We acknowledge Drs. Jing Bing Xue and Ruth Anne Eatock for their early contributions to these methods. This work was supported by NIH NIDCD R03 DC012652 and NIH NIDCD DC012653S, and R01 DC0155512 to RK and T32 DC009975 to DB, NN, and KR.

All animal use described here has been approved by the Institutional Animal Care and Use Committee at the University of Southern California. Animals in this protocol are P3- to P25-aged Long Evans rats of both sexes obtained from Charles River Laboratories, but these methods can be applied to other rodent strains. A laboratory coat and gloves must be worn during all procedures, as well as splash-protective goggles when making solutions.
1. Preparations
<p class="jove_content...

<ol>
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The authors declare that there are no conflicts of interest.

The methods presented here are specific to recordings from isolated neurons; previous studies have focused on recordings from axon terminals in a semi-intact preparation. When compared to existing terminal recording techniques, isolated recordings offer superior space-clamp and iso-potential behavior. In addition, this protocol provides access to a broader sample of neurons, since only calyx-bearing subpopulations are accessible in semi-intact recordings of the vestibular epithelia. Finally, isolated recordings allow for...

The bipolar neurons of the vestibulocochlear nerve connect the sensory hair cells of the inner ear to the brainstem. They are principal carriers of information about sound and head movements; damage to these important cells leads to deafness and balance disorders. The vestibular and auditory portions of the nerve are each comprised of distinct cell types that are&#160;morphologically and functionally diverse1,2. In the vestibular system, two afferent subpopulations fire spontaneously at intervals that are either regular or irregular2. Afferent spike timing is thought to reflect an underlying diversity in ion channel composition3,4. In the auditory system, there are two main subpopulations of spiral ganglion neurons (SGNs); whereas Type I SGNs contact individual inner hair cells5, Type II SGNs contact multiple outer hair cells5. In vitro recordings from semi-intact and organotypic cultures suggest differences in the membrane properties of Type I and Type II SGNs6,7.
Many ion channels and neurotransmitter receptors found at the terminals of these neurons are also found in their cell bodies. As such, cultures of the isolated vestibular and the spiral ganglion somata can be studied in vitro to understand how ion channels and neurotransmitter receptors contribute to the response of these neurons. The compact morphology of the isolated cell bodies allows for high-quality electrical recordings, suitable for detailed characterization of voltage-gated ion channels and neurotransmitter receptors. Easy access to a representative variety of neuron subtypes allows for high-throughput analysis of cell diversity.
This article presents a method for isolating and culturing dissociated ganglion cell bodies from the superior portion of the vestibular ganglion in rats at postnatal day (P)9 to P20. Suggestions are also provided for extending these methods to the spiral ganglion, in addition to the steps required for successfully extracting, dissociating, and plating the ganglion cells. These methods are an evolution of those devised in publications from various laboratories8,9,10. Also included in this paper is guidance for selecting healthy cells for patch-clamp recordings.
Finally, the protocol outlines the procedure for patch-clamp recording using the perforated-patch configuration11. Though the perforated-patch configuration is more time-consuming and more technically challenging than the more common ruptured-patch configuration, it is better for maintaining the cytoplasmic milieu that allows for long and stable recording sessions. The benefits of this recording configuration are illustrated here through the improved stability of hyperpolarization-activated cationic currents in perforated-patch relative to ruptured-patch recordings.
This protocol is organized into five sections. Sections 1-3 describe solutions and tools that can be prepared and stored ahead of time. Section 4 describes the steps for dissecting and plating the vestibular and SGNs. Section 5 describes the steps for recording from the neurons after a period in culture. In our hands, section 4 and section 5 are performed over a period of 2 consecutive days.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Amphotericin</td>
			<td>Sigma-Aldrich</td>
			<td>A4888-100MG</td>
			<td>For perforated patch recordings.</td>
		</tr>
		<tr>
			<td>ATP di-sodium</td>
			<td>Sigma-Aldrich</td>
			<td>A7699</td>
			<td>Additive to internal solution</td>
		</tr>
		<tr>
			<td>B27 Supplement (50x), serum free</td>
			<td>Thermo Fisher Scientific</td>
			<td>17504044</td>
			<td>additive to culture medium, for SGN</td>
		</tr>
		<tr>
			<td>Beakers (1000, 100, 10) milliliter</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>bench-top centrifuge</td>
			<td>USA Scientific</td>
			<td>2641-0016</td>
			<td></td>
		</tr>
		<tr>
			<td>Bunsen burner</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>CaCl2</td>
			<td>J.T. Baker</td>
			<td>1311-01</td>
			<td>Additive to internal solution</td>
		</tr>
		<tr>
			<td>Collagenase</td>
			<td>Sigma-Aldrich</td>
			<td>C5318</td>
			<td>one out of three enzyme to digest tissue</td>
		</tr>
		<tr>
			<td>Coverglass, rectangular, #1 thickness, 22x40&#160;</td>
			<td>Warner Instruments</td>
			<td>64-0707</td>
			<td></td>
		</tr>
		<tr>
			<td>DMSO</td>
			<td>Biotium</td>
			<td>90082</td>
			<td></td>
		</tr>
		<tr>
			<td>Dnase I,from bovine pancreas</td>
			<td>Sigma-Aldrich</td>
			<td>11284932001</td>
			<td>one out of three enzyme to digest tissue</td>
		</tr>
		<tr>
			<td>Dumont #3 Forceps (Blunt)</td>
			<td>Fine Science Tools</td>
			<td>11231-30</td>
			<td></td>
		</tr>
		<tr>
			<td>Dumont #5 Forceps (Fine)</td>
			<td>Fine Science Tools</td>
			<td>11251-10</td>
			<td></td>
		</tr>
		<tr>
			<td>Dumont #55 Forceps (Fine)</td>
			<td>Fine Science Tools</td>
			<td>11255-20</td>
			<td></td>
		</tr>
		<tr>
			<td>EGTA</td>
			<td>Sigma-Aldrich</td>
			<td>E0396</td>
			<td>Additive to internal solution</td>
		</tr>
		<tr>
			<td>Electrode Puller</td>
			<td>Narashige</td>
			<td>PC-10</td>
			<td></td>
		</tr>
		<tr>
			<td>Epi-illumination light source&#160;</td>
			<td>Zeiss&#160;</td>
			<td>CL 1500 ECO</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol</td>
			<td>Decon Labs</td>
			<td>2716</td>
			<td>for cleaning head and around dissection bench</td>
		</tr>
		<tr>
			<td>Filamented Borosilicate Capillaries for electrodes</td>
			<td>Sutter Instruments</td>
			<td>BF140-117-10</td>
			<td></td>
		</tr>
		<tr>
			<td>Fine-edged dissection blade</td>
			<td>Fine Science Tools</td>
			<td>10010-00</td>
			<td></td>
		</tr>
		<tr>
			<td>Glass Pasteur Pipettes</td>
			<td>VWR</td>
			<td>14673-010</td>
			<td>to pull trituration pipettes</td>
		</tr>
		<tr>
			<td>Heat-inactivated Fetal Bovine Serum</td>
			<td>Thermo Fisher Scientific</td>
			<td>16140063</td>
			<td>additive to culture medium</td>
		</tr>
		<tr>
			<td>HEPES</td>
			<td>Sigma-Aldrich</td>
			<td>H3375-100G</td>
			<td>for pH buffering all solutions in protocol</td>
		</tr>
		<tr>
			<td>Hot plate / magnetic stirrers&#160;</td>
			<td>VWR</td>
			<td>76549-914</td>
			<td></td>
		</tr>
		<tr>
			<td>Insulated bucket filled with ice</td>
			<td></td>
			<td></td>
			<td>to keep all samples and solutions cool</td>
		</tr>
		<tr>
			<td>K2SO4, Potassium Sulfate</td>
			<td>Sigma Aldrich</td>
			<td>P9458-250G</td>
			<td>Additive to internal solution</td>
		</tr>
		<tr>
			<td>KCl</td>
			<td>Sigma-Aldrich</td>
			<td>P93333</td>
			<td>Additive to internal solution</td>
		</tr>
		<tr>
			<td>KOH (1 M)</td>
			<td>Honeywell</td>
			<td>319376-500ML</td>
			<td>To bring internal solution to desired pH.</td>
		</tr>
		<tr>
			<td>Large Spring Scissors</td>
			<td>Fine Science Tools</td>
			<td>14133-13</td>
			<td></td>
		</tr>
		<tr>
			<td>Leibovitz medium&#160;</td>
			<td>Sigma Aldrich</td>
			<td>L4386</td>
			<td>dissection and bath solutions&#160;</td>
		</tr>
		<tr>
			<td>Low-profile-bath recording chamber for culture dishes</td>
			<td>Warner Instruments</td>
			<td>64-0236</td>
			<td></td>
		</tr>
		<tr>
			<td>luer-lok syringes, 30 ml</td>
			<td>BD</td>
			<td>302832</td>
			<td>for drawing L-15/HEPES/HEPES solution.</td>
		</tr>
		<tr>
			<td>MEM + Glutamax Supplement</td>
			<td>Fisher Scientific</td>
			<td>41-090-101</td>
			<td>base of the culture medium</td>
		</tr>
		<tr>
			<td>MgCl2-Hexahydrate</td>
			<td>Sigma-Aldrich</td>
			<td>M1028</td>
			<td>Additive to internal solution</td>
		</tr>
		<tr>
			<td>microFil needle for filling micropipettes - 34 gauge&#160;</td>
			<td>World Precision Instruments</td>
			<td>MF34G</td>
			<td></td>
		</tr>
		<tr>
			<td>Microforge</td>
			<td>Narashige</td>
			<td>MF-90</td>
			<td>For electrode polishing.</td>
		</tr>
		<tr>
			<td>N2 Supplement (100x)</td>
			<td>Thermo Fisher Scientific</td>
			<td>17502-048</td>
			<td>additiive to culture medium, for SGN</td>
		</tr>
		<tr>
			<td>NaCl</td>
			<td>Sigma-Aldrich</td>
			<td>S7653</td>
			<td>Additive to internal solution</td>
		</tr>
		<tr>
			<td>NaOH (1 M)</td>
			<td>Thomas Scientific</td>
			<td>319511-500ML</td>
			<td>for titration pH</td>
		</tr>
		<tr>
			<td>Osmometer</td>
			<td>Advanced Instruments Inc.</td>
			<td>3320</td>
			<td></td>
		</tr>
		<tr>
			<td>Oxygen, Medical grade, with adequate regulator and tubing</td>
			<td>USC Material Management</td>
			<td>MEDOX200 (Identifier: 00015)</td>
			<td>for dissolving into dissection and bath solutions</td>
		</tr>
		<tr>
			<td>Parafilm</td>
			<td>Bemis</td>
			<td>PM992</td>
			<td></td>
		</tr>
		<tr>
			<td>Pasteur pipette bulb (3 ml)</td>
			<td>Fisher Scientific</td>
			<td>03-448-25</td>
			<td>bulb for trituration pipettes</td>
		</tr>
		<tr>
			<td>Penicillin/Streptomycin</td>
			<td>Thermo Fisher Scientific</td>
			<td>15140122</td>
			<td>additive to prevent contamination of culture medium</td>
		</tr>
		<tr>
			<td>Pentobarbital based euthanasia solution (e.g., Fatal Plus. 50 &#8211; 60 mg/kg dosing)&#160;</td>
			<td>MWI Animal Health</td>
			<td>15199</td>
			<td>for euthanasia</td>
		</tr>
		<tr>
			<td>PES membrane filters ,&#160; 0.2 micrometer&#160;</td>
			<td>Nalgene</td>
			<td>566-0020</td>
			<td>for filtering solutions</td>
		</tr>
		<tr>
			<td>PES membrane sterile syringe filters, 0.22 um, 30 mm&#160;</td>
			<td>CELLTREAT</td>
			<td>229747</td>
			<td>for filtering solutions drawn into syringes</td>
		</tr>
		<tr>
			<td>Petri dishes, 35 x 10 mm</td>
			<td>Genessee Scientific</td>
			<td>32-103</td>
			<td>for micro dissection and to hold Tip dip solution in perforated-patch configuration</td>
		</tr>
		<tr>
			<td>Petri Dishes, 60 x 15 mm</td>
			<td>Midland Scientific</td>
			<td>P7455</td>
			<td>for gross dissection</td>
		</tr>
		<tr>
			<td>pH Meter</td>
			<td>Mettler Toledo</td>
			<td>Model S20</td>
			<td></td>
		</tr>
		<tr>
			<td>Pipettors (1000, 200, 10) microliter</td>
			<td>USA Scientific</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Poly-d-lysine coated glass bottomed culture dish</td>
			<td>Mattek</td>
			<td>P35GC-0-10-C</td>
			<td>to plate neurons for culture</td>
		</tr>
		<tr>
			<td>Quick change platform, heated base, for 35 mm culture dishes</td>
			<td>Warner Instruments</td>
			<td>64-0375</td>
			<td></td>
		</tr>
		<tr>
			<td>Reference Cell</td>
			<td>World Precision Instruments</td>
			<td>RC1T</td>
			<td></td>
		</tr>
		<tr>
			<td>Scalpel blade</td>
			<td>Miltex</td>
			<td>4-315</td>
			<td></td>
		</tr>
		<tr>
			<td>Scalpel Handle</td>
			<td>Fine Science Tools</td>
			<td>10003-12</td>
			<td></td>
		</tr>
		<tr>
			<td>Scientific Scale</td>
			<td>Mettler Toledo</td>
			<td>XS64</td>
			<td></td>
		</tr>
		<tr>
			<td>Serological Pipettes (10, 25) milliliter</td>
			<td>Fisher Scientific</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Silicone Grease Kit (for sealing coverglass and chamber)</td>
			<td>Warner Instruments</td>
			<td>64-0378</td>
			<td></td>
		</tr>
		<tr>
			<td>Small Animal Guillotine</td>
			<td>Kent Scientific</td>
			<td>DCAP</td>
			<td></td>
		</tr>
		<tr>
			<td>Small animal guillotine</td>
			<td>Kent Scientific</td>
			<td>DCAP</td>
			<td>for decapitation if dissecting rats older than P15.</td>
		</tr>
		<tr>
			<td>Stereo Dissection Microscope&#160;</td>
			<td>Zeiss</td>
			<td>Stemi 2000</td>
			<td></td>
		</tr>
		<tr>
			<td>Straight surgical scissors</td>
			<td>Fine Science Tools</td>
			<td>14060-09</td>
			<td></td>
		</tr>
		<tr>
			<td>Syringe (3, 10, 30) milliliter</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Trypsin</td>
			<td>Sigma Aldrich</td>
			<td>T1426</td>
			<td>one out of three enzyme to digest tissue</td>
		</tr>
		<tr>
			<td>Tuberculin syringe&#160;</td>
			<td>Covidien</td>
			<td>8881500105</td>
			<td>for delivering euthanasia solution by intraperitoneal injection</td>
		</tr>
		<tr>
			<td>Vannas Spring Scissor, 2.5 mm Cutting Edge</td>
			<td>Fine Science Tools</td>
			<td>15000-08</td>
			<td></td>
		</tr>
		<tr>
			<td>Volumetric flask, 1000 milliliter</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Vortex</td>
			<td>VWR</td>
			<td>945300</td>
			<td></td>
		</tr>
		<tr>
			<td>Water, sterile u ltrapure, R&#62;18.18 megaOhms cm (e.g., filtered by a Millipore-Sigma water purification system)</td>
			<td>Millipore-Sigma</td>
			<td>CDUFBI001</td>
			<td></td>
		</tr>
	</tbody>
</table>

isolating and culturing vestibular and spiral ganglion somata from neonatal rodents for patch-clamp recordings

The compact morphology of isolated and cultured inner ear ganglion neurons allows for detailed characterizations of the ion channels and neurotransmitter receptors that contribute to cell diversity across this population. This protocol outlines the steps necessary for successful dissecting, dissociating, and short-term culturing of the somata of inner ear bipolar neurons for the purpose of patch-clamp recordings. Detailed instructions for preparing vestibular ganglion neurons are provided with the necessary modifications needed for plating spiral ganglion neurons. The protocol includes instructions for performing whole-cell patch-clamp recordings in the perforated-patch configuration. Example results characterizing the voltage-clamp recordings of hyperpolarization-activated cyclic nucleotide-gated (HCN)-mediated currents highlight the stability of perforated-patch recording configuration in comparison to the more standard ruptured-patch configuration. The combination of these methods, isolated somata plus perforated-patch-clamp recordings, can be used to study cellular processes that require long, stable recordings and the preservation of intracellular milieu, such as signaling through G-protein coupled receptors.

Running voltage-clamp protocols by applying families of voltage steps reveals the voltage-dependent activation of a variety of different families of currents. Representative examples of whole-cell currents evoked from a VGN and adapted from published recordings13 are shown in Figure 1A,B. Applying depolarizing voltages (Figure 1B) activates an inward current (negative by convention) that activates and inactivates very rap...

Watch this Scientific Journal Video about Isolating and Culturing Vestibular and Spiral Ganglion Somata from Neonatal Rodents for Patch-Clamp Recordings at JoVE.com

Isolating and Culturing Vestibular and Spiral Ganglion Somata from Neonatal Rodents for Patch-Clamp Recordings

Presented here are methods providing detailed instructions for dissecting, dissociating, culturing, and patch-clamp recording from vestibular ganglion and spiral ganglion neurons of the inner ear.

The compact morphology of isolated and cultured inner ear ganglion neurons allows for detailed characterizations of the ion channels and neurotransmitter ...

Many ion channels and neurotransmitter receptors that are found at the terminals of auditory and vestibular afferent neurons are also found at their cell bodies. Cultures of isolated cell bodies can be studied in vitro to understand how these ion channels and receptors influence the responses of the neurons. The compact morphology of the cell bodies allows for high quality electrical recordings to characterize the voltage-dependent properties of the ion channels and neurotransmitter receptors.Moreover, easy access to a wide variety of cell types allows for high throughput by a physical analysis of cell diversity. The procedures will be demonstrated by graduate student Katherine Regalado, along with postdoctoral fellows, Dr.Daniel Bronson and Nathaniel Nowak from my laboratory. To begin hold a glass pasture pipette to the flame of a Bunsen burner to prepare tritration pipettes for cell dissociation.Once the glass tip begins to melt, stretch the glass out to the desired tip diameter. Pull one end of the pipette away from the flame to create a small bend. Place the bent pipette under a microscope.Using a scoring tile, score and break the glass at the desired diameter. Pass the pipette tip over the top of the burner flame. This will quickly polish the rough edges near the tip.Scoop out the brain of the euthanized mouse using closed surgical scissors. Sever and remove the cranial nerve to completely detach the brain from the skull. Starting at the back of the head, pull the clear membranous material off with forceps, and then cut the top of the skull out using surgical scissors.Remove the excess tissue from the back of the head and neck to make the dissection area and otic capsule cleaner and easier to access. Transfer the tissue to a second Petri dish with fresh L-15 solution. Then locate the otic capsule and the auditory, superior, vestibular, and inferior vestibular nerves.Separate the superior and inferior ganglia using small spring scissors and cut away the auditory nerve. Using a scalpel, gently shave off the bony ridge to weaken the bony area under which the nerve dives into the bony capsule. Carefully remove the debris with a scalpel, exposing the entire swollen portion of the ganglion.Use the fine spring scissors to cut and separate the ganglion from the peripheral nerve branch that is diving toward the utricle. Remove the superior ganglion using fine forceps and transfer it to a 35-millimeter Petri dish with fresh L-15 solution. After preheating the enzyme solution, pour the enzyme mixture into a 35-millimeter Petri dish and place it in a 37 degrees Celsius incubator for 10 to 15 minutes.Clean the ganglion using fine forceps and small spring scissors by removing bone, excess tissue, nerve fibers, and any other superfluous structures. Take care to minimize the removal of any ganglionic tissue. Transfer the cleaned ganglia into the preheated enzyme solution and place it back in the incubator for 10 to 40 minutes.Then transfer the ganglia to the 35-millimeter Petri dish with fresh L-15 solution. After two to three minutes, transfer the ganglia to another 35-millimeter Petri dish filled with filtered culture media. Transfer approximately 150 microliters of filtered culture media onto a coated glass bottom dish.Then, transfer the desired number of ganglia to the cover slip. Draw a small amount of culture media from the culture dish and rinse the tritration pipette with medium to prevent the tissue from sticking to the sides of the glass pipette. Triturate by gently and repeatedly passing the tissue through the pipette until the ganglia are sufficiently dissociated.After five minutes, check under a light microscope to see if the cells have settled on the cover slip. Carefully place a culture dish into a 37-degree Celsius incubator for 12 to 24 hours. Next, locate the otic capsule after bisecting the head and extract it from the skull by chipping away at the edges using forceps.The spiral portion of the otic capsule houses the cochlea with the organ of Corti. Chip away at the bone, overlying the cochlear turns with fine forceps parallel to the curve of the bone. Use small spring scissors to sever the modiolus at the base of the cochlea to free it from the rest of the otic capsule.Cut the organ of Corti into two or three turns using small spring scissors such that it lays flat, and excise the modiolus from each turn. Remove the stria vascularis by pinching the stria at the base with fine forceps. Unwind around the spiral and up to the apex to peel it free from the organ of Corti.Remove the spiral ganglion by cutting at the edge of where the spiral ganglion neuron fiber tracts project toward the hair cells and then clean the ganglion as shown earlier. After enzymatically treating the spiral ganglion, tritrate the spiral ganglion in the culture medium supplemented with N2 and B27. Place the culture dish containing the dissociated ganglia in a 37-degree Celsius, 5%carbon dioxide incubator for 12 to 24 hours.Dip the tip of the pipette into the clean solution of the culture dish to fill it with a clean solution that does not contain amphotericin. Fill the back of the pipette with the internal solution containing amphotericin. Dip the tip of the pipette back into the clean solution of the culture dish while the amphotericin slowly enters the tip from the back of the pipette.Next, finish filling the pipette with the amphotericin solution of to two-thirds of the pipette. Lower the pipette into the bath of the recording chamber and locate the pipette tip in the middle of the field of view. Ensure that the tip is free of air bubbles or other debris.Position the pipette close to the membrane and land firmly on the center of the cell. Apply negative pressure or suction using a syringe or mouth pipette. Turn on the holding potential of minus 60 millivolts.The seal resistance should increase until it passes a giga ohm. Once a giga ohm seal forms, release the negative pressure. Before tyrosine begins to work, the input resistance slowly decreases, and the current flowing in response to the five millivolts voltage step, progressively increases as the amphotericin enters the membrane.The representative examples of whole cell currents evoked from a vestibular ganglion neuron are shown in this figure. The net inward sodium currents are identified here by their transient activation and inactivation. The net outward currents are carried largely by potassium ions and have much slower activation and inactivation kinetics than sodium currents.The hyperpolarization activated cyclic nucleotide gated currents, or HCN currents, are activated by a family of long duration hyperpolarizing voltages. The stability of ion channel characterization in the perforated patch at different time points during recording is shown in this figure. The voltage dependent activation curves of HCN currents were measured in a perforated patch configuration.The curve has a sigmoidal shape and was stable throughout a long recording. The relative instability of the ruptured patch mode is illustrated by non-overlapping sigmoidal curves from different time points. The activation curves of HCN currents during a ruptured patch configuration are shown here.The firing patterns in five vestibular ganglion somara, five spiral ganglion neurons, and the corresponding current steps are shown here. This heterogeneity in firing patterns reflects a fundamental diversity in the composition of underlying sodium and potassium channels in both vestibular ganglion neurons and spiral ganglion neurons. To maximize cell survival during this procedure, avoid forming air bubbles, do not overwork the tissue, and allow cells to settle before placing samples into the incubator.Perforated patch clamp enables the study of ion channels that are modulated by cytosolic second messengers, which is critical for investigating the effects of efferent neurotransmitters on ganglion neurons. Patch clamp recordings of these bipolar neurons have been instrumental in revealing how biophysical diversity contributes to functional diversity in sensory neurons.

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Research

JoVE Journal

Neuroscience

986 Views.  University of Southern California. Many ion channels and neurotransmitter receptors that are found at the terminals of auditory and vestibular afferent neurons are also found at their cell bodies. Cultures of isolated cell bodies can be studied in vitro to understand how these ion channels and receptors influence the responses of the neurons. The compact morphology of the cell bodies allows for high quality electrical recordings to characterize the voltage-dependent properties of the ion channels and neurotransmitter receptors...