Name: single-cell electroporation across different organotypic slice culture of mouse hippocampal excitatory and class-specific inhibitory neurons
Uploaded: 2020-10-06T13:30:00
Description: Watch this Scientific Journal Video about Single-Cell Electroporation across Different Organotypic Slice Culture of Mouse Hippocampal Excitatory and Class-Specific Inhibitory Neurons at JoVE.com

This work was supported by National Institutes of Health Grants (R01NS085215 to K.F., T32 GM107000 and F30MH122146 to A.C.). The authors thank Ms. Naoe Watanabe for skillful technical assistance.

All animal protocols were reviewed and approved by the Institutional Animal Care and Use Committee (IACUC) at the University of Massachusetts Medical School. Slice culture preparation, plasmid preparation, and electroporation are also detailed in our previously published methods and can be referred to for additional information10.
1. Slice culture preparation
<ol>
	<li>Prepare mouse organotypic hippocampal slice cultures as previously described11</su...

<ol>
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We describe here an electroporation method that transfects both excitatory and inhibitory neurons with high efficiency and precision. Our optimized electroporation protocol has three innovative breakthroughs to achieve highly efficient gene transfection. Our first modification was to increase pipette size compared with previously published protocols3,5,6. This change enabled us to electroporate many neurons without pipette clogg...

In molecular biology, one of the most important considerations to an investigator is how to deliver a gene of interest into a cell or population of cells to elucidate its function. The different methods of delivery can be categorized as either biological (e.g., a viral vector), chemical (e.g., calcium phosphate or lipid), or physical (e.g., electroporation, microinjection, or biolistics)1,2. Biological methods are highly efficient and can be cell type-specific but are limited by the development of specific genetic tools. Chemical approaches are very powerful in vitro, but transfections are generally random; further, these approaches are mostly reserved for primary cells only. Of the physical approaches, biolistics is the simplest and easiest from a technical point of view, but again produces random transfection results at a relatively low efficiency. For applications which require transfer into specific cells without the need for developing genetic tools, we look toward single-cell electroporation3,4.
Whereas electroporation used to refer only to field electroporation, over the past twenty years, multiple in vitro and in vivo single-cell electroporation protocols have been developed to improve specificity and efficiency5,6,7, demonstrating that electroporation can be used to transfer genes to individual cells and can, therefore, be extremely precise. However, the procedures are technically demanding, time-consuming, and relatively inefficient. Indeed, more recent papers have investigated the feasibility of mechanized electroporation rigs8,9, which can help to eliminate several of these barriers for investigators interested in installing such robotics. But for those looking for simpler means, the problems with electroporation, namely cell death, transfection failure, and pipette clogging, remain a concern.
We recently developed an electroporation method that uses larger-tipped glass pipettes, milder electrical pulse parameters, and a unique pressure cycling step, which generated a much higher transfection efficiency in excitatory neurons than previous methods, and enabled us for the first time to transfect genes in inhibitory interneurons, including somatostatin-expressing inhibitory interneurons in the hippocampal CA1 region of mouse organotypic slice culture10. However, the reliability of this electroporation method in different inhibitory interneuron types and neuronal developmental stages has not been addressed. Here, we demonstrated that this electroporation technique is capable of transfecting genes into both excitatory neurons and different classes of interneurons. Importantly, transfection efficiency was high regardless of days in vitro (DIV) slice culture age tested. This established and user-friendly technique is highly recommended to any investigator interested in using single-cell electroporation for different cell types in the context of in vitro mouse brain tissue.

<table>
	<tbody>
		<tr>
			<td>Plasmid preparation</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Plasmid Purification Kit</td>
			<td>Qiagen</td>
			<td>12362</td>
			<td></td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Organotypic slice culture preparation</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>6 Well Plates</td>
			<td>GREINER BIO-ONE</td>
			<td>657160</td>
			<td></td>
		</tr>
		<tr>
			<td>Dumont #5/45 Forceps</td>
			<td>FST</td>
			<td>#5/45</td>
			<td>Angled dissection forceps for organotypic slice culture preparation</td>
		</tr>
		<tr>
			<td>Flask Filter Unit</td>
			<td>Millipore</td>
			<td>SCHVU02RE</td>
			<td>Filtration and storage of culture media</td>
		</tr>
		<tr>
			<td>Incubator</td>
			<td>Binder</td>
			<td>BD C150-UL</td>
			<td></td>
		</tr>
		<tr>
			<td>McIlwain Tissue Chopper</td>
			<td>TED PELLA, INC.</td>
			<td>10180</td>
			<td>Tissue chopper for organotypic slice culture preparation</td>
		</tr>
		<tr>
			<td>Millicell Cell Culture Insert, 30 mm</td>
			<td>Millipore</td>
			<td>PIHP03050</td>
			<td>Organotypic slice culture inserts</td>
		</tr>
		<tr>
			<td>Osmometer</td>
			<td>Precision Systems</td>
			<td>OSMETTE II</td>
			<td></td>
		</tr>
		<tr>
			<td>PTFE coated spatulas</td>
			<td>Cole-Parmer</td>
			<td>SK-06369-11</td>
			<td></td>
		</tr>
		<tr>
			<td>Scissors</td>
			<td>FST</td>
			<td>14958-09</td>
			<td></td>
		</tr>
		<tr>
			<td>Stereo Microscope</td>
			<td>Olympus</td>
			<td>SZ61</td>
			<td></td>
		</tr>
		<tr>
			<td>Sterile Vacuum Filtration System</td>
			<td>Millipore</td>
			<td>SCGPT01RE</td>
			<td>Filtration and storage of aCSF</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Electrode preparation</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Capillary Glasses</td>
			<td>Warner Instruments</td>
			<td>640796</td>
			<td></td>
		</tr>
		<tr>
			<td>Micropipetter Puller</td>
			<td>Sutter Instrument</td>
			<td>P-1000</td>
			<td>Puller</td>
		</tr>
		<tr>
			<td>Oven</td>
			<td>Binder</td>
			<td>BD (E2)</td>
			<td></td>
		</tr>
		<tr>
			<td>Puller Filament</td>
			<td>Sutter Instrument</td>
			<td>FB330B</td>
			<td>Puller</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Single-cell electroporation and fluorescence imaging #1</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>3.5 mm Falcon Petri Dishes</td>
			<td>BD Falcon</td>
			<td>353001</td>
			<td></td>
		</tr>
		<tr>
			<td>Airtable</td>
			<td>TMC</td>
			<td>63-7512E</td>
			<td></td>
		</tr>
		<tr>
			<td>CCD camera</td>
			<td>Q Imaging</td>
			<td>Retiga-2000DC</td>
			<td>Camera</td>
		</tr>
		<tr>
			<td>Electroporation System</td>
			<td>Molecular Devices</td>
			<td>Axoporator 800A</td>
			<td>Electroporator</td>
		</tr>
		<tr>
			<td>Fluorescence Illumination System</td>
			<td>Prior</td>
			<td>Lumen 200</td>
			<td></td>
		</tr>
		<tr>
			<td>Manipulator</td>
			<td>Sutter Instrument</td>
			<td>MPC-385</td>
			<td>Manipulator</td>
		</tr>
		<tr>
			<td>Metamorph software</td>
			<td>Molecular Devices</td>
			<td></td>
			<td>Image acquisition</td>
		</tr>
		<tr>
			<td>Peristaltic Pump</td>
			<td>Rainin</td>
			<td>Dynamax, RP-2</td>
			<td>Perfusion pump</td>
		</tr>
		<tr>
			<td>Shifting Table</td>
			<td>Luigs &#38; Neuman</td>
			<td>240 XY</td>
			<td></td>
		</tr>
		<tr>
			<td>Speaker</td>
			<td>Unknown</td>
			<td></td>
			<td>Speakers connected to the electroporator</td>
		</tr>
		<tr>
			<td>Stereo Microscope</td>
			<td>Olympus</td>
			<td>SZ30</td>
			<td></td>
		</tr>
		<tr>
			<td>Table Top Incubator</td>
			<td>Thermo Scientific</td>
			<td>MIDI 40</td>
			<td></td>
		</tr>
		<tr>
			<td>Upright Microscope</td>
			<td>Olympus</td>
			<td>BX61WI</td>
			<td></td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Fluorescence imaging #2</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>All-in-One Fluorescence Microscope</td>
			<td>Keyence</td>
			<td>BZ-X710</td>
			<td></td>
		</tr>
	</tbody>
</table>

single-cell electroporation across different organotypic slice culture of mouse hippocampal excitatory and class-specific inhibitory neurons

Electroporation has established itself as a critical method for transferring specific genes into cells to understand their function. Here, we describe a single-cell electroporation technique that maximizes the efficiency (~80%) of in vitro gene transfection in excitatory and class-specific inhibitory neurons in mouse organotypic hippocampal slice culture. Using large glass electrodes, tetrodotoxin-containing artificial cerebrospinal fluid and mild electrical pulses, we delivered a gene of interest into cultured hippocampal CA1 pyramidal neurons and inhibitory interneurons. Moreover, electroporation could be carried out in cultured hippocampal slices up to 21 days in vitro with no reduction in transfection efficiency, allowing for the study of varying slice culture developmental stages. With interest growing in examining the molecular functions of genes across a diverse range of cell types, our method demonstrates a reliable and straightforward approach to in vitro gene transfection in mouse brain tissue that can be performed with existing electrophysiology equipment and techniques.

Our single-cell electroporation is capable of precisely delivering genes into visually identified excitatory and inhibitory neurons. We electroporated three different neuronal cell types at three different time points. Parvalbumin (Pv) or vesicular glutamate type 3 (VGT3) expressing neurons were visualized by crossing Pvcre (JAX #008069) or VGT3cre (JAX #018147) lines with TdTomato (a variant of red fluorescent protein) reporter line (Jax #007905), respectively named Pv/TdTomato and VGT3/TdTomato li...

Watch this Scientific Journal Video about Single-Cell Electroporation across Different Organotypic Slice Culture of Mouse Hippocampal Excitatory and Class-Specific Inhibitory Neurons at JoVE.com

Single-Cell Electroporation across Different Organotypic Slice Culture of Mouse Hippocampal Excitatory and Class-Specific Inhibitory Neurons

Presented here is a protocol for single-cell electroporation that can deliver genes in both excitatory and inhibitory neurons across a range of in vitro hippocampal slice culture ages. Our approach provides precise and efficient expression of genes in individual cells, which can be used to examine cell-autonomous and intercellular functions.

Electroporation has established itself as a critical method for transferring specific genes into cells to understand their function. Here, we describe a ...

Gene transfection is a vital approach for neurobiology studies. Our electroporation technique enables us to transfect gene of interest interneurons in organotypic hippocampus slice culture with no detectable side effects. This protocol has a much higher transfection efficiency compared to other single cell protocols, but it is still relatively inexpensive and simple to perform.This technique will be useful for researchers interested in understanding specific molecular and physiological functions of neurons, including cell autonomous mechanisms and transsynaptic protein interactions. To prepare slice cultures for electroporation, transfer the culture inserts of interest into individual three centimeter petri dishes loaded with 900 microliters of culture medium, and place the cultures in a tabletop carbon dioxide incubator. Next, pre-incubate fresh culture inserts with one milliliter of slice culture medium per insert in a 3.5 centimeter petri dish for at least 30 minutes, and sterilize the lines of the electroporation rig with 10%bleach for five minutes.At the end of the perfusion, rinse the lines with the ionized autoclaved water for at least 30 minutes before perfusing with filter sterilized ACSF containing 0.001 millimolar tetrodotoxin. Set the electroporator pulse to an amplitude of minus five volts, a square pulse, a train of 500 milliseconds, a frequency of 50 hertz, and a pulse width of 500 microseconds. Fill a glass pipette with five microliters of plasmid-containing internal solution, and gently flick and tap the tip multiple times to remove any trapped bubbles.Use a dissection microscope to confirm that the tip is not damaged, and securely attach the pipette tip to the electrode. When the tip makes contact with the ACSF, record the pipette resistance readout of the electroporator. To isolate a slice culture, cut the culture insert membrane with a sharp blade, and use sharp angled forceps to carefully transfer the slice culture to the electroporation chamber.Then fix the culture position with a slice anchor. For electroporation of the cells of interest, apply positive pressure to the pipette by mouth, and use the three-dimensional knob controls to maneuver the pipette tip to near the surface of the slice culture. Viewing the culture with the microscope, approach the target cell with the tip, keeping the positive pressure applied until a dimple forms on the cell surface.Upon visualization of the dimple, quickly apply mild negative pressure by mouth so that a loose seal forms between the pipette tip and the plasma membrane. The membrane will slightly enter the pipette. An approximately 2.5x increase in the initial resistance of the pipette should be observed, as indicated by an increase in tone from the speakers.Quickly reapply positive pressure so that the dimple reforms. Then immediately complete at least two more pressure cycles as just demonstrated without pausing. After the last pressure pulse, hold the negative pressure for one second.When tone from the speakers reaches a stable apex in pitch, use the foot pedal to quickly pulse the electroporator. After the electroporation, gently retract the pipette approximately 100 microns from the cell without applying pressure, and reapply positive pressure, verifying that the resistance is similar to the baseline readout before approaching the next cell. When all of the cells of interest have been electroporated, transfer the slice culture into one of the prepared fresh culture inserts, and place the insert at 35 degrees Celsius for up to three days.In this representative experiment, EGFP was transfected into five to 20 pyramidal neurons in the hippocampal CA1 area across seven, 14, and 21 days in vitro slice culture ages. Parvalbumin and vesicular glutamate type 3 interneurons can also be successfully electroporated within the hippocampal CA1 area. Interestingly, transfection is not significantly affected by the day in vitro slice culture age, and does not differ with the transfection efficiency observed in CA1 pyramidal neurons.Neurons are very fragile. You must be extremely cautious and gentle when approaching and pressure cycling the cells and retracting the pipette tip to causing serious damage. After electroporation, the cells can be subjected to various experimental analysis, including electrophysiology and imaging.

single-cell-electroporation-across-different-organotypic-slice

Research

JoVE Journal

Neuroscience

The Organotypic Hippocampal Slice Culture Model for Examining Neuronal Injury

Organotypic hippocampal slice culture is an in vitro method to examine mechanisms of neuronal injury in which the basic architecture and composition of the hippocampus is relatively preserved 1. The organotypic culture system allows for the examination of neuronal, astrocytic and microglial effects, but as an ex vivo preparation, does not address effects of blood flow, or recruitment of peripheral inflammatory cells. To that end, this culture method is frequently used to examine excitotoxic and hypoxic injury to pyramidal neurons of the hippocampus, but has also been used to examine the inflammatory response. Herein we describe the methods for generating hippocampal slice cultures from postnatal rodent brain, administering toxic stimuli to induce neuronal injury, and assaying and quantifying hippocampal neuronal death.

The organoptypic hippocampal slice culture model is an in vitro model used to examine neuronal injury in a variety of paradigms. In this article, we describe the methods for generating slice cultures and quantifying neuronal injury.

Organotypic hippocampal slice culture is an in vitro method to examine mechanisms of neuronal injury in which the basic architecture and composition of ...

Organotypic Slice Culture of GFP-expressing Mouse Embryos for Real-time Imaging of Peripheral Nerve Outgrowth

For many purposes, the cultivation of mouse embryos ex vivo as organotypic slices is desirable. For example, we employ a transgenic mouse line (tauGFP) in which the enhanced version of the green fluorescent protein (EGFP) is exclusively expressed in all neurons of the developing central and peripheral nervous system1, allowing the possibility to both film the innervation of the forelimb and to manipulate this process with pharmacological and genetic techniques2. The most critical parameter in the successful cultivation of such slice cultures is the method by which the slices are prepared. After extensive testing of a variety of methods, we have found that a vibratome is the best possible device to slice the embryos such that they routinely result in a culture that demonstrates viability over a period of several days, and most importantly, develops in an age-specific manner. For mid-gestation embryos, this includes the normal outgrowth of spinal nerves from the spinal cord and the dorsal root ganglia to their targets in the periphery and the proper determination of skeletal and muscle tissue. 
In this work, we present a method for processing whole embryos of embryonic day (E) E10 to E12 into 300 - 400 micrometer slices for cultivation in a standard tissue culture incubator, which can be studied for up to two days after slice preparation. Critical for the success of this approach is the use of a vibratome to slice each agarose-embedded embryo. This is followed by the cultivation of the slices upon Millicell culture membrane inserts placed upon a small volume of medium, resulting in an interface culture technique. One litter with an average of 7 embryos routinely produces at least 14 slices (2-3 slices of the forelimb region per embryo), which varies slightly due to the age of the embryos as well as to the thickness of the slices. About 80% of the cultured slices show nerve outgrowth, which can be measured througout the culturing period2. Representative results using the tauGFP mouse line are demonstrated.

We present a method to prepare organotypic slices of mid-gestation mouse embryos for the cultivation and time-lapse imaging of peripheral nerve outgrowth.

For many purposes, the cultivation of mouse embryos ex vivo as organotypic slices is desirable. For example, we employ a transgenic mouse line (tauGFP) in ...

Nucleofection and Primary Culture of Embryonic Mouse Hippocampal and Cortical Neurons

Hippocampal and cortical neurons have been used extensively to study central nervous system (CNS) neuronal polarization, axon/dendrite outgrowth, and synapse formation and function. An advantage of culturing these neurons is that they readily polarize, forming distinctive axons and dendrites, on a two dimensional substrate at very low densities. This property has made them extremely useful for determining many aspects of neuronal development. Furthermore, by providing glial conditioning for these neurons they will continue to develop, forming functional synaptic connections and surviving for several months in culture. In this protocol we outline a technique to dissect, culture and transfect embryonic mouse hippocampal and cortical neurons. Transfection is accomplished by electroporating DNA into the neurons before plating via nucleofection. This protocol has the advantage of expressing fluorescently-tagged fusion proteins early in development (~4-8hrs after plating) to study the dynamics and function of proteins during polarization, axon outgrowth and branching. We have also discovered that this single transfection before plating maintains fluorescently-tagged fusion protein expression at levels appropriate for imaging throughout the lifetime of the neuron (&gt; 2 months in culture). Thus, this methodology is useful for studying protein localization and function throughout CNS development with little or no disruption of neuronal function.

This protocol outlines the steps required to dissect, transfect via electroporation and culture mouse hippocampal and cortical neurons. Short-term cultures may be used for studies of axon outgrowth and guidance, while long-term cultures can be used for studies of synaptogenesis and dendritic spine analysis.

Hippocampal and cortical neurons have been used extensively to study central nervous system (CNS) neuronal polarization, axon/dendrite outgrowth, and ...

Organotypic Hippocampal Slice Cultures

The hippocampus, a component of the limbic system, plays important roles in long-term memory and spatial navigation 1. Hippocampal neurons can modify the strength of their connections after brief periods of strong activation. This phenomenon, known as long-term potentiation (LTP) can last for hours or days and has become the best candidate mechanism for learning and memory 2. In addition, the well defined anatomy and connectivity of the hippocampus 3 has made it a classical model system to study synaptic transmission and synaptic plasticity4.
As our understanding of the physiology of hippocampal synapses grew and molecular players became identified, a need to manipulate synaptic proteins became imperative. Organotypic hippocampal cultures offer the possibility for easy gene manipulation and precise pharmacological intervention but maintain synaptic organization that is critical to understanding synapse function in a more naturalistic context than routine culture dissociated neurons methods.
Here we present a method to prepare and culture hippocampal slices that can be easily adapted to other brain regions. This method allows easy access to the slices for genetic manipulation using different approaches like viral infection 5,6 or biolistics 7. In addition, slices can be easily recovered for biochemical assays 8, or transferred to microscopes for imaging 9 or electrophysiological experiments 10.

We describe a method to prepare organotypic hippocampal slices that can be easily adapted to other brain regions. Brain slices are laid on porous membranes and culture media is allowed to form an interface. This method preserves the gross architecture of the hippocampus for up to 2 weeks in culture.

The hippocampus, a component of the limbic system, plays important roles in long-term memory and spatial navigation 1. Hippocampal neurons can modify the ...

Isolation and Culture of Hippocampal Neurons from Prenatal Mice

Primary cultures of rat and murine hippocampal neurons are widely used to reveal cellular mechanisms in neurobiology. By isolating and growing individual neurons, researchers are able to analyze properties related to cellular trafficking, cellular structure and individual protein localization using a variety of biochemical techniques. Results from such experiments are critical for testing theories addressing the neural basis of memory and learning. However, unambiguous results from these forms of experiments are predicated on the ability to grow neuronal cultures with minimum contamination by other brain cell types. In this protocol, we use specific media designed for neuron growth and careful dissection of embryonic hippocampal tissue to optimize growth of healthy neurons while minimizing contaminating cell types (i.e. astrocytes). Embryonic mouse hippocampal tissue can be more difficult to isolate than similar rodent tissue due to the size of the sample for dissection. We show detailed dissection techniques of hippocampus from embryonic day 19 (E19) mouse pups. Once hippocampal tissue is isolated, gentle dissociation of neuronal cells is achieved with a dilute concentration of trypsin and mechanical disruption designed to separate cells from connective tissue while providing minimum damage to individual cells. A detailed description of how to prepare pipettes to be used in the disruption is included. Optimal plating densities are provided for immuno-fluorescence protocols to maximize successful cell culture. The protocol provides a fast (approximately 2 hr) and efficient technique for the culture of neuronal cells from mouse hippocampal tissue.

We provide a protocol for the culture of highly purified hippocampal neurons from prenatal mouse brains without the use of a feeder glial cell layer.

Primary cultures of rat and murine hippocampal neurons are widely used to reveal cellular mechanisms in neurobiology. By isolating and growing individual ...

Primary Culture of Mouse Dopaminergic Neurons

Dopaminergic neurons represent less than 1% of the total number of neurons in the brain. This low amount of neurons regulates important brain functions such as motor control, motivation, and working memory. Nigrostriatal dopaminergic neurons selectively degenerate in Parkinson&#39;s disease (PD). This progressive neuronal loss is unequivocally associated with the motors symptoms of the pathology (bradykinesia, resting tremor, and muscular rigidity). The main agent responsible of dopaminergic neuron degeneration is still unknown. However, these neurons appear to be extremely vulnerable in diverse conditions. Primary cultures constitute one of the most relevant models to investigate properties and characteristics of dopaminergic neurons. These cultures can be submitted to various stress agents that mimic PD pathology and to neuroprotective compounds in order to stop or slow down neuronal degeneration. The numerous transgenic mouse models of PD that have been generated during the last decade further increased the interest of researchers for dopaminergic neuron cultures. Here, the video protocol focuses on the delicate dissection of embryonic mouse brains. Precise excision of ventral mesencephalon is crucial to obtain neuronal cultures sufficiently rich in dopaminergic cells to allow subsequent studies. This protocol can be realized with embryonic transgenic mice and is suitable for immunofluorescence staining, quantitative PCR, second messenger quantification, or neuronal death/survival assessment.

Dopaminergic neurons play a vital regulatory role in the brain. Their loss is associated with Parkinson's disease. In this video, we show how to generate primary cultures of central dopaminergic neurons from embryonic mouse mesencephalon. Such cultures are useful to study the extreme vulnerability of these neurons to various stresses.

Dopaminergic neurons represent less than 1% of the total number of neurons in the brain. This low amount of neurons regulates important brain functions ...

Organotypic Slice Cultures to Study Oligodendrocyte Dynamics and Myelination

NG2 expressing cells (polydendrocytes, oligodendrocyte precursor cells) are the fourth major glial cell population in the central nervous system. During embryonic and postnatal development they actively proliferate and generate myelinating oligodendrocytes. These cells have commonly been studied in primary dissociated cultures, neuron cocultures, and in fixed tissue. Using newly available transgenic mouse lines slice culture systems can be used to investigate proliferation and differentiation of oligodendrocyte lineage cells in both gray and white matter regions of the forebrain and cerebellum. Slice cultures are prepared from early postnatal mice and are kept in culture for up to 1 month. These slices can be imaged multiple times over the culture period to investigate cellular behavior and interactions. This method allows visualization of NG2 cell division and the steps leading to oligodendrocyte differentiation while enabling detailed analysis of region-dependent NG2 cell and oligodendrocyte functional heterogeneity. This is a powerful technique that can be used to investigate the intrinsic and extrinsic signals influencing these cells over time in a cellular environment that closely resembles that found in vivo.

A technique to study NG2 cells and oligodendrocytes using a slice culture system of the forebrain and cerebellum is described. This method allows examination of the dynamics of proliferation and differentiation of cells within the oligodendrocyte lineage where the extracellular environment can be easily manipulated while maintaining tissue cytoarchitecture.

NG2 expressing cells (polydendrocytes, oligodendrocyte precursor cells) are the fourth major glial cell population in the central nervous system. During ...

Paired Whole Cell Recordings in Organotypic Hippocampal Slices

Pair recordings involve simultaneous whole cell patch clamp recordings from two synaptically connected neurons, enabling not only direct electrophysiological characterization of the synaptic connections between individual neurons, but also pharmacological manipulation of either the presynaptic or the postsynaptic neuron. When carried out in organotypic hippocampal slice cultures, the probability that two neurons are synaptically connected is significantly increased. This preparation readily enables identification of cell types, and the neurons maintain their morphology and properties of synaptic function similar to that in native brain tissue. A major advantage of paired whole cell recordings is the highly precise information it can provide on the properties of synaptic transmission and plasticity that are not possible with other more crude techniques utilizing extracellular axonal stimulation. Paired whole cell recordings are often perceived as too challenging to perform. While there are challenging aspects to this technique, paired recordings can be performed by anyone trained in whole cell patch clamping provided specific hardware and methodological criteria are followed. The probability of attaining synaptically connected paired recordings significantly increases with healthy organotypic slices and stable micromanipulation allowing independent attainment of pre- and postsynaptic whole cell recordings. While CA3-CA3 pyramidal cell pairs are most widely used in the organotypic slice hippocampal preparation, this technique has also been successful in CA3-CA1 pairs and can be adapted to any neurons that are synaptically connected in the same slice preparation. In this manuscript we provide the detailed methodology and requirements for establishing this technique in any laboratory equipped for electrophysiology.

Pair recordings are simultaneous whole cell patch clamp recordings from two synaptically connected neurons, enabling precise electrophysiological and pharmacological characterization of the synapses between individual neurons. Here we describe the detailed methodology and requirements for establishing this technique in organotypic hippocampal slice cultures in any laboratory equipped for electrophysiology.

Pair recordings involve simultaneous whole cell patch clamp recordings from two synaptically connected neurons, enabling not only direct ...

The Analysis of Neurovascular Remodeling in Entorhino-hippocampal Organotypic Slice Cultures

Ischemic brain injury is among the most common and devastating conditions compromising proper brain function and often leads to persisting functional deficits in the affected patients. Despite intensive research efforts, there is still no effective treatment option available that reduces neuronal injury and protects neurons in the ischemic areas from delayed secondary death. Research in this area typically involves the use of elaborate and problematic animal models. Entorhino-hippocampal organotypic slice cultures challenged with oxygen and glucose deprivation (OGD) are established in&#160;vitro models which mimic cerebral ischemia. The novel aspect of this study is that changes of the brain blood vessels are studied in addition to neuronal changes and the reaction of both the neuronal compartment and the vascular compartment can be compared and correlated. The methods presented in this protocol substantially broaden the potential applications of the organotypic slice culture approach. The induction of OGD or hypoxia alone can be applied by rather simple means in organotypic slice cultures and leads to reliable and reproducible damage in the neural tissue. This is in stark contrast to the complicated and problematic animal experiments inducing stroke and ischemia in vivo. By broadening the analysis to include the study of the reaction of the vasculature could provide new ways on how to preserve and restore brain functions. The slice culture approach presented here might develop into an attractive and important tool for the study of ischemic brain injury and might be useful for testing potential therapeutic measures aimed at neuroprotection.

A protocol for entorhino-hippocampal organotypic slice cultures, which allows reproducing many aspects of ischemic brain injury, is presented. By studying changes of the neurovasculature in addition to changes in the neurons, this protocol is a versatile tool to study plastic changes in neural tissue after injury.

Ischemic brain injury is among the most common and devastating conditions compromising proper brain function and often leads to persisting functional ...

Organotypic Hippocampal Slice Cultures As a Model to Study Neuroprotection and Invasiveness of Tumor Cells

In organotypic hippocampal slice cultures (OHSC), the morphological and functional characteristics of both neurons and glial cells are well preserved. This model is suitable for addressing different research questions that involve studies on neuroprotection, electrophysiological experiments on neurons, neuronal networks or tumor invasion. The hippocampal architecture and neuronal activity in multisynaptic circuits are well conserved in OHSC, even though the slicing procedure itself initially lesions and leads to formation of a glial scar. The scar formation alters presumably the mechanical properties and diffusive behavior of small molecules, etc. Slices allow the monitoring of time dependent processes after brain injury without animal surgery, and studies on interactions between various brain-derived cell types, namely astrocytes, microglia and neurons under both physiological and pathological conditions. An ambivalent aspect of this model is the absence of blood flow and immune blood cells. During the progression of the neuronal injury, migrating immune cells from the blood play an important role. As those cells are missing in slices, the intrinsic processes in the culture may be observed without external interference. Moreover, in OHSC the composition of the medium-external environment is precisely controlled. A further advantage of this method is the lower number of sacrificed animals compared to standard preparations. Several OHSC can be obtained from one animal making simultaneous studies with multiple treatments in one animal possible. For these reasons, OHSC are well suited to analyze the effects of new protective therapeutics after tissue damage or during tumor invasion. 
The protocol presented here describes a preparation method of OHSC that allows generating highly reproducible, well preserved slices that can be used for a variety of experimental research, like neuroprotection or tumor invasion studies.

Organotypic hippocampal slice cultures (OHSC) represent an in vitro model that simulates the in vivo situation very well. Here we describe a vibratome-based improved slicing protocol to obtain high quality slices for use in assessing the neuroprotective potential of novel substances or the biological behavior of tumor cells.

In organotypic hippocampal slice cultures (OHSC), the morphological and functional characteristics of both neurons and glial cells are well preserved. ...