Agradecemos Manfred Heckmann para discussões úteis durante o estabelecimento do método. Além disso, agradecemos a Claudia Sommer para assistência técnica e Frank Schubert para o apoio a produção do vídeo. O trabalho foi apoiado pelo Ministério Federal da Educação e Pesquisa (BMBF), na Alemanha, FKZ: 01EO1002 e do Centro Interdisciplinar de Pesquisa Clínica (IZKF) do Hospital Universitário de Jena.

Todos os procedimentos experimentais mencionados no seguinte protocolo foi aprovado pelas autoridades do estado da Turíngia (Thüringer Landesamt für Verbraucherschutz, Reg.-Nr. 02-044/12). 1. Preparativos para Experiment <ol><li> Fabricação de eletrodos de sucção <ol><li> Puxe uma micropipeta usando um capilar de vidro de borosilicato de fábrica com um puxador de micropipeta, por exemplo, um eletrodo de patch padrão. </li><li> Freio o eletrodo de ponta diâmetro de 0,5-1 mm (um pouco maior do que o diâmetro das raízes dorsais), usando um arquivo de diamante. </li><li> Polonês de calor na ponta para que ele não irá prejudicar a raiz dorsal quando ele é sugado dentro Uma tocha do laboratório padrão será adequado. </li><li> Montar o filamento de vidro sobre um suporte de eléctrodo ligada a uma seringa por meio do qual a pressão negativa pode ser aplicada. </li></ol></li><li> Preparação de soluções <ol><li> Injeção de anestesia para ratos: Misturar 0,75 ml de cetamina 10%, 0,24 ml de xilazina 2% aond 5 ml 0,9% de soro fisiológico. 10 mL / g de peso corporal (BW) da solução será injectado por via intraperitoneal (ip). </li><li> Fluido cerebroespinal artificial (ACSF): Dilui-se em água destilada duas vezes os seguintes sais (em mM): NaCl 134; KCl 3, KH 2 PO 4 1,25; MgSO4 • H 2 O 2, NaHCO3 25, CaCl2 2, D- glicose 10. Adicionar H 2 O 2 a uma concentração final de 0,003%. Use solução sempre preparados na hora. </li></ol></li><li> Preparação de a configuração de gravação (Figura 2) <ol><li> Ligue o amplificador a uma interface de PC para a digitalização de dados. </li><li> Use um programa baseado em PC ou um temporizador analógico para acionar um estimulador de pulso quadrado e aquisição de dados no disco rígido do PC. </li><li> Use silverwires clorada conectados à porta eletrodos de vidro padrão como para a estimulação e gravação. </li><li> Montar três manipuladores de estimulação, gravação e eletrodo de referência, respectivamente, em torno de um stereQuadro otactic para ratinhos, de modo a que todos os eléctrodos de ter acesso à medula espinal preparada posteriormente. </li><li> Conecte tubulações e seringas para os detentores de eletrodo a ser maçã para aplicar pressão negativa. </li></ol></li></ol> 2. Comentários Gerais para Experimentação Animal e Preparação Animal para Procedimento de gravação <ol><li> Realizar todos os experimentos com ratos de acordo com as diretrizes da respectiva comissão cuidados com os animais institucional e uso. Realize todas as cirurgias e gravações sob anestesia profunda, garantindo que o sofrimento animal é minimizado. </li><li> Anestesiar os animais por injecção ip de cetamina / xilazina (125 mg e 8 mg por g de peso corporal de cetamina e xilazina, respectivamente, 10 mL / g de peso corporal de solução preparada como descrito acima). Se necessário durante as gravações de longo prazo, injeções adicionais podem ser feitas ip ou im Nota: im injecções repetitivas de 0,05-0,1 ml de solução de cetamina / xilazina na parte superior das coxas têm provado ser adequadospara manter o animal durante a anestesia profunda durante até 3 horas. </li><li> Use veterinário pomada nos olhos para evitar a secura sob anestesia. </li><li> Fixe a cabeça do animal em um quadro estereotáxico e usar uma almofada de aquecimento com sonda retal e loop reflexo para controlar a temperatura do corpo do animal durante o experimento. A fixação da medula espinhal em uma estrutura estereotáxica não é necessário. </li><li> Antes de iniciar a preparação, verifique a profundidade da narcose por reflexo piscar de olhos e se contorcendo entre os dedos dos ratos. Reflexos deve ser abolido. </li><li> Abra a pele ao longo da linha mediana da medula espinal acima do nível superior do tórax para diminuir áreas lombares para obter um campo operacional claro usando um bisturi. Não use a tesoura para fazer incisões na pele. Afrouxar cuidadosamente a pele do tecido subjacente. Durante as etapas subsequentes de manter a ferida humedecidos em 0,9% de solução salina. </li><li> Corte tendões e tecido conjuntivo em ambos os lados das vértebras da lombar para os níveis torácicos usando bisturi e tesoura. </li&gt; <li> Remover os processos espinhosos e resto de tecido conjuntivo em torno das vértebras com uma pequena pinça. </li><li> Cuidadosamente quebrar vértebras com a pinça a partir de níveis lombares (L4/L5) sob um microscópio de dissecação. Enfiar a ponta da pinça, no espaço entre as vértebras e a medula espinal e levantar pedaços de osso distante. Não danificar a dura-máter e evitar a pressão para a medula espinhal. Ambos são críticos para o sucesso. Manter a medula espinhal humedecido durante todo o procedimento. Prossiga para níveis de meados de tórax. </li></ol> 3. A separação de raízes dorsais e DRP Gravação (Figura 2) <ol><li> Abra a dura-máter com cuidado usando uma agulha fina (30 g) com uma ponta dobrada. Use aCSF para umedecer a partir de agora. </li><li> Separa-se as raízes dorsais, tanto quanto possível, utilizando o medidor e cortar duas raízes adjacentes como distal possível. Vigorosa puxando as raízes durante a separação afecta o sucesso da experiência. </li><li> Abaixe o eletrodo de sucção para baixo para o fazerRsal raízes. Adicionar tanto ACSF para a medula espinhal possível porque o líquido auxilia a chupar nas raízes dorsais. </li><li> Chupar a extremidade cortada de uma raiz dorsal em uma pipetas de vidro pela aplicação de pressão negativa por meio de uma seringa. Se necessário, passar da raiz dorsal, em frente da abertura do eléctrodo utilizando uma agulha fina. </li><li> Se a raiz dorsal fica seco no interior do eletrodo de sucção, adicione um pouco aCSF a sua ponta, enquanto cuidadosamente sugando até que a pipeta está suficientemente preenchido com aCSF. </li><li> Depois da raiz dorsal é sugado, levantar a ponta do eletrodo a partir da medula espinhal. Tome cuidado para que não &quot;ponte de água&quot; entre a ponteira ea medula espinhal de curto-circuito do eletrodo de gravação / estimulação. </li><li> Repita os passos de 3,3-3,6 para uma raiz adjacente ipsilateral. </li><li> Posicione o eletrodo de referência mais próximo possível às raízes dorsais e mantê-lo úmido, aplicando aCSF. </li><li> Ao estabelecer a configuração de gravação, uma raiz já está escolhido para a estimulação, ooutra para gravação. O aumento gradual da tensão durante a gravação da segunda raiz dorsal é feito no modo braçadeira atual. Pode-se notar uma deflexão para baixo curto, que é seguido por um, de longa duração deflexão ascendente lento representando o DRP. </li><li> Ajuste a tensão de estímulo à supramáximos níveis e gravar várias varreduras (pelo menos 20 - 30 varreduras / raiz dorsal de 0,1 Hz, filtro entre 0,3 Hz-3 kHz). </li><li> Grave comboios curtos de três estímulos (100 Hz) para obter informações sobre o somatório tempo-dependente do DRP. </li><li> Mudar de gravação e local de estimulação para gravações contralateral adicionais. </li><li> Os animais não têm a intenção de sobreviver ao processo. Sacrificar animais após a última gravação por decapitação, ainda sob anestesia profunda (cetamina / xilazina, veja acima, o passo 2.2). </li></ol> 4. Análise de Dados <ol><li> Transferência de dados para programa de análise (por exemplo, Sigma Plot, Igor Pro, ou MATLAB). </li><li> Calcular média traços from 20-30 varreduras. </li><li> Leve a amplitude máxima de deformação da tensão (a partir da linha de base; DRP amplitude do pico), para posterior análise (Figura 3). </li><li> Calcula-se a razão entre a amplitude de pico de DRP após três pulsos e pulso único para obter uma medida do tempo de soma dependente de potenciais subsequentes. </li></ol>

<ol>
	<li>Eccles, J. C., Eccles, R. M., Magni, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Central+inhibitory+action+attributable+to+presynaptic+depolarization+produced+by+muscle+afferent+volleys.">Central inhibitory action attributable to presynaptic depolarization produced by muscle afferent volleys.</a> J. Physiol. 159, 147-166 (1961).</li><li>Levy, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+role+of+gaba+in+primary+afferent+depolarization.">The role of gaba in primary afferent depolarization.</a> Prog. Neurobiol. 9, 211-267 (1977).</li><li>Eccles, J. C., Magni, F., Willis, W. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Depolarization+of+central+terminals+of+Group+I+afferent+fibres+from+muscle.">Depolarization of central terminals of Group I afferent fibres from muscle.</a> J. Physiol. 160, 62-93 (1962).</li><li>Eccles, J. C., Schmidt, R., Willis, W. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pharmacological+Studies+on+Presynaptic+Inhibition.">Pharmacological Studies on Presynaptic Inhibition.</a> J. Physiol. 168, 500-530 (1963).</li><li>Maxwell, D. J., Bannatyne, B. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrastructure+of+muscle+spindle+afferent+terminations+in+lamina+VI+of+the+cat+spinal+cord.">Ultrastructure of muscle spindle afferent terminations in lamina VI of the cat spinal cord.</a> Brain Res. 288, 297-301 (1983).</li><li>Barber, R. P., Vaughn, J. E., Saito, K., McLaughlin, B. J., Roberts, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=GABAergic+terminals+are+presynaptic+to+primary+afferent+terminals+in+the+substantia+gelatinosa+of+the+rat+spinal+cord.">GABAergic terminals are presynaptic to primary afferent terminals in the substantia gelatinosa of the rat spinal cord.</a> Brain Res. 141, 35-55 (1978).</li><li>Wall, P. D., Lidierth, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Five+sources+of+a+dorsal+root+potential:+their+interactions+and+origins+in+the+superficial+dorsal+horn.">Five sources of a dorsal root potential: their interactions and origins in the superficial dorsal horn.</a> J. Neurophysiol. 78, 860-871 (1997).</li><li>Rudomin, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+search+of+lost+presynaptic+inhibition.">In search of lost presynaptic inhibition.</a> Exp. Brain Res. 196, 139-151 (2009).</li><li>Rudomin, P., Schmidt, R. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Presynaptic+inhibition+in+the+vertebrate+spinal+cord+revisited.">Presynaptic inhibition in the vertebrate spinal cord revisited.</a> Exp. Brain Res. 129, 1-37 (1999).</li><li>Kullmann, D. 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=Presynaptic,+extrasynaptic+and+axonal+GABAA+receptors+in+the+CNS:+where+and+why?.">Presynaptic, extrasynaptic and axonal GABAA receptors in the CNS: where and why?.</a> Prog. Biophys. Mol. Biol. 87, 33-46 (2005).</li><li>Hochman, S., Shreckengost, J., Kimura, H., Quevedo, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Presynaptic+inhibition+of+primary+afferents+by+depolarization:+observations+supporting+nontraditional+mechanisms.">Presynaptic inhibition of primary afferents by depolarization: observations supporting nontraditional mechanisms.</a> Ann. N.Y. Acad. Sci. 1198, 140-152 (2010).</li><li>Thompson, S. W., Wall, P. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+effect+of+GABA+and+5-HT+receptor+antagonists+on+rat+dorsal+root+potentials.">The effect of GABA and 5-HT receptor antagonists on rat dorsal root potentials.</a> Neurosci. Lett. 217, 153-156 (1996).</li><li>Enriquez-Denton, M., Manjarrez, E., Rudomin, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Persistence+of+PAD+and+presynaptic+inhibition+of+muscle+spindle+afferents+after+peripheral+nerve+crush.">Persistence of PAD and presynaptic inhibition of muscle spindle afferents after peripheral nerve crush.</a> Brain Res. 1027, 179-187 (2004).</li><li>Wall, P. D., Devor, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+effect+of+peripheral+nerve+injury+on+dorsal+root+potentials+and+on+transmission+of+afferent+signals+into+the+spinal+cord.">The effect of peripheral nerve injury on dorsal root potentials and on transmission of afferent signals into the spinal cord.</a> Brain Res. 209, 95-111 (1981).</li><li>Witschi, 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=Presynaptic+&#945;2-GABAA+Receptors+in+Primary+Afferent+Depolarization+and+Spinal+Pain+Control.">Presynaptic &#945;2-GABAA Receptors in Primary Afferent Depolarization and Spinal Pain Control.</a> J. Neurosci. 31, 8134-8142 (2011).</li><li>Calancie, B., 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=Evidence+that+alterations+in+presynaptic+inhibition+contribute+to+segmental+hypo-+and+hyperexcitability+after+spinal+cord+injury+in.">Evidence that alterations in presynaptic inhibition contribute to segmental hypo- and hyperexcitability after spinal cord injury in.</a> 89, 177-186 (1993).</li><li>Geis, C., 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=Stiff+person+syndrome-associated+autoantibodies+to+amphiphysin+mediate+reduced+GABAergic+inhibition.">Stiff person syndrome-associated autoantibodies to amphiphysin mediate reduced GABAergic inhibition.</a> Brain. 133, 3166-3180 (2010).</li><li>Geis, C., 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=Human+IgG+directed+against+amphiphysin+induces+anxiety+behavior+in+a+rat+model+after+intrathecal+passive+transfer.">Human IgG directed against amphiphysin induces anxiety behavior in a rat model after intrathecal passive transfer.</a> J. Neural Transm. 119 (8), 981-985 (2012).</li><li>Barron, D. H., Matthews, B. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+interpretation+of+potential+changes+in+the+spinal+cord.">The interpretation of potential changes in the spinal cord.</a> J. Physiol. 92, 276-321 (1938).</li><li>Schmidt, R. F., Trautwein, W., Zimmermann, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dorsal+root+potentials+evoked+by+natural+stimulation+of+cutaneous+afferents.">Dorsal root potentials evoked by natural stimulation of cutaneous afferents.</a> Nature. 212, 522-523 (1966).</li><li>Eccles, J. C., Schmidt, R. F., Willis, W. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Presynaptic+inhibition+of+the+spinal+monosynaptic+reflex+pathway.">Presynaptic inhibition of the spinal monosynaptic reflex pathway.</a> J. Physiol. 161, 282-297 (1962).</li><li>Manjarrez, E., Rojas-Piloni, J. G., Jimenez, I., Rudomin, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modulation+of+synaptic+transmission+from+segmental+afferents+by+spontaneous+activity+of+dorsal+horn+spinal+neurones+in+the+cat.">Modulation of synaptic transmission from segmental afferents by spontaneous activity of dorsal horn spinal neurones in the cat.</a> J. Physiol. 529 Pt 2, 445-460 (2000).</li><li>Geis, C., 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=Human+Stiff-Person+Syndrome+IgG+Induces+Anxious+Behavior+in+Rats.">Human Stiff-Person Syndrome IgG Induces Anxious Behavior in Rats.</a> PLoS One. 6, e16775 (2011).</li><li>Martinez-Gomez, J., Lopez-Garcia, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrophysiological+and+pharmacological+characterisation+of+ascending+anterolateral+axons+in+the+in+vitro+mouse+spinal+cord.">Electrophysiological and pharmacological characterisation of ascending anterolateral axons in the in vitro mouse spinal cord.</a> J. Neurosci. Methods. 146, 84-90 (2005).</li></ol>

Os autores declaram não haver interesses financeiros concorrentes.

Registros eletrofisiológicos extra e intracelulares de atividade neuronal e potenciais sinápticos in vivo são o estado da arte das técnicas de investigação de funções neuronais do sistema nervoso central e fisiopatologia. Spinal integração é fundamental para o funcionamento do motor, por exemplo, os movimentos dos membros e para a percepção sensorial multimodal. Inibição pré-sináptica é um mecanismo fundamental neste processo computacional garantindo respostas adequadas aos estímulos...

A inibição pré-sináptica é um dos mais poderosos mecanismos de inibição na espinal medula. Inibe potenciais pós-sinápticos excitatórios (EPSPS) em motoneurónios monosynaptically excitado sem alterar o potencial da membrana pós-sináptica e a excitabilidade de neurónios motores 1-3. Despolarização aferente primário (PAD) induzida por GABAergic sinapses axo-axonal em fibras pré-sinápticas sensoriais é o mecanismo subjacente 4-7 (ver também Figura 1A). Essas sinapses contêm GABA A e GABA-B (receptores GABA A e GABA B R R). A actividade do GABA R conduz a um aumento da condutância de cloreto que provoca PAD, devido à distribuição de iões local. Esta despolarização bloqueia a propagação dos potenciais de ação nos terminais do axônio e reduz a sua força levando a uma diminuição da Ca 2 +-influxo e uma redução da liberação do transmissor. A ativação dos receptores GABA B não fazt contribuir para PAD, mas leva a uma redução de Ca 2 +-influxo reforçando assim a inibição pré-sináptica. Enquanto a activação de receptores GABA A R parece estar envolvido na inibição de curto prazo, o GABA B R estão envolvidos na modulação de longo prazo de 8-10. Além de GABA, que representa a maior parte do PAD e inibição pré-sináptica, outros sistemas transmissores também pode modular e contribuir para este mecanismo 11,12. As alterações patológicas na inibição pré-sináptica parece ser crucial em vários estados de doença, por exemplo, inflamação e dor neuropática periférica 13,14, bem como anormal processamento da dor central 15, lesão medular 16, e doença do SNC com hiperexcitabilidade motora mediada pela transmissão gabaérgica defeituoso 17, 18. Assim, a estimativa inibição pré-sináptica a pena investigar patologias experimentais no nível da medula espinhal in vivo </em&gt;. PAD dá origem a volumes conduzidos potenciais fornecem uma medida directa da inibição pré-sináptica na medula espinal. Esses potenciais são chamados potenciais de raiz dorsal (DRP) e pode ser medido a partir de raízes dorsal da coluna vertebral após a estimulação das raízes dorsais adjacentes 7. As primeiras medidas de DRP foram relatados em gatos e sapos 19 e foram intensamente estudado em gatos por Eccles, Schmidt, e outros no início dos anos 1970 3,4,20,21. Enquanto in vivo gravações de DRP em gatos 22 e 23 ratos foram amplamente usadas, as medidas em ratinhos foram realizados quase exclusivamente em preparações isoladas ex vivo da medula espinhal 15,24. Aqui, descrevemos um método para gravar DRP em ratos anestesiados in vivo, permitindo uma medida direta da inibição pré-sináptica no organismo intacto.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>Glass tubing (inner diameter 1.16 mm)</td>
			<td>Science Products (Hofheim, Germany)</td>
			<td>GB200F-10</td>
			<td>Other glass tubing might also be suitable</td>
		</tr>
		<tr>
			<td>Superfusion solution (sterile, 0,9% NaCl)</td>
			<td>Braun Melsungen AG&#160;</td>
			<td>3570350</td>
			<td></td>
		</tr>
		<tr>
			<td>(Melsungen, Germany)</td>
		</tr>
		<tr>
			<td>Rompun 2% (Xylazine)</td>
			<td>Bayer Animal Health GmbH (Leverkusen, Germany)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Ketamin 10%</td>
			<td>Medistar GmbH (Ascheberg, Germany)</td>
			<td>KETAMIN 10%</td>
			<td></td>
		</tr>
		<tr>
			<td>30G micro needle/ Sterican</td>
			<td>Braun Melsungen AG&#160;</td>
			<td>4656300</td>
			<td></td>
		</tr>
		<tr>
			<td>(Melsungen, Geramny)</td>
		</tr>
		<tr>
			<td>Salts for aCSF</td>
			<td>Sigma-Aldrich&#160;</td>
			<td>Diverse</td>
			<td></td>
		</tr>
		<tr>
			<td>S88 Dual Output Square Pulse</td>
			<td>Grass Technologies (Warwick, USA)</td>
			<td>S88X</td>
			<td></td>
		</tr>
		<tr>
			<td>Stimulator</td>
		</tr>
		<tr>
			<td>SIU5 RF Transformer Isolation Unit</td>
			<td>Grass Technologies (Warwick, USA)</td>
			<td>SIU-V</td>
			<td></td>
		</tr>
		<tr>
			<td>InstruTECH LIH 8+8</td>
			<td>HEKA (Lambrecht, Deutschland)</td>
			<td>LIH 8+8 + Patchmaster software</td>
			<td></td>
		</tr>
		<tr>
			<td>Data acquisition&#160;</td>
		</tr>
		<tr>
			<td>Universal amplifier</td>
			<td>npi (Tamm, Deutschland)</td>
			<td>ELC-03X</td>
			<td></td>
		</tr>
		<tr>
			<td>Micropipette puller</td>
			<td>Sutter Instruments (Novato, USA)</td>
			<td>P-1000</td>
			<td></td>
		</tr>
		<tr>
			<td>Dissecting microscope</td>
			<td>Olympus (Tokyo, Japan)</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Micromanipulator</td>
			<td>Sutter Instruments (Novato, USA)</td>
			<td>MPC-200/MPC-325</td>
			<td>Mechanical micromanipulators also possible</td>
		</tr>
		<tr>
			<td>Homeothermic Blanket System</td>
			<td>Stoelting (Wood Dale, USA)</td>
			<td>50300V</td>
			<td></td>
		</tr>
		<tr>
			<td>Intra-/extracellular recording electrode holder</td>
			<td>Harvard Apparatus (Holliston, USA)</td>
			<td>641227</td>
			<td></td>
		</tr>
	</tbody>
</table>

measuring spinal presynaptic inhibition in mice by dorsal root potential recording in vivo

A inibição pré-sináptica é um dos mais poderosos mecanismos de inibição na espinal medula. O mecanismo fisiológico subjacente é uma despolarização das fibras aferentes primários mediadas por GABAergic sinapses axo-axonal (despolarização aferente primário). A força de despolarização aferente primário pode ser medido por registo dos potenciais conduzida de volume na raiz dorsal (potenciais de raiz dorsal, DRP). As alterações patológicas de inibição pré-sináptica são cruciais para o processamento central anormal de determinadas condições de dor e em alguns transtornos de hiperexcitabilidade motor. Aqui, descrevemos um método de gravação DRP in vivo em camundongos. A preparação das raízes dorsais da medula espinhal do animal anestesiado eo procedimento de gravação usando eletrodos de sucção são explicados. Este método permite medir GABAergic DRP e, assim, estimar a inibição pré-sináptica da medula em ratos vivos. Em combinação com os modelos de camundongos transgênicos, a gravação DRP pode serve como uma ferramenta poderosa para investigar associada à doença da coluna vertebral fisiopatologia. In vivo gravação tem várias vantagens em relação ao ex vivo preparações medulares isoladas, por exemplo, a possibilidade de gravação ou manipulação de redes supra-e indução de DRP por estimulação de nervos periféricos simultâneos.

Vestígios de DRP típicos são mostrados na Figura 3. O destaque artefato estimulação é geralmente seguido por uma deflexão para baixo curto. Posteriormente um, de longa duração deflexão ascendente lento, representando o DRP é claramente distinguíveis. Num subgrupo de gravações, reflexos de raiz dorsal são visíveis como pequenos picos no topo da DRP. Em camundongos normais do tipo selvagem, os reflexos da raiz dorsal aparecem mais frequentemente quando a tensão estimulação excessiva. Co...

Watch this Scientific Journal Video about Measuring Spinal Presynaptic Inhibition in Mice By Dorsal Root Potential Recording In Vivo at JoVE.com

Measuring Spinal Presynaptic Inhibition in Mice By Dorsal Root Potential Recording In Vivo

GABAérgica inibição pré-sináptica é um poderoso mecanismo de inibição na espinal medula importante para o motor e a integração do sinal sensorial em redes da medula espinal. Subjacente despolarização aferente primário pode ser medido por registo dos potenciais de raiz dorsal (DRP). Aqui demonstramos um método in vivo de gravação de DRP em ratinhos.

Medindo Spinal pré-sináptica Inibição em Ratos por raiz dorsal Gravação Potencial<em&gt; In Vivo</em

Presynaptic inhibition is one of the most powerful inhibitory mechanisms in the spinal cord. The underlying physiological mechanism is a depolarization of ...

measuring-spinal-presynaptic-inhibition-mice-dorsal-root-potential

Research

JoVE Journal

Neuroscience

Measuring Spinal Presynaptic Inhibition in Mice By Dorsal Root Potential Recording In Vivo

13.9K visualizações.  Jena University Hospital, Jena, Germany.  GABAérgica inibição pré-sináptica é um poderoso mecanismo de inibição na espinal medula importante para o motor e a integração do sinal sensorial em redes da medula espinal. Subjacente despolarização aferente primário pode ser medido por registo dos potenciais de raiz dorsal (DRP). Aqui demonstramos um método in vivo de gravação de DRP em ratinhos. 

Vídeo: Measuring Spinal Presynaptic Inhibition in Mice By Dorsal Root Potential Recording In Vivo

Transfection of Mouse Retinal Ganglion Cells by in vivo Electroporation

The targeting and refinement of RGC projections to the midbrain is a popular and powerful model system for studying how precise patterns of neural connectivity form during development. In mice, retinofugal projections are arranged in a topographic manner and form eye-specific layers in the Lateral Geniculate Nucleus (dLGN) of the thalamus and the Superior Colliculus (SC). The development of these precise patterns of retinofugal projections has typically been studied by labeling populations of RGCs with fluorescent dyes and tracers, such as horseradish peroxidase1-4. However, these methods are too coarse to provide insight into developmental changes in individual RGC axonal arbor morphology that are the basis of retinotopic map formation. They also do not allow for the genetic manipulation of RGCs.
Recently, electroporation has become an effective method for providing precise spatial and temporal control for delivery of charged molecules into the retina5-11. Current retinal electroporation protocols do not allow for genetic manipulation and tracing of retinofugal projections of a single or small cluster of RGCs in postnatal mice. It has been argued that postnatal in vivo electroporation is not a viable method for transfecting RGCs since the labeling efficiency is extremely low and hence requires targeting at embryonic ages when RGC progenitors are undergoing differentiation and proliferation6. 
In this video we describe an in vivo electroporation protocol for targeted delivery of genes, shRNA, and fluorescent dextrans to murine RGCs postnatally. This technique provides a cost effective, fast and relatively easy platform for efficient screening of candidate genes involved in several aspects of neural development including axon retraction, branching, lamination, regeneration and synapse formation at various stages of circuit development. In summary we describe here a valuable tool which will provide further insights into the molecular mechanisms underlying sensory map development.

Transfection of Mouse Retinal Ganglion Cells by in vivo Electroporation

We demonstrate an in vivo electroporation protocol for transfecting single or small clusters of retinal ganglion cells (RGCs) and other retinal cell types in postnatal mice over a wide range of ages. The ability to label and genetically manipulate postnatal RGCs in vivo is a powerful tool for developmental studies.

Transfecção de células de camundongo por Ganglionares da Retina In vivo Eletroporação

The targeting and refinement of RGC projections to the midbrain is a popular and powerful model system for studying how precise patterns of neural ...

Neurociência

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 ...

Simultaneous ex vivo Functional Testing of Two Retinas by in vivo Electroretinogram System

An In vivo electroretinogram (ERG) signal is composed of several overlapping components originating from different retinal cell types, as well as noise from extra-retinal sources. Ex vivo ERG provides an efficient method to dissect the function of retinal cells directly from an intact isolated retina of animals or donor eyes. In addition, ex vivo ERG can be used to test the efficacy and safety of potential therapeutic agents on retina tissue from animals or humans. We show here how commercially available in vivo ERG systems can be used to conduct ex vivo ERG recordings from isolated mouse retinas. We combine the light stimulation, electronic and heating units of a standard in vivo system with custom-designed specimen holder, gravity-controlled perfusion system and electromagnetic noise shielding to record low-noise ex vivo ERG signals simultaneously from two retinas with the acquisition software included in commercial in vivo systems. Further, we demonstrate how to use this method in combination with pharmacological treatments that remove specific ERG components in order to dissect the function of certain retinal cell types.

Simultaneous ex vivo Functional Testing of Two Retinas by in vivo Electroretinogram System

Ex vivo ERG can be used to record electrical activity of retinal cells directly from isolated intact retinas of animals or humans. We demonstrate here how common in vivo ERG systems can be adapted for ex vivo ERG recordings in order to dissect the electrical activity of retinal cells.

Simultâneo<em&gt; Ex vivo</em&gt; Teste Funcional de Dois retinas por<em&gt; In vivo</em&gt; Sistema Eletrorretinograma

An In vivo electroretinogram (ERG) signal is composed of several overlapping components originating from different retinal cell types, as well as noise ...

Polygraphic Recording Procedure for Measuring Sleep in Mice

Recording of the epidural electroencephalogram (EEG) and electromyogram (EMG) in small animals, like mice and rats, has been pivotal to study the homeodynamics and circuitry of sleep-wake regulation. In many laboratories, a cable-based sleep recording system is used to monitor the EEG and EMG in freely behaving mice in combination with computer software for automatic scoring of the vigilance states on the basis of power spectrum analysis of EEG data. A description of this system is detailed herein. Steel screws are implanted over the frontal cortical area and the parietal area of 1 hemisphere for monitoring EEG signals. In addition, EMG activity is monitored by the bilateral placement of wires in both neck muscles. Non-rapid eye movement (Non-REM; NREM) sleep is characterized by large, slow brain waves with delta activity below 4 Hz in the EEG, whereas a shift from low-frequency delta activity to a rapid low-voltage EEG in the theta range between 6 and 10 Hz can be observed at the transition from NREM to REM sleep. By contrast, wakefulness is identified by low- to moderate-voltage brain waves in the EEG trace and significant EMG activity.

The recording of electroencephalogram (EEG) and electromyogram (EMG) in freely behaving mice is a critical step to correlate behavior and physiology with sleep and wakefulness. The experimental protocol described herein provides a cable-based system for acquiring EEG and EMG recordings in mice.

Procedimento de gravação Polygraphic para medição Sleep in Mice

Recording of the epidural electroencephalogram (EEG) and electromyogram (EMG) in small animals, like mice and rats, has been pivotal to study the ...

Hydraulic Extrusion of the Spinal Cord and Isolation of Dorsal Root Ganglia in Rodents

Traditionally, the spinal cord is isolated by laminectomy, i.e. by breaking open the spinal vertebrae one at a time. This is both time consuming and may result in damage to the spinal cord caused by the dissection process. Here, we show how the spinal cord can be extruded using hydraulic pressure. Handling time is significantly reduced to only a few minutes, likely decreasing protein damage. The low risk of damage to the spinal cord tissue improves subsequent immunohistochemical analysis. By performing hydraulic spinal cord extrusion instead of traditional laminectomy, the rodents can further be used for DRG isolation, thereby lowering the number of animals and allowing analysis across tissues from the same rodent. We demonstrate a consistent method to identify and isolate the DRGs according to their localization relative to the costae. It is, however, important to adjust this method to the particular animal used, as the number of spinal cord segments, both thoracic and lumbar, may vary according to animal type and strain. In addition, we illustrate further processing examples of the isolated tissues.

Here, we present a protocol for hydraulic extrusion of the spinal cord as well as identification and isolation of specific dorsal root ganglia (DRGs) in the same rodent. Compared to standard spinal cord isolation methods, this method is significantly faster and reduces the risk of tissue damage.

Extrusão hidráulico da medula espinhal e Isolamento de gânglios das raízes dorsais em roedores

Traditionally, the spinal cord is isolated by laminectomy, i.e. by breaking open the spinal vertebrae one at a time. This is both time consuming and may ...

Dorsal Root Ganglion Injection and Dorsal Root Crush Injury as a Model for Sensory Axon Regeneration

Achieving axon regeneration after nervous system injury is a challenging task. As different parts of the central nervous system (CNS) differ from each other anatomically, it is important to identify an appropriate model to use for the study of axon regeneration. By using a suitable model, we can formulate a specific treatment based on the severity of injury, the neuronal cell type of interest, and the desired spinal tract for assessing regeneration. Within the sensory pathway, DRG neurons are responsible for relaying sensory information from the periphery to the CNS. We present here a protocol that uses a DRG injection with a viral vector and a concurrent dorsal root crush injury in the lower cervical spinal cord of an adult rat as a model to study sensory axon regeneration. As demonstrated using a control virus, AAV5-GFP, we show the effectiveness of a direct DRG injection in transducing DRG neurons and tracing sensory axons into the spinal cord. We also show the effectiveness of the dorsal root crush injury in denervating the forepaw as an injury model for evaluating axon regeneration. Despite the requirement for specialized training to perform this invasive surgical procedure, the protocol is flexible, and potential users can modify many parts to accommodate their experimental requirements. Importantly, it can serve as a foundation for those in search of a suitable animal model for their studies. We believe that this article will help new users to learn the procedure in a very efficient and effective manner.

This protocol presents the use of a dorsal root ganglion (DRG) injection with a viral vector and a concurrent dorsal root crush injury in an adult rat as a model to study sensory axon regeneration. This model is suitable for investigating the use of gene therapy to promote sensory axon regeneration.

Dorsal Root Injection gânglio da raiz dorsal e lesão por esmagamento como um modelo para Sensorial Axon Regeneração

Achieving axon regeneration after nervous system injury is a challenging task. As different parts of the central nervous system (CNS) differ from each ...

Laminotomy for Lumbar Dorsal Root Ganglion Access and Injection in Swine

Dorsal root ganglia (DRG) are anatomically well defined structures that contain all primary sensory neurons below the head. This fact makes DRG attractive targets for injection of novel therapeutics aimed at treating chronic pain. In small animal models, laminectomy has been used to facilitate DRG injection because it involves surgical removal of the vertebral bone surrounding each DRG. We demonstrate a technique for intraganglionic injection of lumbar DRG in a large animal species, namely, swine. Laminotomy is performed to allow direct access to DRG using standard neurosurgical techniques, instruments, and materials. Compared with more extensive bone removal via laminectomy, we implement laminotomy to conserve spinal anatomy while achieving sufficient DRG access. Intraoperative progress of DRG injection is monitored using a non-toxic dye. Following euthanasia on post-operative day 21, the success of injection is determined by histology for intraganglionic distribution of 4&#39;,6-diamidino-2-phenylindole (DAPI). We inject a biologically inactive solution to demonstrate the protocol. This method could be applied in future preclinical studies to target therapeutic solutions to DRG. Our methodology should facilitate testing the translatability of intraganglionic small animal paradigms in a large animal species. Additionally, this protocol may serve as a key resource for those planning preclinical studies of DRG injection in swine.

We describe a method for laminotomy in swine that provides access to lumbar dorsal root ganglia (DRG) for intraganglionic injection. Injection progress is monitored intraoperatively and histologically confirmed up to 21 days after surgery. This protocol could be used for future preclinical studies involving DRG injection.

Laminotomy para acesso de gânglio lombar Dorsal raiz e injeção em suínos

Dorsal root ganglia (DRG) are anatomically well defined structures that contain all primary sensory neurons below the head. This fact makes DRG attractive ...

Investigating Mammalian Axon Regeneration: In Vivo Electroporation of Adult Mouse Dorsal Root Ganglion

Electroporation is an essential non-viral gene transfection approach to introduce DNA plasmids or small RNA molecules into cells. A sensory neuron in the dorsal root ganglion (DRGs) extends a single axon with two branches. One branch goes to the peripheral nerve (peripheral branch), and the other branch enters the spinal cord through the dorsal root (central branch). After the neural injury, the peripheral branch regenerates robustly whereas the central branch does not regenerate. Due to the high regenerative capacity, sensory axon regeneration has been widely used as a model system to study mammalian axon regeneration in both the peripheral nervous system (PNS) and the central nervous system (CNS). Here, we describe a previously established approach protocol to manipulate gene expression in mature sensory neurons in vivo via electroporation. Based on transfection with plasmids or small RNA oligos (siRNAs or microRNAs), the approach allows for both loss- and gain-of-function experiments to study the roles of genes-of-interests or microRNAs in regulation of axon regeneration in vivo. In addition, the manipulation of gene expression in vivo can be controlled both spatially and temporally within a relatively short time course. This model system provides a unique tool to investigate the molecular mechanisms by which mammalian axon regeneration is regulated in vivo.

Investigating Mammalian Axon Regeneration: In Vivo Electroporation of Adult Mouse Dorsal Root Ganglion

Electroporation is an effective approach to deliver genes of interests into cells. By applying this approach in vivo on the neurons of adult mouse dorsal root ganglion (DRG), we describe a model to study axon regeneration in vivo.

Investigação regeneração do axônio mamíferos: In Vivo Electroporation do gânglio de raiz Dorsal do rato adulto

Electroporation is an essential non-viral gene transfection approach to introduce DNA plasmids or small RNA molecules into cells. A sensory neuron in the ...

Use of In Vivo Single-fiber Recording and Intact Dorsal Root Ganglion with Attached Sciatic Nerve to Examine the Mechanism of Conduction Failure

Single-fiber recording has been a classical and effective electrophysiological technique over the last few decades because of its specific application for nerve fibers in the central and peripheral nervous systems. This method is particularly applicable to dorsal root ganglia (DRG), which are primary sensory neurons that exhibit a pseudo-unipolar structure of nervous processes. The patterns and features of the action potentials passed along axons are recordable in these neurons. The present study uses in vivo single-fiber recordings to observe the conduction failure of sciatic nerves in complete Freund&#8217;s adjuvant (CFA)-treated rats. As the underlying mechanism cannot be studied using in vivo single-fiber recordings, patch-clamp-recordings of DRG neurons are performed on preparations of intact DRG with the attached sciatic nerve. These recordings reveal a positive correlation between conduction failure and the rising slope of the after-hyperpolarization potential (AHP) of DRG neurons in CFA-treated animals. The protocol for in vivo single fiber-recordings allows the classification of nerve fibers via the measurement of conduction velocity and monitoring of abnormal conditions in nerve fibers in certain diseases. Intact DRG with attached peripheral nerve allows observation of the activity of DRG neurons in most physiological conditions. Conclusively, single-fiber recording combined with electrophysiological recording of intact DRGs is an effective method to examine the role of conduction failure during the analgesic process.

Single-fiber recording is an effective electrophysiological technique that is applicable to the central and peripheral nervous systems. Along with the preparation of intact DRG with the attached sciatic nerve, the mechanism of conduction failure is examined. Both protocols improve the understanding of the peripheral nervous system&#39;s relationship with pain.

Uso da gravação in vivo da único-fibra e do gânglio dorsal intacto da raiz com nervo sciatic Unido para examinar o mecanismo da falha da condução

Single-fiber recording has been a classical and effective electrophysiological technique over the last few decades because of its specific application for ...

Rapid Isolation of Dorsal Root Ganglion Macrophages

There are growing interests to study the molecular and cellular interactions among immune cells and sensory neurons in the dorsal root ganglia after peripheral nerve injury. Peripheral monocytic cells, including macrophages, are known to respond to a tissue injury through phagocytosis, antigen presentation, and cytokine release. Emerging evidence has implicated the contribution of dorsal root ganglia macrophages to neuropathic pain development and axonal repair in the context of nerve injury. Rapidly phenotyping (or &#8220;rapid isolation of&#8221;) the response of dorsal root ganglia macrophages in the context of nerve injury is desired to identify the unknown neuroimmune factors. Here we demonstrate how our lab rapidly and effectively isolates macrophages from the dorsal root ganglia using an enzyme-free mechanical dissociation protocol. The samples are kept on ice throughout to limit cellular stress. This protocol is far less time consuming compared to the standard enzymatic protocol and has been routinely used for our Fluorescence-activated Cell Sorting analysis.

Here we present a mechanical dissociation protocol to rapidly isolate macrophages from the dorsal root ganglion for phenotyping and functional analysis.

Isolação rápida de macrófagos dorsal do gânglio da raiz

There are growing interests to study the molecular and cellular interactions among immune cells and sensory neurons in the dorsal root ganglia after ...