本研究由中国国家自然科学基金 (项目编号: 81373557; 81403327) 资助。

这项研究是由中国医学科学院伦理委员会 (参考编号 20160014) 批准的。所有程序都是按照国家卫生研究院关于实验室动物的护理和使用指南进行的 (国家科学院出版社, 华盛顿特区, 1996)。本研究采用四只成年雄性大鼠 (重量250-280 克)。所有动物都被安置在一个12小时的光/暗循环中, 控制着温度和湿度, 并允许免费获得食物和水。本研究中使用的仪器和材料显示在图 1中。 手术前, 所有仪器, 如立体定向框架和玻璃吸管, 都用70% 乙醇清洗。
1. 手术程序
<ol><li>使用立体定向地图集9 (图 2A) 确定 VPM 中感兴趣的坐标区域。</li>
	<li>准备一1µL 微型注射器, 配备玻璃微 (尖直径约10-20 µm) (图 1D), 并用液体石蜡进行测试。</li>
	<li>用腹腔注射麻醉7% 水合氯醛 (0.7 mL/100 g) 的大鼠。</li>
	<li>一旦深部麻醉证实与尾部捏和踏板撤退反射, 剃光头的动物的头部与电动剃刀和擦洗手术现场3倍, 10% 聚维酮碘其次70% 乙醇分别。</li>
	<li>把钝耳棒放到耳朵里, 把老鼠放到立体定向装置中, 把大鼠的上门牙放进嘴里 (图 1E), 然后在眼睛上涂抹眼膏。</li>
	<li>用70% 乙醇再次清洁手术部位的头部皮肤。使用无菌的外科手套和毛巾在不育条件下维持手术。</li>
	<li>用手术刀沿着矢状缝合 (图 1F) 在皮肤上作矢状切口。</li>
	<li>在整个手术过程中, 用无菌的棉尖喷头将肌肉和骨膜从头骨上刮掉, 以控制出血 (图 1F)。</li>
	<li>使用地图集的预定义坐标 (图 2A), 确定开颅手术 (图 1G) 的位置 (-3.3 毫米 Bregma 点, 2.6 毫米右至中线)。</li>
	<li>使用带有圆形尖端钻头 (#106) (图 1H) 的毛刺钻头进行开颅手术, 并在几分钟内继续钻至大约1毫米深度, 直至到达脑膜 (图 1I)。</li>
	<li>使用 microforceps 将硬脑膜置于注射部位, 使大脑皮层暴露 (图 1I)。</li>
	<li>用 10% BDA (1万分子量, 蒸馏水) 溶液 (图 1J) 改变微注射器中的液体石蜡。</li>
	<li>将注射器装入微注射装置并与微型泵连接 (图 1K)。 注: 注入量取决于微泵的速度。这里它被调整了到 30 nL/分钟 (图 1L)。</li>
	<li>在显微镜下, 将玻璃微与微注射装置手工插入 VPM, 通过大脑的皮质表面, 深度为5.8 毫米 (图 1M)。</li>
	<li>压力-注入 100 nL 10% BDA 进入 VPM 在3分钟 (35 nL/分钟) 与微型泵 (图 1L, M)。</li>
	<li>注射后, 把吸管放在原地, 再加5分钟, 然后慢慢地取出。</li>
	<li>用无菌螺纹缝合伤口 (图 1N)。遵循当地的动物护理委员会的指导方针, 为手术前和术后镇痛。</li>
	<li>把老鼠放在温暖的恢复区, 直到它苏醒并完全恢复。</li>
	<li>把恢复的老鼠送回笼子里去。</li>
</ol>2. 显影和章节
<ol><li>经过典型的10天的生存时间, 注射的动物与过量的10% 氨基甲酸乙酯 (2 mL/100 g) 的腹腔注射, 以诱导安乐死。</li>
	<li>灌注实验鼠的引擎盖 (图 1O)。<ol>
<li>一旦呼吸停止, 使用剪刀和镊子, 打开大鼠胸腔进入心脏。将静脉导管插入左心室向主动脉, 然后打开右耳廓。</li>
		<li>首先灌注与0.9% 磷酸盐缓冲盐水 (PBS) 在生理温度 (37 °c) 大约1-2 分钟直到血液从心脏撤出是清楚的, 然后继续与250-300 毫升4% 多聚甲醛在 0.1 M 磷酸盐缓冲 (PB, pH 7.4)。</li>
	</ol>
</li>
	<li>灌注后, 切开头部皮肤, 打开头骨, 然后解剖大鼠大脑。后修复解剖的大脑在4% 多聚甲醛2小时室温 (26 °c), 然后 cryoprotect 30% 蔗糖在0.1 米 PBS (pH 7.4) 3 天4摄氏度, 直到大脑沉浸在解决方案(图 1P)。</li>
	<li>一旦大脑沉浸在溶液中, 将大脑分成三个块, 在大脑矩阵的日冕方向上 (图 1Q)。中心块包含 VPM 和 S1。</li>
	<li>在40µm 上, 在一个冰冻阶段的切片系统中, 将大脑的中心块切开到日冕方向。用0.1 米 PBS (pH 7.4) (图 1RS) 在6井盘中有序地收集这些部分。</li>
</ol>3. 标准 ABC 染色
注意: 从大脑的每第三个日冕部分自由浮动部分用于可视化 BDA 标签与标准 ABC 过程10。
<ol><li>将0.1 米 PBS 中的剖面冲洗约1分钟。</li>
	<li>将 1% ABC 溶液中的剖面孵育为0.1 米 PB (pH 7.4), 在室温下含有0.3% 海卫 X-100 1 小时。</li>
	<li>在50毫米的三个缓冲 (pH 7.4) 洗涤部分三次。</li>
	<li>将包含 0.02% 33 '-diaminobenzidine tetrahydrochloride (民建) 和 0.01% H2O2的解决方案中的各部分着色为50毫米, 在室温下约为2-5 分钟。</li>
	<li>在50毫米的三个缓冲 (pH 7.4) 洗涤部分三次。</li>
	<li>使用标准的组织化学技术 (图 1T) 将切片安装在显微镜幻灯片上; 请参阅补充视频文件 III、灌注和切片)。</li>
	<li>在室温下, 将空气中的部分干燥一夜。</li>
	<li>在一系列酒精 (50%、70%、95%、100%) 溶液中简要地脱水切片。将每个解决方案中的幻灯片淹没大约十五年代。不要让幻灯片在每个步骤之间晾干。</li>
	<li>将二甲苯中的剖面清除三次, 约20分钟。</li>
	<li>将2或3滴苦瓜放在切片上, 然后将盖玻片放在各部分。</li>
</ol>4. 双荧光染色对 BDA 和大脑皮层的基本神经元
注: 对比中, 采用双荧光染色法观察了 streptavidin-AF594 和复染与荧光尼斯尔染色 AF500/525 在邻段中的 BDA 标记和基本神经元的相关性。
<ol><li>将0.1 米 PBS 中的剖面冲洗约1分钟。</li>
	<li>streptavidin-AF594 (1:500) 和 AF500/525 绿色荧光尼斯尔染色 (1:1, 000) 在0.1 米 PBS (pH 7.4) 的混合溶液中孵化剖面, 在室温下含有0.3% 的海卫 X-100 2 小时。</li>
	<li>用0.1 米 PB (pH 7.4) 冲洗三次。</li>
	<li>使用标准的组织化学技术将切片安装在显微镜幻灯片上。将空气中的部分干燥约1小时。</li>
	<li>观察前将盖玻片应用于蒸馏水中50% 甘油的荧光切片。</li>
</ol>5. 双荧光染色对中间神经元和脑皮质的促进
注: 采用双荧光染色法观察中间神经元与 streptavidin-AF594、光伏免疫化学在皮质靶区代表性切片上的相关性。
<ol><li>冲洗0.1 米 PBS (pH 7.4) 的代表性部分约1分钟。</li>
	<li>在包含3% 正常山羊血清和0.3% 海卫 X-100 0.1 米 PBS 的阻塞溶液中孵化部分30分钟。</li>
	<li>将这些部分转移到一个小鼠单克隆抗 PV IgG (1:1, 000) 的解决方案, 0.1 米 PBS (pH 7.4) 包含1% 正常山羊血清和0.3% 海卫 X-100 为隔夜在4°c。</li>
	<li>第二天, 在0.1 米 PBS (pH 7.4) 上冲洗三次。</li>
	<li>在2米 PBS (pH 1:40,000) 中, anti-mouse-AF488 山羊的二次抗体 (1:500)、streptavidin-AF594 (1:500) 和 4 '、6-diamidino-0.1-苯基吲哚盐酸盐 (DAPI、7.4) 的混合溶液, 包括1% 条正常山羊血清和0.3% 海卫。X-100 1 小时。</li>
	<li>重复步骤4.3 到4.5。</li>
</ol>6. 观察
<ol><li>拍摄 VPM、丘脑-皮质轴突和 corticothalamic 神经元的图像。<ol>
<li>观察荧光样品与共焦成像系统装备目标透镜 (4x, na: 0.13; 10x, na: 0.40; 和 40x, na: 0.95)。使用激发和发射波长 405 (蓝色), 488 (绿色) 和 559 (红色) nm。 注: 在这里, 共焦针孔是152µm (4x, 10x) 和105µm (40x)。图像捕获的空间分辨率为 1024 x 1024 像素 (4x、10x) 和 640 x 640 像素 (40x)。</li>
		<li>在2µm 的连续帧中拍摄二十幅图像, 每节的厚度为40µm (Z 系列)。</li>
		<li>将图像与共焦图像处理软件系统集成到一个单一的聚焦图像中, 进行三维分析, 如下所示: 设置起始焦平面→设置端部焦平面→设置步长→选择深度图案→图像捕获→ Z 系列。</li>
	</ol>
</li>
	<li>用装有数码相机的光镜拍摄 brightfield 图像 (4x, na: 0.13; 10x, na: 0.40; 40x, na: 0.95 透镜)。使用500毫秒的曝光时间. 使用照片编辑软件调整图像的亮度和对比度, 并添加标签。</li>
</ol>

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作者没有什么可透露的。

选择合适的示踪剂是成功的神经追踪实验的关键步骤。在 bda 家族中, 建议通过顺神经通路优先输送高分子量的 bda (1万分子量), 与低分子量 bda (3000 分子量)2,3,11,12,13. 然而, 许多研究还表明, 高分子量的 BDA 也可能会与顺追踪1,2,</...

高分子量 BDA (1万分子量), 一种高度灵敏的示踪剂, 已用于在中枢神经系统中追踪神经通路20年以上的1。虽然 bda 的使用是一种常见的神经道追踪技术, 但在动物中, bda 标签的质量可能受到各种因素的影响, 如1,2,3。最近的研究表明, BDA 标签的优化结构不仅与适当的注射后生存时间有关, 而且与染色方法4相关。到目前为止, 传统的亲和-生物素-过氧化物酶复合物 (ABC), 链亲和素异硫氰酸酯, 和 streptavidin-AF594 染色方法, 以揭示 BDA 标签在以前的研究2, 3, 4,5。相比之下, BDA 的荧光染色可以很容易地进行。
为了推广高分子量 BDA 的应用, 本研究引入了一种精细化的协议。在将 bda 注射液注入大鼠脑丘脑的 VPM 后, 采用常规 ABC 染色法和双荧光染色技术对 bda 标签进行了分析, 观察了 bda 标签的相关性和基本streptavidin-AF594 和荧光尼斯尔组织化学或 PV 免疫化学的皮质靶上的神经元素或中间神经元。通过 VPM 与原发性体感皮层 (S1)6、7、8之间的相互神经通路, 我们集中观察了在丘脑-皮质预测轴突和 corticothalamic 中的 BDA 标记。投射的细胞 somas 在 S1。通过这一过程, 我们希望不仅提供一个详细的协议, 以获得高品质的神经标记的高分子量 bda, 而且还有一个完善的协议, 结合荧光 BDA 标签和其他荧光神经标记与组织化学或免疫化学。这种方法在共聚焦激光扫描显微镜下研究局部神经回路及其化学特性是比较可取的。

<table>
	<tbody>
		<tr>
			<td>Biotinylated dextran amine (BDA)</td>
			<td>Molecular Probes</td>
			<td>D1956</td>
			<td>10,000 molecular weight</td>
		</tr>
		<tr>
			<td>Streptavidin-Alexa Fluor 594</td>
			<td>Molecular Probes</td>
			<td>S32356</td>
			<td>Protect from light</td>
		</tr>
		<tr>
			<td>500/525 green fluorescent Nissl stain</td>
			<td>Molecular Probes</td>
			<td>N21480</td>
			<td>Protect from light</td>
		</tr>
		<tr>
			<td>Brain stereotaxis instrument</td>
			<td>Narishige</td>
			<td>SR-50</td>
			<td></td>
		</tr>
		<tr>
			<td>Freezing microtome</td>
			<td>Thermo</td>
			<td>Microm International GmbH</td>
			<td></td>
		</tr>
		<tr>
			<td>Confocal imaging</td>
			<td>Olympus</td>
			<td>FV1200</td>
			<td></td>
		</tr>
		<tr>
			<td>system</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Micro Drill</td>
			<td>Saeyang Microtech</td>
			<td>Marathon-N7</td>
			<td></td>
		</tr>
		<tr>
			<td>Sprague Dawley</td>
			<td>Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences</td>
			<td>SCKX (JUN) 2012-004</td>
			<td></td>
		</tr>
		<tr>
			<td>Vectastain ABC Kit</td>
			<td>Vector Laboratories</td>
			<td>PK-4000</td>
			<td></td>
		</tr>
		<tr>
			<td>superfrost plus microscope slides</td>
			<td>Thermo</td>
			<td>#4951PLUS-001</td>
			<td>25x75x1mm</td>
		</tr>
		<tr>
			<td>Photoshop and Illustration</td>
			<td>Adobe</td>
			<td>CS5</td>
			<td></td>
		</tr>
	</tbody>
</table>

improving the application of high molecular weight biotinylated dextran amine for thalamocortical projection tracing in the rat

高分子量生物素化葡聚糖胺 (BDA) 已被用作高度敏感的神经解剖学示踪剂数十年。由于其标签的质量受到各种因素的影响, 在这里, 我们提供了一个完善的协议, 以应用高分子量的 BDA 研究最佳神经标记在中枢神经系统。经立体定向注入内侧核 (VPM) 的大鼠丘脑通过一个微妙的玻璃吸管, bda 染色的荧光链亲和素 Alexa (AF) 594 和复染荧光尼斯尔染色 AF500/525。在绿色尼斯尔染色的背景下, 在体感皮层显示了红色的 BDA 标记, 包括神经元细胞体和轴突末端。此外, 对 bda 和钙结合蛋白 parvalbumin (pv) 进行了双荧光染色, 观察了 bda 标记与中间神经元在皮质靶上的相关性, 为研究局部神经电路及其化学特性。因此, 这种精制方法不仅适用于通过丘脑和大脑皮层之间的相互神经通路对高品质的神经标记进行可视化, 而且还可以同时证明其他具有荧光组织化学或免疫化学的神经标记。

10天后, BDA 注入 VPM 的生存是足够的, 以产生强烈的神经标记, 在相应的皮质区域与注射方 (图 2)。BDA 的常规 ABC 和荧光染色程序都揭示了 S1 上类似的神经标记模式, 包括 anterogradely 标记的丘脑-皮质轴突和 retrogradely 标记 corticothalamic 神经元(图 2C, D).
对于 anterogradely 标记的...

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Improving the Application of High Molecular Weight Biotinylated Dextran Amine for Thalamocortical Projection Tracing in the Rat

在这里, 我们提出了一个完善的协议, 以有效地揭示生物素化葡聚糖胺 (BDA) 标签的荧光染色方法通过一个相互的神经通路。它适用于分析 BDA 标签的精细结构, 并在共焦激光扫描显微镜下将其与其他神经元进行区分。

高分子量生物素化葡聚糖胺在大鼠丘脑-皮质投影示踪中的应用

High molecular weight biotinylated dextran amine (BDA) has been used as a highly sensitive neuroanatomical tracer for many decades. Since the quality of ...

improving-application-high-molecular-weight-biotinylated-dextran

Research

JoVE Journal

Neuroscience

8.9K 次观看.  China Academy of Chinese Medical Sciences. 在这里, 我们提出了一个完善的协议, 以有效地揭示生物素化葡聚糖胺 (BDA) 标签的荧光染色方法通过一个相互的神经通路。它适用于分析 BDA 标签的精细结构, 并在共焦激光扫描显微镜下将其与其他神经元进行区分。

视频: Improving the Application of High Molecular Weight Biotinylated Dextran Amine for Thalamocortical Projection Tracing in the Rat

Progressive-ratio Responding for Palatable High-fat and High-sugar Food in Mice

Foods that are rich in fat and sugar significantly contribute to over-eating and escalating rates of obesity. The consumption of palatable foods can produce a rewarding effect that strengthens action-outcome associations and reinforces future behavior directed at obtaining these foods. Increasing evidence that the rewarding effects of energy-dense foods play a profound role in overeating and the development of obesity has heightened interest in studying the genes, molecules and neural circuitry that modulate food reward1,2. The rewarding impact of different stimuli can be studied by measuring the willingness to work to obtain them, such as in operant conditioning tasks3. Operant models of food reward measure acquired and voluntary behavioral responses that are directed at obtaining food. A commonly used measure of reward strength is an operant procedure known as the progressive ratio (PR) schedule of reinforcement.4,5 In the PR task, the subject is required to make an increasing number of operant responses for each successive reward. The pioneering study of Hodos (1961) demonstrated that the number of responses made to obtain the last reward, termed the breakpoint, serves as an index of reward strength4. While operant procedures that measure changes in response rate alone cannot separate changes in reward strength from alterations in performance capacity, the breakpoint derived from the PR schedule is a well-validated measure of the rewarding effects of food. The PR task has been used extensively to assess the rewarding impact of drugs of abuse and food in rats (e.g.,6-8), but to a lesser extent in mice9. The increased use of genetically engineered mice and diet-induced obese mouse models has heightened demands for behavioral measures of food reward in mice. In the present article we detail the materials and procedures used to train mice to respond (lever-press) for a high-fat and high-sugar food pellets on a PR schedule of reinforcement. We show that breakpoint response thresholds increase following acute food deprivation and decrease with peripheral administration of the anorectic hormone leptin and thereby validate the use of this food-operant paradigm in mice.

The present report details the protocol employed to measure the rewarding effects of high-fat food in mice using a progressive ratio operant conditioning task.

累进比率响应小鼠可口的高脂肪和高糖食品

Foods that are rich in fat and sugar significantly contribute to over-eating and escalating rates of obesity. The consumption of palatable foods can ...

科研

神经科学

Visualization of Proprioceptors in Drosophila Larvae and Pupae

Proprioception is the ability to sense the motion, or position, of body parts by responding to stimuli arising within the body. In fruitflies and other insects proprioception is provided by specialized sensory organs termed chordotonal organs (ChOs) 2. Like many other organs in Drosophila, ChOs develop twice during the life cycle of the fly. First, the larval ChOs develop during embryogenesis. Then, the adult ChOs start to develop in the larval imaginal discs and continue to differentiate during metamorphosis.
The development of larval ChOs during embryogenesis has been studied extensively 10,11,13,15,16. The centerpiece of each ChO is a sensory unit composed of a neuron and a scolopale cell. The sensory unit is stretched between two types of accessory cells that attach to the cuticle via specialized epidermal attachment cells 1,9,14. When a fly larva moves, the relative displacement of the epidermal attachment cells leads to stretching of the sensory unit and consequent opening of specific transient receptor potential vanilloid (TRPV) channels at the outer segment of the dendrite 8,12. The elicited signal is then transferred to the locomotor central pattern generator circuit in the central nervous system.
Multiple ChOs have been described in the adult fly 7. These are located near the joints of the adult fly appendages (legs, wings and halters) and in the thorax and abdomen. In addition, several hundreds of ChOs collectively form the Johnston's organ in the adult antenna that transduce acoustic to mechanical energy 3,5,17,4.
In contrast to the extensive knowledge about the development of ChOs in embryonic stages, very little is known about the morphology of these organs during larval stages. Moreover, with the exception of femoral ChOs 18 and Johnston's organ, our knowledge about the development and structure of ChOs in the adult fly is very fragmentary.
Here we describe a method for staining and visualizing ChOs in third instar larvae and pupae. This method can be applied together with genetic tools to better characterize the morphology and understand the development of the various ChOs in the fly.

Visualization of Proprioceptors in Drosophila Larvae and Pupae

A method to immunostain and visualize chordotonal organs in larvae and pupae of Drosophila melanogaster is described.

可视化本体感受器<em&gt;果蝇</em&gt;幼虫和蛹

Proprioception is the ability to sense the motion, or position, of body parts by responding to stimuli arising within the body. In fruitflies and other ...

Transsynaptic Tracing from Peripheral Targets with Pseudorabies Virus Followed by Cholera Toxin and Biotinylated Dextran Amines Double Labeling

Transsynaptic tracing has become a powerful tool used to analyze central efferents that regulate peripheral targets through multi-synaptic circuits. This approach has been most extensively used in the brain by utilizing the swine pathogen pseudorabies virus (PRV)1. PRV does not infect great apes, including humans, so it is most commonly used in studies on small mammals, especially rodents. The pseudorabies strain PRV152 expresses the enhanced green fluorescent protein (eGFP) reporter gene and only crosses functional synapses retrogradely through the hierarchical sequence of synaptic connections away from the infection site2,3. Other PRV strains have distinct microbiological properties and may be transported in both directions (PRV-Becker and PRV-Kaplan)4,5&#160;.&#160;This protocol will deal exclusively with PRV152. By delivering the virus at a peripheral site, such as muscle, it is possible to limit the entry of the virus into the brain through a specific set of neurons. The resulting pattern of eGFP signal throughout the brain then resolves the neurons that are connected to the initially infected cells. As the distributed nature of transsynaptic tracing with pseudorabies virus makes interpreting specific connections within an identified network difficult, we present a sensitive and reliable method employing biotinylated dextran amines (BDA) and cholera toxin subunit b (CTb) for confirming the connections between cells identified using PRV152. Immunochemical detection of BDA and CTb with peroxidase and DAB (3, 3&#39;-diaminobenzidine) was chosen because they are effective at revealing cellular processes including distal dendrites6-11.

Transsynaptic tracing has become a powerful tool for analyzing central efferents regulating peripheral targets through multi-synaptic circuits. Here we present a protocol that exploits the transsynaptic pseudorabies virus to identify and localize a functional brain circuit, followed by classical tract tracing techniques to validate specific connections in the circuit between identified groups of neurons.

从外围目标跨突触跟踪与伪狂犬病病毒其次是霍乱毒素和生物素葡聚糖胺双标

Transsynaptic tracing has become a powerful tool used to analyze central efferents that regulate peripheral targets through multi-synaptic circuits. This ...

Design and Fabrication of Ultralight Weight, Adjustable Multi-electrode Probes for Electrophysiological Recordings in Mice

The number of physiological investigations in the mouse, mus musculus, has experienced a recent surge, paralleling the growth in methods of genetic targeting for microcircuit dissection and disease modeling. The introduction of optogenetics, for example, has allowed for bidirectional manipulation of genetically-identified neurons, at an unprecedented temporal resolution. To capitalize on these tools and gain insight into dynamic interactions among brain microcircuits, it is essential that one has the ability to record from ensembles of neurons deep within the brain of this small rodent, in both head-fixed and freely behaving preparations. To record from deep structures and distinct cell layers requires a preparation that allows precise advancement of electrodes towards desired brain regions. To record neural ensembles, it is necessary that each electrode be independently movable, allowing the experimenter to resolve individual cells while leaving neighboring electrodes undisturbed. To do both in a freely behaving mouse requires an electrode drive that is lightweight, resilient, and highly customizable for targeting specific brain structures.
A technique for designing and fabricating miniature, ultralight weight, microdrive electrode arrays that are individually customizable and easily assembled from commercially available parts is presented. These devices are easily scalable and can be customized to the structure being targeted; it has been used successfully to record from thalamic and cortical regions in a freely behaving animal during natural behavior.

Understanding the neural substrates of behavior requires brain circuit ensemble recording. Because of its genetic tractability, the mouse offers a model for circuit dissection and disease mimicry. Here, a method of designing and fabricating miniaturized probes is described that is suitable for targeting deep brain structure in the mouse.

设计和超轻重量的制作，可调节的多电极电生理记录小鼠探头

The number of physiological investigations in the mouse, mus musculus, has experienced a recent surge, paralleling the growth in methods of genetic ...

Conditional Genetic Transsynaptic Tracing in the Embryonic Mouse Brain

Anatomical path tracing is of pivotal importance to decipher the relationship between brain and behavior. Unraveling the formation of neural circuits during embryonic maturation of the brain however is technically challenging because most transsynaptic tracing methods developed to date depend on stereotaxic tracer injection. To overcome this problem, we developed a binary genetic strategy for conditional genetic transsynaptic tracing in the mouse brain. Towards this end we generated two complementary knock-in mouse strains to selectively express the bidirectional transsynaptic tracer barley lectin (BL) and the retrograde transsynaptic tracer Tetanus Toxin fragment C from the ROSA26 locus after Cre-mediated recombination. Cell-specific tracer production in these mice is genetically encoded and does not depend on mechanical tracer injection. Therefore our experimental approach is suitable to study neural circuit formation in the embryonic murine brain. Furthermore, because tracer transfer across synapses depends on synaptic activity, these mouse strains can be used to analyze the communication between genetically defined neuronal populations during brain development at a single cell resolution. Here we provide a detailed protocol for transsynaptic tracing in mouse embryos using the novel recombinant ROSA26 alleles. We have utilized this experimental technique in order to delineate the neural circuitry underlying maturation of the reproductive axis in the developing female mouse brain.

Capitalizing on a binary genetic strategy we provide a detailed protocol for neural circuit tracing in mice that express complementary transsynaptic tracers after Cre-mediated recombination. Because cell-specific tracer production is genetically encoded, our experimental approach is suitable to study the formation and maturation of neural circuitry during murine embryonic brain development at a single cell resolution.

有条件的遗传跨突触标记在胚胎小鼠脑

Anatomical path tracing is of pivotal importance to decipher the relationship between brain and behavior. Unraveling the formation of neural circuits ...

A Simple One-step Dissection Protocol for Whole-mount Preparation of Adult Drosophila Brains

There is an increasing interest in using Drosophila to model human brain degenerative diseases, map neuronal circuitries in adult brains, and study the molecular and cellular basis of higher brain functions. A whole-mount preparation of adult brains with well-preserved morphology is critical for such whole brain-based studies, but can be technically challenging and time-consuming. This protocol describes an easy-to-learn, one-step dissection approach of an adult fly head in less than 10 s, while keeping the intact brain attached to the rest of the body to facilitate subsequent processing steps. The procedure helps remove most of the eye and tracheal tissues normally associated with the brain that can interfere with the later imaging step, and also places less demand on the quality of the dissecting forceps. Additionally, we describe a simple method that allows convenient flipping of the mounted brain samples on a coverslip, which is important for imaging both sides of the brains with similar signal intensity and quality. As an example of the protocol, we present an analysis of dopaminergic (DA) neurons in adult brains of WT (w1118) flies. The high efficacy of the dissection method makes it particularly useful for large-scale adult brain-based studies in Drosophila.

A Simple One-step Dissection Protocol for Whole-mount Preparation of Adult Drosophila Brains

The adult Drosophila brain is a valuable system for studying neuronal circuitry, higher brain functions, and complex disorders. An efficient method to dissect whole brain tissue from the small fly head will facilitate brain-based studies. Here we describe a simple, one-step dissection protocol of adult brains with well-preserved morphology.

一个简单的一步解剖协议成人全安装准备<em&gt;果蝇</em&gt;脑

There is an increasing interest in using Drosophila to model human brain degenerative diseases, map neuronal circuitries in adult brains, and study the ...

Sublimation of DAN Matrix for the Detection and Visualization of Gangliosides in Rat Brain Tissue for MALDI Imaging Mass Spectrometry

Sample preparation is key for optimal detection and visualization of analytes in Matrix-assisted Laser Desorption/Ionization (MALDI) Imaging Mass Spectrometry (IMS) experiments. Determining the appropriate protocol to follow throughout the sample preparation process can be difficult as each step must be optimized to comply with the unique characteristics of the analytes of interest. This process involves not only finding a compatible matrix that can desorb and ionize the molecules of interest efficiently, but also selecting the appropriate matrix deposition technique. For example, a wet matrix deposition technique, which entails dissolving a matrix in solvent, is superior for desorption of most proteins and peptides, whereas dry matrix deposition techniques are particularly effective for ionization of lipids. Sublimation has been reported as a highly efficient method of dry matrix deposition for the detection of lipids in tissue by MALDI IMS due to the homogeneity of matrix crystal deposition and minimal analyte delocalization as compared to many wet deposition methods 1,2. Broadly, it involves placing a sample and powdered matrix in a vacuum-sealed chamber with the samples pressed against a cold surface. The apparatus is then lowered into a heated bath (sand or oil), resulting in sublimation of the powdered matrix onto the cooled tissue sample surface. Here we describe a sublimation protocol using 1,5-diaminonaphthalene (DAN) matrix for the detection and visualization of gangliosides in the rat brain using MALDI IMS.

A protocol for the sublimation of DAN matrix onto rat brain tissue for the detection of gangliosides using MALDI Imaging Mass Spectrometry is presented.

DAN矩阵升华为神经节苷脂对大鼠脑组织的检测和可视化MALDI成像质谱

Sample preparation is key for optimal detection and visualization of analytes in Matrix-assisted Laser Desorption/Ionization (MALDI) Imaging Mass ...

Simultaneous Evaluation of Cerebral Hemodynamics and Light Scattering Properties of the In Vivo Rat Brain Using Multispectral Diffuse Reflectance Imaging

The simultaneous evaluation of cerebral hemodynamics and the light scattering properties of in vivo rat brain tissue is demonstrated using a conventional multispectral diffuse reflectance imaging system. This system is constructed from a broadband white light source, a motorized filter wheel with a set of narrowband interference filters, a light guide, a collecting lens, a video zoom lens, and a monochromatic charged-coupled device (CCD) camera. An ellipsoidal cranial window is made in the skull bone of a rat under isoflurane anesthesia to capture in vivo multispectral diffuse reflectance images of the cortical surface. Regulation of the fraction of inspired oxygen using a gas mixture device enables the induction of different respiratory states such as normoxia, hyperoxia, and anoxia. A Monte Carlo simulation-based multiple regression analysis for the measured multispectral diffuse reflectance images at nine wavelengths (500, 520, 540, 560, 570, 580, 600, 730, and 760 nm) is then performed to visualize the two-dimensional maps of hemodynamics and the light scattering properties of the in vivo rat brain.

Simultaneous Evaluation of Cerebral Hemodynamics and Light Scattering Properties of the In Vivo Rat Brain Using Multispectral Diffuse Reflectance Imaging

The simultaneous evaluation of cerebral hemodynamics and the light scattering properties of in vivo rat brain tissue is demonstrated using a conventional multispectral diffuse reflectance imaging system.

脑血流动力学和的光散射特性的同步评估<em&gt;体内</em&gt;大鼠脑使用多光谱漫反射成像

The simultaneous evaluation of cerebral hemodynamics and the light scattering properties of in vivo rat brain tissue is demonstrated using a conventional ...

Visualization of the Axonal Projection Pattern of Embryonic Motor Neurons in Drosophila

The establishment of functional neuromuscular circuits relies on precise connections between developing motor axons and target muscles. Motor neurons extend growth cones to navigate along specific pathways by responding to a large number of axon guidance cues that emanate from the surrounding extracellular environment. Growth cone target recognition also plays a critical role in neuromuscular specificity. This work presents a standard immunohistochemistry protocol to visualize motor neuron projections of late stage-16 Drosophila melanogaster embryos. This protocol includes a few key steps, including a genotyping procedure, to sort the desired mutant embryos; an immunostaining procedure, to tag embryos with fasciclin II (FasII) antibody; and a dissection procedure, to generate filleted preparations from fixed embryos. Motor axon projections and muscle patterns in the periphery are much better visualized in flat preparations of filleted embryos than in whole-mount embryos. Therefore, the filleted preparation of fixed embryos stained with FasII antibody provides a powerful tool to characterize the genes required for motor axon pathfinding and target recognition, and it can also be applied to both loss-of-function and gain-of-function genetic screens.

Visualization of the Axonal Projection Pattern of Embryonic Motor Neurons in Drosophila

This work details a standard immunohistochemistry method to visualize motor neuron projections of late stage-16 Drosophila melanogaster embryos. The filleted preparation of fixed embryos stained with FasII antibody provides a powerful tool to characterize the genes required for motor axon pathfinding and target recognition during neural development.

胚胎运动神经元轴突投影模式的可视化<em&gt;果蝇</em

The establishment of functional neuromuscular circuits relies on precise connections between developing motor axons and target muscles. Motor neurons ...

High-throughput Analysis of Locomotor Behavior in the Drosophila Island Assay

Advances in next-generation sequencing technologies contribute to the identification of (candidate) disease genes for movement disorders and other neurological diseases at an increasing speed. However, little is known about the molecular mechanisms that underlie these disorders. The genetic, molecular, and behavioral toolbox of Drosophila melanogaster makes this model organism particularly useful to characterize new disease genes and mechanisms in a high-throughput manner. Nevertheless, high-throughput screens require efficient and reliable assays that, ideally, are cost-effective and allow for the automatized quantification of traits relevant to these disorders. The island assay is a cost-effective and easily set-up method to evaluate Drosophila locomotor behavior. In this assay, flies are thrown onto a platform from a fixed height. This induces an innate motor response that enables the flies to escape from the platform within seconds. At present, quantitative analyses of filmed island assays are done manually, which is a laborious undertaking, particularly when performing large screens.
This manuscript describes the &#34;Drosophila Island Assay&#34; and &#34;Island Assay Analysis&#34; algorithms for&#160;high-throughput, automated data processing and quantification of island assay data. In the setup, a simple webcam connected to a laptop collects an image series of the platform while the assay is performed. The &#34;Drosophila Island Assay&#34; algorithm developed for the open-source software Fiji processes these image series and quantifies, for each experimental condition, the number of flies on the platform over time. The &#34;Island Assay Analysis&#34; script, compatible with the free software R, was developed to automatically process the obtained data and to calculate whether treatments/genotypes are statistically different. This greatly improves the efficiency of the island assay and makes it a powerful readout for basic locomotion and flight behavior. It can thus be applied to large screens investigating fly locomotor ability, Drosophila models of movement disorders, and drug efficacy.

High-throughput Analysis of Locomotor Behavior in the Drosophila Island Assay

The island assay is a relatively new, cost-effective assay that can be used to evaluate the basic locomotor behavior of Drosophila melanogaster. This manuscript describes algorithms for automatic data processing and objective quantification of island assay data, making this assay a sensitive, high-throughput readout for large genetic or pharmacological screens.