Funding was provided by the Austrian Science Fund FWF grant No. P-22969-B11 to F. Ferraguti, and by the Charitable Hertie Foundation and the Werner Reichardt Centre for Integrative Neuroscience and by the DFG (CIN-Exc. 307) to I. Ehrlich.

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The authors declare that they have no competing financial interests.

冷冻断裂电子显微镜已在超微结构研究的重大技术超过40年。然而，由于缺乏有效的手段来研究膜的分子组成产生了它的使用显著下跌。近来，出现了在冷冻断裂电子显微术的一个主要复兴由于通过免疫标记1,2，即FRIL技术以显示完整的膜蛋白的有效方法的发展。 该FRIL技术比其他免疫超微结构方法具有几个优点。首先，蛋白质是抗体增加的敏感度容易接近。第二，细胞膜特，如突触后膜，副本的二维表面上的大的部分的曝光允许感兴趣的分子的空间分布和物理邻接的检查而不斯里的费力和耗时的重建人超薄切片。第三，质膜的两半的可用性增加了可被标记为每个单独的结构蛋白的数量，提供合适的抗体是可用的。在压裂，分裂膜的疏水面涂覆有碳 - 铂该entrenches残留在断裂表面上的蛋白质结构域。这可以防止在这些结构域抗原的抗体的访问。例如在一个复制品的P面仅面向原浆空间表位可以通过抗体而在E-面仅表位朝向可被抗体结合的exoplasmic空间进行检测，（ 见图2）。 在另一方面，FRIL技术也从一定的局限性2受损。由于骨折随机发生的，它可能是很难瞄准特定的细胞或结构。这也可能导致一个抽样偏差， 例如，突触集合中，考虑到不同的概率离的沿结构具有不同的曲率（ 例如，刺对轴）的膜cturing。此外，膜蛋白的两个面中的一个的分配是不可预测的。因此，蛋白质为P-面或E-面的分布，特别是用于定量研究，应认真使用抗体反应的细胞内和细胞外结构域检查。最后，在某些结构，例如突触前轴突终端的复制品的识别，仅基于形态特征时是很困难的。然而，对于标志蛋白的特异性抗体的使用或标记整合膜蛋白或使用病毒载体提供额外的工具通道的转导，以便于裂隙膜的鉴定。例如，本研究了的ChR2-YFP的丘脑神经元的转导的优点，以确定他们的轴突传出神经在杏仁核或标记为μ阿片受体揭示突触后箱ITC神经元mbranes。 为了成功地进行FRIL技术，应特别注意关于组织固定服用。强组织固定（&gt; 2％多聚甲醛）可导致交叉骨折率很高，并在贴标签的灵敏度的降低。另一方面，弱注视使组织处理和加工（ 例如，切割部分）的困难。同样重要的是，以控制修剪块的厚度的双面胶带的厚度相匹配。如果检体的厚度比带的下部，所述组织的表面可能不附着到两个金属载体的表面上，从而将冷冻试样不破裂。如果组织是厚，它会与不可避免结构扭曲压缩两个铜载波的三明治制成时。在该试样断裂（在此协议-115℃，）中的温度也起着重要的作用上的副本的结构。较高的温度可能会产生伪像的一个更高的速率，如在组织的表面上的水蒸汽的冷凝之前或蒸发期间。较低的温度（&lt;-125℃）压裂过程中可能会增加分裂的危险掉的材料。这种材料可落入到样品的表面上或保持连接到它。材料的这些片也铜版纸和对比产生图像上的黑斑。在较低温度下压裂也可以影响交骨折的频率特别是对于小的精细结构如树突棘。在副本的制备进一步关键步骤是该洗涤剂消化。如果消化不完全，未消化的组织出现在副本的暗斑，在TEM混杂结构的分析。此外，未消化的组织可以非特异性陷阱或绑定的抗体，增加了背景标记。另一方面，使用洗涤剂的S表示组织消化可变性关联到副本改变其二级和三级结构的分子。因此，对于某些抗原可能需要逐渐稀释SDS浓度额外洗涤步骤。 对于免疫标记，不同大小的缀合到二级抗体的金颗粒的可用性允许在同一时间进行检测，但只有定性，多种蛋白质，甚至在质膜的特定微区，如突触后专业化。然而，由于空间位阻，定量研究一般仅限于在检测只有一个分子。前述金颗粒的尺寸也可影响标签功效。 在FRIL标记的解释，应该记住的是，在免疫粒子可位于任何地方与从该抗原20-25纳米的半径的半球内由于柔性复杂的形式由初级和二级抗体26编有关理论和FRIL及其相关技术的实践提供进一步的信息，我们将为读者也给其他方法的第27条，28。 的FRIL技术最近已用于在不同的突触种群29,30。此外，AMPA-Rs中的FRIL技术的检测灵敏度估计高达每一个功能的AMPA 1免疫粒子谷氨酸受体定 ​​位的高分辨率定量分析-R通道29。因此，这种方法是整体非常有用的量化和分析AMPA-R和NMDA-R的在中央突触突触后表达的图案。在这里，我们展示了其在PIN / MGN-ITC突触适用性，一个网站最有可能的，生怕调节过程中传达美国的信息很重要。使用针对AMPA受体亚基谷氨酸的高度保守的细胞外的氨基酸残基产生的抗体A1-GluA4，我们发现对应于突触后膜专业进出口集群内连金颗粒的分布。相比于通过PIN / MGN丘脑传入针对性轴突触AMPA-R的在ITC棘密度为显著高。在两个脊柱和轴突触，检测标记为AMPA-R和突触后区之间的正相关性，常见于其他谷氨酸突触25的功能。在PIN / MGN-ITC突触AMPA-R的密度低方差指示类似于丘脑传出神经形成7突触等，但不同于皮层突触25的均匀分布。相反，NMDA-R的密度为更多变和脊椎和轴突触暗示比AMPA-R的不同规定之间没有差异。在未来，FRIL技术的高再现性将不仅允许评估中央突触的基础分子组成，但可有利于的c检测hanges在离子型谷氨酸受体的数量和分布subsynaptic恐惧学习后，补充这些投入前和突触后性能的离体记录。 总之，这种方法可以由其他研究者用来洞察特定输入兴奋性突触的结构与功能的关系中的许多其他的神经回路，其中解开输入的原点和突触后元件的性质和组合物是至关重要的，但问题。

生物膜在纳米尺度的功能结构的定义已经由许多适于透射电镜免疫标记技术的发展，近年来挑战。然而，这些技术， 例如，前和后包埋免疫，有一些重要的限制，其中包括检测差抗原和/或膜结合蛋白的有限定量的评估。这些限制成为在神经系统中，其特点是具有高度细胞多样性和突触异质性的精细结构的调查尤为关键。这种异质性的结果从由前和突触后的元素和由差异表达，富集，或信号蛋白，如受体，转运，和效应分子的相互作用所决定的结构和功能的多样性。 直接immunolabe的新方法在洗涤剂溶解的冷冻断裂副本（FRIL）积分或交联的膜蛋白的灵最初是由藤本介绍二十年前1。这种原始的方法有，然而，一些限制， 即，复制品，这阻碍了在复杂的组织分别映射细胞如脑标记分子的有意义的相关性的严重碎裂。大约10年前，茂 ​​源和深泽逐步提高技术2。这是通过从另一组在科罗拉多州立大学的博尔德实验室，谁也显著提高的技术中，特别是用于间隙连接3的研究科学家努力平行。 在冷冻压裂协议和机器的改进，以及引入快速冷冻的（在高压下），现在允许调查者产生的相对大的尺寸和标本不间断复制品喜大多数细胞成分的GH品质的图像，而不限制和强大的化学生产的注视文物。 的FRIL技术提供一个高度定量的很大的优点，在映射组织学一种或多种蛋白质（同时）和细胞学鉴定细胞复合组织内，如大脑的原位鉴别，与前和突触后的平面视图的额外的优点在一个单一的复制品的元件。因此，FRIL技术，尽管它的许多技术难题，适用于一些非常显著科学突破的承诺，尤其是对个别突触的结构和功能特性的相关性。在过去的几十年里，已获得的大量信息的结构，分子组成，与突触的生理功能;但突触在形态和分子高度多样化取决于前和突触后PA租金神经元4。仅适用于突触类型的少数人结构与功能的研究，到目前为止5-7完成。这主要是由于该防止前和突触后元件的性质的精确识别技术约束。 超微结构分析提供了关键见解跨越不同突触联系两个突触大小和内容方面突触后膜特化在神经递质受体6的可变性，这对突触传递的强度和可塑性很大的影响。此外，大量的研究表明，在不同类型的突触表达离子型谷氨酸受体的数量在afferent-和目标依赖的方式7-10调节。 这里，一个方法概述允许突触后膜特化的结构和受体组成的分析与限定ð突触前元件和功能。这种方法需要最近开发的光敏感藻蛋白，如channelrhodopsin2（的ChR2）的突触前表达的优点，并且FRIL技术来分析的α氨基-3-羟基-5-甲基-4-异唑突触后表达的图案酸（AMPA-RS）和N-甲基-D-天冬氨酸（NMDA-RS）谷氨酸受体。这表现在从后丘脑，内侧膝状核（PIN / MGN）始发到杏仁核（ITC）的插层细胞群众的神经元轴突形成突触。 ITC神经元是在围绕基底外侧杏仁络合物（BLA）11,12簇组织小刺的GABA能细胞。ITC神经元已知从BLA主要神经元接收兴奋性输入和定位的中央核（CEA），从而作为抑制栅极运作对信息的BLA和CEA 12-15之间流动。 最近，我们证明了IT位于BLA和CEA之间的内-背集群用C神经元也收到来自感官丘脑及颞皮层区域，这是在巴甫洛夫的听觉恐惧条件16期间学习的恐惧直接修改和收敛的兴奋性投入。恐惧空调是联想学习的大脑机制方面的最好理解的形式之一。在恐惧条件，最初的中性条件刺激（CS， 例如，一个音）是搭配厌恶非条件刺激（US， 例如，一个温和的脚震动）造成了CS-美国协会和空调的恐惧反应17，18。兴奋来自丘脑和新皮质区，其中携带表示CS和美国信息输入，分别被称为会聚到杏仁核（LA）的外侧核的锥体神经元和经受塑性19。我们以前的工作表明，感觉输入的信息也传达给ITC的神经元并行<s达&gt; 16。 作为对个体感觉输入的一种机械的分子分析的第一步突触到ITC神经元，我们使用腺伴随病毒（AAV）来表达的ChR2标记与黄色荧光蛋白（YFP）。所述AAV注入PIN / MGN和轴突终端被他们的ChR2-YFP的表达鉴定。我们所使用的FRIL技术生成两个面，以评估在与ITC神经元的PIN / MGN轴突终末形成突触的突触后AMPA-R和NMDA-Rs的密度。

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td colspan="4">Surgery</td>
		</tr>
		<tr>
			<td>Stereotactic frame</td>
			<td>Stoelting, USA</td>
			<td>51670</td>
			<td>can be replaced by other stereotactic frame for mice</td>
		</tr>
		<tr>
			<td>Steretoxic frame mouse adaptor</td>
			<td>Stoelting, USA</td>
			<td>51625</td>
			<td></td>
		</tr>
		<tr>
			<td>Gas anesthesia mask for mice</td>
			<td>Stoelting, USA</td>
			<td>50264</td>
			<td>no longer available, replaced by item no. 51609M</td>
		</tr>
		<tr>
			<td>Pressure injection device, Toohey Spritzer</td>
			<td>Toohey Company, USA</td>
			<td>T25-2-900</td>
			<td>other pressure injection devices (e.g. Picospritzer) can be used</td>
		</tr>
		<tr>
			<td>Kwik Fill glass capillaries</td>
			<td>World Precision Instruments, Germany</td>
			<td>1B150F-4</td>
			<td></td>
		</tr>
		<tr>
			<td>Anesthesia machine, IsoFlo</td>
			<td>Eickemeyer, Germany</td>
			<td>213261</td>
			<td></td>
		</tr>
		<tr>
			<td>DC Temperature Controler and heating pad</td>
			<td>FHC, USA</td>
			<td>40-90-8D</td>
			<td></td>
		</tr>
		<tr>
			<td>Horizontal Micropipette Puller Model P-1000</td>
			<td>Sutter Instruments, USA</td>
			<td>P-1000</td>
			<td></td>
		</tr>
		<tr>
			<td>Surgical tool sterilizer, Sterilizator 75</td>
			<td>Melag, Germany</td>
			<td>08754200</td>
			<td></td>
		</tr>
		<tr>
			<td>rAAV-hSyn-ChR2(H134R)-eYFP (serotype 2/9)</td>
			<td>Penn Vector Core, USA</td>
			<td>AV-9-26973P</td>
			<td></td>
		</tr>
		<tr>
			<td>fast green</td>
			<td>Roth, Germany</td>
			<td>0301.1</td>
			<td></td>
		</tr>
		<tr>
			<td>Isoflurane Anesthetic, Isofuran CP (1ml/ml)</td>
			<td>CP Pharma, Germany</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Antiseptic, Betadine (providone-iodine)</td>
			<td>Purdure Products, USA</td>
			<td>BSOL32</td>
			<td>can be replaced by other disinfectants</td>
		</tr>
		<tr>
			<td>Analgesic, Metacam Solution (5mg/ml meloxicam)</td>
			<td>Boehringer Ingelheim, Germany</td>
			<td></td>
			<td>can be replaced by other analgesics</td>
		</tr>
		<tr>
			<td>Bepanthen eye ointment</td>
			<td>Bayer, Germany</td>
			<td>0191</td>
			<td>can be replaced by other eye ointments</td>
		</tr>
		<tr>
			<td>Drill NM3000 (SNKG1341 and SNIH1681)</td>
			<td>Nouvag, Switzerland</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sutranox Suture Needle</td>
			<td>Fine Science Tools, Germany</td>
			<td>12050-01</td>
			<td></td>
		</tr>
		<tr>
			<td>Braided Silk Suture</td>
			<td>Fine Science Tools, Germany</td>
			<td>18020-60</td>
			<td></td>
		</tr>
		<tr>
			<td>Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td colspan="4">Tissue preparation</td>
		</tr>
		<tr>
			<td>Paraformaldehyde EM grade</td>
			<td>Agar Scientific Ltd., United Kingdom</td>
			<td>AGR1018</td>
			<td></td>
		</tr>
		<tr>
			<td>Saturated picric acid solution</td>
			<td>Sigma-Aldrich, USA</td>
			<td>P6744-1GA</td>
			<td></td>
		</tr>
		<tr>
			<td>Na2HPO4-2H20</td>
			<td>Merck Millipore, Germany</td>
			<td>1065860500</td>
			<td></td>
		</tr>
		<tr>
			<td>NaH2PO4-2H2O&#160;</td>
			<td>Merck Millipore, Germany</td>
			<td>1063451000</td>
			<td></td>
		</tr>
		<tr>
			<td>NaCl</td>
			<td>Merck Millipore, Germany</td>
			<td>1064041000</td>
			<td></td>
		</tr>
		<tr>
			<td>4N NaOH</td>
			<td>Carl Roth, Germany</td>
			<td>T198.1</td>
			<td></td>
		</tr>
		<tr>
			<td>Thiopental</td>
			<td>Sandoz, Austria</td>
			<td>5,133</td>
			<td></td>
		</tr>
		<tr>
			<td>Glycerol</td>
			<td>Sigma-Aldrich, USA</td>
			<td>G5516-500ML</td>
			<td></td>
		</tr>
		<tr>
			<td>GenPure ultrapure water system</td>
			<td>Thermo Fisher Scientific, USA</td>
			<td>50131235</td>
			<td></td>
		</tr>
		<tr>
			<td>Peristaltic pump</td>
			<td>ISMATEC, Germany</td>
			<td>ISM 930C</td>
			<td></td>
		</tr>
		<tr>
			<td>Filter Paper</td>
			<td>MACHEREY-NAGEL, Germany</td>
			<td>MN 615 1/4</td>
			<td></td>
		</tr>
		<tr>
			<td>Vibroslicer, VT1000S</td>
			<td>Leica Microsystems, Austria</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Ophthalmic scalpel</td>
			<td>Alcon Laboratories, USA</td>
			<td></td>
			<td>can be replaced by other ophthalmic scalpels</td>
		</tr>
		<tr>
			<td>Perfusion cannula</td>
			<td>Vieweg, Germany</td>
			<td>F560088-1</td>
			<td>can be replaced by similar items from other companies</td>
		</tr>
		<tr>
			<td>Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td colspan="4">High-pressure&#160; Freezing</td>
		</tr>
		<tr>
			<td>Copper carriers</td>
			<td>Engineering Office M. Wohlwend, CH</td>
			<td>528</td>
			<td></td>
		</tr>
		<tr>
			<td>Sidol Polish</td>
			<td>Henkel, Germany</td>
			<td></td>
			<td>can be replaced by same item from other companies</td>
		</tr>
		<tr>
			<td>Chamois skin</td>
			<td>Household supply store</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Hole punch, 1,5mm</td>
			<td>Stubai, Austria</td>
			<td></td>
			<td>can be replaced by same item from other companies</td>
		</tr>
		<tr>
			<td>Denatured ethanol</td>
			<td>Donauchem, Austria</td>
			<td></td>
			<td>can be replaced by same item from other companies</td>
		</tr>
		<tr>
			<td>Aceton</td>
			<td>Roth, Germany</td>
			<td>9372.5</td>
			<td>CAUTION!</td>
		</tr>
		<tr>
			<td>High Pressure Freezing Machine HPM 010</td>
			<td>BalTec, CH; now Leica Microsystems</td>
			<td>HPM010</td>
			<td>not produced any more, substituted by LeicaEM HPM100</td>
		</tr>
		<tr>
			<td>Stereo-microscope</td>
			<td>Olympus, Japan</td>
			<td>SZX10</td>
			<td></td>
		</tr>
		<tr>
			<td>Liquid nitrogen</td>
			<td></td>
			<td></td>
			<td>CAUTION!</td>
		</tr>
		<tr>
			<td>Cryo-vials</td>
			<td>Roth, Germany</td>
			<td>E309.1</td>
			<td>can be replaced by same item from other companies</td>
		</tr>
		<tr>
			<td>CryoCane</td>
			<td>Nalge Nunc International,USA</td>
			<td>5015-0001</td>
			<td>can be replaced by same item from other companies</td>
		</tr>
		<tr>
			<td>CryoSleeve</td>
			<td>Nalge Nunc International,USA</td>
			<td>5016-0001</td>
			<td>can be replaced by same item from other companies</td>
		</tr>
		<tr>
			<td>Liquid nitrogen storage vessel</td>
			<td>Cryopal, France</td>
			<td>GT38</td>
			<td>can be replaced by same item from other companies</td>
		</tr>
		<tr>
			<td>Non-ionic detergent (Lavocid)</td>
			<td>Werner &#38; Mertz Professional, Germany</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td colspan="4">Freeze-fracture and Replication</td>
		</tr>
		<tr>
			<td>Sandblaster, Mikromat 200-1</td>
			<td>JOKE Joisten &#38; Kettenbaum, Germany</td>
			<td>SANDURET 2-K</td>
			<td>can be replaced by same item from other companies</td>
		</tr>
		<tr>
			<td>Siliciumcarbid SIC 360, grain size 25 - 21&#181;</td>
			<td>JOKE Joisten &#38; Kettenbaum, Germany</td>
			<td>955932</td>
			<td></td>
		</tr>
		<tr>
			<td>Freeze Fracture System BAF 060</td>
			<td>BalTec, CH; now Leica Microsystems</td>
			<td>BAF060</td>
			<td></td>
		</tr>
		<tr>
			<td>Ceramic 12 well plate</td>
			<td>Gr&#246;pel, Austria</td>
			<td>14511</td>
			<td>can be replaced by same item from other companies</td>
		</tr>
		<tr>
			<td>Trizma base</td>
			<td>SIGMA, USA</td>
			<td>T1503</td>
			<td>can be replaced by same item from other companies</td>
		</tr>
		<tr>
			<td>Trizma hydrochloride</td>
			<td>SIGMA, USA</td>
			<td>T3253</td>
			<td>can be replaced by same item from other companies</td>
		</tr>
		<tr>
			<td>Sodium chloride</td>
			<td>Merck, Germany</td>
			<td>1,064,041,000</td>
			<td>can be replaced by same item from other companies</td>
		</tr>
		<tr>
			<td>SDS, Sodium lauryl sulfate</td>
			<td>Roth, Germany</td>
			<td>5136.1</td>
			<td>CAUTION! ;&#160; can be replaced by same item from other companies</td>
		</tr>
		<tr>
			<td>Sucrose</td>
			<td>Merck, Germany</td>
			<td>1,076,871,000</td>
			<td>can be replaced by same item from other companies</td>
		</tr>
		<tr>
			<td>TRIS</td>
			<td>Roth, Germany</td>
			<td>5429.3</td>
			<td>can be replaced by same item from other companies</td>
		</tr>
		<tr>
			<td>Universal Hybridization Oven</td>
			<td>Binder, Germany</td>
			<td>7001-0050</td>
			<td>can be replaced by same item from other companies</td>
		</tr>
		<tr>
			<td>Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td colspan="4">Immunolabelling</td>
		</tr>
		<tr>
			<td>BSA</td>
			<td>SIGMA, USA</td>
			<td>A9647</td>
			<td>can be replaced by same item from other companies</td>
		</tr>
		<tr>
			<td>Anti-GFP Antibody</td>
			<td>Molecular Probes, USA</td>
			<td>A11122</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-pan-AMPAR Antibody</td>
			<td>Frontier Institute, Japan</td>
			<td>pan AMPAR-GP-Af580-1</td>
			<td></td>
		</tr>
		<tr>
			<td>Anti-NMDAR1 Antibody, clone 54.1</td>
			<td>Merck Millipore, Germany</td>
			<td>MAB363</td>
			<td></td>
		</tr>
		<tr>
			<td>Opioid Receptor-Mu (MOR) Antibody</td>
			<td>ImmunoStar, USA</td>
			<td>24216</td>
			<td></td>
		</tr>
		<tr>
			<td>EM goat anti-guinea pig, 5nm; secondary antibody</td>
			<td>BBInternational,</td>
			<td>EM.GAG5</td>
			<td></td>
		</tr>
		<tr>
			<td>EM goat anti-rabbit, 15nm; secondary antibody</td>
			<td>BBInternational,</td>
			<td>EM.GAR15</td>
			<td></td>
		</tr>
		<tr>
			<td>Donkey anti-rabbit, 10nm, secondary antibody</td>
			<td>AURION, Netherlands</td>
			<td>DAR 10nm</td>
			<td></td>
		</tr>
		<tr>
			<td>Copper grids, 100 Parallel Bar</td>
			<td>&#160;Agar scientific, UK</td>
			<td>G2012C</td>
			<td></td>
		</tr>
		<tr>
			<td>Incubator</td>
			<td>Major Science, USA</td>
			<td>MO-RC</td>
			<td>can be replaced by same item from other companies</td>
		</tr>
		<tr>
			<td>Pioloform Powder</td>
			<td>&#160;Agar scientific, UK</td>
			<td>R1275</td>
			<td></td>
		</tr>
		<tr>
			<td>Chloroform</td>
			<td>Roth, Germany</td>
			<td>3313.1</td>
			<td>CAUTION! ;&#160; can be replaced by same item from other companies</td>
		</tr>
		<tr>
			<td>Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td colspan="4">EM analysis</td>
		</tr>
		<tr>
			<td>Philips CM120 TEM</td>
			<td>Philips/FEI</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Morada CCD camera</td>
			<td>Soft Imaging Systems, Germany</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>iTEM Ver. 5.2, imaging software</td>
			<td>Soft Imaging Systems, Germany</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

combined optogenetic and freeze-fracture replica immunolabeling to examine input-specific arrangement of glutamate receptors in the mouse amygdala

冷冻断裂电子显微镜已在超微结构研究的重大技术超过40年。然而，由于缺乏有效的手段来研究膜的分子组成产生了它的使用显著下跌。近来，出现了在冷冻断裂电子显微镜得益于通过免疫标记以显示完整的膜蛋白的有效方法的发展的一个主要的复兴。这些方法之一被称为洗涤剂溶解的冷冻断裂副本免疫标记（FRIL）。 与光遗传学的FRIL技术的组合允许中央突触的结构和功能特性的一个相关的分析。使用这种方法，可以鉴定和由它们各自的一个标记channelrhodopsin的表达和特定的分子标志物表征前和突触后神经元。 glutamat的突触后膜专业化的独特的外观GABA能突触进一步允许，当离子型谷氨酸受体的标记，来量化和分析这些受体的intrasynaptic分布。在这里，我们给的准备配对副本和如何immunolabel它们所需的程序一步一步的说明。我们也将讨论FRIL技术的警告和限制，特别是与潜在的采样偏见有关的。的FRIL技术的高再现性和通用性，当与光遗传学相结合，提供了用于在大脑识别的神经元微电路突触传递的不同方面表征一个非常强大的方法。 在这里，我们提供了一个例子这种方法是如何用在鼠标杏仁核的细胞插群众的神经元洞察兴奋性突触的结构与功能的关系。特别是，我们已经调查离子型谷氨酸受体的表达在确定的输入或从丘脑后部板内核和内侧膝​​状核iginated。这些突触被证明传递感觉信息有关的恐惧学习和对恐惧条件经受塑性变化。

的FRIL技术，当与微生物来源21， 即信道集成在质膜和有效地沿轴突顺行输送的光遗传学致动器的表达相结合，允许在限定的亚组来定量检验AMPA-R和NMDA-Rs的突触后表达突触。这显示在这里从不同丘脑核（如 PIN / MGN）始发到杏仁核神经元ITC轴突。这种方法使个体感觉输入突触到ITC神经元，一组细胞的已耐火仔细的解剖和分子表征到目前为止的分子分析。 立体定向注射的rAAV-的ChR2-YFP的入PIN / MGN 4周后，的ChR2-YFP阳性轴突密集支配洛杉矶，所述amygdalostriatal过渡区域（Astria）和内侧paracapsular我<html>在杏仁核的TC簇，与以前的跟踪完全一致的图案研究16,22。我们还检测到强烈的金上从腺相关病毒的ChR2-YFP-在冷冻断裂复制品轴突和终端的P-面免疫标记为的ChR2-YFP注射的小鼠（ 图5A），但不是从非注射的小鼠的副本。在一个复制品谷氨酸突触的突触后膜专业化可以观察到作为质膜2，23的E-面膜内颗粒（IMP）中的集群，并且常伴有其突触前质膜7的P面（ 图5B-C）。允许识别由PIN / MGN轴突终末形成谷氨酸突触的突触后专业化这些功能（ 图5和6）。我们标记AMPA-R的与识别所有四个亚基（GluA1-4），而使用抗必要NR1亚基的抗体检测NMDA-R的抗体。 ntent"FO:保together.within页="1"&gt;由于缺乏工具来检测相同的副本是否这些突触用树突棘或ITC神经元的轴做，我们标注相应的副本脸μ阿片受体，作为ITC的神经元表达突触后高水平这些受体24，这使用了采用标策略所需的相同的突触后轮廓的识别的两个副本（ 图5C-F和图6A-D）（ 图4E） 。 <img alt="图5" src="/files/ftp_upload/53853/53853fig5.jpg" /> 图5的ChR2-YFP和离子型谷氨酸受体的检测通过免疫颗粒副本。（A）横断裂轴突终端（浅蓝色）和标记有15nm的金颗粒检测的ChR2-YFP其P-面的一小部分。在终端内，膜Ô˚F众多突触小泡可以观察（SV）。注意免疫标记的限制的质膜很大一部分的特异性。标记为的ChR2识别终端作为从PIN / MGN始发。该终端形成具有脊的不对称突触。突触后膜专业化（PSD）在E-面显示膜内粒子的特性簇，并标记为5nm的金颗粒揭示AMPA-卢比。 （B）一种的ChR2表达轴突（标有15纳米的金颗粒）的P面所示接壤2树突的它们具有标记为5nm的金颗粒露出的NMDA-R的2的PSD之一。 （CD）一个PIN / MGN-ITC突触前和突触后膜的相对面。 （C）的端子的P面表达的ChR2（标有15纳米的金粒子）并延伸超过两树突轴，包含标记为AMPA-卢比（5纳米的金颗粒）二的PSD其中之一的E面。 （ <strong&gt;的D）的两个树突的相应的P-面标记为μ阿片受体（10纳米的金粒子）。 （EF）由虚线所概述的区域的放大图。比例尺:500纳米<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/53853/53853fig5large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> 为在PIN / MGN-ITC突触AMPA-卢比Immunoparticles发现所有的IMP簇以上，这表明突触后专业化（ 图5E）中的均匀分布。在PIN / MGN观察到显著较高（非配对t检验P &lt;0.018）AMPA-R标记密度突触到ITC棘（715±38金颗粒/微米2，N = 32）相比，突触到ITC树突（590 ±44金颗粒/微米2，N = 32）。总体而言，在PIN / MGN-ITC突触AMPA-R的密度呈相对较低方差（方差的系数，CV = 0.37）与均匀分布是一致的。 为在PIN / MGN-ITC突触的NMDA-R的Immunoparticles常常突触后的IMP簇（ 图5B）内观察到的分布不均。 NMDA-R标记的密度相似（非配对t检验p = 0.39）之间的PIN / MGN突触到ITC棘（1070±153金颗粒/微米2，N = 8）和ITC树突（812±183金粒子/微米2，N = 9）。不像所观察为AMPA-卢比，在PIN / MGN-ITC突触的NMDA-Rs的密度是高度变量（CV = 0.54）。 <img alt="图6" src="/files/ftp_upload/53853/53853fig6.jpg" /> 图6. AMPA-R和NMDA-R的免疫标记在鉴定PIN / MGN-ITC突触。 （AB）一个PIN / MGN-ITC的前和突触后膜的相对面作出到树突棘其中终端的P面表达的ChR2突触（标有15纳米的金颗粒）和在PSD到树突棘标记为AMPA-卢比（5纳米金粒子）。 （CD）由虚线所概述的区域的放大图。这些区域已经被旋转约45°逆时针允许的PSD更好的视野。 （E） - AMPA-R颗粒对在ITC的脊骨和树突突触区的数目的散点图。在这两种结构中，一个正相关已经观察到。 （F）对在ITC刺和树突突触区的NMDA-R的粒子数的散点图。检测只在树突棘一个显著的正相关关系。比例尺:500纳米<a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/53853/53853fig6large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> 因为部分常常覆盖在突触后的IMP簇突触前质膜的P面，我们可以估算的只有30％的突触的突触区（棘:平均面积0.032微米2，范围:0.007〜0.063微米2中，n = 8;树突:0.047 平方微米，范围:0.024至0.166微米2，N = 11）。这是在一个类似的范围内前面所分析的端脑谷氨酸突触25。 在这两种刺和树突，金immunoparticles在个别突触AMPA-Rs的数目呈正突触区域相关（斯皮尔曼，棘:R = 0.88，树突:R = 0.60，P &lt;0.0001）（ 图6E）。相反，发现金immunoparticles为NMDA-Rs的数目在棘（斯皮尔曼，棘:R = 0.90，P &lt;0.002）与突触区域关联，但不是在树突性（r = 0.21，P = 0.29）（ 图6F ）。

Watch this Scientific Journal Video about Combined Optogenetic and Freeze-fracture Replica Immunolabeling to Examine Input-specific Arrangement of Glutamate Receptors in the Mouse Amygdala at JoVE.com

Combined Optogenetic and Freeze-fracture Replica Immunolabeling to Examine Input-specific Arrangement of Glutamate Receptors in the Mouse Amygdala

This article illustrates how the expression of neurotransmitter receptors can be quantified and the pattern analyzed at synapses with identified pre and postsynaptic elements using a combination of viral transduction of optogenetic tools and the freeze-fracture replica immunolabeling technique.

结合光遗传学和冷冻断裂免疫标记副本研究在老鼠杏仁核谷氨酸受体的特定投入安排

Freeze-fracture electron microscopy has been a major technique in ultrastructural research for over 40 years. However, the lack of effective means to ...

combined-optogenetic-freeze-fracture-replica-immunolabeling-to

Nanyang Technological University

Research

JoVE Journal

Neuroscience

10.9K 次观看.  Medical University of Innsbruck. This article illustrates how the expression of neurotransmitter receptors can be quantified and the pattern analyzed at synapses with identified pre and postsynaptic elements using a combination of viral transduction of optogenetic tools and the freeze-fracture replica immunolabeling technique.

视频: Combined Optogenetic and Freeze-fracture Replica Immunolabeling to Examine Input-specific Arrangement of Glutamate Receptors in the Mouse Amygdala

Fast Micro-iontophoresis of Glutamate and GABA: A Useful Tool to Investigate Synaptic Integration

One of the fundamental interests in neuroscience is to understand the integration of excitatory and inhibitory inputs along the very complex structure of the dendritic tree, which eventually leads to neuronal output of action potentials at the axon. The influence of diverse spatial and temporal parameters of specific synaptic input on neuronal output is currently under investigation, e.g. the distance-dependent attenuation of dendritic inputs, the location-dependent interaction of spatially segregated inputs, the influence of GABAergig inhibition on excitatory integration, linear and non-linear integration modes, and many more.
With fast micro-iontophoresis of glutamate and GABA it is possible to precisely investigate the spatial and temporal integration of glutamatergic excitation and GABAergic inhibition. Critical technical requirements are either a triggered fluorescent lamp, light-emitting diode (LED), or a two-photon scanning microscope to visualize dendritic branches without introducing significant photo-damage of the tissue. Furthermore, it is very important to have a micro-iontophoresis amplifier that allows for fast capacitance compensation of high resistance pipettes. Another crucial point is that no transmitter is involuntarily released by the pipette during the experiment.
Once established, this technique will give reliable and reproducible signals with a high neurotransmitter and location specificity. Compared to glutamate and GABA uncaging, fast iontophoresis allows using both transmitters at the same time but at very distant locations without limitation to the field of view. There are also advantages compared to focal electrical stimulation of axons: with micro-iontophoresis the location of the input site is definitely known and it is sure that only the neurotransmitter of interest is released. However it has to be considered that with micro-iontophoresis only the postsynapse is activated and presynaptic aspects of neurotransmitter release are not resolved. In this article we demonstrate how to set up micro-iontophoresis in brain slice experiments.

In this article we introduce fast micro-iontophoresis of neurotransmitters as a technique to investigate integration of postsynaptic signals with high spatial and temporal precision.

谷氨酸和GABA快速微离子导入:一个有用​​的工具，调查突触整合

One of the fundamental interests in neuroscience is to understand the integration of excitatory and inhibitory inputs along the very complex structure of ...

科研

神经科学

Use of pHluorin to Assess the Dynamics of Axon Guidance Receptors in Cell Culture and in the Chick Embryo

During development, axon guidance receptors play a crucial role in regulating axons sensitivity to both attractive and repulsive cues. Indeed, activation of the guidance receptors is the first step of the signaling mechanisms allowing axon tips, the growth cones, to respond to the ligands. As such, the modulation of their availability at the cell surface is one of the mechanisms that participate in setting the growth cone sensitivity. We describe here a method to precisely visualize the spatio-temporal cell surface dynamics of an axon guidance receptor both in vitro and in vivo in the developing chick spinal cord. We took advantage of the pH-dependent fluorescence property of a green fluorescent protein (GFP) variant to specifically detect the fraction of the axon guidance receptor that is addressed to the plasma membrane. We first describe the in vitro validation of such pH-dependent constructs and we further detail their use in vivo, in the chick spinal chord, to assess the spatio-temporal dynamics of the axon guidance receptor of interest.

We describe here the use of a pH-sensitive green fluorescent protein variant, pHluorin, to study the spatio-temporal dynamics of axon guidance receptors trafficking at the cell surface.&#160;The pHluorin-tagged receptor is expressed both in cell culture and in vivo, using electroporation of the chick embryo.

使用普洛林来评估阿克森指导受体在细胞培养和小鸡胚胎中的动力学

During development, axon guidance receptors play a crucial role in regulating axons sensitivity to both attractive and repulsive cues. Indeed, activation ...

Whole Mount Immunolabeling of Olfactory Receptor Neurons in the Drosophila Antenna

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

Whole Mount Immunolabeling of Olfactory Receptor Neurons in the Drosophila Antenna

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

嗅觉受体神经元在全山免疫标记<em&gt;果蝇</em&gt;天线

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

In vivo Optogenetic Stimulation of the Rodent Central Nervous System

The ability to probe defined neural circuits in awake, freely-moving animals with cell-type specificity, spatial precision, and high temporal resolution has been a long sought tool for neuroscientists in the systems-level search for the neural circuitry governing complex behavioral states. Optogenetics is a cutting-edge tool that is revolutionizing the field of neuroscience and represents one of the first systematic approaches to enable causal testing regarding the relation between neural signaling events and behavior. By combining optical and genetic approaches, neural signaling can be bi-directionally controlled through expression of light-sensitive ion channels (opsins) in mammalian cells. The current protocol describes delivery of specific wavelengths of light to opsin-expressing cells in deep brain structures of awake, freely-moving rodents for neural circuit modulation. Theoretical principles of light transmission as an experimental consideration are discussed in the context of performing in vivo optogenetic stimulation. The protocol details the design and construction of both simple and complex laser configurations and describes tethering strategies to permit simultaneous stimulation of multiple animals for high-throughput behavioral testing.

In vivo Optogenetic Stimulation of the Rodent Central Nervous System

Optogenetics has become a powerful tool for use in behavioral neuroscience experiments. This protocol offers a step-by-step guide to the design and set-up of laser systems, and provides a full protocol for carrying out multiple and simultaneous in vivo optogenetic stimulations compatible with most rodent behavioral testing paradigms.

在啮齿动物中枢神经系统的体内光遗传学刺激

The ability to probe defined neural circuits in awake, freely-moving animals with cell-type specificity, spatial precision, and high temporal resolution ...

Multi-photon Intracellular Sodium Imaging Combined with UV-mediated Focal Uncaging of Glutamate in CA1 Pyramidal Neurons

Multi-photon fluorescence microscopy has enabled the analysis of morphological and physiological parameters of brain cells in the intact tissue with high spatial and temporal resolution. Combined with electrophysiology, it is widely used to study activity-related calcium signals in small subcellular compartments such as dendrites and dendritic spines. In addition to calcium transients, synaptic activity also induces postsynaptic sodium signals, the properties of which are only marginally understood. Here, we describe a method for combined whole-cell patch-clamp and multi-photon sodium imaging in cellular micro domains of central neurons. Furthermore, we introduce a modified procedure for ultra-violet (UV)-light-induced uncaging of glutamate, which allows reliable and focal activation of glutamate receptors in the tissue. To this end, whole-cell recordings were performed on Cornu Ammonis subdivision 1 (CA1) pyramidal neurons in acute tissue slices of the mouse hippocampus. Neurons were filled with the sodium-sensitive fluorescent dye SBFI through the patch-pipette, and multi-photon excitation of SBFI enabled the visualization of dendrites and adjacent spines. To establish UV-induced focal uncaging, several parameters including light intensity, volume affected by the UV uncaging beam, positioning of the beam as well as concentration of the caged compound were tested and optimized. Our results show that local perfusion with caged glutamate (MNI-Glutamate) and its focal UV-uncaging result in inward currents and sodium transients in dendrites and spines. Time course and amplitude of both inward currents and sodium signals correlate with the duration of the uncaging pulse. Furthermore, our results show that intracellular sodium signals are blocked in the presence of blockers for ionotropic glutamate receptors, demonstrating that they are mediated by sodium influx though this pathway. In summary, our method provides a reliable tool for the investigation of intracellular sodium signals induced by focal receptor activation in intact brain tissue.

We describe the combination of focal UV-induced photo-activation of neuro-active compounds with whole-cell patch-clamp and multi-photon imaging of intracellular sodium transients in dendrites and spines of hippocampal neurons in acute tissue slices of the mouse brain.

多光子细胞内钠成像结合谷氨酸海马CA1锥体神经元的UV-介导的焦点解笼锁

Multi-photon fluorescence microscopy has enabled the analysis of morphological and physiological parameters of brain cells in the intact tissue with high ...

Optogenetic Stimulation of the Auditory Nerve

Direct electrical stimulation of spiral ganglion neurons (SGNs) by cochlear implants (CIs) enables open speech comprehension in the majority of implanted deaf subjects1-6. Nonetheless, sound coding with current CIs has poor frequency and intensity resolution due to broad current spread from each electrode contact activating a large number of SGNs along the tonotopic axis of the cochlea7-9. Optical stimulation is proposed as an alternative to electrical stimulation that promises spatially more confined activation of SGNs and, hence, higher frequency resolution of coding. In recent years, direct infrared illumination of&#160;the cochlea has been used to evoke responses in the auditory nerve10. Nevertheless it requires higher energies than electrical stimulation10,11 and uncertainty remains as to the underlying mechanism12. Here we describe a method based on optogenetics to stimulate SGNs with low intensity blue light, using transgenic mice with neuronal expression of channelrhodopsin 2 (ChR2)13 or virus-mediated expression of the ChR2-variant CatCh14. We used micro-light emitting diodes (&#181;LEDs) and fiber-coupled lasers to stimulate ChR2-expressing SGNs through a small artificial opening (cochleostomy) or the round window. We assayed the responses by scalp recordings of light-evoked potentials (optogenetic auditory brainstem response: oABR) or by microelectrode recordings from the auditory pathway and compared them with acoustic and electrical stimulation.

Cochlear implants (CIs) enable hearing by direct electrical stimulation of the auditory nerve. However, poor frequency and intensity resolution limits the quality of hearing with CIs. Here we describe optogenetic stimulation of the auditory nerve in mice as an alternative strategy for auditory research and developing future CIs.

听觉神经的光遗传学刺激

Direct electrical stimulation of spiral ganglion neurons (SGNs) by cochlear implants (CIs) enables open speech comprehension in the majority of implanted ...

Utilizing Combined Methodologies to Define the Role of Plasma Membrane Delivery During Axon Branching and Neuronal Morphogenesis

During neural development, growing axons extend to multiple synaptic partners by elaborating axonal branches. Axon branching is promoted by extracellular guidance cues like netrin-1 and results in dramatic increases to the surface area of the axonal plasma membrane. Netrin-1-dependent axon branching likely involves temporal and spatial control of plasma membrane expansion, the components of which are supplied through exocytic vesicle fusion. These fusion events are preceded by formation of SNARE complexes, comprising a v-SNARE, such as VAMP2 (vesicle-associated membrane protein 2), and plasma membrane t-SNAREs, syntaxin-1 and SNAP25 (synaptosomal-associated protein 25). Detailed herein isa multi-pronged approach used to examine the role of SNARE mediated exocytosis in axon branching. The strength of the combined approach is data acquisition at a range of spatial and temporal resolutions, spanning from the dynamics of single vesicle fusion events in individual neurons to SNARE complex formation and axon branching in populations of cultured neurons. This protocol takes advantage of established biochemical approaches to assay levels of endogenous SNARE complexes and Total Internal Reflection Fluorescence (TIRF) microscopy of cortical neurons expressing VAMP2 tagged with a pH-sensitive GFP (VAMP2-pHlourin) to identify netrin-1 dependent changes in exocytic activity in individual neurons. To elucidate the timing of netrin-1-dependent branching, time-lapse differential interference contrast (DIC) microscopy of single neurons over the order of hours is utilized. Fixed cell immunofluorescence paired with botulinum neurotoxins that cleave SNARE machinery and block exocytosis demonstrates that netrin-1 dependent axon branching requires SNARE-mediated exocytic activity.

Light microscopy techniques coupled with biochemical assays elucidate the involvement of SNARE-mediated exocytosis in netrin-dependent axon branching. This combination of techniques permits identification of molecular mechanisms controlling axon branching and cell shape change.

采用组合运用各种方法，定义质膜交付在轴突分支和神经元形态发生中的作用

During neural development, growing axons extend to multiple synaptic partners by elaborating axonal branches. Axon branching is promoted by extracellular ...

Using Enzyme-based Biosensors to Measure Tonic and Phasic Glutamate in Alzheimer's Mouse Models

Neurotransmitter disruption is often a key component of diseases of the central nervous system (CNS), playing a role in the pathology underlying Alzheimer's disease, Parkinson's disease, depression, and anxiety. Traditionally, microdialysis has been the most common (lauded) technique to examine neurotransmitter changes that occur in these disorders. But because microdialysis has the ability to measure slow 1-20 minute changes across large areas of tissue, it has the disadvantage of invasiveness, potentially destroying intrinsic connections within the brain and a slow sampling capability. A relatively newer technique, the microelectrode array (MEA), has numerous advantages for measuring specific neurotransmitter changes within discrete brain regions as they occur, making for a spatially and temporally precise approach. In addition, using MEAs is minimally invasive, allowing for measurement of neurotransmitter alterations in vivo. In our laboratory, we have been specifically interested in changes in the neurotransmitter, glutamate, related to Alzheimer's disease pathology. As such, the method described here has been used to assess potential hippocampal disruptions in glutamate in a transgenic mouse model of Alzheimer's disease. Briefly, the method used involves coating a multi-site microelectrode with an enzyme very selective for the neurotransmitter of interest and using self-referencing sites to subtract out background noise and interferents. After plating and calibration, the MEA can be constructed with a micropipette and lowered into the brain region of interest using a stereotaxic device. Here, the method described involves anesthetizing rTg(TauP301L)4510 mice and using a stereotaxic device to precisely target sub-regions (DG, CA1, and CA3) of the hippocampus.

Here, we describe the setup, software navigation, and data analysis for a spatially and temporally precise method of measuring tonic and phasic extracellular glutamate changes in vivo using enzyme-linked microelectrode arrays (MEA).

使用基于酶的生物传感器来衡量进补和阶段性谷氨酸在阿尔茨海默氏症小鼠模型

Neurotransmitter disruption is often a key component of diseases of the central nervous system (CNS), playing a role in the pathology underlying ...

A High-throughput Calcium-flux Assay to Study NMDA-receptors with Sensitivity to Glycine/D-serine and Glutamate

N-methyl-D-aspartate (NMDA) receptors (NMDAR) are classified as ionotropic glutamate receptors and have critical roles in learning and memory. NMDAR malfunction, expressed as either over- or under-activity caused by mutations, altered expression, trafficking, or localization, can contribute to numerous diseases, especially in the central nervous system. Therefore, understanding the receptor&#39;s biology as well as facilitating the discovery of compounds and small molecules is crucial in ongoing efforts to combat neurological diseases. Current approaches to studying the receptor have limitations including low throughput, high cost, and the inability to study its functional abilities due to the necessary presence of channel blockers to prevent NMDAR-mediated excitotoxicity. Additionally, the existing assay systems are sensitive to stimulation by glutamate only and lack sensitivity to stimulation by glycine, the other co-ligand of the NMDAR. Here, we present the first plate-based assay with high-throughput power to study an NMDA receptor with sensitivity to both co-ligands, glutamate and D-serine/glycine. This approach allows the study of different NMDAR subunit compositions and allows functional studies of the receptor in glycine- and/or glutamate-sensitive modes. Additionally, the method does not require the presence of inhibitors during measurements. The effects of positive and negative allosteric modulators can be detected with this assay and the known pharmacology of NMDAR has been replicated in our system. This technique overcomes the limitations of existing methods and is cost-effective. We believe that this novel technique will accelerate the discovery of therapies for NMDAR-mediated pathologies.

The goal of this protocol is to facilitate the study of NMDA-receptors (NMDAR) at a larger scale and allow the examination of modulatory effects of small molecules and their therapeutic applications.

高通量钙流量测定对甘氨酸/d-丝氨酸和谷氨酸敏感的 NMDA 受体的研究

N-methyl-D-aspartate (NMDA) receptors (NMDAR) are classified as ionotropic glutamate receptors and have critical roles in learning and memory. NMDAR ...

Muscle Velocity Recovery Cycles to Examine Muscle Membrane Properties

Although conventional nerve conduction studies (NCS) and electromyography (EMG) are suitable for the diagnosis of neuromuscular disorders, they provide limited information about muscle fiber membrane properties and underlying disease mechanisms. Muscle velocity recovery cycles (MVRCs) illustrate how the velocity of a muscle action potential depends on the time after a preceding action potential. MVRCs are closely related to changes in membrane potential that follow an action potential, thereby providing information about muscle fiber membrane properties. MVRCs may be recorded quickly and easily by direct stimulation and recording from multi-fiber bundles in vivo. MVRCs have been helpful in understanding disease mechanisms in several neuromuscular disorders. Studies in patients with channelopathies have demonstrated the different effects of specific ion channel mutations on muscle excitability. MVRCs have been previously tested in patients with neurogenic muscles. In this prior study, muscle relative refraction period (MRRP) was prolonged, and early supernormality (ESN) and late supernormality (LSN) were reduced in patients compared to healthy controls. Thereby, MVRCs can provide in vivo evidence of membrane depolarization in intact human muscle fibers that underlie their reduced excitability. The protocol presented here describes how to record MVRCs and analyze the recordings. MVRCs can serve as a fast, simple, and useful method for revealing disease mechanisms across a broad range of neuromuscular disorders.

Presented here is a protocol for the recording of muscle velocity recovery cycles (MVRCs), a new method of examining muscle membrane properties. MVRCs enable in vivo assessment of muscle membrane potential and alterations in muscle ion channel function in relation to pathology, and it enables the demonstration of muscle depolarization in neurogenic muscles.

肌肉速度恢复周期，检查肌肉膜属性

Although conventional nerve conduction studies (NCS) and electromyography (EMG) are suitable for the diagnosis of neuromuscular disorders, they provide ...