1. Instrumentation 
<ol>
<li>To measure the response of olfactory sensory neurons to photolysis of caged compounds we use a flash lamp in combination with a typical patch-clamp recording system including: a patch-clamp amplifier, a recording electrode and a reference electrode connected to the head-stage of a patch-clamp amplifier, a digitizer, a computer, software for data acquisition, micro-manipulators, an epifluorescence microscope, a perfusion system, an anti-vibration table and a Faraday cage (Figure 2).</li>
<li...

<ol>
	<li>Ellis-Davies, G. C. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Caged+compounds:+photorelease+technology+for+control+of+cellular+chemistry+and+physiology.">Caged compounds: photorelease technology for control of cellular chemistry and physiology.</a> Nat. Methods. 4, 619-628 (2007).</li><li>Pifferi, S., Boccaccio, A., Menini, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cyclic+nucleotide-gated+ion+channels+in+sensory+transduction.">Cyclic nucleotide-gated ion channels in sensory transduction.</a> FEBS Lett. 580, 2853-2859 (2006).</li><li>Bozza, T. C., Kauer, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Odorant+response+properties+of+convergent+olfactory+receptor+neurons.">Odorant response properties of convergent olfactory receptor neurons.</a> J. Neurosci. 18, 4560-4569 (1998).</li><li>Hagen, V., Bendig, J., Frings, S., Eckardt, T., Helm, S., Reuter, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Highly+Efficient+and+Ultrafast+Phototriggers+for+cAMP+and+cGMP+by+Using+Long-Wavelength+UV/Vis-Activation.">Highly Efficient and Ultrafast Phototriggers for cAMP and cGMP by Using Long-Wavelength UV/Vis-Activation.</a> Angew. Chem. Int. Ed. Engl. 40, 1045-1048 (2001).</li><li>Kaplan, J. H., Ellis-Davies, G. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Photolabile+chelators+for+the+rapid+photorelease+of+divalent+cations.">Photolabile chelators for the rapid photorelease of divalent cations.</a> Proc. Natl. Acad. Sci. 85, 6571-6575 (1988).</li><li>Rapp, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flash+lamp-based+irradiation+of+caged+compounds.">Flash lamp-based irradiation of caged compounds.</a> Methods. Enzymol. 291, 202-222 (1998).</li><li>Gurney, A. M., Montenegro, I., Queiros, M. A., Daschbach, J. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flash+photolysis+of+caged+compounds.">Flash photolysis of caged compounds.</a> Microelectrodes: Theory and Applications. , (1991).</li><li>Lagostena, L., Menini, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Whole-cell+recordings+and+photolysis+of+caged+compounds+in+olfactory+sensory+neurons+isolated+from+the+mouse.">Whole-cell recordings and photolysis of caged compounds in olfactory sensory neurons isolated from the mouse.</a> Chem. Senses. 28, 705-716 (2003).</li><li>Boccaccio, A., Lagostena, L., Hagen, V., Menini, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fast+adaptation+in+mouse+olfactory+sensory+neurons+does+not+require+the+activity+of+phosphodiesterase.">Fast adaptation in mouse olfactory sensory neurons does not require the activity of phosphodiesterase.</a> J. Gen. Physiol. 128, 171-184 (2006).</li><li>Boccaccio, A., Menini, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Temporal+development+of+cyclic+nucleotide-gated+and+Ca2++-activated+Cl-+currents+in+isolated+mouse+olfactory+sensory+neurons.">Temporal development of cyclic nucleotide-gated and Ca2+ -activated Cl- currents in isolated mouse olfactory sensory neurons.</a> J. Neurophysiol. 98, 153-160 (2007).</li><li>Sagheddu, C., Boccaccio, A., Dibattista, M., Montani, G., Tirindelli, R., Menini, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Calcium+concentration+jumps+reveal+dynamic+ion+selectivity+of+calcium-activated+chloride+currents+in+mouse+olfactory+sensory+neurons+and+TMEM16B-transfected+HEK+293T+cells.">Calcium concentration jumps reveal dynamic ion selectivity of calcium-activated chloride currents in mouse olfactory sensory neurons and TMEM16B-transfected HEK 293T cells.</a> J. Physiol. 588, 4189-4204 (2010).</li><li>Balana, B., Taylor, N., Slesinger, P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mutagenesis+and+Functional+Analysis+of+Ion+Channels+Heterologously+Expressed+in+Mammalian+Cells.">Mutagenesis and Functional Analysis of Ion Channels Heterologously Expressed in Mammalian Cells.</a> J. Vis. Exp. (44), e2189-e2189 (2010).</li><li>Cygnar, K. D., Stephan, A. B., Zhao, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Analyzing+Responses+of+Mouse+Olfactory+Sensory+Neurons+Using+the+Air-phase+Electroolfactogram+Recording.">Analyzing Responses of Mouse Olfactory Sensory Neurons Using the Air-phase Electroolfactogram Recording.</a> J. Vis. Exp. (37), e1850-e1850 (2010).</li><li>Bernardinelli, Y., Haeberli, C., Chatton, J. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Flash+photolysis+using+a+light+emitting+diode:+an+efficient,+compact,+and+affordable+solution.">Flash photolysis using a light emitting diode: an efficient, compact, and affordable solution.</a> Cell. Calcium. 37, 565-572 (2005).</li></ol>

Flash photolysis of caged compounds combined with patch-clamp recordings is a useful technique to obtain rapid and local jumps in the concentration of physiologically active molecules both inside and outside cells. Several types of caged compounds1 have been synthesized, and this technique can be applied to various types of cells, including cultured cells expressing ion channels that can be activated or modulated by photolysis of some of the available caged compounds11.
Photolysis o...

<table border="1">
		<tbody>
 <tr>
 <th>Equipment</th>
 <th>Company</th>
 <th>Catalogue number</th>
 <th>Comments</th>
 </tr>
 <tr>
 <td>Adapter module flash lamp to microscope</td>
 <td>Rapp OptoElectronic</td>
 <td>FlashCube 70</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Air table</td>
 <td>TMC </td>
 <td>MICRO-g 63-534</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Digitizer</td>
 <td>Axon Instruments </td>
 <td>Digidata 1322A</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Data Acquisition Software</td>
 <td>Axon Instruments</td>
 <td>pClamp 8</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Data Analysis Software</td>
 <td>WaveMetrics</td>
 <td>Igor</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Mirror for adapter module</td>
 <td>Rapp OptoElectronic</td>
 <td>M70/100</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Electrode holder</td>
 <td>Axon Instruments</td>
 <td>1-HL-U</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Faraday&#x2019;s cage</td>
 <td>Custom made</td>
 <td>&nbsp;</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Filter cube</td>
 <td>Olympus</td>
 <td>U-MWU</td>
 <td>Excitation filter removed</td>
 </tr>
 <tr>
 <td>Flash lamp</td>
 <td>Rapp OptoElectronic</td>
 <td>JML-C2</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Forceps Dumont #55 </td>
 <td>World Precision Instruments</td>
 <td>14099</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Glass capillaries </td>
 <td>World Precision Instruments</td>
 <td>PG10165-4</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Glass bottom dish</td>
 <td>World Precision Instruments</td>
 <td>FD35-100</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Illuminator</td>
 <td>Olympus</td>
 <td>Highlight 3100</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Inverted microscope</td>
 <td>Olympus</td>
 <td>IX70</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Micromanipulators </td>
 <td>Luigs &amp; Neumann</td>
 <td>SM I</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Micropipette Puller </td>
 <td>Narishige</td>
 <td>PP-830</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Monitor</td>
 <td>HesaVision</td>
 <td>MTB-01</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Neutral density filters</td>
 <td>Omega Optical</td>
 <td>varies</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Objective 100X</td>
 <td>Zeiss</td>
 <td>Fluar 440285</td>
 <td>Either Zeiss or Olympus </td>
 </tr>
 <tr>
 <td>Objective 100X</td>
 <td>Olympus</td>
 <td>UPLFLN 100XOI2</td>
 <td>Either Zeiss or Olympus</td>
 </tr>
 <tr>
 <td>Optical UV shortpass filter </td>
 <td>Rapp OptoElectronic</td>
 <td>SP400</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Patch-clamp amplifier</td>
 <td>Axon Instruments</td>
 <td>Axopatch 200B</td>
 <td>&nbsp;</td>
 </tr>
					 <tr>
						<td>Photo Diode Assembly </td>
						<td>Rapp OptoElectronic</td>
						<td>PDA</td>
						<td>&nbsp;</td>
					 </tr>
 <tr>
 <td>Quartz light guide</td>
 <td>Rapp OptoElectronic</td>
 <td>varies</td>
 <td>We use 600 &mu;m diameter</td>
 </tr>
 <tr>
 <td>Silver wire</td>
 <td>World Precision Instruments</td>
 <td>AGT1025</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Silver ground pellet</td>
 <td>Warner instruments</td>
 <td>64-1309</td>
 <td>&nbsp;</td>
 </tr>
 <tr>
 <td>Xenon arc lamp</td>
 <td>Rapp OptoElectronic</td>
 <td>XBL-JML</td>
 <td>&nbsp;</td>
 </tr>
 </tbody>
 </table> 
 <table border="1">
 <tbody>
 <tr>
 <th>Reagent</th>
 <th>Company</th>
 <th>Catalogue number</th>
 </tr>
 <tr>
 <td>BCMCM-caged cAMP</td>
 <td>BioLog</td>
 <td>B016</td>
 </tr>
 <tr>
 <td>Bovine serum albumin (BSA)</td>
 <td>Sigma </td>
 <td>A8806</td>
 </tr>
 <tr>
 <td>CaCl2 standard solution 0.1 M</td>
 <td>Fluka </td>
 <td>21059</td>
 </tr>
 <tr>
 <td>Caged Ca: DMNP-EDTA</td>
 <td>Invitrogen </td>
 <td>D6814</td>
 </tr>
 <tr>
 <td>Cysteine</td>
 <td>Sigma </td>
 <td>C9768</td>
 </tr>
 <tr>
 <td>Concanavalin A type V (ConA)</td>
 <td>Sigma </td>
 <td>C7275</td>
 </tr>
 <tr>
 <td>CsCl</td>
 <td>Sigma</td>
 <td>C4036</td>
 </tr>
 <tr>
 <td>DMSO</td>
 <td>Sigma</td>
 <td>D8418</td>
 </tr>
 <tr>
 <td>DNAse I</td>
 <td>Sigma </td>
 <td>D4527</td>
 </tr>
 <tr>
 <td>EDTA</td>
 <td>Sigma </td>
 <td>E9884</td>
 </tr>
 <tr>
 <td>EGTA</td>
 <td>Sigma </td>
 <td>E4378</td>
 </tr>
 <tr>
 <td>Glucose </td>
 <td>Sigma </td>
 <td>G5767</td>
 </tr>
 <tr>
 <td>HEPES</td>
 <td>Sigma </td>
 <td>H3375</td>
 </tr>
 <tr>
 <td>KCl</td>
 <td>Sigma </td>
 <td>P3911</td>
 </tr>
 <tr>
 <td>KOH</td>
 <td>Sigma </td>
 <td>P1767</td>
 </tr>
 <tr>
 <td>Leupeptin </td>
 <td>Sigma </td>
 <td>L0649</td>
 </tr>
 <tr>
 <td>MgCl2</td>
 <td>Fluka </td>
 <td>63020</td>
 </tr>
 <tr>
 <td>Papain</td>
 <td>Sigma </td>
 <td>P3125</td>
 </tr>
 <tr>
 <td>Poly-L-lysine </td>
 <td>Sigma </td>
 <td>P1274</td>
 </tr>
 <tr>
 <td>NaCl</td>
 <td>Sigma </td>
 <td>S9888</td>
 </tr>
 <tr>
 <td>NaOH</td>
 <td>Sigma </td>
 <td>S5881</td>
 </tr>
 <tr>
 <td>NaPyruvate</td>
 <td>Sigma </td>
 <td>P2256</td>
 </tr>
		 </tbody>
</table>

flash photolysis of caged compounds in the cilia of olfactory sensory  neurons

Photolysis of caged compounds allows the production of rapid and localized increases in the concentration of various physiologically active compounds1. Caged compounds are molecules made physiologically inactive by a chemical cage that can be broken by a flash of ultraviolet light. Here, we show how to obtain patch-clamp recordings combined with photolysis of caged compounds for the study of olfactory transduction in dissociated mouse olfactory sensory neurons. The process of olfactory transduction (Figure 1) takes place in the cilia of olfactory sensory neurons, where odorant binding to receptors leads to the increase of cAMP that opens cyclic nucleotide-gated (CNG) channels2. Ca entry through CNG channels activates Ca-activated Cl channels. We show how to dissociate neurons from the mouse olfactory epithelium3 and how to activate CNG channels or Ca-activated Cl channels by photolysis of caged cAMP4 or caged Ca5. We use a flash lamp6,7 to apply ultraviolet flashes to the ciliary region to uncage cAMP or Ca while patch-clamp recordings are taken to measure the current in the whole-cell voltage-clamp configuration8-11.

Watch this Scientific Journal Video about Flash Photolysis of Caged Compounds in the Cilia of Olfactory Sensory  Neurons at JoVE.com

Flash Photolysis of Caged Compounds in the Cilia of Olfactory Sensory  Neurons

Photolysis of caged compounds allows the production of rapid and localized increases in the concentration of various physiologically active compounds. Here, we show how to obtain patch-clamp recordings combined with photolysis of caged cAMP or caged Ca for the study of olfactory transduction in dissociated mouse olfactory sensory neurons.

Photolysis of caged compounds allows the production of rapid and localized increases in the concentration of various physiologically active compounds1. ...

flash-photolysis-caged-compounds-cilia-olfactory-sensory

Research

JoVE Journal

Neuroscience

Analyzing Responses of Mouse Olfactory Sensory Neurons Using the Air-phase Electroolfactogram Recording

Animals depend on olfaction for many critical behaviors, such as finding food sources, avoiding predators, and identifying conspecifics for mating and other social interactions. The electroolfactogram (EOG) recording is an informative, easy to conduct, and reliable method to assay olfactory function at the level of the olfactory epithelium. Since the 1956 description of the EOG by Ottoson in frogs1, the EOG recording has been applied in many vertebrates including salamanders, rabbits, rats, mice, and humans (reviewed by Scott and Scott-Johnson, 2002, ref. 2). The recent advances in genetic modification in mice have rekindled interest in recording the EOG for physiological characterization of olfactory function in knock-out and knock-in mice. EOG recordings have been successfully applied to demonstrate the central role of olfactory signal transduction components3-8, and more recently to characterize the contribution of certain regulatory mechanisms to OSN responses9-12.
Odorant detection occurs at the surface of the olfactory epithelium on the cilia of OSNs, where a signal transduction cascade leads to opening of ion channels, generating a current that flows into the cilia and depolarizes the membrane13. The EOG is the negative potential recorded extracellularly at the surface of the olfactory epithelium upon odorant stimulation, resulting from a summation of the potential changes caused by individual responsive OSNs in the recording field2. Comparison of the amplitude and kinetics of the EOG thus provide valuable information about how genetic modification and other experimental manipulations influence the molecular signaling underlying the OSN response to odor. 
Here we describe an air-phase EOG recording on a preparation of mouse olfactory turbinates. Briefly, after sacrificing the mouse, the olfactory turbinates are exposed by bisecting the head along the midline and removing the septum. The turbinate preparation is then placed in the recording setup, and a recording electrode is placed at the surface of the olfactory epithelium on one of the medial turbinates. A reference electrode is electrically connected to the tissue through a buffer solution. A continuous stream of humidified air is blown over the surface of the epithelium to keep it moist. The vapor of odorant solutions is puffed into the stream of humidified air to stimulate the epithelium. Responses are recorded and digitized for further analysis.

The electroolfactogram (EOG) recording is an informative, easy-to-conduct, and reliable way of assessing olfactory function at the level of the olfactory epithelium. This protocol describes a recording setup, mouse tissue preparation, data collection, and basic data analysis.

Animals depend on olfaction for many critical behaviors, such as finding food sources, avoiding predators, and identifying conspecifics for mating and ...

Live-imaging of PKC Translocation in Sf9 Cells and in Aplysia Sensory Neurons

Protein kinase Cs (PKCs) are serine threonine kinases that play a central role in regulating a wide variety of cellular processes such as cell growth and learning and memory. There are four known families of PKC isoforms in vertebrates: classical PKCs (&alpha;, &beta;I, &beta;II and &gamma;), novel type I PKCs (&#949; and &eta;), novel type II PKCs (&delta; and &theta;), and atypical PKCs (&zeta; and &iota;). The classical PKCs are activated by Ca2+ and diacylclycerol (DAG), while the novel PKCs are activated by DAG, but are Ca2+-independent. The atypical PKCs are activated by neither Ca2+ nor DAG. In Aplysia californica, our model system to study memory formation, there are three nervous system specific PKC isoforms one from each major class, namely the conventional PKC Apl I, the novel type I PKC Apl II and the atypical PKC Apl III. PKCs are lipid-activated kinases and thus activation of classical and novel PKCs in response to extracellular signals has been frequently correlated with PKC translocation from the cytoplasm to the plasma membrane. Therefore, visualizing PKC translocation in real time in live cells has become an invaluable tool for elucidating the signal transduction pathways that lead to PKC activation. For instance, this technique has allowed for us to establish that different isoforms of PKC translocate under different conditions to mediate distinct types of synaptic plasticity and that serotonin (5HT) activation of PKC Apl II requires production of both DAG and phosphatidic acid (PA) for translocation 1-2. Importantly, the ability to visualize the same neuron repeatedly has allowed us, for example, to measure desensitization of the PKC response in exquisite detail 3. In this video, we demonstrate each step of preparing Sf9 cell cultures, cultures of Aplysia sensory neurons have been described in another video article 4, expressing fluorescently tagged PKCs in Sf9 cells and in Aplysia sensory neurons and live-imaging of PKC translocation in response to different activators using laser-scanning microscopy.

In this video, we demonstrate visualization of PKC translocation in living cells using fluorescently tagged PKCs.

Protein kinase Cs (PKCs) are serine threonine kinases that play a central role in regulating a wide variety of cellular processes such as cell growth and ...

Lentivirus-mediated Genetic Manipulation and Visualization of Olfactory Sensory Neurons in vivo

Development of a precise olfactory circuit relies on accurate projection of olfactory sensory neuron (OSN) axons to their synaptic 
targets in the olfactory bulb (OB). The molecular mechanisms of OSN axon growth and targeting are not well understood. Manipulating gene expression and subsequent 
visualizing of single OSN axons and their terminal arbor morphology have thus far been challenging. To study gene function at the single cell level within a specified 
time frame, we developed a lentiviral based technique to manipulate gene expression in OSNs in vivo. Lentiviral particles are delivered to OSNs by microinjection 
into the olfactory epithelium (OE). Expression cassettes are then permanently integrated into the genome of transduced OSNs. Green fluorescent protein expression 
identifies infected OSNs and outlines their entire morphology, including the axon terminal arbor. Due to the short turnaround time between microinjection and 
reporter detection, gene function studies can be focused within a very narrow period of development. With this method, we have detected GFP expression within as 
few as three days and as long as three months following injection. We have achieved both over-expression and shRNA mediated knock-down by lentiviral microinjection. 
This method provides detailed morphologies of OSN cell bodies and axons at the single cell level in vivo, and thus allows characterization of candidate gene function 
during olfactory development.

Lentivirus-mediated Genetic Manipulation and Visualization of Olfactory Sensory Neurons in vivo

We present a lentiviral technique for genetic manipulation and visualization of single olfactory sensory neuron axon and its terminal arborization in vivo.

Development of a precise olfactory circuit relies on accurate projection of olfactory sensory neuron (OSN) axons to their synaptic 
targets in the ...

Intracellular Recording, Sensory Field Mapping, and Culturing Identified Neurons in the Leech, Hirudo medicinalis

The freshwater leech, Hirudo medicinalis, is a versatile model organism that has been used to address scientific questions in the fields of neurophysiology, neuroethology, and developmental biology. The goal of this report is to consolidate experimental techniques from the leech system into a single article that will be of use to physiologists with expertise in other nervous system preparations, or to biology students with little or no electrophysiology experience. We demonstrate how to dissect the leech for recording intracellularly from identified neural circuits in the ganglion. Next we show how individual cells of known function can be removed from the ganglion to be cultured in a Petri dish, and how to record from those neurons in culture. Then we demonstrate how to prepare a patch of innervated skin to be used for mapping sensory or motor fields. These leech preparations are still widely used to address basic electrical properties of neural networks, behavior, synaptogenesis, and development. They are also an appropriate training module for neuroscience or physiology teaching laboratories.

Intracellular Recording, Sensory Field Mapping, and Culturing Identified Neurons in the Leech, Hirudo medicinalis

This article describes three nervous system preparations using leeches: intracellular recording from neurons in ventral ganglia, culturing neurons from ventral ganglia, and recording from a patch of innervated skin to map sensory fields.

The freshwater leech, Hirudo medicinalis, is a versatile model organism that has been used to address scientific questions in the fields of ...

Whole Mount Immunolabeling of Olfactory Receptor Neurons in the Drosophila Antenna

Odorant molecules bind to their target receptors in a precise and coordinated manner. Each receptor recognizes a specific signal and relays this information to the brain. As such, determining how olfactory information is transferred to the brain, modifying both perception and behavior, merits investigation. Interestingly, there is emerging evidence that cellular transduction and transcriptional factors are involved in the diversification of olfactory receptor neuron. Here we provide a robust whole mount immunological labeling method to assay in vivo olfactory receptor neuron organization. Using this method, we identified all olfactory receptor neurons with anti-ELAV antibody, a known pan-neural marker and Or49a-mCD8::GFP, an olfactory receptor neuron specifically expressed in Nba neuron using anti-GFP antibody.

Whole Mount Immunolabeling of Olfactory Receptor Neurons in the Drosophila Antenna

Herein we describe the process of whole mount immunostaining of Drosophila antennae, which enables us to better understand the molecular mechanisms involved in the diversification of olfactory receptor neurons (ORN)s.

Odorant molecules bind to their target receptors in a precise and coordinated manner. Each receptor recognizes a specific signal and relays this ...

Whole Mount Labeling of Cilia in the Main Olfactory System of Mice

The mouse olfactory system comprises 6-10 million olfactory sensory neurons in the epithelium lining the nasal cavity. Olfactory neurons extend a single dendrite to the surface of the epithelium, ending in a structure called dendritic knob. Cilia emanate from this knob into the mucus covering the epithelial surface. The proteins of the olfactory signal transduction cascade are mainly localized in the ciliary membrane, being in direct contact with volatile substances in the environment. For a detailed understanding of olfactory signal transduction, one important aspect is the exact morphological analysis of signaling protein distribution. Using light microscopical approaches in conventional cryosections, protein localization in olfactory cilia is difficult to determine due to the density of ciliary structures. To overcome this problem, we optimized an approach for whole mount labeling of cilia, leading to improved visualization of their morphology and the distribution of signaling proteins. We demonstrate the power of this approach by comparing whole mount and conventional cryosection labeling of Kirrel2. This axon-guidance adhesion molecule is known to localize in a subset of sensory neurons and their axons in an activity-dependent manner. Whole mount cilia labeling revealed an additional and novel picture of the localization of this protein.

Cilia of olfactory sensory neurons contain proteins of the signal transduction cascade, but a detailed spatial analysis of their distribution is difficult in cryosections. We describe here an optimized approach for whole mount labeling and en face visualization of ciliary proteins.

The mouse olfactory system comprises 6-10 million olfactory sensory neurons in the epithelium lining the nasal cavity. Olfactory neurons extend a single ...

Perforated Patch-clamp Recording of Mouse Olfactory Sensory Neurons in Intact Neuroepithelium: Functional Analysis of Neurons Expressing an Identified Odorant Receptor

Analyzing the physiological responses of olfactory sensory neurons (OSN) when stimulated with specific ligands is critical to understand the basis of olfactory-driven behaviors and their modulation. These coding properties depend heavily on the initial interaction between odor molecules and the olfactory receptor (OR) expressed in the OSNs. The identity, specificity and ligand spectrum of the expressed OR are critical. The probability to find the ligand of the OR expressed in an OSN chosen randomly within the epithelium is very low. To address this challenge, this protocol uses genetically tagged mice expressing the fluorescent protein GFP under the control of the promoter of defined ORs. OSNs are located in a tight and organized epithelium lining the nasal cavity, with neighboring cells influencing their maturation and function. Here we describe a method to isolate an intact olfactory epithelium and record through patch-clamp recordings the properties of OSNs expressing defined odorant receptors. The protocol allows one to characterize OSN membrane properties while keeping the influence of the neighboring tissue. Analysis of patch-clamp results yields&#160;a precise quantification of ligand/OR interactions, transduction pathways and pharmacology, OSNs&#39; coding properties and their modulation at the membrane level.&#160;

Analyzing the physiological properties of olfactory sensory neurons still faces technical limitations. Here we record them through perforated patch-clamp in an intact preparation of the olfactory epithelium in gene-targeted mice. This technique allows the characterization of membrane properties and responses to specific ligands of neurons expressing defined olfactory receptors.

Analyzing the physiological responses of olfactory sensory neurons (OSN) when stimulated with specific ligands is critical to understand the basis of ...

Live Imaging of the Ependymal Cilia in the Lateral Ventricles of the Mouse Brain

Multiciliated ependymal cells line the ventricles in the adult brain. Abnormal function or structure of ependymal cilia is associated with various neurological deficits. The current ex vivo live imaging of motile ependymal cilia technique allows for a detailed study of ciliary dynamics following several steps. These steps include: mice euthanasia with carbon dioxide according to protocols of The University of Toledo&#8217;s Institutional Animal Care and Use Committee (IACUC); craniectomy followed by brain removal and sagittal brain dissection with a vibratome or sharp blade to obtain very thin sections through the brain lateral ventricles, where the ependymal cilia can be visualized. Incubation of the brain&#8217;s slices in a customized glass-bottom plate containing Dulbecco&#8217;s Modified Eagle&#8217;s Medium (DMEM)/High-Glucose at 37 &#176;C in the presence of 95%/5% O2/CO2 mixture is essential to keep the tissue alive during the experiment. A video of the cilia beating is then recorded using a high-resolution differential interference contrast microscope. The video is then analyzed frame by frame to calculate the ciliary beating frequency. This allows distinct classification of the ependymal cells into three categories or types based on their ciliary beating frequency and angle. Furthermore, this technique allows the use of high-speed fluorescence imaging analysis to characterize the unique intracellular calcium oscillation properties of ependymal cells as well as the effect of pharmacological agents on the calcium oscillations and the ciliary beating frequency. In addition, this technique is suitable for immunofluorescence imaging for ciliary structure and ciliary protein localization studies. This is particularly important in disease diagnosis and phenotype studies. The main limitation of the technique is attributed to the decrease in live motile cilia movement as the brain tissue starts to die.

Using high-resolution differential interference contrast (DIC) microscopy, an ex vivo observation of the beating of motile ependymal cilia located within the mouse brain ventricles is demonstrated by live-imaging. The technique allows a recording of the unique ciliary beating frequency and beating angle as well as their intracellular calcium oscillation pacing properties.

Multiciliated ependymal cells line the ventricles in the adult brain. Abnormal function or structure of ependymal cilia is associated with various ...

Olfactory Behaviors Assayed by Computer Tracking Of Drosophila in a Four-quadrant Olfactometer

A key challenge in neurobiology is to understand how neural circuits function to guide appropriate animal behaviors. Drosophila melanogaster is an excellent model system for such investigations due to its complex behaviors, powerful genetic techniques, and compact nervous system. Laboratory behavioral assays have long been used with Drosophila to simulate properties of the natural environment and study the neural mechanisms underlying the corresponding behaviors (e.g. phototaxis, chemotaxis, sensory learning and memory)1-3. With the recent availability of large collections of transgenic Drosophila lines that label specific neural subsets, behavioral assays have taken on a prominent role to link neurons with behaviors4-11. Versatile and reproducible paradigms, together with the underlying computational routines for data analysis, are indispensable for rapid tests of candidate fly lines with various genotypes. Particularly useful are setups that are flexible in the number of animals tested, duration of experiments and nature of presented stimuli. The assay of choice should also generate reproducible data that is easy to acquire and analyze. Here, we present a detailed description of a system and protocol for assaying behavioral responses of Drosophila flies in a large four-field arena. The setup is used here to assay responses of flies to a single olfactory stimulus; however, the same setup may be modified to test multiple olfactory, visual or optogenetic stimuli, or a combination of these. The olfactometer setup records the activity of fly populations responding to odors, and computational analytical methods are applied to quantify fly behaviors. The collected data are analyzed to get a quick read-out of an experimental run, which is essential for efficient data collection and the optimization of experimental conditions.

Olfactory Behaviors Assayed by Computer Tracking Of Drosophila in a Four-quadrant Olfactometer

We describe here a behavioral setup and data analysis method for assaying olfactory responses of up to 100 vinegar flies (Drosophila melanogaster). This system may be used with single or multiple olfactory stimuli, and adaptable for optogenetic activation or silencing of neuronal subsets.

A key challenge in neurobiology is to understand how neural circuits function to guide appropriate animal behaviors. Drosophila melanogaster is an ...

Physiological Preparation of Hair Cells from the Sacculus of the American Bullfrog (Rana catesbeiana)

The study of hearing and balance rests upon insights drawn from biophysical studies of model systems. One such model, the sacculus of the American bullfrog, has become a mainstay of auditory and vestibular research. Studies of this organ have revealed how sensory cells hair can actively detect signals from the environment. Because of these studies, we now better understand the mechanical gating and localization of a hair cell&#39;s transduction channels, calcium&#39;s role in mechanical adaptation, and the identity of hair cell currents. This highly accessible organ continues to provide insight into the workings of hair cells. Here we describe the preparation of the bullfrog&#39;s sacculus for biophysical studies on its hair cells. We include the complete dissection procedure and provide specific protocols for the preparation of the sacculus in specific contexts. We additionally include representative results using this preparation, including the calculation of a hair bundle&#39;s instantaneous force-displacement relation and measurement of a bundle&#39;s spontaneous oscillation.

Physiological Preparation of Hair Cells from the Sacculus of the American Bullfrog Rana catesbeiana

The American bullfrog&#39;s (Rana catesbeiana) sacculus permits direct examination of hair-cell physiology. Here the dissection and preparation of the bullfrog&#39;s sacculus for biophysical studies is described. We show representative experiments from these hair cells, including the calculation of a bundle&#39;s force-displacement relation and measurement of its unforced motion.