This work was supported by NIH Grant EY17606 (APS).

1. Preparing Electrodes
<ol>
<li>	Prepare the recording and reference electrodes by dipping them both in 1M NaCl and driving 15V between them using a 1 Hz sine wave for ~ 20 s.</li>
<li>	Make the recording electrodes using a micropipette puller (Sutter Instruments P-97). For patch-pipettes use a borosilicate glass with an outer diameter of 1.2 mm and an inner diameter of 0.69 mm (Sutter Instruments, Cat#B120-69-10). Measure the series resistance through the tip of the electrode. Based on the size of the target cells choose an pipette tip diameter; for cell bodies ~ 20 &mu;m in diameter use ~ 5 M&Omega; for cell bodies ~ 5 &mu;m in diameter use ~ 12 M&Omega;.</li>
<li>	Prepare ground/reference electrodes. Using a syringe fill a small section polyethylene tubing (Intramedic, PE205) with 1 mM NaCl that includes 3.5% Agar (Sigma; Cat# A7002) in 1M NaCl. Place this agar bridge over the Ag/AgCl reference electrode.</li>
</ol>
2. Preparing Solutions
<ol>
<li>	External bath solution, Ames' media containing Bicarbonate (1 L): 1 bottle of Ames' Medium (Sigma; Cat# A1420), 1.9 g of NaHCO3, 7 mL of Penicillin-Streptomycin (Sigma; Cat# P0781) to prevent bacterial growth. Adjust osmolarity to ~ 280 mOsm.</li>
<li>	Slicing solution, Ames' media containing the pH buffer HEPES (1 L): 1 bottle of Ames' Medium, 0.887 g of NaCl, 2.38 g of HEPES, 7 mL of Penicillin-Streptomycin. Adjust pH to ~ 7.4 using 1M NaOH and/or 1M HCl. Adjust osmolarity to ~ 280 mOsm.</li>
<li>	Potassium-Aspartate (K-Asp) pipette internal solution (in mM): 125 K-Aspartate, 10 KCl, 10 HEPES, 5 NMG-HEDTA, 0.5 CaCl2, 1 ATP-Mg, 0.2 GTP-Mg; pH is adjusted to ~ 7.3 with NMG-OH, and osmolarity is adjusted to ~ 280 mOsm.</li>
<li>	Agar backstop for stabilizing low gelling temperature agarose containing the retina (5% by weight), 7.5 g of Agar (Sigma; Cat# A7002) melted in 150 mL of dH2O.</li>
</ol>

3. Day of Experiment
<ol>
<li>	Thaw ~ 1.5 mL of K-Asp Internal Solution and the fluorophore of your choice from freezer. Dilute the fluorophore to the appropriate concentration, which should be determined empirically.</li>
<li>	Pour Ames' media containing NaHCO3 (~ 200 mL) into the light-tight storage container and then place into the water bath (30-32&deg;C) and equilibrate with 5% CO2/95% O2 gas</li>
<li>	Fill bottle with ~ 110 mL of Ames' media containing HEPES, place on ice and equilibrate with 100% O2.</li>
<li>	Place the remaining Ames' media containing NaHCO3 in a heated reservoir on top of the Faraday cage, and equilibrate with 5% CO2/95% O2 gas. Parafilm may be used to trap the gas in the space above the solution.</li>
<li>	Prepare the low gelling temperature agarose (3%) by adding 0.75 g (Sigma; Cat#A0701) to 25 mL of Ames' media with HEPES and heat the solution at ~ 115&deg;C to melt the agarose. Stir until the solution clear without bubbles, and store in a water bath (~ 42&deg;C).</li>
<li>	Fill a recording pipette with the K-Asp internal solution and check the tip resistance. </li>
</ol>
4. Begin Experiment
<ol>
<li>	Euthanize the mouse and quickly remove the eyes using curved scissors. Infrared goggles should be used for all procedures to prevent bleaching of the visual pigment. </li>
<li>	Place the eyes on a piece of filter paper to prevent them from rolling, and using a thin double sided blade, make a slit in the cornea while holding the eye with the forceps.</li>
<li>	As soon the eyeball is punctured, transfer they eye into a dish filled with Ames' media.</li>
<li>	Using the slit in the cornea as an entry point, small scissors are used to cut away the remaining portions of the cornea, after which the lens and vitreous can be removed. Be careful that the retina remains attached to the eyecup, and store the eyecup in darkness at 32&deg; C in Ames' media equilibrated with 5% CO2/95% O2.</li>
</ol>
5. Slicing
<ol>
<li>	Hemisect one of the eyecups and dissociate the retina from the retinal pigment epithelium. Remove the edges of the retina to allow the tissue to lie flat.</li>
<li>	Use a small glass Pasteur pipette with a latex bulb to fill a 35 mm Petri dish with melted agar, and drag the forceps across through the agar to test its consistency.</li>
<li>	When you can begin to see the agar solidify:
<ol class="lalpha">
<li>	Transfer the retina to the top of the agar.</li>
<li>	Use a twisted piece of Kimwipe to absorb the excess solution around the retina. </li>
<li>	Place 2-3 drops of Agar directly onto the retina and quickly place a plastic cylinder over the retina to form a wall around it. Then drip additional melted agar down the sides of the plastic cylinder while centering the retina within the agar. </li>
<li>	Transfer the Petri dish to an ice water bath to cool. </li></ol></li>
<li>	After ~ 45 seconds remove the tissue from the ice water bath and use a plunger to extrude the agar block out of the plastic cylinder, pushing from the side farthest from the retina. </li>
<li>	Use the one-sided razor blade to cut out a small block of agar containing the retina and superglue the block into place against the agar backstop on the specimen disc.</li>
<li>	Transfer the specimen disc to the vibrating microtome tray and pour ice cold Ames HEPES into the tray allowing the block with retina to be fully submersed.</li>
<li>	Retinal slices with a thickness of ~ 200 &mu;m can be cut at the maximum blade vibrating rate and a forward blade speed set such that it takes 4 to 5 seconds to cut through the retina on each slice.</li>
<li>	Use a No. 11 scalpel blade to remove each usable slice one at a time</li>
<li>	Good slices containing retina are placed into recording chambers and are weighted down with slice anchors with nylon threads crossing them. The nylon threads hold down the agar surrounding the retina, leaving the retina unobstructed for recordings.</li>
<li>	Transfer the recording chamber to the stage of the upright microscope, close the curtain and turn on the infrared light source to view the slice on an infrared-sensitive camera. </li>
</ol>
6. Recording
<ol>
<li>	Once a good retinal slice (with intact photoreceptors and the appropriate cutting angle) is identified begin perfusing the retina at a rate greater than 5 mL/min with heated Ames' media that is heated to 35 37&deg;C and equilibrated with 5% CO2/95% O2.</li>
<li>	Some surface damage may be apparent due to the slicing process. This usually thin layer of cells can be removed using a pipette with a broken tip, and gently sucking away the dead cell bodies. This will typically reveal live cells underneath. Identify a healthy cell body whose position is located in the strata of interest.</li>
<li>	Fill a micropipette with the KAsp internal solution and apply positive (outward) pressure through the tip of the pipette, and lower the tip of the pipette into the recording chamber and down to the level of the cell using a micromanipulator.</li>
<li>	Move the pipette tip such that it dimples the cell membrane, and apply gentle negative (inward) pressure to make a high resistance seal. Whole-cell mode can be achieved by applying negative pressure to the electrode to break into the cell.</li>
<li>	Stimulating the retinal tissue using LEDs can then evoke responses to light.</li>
<li>	Photograph the cell from which the recording was made by evoking fluorescence from the fluorophore in the pipette internal solution.</li>
</ol>

7. Representative Results
<img src="/files/ftp_upload/2107/2107fig1.jpg" alt="Figure 1" /> 
Figure 1. Here, light-evoked potentials of a dark-adapted retinal neuron to flashes of light of increasing strength are shown.
<img src="/files/ftp_upload/2107/2107fig2.jpg" alt="Figure 2" /> 
Figure 2. Fluorescence picture from a retinal slice where cells have been filled with the fluorophore, Lucifer Yellow. Evoked fluorescence shows the morphology of cells from which patch recordings were made.

<ol>
	<li>Weblin, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transmission+along+and+between+rods+in+the+tiger+salamander+retina.">Transmission along and between rods in the tiger salamander retina.</a> J Physiol. 280, 449-470 (1978).</li><li>Wu, 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=Synaptic+connections+among+retina+neurons+in+living+slices.">Synaptic connections among retina neurons in living slices.</a> J Neurosci Methods. 20, 139-149 (1987).</li><li>Rieke, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Temporal+contrast+adaptation+in+salamander+bipolar+cell.">Temporal contrast adaptation in salamander bipolar cell.</a> J Neurosci. 21, 9445-9454 (2001).</li><li>Armstrong-Gold, C., &amp;amp, R. i. e. k. e., F, . <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bandpass+filtering+at+the+rod+to+second-order+cell+synapse+in+salamander+(Ambystoma+tigrinum)+retina.">Bandpass filtering at the rod to second-order cell synapse in salamander (Ambystoma tigrinum) retina.</a> J Neurosci. 23, 3796-3806 (2003).</li><li>Masland, R. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+fundamental+plan+of+the+retina.">The fundamental plan of the retina.</a> Nat Neurosci. 4, 877-886 (2001).</li><li>Wassle, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Parallel+processing+in+the+mammalian+retina.">Parallel processing in the mammalian retina.</a> Nat Rev Neurosci. 5, 747-757 (2004).</li></ol>

No conflicts of interest declared.

Slice recording from vertebrate retinas have been made for decades1,2, and have been quite successful in providing a deeper understanding of how the retinal circuitry encodes incident light. The advantages of cutting with a vibrating microtome rather than directly with a razor blade is that the retinal slices incur less damage at the surface. With a suction pipette it is easy to remove this damage and target healthy cells just below the surface that retain their connectivity in the retinal circuit, where mos...

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		<div>
		<table border="1">
		<thead>
		<tr>
		<th>Material Name</th>
		<th>Type</th>
		<th>Company</th>
		<th>Catalogue Number</th>
		<th>Comment</th>
		</tr>
		</thead>
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<tr>
<td>Micropipette Puller</td>
<td>&nbsp;</td>
<td>Sutter Instruments</td>
<td>P-97</td>
<td>&nbsp;</td>
<tr>
<td>Borosilicate glass</td>
<td>&nbsp;</td>
<td>Sutter Instruments</td>
<td>B120-69-10</td>
<td>&nbsp;</td>
<tr>
<td>Polyethylene tubing</td>
<td>&nbsp;</td>
<td>Intramedic</td>
<td>PE205</td>
<td>&nbsp;</td>
<tr>
<td>Agar</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>A7002</td>
<td>&nbsp;</td>
<tr>
<td>Low gelling temp agarose</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>A0701</td>
<td>&nbsp;</td>
<tr>
<td>Ames' Medium</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>A1420</td>
<td>&nbsp;</td>
<tr>
<td>Penicillin-Streptomycin</td>
<td>&nbsp;</td>
<td>Sigma</td>
<td>P0781</td>
<td>&nbsp;</td>		</tbody>
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		</div>

patch clamp recordings from mouse retinal neurons in a dark-adapted slice preparation

Our visual experience is initiated when the visual pigment in our retinal photoreceptors absorbs photons of light energy and initiates a cascade of intracellular events that lead to closure of cyclic-nucleotide-gated channels in the cell membrane. The resulting change in membrane potential leads in turn to reductions in the amount of neurotransmitter release from both rod and cone synaptic terminals. To measure how the light-evoked change in photoreceptor membrane potential leads to downstream activity in the retina, scientists have made electrophysiological recordings from retinal slice preparations for decades1,2. In the past these slices have been cut manually with a razor blade on retinal tissue that is attached to filter paper; in recent years another method of slicing has been developed whereby retinal tissue is embedded in low gelling temperature agar and sliced in cool solution with a vibrating microtome3,4. This preparation produces retinal slices with less surface damage and very robust light-evoked responses. Here we document how this procedure can be done under infrared light to avoid bleaching the visual pigment.

Watch this Scientific Journal Video about Patch Clamp Recordings from Mouse Retinal Neurons in a Dark-adapted Slice Preparation at JoVE.com

Patch Clamp Recordings from Mouse Retinal Neurons in a Dark-adapted Slice Preparation

Here we describe a procedure for generating dark-adapted slices of the mouse retina for electrophysiological recordings.

Our visual experience is initiated when the visual pigment in our retinal photoreceptors absorbs photons of light energy and initiates a cascade of ...

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Neuroscience

14.3K Views.  University of Southern California. Here we describe a procedure for generating dark-adapted slices of the mouse retina for electrophysiological recordings.

Video: Patch Clamp Recordings from Mouse Retinal Neurons in a Dark-adapted Slice Preparation

Paired Patch Clamp Recordings from Motor-neuron and Target Skeletal Muscle in Zebrafish

Larval zebrafish represent the first vertebrate model system to allow simultaneous patch clamp recording from a spinal motor-neuron and target muscle. This is a direct consequence of the accessibility to both cell types and ability to visually distinguish the single segmental CaP motor-neuron on the basis of morphology and location. This video demonstrates the microscopic methods used to identify a CaP motor-neuron and target muscle cells as well as the methodologies for recording from each cell type. Identification of the CaP motor-neuron type is confirmed by either dye filling or by the biophysical features such as action potential waveform and cell input resistance. Motor-neuron recordings routinely last for one hour permitting long-term recordings from multiple different target muscle cells. Control over the motor-neuron firing pattern enables measurements of the frequency-dependence of synaptic transmission at the neuromuscular junction. Owing to a large quantal size and the low noise provided by whole cell voltage clamp, all of the unitary events can be resolved in muscle. This feature permits study of basic synaptic properties such as release properties, vesicle recycling, as well as synaptic depression and facilitation. The advantages offered by this in vivo preparation eclipse previous neuromuscular model systems studied wherein the motor-neurons are usually stimulated by extracellular electrodes and the muscles are too large for whole cell patch clamp. The zebrafish preparation is amenable to combining electrophysiological analysis with a wide range of approaches including transgenic lines, morpholino knockdown, pharmacological intervention and in vivo imaging. These approaches, coupled with the growing number of neuromuscular disease models provided by mutant lines of zebrafish, open the door for new understanding of human neuromuscular disorders.

Larval zebrafish represent the first vertebrate model system to allow simultaneous patch clamp recording from a spinal motor-neuron and target skeletal muscle. This video demonstrates the microscopic methods used to identify a segmental CaP motor-neuron and target muscle cells as well as the methodologies for recording from each cell type.

Larval zebrafish represent the first vertebrate model system to allow simultaneous patch clamp recording from a spinal motor-neuron and target muscle.  ...

Patch Clamp Recordings in Inner Ear Hair Cells Isolated from Zebrafish

Patch clamp analyses of the voltage-gated channels in sensory hair cells isolated from a variety of species have been described previously1-4 but this video represents the first application of those techniques to hair cells from zebrafish. Here we demonstrate a method to isolate healthy, intact hair cells from all of the inner ear end-organs: saccule, lagena, utricle and semicircular canals. Further, we demonstrate the diversity in hair cell size and morphology and give an example of the kinds of patch clamp recordings that can be obtained. The advantage of the use of this zebrafish model system over others stems from the availability of zebrafish mutants that affect both hearing and balance. In combination with the use of transgenic lines and other techniques that utilize genetic analysis and manipulation, the cell isolation and electrophysiological methods introduced here should facilitate greater insight into the roles hair cells play in mediating these sensory modalities.

The purpose of this video is to demonstrate procedures for obtaining healthy, intact hair cells from the inner ear organs of adult zebrafish and then using them for patch clamp studies aimed at characterizing the biophysical properties of their voltage-gated channels.

Patch  clamp analyses of the voltage-gated channels in sensory hair cells isolated  from a variety of species have been described previously1-4 but this  ...

F1FO ATPase Vesicle Preparation and Technique for Performing Patch Clamp Recordings of Submitochondrial Vesicle Membranes

Mitochondria are involved in many important cellular functions including metabolism, survival1, development and, calcium signaling2. Two of the most important mitochondrial functions are related to the efficient production of ATP, the energy currency of the cell, by oxidative phosphorylation, and the mediation of signals for programmed cell death3.
The enzyme primarily responsible for the production of ATP is the F1FO-ATP synthase, also called ATP synthase4-5. In recent years, the role of mitochondria in apoptotic and necrotic cell death has received considerable attention. In apoptotic cell death, BCL-2 family proteins such as Bax enter the mitochondrial outer membrane, oligomerize and permeabilize the outer membrane, releasing pro-apoptotic factors into the cytosol6. In classic necrotic cell death, such as that produced by ischemia or excitotoxicity in neurons, a large, poorly regulated increase in matrix calcium contributes to the opening of an inner membrane pore, the mitochondrial permeability transition pore or mPTP. This depolarizes the inner membrane and causes osmotic shifts, contributing to outer membrane rupture, release of pro-apoptotic factors, and metabolic dysfunction. Many proteins including Bcl-xL7 interact with F1FO ATP synthase, modulating its function. Bcl-xL interacts directly with the beta subunit of F1FO ATP synthase, and this interaction decreases a leak conductance within the F1FOATPasecomplex, increasing the net transport of H+ by F1FO during F1FO ATPase activity8 and thereby increasing mitochondrial efficiency. To study the activity and modulation of the ATP synthase, we isolated from rodent brain submitochondrial vesicles (SMVs) containing F1FO ATPase. The SMVs retain the structural and functional integrity of the F1FO ATPase as shown in Alavian et al. Here, we describe a method that we have used successfully for the isolation of SMVs from rat brain and we delineate the patch clamp technique to analyze channel activity (ion leak conductance) of the SMVs.

F1FO ATPase Vesicle Preparation and Technique for Performing Patch Clamp Recordings of Submitochondrial Vesicle Membranes

A method to isolate submitochondrial vesicles enriched in F1FO ATP synthase complexes from rat brain is described. These vesicles allow the study of the activity of F1FO ATPase complex and its modulation using the technique of patch clamp recording.

Mitochondria are involved in many important cellular  functions including metabolism, survival1, development and, calcium signaling2. Two of the most ...

Simultaneous Whole-cell Recordings from Photoreceptors and Second-order Neurons in an Amphibian Retinal Slice Preparation

One of the central tasks in retinal neuroscience is to understand the circuitry of retinal neurons and how those connections are responsible for shaping the signals transmitted to the brain. Photons are detected in the retina by rod and cone photoreceptors, which convert that energy into an electrical signal, transmitting it to other retinal neurons, where it is processed and communicated to central targets in the brain via the optic nerve. Important early insights into retinal circuitry and visual processing came from the histological studies of Cajal1,2 and, later, from electrophysiological recordings of the spiking activity of retinal ganglion cells - the output cells of the retina3,4.
A detailed understanding of visual processing in the retina requires an understanding of the signaling at each step in the pathway from photoreceptor to retinal ganglion cell. However, many retinal cell types are buried deep in the tissue and therefore relatively inaccessible for electrophysiological recording. This limitation can be overcome by working with vertical slices, in which cells residing within each of the retinal layers are clearly visible and accessible for electrophysiological recording.
Here, we describe a method for making vertical sections of retinas from larval tiger salamanders (Ambystoma tigrinum). While this preparation was originally developed for recordings with sharp microelectrodes5,6, we describe a method for dual whole-cell voltage clamp recordings from photoreceptors and second-order horizontal and bipolar cells in which we manipulate the photoreceptor's membrane potential while simultaneously recording post-synaptic responses in horizontal or bipolar cells. The photoreceptors of the tiger salamander are considerably larger than those of mammalian species, making this an ideal preparation in which to undertake this technically challenging experimental approach. These experiments are described with an eye toward probing the signaling properties of the synaptic ribbon - a specialized synaptic structure found in a only a handful of neurons, including rod and cone photoreceptors, that is well suited for maintaining a high rate of tonic neurotransmitter release7,8 - and how it contributes to the unique signaling properties of this first retinal synapse.

We describe the preparation of thin retinal slices from aquatic tiger salamanders (Ambystoma tigrinum) and explain how we use these slices to study synaptic processing in the retina by obtaining dual whole-cell voltage clamp recordings from photoreceptors and second-order horizontal and bipolar cells.

One of the central tasks in retinal neuroscience  is to understand the circuitry of retinal neurons and how those connections are  responsible for shaping ...

Isolation of Sensory Neurons of Aplysia californica for Patch Clamp Recordings of Glutamatergic Currents

The marine gastropod mollusk Aplysia californica has a venerable history as a model of nervous system function, with particular significance in studies of learning and memory. The typical preparations for such studies are ones in which the sensory and motoneurons are left intact in a minimally dissected animal, or a technically elaborate neuronal co-culture of individual sensory and motoneurons. Less common is the isolated neuronal preparation in which small clusters of nominally homogeneous neurons are dissociated into single cells in short term culture. Such isolated cells are useful for the biophysical characterization of ion currents using patch clamp techniques, and targeted modulation of these conductances. A protocol for preparing such cultures is described. The protocol takes advantage of the easily identifiable glutamatergic sensory neurons of the pleural and buccal ganglia, and describes their dissociation and minimal maintenance in culture for several days without serum.

Isolation of Sensory Neurons of Aplysia californica for Patch Clamp Recordings of Glutamatergic Currents

We describe the dissection of the nervous system of the marine sea hare Aplysia after anesthesia, the isolation of neurons for short term-tissue culture, and recordings of single cell ion currents via the patch clamp technique.

The marine gastropod mollusk Aplysia californica has a venerable  history as a model of nervous system function, with particular significance in  studies ...

Patch Clamp Recordings from Embryonic Zebrafish Mauthner Cells

Mauthner cells (M-cells) are large reticulospinal neurons located in the hindbrain of teleost fish. They are key neurons involved in a characteristic behavior known as the C-start or escape response that occurs when the organism perceives a threat. The M-cell has been extensively studied in adult goldfish where it has been shown to receive a wide range of excitatory, inhibitory and neuromodulatory signals1. We have been examining M-cell activity in embryonic zebrafish in order to study aspects of synaptic development in a vertebrate preparation. In the late 1990s Ali and colleagues developed a preparation for patch clamp recording from M-cells in zebrafish embryos, in which the CNS was largely intact2,3,4. The objective at that time was to record synaptic activity from hindbrain neurons, spinal cord neurons and trunk skeletal muscle while maintaining functional synaptic connections within an intact brain-spinal cord preparation. This preparation is still used in our laboratory today. To examine the mechanisms underlying developmental synaptic plasticity, we record excitatory (AMPA and NMDA-mediated)5,6 and inhibitory (GABA and glycine) synaptic currents from developing M-cells. Importantly, this unique preparation allows us to return to the same cell (M-cell) from preparation to preparation to carefully examine synaptic plasticity and neuro-development in an embryonic organism. The benefits provided by this preparation include 1) intact, functional synaptic connections onto the M-cell, 2) relatively inexpensive preparations, 3) a large supply of readily available embryos 4) the ability to return to the same cell type (i.e. M-cell) in every preparation, so that synaptic development at the level of an individual cell can be examined from fish to fish, and 5) imaging of whole preparations due to the transparent nature of the embryos.

We have developed an intact brain-spinal cord preparation to record and monitor electrical activity via patch clamp recording from the Mauthner neurons and other reticulospinal cells in zebrafish embryos. Thus, we are able to record excitatory and inhibitory synaptic currents, voltage-gated channel activity and action potentials from key neurons in a developing embryo.

Mauthner cells (M-cells) are large  reticulospinal neurons located in the hindbrain of teleost fish. They are key  neurons involved in a characteristic ...

Whole-cell Patch-clamp Recordings from Morphologically- and Neurochemically-identified Hippocampal Interneurons

GABAergic inhibitory interneurons play a central role within neuronal circuits of the brain. Interneurons comprise a small subset of the neuronal population (10-20%), but show a high level of physiological, morphological, and neurochemical heterogeneity, reflecting their diverse functions. Therefore, investigation of interneurons provides important insights into the organization principles and function of neuronal circuits. This, however, requires an integrated physiological and neuroanatomical approach for the selection and identification of individual interneuron types. Whole-cell patch-clamp recording from acute brain slices of transgenic animals, expressing fluorescent proteins under the promoters of interneuron-specific markers, provides an efficient method to target and electrophysiologically characterize intrinsic and synaptic properties of specific interneuron types. Combined with intracellular dye labeling, this approach can be extended with post-hoc morphological and immunocytochemical analysis, enabling systematic identification of recorded neurons. These methods can be tailored to suit a broad range of scientific questions regarding functional properties of diverse types of cortical neurons.

Cortical networks are controlled by a small, but diverse set of inhibitory interneurons. Functional investigation of interneurons therefore requires targeted recording and rigorous identification. Described here is a combined approach involving whole-cell recordings from single or synaptically-coupled pairs of neurons with intracellular labeling, post-hoc morphological and immunocytochemical analysis.

GABAergic inhibitory interneurons play a central role within neuronal circuits of the brain. Interneurons comprise a small subset of the neuronal ...

Recording Light-evoked Postsynaptic Responses in Neurons in Dark-adapted, Mouse Retinal Slice Preparations Using Patch Clamp Techniques

The retina is the gateway to the visual system. To understand visual signal processing mechanisms, we investigate retinal neural network functions. Retinal neurons in the network comprise of numerous subtypes. More than 10 subtypes of bipolar cells, ganglion cells, and amacrine cells have been identified by morphological studies. Multiple subtypes of retinal neurons are thought to encode distinct features of visual signaling, such as motion and color, and form multiple neural pathways. However, the functional roles of each neuron in visual signal processing are not fully understood. The patch clamp method is useful to address this fundamental question. Here, a protocol to record light-evoked synaptic responses in mouse retinal neurons using patch clamp recordings in dark-adapted conditions is provided. The mouse eyes are dark-adapted O/N, and retinal slice preparations are dissected in a dark room using infrared illumination and viewers. Infrared light does not activate mouse photoreceptors and thus preserves their light responsiveness. Patch clamp is used to record light-evoked responses in retinal neurons. A fluorescent dye is injected during recordings to characterize neuronal morphological subtypes. This procedure enables us to determine the physiological functions of each neuron in the mouse retina.

We will demonstrate how to prepare retinal slices from the mouse eye and record light responses in retinal neurons. The entire procedure is conducted in dark-adapted conditions.

The retina is the gateway to the visual system. To understand visual signal processing mechanisms, we investigate retinal neural network functions. ...

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 ...

Subcellular Patch-clamp Recordings from the Somatodendritic Domain of Nigral Dopamine Neurons

Dendrites of dopaminergic neurons receive and convey synaptic input, support action potential back-propagation and neurotransmitter release. Understanding these fundamental functions will shed light on the information transfer in these neurons. Dendritic patch-clamp recordings provide the possibility to directly examine the electrical properties of dendrites and underlying voltage-gated ion channels. However, these fine structures are not easily accessible to patch pipettes because of their small diameter. This report describes a step-by-step procedure to collect stable and reliable recordings from the dendrites of dopaminergic neurons in acute slices. Electrophysiological measurements are combined with post hoc recovery of cell morphology. Successful experiments rely on improved preparation of slices, solutions and pipettes, adequate adjustment of the optics and stability of the pipette in contact with the recorded structure. Standard principles of somatic patch-clamp recording are applied to dendrites but with a gentler approach of the pipette. These versatile techniques can be implemented to address various questions concerning the excitable properties of dendrites.

Subcellular patch-clamp recordings offer the possibility to investigate the functional properties of dendrites. However these fine structures are not easily accessible due to their small diameter. The protocol described here aims to facilitate the collection of stable and reliable recordings from the dendrites of dopamine neurons in slices in vitro.

Dendrites of dopaminergic neurons receive and convey synaptic input, support action potential back-propagation and neurotransmitter release. Understanding ...