. We demonstrate the process of controlled partial dehydration of small liposomes using vapor equilibrium with saturated salt solutions. Finally, we demonstrate the process of electroformation itself. We will describe simple, inexpensive equipment that can be made in-house to produce high-quality liposomes, and describe visual inspection of the preparation at each stage to ensure the best results.

Reconstituting functional membrane proteins into giant liposomes of defined composition is a powerful approach when combined with patch-clamp electrophysiology. However, conventional giant liposome production may be incompatible with protein stability. We describe protocols for producing giant liposomes from pure lipids or small liposomes containing ion channels.

Riesen-Liposomen-Herstellung für Imaging und Patch-Clamp-Elektrophysiologie

The reconstitution of ion channels into chemically defined lipid membranes for electrophysiological recording has been a powerful technique to identify ...

Introduction to Solid Supported Membrane Based Electrophysiology

The electrophysiological method we present is based on a solid supported membrane (SSM) composed of an octadecanethiol layer chemisorbed on a gold coated sensor chip and a phosphatidylcholine monolayer on top. This assembly is mounted into a cuvette system containing the reference electrode, a chlorinated silver wire.
After adsorption of membrane fragments or proteoliposomes containing the membrane protein of interest, a fast solution exchange is used to induce the transport activity of the membrane protein. In the single solution exchange protocol two solutions, one non-activating and one activating solution, are needed. The flow is controlled by pressurized air and a valve and tubing system within a faraday cage.
The kinetics of the electrogenic transport activity is obtained via capacitive coupling between the SSM and the proteoliposomes or membrane fragments. The method, therefore, yields only transient currents. The peak current represents the stationary transport activity. The time dependent transporter currents can be reconstructed by circuit analysis.
This method is especially suited for prokaryotic transporters or eukaryotic transporters from intracellular membranes, which cannot be investigated by patch clamp or voltage clamp methods.

Here we present an electrophysiological method based on solid supported membranes with focus on its applications for the characterization of electrogenic membrane transporters.

Einführung in die Festkörperphysik Unterstützte Membrane Basierend Elektrophysiologie

The electrophysiological method we present is based on a solid supported membrane (SSM) composed of an octadecanethiol layer chemisorbed on a gold coated ...

In Vivo SiRNA Transfection and Gene Knockdown in Spinal Cord via Rapid Noninvasive Lumbar Intrathecal Injections in Mice

This report describes a step-by-step guide to the technique of acute intrathecal needle injections in a noninvasive manner, i.e. independent of catheter implantation. The technical limitation of this surgical technique lies in the finesse of the hands. The injection is rapid, especially for a trained experimenter, and since tissue disruption with this technique is minimal, repeated injections are possible; moreover immune reaction to foreign tools (e.g. catheter) does not occur, thereby giving a better and more specific read out of spinal cord modulation. Since the application of the substance is largely limited to the target region of the spinal cord, drugs do not need to be applied in large dosages, and more importantly unwanted effects on other tissue, as observed with a systemic delivery, could be circumvented1,2. Moreover, we combine this technique with in vivo transfection of nucleic acid with the help of polyethylenimine (PEI) reagent3, which provides tremendous versatility for studying spinal functions via delivery of pharmacological agents as well as gene, RNA, and protein modulators.

In Vivo SiRNA Transfection and Gene Knockdown in Spinal Cord via Rapid Noninvasive Lumbar Intrathecal Injections in Mice

This report describes a simple and rapid technique of intrathecal needle puncture for a localized transfection of siRNA in the lumbar spinal cord in mouse under short lasting light anesthesia.

In vivo siRNA-Transfektion und Gene Knockdown im Rückenmark über Rapid-Nichtinvasive Lendenwirbel intrathekale Injektionen in Mäuse

This report describes a step-by-step guide to the technique of acute intrathecal needle injections in a noninvasive manner, i.e. independent of catheter ...

Cystometric and External Urethral Sphincter Measurements in Awake Rats with Implanted Catheter and Electrodes Allowing for Repeated Measurements

Lower urinary tract function is mainly assessed by means of cystometric bladder function analysis in rodents. Conventional cystometries are usually performed as terminal analysis under urethane anesthesia. It is well known that anesthetic drugs can influence bladder function. Hence, the aim of this technique is to perform cystometric measurements of the urinary bladder and external urethral sphincter in lightly restrained awake rats. For this purpose, a bladder catheter is implanted into the bladder dome. Subsequently, two electrodes are implanted bilateral to the external urethral sphincter and a ground electrode is sutured to a non-responsive skeletal muscle. The bladder catheter and the three electrodes are finally tunneled subcutaneously to the neck region and affixed to a harness. With this technique, the lower urinary tract can be measured at multiple time points in the same animal to assess lower urinary tract function. The main application of this technique is the follow-up of simultaneous urinary bladder and external urethral sphincter function in awake healthy rats and after induction of a disease or injury. Moreover, subsequent lower urinary tract monitoring can be performed during evaluation of the disease/injury and to monitor treatment efficacy.

This protocol first describes the surgical procedure of the permanent implantation of a urinary bladder catheter combined with external urethral sphincter electrodes, and second, the measurement of the function of the urinary bladder and external urethral sphincter in implanted awake animals.

Zystometrischen und externen urethralen Sphincter Messungen in wach Ratten mit implantierten Katheter und Elektroden für wiederholte Messungen

Lower urinary tract function is mainly assessed by means of cystometric bladder function analysis in rodents. Conventional cystometries are usually ...