Authors would like to thank Peter Mombaerts for the generous gift of OR-GFP mice; Anne Lefranc and the CSGA animal facility for excellent animal care. Funding was provided by CNRS through an ATIP and ATIP Plus grants, by Conseil R&#233;gional de Bourgogne (FABER and PARI grants), by Universit&#233; de Bourgogne (BQR program).

Este protocolo segue as diretrizes de cuidados de animais da Université de Bourgogne e foi aprovado pelo comitê de ética Université de Bourgogne. 1. Os animais <ol><li> Use geneticamente camundongos OR-IRES-tauGFP disponíveis no Laboratório Jackson. Estes murganhos foram desenvolvidos no laboratório Dr. Peter Mombaerts &#39;, a fim de analisar a segmentação do axónio e desenvolvimento do sistema olfactivo 19. Por exemplo, a linha MOR23-IRES-tauGFP, o número de ações 006.643, leva o nome oficial estirpe B6; 129P2- Olfr16 tm2Mom / MomJ; Da mesma forma, a linha SR1-IRES-tauGFP, número de estoque 6717 leva o nome oficial B6; 129P2- Olfr124 tm1Mom / MomJ. </li><li> Em relação à idade dos animais: para um melhor resultado do protocolo, utilizar animais entre 2 e 4 semanas de idade. Nesta faixa etária, a dissecção é mais fácil (ossos mais macios, mais firme do epitélio olfatório) e os botões dendríticas são bigger comparar com animais mais velhos. </li></ol> 2. Preparação de eletrodos e Soluções <ol><li> Para as pipetas estimulantes: compra prepulled estimulando pipetas. Caso contrário, prepará-los manualmente. <ol><li> Usando uma chama, dobrar um milímetro seis pipetas de vidro em cerca de 1 cm da ponta. Insira estes seis pipetas além de uma linha reta 7 th em 1,5 centímetros de calor encolher tubulação fortalecer por um orifício. </li><li> Calor encolher o tubo para manter os barris ligados juntos. Anexar um tubo de calor psiquiatra adicional para a outra extremidade dos barris. Puxe este pipeta estimulante, com um puxador de multi-barril. </li><li> Adicione um pouco de cola líquida branca à volta do orifício para fortalecer as pontas dobradas. Deixe secar O / N. </li></ol></li><li> Prepare 1 ou 2 L de solução de Ringer extracelular normal (em mM: NaCl 124, KCl 3, MgSO4 1,3, CaCl2 2, NaHCO3 26, NaH 2 PO 4 1,25, glicose 15; pH 7,6 e 305 mOsm). Mantenha a 4 ° Caté à sua utilização. </li><li> Preparar a solução estoque intracelular (em mM): KCl 70, KOH 53, ácido metanossulfónico 30, EGTA 5, HEPES 10, 70 sacarose; pH 7,2 (KOH) e 310 mOsm. Manter a 4 ° C até à sua utilização. Bom para várias semanas. </li><li> Preparar a solução intracelular de gravação com nistatina extemporaneamente (no último minuto) antes de experimento. <ol><li> Pesar 3 mg de nistatina, adicionar 50 ul de DMSO; vortex 20 seg depois sonicar 2-3 minutos até completamente diluída. </li><li> Adicionar 20 ul de solução de DMSO-de nistatina em 5 ml de solução de reserva intracelular. Vortex 20 seg, depois sonicar 3 min. Conservar esta solução a 4 ° C e proteger da luz direta, nistatina é sensível à luz. Esta solução pode ser utilizada por algumas horas. Substituir todos os dias. </li><li> Uma vez que a preparação epitélio olfativo é sob o microscópio, tirar um pouco dessa solução em uma seringa de 1 ml com uma ponta amarela alongado-chama para preencher os eletrodos; proteger da luz direta. Uma vez que, à TA, a solução nistatinanão é estável; substituir a solução na seringa de 1 mL a cada hora ou mantê-lo em gelo. </li></ol></li><li> Puxe eléctrodos de registo com um puxador de obter longo pescoço e uma pequena ponta (~ 2 mm) com uma resistência de 15-20 mohms com a solução de nistatina interno. </li><li> Preparar a solução odorante em 0,5 M em DMSO sob exaustor; aliquota e manter a -20 ° C até à sua utilização. Diluir odorante em solução de Ringer, até à concentração desejada. Encha a pipeta estimulante. </li></ol> 3. Preparação de epitélio olfatório Nota: os ratos OR-IRES-tauGFP expressar o tauGFP sob o controlo do promotor OU. Nesses camundongos, todos os neurônios que expressam o OR de interesse são marcadas com GFP. Este protocolo é adaptado para as RUP expressos em todas as zonas. No entanto, dissecções e gravações são mais fáceis para as RUP expressas na zona dorsal. <ol><li> Anestesiar os animais por injecção de uma mistura de cetamina e xilazina (150 mg / kg e 10 mg / kg BODy de peso, respectivamente). Decapitação pode ser realizada com uma tesoura afiada para ratos jovens ou com uma guilhotina roedor mantido adequadamente para ratos mais velhos. <ol><li> Usando anel tesouras de dissecção fazer uma incisão medial longitudinal através da pele dorsal. Retire a pele, puxando-o para além. Usando a tesoura, corte as mandíbulas inferiores na articulação da mandíbula. Remover os dentes frontais superiores por um corte coronal paralelo aos dentes. </li><li> Faça um corte coronal da cabeça atrás dos olhos e manter apenas a parte anterior da cabeça. Mergulhá-lo em solução de Ringer gelada para a dissecação sob o âmbito de aplicação. </li></ol></li><li> Dissecar no âmbito: no lado ventral, faça um corte longitudinal ao longo do maxilar superior / os dentes. Cortar os ossos dorsais longitudinalmente, seguindo o lado dorso-lateral da cavidade nasal. Remover a maioria dos ossos e paladar; transferir o septo e o epitélio ligado a ele em oxigenado Ringer a RT. </li><li> Para a dissecção final: Logo antes de iniciar a gravaçãosessão, descascar o epitélio do septo subjacente com uma pinça. Retire o epitélio com uma pinça e com dois cortes 4-5 mm de tesoura (uso microvannas tesoura) na parte anterior do septo onde a adesão é mais forte. <ol><li> Retire cuidadosamente o órgão vomeronasal, cortando-a ao longo da sua ligação ao epitélio dorsal do septo. Transferir o epitélio para uma câmara de registo com a camada da mucosa voltada para cima; mantê-lo liso na câmara com uma harpa. </li></ol></li><li> Câmara de instalar sob um microscópio vertical equipado com óptica de fluorescência e uma câmera sensível. Visualize a preparação na tela do computador com alta ampliação de 40X através de um objetivo de imersão em água (abertura numérica 0,8) e uma ampliação de 2X ou 4X adicional conseguido por uma lente de aumento. Perfundir continuamente oxigenado com Ringer a RT (1-2 mL / min). </li></ol> 4. A gravação da sessão <ol><li> Procurar célula fluorescente: excitar a preparação em 480nm para EGFP, que emite luz no intervalo de 530-550 nm; alvo um botão dendrítica que é fiável visível na fluorescência e sob campo claro. </li><li> Preencha eléctrodo com solução intracelular com nistatina; remover as bolhas batendo suavemente sobre o eletrodo. </li><li> Insira eletrodo no suporte do eléctrodo, aplique pressão positiva na pipeta; A resistência deve ser de 15-20 mohms. </li><li> Traga eletrodo perto do celular; uma vez que a resistência atinge ~ 40 mohms, libere pressão positiva e aplicar uma ligeira pressão negativa para chegar a um gigaseal. </li><li> Uma vez que o selo é atingido, definir o potencial de membrana a cerca de -75 mV; </li><li> Uma vez que a célula se abre, prosseguir com protocolos de estimulação, tratamentos farmacológicos. Para medir a resposta a uma única estimulação odorante, 200-500 ms ficha de actividade espontânea, para estimular a 500 ms e medir a resposta da célula para até 10 seg 13. Para tratamentos farmacológicos, perfundir os agentes farmacológicos naa concentração desejada de 20. </li></ol> Análise 5. Dados <ol><li> Analisar as correntes induzidas por estimulação odorante como se segue: a amplitude máxima, o tempo de subida (tempo necessário para atingir 90% da amplitude máxima, em mseg), a corrente total (área sob a curva em Pas), a hora a 50% (tempo entre o início e o deslocamento da resposta a 50% da amplitude máxima, em mseg). <ol><li> Usando as correntes de pico de transdução (amplitude máxima atingida), em diferentes concentrações, desenhar e ajustar uma curva de resposta à dose utilizando a equação de Hill: Imax = I / (1 ​​+ (K 1/2 / C) n), em que I representa a corrente de pico , Imax a resposta máxima nas concentrações saturantes, K1 / 2 a concentração para a qual metade da resposta máxima foi alcançada, C a concentração do odorante e n o coeficiente de Hill. </li></ol></li><li> Analisar gravações de potencial de membrana em pinça de corrente para a despolarização máxima, o total potencial provocada (área sob a curva em mVsec); registro de atividade spiking espontânea longo de 30 s para um mínimo de gravações; excitabilidade registro através picos gerado pela injeção de correntes (10/05 PA). </li></ol>

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The authors declare that they have no competing financial interest.

A capacidade deste protocolo para monitorar corretamente as propriedades de ORS saudáveis ​​depende muito da qualidade da preparação. Por conseguinte, os passos de dissecação são críticos. Em primeiro lugar, é fundamental prestar atenção à qualidade (pH, osmolaridade), oxigenação e temperatura (gelo-frio, mas não congelado) do meio de dissecção. Em segundo lugar, a manipulação do epitélio com ferramentas de dissecação deve ser tão limitada quanto possível, para evitar danos. Finalmente, é ess...

Neurônios olfatórios (OSN) representam o primeiro passo de percepção olfativa. Localizado no epitélio olfativo que reveste a cavidade nasal nos roedores, eles transformam a informação química dos odores em potenciais de ação enviadas através do seu axônio para o cérebro. Para compreender melhor os mecanismos de codificação olfativas, é necessário caracterizar as propriedades de transdução de membrana e de ORS. Até recentemente, a maioria das técnicas usadas para caracterizar as propriedades de ORS de mamífero foram realizadas em dissociado ORS 1-4. O processo de dissociação usa vários (ou seja, enzimas) processos mecânicos e químicos para libertar os ORS de seu ambiente. Estes processos induzem um baixo número de células disponíveis para as gravações. Este número baixo pode ser ainda mais crítica no caso de células GFP rotulados. Dissociação também remove as interações locais célula-a-célula entre ORS e outras células do epitélio olfactivo, que pode melhorar survival e modulação das propriedades &quot;ORS. A fim de evitar o procedimento de dissociação, uma preparação intacta foi desenvolvido 5. Cada OSN expressa um receptor olfativo (OR) seleccionados a partir de uma grande família multigene 6. Há ~ 1000 RUP expressos no epitélio olfatório principal no mouse. Devido ao grande número de, ou em animais de tipo selvagem, as possibilidades para gravar ORS que expressam o mesmo ou são muito baixos. Para superar estas limitações, os ratinhos alvo do gene estão disponíveis em todas as ORS que expressam um identificado ou estão marcados com uma proteína fluorescente 7-9. Estes ORS marcadas foram usadas para fazer análise funcional em preparações dissociadas 7,10,11 com os inconvenientes mencionados anteriormente. Uma preparação epitélio intacto 5 de camundongos geneticamente marcadas, portanto, contorna essas questões. Ele permite o monitoramento da atividade de ORS expressam RUP definidos com precisão em um ambiente tão perto no vivo possível. Além disso, gravações de patch-clamp de ORS também permitir uma análise precisa das propriedades da membrana, via de transdução de farmacologia, ligando / ou interações. Todos estes tópicos dificilmente podem ser analisadas usando gravações extracelular. Nós usamos essa técnica para monitorar as respostas dos ORS que expressam os receptores olfativos SR1 e MOR23 12,13. A viabilidade da técnica foi confirmada por outros grupos em MOR23 expressam ORS 14, bem como em outras RUP neurónios que expressam 15,16. O controlo de uma população definida de ORS pode levar à análise das suas propriedades em muitos contextos diferentes, tais como o desenvolvimento 14, 17 envelhecimento, odorante induzida plasticidade 18, e o papel de variações na sequência do receptor olfactivo, em odor de codificação 15. Este protocolo proporciona assim uma ferramenta poderosa para monitorizar as propriedades funcionais de ORS definidas ao nível da membrana.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td colspan="4">heavy equipment</td>
		</tr>
		<tr>
			<td>vibration table with Faraday cage</td>
			<td>TMC</td>
			<td>63-500 SERIES</td>
			<td>required : isolates the recording system from vibrations induced by the environment (movements of experimenter, vibrations of equipment such as fans for cooling computers, etc); can also be purchased with a Faraday cage, or equipped by a custom made Faraday cage; this cage is recommended to avoid electric noise from the environment</td>
		</tr>
		<tr>
			<td colspan="4">optics</td>
		</tr>
		<tr>
			<td>microscope</td>
			<td>Olympus</td>
			<td>BX51WI</td>
			<td>upright microcope equipped with epifluorescence; fixed or moving stage depending on the user&#39;s preference</td>
		</tr>
		<tr>
			<td>objectives</td>
			<td>Olympus</td>
			<td>LUMPLFL40XW</td>
			<td>at least 2 objectives required: a 4x or 10x for coarse approach to the cell; and a 40x immersion long distance example Olympus LUMPLFL40XW/IR/0,8/WD:3.3 MM</td>
		</tr>
		<tr>
			<td>magnifier</td>
			<td>Olympus</td>
			<td>U-TVCAC</td>
			<td>ABSOLUTELY REQUIRED: placed in the light path between the objective and the camera; allows to magnify the image on the screen in order to reach precisely the knob with the recording electrode</td>
		</tr>
		<tr>
			<td>camera</td>
			<td>Olympus</td>
			<td>DP72</td>
			<td>a good camera is required to see the neurons in fluorescence as well as in bright field; the controlling software is simple and allows to take pictures and do live camera image to monitor the approach of the electrode to the cell. An ultrasensitive camera is not necessary</td>
		</tr>
		<tr>
			<td>filters</td>
			<td>Olympus/Chroma</td>
			<td></td>
			<td>depending on the fluorescent protein used in the mice; example for GFP: excitation : BP460-490: emission: HQ530/50m</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td colspan="4">recording electrodes /system</td>
		</tr>
		<tr>
			<td>amplifier</td>
			<td>HEKA</td>
			<td>EPC10 USB</td>
			<td>monitors the currents flowing through the recording electrode and also controls the puffing by sending a TTL signal to the spritzer; the EPC10 setup is controled by computer</td>
		</tr>
		<tr>
			<td>software</td>
			<td>HEKA</td>
			<td>Patchmaster</td>
			<td>controls the amplifier during the experiment</td>
		</tr>
		<tr>
			<td>micromanipulator</td>
			<td>Sutter</td>
			<td>MP225</td>
			<td>precision micromanipulator, allows precise movements down to 1/1Oth of a micrometer; this model is very stable; avoid hydraulic manipulators that may drift</td>
		</tr>
		<tr>
			<td>electrode puller</td>
			<td>sutter</td>
			<td>P97</td>
			<td>with a FT345-B wide trough filament;&#160; to prepare recording pipets of about 2&#181;m diameter with a long tip to reach the cells; the resistance should be 15 to 20Mohm with perforated patch clamp solution</td>
		</tr>
		<tr>
			<td>glass</td>
			<td>sutter</td>
			<td>BF120-69-10</td>
			<td>in our recording conditions, this glass is ideal for recording pipets</td>
		</tr>
		<tr>
			<td>recording chamber</td>
			<td>warner instruments</td>
			<td>RC-26G</td>
			<td>a chamber is needed to set the preparation under the microscope. To maintain the preparation in the center of the chamber, a net/anchor should be used.</td>
		</tr>
		<tr>
			<td colspan="4">stimulation</td>
		</tr>
		<tr>
			<td>glass</td>
			<td>WPI</td>
			<td>TW100F-4</td>
			<td>attached in groups of 7, these pipettes are used to prepare prepulled stimulating pipettes</td>
		</tr>
		<tr>
			<td>multibarrel puller</td>
			<td>MDI</td>
			<td>PMP-107-Z</td>
			<td>by association of pull and twist, this puller allows us to prepare puffing electrodes with 7 barrels</td>
		</tr>
		<tr>
			<td>precision pressure injector&#160;</td>
			<td>Toohey Company</td>
			<td>P/N T25-1-900 Single Channel&#160;&#160;&#160;</td>
			<td>this precision pressure injector&#160; controls the pressure ejected in the multibarrel puller; it is controlled manually or by the amplifier by a 5V&#160; TTLs</td>
		</tr>
		<tr>
			<td>micromanipulator</td>
			<td>Narishige</td>
			<td>YOU-1</td>
			<td>a coarse manipulator is enough to bring the puffing electrode close to the recording site</td>
		</tr>
		<tr>
			<td>tubings</td>
			<td>N/A</td>
			<td></td>
			<td>tygon tubing to bring the pressure from the puffer to the puffing pipette</td>
		</tr>
		<tr>
			<td colspan="4">solutions/perfusion/chemicals</td>
		</tr>
		<tr>
			<td>vacuum pump</td>
			<td>gardner denver</td>
			<td>300 series</td>
			<td>a vibrating membrane pump is more quiet and efficient than other types of pumps</td>
		</tr>
		<tr>
			<td>perfusion system</td>
			<td>N/A</td>
			<td>N/A</td>
			<td>gravity perfusion system with polyethlylen tubing to bring in and out the external solution from the recording chamber</td>
		</tr>
		<tr>
			<td>nystatin</td>
			<td>Sigma-Aldrich</td>
			<td>N3503</td>
			<td>mandatory to perpare internal solution for perforated patch clamp</td>
		</tr>
		<tr>
			<td>DIMETHYL SULFOXIDE</td>
			<td>Sigma-Aldrich</td>
			<td>D5879</td>
			<td>used to disolve nystatin for internal solution for perforated patch&#160;</td>
		</tr>
		<tr>
			<td>Sodium chloride</td>
			<td>Sigma-Aldrich</td>
			<td>S9625</td>
			<td>extracellular solution</td>
		</tr>
		<tr>
			<td>Potassium chloride</td>
			<td>Sigma-Aldrich</td>
			<td>P4504</td>
			<td>intracellular/extracellular solution</td>
		</tr>
		<tr>
			<td>Calcium chloride di hydrate</td>
			<td>Sigma-Aldrich</td>
			<td>C7902</td>
			<td>extracellular solution</td>
		</tr>
		<tr>
			<td>Sodium phosphate monobasic monohydrate (NaH2PO4)</td>
			<td>Sigma-Aldrich</td>
			<td>S9638</td>
			<td>extracellular solution</td>
		</tr>
		<tr>
			<td>Magnesium sulfate heptahydrate (MgSO4 7H2O)</td>
			<td>Sigma-Aldrich</td>
			<td>63140</td>
			<td>extracellular solution</td>
		</tr>
		<tr>
			<td>Glucose</td>
			<td>Sigma-Aldrich</td>
			<td>G8270</td>
			<td>extracellular solution</td>
		</tr>
		<tr>
			<td>Sodium bicarbonate</td>
			<td>Sigma-Aldrich</td>
			<td>S6297</td>
			<td>extracellular solution</td>
		</tr>
		<tr>
			<td>EGTA (Ethylene glycol-bis(2-aminoethylether)-N,N,N&#8242;,N&#8242;-tetraacetic acid)</td>
			<td>Sigma-Aldrich</td>
			<td>E3889</td>
			<td>internal solution</td>
		</tr>
		<tr>
			<td>Potassium hydroxyde</td>
			<td>Sigma-Aldrich</td>
			<td>P1767</td>
			<td>internal solution</td>
		</tr>
		<tr>
			<td>MethylSulfoxide</td>
			<td>Sigma-Aldrich</td>
			<td>47,135-6</td>
			<td>intracellular solution</td>
		</tr>
		<tr>
			<td>Hepes-Na</td>
			<td>Sigma-Aldrich</td>
			<td>H7006</td>
			<td>intracellular solution</td>
		</tr>
		<tr>
			<td>Sucrose</td>
			<td>Sigma-Aldrich</td>
			<td>S0389</td>
			<td>intracellular solution</td>
		</tr>
	</tbody>
</table>

perforated patch-clamp recording of mouse olfactory sensory neurons in intact neuroepithelium: functional analysis of neurons expressing an identified odorant receptor

Analisando as respostas fisiológicas de neurônios olfatórios (OSN) quando estimulados com ligantes específicos é fundamental para compreender a base dos comportamentos olfativos-driven e sua modulação. Estas propriedades de codificação dependem muito da interação inicial entre as moléculas de odor e do receptor olfativo (OR) expressa nas ORS. A identidade, especificidade e ligando espectro da expressa ou são críticos. A probabilidade de encontrar o ligando do ou expresso em um OSN escolhido aleatoriamente dentro do epitélio é muito baixo. Para responder a este desafio, este protocolo utiliza ratinhos geneticamente marcadas que expressam a proteína fluorescente GFP sob o controlo do promotor de RUP definidos. ORS estão localizadas no epitélio apertado e organizada que reveste a cavidade nasal, com as células vizinhas influenciar a sua maturação e função. Aqui nós descrevemos um método para isolar um epitélio olfativo intacta e gravar através de gravações de patch-clamp as propriedades de ORS expressing receptores olfativos definidos. O protocolo permite que um para caracterizar as propriedades de membrana OSN, mantendo a influência do tecido vizinho. A análise dos resultados de patch-clamp produz uma quantificação precisa de ligando / ou interações, vias de transdução e farmacologia, propriedades de codificação &#39;ORS e sua modulação em nível da membrana.

O resultado deste protocolo depende da qualidade da dissecção. A dissecção passos deve ser curto (menos do que 10 a 15 min) e preciso (isto é, para evitar danos do epitélio). A figura 1 ilustra como uma preparação ideal parece em diferentes níveis de ampliação. Numa ampliação baixa sob condições de campo brilhante os diferentes tipos de células (tais como botões de células ORS, apoiando) são distinguíveis (Figura 1A). Ao mais alto nível de ampliação, norm...

Watch this Scientific Journal Video about Perforated Patch-clamp Recording of Mouse Olfactory Sensory Neurons in Intact Neuroepithelium: Functional Analysis of Neurons Expressing an Identified Odorant

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

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.

Perfurado gravação patch-clamp de rato Olfactory neurônios sensoriais na Intact neuroepitélio: Análise Funcional do Neurônios Expressando uma Odorant Receptor Identificados

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

perforated-patch-clamp-recording-mouse-olfactory-sensory-neurons

Research

JoVE Journal

Neuroscience

26.6K visualizações.  Université de Bourgogne. 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.

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

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.

Respostas análise de rato Olfactory neurônios sensoriais Usando a gravação Electroolfactogram Air fase

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

Neurociência

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.

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.

Flash Fotólise de Compostos Caged no Cilia de Olfactory neurônios sensoriais

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

Odorant-induced Responses Recorded from Olfactory Receptor Neurons using the Suction Pipette Technique

Animals sample the odorous environment around them through the chemosensory systems located in the nasal cavity. Chemosensory signals affect complex behaviors such as food choice, predator, conspecific and mate recognition and other socially relevant cues. Olfactory receptor neurons (ORNs) are located in the dorsal part of the nasal cavity embedded in the olfactory epithelium. These bipolar neurons send an axon to the olfactory bulb (see Fig. 1, Reisert &amp; Zhao1, originally published in the Journal of General Physiology) and extend a single dendrite to the epithelial border from where cilia radiate into the mucus that covers the olfactory epithelium. The cilia contain the signal transduction machinery that ultimately leads to excitatory current influx through the ciliary transduction channels, a cyclic nucleotide-gated (CNG) channel and a Ca2+-activated Cl- channel (Fig. 1). The ensuing depolarization triggers action potential generation at the cell body2-4.
In this video we describe the use of the "suction pipette technique" to record odorant-induced responses from ORNs. This method was originally developed to record from rod photoreceptors5 and a variant of this method can be found at jove.com modified to record from mouse cone photoreceptors6. The suction pipette technique was later adapted to also record from ORNs7,8. Briefly, following dissociation of the olfactory epithelium and cell isolation, the entire cell body of an ORN is sucked into the tip of a recording pipette. The dendrite and the cilia remain exposed to the bath solution and thus accessible to solution changes to enable e.g. odorant or pharmacological blocker application. In this configuration, no access to the intracellular environment is gained (no whole-cell voltage clamp) and the intracellular voltage remains free to vary. This allows the simultaneous recording of the slow receptor current that originates at the cilia and fast action potentials fired by the cell body9. The difference in kinetics between these two signals allows them to be separated using different filter settings. This technique can be used on any wild type or knockout mouse or to record selectively from ORNs that also express GFP to label specific subsets of ORNs, e.g. expressing a given odorant receptor or ion channel.

Olfactory receptor neurons (ORNs) convert odor signals first into a receptor current that in turn triggers action potentials that are conveyed to second order neurons in the olfactory bulb. Here we describe the suction pipette technique to record simultaneously the odorant-induced receptor current and action potentials from mouse ORNs.

Odorante induzidas respostas registradas a partir de neurônios receptores olfativos utilizando a técnica de sucção da pipeta

Animals sample the odorous environment around them through the chemosensory systems located in the nasal cavity. Chemosensory signals affect complex ...

Retrograde Fluorescent Labeling Allows for Targeted Extracellular Single-unit Recording from Identified Neurons In vivo

The overall goal of this method is to record single-unit responses from an identified population of neurons. In vivo electrophysiological recordings from individual neurons are critical for understanding how neural circuits function under natural conditions. Traditionally, these recordings have been performed 'blind', meaning the identity of the recorded cell is unknown at the start of the recording. Cellular identity can be subsequently determined via intracellular1, juxtacellular2 or loose-patch3 iontophoresis of dye, but these recordings cannot be pre-targeted to specific neurons in regions with functionally heterogeneous cell types. Fluorescent proteins can be expressed in a cell-type specific manner permitting visually-guided single-cell electrophysiology4-6. However, there are many model systems for which these genetic tools are not available. Even in genetically accessible model systems, the desired promoter may be unknown or genetically homogenous neurons may have varying projection patterns. Similarly, viral vectors have been used to label specific subgroups of projection neurons7, but use of this method is limited by toxicity and lack of trans-synaptic specificity. Thus, additional techniques that offer specific pre-visualization to record from identified single neurons in vivo are needed. Pre-visualization of the target neuron is particularly useful for challenging recording conditions, for which classical single-cell recordings are often prohibitively difficult8-11. The novel technique described in this paper uses retrograde transport of a fluorescent dye applied using tungsten needles to rapidly and selectively label a specific subset of cells within a particular brain region based on their unique axonal projections, thereby providing a visual cue to obtain targeted electrophysiological recordings from identified neurons in an intact circuit within a vertebrate CNS.
The most significant novel advancement of our method is the use of fluorescent labeling to target specific cell types in a non-genetically accessible model system. Weakly electric fish are an excellent model system for studying neural circuits in awake, behaving animals12. We utilized this technique to study sensory processing by "small cells" in the anterior exterolateral nucleus (ELa) of weakly electric mormyrid fish. "Small cells" are hypothesized to be time comparator neurons important for detecting submillisecond differences in the arrival times of presynaptic spikes13. However, anatomical features such as dense myelin, engulfing synapses, and small cell bodies have made it extremely difficult to record from these cells using traditional methods11, 14. Here we demonstrate that our novel method selectively labels these cells in 28% of preparations, allowing for reliable, robust recordings and characterization of responses to electrosensory stimulation.

Retrograde Fluorescent Labeling Allows for Targeted Extracellular Single-unit Recording from Identified Neurons In vivo

Retrograde transport of fluorescent dye labels a sub-population of neurons based on anatomical projection. Labeled axons can be visually targeted in vivo, permitting extracellular recording from identified axons. This technique facilitates recording when neurons cannot be labeled through genetic manipulation or are difficult to isolate using 'blind' in vivo approaches.

Labeling fluorescentes retrógrada Permite alvejado Extracelular Gravação Single-unidade dos neurônios identificados<em&gt; In vivo</em

The overall goal of this method is to record single-unit responses from an identified population of neurons. In vivo electrophysiological recordings from ...

Recording Electrical Activity from Identified Neurons in the Intact Brain of Transgenic Fish

Understanding the cell physiology of neural circuits that regulate complex behaviors is greatly enhanced by using model systems in which this work can be performed in an intact brain preparation where the neural circuitry of the CNS remains intact. We use transgenic fish in which gonadotropin-releasing hormone (GnRH) neurons are genetically tagged with green fluorescent protein for identification in the intact brain. Fish have multiple populations of GnRH neurons, and their functions are dependent on their location in the brain and the GnRH gene that they express1 . We have focused our demonstration on GnRH3 neurons located in the terminal nerves (TN) associated with the olfactory bulbs using the intact brain of transgenic medaka fish (Figure 1B and C). Studies suggest that medaka TN-GnRH3 neurons are neuromodulatory, acting as a transmitter of information from the external environment to the central nervous system; they do not play a direct role in regulating pituitary-gonadal functions, as do the well-known hypothalamic GnRH1 neurons2, 3 .The tonic pattern of spontaneous action potential firing of TN-GnRH3 neurons is an intrinsic property4-6, the frequency of which is modulated by visual cues from conspecifics2 and the neuropeptide kisspeptin 15. In this video, we use a stable line of transgenic medaka in which TN-GnRH3 neurons express a transgene containing the promoter region of Gnrh3 linked to enhanced green fluorescent protein7 to show you how to identify neurons and monitor their electrical activity in the whole brain preparation6.

In this video, we will demonstrate how to record electrical activity from identified single neurons in a whole brain preparation, which preserves complex neural circuits. We use transgenic fish in which gonadotropin-releasing hormone (GnRH) neurons are genetically tagged with a fluorescent protein for identification in the intact brain preparation.

Registro da atividade elétrica dos neurônios identificados no cérebro intacto de peixes transgénicos

Understanding the cell physiology of neural circuits that regulate complex behaviors is greatly enhanced by using model systems in which this work can be ...

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

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

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

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

Isolamento de neurônios sensoriais de<em&gt; Aplysia californica</em&gt; Para Remendo Recordings Grampo de Correntes glutamatérgicos

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

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.

Intracelular de gravação, Sensorial Campo Mapping, e cultivando neurônios identificados nos Sanguessuga, Hirudo medicinalis</i

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.

Monte todo imunomarcação de Neurônios Receptores Olfatórios no<em&gt; Drosophila</em&gt; Antena

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

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

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

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

Gravação Light-provocou respostas pós-sinápticos nos neurônios em Dark-adaptados, Preparações da retina do rato fatia usando técnicas Grampo patch

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

Preparations and Protocols for Whole Cell Patch Clamp Recording of Xenopus laevis Tectal Neurons

The Xenopus tadpole retinotectal circuit, comprised of the retinal ganglion cells (RGCs) in the eye which form synapses directly onto neurons in the optic tectum, is a popular model to study how neural circuits self-assemble. The ability to carry out whole cell patch clamp recordings from tectal neurons and to record RGC-evoked responses, either in vivo or using a whole brain preparation, has generated a large body of high-resolution data about the mechanisms underlying normal, and abnormal, circuit formation and function. Here we describe how to perform the in vivo preparation, the original whole brain preparation, and a more recently developed horizontal brain slice preparation for obtaining whole cell patch clamp recordings from tectal neurons. Each preparation has unique experimental advantages. The in vivo preparation enables the recording of the direct response of tectal neurons to visual stimuli projected onto the eye. The whole brain preparation allows for the RGC axons to be activated in a highly controlled manner, and the horizontal brain slice preparation allows recording from across all layers of the tectum.

Preparations and Protocols for Whole Cell Patch Clamp Recording of Xenopus laevis Tectal Neurons

In this paper, we discuss three brain preparations used for whole cell patch clamp recording to study the retinotectal circuit of Xenopus laevis tadpoles. Each preparation, with its own specific advantages, contributes to the experimental tractability of the Xenopus tadpole as a model to study neural circuit function.

Preparações e protocolos para toda célula Patch Clamp gravação de neurônios Tectal Xenopus laevis

The Xenopus tadpole retinotectal circuit, comprised of the retinal ganglion cells (RGCs) in the eye which form synapses directly onto neurons in the optic ...