Setup Grampo patch: Óptica: A ótica é muito importante encontrar um celular bom, e para estabelecer a posição dele. Tentar obter uma imagem clara das células: bordas afiadas, soft-olhando celular. Digitalizar todo o campo para procurar boas MNTB células principais com cálice em anexo. Prato girar para procurar cálices de diferentes ângulos. Na primeira, ele está OK para a prática do balão em forma de terminal. Escolha de células na superfície da fatia, ou na camada de células 2 ª. Alvo da rd 03/01 primeiro celular com pipeta Identificar cálices: Procure uma membrana dupla (ver figura 1) e gire o prato fatia para vê-lo de ângulos diferentes para ajudar a confirmar que é um cálice. <img src="/files/ftp_upload/old/244_2008_8_22_2/244_Figure-01.png" alt="Figura 1" width="298" height="159" /> Figura 1 Profundidade da Calyx: Calyx deve estar na superfície ou o mais próximo à superfície possível. De superfície disponível para aplicação de patches: Use o foco fino botão no microscópio para determinar como &quot;wide / deep&quot; o cálice é. Por exemplo, ~ 10% de uma volta completa sobre o foco fino lhe dará mais de área de superfície suficiente para corrigir em. Vedação em uma célula pré-sináptica: Para chegar ao celular ligado, procure uma deformação &quot;pequeno&quot; na superfície da célula, devido à pos de pressão (~ 0.15psi) na pipeta, use manipulador para executar pipeta cima, para baixo e em frente, e até mesmo em a superfície do terminal presyn para obter uma deformação bom, em seguida, solte a pressão e sucção, se e quando necessário. PULSE, dados do programa de aquisição: Necessidade de aumentar o tamanho do buffer antes da primeira utilização e, sempre que exigido pela capacidade de amostragem. Necessidade de carregar macros modificado a cada vez. Junção Potencial líquido: Solução de Gravação Presyn é-11mV (11mV negativo). Presyn: Cslow = ~ 15 pF Rs comp para presyn: 10 ms, 65% (mais possível a compensação pode w / out oscilações) Antes de capacitância de gravação: relaxamento Corrente de teste (10 mV, 10 ms salto) para ver se o relaxamento é monoexponencial, ou seja, se presyn prazo pode ser modelado por um único compartimento. Filtros: Situado a 30 kHz e 10 kHz (Bessel filtro 1 e 2, respectivamente) durante a medição de relaxamento, para ter certeza de um componente rápido não é perdido para fora. Durante as gravações mini, Xinsheng usado 10 kHz e 5 kHz. LBV me pediu para usar apenas 1 conjunto de filtro de 30 kHz para ter certeza de que podemos medir tempo de subida de mini. Nomear arquivos: 7 dígitos 000mmxx, onde mm é o mês (ou mês e ano) e xx é o número de células. Linhas de limpeza Solução: Linhas limpas no final do experimento com 20 ml de 0,1 M HCl seguido por 200 ml ddH2O. Soluções externas são reciclados, a velocidade da bomba é 20-30 rpm. (Solução de retornar da câmara de banho flui de volta para o cilindro graduado). Criar três linhas de saída para garantir sucção suficiente. Adição da solução de gravação pré-sináptica: ~ 310 milli Osmolar Solução Presyn precisa ser ~ 310 mOsm para impedir R acesso aumentam durante a experiência. Presyn solução pipeta é diferente de postsyn pipeta solução (Presyn tem ATP e GTP por ex.). TTX-TEA Solução (para isolar Ca correntes): <ul><li> Tentar aplicar após a selagem, ou mesmo o patch, para a célula, como TEA em blocos solução K-canais e despolariza a célula. Isso não é bom para a célula. Pela mesma razão, pode não ser possível a reutilização da fatia após TTX é aplicada. </li><li> Compare a resposta primeiro e último da célula, ou uma fatia para verificar se há algum efeito de despolarização prolongada. </li><li> TTX é utilizada até 1 mM em vez de 0,5 mM de modo que o efeito é mais rápido. Necessidade de esperar menos tempo depois de mudar soluções. </li></ul> Fatias de corte Vibratome configurações: <ul><li> 70Hz vibrações laterais </li><li> Amplitude: 1,0 milímetros </li><li> A velocidade de avanço 0,01-0,02 mm / seg, enquanto corta fatias de cálice, 0,1 espessura de outra forma: 180 M (~ 150M em animais mais velhos) </li></ul> Fatias de incubar a 37 º C por 1 hora (inclui o tempo de corte), ou seja, deixar em banho de 15-20 minutos após o corte. Pipetas: Presyn: 3,5-4,5 mohms num primeiro momento, 3,0-3,5 mohms quando se sentir mais confiante Uso manual extrator para definir as configurações. Use recurso de atraso porque o vidro é grosso (atrasos de 200 ou um trabalho) Vidro tipo: borosilicato, padrão parede, nenhum filamento Diâmetro externo: 2,0 mm Diâmetro interno 1,16 milímetros Comprimento: 7.5 cm

methods for patch clamp capacitance recordings from the calyx

Demonstramos as técnicas básicas para a gravação pré-sináptica patch-clamp no cálice de Held, um terminal de nervo do sistema nervoso central de mamíferos. Gravações elétrica do terminal pré-sináptico permitem a medição de potenciais de ação, as correntes dos canais de cálcio, fusão das vesículas (exocitose) e absorção da membrana subseqüentes (endocitose). A fusão das vesículas contendo neurotransmissor faz com que a membrana da vesícula para ser adicionado à membrana celular do cálice. Este aumento na quantidade de membrana celular é medida como um aumento na capacitância. A redução subsequente na capacitância indica endocitose, o processo de captação de membrana ou remoção da membrana cálice. Endocitose, é necessário manter a estrutura do cálice e também é necessário para formar vesículas que será preenchido com neurotransmissor para eventos exocitose futuro. Gravações de capacitância no cálice de Held tornaram possível a direta e rapidamente medida liberação vesicular e endocitose subseqüentes em um terminal de mamíferos CNS nervosas. Além disso, a atividade correspondente pós-sinápticos podem ser medidos em simultâneo usando gravações emparelhados. Assim, um quadro completo da atividade pré-sináptica e pós-sináptica elétrica em uma sinapse do sistema nervoso central é viável o uso desta preparação. Aqui, os métodos para a preparação fatia, características morfológicas para a identificação de cálices de Held, patches técnicas básicas de fixação, e exemplos de gravações para medir a capacitância exocitose e endocitose são apresentados.

Watch this Scientific Journal Video about Methods for Patch Clamp Capacitance Recordings from the Calyx at JoVE.com

Methods for Patch Clamp Capacitance Recordings from the Calyx

Métodos para Recordings patch-clamp Capacitância da Calyx

We demonstrate the basic techniques for presynaptic patch clamp recording at the calyx of Held, a mammalian central nervous system nerve terminal. ...

methods-for-patch-clamp-capacitance-recordings-from-the-calyx

Nanyang Technological University

Research

JoVE Journal

Biology

12.6K visualizações.  National Institute of Health. 

Vídeo: Methods for Patch Clamp Capacitance Recordings from the Calyx

Patch Clamp Recording of Ion Channels Expressed in  Xenopus Oocytes

Since its development by Sakmann and Neher 1, 2, the patch clamp has become established as an extremely useful technique for electrophysiological measurement of single or multiple ion channels in cells. This technique can be applied to ion channels in both their native environment and expressed in heterologous cells, such as oocytes harvested from the African clawed frog, Xenopus laevis. Here, we describe the well-established technique of patch clamp recording from Xenopus oocytes. This technique is used to measure the properties of expressed ion channels either in populations (macropatch) or individually (single-channel recording). We focus on techniques to maximize the quality of oocyte preparation and seal generation. With all factors optimized, this technique gives a probability of successful seal generation over 90 percent. The process may be optimized differently by every researcher based on the factors he or she finds most important, and we present the approach that have lead to the greatest success in our hands.

This is intended as an introduction to patch clamp recording from Xenopus laevis oocytes. It covers vitelline membrane removal, formation of a gigaohm seal (gigaseal), and the optional conversion of the patch to the outside-out topology.

Gravação de patch-clamp de canais iônicos Expresso em Oócitos Xenopus

Since its development by Sakmann and Neher 1, 2, the patch clamp has become established as an extremely useful technique for electrophysiological ...

Biologia

Pressure-polishing Pipettes for Improved Patch-clamp Recording

Pressure-polishing is a method for shaping glass pipettes for patch-clamp recording. We first developed this method for fabricating pipettes suitable for recording from small (&lt;3 m) neuronal cell bodies. The basic principal is similar to glass-blowing and combines air pressure and heat to modify the shape of patch pipettes prepared by a conventional micropipette puller. It can be applied to so-called soft (soda lime) and hard (borosilicate) glasses. Generally speaking, pressure polishing can reduce pipette resistance by 25% without decreasing the diameter of the tip opening (Goodman and Lockery, 2000). It can be applied to virtually any type of glass and requires only the addition of a high-pressure valve and fitting to a microforge. This technique is essential for recording from ultrasmall cells (&lt;5 m) and can also improve single-channel recording by minimizing pipette resistance. The blunt shape is also useful for perforated-patch clamp recording since this tip shape results in a larger membrane bleb available for perforation.

This is a guide to modifying the shape of glass micropipettes. Specifically, by using heat and air pressure the taper is widened without increasing the tip opening, leading to lower pipette resistance. This is critical to obtain low noise recordings of small cells but is useful in many applications.

Pressão polimento Pipetas para Gravação de patch-clamp melhorada

Pressure-polishing is a method for shaping glass pipettes for patch-clamp recording.  We first developed this method for fabricating pipettes suitable for ...

Electrophysiological Methods for Recording Synaptic Potentials from the NMJ of Drosophila Larvae

In this video, we describe the electrophysiological methods for recording synaptic transmission at the neuromuscular junction (NMJ) of Drosophila larva. The larval neuromuscular system is a model synapse for the study of synaptic physiology and neurotransmission, and is a valuable research tool that has defined genetics and is accessible to experimental manipulation. Larvae can be dissected to expose the body wall musculature, central nervous system, and peripheral nerves. The muscles of Drosophila and their innervation pattern are well characterized and muscles are easy to access for intracellular recording. Individual muscles can be identified by their location and orientation within the 8 abdominal segments, each with 30 muscles arranged in a pattern that is repeated in segments A2 - A7. Dissected drosophila larvae are thin and individual muscles and bundles of motor neuron axons can be visualized by transillumination1. Transgenic constructs can be used to label target cells for visual identification or for manipulating gene products in specific tissues. In larvae, excitatory junction potentials (EJP&#8217;s) are generated in response to vesicular release of glutamate from the motoneurons at the synapse. In dissected larvae, the EJP can be recorded in the muscle with an intracellular electrode. Action potentials can be artificially evoked in motor neurons that have been cut posterior to the ventral ganglion, drawn into a glass pipette by gentle suction and stimulated with an electrode. These motor neurons have distinct firing thresholds when stimulated, and when they fire simultaneously, they generate a response in the muscle. Signals transmitted across the NMJ synapse can be recorded in the muscles that the motor neurons innervate. The EJP&#8217;s and minature excitatory junction potentials (mEJP&#8217;s) are seen as changes in membrane potential. Electrophysiological responses are recorded at room temperature in modified minimal hemolymph-like solution2 (HL3) that contains 5 mM Mg2+ and 1.5 mM Ca2+. Changes in the amplitude of evoked EJP&#8217;s can indicate differences in synaptic function and structure. Digitized recordings are analyzed for EJP amplitude, mEJP frequency and amplitude, and quantal content.

Here we describe electrophysiological methods for measuring synaptic transmission at the neuromuscular junction of Drosophila larva. Evoked release is initiated artificially by stimulating the motor neuron axons, and transmission through the NMJ can be measured by the postsynaptic response evoked in the muscle.

Métodos eletrofisiológicos de gravação Potenciais Synaptic do MNJ de larvas de Drosophila

In this video, we describe the electrophysiological methods for recording synaptic transmission at the neuromuscular junction (NMJ) of Drosophila larva. ...

Methods for the Study of the Zebrafish Maxillary Barbel

Barbels are skin sensory appendages found in fishes, reptiles and amphibians. The zebrafish, Danio rerio, develops two pairs of barbels- a short nasal pair and a longer maxillary pair. Barbel tissue contains cells of ectodermal, mesodermal and neural crest origin, including skin cells, glands, taste buds, melanocytes, circulatory vessels and sensory nerves. Unlike most adult tissue, the maxillary barbel is optically clear, allowing us to visualize the development and maintenance of these tissue types throughout the life cycle. 
This video shows early development of the maxillary barbel (beginning approximately one month post-fertilization) and demonstrates a surgical protocol to induce regeneration in the adult appendage (&gt;3 months post-fertilization). Briefly, the left maxillary barbel of an anesthetized fish is elevated with sterile forceps just distal to the caudal edge of the maxilla. A fine, sterile spring scissors is positioned against the forceps to cut the barbel shaft at this level, establishing an anatomical landmark for the amputation plane. Regenerative growth can be measured with respect to this plane, and in comparison to the contralateral barbel. Barbel tissue regenerates rapidly, reaching maximal regrowth within 2 weeks of injury.
Techniques for analyzing the regenerated barbel include dissecting and embedding matched pairs of barbels (regenerate and control) in the wells of a standard DNA electrophoresis gel. Embedded specimens are conveniently photographed under a stereomicroscope for gross morphology and morphometry, and can be stored for weeks prior to downstream applications such as paraffin histology, cryosectioning, and/or whole mount immunohistochemistry. These methods establish the maxillary barbel as a novel in vivo tissue system for studying the regenerative capacity of multiple cell types within the genetic context of zebrafish.

The zebrafish maxillary barbel is an integumentary sense organ containing ectodermal, mesodermal and neural crest derivatives. Importantly, the adult barbel can regenerate after proximal amputation. This video introduces maxillary barbel development and demonstrates a surgical protocol to induce regeneration, followed by collection, embedding and downstream imaging of barbel specimens.

Métodos para o Estudo do maxilar Zebrafish Barbel

Barbels are skin sensory appendages found in fishes, reptiles and amphibians.  The zebrafish, Danio rerio, develops two pairs of barbels- a short nasal ...

Patch Clamp and Perfusion Techniques for Studying Ion Channels Expressed in Xenopus oocytes

The protocol presented here is designed to study the activation of the large conductance, voltage- and Ca2+-activated K+ (BK) channels. The protocol may also be used to study the structure-function relationship for other ion channels and neurotransmitter receptors1. BK channels are widely expressed in different tissues and have been implicated in many physiological functions, including regulation of smooth muscle contraction, frequency tuning of inner hair cells and regulation of neurotransmitter release2-6. BK channels are activated by membrane depolarization and by intracellular Ca2+ and Mg2+ 6-9. Therefore, the protocol is designed to control both the membrane voltage and the intracellular solution. In this protocol, messenger RNA of BK channels is injected into Xenopus laevis oocytes (stage V-VI) followed by 2-5 days of incubation at 18&deg;C10-13. Membrane patches that contain single or multiple BK channels are excised with the inside-out configuration using patch clamp techniques10-13. The intracellular side of the patch is perfused with desired solutions during recording so that the channel activation under different conditions can be examined. To summarize, the mRNA of BK channels is injected into Xenopus laevis oocytes to express channel proteins on the oocyte membrane; patch clamp techniques are used to record currents flowing through the channels under controlled voltage and intracellular solutions.

Patch Clamp and Perfusion Techniques for Studying Ion Channels Expressed in Xenopus oocytes

Ionic current of BK channels is recorded using patch clamp techniques. BK channels are expressed in Xenopus oocytes by injecting messenger RNA. The intracellular solution during patch clamp recordings is controlled by a perfusion system.

Grampo patch e Técnicas de Perfusão para estudar canais iônicos Expresso em Xenopus Oócitos

The protocol presented here is designed to study the activation of the large conductance, voltage- and Ca2+-activated K+ (BK) channels. The protocol may ...

Exploring Arterial Smooth Muscle Kv7 Potassium Channel Function using Patch Clamp Electrophysiology and Pressure Myography

Contraction or relaxation of smooth muscle cells within the walls of resistance arteries determines the artery diameter and thereby controls flow of blood through the vessel and contributes to systemic blood pressure. The contraction process is regulated primarily by cytosolic calcium concentration ([Ca2+]cyt), which is in turn controlled by a variety of ion transporters and channels. Ion channels are common intermediates in signal transduction pathways activated by vasoactive hormones to effect vasoconstriction or vasodilation. And ion channels are often targeted by therapeutic agents either intentionally (e.g. calcium channel blockers used to induce vasodilation and lower blood pressure) or unintentionally (e.g. to induce unwanted cardiovascular side effects).
Kv7 (KCNQ) voltage-activated potassium channels have recently been implicated as important physiological and therapeutic targets for regulation of smooth muscle contraction. To elucidate the specific roles of Kv7 channels in both physiological signal transduction and in the actions of therapeutic agents, we need to study how their activity is modulated at the cellular level as well as evaluate their contribution in the context of the intact artery.
The rat mesenteric arteries provide a useful model system. The arteries can be easily dissected, cleaned of connective tissue, and used to prepare isolated arterial myocytes for patch clamp electrophysiology, or cannulated and pressurized for measurements of vasoconstrictor/vasodilator responses under relatively physiological conditions. Here we describe the methods used for both types of measurements and provide some examples of how the experimental design can be integrated to provide a clearer understanding of the roles of these ion channels in the regulation of vascular tone.

Measurements of Kv7 (KCNQ) potassium channel activity in isolated arterial myocytes (using patch clamp electrophysiological techniques) in parallel with measurements of constrictor/dilator responses (using pressure myography) can reveal important information about the roles of Kv7 channels in vascular smooth muscle physiology and pharmacology.

Explorando Arterial Músculo Liso KV7 função dos canais de potássio utilizando electrofisiologia patch clamp e Miografia Pressão

Contraction  or relaxation of smooth muscle cells within the walls of resistance arteries  determines the artery diameter and thereby controls flow of ...

Giant Liposome Preparation for Imaging and Patch-Clamp Electrophysiology

The reconstitution of ion channels into chemically defined lipid membranes for electrophysiological recording has been a powerful technique to identify and explore the function of these important proteins. However, classical preparations, such as planar bilayers, limit the manipulations and experiments that can be performed on the reconstituted channel and its membrane environment. The more cell-like structure of giant liposomes permits traditional patch-clamp experiments without sacrificing control of the lipid environment.
Electroformation is an efficient mean to produce giant liposomes &gt;10 &mu;m in diameter which relies on the application of alternating voltage to a thin, ordered lipid film deposited on an electrode surface. However, since the classical protocol calls for the lipids to be deposited from organic solvents, it is not compatible with less robust membrane proteins like ion channels and must be modified. Recently, protocols have been developed to electroform giant liposomes from partially dehydrated small liposomes, which we have adapted to protein-containing liposomes in our laboratory.
We present here the background, equipment, techniques, and pitfalls of electroformation of giant liposomes from small liposome dispersions. We begin with the classic protocol, which should be mastered first before attempting the more challenging protocols that follow. We demonstrate the process of controlled partial dehydration of small liposomes using vapor equilibrium with saturated salt solutions. Finally, we demonstrate the process of electroformation itself. We will describe simple, inexpensive equipment that can be made in-house to produce high-quality liposomes, and describe visual inspection of the preparation at each stage to ensure the best results.

Reconstituting functional membrane proteins into giant liposomes of defined composition is a powerful approach when combined with patch-clamp electrophysiology. However, conventional giant liposome production may be incompatible with protein stability. We describe protocols for producing giant liposomes from pure lipids or small liposomes containing ion channels.

Preparação de lipossomas gigantes por Imagem e patch-clamp Eletrofisiologia

The reconstitution of ion channels into chemically defined lipid membranes for electrophysiological recording has been a powerful technique to identify ...

One-channel Cell-attached Patch-clamp Recording

Ion channel proteins are universal devices for fast communication across biological membranes. The temporal signature of the ionic flux they generate depends on properties intrinsic to each channel protein as well as the mechanism by which it is generated and controlled and represents an important area of current research. Information about the operational dynamics of ion channel proteins can be obtained by observing long stretches of current produced by a single molecule. Described here is a protocol for obtaining one-channel cell-attached patch-clamp current recordings for a ligand gated ion channel, the NMDA receptor, expressed heterologously in HEK293 cells or natively in cortical neurons. Also provided are instructions on how to adapt the method to other ion channels of interest by presenting the example of the mechano-sensitive channel PIEZO1. This method can provide data regarding the channel&#8217;s conductance properties and the temporal sequence of open-closed conformations that make up the channel&#8217;s activation mechanism, thus helping to understand their functions in health and disease.

Described here is a procedure for obtaining long stretches of current recording from one ion channel with the cell-attached patch-clamp technique. This method allows for observing, in real time, the pattern of open-close channel conformations that underlie the biological signal. These data inform about channel properties in undisturbed biological membranes.

Um canal de gravação de patch-clamp anexado-Cell

Ion channel proteins are universal devices for fast communication across biological membranes. The temporal signature of the ionic flux they generate ...

Reconstitution of a Transmembrane Protein, the Voltage-gated Ion Channel, KvAP, into Giant Unilamellar Vesicles for Microscopy and Patch Clamp Studies

Giant Unilamellar Vesicles (GUVs) are a popular biomimetic system for studying membrane associated phenomena. However, commonly used protocols to grow GUVs must be modified in order to form GUVs containing functional transmembrane proteins. This article describes two dehydration-rehydration methods &#8212; electroformation and gel-assisted swelling &#8212; to form GUVs containing the voltage-gated potassium channel, KvAP. In both methods, a solution of protein-containing small unilamellar vesicles is partially dehydrated to form a stack of membranes, which is then allowed to swell in a rehydration buffer. For the electroformation method, the film is deposited on platinum electrodes so that an AC field can be applied during film rehydration. In contrast, the gel-assisted swelling method uses an agarose gel substrate to enhance film rehydration. Both methods can produce GUVs in low (e.g., 5 mM) and physiological (e.g., 100 mM) salt concentrations. The resulting GUVs are characterized via fluorescence microscopy, and the function of reconstituted channels measured using the inside-out patch-clamp configuration. While swelling in the presence of an alternating electric field (electroformation) gives a high yield of defect-free GUVs, the gel-assisted swelling method produces a more homogeneous protein distribution and requires no special equipment.

The reconstitution of the transmembrane protein, KvAP, into giant unilamellar vesicles (GUVs) is demonstrated for two dehydration-rehydration methods &#8212; electroformation, and gel-assisted swelling. In both methods, small unilamellar vesicles containing the protein are fused together to form GUVs that can then be studied by fluorescence microscopy and patch-clamp electrophysiology.

Reconstituição de uma proteína transmembrana, a voltagem-Ion Channel, KvAP, em Gigante Unilamelares Vesicles para microscopia e de Patch Estudos Grampo

Giant Unilamellar Vesicles (GUVs) are a popular biomimetic system for studying membrane associated phenomena. However, commonly used protocols to grow ...

Implementing Patch Clamp and Live Fluorescence Microscopy to Monitor Functional Properties of Freshly Isolated PKD Epithelium

Cyst initiation and expansion during polycystic kidney disease is a complex process characterized by abnormalities in tubular cell proliferation, luminal fluid accumulation and extracellular matrix formation. Activity of ion channels and intracellular calcium signaling are key physiologic parameters which determine functions of tubular epithelium. We developed a method suitable for real-time observation of ion channels activity with patch-clamp technique and registration of intracellular Ca2+ level in epithelial monolayers freshly isolated from renal cysts. PCK rats, a genetic model of autosomal recessive polycystic kidney disease (ARPKD), were used here for ex vivo analysis of ion channels and calcium flux. Described here is a detailed step-by-step procedure designed to isolate cystic monolayers and non-dilated tubules from PCK or normal Sprague Dawley (SD) rats, and monitor single channel activity and intracellular Ca2+ dynamics. This method does not require enzymatic processing and allows analysis in a native setting of freshly isolated epithelial monolayer. Moreover, this technique is very sensitive to intracellular calcium changes and generates high resolution images for precise measurements. Finally, isolated cystic epithelium can be further used for staining with antibodies or dyes, preparation of primary cultures and purification for various biochemical assays.

Ion channels expressed in renal tubular epithelium play a significant role in the pathology of polycystic kidney disease. Here we describe experimental protocols used to perform patch-clamp analysis and intracellular calcium level measurements in cystic epithelium freshly isolated from rodent kidneys.

Implementando Grampo patch e ao vivo microscopia de fluorescência para monitorar propriedades funcionais de recentemente isolados PKD Epithelium

Cyst initiation and expansion during polycystic kidney disease is a complex process characterized by abnormalities in tubular cell proliferation, luminal ...