The authors wish to thank Ina Wolter for her excellent technical assistance. VGAT-Venus transgenic rats were generated by Drs. Y. Yanagawa, M. Hirabayashi and Y. Kawaguchi in National Institute for Physiological Sciences, Okazaki, Japan, using pCS2-Venus provided by Dr. A. Miyawaki.

Ethics Statement: All procedures and animal maintenance were performed in accordance with Institutional guidelines, the German Animal Welfare Act, the European Council Directive 86/609/EEC regarding the protection of animals, and guidelines from local authorities (Berlin, T-0215/11)
1. Preparation of Acute-hippocampal Slices
<ol>
	<li>Take a transgenic rat (17 to 24 day old), expressing the fluorescent Venus/YFP protein under the vGAT promoter, which labels the majority of cortical inhibitor...

<ol>
	<li>Freund, T. F., Buzs&#225;ki, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Interneurons+of+the+hippocampus.">Interneurons of the hippocampus.</a> Hippocampus. 6 (4), 347-470 (1996).</li><li>Meyer, A. H., Katona, I., Blatow, M., Rozov, A., Monyer, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vivo+labeling+of+parvalbumin-positive+interneurons+and+analysis+of+electrical+coupling+in+identified+neurons.">In vivo labeling of parvalbumin-positive interneurons and analysis of electrical coupling in identified neurons.</a> Journal of Neuroscience. 22, 7055-7064 (2002).</li><li>Vida, I., Halasy, K., Szinyei, C., Somogyi, P., Buhl, E. 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S., Soltesz, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bridging+the+cleft+at+GABA+synapses+in+the+brain.">Bridging the cleft at GABA synapses in the brain.</a> Trends Neurosci. 17 (12), 517-525 (1994).</li><li>Bartos, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fast+synaptic+inhibition+promotes+synchronized+gamma+oscillations+in+hippocampal+interneuron+networks.">Fast synaptic inhibition promotes synchronized gamma oscillations in hippocampal interneuron networks.</a> PNAS. 99, 13222-13227 (2002).</li><li>Cobb, S. 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A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Petilla+terminology+nomenclature+of+features+of+GABAergic+interneurons+of+the+cerebral+cortex.">Petilla terminology nomenclature of features of GABAergic interneurons of the cerebral cortex.</a> Nature Review Neurosci. 9, 557-568 (2008).</li><li>Klausberger, T., Somogyi, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neuronal+diversity+and+temporal+dynamics+the+unity+of+hippocampal+circuit+operations.">Neuronal diversity and temporal dynamics the unity of hippocampal circuit operations.</a> Science. 321, 53-57 (2008).</li><li>Buhl, E. 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A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differential+GABAB-Receptor-Mediated+Effects+in+Perisomatic-+and+Dendrite-Targeting+Parvalbumin+Interneurons.">Differential GABAB-Receptor-Mediated Effects in Perisomatic- and Dendrite-Targeting Parvalbumin Interneurons.</a> Journal of Neuroscience. 33 (18), 7961-7974 (2013).</li><li>Uematsu, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+chemical+composition+of+cortical+GABAergic+neurons+revealed+in+transgenic+Venus-expressing+rats.">Quantitative chemical composition of cortical GABAergic neurons revealed in transgenic Venus-expressing rats.</a> Cerebral Cortex. 18, 315-330 (2008).</li><li>Bischofberger, J., Engel, D., Li, L., Geiger, J. R. P., Jonas, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Patch-clamp+recording+from+mossy+fiber+terminals+in+hippocampal+slices.">Patch-clamp recording from mossy fiber terminals in hippocampal slices.</a> Nature Protocols. 1, 2075-2081 (2006).</li><li>Houston, C. M., Bright, D. P., Sivilotti, L. G., Beato, M., Smart, T. 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R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Patch-clamp+recording+in+brain+slices+with+improved+slicer+technology.">Patch-clamp recording in brain slices with improved slicer technology.</a> Pflugers Archives. 443, 491-501 (2002).</li><li>Malinow, R., Tsien, R. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Presynaptic+enhancement+shown+by+whole-cell+recordings+of+long-term+potentiation+in+hippocampal+slices.">Presynaptic enhancement shown by whole-cell recordings of long-term potentiation in hippocampal slices.</a> Nature. 346, 177-180 (1990).</li><li>Vida, I., Bartos, M., Jonas, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Shunting+inhibition+improves+robustness+of+gamma+oscillations+in+hippocampal+interneuron+networks+by+homogenizing+firing+rates.">Shunting inhibition improves robustness of gamma oscillations in hippocampal interneuron networks by homogenizing firing rates.</a> Neuron. 49 (1), 107-117 (2006).</li><li>Neu, A., F&#246;ldy, C., Soltesz, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Postsynaptic+origin+of+CB1-dependent+tonic+inhibition+of+GABA+release+at+cholecystokinin-positive+basket+cell+to+pyramidal+cell+synapses+in+the+CA1+region+of+the+rat+hippocampus.">Postsynaptic origin of CB1-dependent tonic inhibition of GABA release at cholecystokinin-positive basket cell to pyramidal cell synapses in the CA1 region of the rat hippocampus.</a> Journal of Physiology. 578 (1), 233-247 (2007).</li><li>Baude, A., Bleasdale, C., Dalezios, Y., Somogyi, P., Klausberger, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immunoreactivity+for+the+GABAA+receptor+alpha1+subunit,+somatostatin+and+Connexin36+distinguishes+axoaxonic,+basket,+and+bistratified+interneurons+of+the+rat+hippocampus.">Immunoreactivity for the GABAA receptor alpha1 subunit, somatostatin and Connexin36 distinguishes axoaxonic, basket, and bistratified interneurons of the rat hippocampus.</a> Cerebral Cortex. 17, 2094-2107 (2007).</li></ol>

We describe a method which combines electrophysiological and neuroanatomical techniques to functionally characterize morphologically- and neurochemically-identified neurons in vitro; in particular the diverse types of cortical inhibitory INs. Key aspects of the procedure are: (1) pre-selection of potential INs; (2) intracellular recording and neuron visualization; and finally (3) morphological and immunocytochemical analysis of recorded INs. Although this study has addressed PV-INs in particular, the described protocol c...

Hippocampal neuronal circuits have long been the subject of intense scrutiny, with respect to both anatomy and physiology, due to their essential role in learning and memory as well as spatial navigation in both humans and rodents. Equally, the prominent, but simple laminar organization of the hippocampus makes this region a favored subject of studies addressing structural and functional properties of cortical networks.
Hippocampal circuits are comprised of excitatory principal cells (&#62;80%) and a smaller (10-20%), but highly diverse cohort of inhibitory interneurons1-3. Interneurons release &#947;-aminobutyric acid (GABA) from their axon terminals which acts at fast ionotropic GABAA receptors (GABAARs) and slow metabotropic GABAB receptors (GABABRs)4. These inhibitory mechanisms counterbalance excitation and regulate the excitability of principal cells, and thus their timing and pattern of discharge. However, GABA released from interneurons acts not only on principal cells, but also on the interneurons themselves5,6. Pre and postsynaptic receptors mediate feedback regulation and inhibitory mutual interactions among the various types of interneuron. These inhibitory mechanisms in interneuron networks are believed to be central to the generation and shaping of population activity patterns, in particular oscillations at different frequencies7.
Whole-cell patch-clamp recording is a well-established method for the examination of intrinsic properties and synaptic interactions of neurons. However, due to the high diversity of interneuron types, investigation of inhibitory interneurons requires rigorous identification of the recorded cells. As hippocampal interneuron types are characterized by distinct morphological features and neurochemical marker expression, combined anatomical and immunocytochemical examination can provide a means to determine precise interneuron identity6,8,9.
In the present paper we describe an experimental approach in which whole-cell patch-clamp recordings from single neurons or synaptically-coupled pairs are combined with intracellular labeling, followed by post-hoc morphological and immunocytochemical analysis, allowing for the characterization of slow GABAB receptor mediated inhibitory effects in identified interneurons. As an example, we focus on one major type of interneuron, a subset of the so called &#8220;basket cells&#8221; (BC), which innervates the soma and proximal dendrites of its postsynaptic targets and is characterized by a &#8220;fast spiking&#8221; (FS) discharge pattern, an axon densely covering the cell body layer, and expression of the calcium-binding protein parvalbumin (PV)10,11. These interneurons display large postsynaptic inhibitory currents, as well as prominent presynaptic modulation of their synaptic output, in response to GABABR activation12. The combination of techniques described here can be applied equally well to investigate intrinsic or synaptic mechanisms in a variety of other identified neuron types.

<table border="0" cellpadding="0" cellspacing="0" width="725">
	<tbody>
		<tr height="20">
			<td height="20" style="height:20px;width:175px;">Name</td>
			<td style="width:148px;">Company</td>
			<td style="width:152px;">Catalog Number</td>
			<td style="width:251px;">Comments</td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;width:175px;">Transgenic vGAT-venus rats</td>
			<td style="width:148px;">-</td>
			<td style="width:152px;">-</td>
			<td style="width:251px;">see Uematsu et al., 2008</td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;width:175px;">Venus (515&#160;nm) goggles</td>
			<td style="width:148px;">BLS Ltd., Hungary</td>
			<td style="width:152px;">-</td>
			<td style="width:251px;">-</td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;width:175px;">Dissection tools</td>
			<td style="width:148px;">i.e. FST</td>
			<td style="width:152px;">-</td>
			<td style="width:251px;">For brain removal</td>
		</tr>
		<tr height="34">
			<td height="34" style="height:34px;width:175px;">Vibratome</td>
			<td style="width:148px;">Leica</td>
			<td style="width:152px;">VT1200S</td>
			<td style="width:251px;">Or other high end vibratome with minimal vertical oscillation</td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;width:175px;">Slice holding chambers</td>
			<td style="width:148px;">-</td>
			<td style="width:152px;">-</td>
			<td style="width:251px;">Custom-made in lab</td>
		</tr>
		<tr height="34">
			<td height="34" style="height:34px;width:175px;">Upright IR-DIC microscope</td>
			<td style="width:148px;">Olympus, Japan</td>
			<td style="width:152px;">BX50WI</td>
			<td style="width:251px;">With micromanipulator system; i.e. Luigs and Neumann, Kleindiek etc.</td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;width:175px;">CCD camera</td>
			<td style="width:148px;">Till Photonics</td>
			<td style="width:152px;">VX55</td>
			<td style="width:251px;"></td>
		</tr>
		<tr height="34">
			<td height="34" style="height:34px;width:175px;">505 nm LED system</td>
			<td style="width:148px;">Cairn Research</td>
			<td style="width:152px;">OptiLED system</td>
			<td style="width:251px;">Or mercury lamp or other LED system i.e. CooLED.&#160;</td>
		</tr>
		<tr height="34">
			<td height="34" style="height:34px;width:175px;">Multiclamp 700B&#160;</td>
			<td style="width:148px;">Axon Instruments</td>
			<td style="width:152px;"></td>
			<td style="width:251px;">Alternatively 2x Axopatch 200B amplifiers&#160;</td>
		</tr>
		<tr height="34">
			<td height="34" style="height:34px;width:175px;">WinWCP acquisition software</td>
			<td style="width:148px;">John Dempster, Strathclyde University</td>
			<td style="width:152px;">-</td>
			<td style="width:251px;">Any quality acquisition software could be used, i.e. EPHUS, pClamp, Igor etc.&#160;</td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;width:175px;">Electrode Puller</td>
			<td style="width:148px;">Sutter</td>
			<td style="width:152px;">P-97</td>
			<td style="width:251px;">Used with box-filament</td>
		</tr>
		<tr height="34">
			<td height="34" style="height:34px;width:175px;">Borosilicate pipette glass</td>
			<td style="width:148px;">Hilgenberg, Germany</td>
			<td style="width:152px;">1405020</td>
			<td style="width:251px;">2&#160;mm outer, 1&#160;mm inner diameter, no filament</td>
		</tr>
		<tr height="34">
			<td height="34" style="height:34px;width:175px;">Peristaltic pump</td>
			<td style="width:148px;">Gilson</td>
			<td style="width:152px;">Minipuls</td>
			<td style="width:251px;">Other pumps or gravity feed could be used instead</td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;width:175px;">Digital Thermometer</td>
			<td style="width:148px;">-</td>
			<td style="width:152px;">-</td>
			<td style="width:251px;">Custom made</td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;width:175px;">Digital Manometer</td>
			<td style="width:148px;">Supertech, Hungary</td>
			<td style="width:152px;">-</td>
			<td style="width:251px;"></td>
		</tr>
		<tr height="17">
			<td height="34" rowspan="2" style="height:34px;width:175px;">Isolated constant voltage stimulator</td>
			<td rowspan="2" style="width:148px;">Digitimer, Cambridge</td>
			<td rowspan="2" style="width:152px;">DS-2A</td>
			<td rowspan="2" style="width:251px;">-</td>
		</tr>
		<tr height="17">
		</tr>
		<tr height="17">
			<td height="34" rowspan="2" style="height:34px;width:175px;"><a name="RANGE!A19:D34">Biocytin</a></td>
			<td rowspan="2" style="width:148px;">Invitrogen</td>
			<td rowspan="2" style="width:152px;">B1592</td>
			<td rowspan="2">Otherwise known as &#949;-Biotinoyl-L-Lysine&#160;</td>
		</tr>
		<tr height="17">
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;width:175px;">DL-AP5(V) disodium salt</td>
			<td style="width:148px;">Abcam Biochemicals</td>
			<td style="width:152px;">ab120271</td>
			<td style="width:251px;"></td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;width:175px;">DNQX disodium salt</td>
			<td style="width:148px;">Abcam Biochemicals</td>
			<td style="width:152px;">ab120169</td>
			<td style="width:251px;">Alternatively NBQX or CNQX</td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;width:175px;">Gabazine (SR95531)</td>
			<td style="width:148px;">Abcam Biochemicals</td>
			<td style="width:152px;">ab120042</td>
			<td style="width:251px;">Alternatively bicuculline methiodide</td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;width:175px;">R-Baclofen</td>
			<td style="width:148px;">Abcam Biochemicals</td>
			<td style="width:152px;">ab120325</td>
			<td style="width:251px;"></td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;width:175px;">CGP-55,845 hydrochloride</td>
			<td style="width:148px;">Tocris</td>
			<td style="width:152px;">1248</td>
			<td style="width:251px;"></td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;width:175px;">Streptavidin 647</td>
			<td style="width:148px;">Invitrogen</td>
			<td style="width:152px;">S32357</td>
			<td style="width:251px;"></td>
		</tr>
		<tr height="34">
			<td height="34" style="height:34px;width:175px;">anti-PV mouse monoclonal antibody</td>
			<td style="width:148px;">Swant, Switzerland</td>
			<td style="width:152px;">235</td>
			<td style="width:251px;">Working concentration 1:5000-1:10,000</td>
		</tr>
		<tr height="34">
			<td height="34" style="height:34px;width:175px;">anti-mouse secondary antibody&#160;</td>
			<td style="width:148px;">Invitrogen</td>
			<td style="width:152px;">A11030</td>
			<td style="width:251px;">If using Venus or GFP rodent using a red-channel (i.e. 546 nm) is advisable.</td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;width:175px;">Normal Goat Serum</td>
			<td style="width:148px;">Vector Labs</td>
			<td style="width:152px;">S-1000</td>
			<td style="width:251px;"></td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;width:175px;">Microscopy slides</td>
			<td style="width:148px;">-</td>
			<td style="width:152px;">-</td>
			<td style="width:251px;">Any high quality brand&#160;</td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;width:175px;">Glass coverslips</td>
			<td style="width:148px;">-</td>
			<td style="width:152px;">-</td>
			<td style="width:251px;">Usually 22 x 22 mm</td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;width:175px;">Agar spacers</td>
			<td style="width:148px;">-</td>
			<td style="width:152px;">-</td>
			<td style="width:251px;">Agar block, cut on vibratome to 300 &#956;m</td>
		</tr>
		<tr height="34">
			<td height="34" style="height:34px;width:175px;">Laser scanning confocal microscope</td>
			<td style="width:148px;">Olympus, Japan</td>
			<td style="width:152px;">Fluoview FV1000</td>
			<td style="width:251px;">Or other comparable system</td>
		</tr>
		<tr height="17">
			<td height="17" style="height:17px;width:175px;">Fiji (Fiji is just ImageJ)</td>
			<td>http://fiji.sc/Fiji</td>
			<td style="width:152px;">-</td>
			<td style="width:251px;">See Schindelin et al., 2012</td>
		</tr>
	</tbody>
</table>

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.

Provided that slice quality is appreciably good, recording from both CA1 PCs and FS-INs can be achieved with minimal difficulty. The transgenic rat line expressing Venus / YFP under the vGAT promoter13 does not unequivocally identify FS-INs, or indeed BCs. However recordings from INs in and around str. pyramidale, where the density of FS-INs is typically high1, results in a high probability of selecting FS-INs (Figure 2B). FS-INs can be distinguished by their characteristic...

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

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 ...

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JoVE Journal

Neuroscience

24.2K vistas.  Charité Universitätmedizin.  Redes corticales son controlados por un conjunto pequeño, pero diverso de interneuronas inhibidoras. Investigación funcional de interneuronas por lo tanto requiere la grabación específica y la identificación rigurosa. Aquí se describe un enfoque combinado que involucra conjunto de células grabaciones de pares individuales o sinápticamente acoplados de neuronas con el etiquetado intracelular, post-hoc morfológica y inmuno análisis. 