作者想感谢格伦·斯洛克姆（威斯康星医学院）和科琳A.拉文（尼康仪器公司）与显微镜实验优秀的技术援助。这项研究是支持由美国国立卫生研究院授予R01 HL108880（以AS），R01 DK095029（以OPO）和K99 HL116603（以TSP），全国肾脏基金会IG1724（以TSP），美国心脏协会13GRNT16220002（以OPO）和本·J.里普斯研究奖学金由美国肾脏病学会（至DVI）。

下面描述的实验程序，在威斯康星州和德克萨斯大学健康科学中心休斯敦大学医学院获得批准的机构动物护理和使用委员会，并分别按照卫生指南实验动物的护理和使用国家研究院​​。 图1显示的组织分离和处理过程的主要步骤。简要地说，从PCK或SD大鼠的肾脏用于收集无论是从健康非拨小管或囊肿导管上皮单层的手动隔离。在这里，我们从4-16周龄PCK大鼠10,13研究肾脏。 1.肾囊肿和连接小管（CNT）/隔离集合管（CD）段<ol><li>麻醉实验动物异氟醚（5％的诱导，1.5〜2.5％的维护）/医用级O 2或其他经批准的方法。动物必须不断监控，以确保有足够的文件韦尔麻醉。稳定的呼吸频率和脚趾捏的反应是用来确定适当的麻醉。 </li><li>执行剖腹并通过腹主动脉17冲洗用磷酸缓冲盐水（PBS）的肾脏。 <ol><li>准备一个聚乙烯管导管（PE50），并把它连接到注射泵填充有PBS。切开皮肤和腹壁沿白线，然后使整个腹部横向腹部切口，从一边到另一边倒腾腹部器官用棉签以访问降主动脉与肠系膜分支和腹腔动脉。在进一步的过程滋润五脏六腑用温生理盐水，以防止其干燥。 </li><li>将一个连字（＃1）周围的肠系膜和腹腔动脉，另一结扎（＃2）周围的隔膜下主动脉（不打领带）。轻轻分开一个。腹钝性解剖结缔组织周围薄镊子把两个连写〜3左肾动脉下方毫米（＃3）和上述髂动脉分叉（＃4）。 </li><li>领带结扎＃4和附加周围左肾动脉结扎和＃3之间的主动脉的容器夹具。使钳和结扎＃4导尿主动脉之间的切口，用绷带＃3牢固地固定导管。 </li><li>释放夹紧并确保该脉是在导管可见以确保正确安装。开始灌流以6ml / min的速率，领带连字＃1和＃2，和切断左肾静脉。继续冲洗1-2分钟，直到脏器完全变白。 </li><li>切肾血管，尿道口及其周围结缔组织和脂肪组织用剪刀来收集肾脏。然后作一个简短的撕裂肾囊和剥离肾脏解封他们。将肾脏入冰 - 冷PBS。安乐死是通过开胸手术证实。 </li></ol></li><li>制备涂覆有聚-L-赖氨酸的5×5毫米玻璃盖片。切盖GLA分类用金刚石铅笔和地点大约20微升的0.01％无菌过滤聚-L-赖氨酸溶液到每玻璃芯片。准备生理盐水和两对制表师镊子解剖。 </li><li>切断与沿冠状面刀片肾脏进入1-2毫米厚度的〜切片。放置在立体显微镜下的片段之一。组织的分离应在冰冷盐水来完成。 </li><li>定位在立体显微镜下为圆形状的空腔（图2A）囊肿;他们的墙壁通常含有增生的血管突出的网络。使用细尖镊子解剖囊肿尽可能地薄，得到的单层面积的内部上皮细胞层。它附加到覆盖有聚L-赖氨酸的玻璃片。粘聚-L-赖氨酸表面允许研究者牢牢定位在玻璃内部囊肿层。暴露与顶侧上的囊肿，以提供接入。移液器（图2B）。 </li><li>使用PCK或SD大鼠的孩子内伊中央片含有乳头的非扩张的CNT / CCDsegments 18-21隔离。 注：乳头状组织比皮质和保持乳头管带用钳子和沿径向轴撕裂片可切割为薄部门更持久。个别小管是可见的，并可以拉出到被放置在盖玻璃芯片。 </li><li>识别将CNT / CCD段由分岔，比近端小管和大显着可见的细胞（图2C）更高的透明度。放置附有小管的玻璃盖片上配备有适合驱动微量显微在显微镜下。使用锋利的微量分割开管和连接它们的边缘到玻璃使顶端表面可访问（图2D）。 </li></ol> 2.单通道膜片钳电<ol><li>填充膜片钳室浴溶液和传送护罩玻璃芯片与离体组织到腔室。确保膜片钳微量具有7-10兆欧电阻为可靠的细胞（细胞连接的）测量。 </li><li>对于细胞贴附测量，将放大器的增益比20倍，并通过一个八极贝塞尔滤波器低通的电流，在300赫兹。对于ENaC的频道监测，使用一个浴溶液，以mM：150的NaCl，1的CaCl 2，2的MgCl 2，10 HEPES（pH 7.4）中;吸移管：140的LiCl，2的MgCl 2和10的HEPES（pH 7.4）中。 </li><li>进行常规的膜片钳实验中一个细胞贴附模式10。选择在上皮单层的细胞并接近吸管顶膜。形成通过施加轻柔抽吸吸管和细胞膜之间的高电阻密封。一旦高耐千兆欧姆密封形成，在保持电位的间隙 - 自由协议应启动针对感兴趣的信道的监视活动。 </li><li>从千兆存储的无间隙的单通道电流数据欧姆密封件进行后续分析。分析使用一般用膜片钳设置18提供的软件包的渠道活动。计算信道活性NPO其中N是指在贴片和P 2 O的活性通道的数量是信道的平均开放概率。 注：使用孤立囊肿或小管在膜片钳实验中不超过30分钟。 </li></ol>细胞内钙离子浓度的上皮细胞3成比例落射荧光测量<ol><li>使用5mM的的Fura-2AM溶解在DMSO中。等分试样原液成单独的500μl的锥形管中（约10微升）。从光线并存储在冰箱在-20℃下长达半年的保护。 </li><li>在PSS孵育孤立囊肿和分裂开管30-40分钟（毫米：145氯化钠，氯化钾4.5，2 氯化镁 ，氯化钙2 2和 10 HEPES pH值为7.35），含5微 ​​米的Fura-2 AM染料和0.05％聚醚酸有助于驱散乙酰氧基甲基酯。为此，含有装载鸡尾酒地方的组织在3.5厘米培养皿，避光孵育一个缓慢摇动器上在室温下进行。 </li><li>改变的Fura-2 AM含有媒体孵育后清洗PSS和放置组织，在显微镜下以进一步执行萤光成像。 </li><li>打开CCD相机和稳定的光源（单色系统）配备了滤光轮（每个过滤器的位置可以有自己的衰减水平，选择每一个过滤器被调用时，相关联）。 </li><li>查找在明视场组织。切换到检测荧光信号和调整用中性密度过滤器和灯功率，以避免信号的饱和度的光源的强度。 </li><li>监视与比率激励的组织样品中的Fura-2 AM荧光在三百八十○分之三百四十○纳米，具有0.125 Hz或更高的频率。使用40×/ NA 1.3或类似的物镜正确的解像度化形象。 </li><li>用于图像处理和计算导入图像序列。确保分裂渠道和使用hyperstack灰度模式。选择几个感兴趣的区域（单囊细胞或囊状组织选定的区域），并计算强度值每通道（340和380纳米）转换成首选数据分析软件;减法背景的强度值从每个数据点。 </li><li>对于每个时间点计算出的Fura-2 AM 340〜380信道的强度的比率。地块分散/的钙瞬变每个地区的线路点时间的变化，并计算平均值/ SE值。 </li></ol>

The authors have nothing to disclose.

我们在这里描述的传统膜片钳技术和表面荧光钙成像的应用程序从ARPKD的鼠的遗传模型导出囊性上皮单层。该协议包括三个步骤，其中最应引起重视的囊肿（协议节的步骤1.5）的隔离和电生理研究。这些关键步骤需要大量的训练和耐心，读者不应该立刻感到沮丧。 首先，最要注意的囊肿单层隔离的过程。制备的这一部分需要手工技巧和显著影响进一步的工作，作为检体和其连...

离子通道在许多生理功能，包括细胞生长和分化中发挥显著作用。常染色体显性和隐性多囊肾疾病（ADPKD和ARPKD，分别）是其特征在于，所述的肾小管上皮细胞起源的肾流体填充囊肿的发展遗传性疾病。多囊肾是由PKD1或PKD2编码polycystins 1和参与细胞增殖和分化的调节如图2所示，膜蛋白的突变引起的。 PKD2本身或作为与PKD1一个复杂也发挥作为钙 -permeable阳离子通道1。所述PKHD1基因编码fibrocystin（涉及小管和/或维持上皮极性的纤毛相关受体样蛋白）的突变是ARPKD 2的遗传动力。囊肿生长是一个复杂的现象，伴随着不安扩散3,4，5血管生成，分化和极性损失性肾小管细胞6-8。 有缺陷的再吸收和分泌增强囊性上皮有助于在管腔和囊肿膨胀9,10-流体积聚。受损的流量依赖性钙离子浓度我的信号也已PKD 11-15时挂cystogenesis。 这里，我们描述适用于单通道活性和细胞内Ca 2+水平的囊性上皮单层从PCK大鼠分离的膜片钳测量的方法。这种方法成功地被我们用于表征上皮细胞钠离子通道（ENaC的）10的活性和钙离子浓度依赖我引起的钙 -permeable TRPV4和嘌呤信号级联13处理 。 在这些研究中，我们使用的PCK大鼠，模型ARPKD引起的在PKHD1基因的自发突变。该PCK应变originallÿ从的Sprague-Dawley（SD）大鼠16从而SD大鼠被用作适当的控制用于 ​​与PCK应变比较而得。其结果是，既大鼠肾段和非扩张集合管从同一PCK大鼠分离可以作为两个不同的比较组对囊性上皮实验。

<table border="0" cellpadding="0" cellspacing="0" width="1015">
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		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Fura-2 AM</td>
			<td style="width:219px;">Life Technologies</td>
			<td style="width:183px;">F-14185</td>
			<td style="width:333px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Flou-8</td>
			<td style="width:219px;">AAT Bioquest</td>
			<td style="width:183px;">21091</td>
			<td style="width:333px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Poly-L-lysine</td>
			<td style="width:219px;">Sigma-Aldrich</td>
			<td style="width:183px;">P4707</td>
			<td style="width:333px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Pluronic acid</td>
			<td style="width:219px;">Sigma-Aldrich</td>
			<td style="width:183px;">F-68&#160;</td>
			<td style="width:333px;">solution</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Shaker</td>
			<td style="width:219px;">Boekel Scientific</td>
			<td style="width:183px;">260350</td>
			<td style="width:333px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Light source</td>
			<td style="width:219px;">Sutter Instrument Co</td>
			<td style="width:183px;">Lambda XL</td>
			<td style="width:333px;">with integrated shutter/filter wheel driver</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Neutral density filters</td>
			<td style="width:219px;">Nikon</td>
			<td style="width:183px;"></td>
			<td style="width:333px;">ND4, ND8</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Objective</td>
			<td style="width:219px;">Nikon</td>
			<td style="width:183px;">SFluo&#160;</td>
			<td style="width:333px;">40/1.3 DIC WD 0.22&#160;&#160; oil</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Camera</td>
			<td style="width:219px;">Andor Technologies</td>
			<td style="width:183px;">Zyla sCMOS</td>
			<td style="width:333px;"></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;width:283px;">Nikon&#160; microscope (inverted)</td>
			<td style="width:219px;">Nikon</td>
			<td style="width:183px;">Nikon Eclipse TE2000-S</td>
			<td style="width:333px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Cover Glass</td>
			<td style="width:219px;">Thermo Scientific</td>
			<td style="width:183px;">6661B52</td>
			<td style="width:333px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Diamond pencil</td>
			<td style="width:219px;">Fisher Scientific</td>
			<td style="width:183px;">22268912</td>
			<td style="width:333px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Image acquisition software</td>
			<td style="width:219px;">Nikon</td>
			<td style="width:183px;">Nikon NIS-Elements&#160;</td>
			<td style="width:333px;"></td>
		</tr>
		<tr height="41">
			<td height="41" style="height:41px;width:283px;">Image analysis software</td>
			<td style="width:219px;">ImageJ</td>
			<td style="width:183px;">http://imagej.nih.gov/</td>
			<td style="width:333px;">ND Utility plugin allows to import images in the native Nikon Instruments .nd2 format</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Recording/perfusion chamber</td>
			<td style="width:219px;">Warner Instruments</td>
			<td style="width:183px;">RC-26</td>
			<td style="width:333px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;"></td>
			<td style="width:219px;"></td>
			<td style="width:183px;"></td>
			<td style="width:333px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Patch Clamp amplifier</td>
			<td style="width:219px;">Molecular Devices</td>
			<td style="width:183px;">MultiClamp 700B</td>
			<td style="width:333px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Data Acquisition System</td>
			<td style="width:219px;">Molecular Devices</td>
			<td style="width:183px;">Digidata 1440A</td>
			<td style="width:333px;">Axon Digidata&#174; System</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Low Pass Filter</td>
			<td style="width:219px;">Warner Instruments</td>
			<td style="width:183px;">LPF-8</td>
			<td style="width:333px;">8 pole Bessel</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Borosilicate glass capillaries</td>
			<td style="width:219px;">World Precision Instruments</td>
			<td style="width:183px;">1B150F-4</td>
			<td style="width:333px;"></td>
		</tr>
		<tr height="29">
			<td height="29" style="height:29px;width:283px;">Micropipette Puller</td>
			<td style="width:219px;">Sutter Instrument Co</td>
			<td style="width:183px;">P-97</td>
			<td style="width:333px;">Flaming/Brown type micropipette puller</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Microforge</td>
			<td style="width:219px;">Narishige</td>
			<td style="width:183px;">MF-830</td>
			<td style="width:333px;">Japan</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Motorized Micromanipulator</td>
			<td style="width:219px;">Sutter Instrument Co</td>
			<td style="width:183px;">MP-225</td>
			<td style="width:333px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Inverted microscope</td>
			<td style="width:219px;">Nikon</td>
			<td style="width:183px;">Eclipse Ti</td>
			<td style="width:333px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Microvibration isolation table</td>
			<td style="width:219px;">TMC</td>
			<td style="width:183px;"></td>
			<td style="width:333px;">equipped with Faraday cage</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Multichannel valve perfusion system</td>
			<td style="width:219px;">AutoMake Scientific</td>
			<td style="width:183px;">Valve Bank II</td>
			<td style="width:333px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Recording/perfusion chamber</td>
			<td style="width:219px;">Warner Instruments</td>
			<td style="width:183px;">RC-26</td>
			<td style="width:333px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Software</td>
			<td style="width:219px;">Molecular Devices</td>
			<td style="width:183px;">pClamp 10 . 2</td>
			<td style="width:333px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;"></td>
			<td style="width:219px;"></td>
			<td style="width:183px;"></td>
			<td style="width:333px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Temperature controlled surgical table&#160;</td>
			<td style="width:219px;">MCW core</td>
			<td style="width:183px;"></td>
			<td style="width:333px;">for rodents</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Binocular stereomicroscope</td>
			<td style="width:219px;">Nikon</td>
			<td style="width:183px;">SMZ745</td>
			<td style="width:333px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Syringe pump-based perfusion system</td>
			<td style="width:219px;">Harvard Apparatus</td>
			<td style="width:183px;"></td>
			<td style="width:333px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">polyethylene tubing</td>
			<td style="width:219px;">Sigma-Aldrich</td>
			<td style="width:183px;">PE50</td>
			<td style="width:333px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:283px;">Isofluorane anesthesia</td>
			<td style="width:219px;"><a href="http://www.vetequip.com/">http://www.vetequip.com/</a></td>
			<td style="width:183px;">911103</td>
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			<td height="21" style="height:21px;width:283px;">Other basic reagents</td>
			<td style="width:219px;">Sigma-Aldrich</td>
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			<td></td>
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implementing patch clamp and live fluorescence microscopy to monitor functional properties of freshly isolated pkd epithelium

期间多囊肾囊肿萌生和扩展是一个复杂的过程，其特征在肾小管细胞增殖，管腔流体积累和细胞外基质的形成异常。离子通道和细胞内钙信号的活动是决定的肾小管上皮细胞功能的关键生理参数。我们开发适合于实时观察离子通道的活性与在上皮单层从肾囊肿新鲜分离的细胞内Ca 2+水平膜片钳技术和登记的方法。 PCK大鼠的常染色体隐性遗传性多囊肾病（ARPKD）遗传模型，这里被用作离子通道和钙流的体外分析。这里描述的是详细的一步一步的步骤旨在隔离囊性单层和非扩张管从PCK或正常只SD（SD）大鼠，并监视单通道活性和细胞内Ca 2+动力学。此方法不需要酶加工，并允许在分析新鲜分离的上皮单层的天然环境。此外，这种技术是将细胞内钙的变化非常敏感，并生成高分辨率的图像进行精确的测量。最后，分离的囊性上皮可进一步用于与抗体或染料，制备原代培养物的纯化和关于各种生化分析染色。

潜在的ENaC参与cystogenesis已经证明了几项研究观察到了破坏表皮生长因子（EGF）在PKD进展22-25和异常钠重吸收在ARPKD鼠模型和组织培养26-28信令。例如，Veizis 等人表明，阿米洛利敏感的 Na +吸收在光盘细胞ARPKD 29的非直系同源BPK小鼠模型下降。我们最近证明，受损的钠和水的重吸收的孢囊是在加重cystogenesis 10的一个重要因素。具体来说，我们采用电生理...

Watch this Scientific Journal Video about Implementing Patch Clamp and Live Fluorescence Microscopy to Monitor Functional Properties of Freshly Isolated PKD Epithelium at JoVE.com

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

表现在肾小管上皮细胞离子通道在多囊肾病的病理一个显著的作用。这里，我们描述用于执行囊性上皮从啮齿动物肾脏新鲜分离的膜片钳分析和细胞内钙水平的测量的实验方案。

实施膜片钳和活荧光显微镜监视新鲜分离的PKD上皮细胞的功能特性

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

implementing-patch-clamp-live-fluorescence-microscopy-to-monitor

Research

JoVE Journal

Biology

9.7K 次观看.  Medical College of Wisconsin. 表现在肾小管上皮细胞离子通道在多囊肾病的病理一个显著的作用。这里，我们描述用于执行囊性上皮从啮齿动物肾脏新鲜分离的膜片钳分析和细胞内钙水平的测量的实验方案。 

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

Methods for Patch Clamp Capacitance Recordings from the Calyx

We demonstrate the basic techniques for presynaptic patch clamp recording at the calyx of Held, a mammalian central nervous system nerve terminal. Electrical recordings from the presynaptic terminal allow the measurement of action potentials, calcium channel currents, vesicle fusion (exocytosis) and subsequent membrane uptake (endocytosis). The fusion of vesicles containing neurotransmitter causes the vesicle membrane to be added to the cell membrane of the calyx. This increase in the amount of cell membrane is measured as an increase in capacitance. The subsequent reduction in capacitance indicates endocytosis, the process of membrane uptake or removal from the calyx membrane. Endocytosis, is necessary to maintain the structure of the calyx and it is also necessary to form vesicles that will be filled with neurotransmitter for future exocytosis events. Capacitance recordings at the calyx of Held have made it possible to directly and rapidly measure vesicular release and subsequent endocytosis in a mammalian CNS nerve terminal. In addition, the corresponding postsynaptic activity can be simultaneously measured by using paired recordings. Thus a complete picture of the presynaptic and postsynaptic electrical activity at a central nervous system synapse is achievable using this preparation. Here, the methods for slice preparation, morphological features for identification of calyces of Held, basic patch clamping techniques, and examples of capacitance recordings to measure exocytosis and endocytosis are presented.

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

膜片钳从花萼电容录音方法

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

科研

生物学

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.

补丁钳爪蟾卵母细胞中表达的离子通道

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

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.

改进的膜片钳记录的压力抛光移液器

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

Time-lapse Imaging of Mitosis After siRNA Transfection

Changes in cellular organization and chromosome dynamics that occur during mitosis are tightly coordinated to ensure accurate inheritance of genomic and cellular content. Hallmark events of mitosis, such as chromosome movement, can be readily tracked on an individual cell basis using time-lapse fluorescence microscopy of mammalian cell lines expressing specific GFP-tagged proteins. In combination with RNAi-based depletion, this can be a powerful method for pinpointing the stage(s) of mitosis where defects occur after levels of a particular protein have been lowered. In this protocol, we present a basic method for assessing the effect of depleting a potential mitotic regulatory protein on the timing of mitosis. Cells are transfected with siRNA, placed in a stage-top incubation chamber, and imaged using an automated fluorescence microscope. We describe how to use software to set up a time-lapse experiment, how to process the image sequences to make either still-image montages or movies, and how to quantify and analyze the timing of mitotic stages using a cell-line expressing mCherry-tagged histone H2B. Finally, we discuss important considerations for designing a time-lapse experiment. This strategy is complementary to other approaches and offers the advantages of 1) sensitivity to changes in kinetics that might not be observed when looking at cells as a population and 2) analysis of mitosis without the need to synchronize the cell cycle using drug treatments. The visual information from such imaging experiments not only allows the sub-stages of mitosis to be assessed, but can also provide unexpected insight that would not be apparent from cell cycle analysis by FACS.

Here we describe a basic protocol to image and quantify the mitotic timing of live mammalian tissue culture cells after siRNA transfection.

有丝分裂的siRNA转染后的时间推移成像

Changes in cellular organization and chromosome dynamics that occur during mitosis are tightly coordinated to ensure accurate inheritance of genomic and ...

Fluorescence-based Measurement of Store-operated Calcium Entry in Live Cells: from Cultured Cancer Cell to Skeletal Muscle Fiber

Store operated Ca2+ entry (SOCE), earlier termed capacitative Ca2+ entry, is a tightly regulated mechanism for influx of extracellular Ca2+ into cells to replenish depleted endoplasmic reticulum (ER) or sarcoplasmic reticulum (SR) Ca2+ stores1,2. Since Ca2+ is a ubiquitous second messenger, it is not surprising to see that SOCE plays important roles in a variety of cellular processes, including proliferation, apoptosis, gene transcription and motility. Due to its wide occurrence in nearly all cell types, including epithelial cells and skeletal muscles, this pathway has received great interest3,4. However, the heterogeneity of SOCE characteristics in different cell types and the physiological function are still not clear5-7.
The functional channel properties of SOCE can be revealed by patch-clamp studies, whereas a large body of knowledge about this pathway has been gained by fluorescence-based intracellular Ca2+ measurements because of its convenience and feasibility for high-throughput screening. The objective of this report is to summarize a few fluorescence-based methods to measure the activation of SOCE in monolayer cells, suspended cells and muscle fibers5,8-10. The most commonly used of these fluorescence methods is to directly monitor the dynamics of intracellular Ca2+ using the ratio of F340nm and F380nm (510 nm for emission wavelength) of the ratiometric Ca2+ indicator Fura-2. To isolate the activity of unidirectional SOCE from intracellular Ca2+ release and Ca2+ extrusion, a Mn2+ quenching assay is frequently used. Mn2+ is known to be able to permeate into cells via SOCE while it is impervious to the surface membrane extrusion processes or to ER uptake by Ca2+ pumps due to its very high affinity with Fura-2. As a result, the quenching of Fura-2 fluorescence induced by the entry of extracellular Mn2+ into the cells represents a measurement of activity of SOCE9. Ratiometric measurement and the Mn+2 quenching assays can be performed on a cuvette-based spectrofluorometer in a cell population mode or in a microscope-based system to visualize single cells. The advantage of single cell measurements is that individual cells subjected to gene manipulations can be selected using GFP or RFP reporters, allowing studies in genetically modified or mutated cells. The spatiotemporal characteristics of SOCE in structurally specialized skeletal muscle can be achieved in skinned muscle fibers by simultaneously monitoring the fluorescence of two low affinity Ca2+ indicators targeted to specific compartments of the muscle fiber, such as Fluo-5N in the SR and Rhod-5N in the transverse tubules9,11,12.

The extent of store-operated Ca2+ entry (SOCE) can be monitored using fluorescent Ca2+ indicators. Mn2+ quenching of such indicators assays SOCE in cultured cells and skeletal muscle fibers. A technique allowing spatial and temporal resolution of SOCE by confocal imaging of mechanically skinned muscle fibers is also described.

基于荧光测定活细胞中的钙进入商店经营：从培养的肿瘤细胞，骨骼肌纤维

Store operated Ca2+ entry (SOCE), earlier termed capacitative Ca2+ entry, is a tightly regulated mechanism for influx of extracellular Ca2+ into cells to ...

Quantitative Live Cell Fluorescence-microscopy Analysis of Fission Yeast

Several microscopy techniques are available today that can detect a specific protein within the cell. During the last decade live cell imaging using fluorochromes like Green Fluorescent Protein (GFP) directly attached to the protein of interest has become increasingly popular 1. Using GFP and similar fluorochromes the subcellular localisations and movements of proteins can be detected in a fluorescent microscope. Moreover, also the subnuclear localisation of a certain region of a chromosome can be studied using this technique. GFP is fused to the Lac Repressor protein (LacR) and ectopically expressed in the cell where tandem repeats of the lacO sequence has been inserted into the region of interest on the chromosome2. The LacR-GFP will bind to the lacO repeats and that area of the genome will be visible as a green dot in the fluorescence microscope. Yeast is especially suited for this type of manipulation since homologous recombination is very efficient and thereby enables targeted integration of the lacO repeats and engineered fusion proteins with GFP 3. Here we describe a quantitative method for live cell analysis of fission yeast. Additional protocols for live cell analysis of fission yeast can be found, for example on how to make a movie of the meiotic chromosomal behaviour 4. In this particular experiment we focus on subnuclear organisation and how it is affected during gene induction. We have labelled a gene cluster, named Chr1, by the introduction of lacO binding sites in the vicinity of the genes. The gene cluster is enriched for genes that are induced early during nitrogen starvation of fission yeast 5. In the strain the nuclear membrane (NM) is labelled by the attachment of mCherry to the NM protein Cut11 giving rise to a red fluorescent signal. The Spindle Pole body (SPB) compound Sid4 is fused to Red Fluorescent Protein (Sid4-mRFP) 6. In vegetatively growing yeast cells the centromeres are always attached to the SPB that is embedded in the NM 7. The SPB is identified as a large round structure in the NM. By imaging before and 20 minutes after depletion of the nitrogen source we can determine the distance between the gene cluster (GFP) and the NM/SPB. The mean or median distances before and after nitrogen depletion are compared and we can thus quantify whether or not there is a shift in subcellular localisation of the gene cluster after nitrogen depletion.

The fission yeast, Schizosaccharomyces pombe, is a good model system to study basic cellular processes. Here we describe a method to perform quantitative live cell analysis of fission yeast. In this particular experiment we focus on organisation of the genome within the cell nucleus, but the method can also be used to study cytosolic factors.

裂殖酵母的活细胞定量荧光显微镜分析

Several microscopy techniques are available today that can detect a specific protein within the cell. During the last decade live cell imaging using ...

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.

巨脂质体制剂成像和膜片钳电

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.

单通道细胞贴附膜片钳记录

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.

跨膜蛋白的重组，电压门控离子通道，KvAP，进入巨人单层囊的显微镜和膜片钳研究

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

Single-channel Analysis and Calcium Imaging in the Podocytes of the Freshly Isolated Glomeruli

Podocytes (renal glomerular epithelial cells) are known to regulate glomerular permeability and maintain glomerular structure; a key role for these cells in the pathogenesis of various renal diseases has been established since podocyte injury leads to proteinuria and foot process effacement. It was previously reported that various endogenous agents may cause a dramatic overload in intracellular Ca2+ concentration in podocytes, presumably leading to albuminuria, and this likely occurs via calcium-conducting ion channels. Therefore, it appeared important to study calcium handling in the podocytes both under normal conditions and in various pathological states. However, available experimental approaches have remained somewhat limited to cultured and transfected cells. Although they represent a good basic model for such studies, they are essentially extracted from the native environment of the glomerulus. Here we describe the methodology of studying podocytes as a part of the freshly isolated whole glomerulus. This preparation retains the functional potential of the podocytes, which are still attached to the capillaries; therefore, podocytes remain in the environment that conserves the major parts of the glomeruli filtration apparatus. The present manuscript elaborates on two experimental approaches that allow 1) real-time detection of calcium concentration changes with the help of ratiometric confocal fluorescence microscopy, and 2) the recording of the single ion channels activity in the podocytes of the freshly isolated glomeruli. These methodologies utilize the advantages of the native environment of the glomerulus that enable researchers to resolve acute changes in the intracellular calcium handling in response to applications of various agents, measure basal concentration of calcium within the cells (for instance, to evaluate disease progression), and assess and manipulate calcium conductance at the level of single ion channels.

Changes in the intracellular calcium levels in the podocytes are one of the most important means to control the filtration function of glomeruli. Here we explain a high-throughput approach that allows detection of real-time calcium handling and single ion channels activity in the podocytes of the freshly isolated glomeruli.

单通道分析和钙成像在新鲜分离的肾小球足细胞

Podocytes (renal glomerular epithelial cells) are known to regulate glomerular permeability and maintain glomerular structure; a key role for these cells ...