Name: preparation of acute spinal cord slices for whole-cell patch-clamp recording in substantia gelatinosa neurons
Uploaded: 2019-01-18T12:30:00
Description: Watch this Scientific Journal Video about Preparation of Acute Spinal Cord Slices for Whole-cell Patch-clamp Recording in Substantia Gelatinosa Neurons at JoVE.com

This work was supported by grants from the National Natural Science Foundation of China (No. 81560198, 31660289).

All experimental protocols described were approved by the Animal Ethics Committee of Nanchang University (Nanchang, PR China, Ethical No.2017-010). All efforts were made to minimize the stress and pain of the experimental animals. The electrophysiological recordings performed here were carried out at room temperature (RT, 22&#8211;25 &#176;C).
1. Animals
<ol>
	<li>Use Sprague-Dawley rats (3&#8211;5 weeks old) of either sex. House the animals under a 12 h light-dark cycle and give them ad...

<ol>
	<li>Todd, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neuronal+circuitry+for+pain+processing+in+the+dorsal+horn.">Neuronal circuitry for pain processing in the dorsal horn.</a> Nature Reviews Neuroscience. 11 (12), 823-836 (2010).</li><li>Yoshimura, M., Nishi, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Blind+patch-clamp+recordings+from+substantia+gelatinosa+neurons+in+adult+rat+spinal+cord+slices:+pharmacological+properties+of+synaptic+currents.">Blind patch-clamp recordings from substantia gelatinosa neurons in adult rat spinal cord slices: pharmacological properties of synaptic currents.</a> Neuroscience. 53 (2), 519-526 (1993).</li><li>Maxwell, D. J., Belle, M. 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Y., Hughes, D. I., Riddell, J. S., Todd, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Populations+of+inhibitory+and+excitatory+interneurons+in+lamina+II+of+the+adult+rat+spinal+dorsal+horn+revealed+by+a+combined+electrophysiological+and+anatomical+approach.">Populations of inhibitory and excitatory interneurons in lamina II of the adult rat spinal dorsal horn revealed by a combined electrophysiological and anatomical approach.</a> Pain. 151 (2), 475-488 (2010).</li><li>Yin, H., Park, S. A., Han, S. K., Park, S. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+5-hydroxytryptamine+on+substantia+gelatinosa+neurons+of+the+trigeminal+subnucleus+caudalis+in+immature+mice.">Effects of 5-hydroxytryptamine on substantia gelatinosa neurons of the trigeminal subnucleus caudalis in immature mice.</a> Brain Research. 1368, 91-101 (2011).</li><li>Hu, T., 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=Lidocaine+Inhibits+HCN+Currents+in+Rat+Spinal+Substantia+Gelatinosa+Neurons.">Lidocaine Inhibits HCN Currents in Rat Spinal Substantia Gelatinosa Neurons.</a> Anesthesia and Analgesia. 122 (4), 1048-1059 (2016).</li><li>Peng, H. Z., Ma, L. X., Lv, M. H., Hu, T., Liu, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Minocycline+enhances+inhibitory+transmission+to+substantia+gelatinosa+neurons+of+the+rat+spinal+dorsal+horn.">Minocycline enhances inhibitory transmission to substantia gelatinosa neurons of the rat spinal dorsal horn.</a> Neuroscience. 319, 183-193 (2016).</li><li>Peng, S. 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H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Methods+for+whole-cell+recording+from+visually+preselected+neurons+of+perirhinal+cortex+in+brain+slices+from+young+and+aging+rats.">Methods for whole-cell recording from visually preselected neurons of perirhinal cortex in brain slices from young and aging rats.</a> Journal of Neuroscience Methods. 86 (1), 35-54 (1998).</li><li>Rothman, S. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+neurotoxicity+of+excitatory+amino+acids+is+produced+by+passive+chloride+influx.">The neurotoxicity of excitatory amino acids is produced by passive chloride influx.</a> The Journal of Neuroscience. 5 (6), 1483-1489 (1985).</li><li>Rice, M. 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This protocol details the steps for preparing spinal cord slices, which we have used successfully when performing whole-cell patch-clamp experiments on SG neurons18,19,20,21. By implementing this method, we recently reported that minocycline, a second generation of tetracycline, could markedly enhance inhibitory synaptic transmission through a presynaptic mechanism in SG neurons<sup class="xref...

The substantia gelatinosa (SG, lamina II of the spinal dorsal horn) is an indisputably important relay center for transmitting and regulating sensory information. It is composed of excitatory and inhibitory interneurons, which receive inputs from the primary afferent fibers, local interneurons, and the endogenous descending inhibitory system1. In recent decades, the development of acute spinal cord slice preparation and the advent of whole-cell patch-clamp recording have enabled various studies on the intrinsic electrophysiological and morphological properties of SG neurons2,3,4 as well as studies of the local circuitry in SG5,6. In addition, by using the in vitro spinal cord slice preparation, researchers can interpret the changes in neuronal excitabilities7,8, the function of ion channels9,10, and synaptic activities11,12 under various pathological conditions. These studies have deepened our understanding of the role that SG neurons play in the development and maintenance of chronic pain and neuropathic itch.
Essentially, the key prerequisite to achieve a clear visualization of neuronal soma and ideal whole-cell patching using acute spinal cord slices is to ensure the excellent quality of slices so healthy and patchable neurons can be obtained. However, preparing spinal cord slices involves several steps, such as performing a ventral laminectomy and removing the pia-arachnoid membrane, which may be obstacles in obtaining healthy slices. Although it is not easy to prepare spinal cord slices, performing recordings in vitro on spinal cord slices has several advantages. Compared to cell culture preparations, spinal cord slices can partially preserve inherent synaptic connections that are in a physiologically relevant condition. In addition, whole-cell patch-clamp recording using spinal cord slices could be combined with other techniques, such as double patch clamp13,14, morphological studies15,16 and single-cell RT-PCR17. Therefore, this technique provides more information on characterizing the anatomical and genetic diversities within a specific region and allows for investigation of the composition of local circuitry.
Here, we provide a basic and detailed description of our method for preparing acute spinal cord slices and acquiring whole-cell patch-clamp recordings from SG neurons.

<table>
	<tbody>
		<tr>
			<td>NaCl</td>
			<td>Sigma</td>
			<td>S7653</td>
			<td>Used for the preparation of ACSF and PBS</td>
		</tr>
		<tr>
			<td>KCl</td>
			<td>Sigma</td>
			<td>60130</td>
			<td>Used for the preparation of ACSF, sucrose-ACSF, and K+-based intracellular solution</td>
		</tr>
		<tr>
			<td>NaH2PO4&#183;2H2O</td>
			<td>Sigma</td>
			<td>71500</td>
			<td>Used for the preparation of ACSF, sucrose-ACSF and PBS</td>
		</tr>
		<tr>
			<td>CaCl2&#183;2H2O</td>
			<td>Sigma</td>
			<td>C5080</td>
			<td>Used for the preparation of ACSF and sucrose-ACSF</td>
		</tr>
		<tr>
			<td>MgCl2&#183;6H2O</td>
			<td>Sigma</td>
			<td>M2670</td>
			<td>Used for the preparation of ACSF and sucrose-ACSF</td>
		</tr>
		<tr>
			<td>NaHCO3</td>
			<td>Sigma</td>
			<td>S5761</td>
			<td>Used for the preparation of ACSF and sucrose-ACSF</td>
		</tr>
		<tr>
			<td>D-Glucose</td>
			<td>Sigma</td>
			<td>G7021</td>
			<td>Used for the preparation of ACSF</td>
		</tr>
		<tr>
			<td>Ascorbic acid</td>
			<td>Sigma</td>
			<td>P5280</td>
			<td>Used for the preparation of ACSF and sucrose-ACSF</td>
		</tr>
		<tr>
			<td>Sodium pyruvate</td>
			<td>Sigma</td>
			<td>A7631</td>
			<td>Used for the preparation of ACSF and sucrose-ACSF</td>
		</tr>
		<tr>
			<td>Sucrose</td>
			<td>Sigma</td>
			<td>S7903</td>
			<td>Used for the preparation of sucrose-ACSF</td>
		</tr>
		<tr>
			<td>K-gluconate</td>
			<td>Wako</td>
			<td>169-11835</td>
			<td>Used for the preparation of K+-based intracellular solution</td>
		</tr>
		<tr>
			<td>Na2-Phosphocreatine</td>
			<td>Sigma</td>
			<td>P1937</td>
			<td>Used for the preparation of intracellular solution</td>
		</tr>
		<tr>
			<td>EGTA</td>
			<td>Sigma</td>
			<td>E3889</td>
			<td>Used for the preparation of intracellular solution</td>
		</tr>
		<tr>
			<td>HEPES</td>
			<td>Sigma</td>
			<td>H4034</td>
			<td>Used for the preparation of intracellular solution</td>
		</tr>
		<tr>
			<td>Mg-ATP</td>
			<td>Sigma</td>
			<td>A9187</td>
			<td>Used for the preparation of intracellular solution</td>
		</tr>
		<tr>
			<td>Li-GTP</td>
			<td>Sigma</td>
			<td>G5884</td>
			<td>Used for the preparation of intracellular solution</td>
		</tr>
		<tr>
			<td>CsMeSO4</td>
			<td>Sigma</td>
			<td>C1426</td>
			<td>Used for the preparation of Cs+-based intracellular solution</td>
		</tr>
		<tr>
			<td>CsCl</td>
			<td>Sigma</td>
			<td>C3011</td>
			<td>Used for the preparation of Cs+-based intracellular solution</td>
		</tr>
		<tr>
			<td>TEA-Cl</td>
			<td>Sigma</td>
			<td>T2265</td>
			<td>Used for the preparation of Cs+-based intracellular solution</td>
		</tr>
		<tr>
			<td>Neurobiotin 488</td>
			<td>Vector</td>
			<td>SP-1145</td>
			<td>0.05% neurobiotin 488 could be used for morphological studies</td>
		</tr>
		<tr>
			<td>Agar</td>
			<td>Sigma</td>
			<td>A7002</td>
			<td>3% agar block was used in our protocol</td>
		</tr>
		<tr>
			<td>Paraformaldehyde</td>
			<td>Sigma</td>
			<td>P6148</td>
			<td>4% paraformaldehyde was used for immunohistochemical processing</td>
		</tr>
		<tr>
			<td>Na2HPO4</td>
			<td>Hengxing Chemical Reagents</td>
			<td></td>
			<td>Used for the preparation of PBS</td>
		</tr>
		<tr>
			<td>Mount Coverslipping Medium</td>
			<td>Polyscience</td>
			<td>18606</td>
			<td></td>
		</tr>
		<tr>
			<td>Urethan</td>
			<td>National Institute for Food and Drug Control</td>
			<td>30191228</td>
			<td>1.5 g/kg, i.p.</td>
		</tr>
		<tr>
			<td>Borosilicate glass capillaries</td>
			<td>World Precision Instruments</td>
			<td>TW150F-4</td>
			<td>1.5 mm OD, 1.12 mm ID</td>
		</tr>
		<tr>
			<td>Micropipette puller</td>
			<td>Sutter Instrument</td>
			<td>P-97</td>
			<td>Used for the preparation of micropipettes</td>
		</tr>
		<tr>
			<td>Vibratome</td>
			<td>Leica</td>
			<td>VT1000S</td>
			<td></td>
		</tr>
		<tr>
			<td>Vibration isolation table</td>
			<td>Technical Manufacturing Corporation</td>
			<td>63544</td>
			<td></td>
		</tr>
		<tr>
			<td>Infrared CCD camera</td>
			<td>Dage-MIT</td>
			<td>IR-1000</td>
			<td></td>
		</tr>
		<tr>
			<td>Patch-clamp amplifier</td>
			<td>HEKA</td>
			<td>EPC-10</td>
			<td></td>
		</tr>
		<tr>
			<td>Micromanipulator</td>
			<td>Sutter Instrument</td>
			<td>MP-285</td>
			<td></td>
		</tr>
		<tr>
			<td>X-Y stage</td>
			<td>Burleigh</td>
			<td>GIBRALTAR X-Y</td>
			<td></td>
		</tr>
		<tr>
			<td>Upright microscope</td>
			<td>Olympus</td>
			<td>BX51WI</td>
			<td></td>
		</tr>
		<tr>
			<td>Osmometer</td>
			<td>Advanced</td>
			<td>FISKE 210</td>
			<td></td>
		</tr>
		<tr>
			<td>PH meter</td>
			<td>Mettler Toledo</td>
			<td>FE20</td>
			<td></td>
		</tr>
		<tr>
			<td>Confocol microscope</td>
			<td>Zeiss</td>
			<td>LSM 700</td>
			<td></td>
		</tr>
	</tbody>
</table>

preparation of acute spinal cord slices for whole-cell patch-clamp recording in substantia gelatinosa neurons

Recent whole-cell patch-clamp studies from substantia gelatinosa (SG) neurons have provided a large body of information about the spinal mechanisms underlying sensory transmission, nociceptive regulation, and chronic pain or itch development. Implementations of electrophysiological recordings together with morphological studies based on the utility of acute spinal cord slices have further improved our understanding of neuronal properties and the composition of local circuitry in SG. Here, we present a detailed and practical guide for the preparation of spinal cord slices and show representative whole-cell recording and morphological results. This protocol permits ideal neuronal preservation and can mimic in vivo conditions to a certain extent. In summary, the ability to obtain an in vitro preparation of spinal cord slices enables stable current- and voltage-clamp recordings and could thus facilitate detailed investigations into the intrinsic membrane properties, local circuitry and neuronal structure using diverse experimental approaches.

Acute spinal cord slices were prepared according to the diagram shown in Figure 1. After slicing and recovery, a spinal cord slice was transferred to the recording chamber. Healthy neurons were identified based on soma appearance using IR-DIC microscopy. Next, the action potentials of SG neurons were elicited by a series of depolarizing current pulses (1 s duration) when neurons were held at RMP. As shown in Figure 2, the firing ...

Watch this Scientific Journal Video about Preparation of Acute Spinal Cord Slices for Whole-cell Patch-clamp Recording in Substantia Gelatinosa Neurons at JoVE.com

Preparation of Acute Spinal Cord Slices for Whole-cell Patch-clamp Recording in Substantia Gelatinosa Neurons

Here, we describe the essential steps for whole-cell patch-clamp recordings made from substantia gelatinosa (SG) neurons in the in vitro spinal cord slice. This method allows the intrinsic membrane properties, synaptic transmission and morphological characterization of SG neurons to be studied.

Recent whole-cell patch-clamp studies from substantia gelatinosa (SG) neurons have provided a large body of information about the spinal mechanisms ...

This method can help clarify the spinal mechanisms underlying sensory transmission, nociceptive regulation and chronic pain or ache development The main advantage of this technique is that it can permit ideal neuronal preservation and it can mimic in-vivo conditions to a certain extent. Start by pulling recording electrodes from borosilicate glass microcapillaries using a capillary puller. Then, fill a mold with molten agar to prepare a 1.2 centimeter by 1.5 centimeter by 2.0 centimeter agar block.Trim the block to have a central channel if planning transverse sections. Or a channel flesh with the edge of the block for parasagittal sections. Prior to transcardial profusion and spinal cord extraction, prepare 500 milliliters of sucrose based ACSF.Cool the solution to ice cold and equilibrate with 95%O2 and 5%CO2. Cool all the dissection tools on ice. Make a longitudinal five centimeter incision on the back skin from caudal to rostral.Then, cut through the rib cage between the spine and ribs on either side. Use scissors to made a cut at the caudal end of the spine. Then cut away the surrounding tissues and quickly isolate the lumbosacral segment of the spine.Transfer the lumbosacral segment to a glass dish containing ice cold sucrose based ACSF. With the ventral side upward, use fine scissors to cut through the vertebral pedicle bilaterally and expose the spinal cord carefully. Isolate a two centimeter long section of spinal cord with the lumbosacral enlargement and transfer the spinal section into another glass dish filled with cold sucrose ACSF.Work under a dissection microscope to remove the meninges and the pia arachnoid membrane. Cut all the ventral and dorsal roots away as quickly as possible. Take care to avoid the injuring to the spinal cord, especially the dorsal horn when removing the meninges and the spinal roots.Place the spinal cord on the previously trimmed agar block. To prepare transverse slices, attach the ventral side of the spinal cord to the agar with the dorsal side toward the blade. To prepare parasagittal slices, attach the ventral side with superglue to the agar in a vertical direction.Then, mount the agar block to a platform of a vibratome with superglue. And prepare 300 to 500 micron transverse or parasagittal slices with an advanced speed of 0.025 millimeters per second and a vibration frequency of 80 Hertz. The spinal cord should be sliced dorso-ventrally.For the best results, the slice should be prepared within 15 to 20 minutes. The thickness of the spinal slice should be no more than 600 microns to satisfy cell visibility. Use a plastic trimmed pipette to transfer the slices onto nylon mesh in a storage chamber containing continuously oxygenated ACSF at 32 degrees Celsius.To conduct whole-cell patch clamp recordings from substantia gelatinosa or SG neurons, use potassium ion based intracellular solutions for recording while applying caesium cation based solution only for the recording of inhibitory post-synaptic currents. Gently move the spinal cord slice to the recording chamber. And then stabilize it firmly with a U shaped platinum wire with nylon threads for optimal slice stability.Steadily profuse the slice with bubbled ACSF at room temperature and set the profusion rate at two to four milliliters per minute to achieve sufficient oxygenation. Then, using a low resolution microscope lens, identify the region of SG neurons as a translucent band. Choose a healthy neuron, characterized by a three dimensional shape with a bright and smooth membrane as the target cell using the high resolution objective and adjust it to the center of the video monitor screen.Fill a micro pipette with an appropriate volume of potassium ion based or caesium ion based intracellular solution. Then insert the micro-pipette into the electrode holder and ensure that the intracellular solution is contacting the silver wire inside the holder. Bring the micro pipette into focus and use the micromanipulator to immerse it into the ACSF.Apply a mild positive pressure to force away any dirt and debris. Gradually move the micro pipette towards the targeted neuron. Once the pipette approaches the neuron and a very small dimple forms on the neuronal membrane, release the positive pressure to form a gigaseal.Alter the holding potential to minus 70 millivolts, which is close to the physiological resting membrane potential of a cell. Then, apply a transient and gentle suction to the micro pipette to rupture the membrane and create a good whole-cell configuration. Record firing properties by testing the firing pattern of each neuron in current clamp with a series of one second depolarizing current pulses of 25 to 150 picoamps with 25 picoamp increments at resting membrane potential.To record somatic subthreshold currents, hold the membrane potential at minus 50 millivolts in voltage clamp mode then apply a series of hyperpolarising voltage pulses of one second duration from minus 60 millivolts to minus 120 millivolts with a 10 millivolt decrement. Record excitatory post-synaptic currents with the potassium ion based intracellular solution in voltage clamp mode at a holding potential of minus 70 millivolts. Record IPSC's using caesium ion based intracellular solution for recording IPSC's.After holding the membrane potential at minus 70 millivolts for approximately five minutes, gradually change the holding potential to zero millivolts. Wait a few minutes for stabilization and then start to record the IPSC events. Firing patterns determined by injecting a series of one second depolarizing current pulses into an SG neuron at resting membrane potential may be classified as tonic-firing, delayed-firing, gap-firing, initial-burst, phasic-bursting, single-spike and reluctant-firing.This image shows the evoking protocol for subthreshold currents in voltage clamp. These representative traces show the response to hyperpolarizing current injection classified as IH, IA and IT.This is a representative trace of SEPSC's recorded from SG neurons at minus 70 millivolts in the absence and presence of 50 micromolar APV and 20 micromolar CNQX. This trace shows the recorded SEPC's before the addition of APV and CNQX on an expanded timescale.Following this procedure are the methods like paired patch clamp recordings or optogenetics can be performed to answer additional questions like characterizing specific neuronal microcircuits in substantia gelatinosa.

preparation-acute-spinal-cord-slices-for-whole-cell-patch-clamp

Research

JoVE Journal

Neuroscience

Electrophysiological and Morphological Characterization of Neuronal Microcircuits in Acute Brain Slices Using Paired Patch-Clamp Recordings

The combination of patch clamp recordings from two (or more) synaptically coupled neurons (paired recordings) in acute brain slice preparations with simultaneous intracellular biocytin filling allows a correlated analysis of their structural and functional properties. With this method it is possible to identify and characterize both pre- and postsynaptic neurons by their morphology and electrophysiological response pattern. Paired recordings allow studying the connectivity patterns between these neurons as well as the properties of both chemical and electrical synaptic transmission. Here, we give a step-by-step description of the procedures required to obtain reliable paired recordings together with an optimal recovery of the neuron morphology. We will describe how pairs of neurons connected via chemical synapses or gap junctions are identified in brain slice preparations. We will outline how neurons are reconstructed to obtain their 3D morphology of the dendritic and axonal domain and how synaptic contacts are identified and localized. We will also discuss the caveats and limitations of the paired recording technique, in particular those associated with dendritic and axonal truncations during the preparation of brain slices because these strongly affect connectivity estimates. However, because of the versatility of the paired recording approach it will remain a valuable tool in characterizing different aspects of synaptic transmission at identified neuronal microcircuits in the brain.

Patch-clamp recordings and simultaneous intracellular biocytin filling of synaptically coupled neurons in acute brain slices allow a correlated analysis of their structural and functional properties. The aim of this protocol is to describe the essential technical steps of electrophysiological recording from neuronal microcircuits and their subsequent morphological analysis.

The combination of patch clamp recordings from two (or more) synaptically coupled neurons (paired recordings) in acute brain slice preparations with ...

Whole-cell Patch-clamp Recordings in Brain Slices

Whole-cell patch-clamp recording is an electrophysiological technique that allows the study of the&#160;electrical properties of a substantial part of the neuron. In this configuration, the micropipette is in tight contact with the cell membrane, which prevents current leakage and thereby provides more accurate ionic current measurements than the previously used intracellular sharp electrode recording method. Classically, whole-cell recording can be performed on neurons in various types of preparations, including cell culture models, dissociated neurons, neurons in brain slices, and in intact anesthetized or awake animals. In summary, this technique has immensely contributed to the understanding of passive and active biophysical properties of excitable cells. A major advantage of this technique is that it provides information on how specific manipulations (e.g., pharmacological, experimenter-induced plasticity) may alter specific neuronal functions or channels in real-time. Additionally, significant opening of the plasma membrane allows the internal pipette solution to freely diffuse into the cytoplasm, providing means for introducing drugs, e.g., agonists or antagonists of specific intracellular proteins, and manipulating these targets without altering their functions in neighboring cells. This article will focus on whole-cell recording performed on neurons in brain slices,&#160;a preparation that has the advantage of recording neurons in relatively well preserved brain circuits, i.e., in a physiologically relevant context. In particular,&#160;when combined with appropriate pharmacology, this technique is a powerful tool allowing identification of specific neuroadaptations that occurred following any type of experiences, such as learning, exposure to drugs of abuse, and stress. In summary, whole-cell patch-clamp recordings in brain slices provide means to measure in ex vivo preparation long-lasting changes in neuronal functions that have developed in intact awake animals.

This protocol describes basic procedural steps for performing whole-cell patch-clamp recordings. This technique allows the study of&#160;the electrical behavior of neurons, and when performed in brain slices, allows the assessment of various neuronal functions from neurons that are still integrated in relatively well preserved brain circuits.

Whole-cell patch-clamp recording is an electrophysiological technique that allows the study of the&#160;electrical properties of a substantial part of the ...

The Preparation of Oblique Spinal Cord Slices for Ventral Root Stimulation

Electrophysiological recordings from spinal cord slices have proven to be a valuable technique to investigate a wide range of questions, from cellular to network properties. We show how to prepare viable oblique slices of the spinal cord of young mice (P2 - P11). In this preparation, the motoneurons retain&#160;their axons coming out from the ventral roots of the&#160;spinal cord. Stimulation of these axons elicits back-propagating action potentials invading the motoneuron&#160;somas and exciting the motoneuron&#160;collaterals within the spinal cord. Recording of antidromic action potentials is an immediate, definitive and elegant way to characterize motoneuron identity, which surpasses&#160;other identification methods. Furthermore, stimulating the motoneuron collaterals is a simple and reliable way to excite the collateral targets of the motoneurons within the spinal cord, such as other motoneurons or Renshaw cells. In this protocol, we present antidromic recordings from the motoneuron somas as well as Renshaw cell excitation, resulting from ventral root stimulation.

We show how to prepare oblique slices of the spinal cord in young mice. This preparation allows for the stimulation of the ventral roots.

Electrophysiological recordings from spinal cord slices have proven to be a valuable technique to investigate a wide range of questions, from cellular to ...

Whole-cell Patch-clamp Recordings for Electrophysiological Determination of Ion Selectivity in Channelrhodopsins

Over the past decade, channelrhodopsins became indispensable in neuroscientific research where they are used as tools to non-invasively manipulate electrical processes in target cells. In this context, ion selectivity of a channelrhodopsin is of particular importance. This article describes the investigation of chloride selectivity for a recently identified anion-conducting channelrhodopsin of Proteomonas sulcata via electrophysiological patch-clamp recordings on HEK293 cells. The experimental procedure for measuring light-gated photocurrents demands a fast switchable &#8211; ideally monochromatic &#8211; light source coupled into the microscope of an otherwise conventional patch-clamp setup. Preparative procedures prior to the experiment are outlined involving preparation of buffered solutions, considerations on liquid junction potentials, seeding and transfection of cells, and pulling of patch pipettes. The actual recording of current-voltage relations to determine the reversal potentials for different chloride concentrations takes place 24 h to 48 h after transfection. Finally, electrophysiological data are analyzed with respect to theoretical considerations of chloride conduction.

This article describes how the ion selectivity of channelrhodopsin is determined with electrophysiological whole-cell patch-clamp recordings using HEK293 cells. Here, the experimental procedure for investigating chloride selectivity of an anion-selective channelrhodopsin is demonstrated. However, the procedure is transferable to other channelrhodopsins of distinct selectivity.

Over the past decade, channelrhodopsins became indispensable in neuroscientific research where they are used as tools to non-invasively manipulate ...

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

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

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

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

Auditory Brainstem Response and Outer Hair Cell Whole-cell Patch Clamp Recording in Postnatal Rats

The outer hair cell is one of the two types of sensory hair cells in the mammalian cochlea. They alter their cell length with the receptor potential to amplify the weak vibration of low-level sound signal. The morphology and electrophysiological property of outer hair cells (OHCs) develop in early postnatal ages. The maturation of outer hair cell may contribute to the development of the auditory system. However, the process of OHCs development is not well studied. This is partly because of the difficulty to measure their function by an electrophysiological approach. With the purpose of developing a simple method to address the above issue, here we describe a step-by-step protocol to study the function of OHCs in acutely dissociated cochlea from postnatal rats. With this method, we can evaluate the cochlear response to pure tone stimuli and examine the expression level and function of the motor protein prestin in OHCs. This method can also be used to investigate the inner hair cells (IHCs).

This protocol describes methods to record the auditory brainstem response from postnatal rat pups. To examine the functional development of outer hair cells, the experimental procedure of whole-cell patch clamp recording in isolated outer hair cells is described step-by-step.

The outer hair cell is one of the two types of sensory hair cells in the mammalian cochlea. They alter their cell length with the receptor potential to ...

Preparations and Protocols for Whole Cell Patch Clamp Recording of Xenopus laevis Tectal Neurons

The Xenopus tadpole retinotectal circuit, comprised of the retinal ganglion cells (RGCs) in the eye which form synapses directly onto neurons in the optic tectum, is a popular model to study how neural circuits self-assemble. The ability to carry out whole cell patch clamp recordings from tectal neurons and to record RGC-evoked responses, either in vivo or using a whole brain preparation, has generated a large body of high-resolution data about the mechanisms underlying normal, and abnormal, circuit formation and function. Here we describe how to perform the in vivo preparation, the original whole brain preparation, and a more recently developed horizontal brain slice preparation for obtaining whole cell patch clamp recordings from tectal neurons. Each preparation has unique experimental advantages. The in vivo preparation enables the recording of the direct response of tectal neurons to visual stimuli projected onto the eye. The whole brain preparation allows for the RGC axons to be activated in a highly controlled manner, and the horizontal brain slice preparation allows recording from across all layers of the tectum.

Preparations and Protocols for Whole Cell Patch Clamp Recording of Xenopus laevis Tectal Neurons

In this paper, we discuss three brain preparations used for whole cell patch clamp recording to study the retinotectal circuit of Xenopus laevis tadpoles. Each preparation, with its own specific advantages, contributes to the experimental tractability of the Xenopus tadpole as a model to study neural circuit function.

The Xenopus tadpole retinotectal circuit, comprised of the retinal ganglion cells (RGCs) in the eye which form synapses directly onto neurons in the optic ...

Evaluation of Synaptic Multiplicity Using Whole-cell Patch-clamp Electrophysiology

In the central nervous system, a pair of neurons often form&#160;multiple synaptic contacts and/or functional neurotransmitter release sites (synaptic multiplicity). Synaptic multiplicity is plastic and changes throughout development and in different physiological conditions, being an important determinant for the efficacy of synaptic transmission. Here, we outline experiments for estimating the degree of multiplicity of synapses terminating onto a given postsynaptic neuron using whole-cell patch clamp electrophysiology in acute brain slices. Specifically, voltage-clamp recording is used to compare the difference between the amplitude of spontaneous excitatory postsynaptic currents (sEPSCs) and miniature excitatory postsynaptic currents (mEPSCs). The theory behind this method is that afferent inputs that exhibit multiplicity will show large, action potential-dependent sEPSCs due to the synchronous release that occurs at each synaptic contact. In contrast, action potential-independent release (which is asynchronous) will generate smaller amplitude mEPSCs. This article outlines a set of experiments and analyses to characterize the existence of synaptic multiplicity and discusses the requirements and limitations of the technique. This technique can be applied to investigate how different behavioral, pharmacological or environmental interventions in vivo affect the organization of synaptic contacts in different brain areas.

Here, we present a protocol for evaluating the functional synaptic multiplicity using whole-cell patch clamp electrophysiology in acute brain slices.

In the central nervous system, a pair of neurons often form&#160;multiple synaptic contacts and/or functional neurotransmitter release sites (synaptic ...

Preparation of Acute Slices from Dorsal Hippocampus for Whole-Cell Recording and Neuronal Reconstruction in the Dentate Gyrus of Adult Mice

Although the general architecture of the hippocampus is similar along its longitudinal axis, recent studies have revealed prominent differences in molecular, anatomical and functional criteria suggesting a division into different sub-circuits along its rostro-caudal extent. Owing to differential connectivity and function the most fundamental distinction is made between the dorsal and the ventral hippocampus, which are preferentially involved in spatial and emotional processing, respectively. Accordingly, in vivo work regarding spatial memory formation has focused on the dorsal hippocampus.
In contrast, electro-physiological in vitro recordings have been preferentially performed on intermediate-ventral hippocampus, largely motivated by factors like slice viability and circuit integrity. To allow for direct correlation of in vivo data on spatial processing with in vitro data we have adapted previous sectioning methods to obtain highly viable transverse brain slices from the dorsal-intermediate hippocampus for long-term recordings of principal cells and interneurons in the dentate gyrus. As spatial behavior is routinely analyzed in adult mice, we have combined this transversal slicing procedure with the use of protective solutions to enhance viability of brain tissue from mature animals. We use this approach for mice of about 3 months of age. The method offers a good alternative to the coronal preparation which is frequently used for in vitro studies on dorsal hippocampus. We compare these two preparations in terms of quality of recordings and preservation of morphological features of recorded neurons.

We present a protocol to prepare acute-slices from the dorsal-intermediate hippocampus of mice. We compare this transversal preparation with coronal slicing in terms of quality of recordings and preservation of morphological features of recorded neurons.

Although the general architecture of the hippocampus is similar along its longitudinal axis, recent studies have revealed prominent differences in ...

Hypothalamic Kisspeptin Neurons as a Target for Whole-Cell Patch-Clamp Recordings

Kisspeptins are essential for the maturation of the hypothalamic-pituitary-gonadal (HPG) axis and fertility. Hypothalamic kisspeptin neurons located in the anteroventral periventricular nucleus and rostral periventricular nucleus, as well as the arcuate nucleus of the hypothalamus, project to gonadotrophin-releasing hormone (GnRH) neurons, among other cells. Previous studies have demonstrated that kisspeptin signaling occurs through the Kiss1 receptor (Kiss1r), ultimately exciting GnRH neuron activity. In humans and experimental animal models, kisspeptins are sufficient for inducing GnRH secretion and, consequently, luteinizing hormone (LH) and follicle stimulant hormone (FSH) release. Since kisspeptins play an essential role in reproductive functions, researchers are working to assess how the intrinsic activity of hypothalamic kisspeptin neurons contributes to reproduction-related actions and identify the primary neurotransmitters/neuromodulators capable of changing these properties. The whole-cell patch-clamp technique has become a valuable tool for investigating kisspeptin neuron activity in rodent cells. This experimental technique allows researchers to record and measure spontaneous excitatory and inhibitory ionic currents, resting membrane potential, action potential firing, and other electrophysiological properties of cell membranes. In the present study, crucial aspects of the whole-cell patch-clamp technique, known as electrophysiological measurements that define hypothalamic kisspeptin neurons, and a discussion of relevant issues about the technique, are reviewed.

Here, we present a protocol to perform a whole-cell patch-clamp on brain slices containing kisspeptin neurons, the primary modulator of gonadotrophin-releasing hormone (GnRH) cells. By adding knowledge about kisspeptin neuron activity, this electrophysiological tool has served as the basis for significant advancements in the neuroendocrinology field over the last 20 years.

Kisspeptins are essential for the maturation of the hypothalamic-pituitary-gonadal (HPG) axis and fertility. Hypothalamic kisspeptin neurons located in ...