Here, we describe a physiological approach that allows identification and in-depth analysis of a defined population of sensory neurons in acute coronal tissue slices of the mouse vomeronasal organ using whole-cell patch-clamp recordings.
In most mammals, the vomeronasal organ (VNO) is a chemosensory structure that detects both hetero- and conspecific social cues. Vomeronasal sensory neurons (VSNs) express a specific type of G protein-coupled receptor (GPCR) from at least three different chemoreceptor gene families allowing sensitive and specific detection of chemosensory cues. These families comprise the V1r and V2r gene families as well as the formyl peptide receptor (FPR)-related sequence (Fpr-rs) family of putative chemoreceptor genes. In order to understand the physiology of vomeronasal receptor-ligand interactions and downstream signaling, it is essential to identify the biophysical properties inherent to each specific class of VSNs.
The physiological approach described here allows identification and in-depth analysis of a defined population of sensory neurons using a transgenic mouse line (Fpr-rs3-i-Venus). The use of this protocol, however, is not restricted to this specific line and thus can easily be extended to other genetically modified lines or wild type animals.
大多数动物在很大程度上依赖于它们的化学感官与周围环境相互作用。嗅觉效力于寻找和评估的食物,躲避捕食者和定位合适的交配伙伴的重要作用。在大多数哺乳动物,嗅觉系统包括至少四个解剖学和功能上不同的外周子系统组成:主嗅觉上皮1,2,所述Grueneberg神经节3,4,马塞拉5,6的间隔器官和犁鼻器。该VNO包括配件嗅觉系统(AOS),它在检测传达的身份,性别,社会地位和性状态7-10信息化学信号主要作用的外周感觉结构。所述VNO位于鼻中隔右腭以上的基。在小鼠实验中,它是一个双边盲结束管封闭在一个软骨胶囊11-13。该机构由两部分组成的月牙形内侧感觉上皮的lium该怀有VSNS和侧面的非感觉部分。两个上皮之间在于,其经由窄犁鼻管14连接至鼻 腔粘液填充管腔。在非感觉组织的有大的横向血管提供了一种血管泵送机构,以促进通过负压15,16相对较大,大多非易失性分子如肽或小蛋白质到VNO管腔的进入。该VNO的结构部件是在出生和器官在青春期17前不久达到成人的大小。然而,啮齿动物AOS是否已在少年的功能仍然是受争论18-20。
VSNS由其上皮地点和受体的表达,他们的类型都区分。 VSNS显示与无髓鞘的轴突和凸出朝向腔和在微绒毛树突旋钮结束单个顶端树突双极形态。 VSN斧附件束状形成犁鼻神经留下的后背成尾端软骨胶囊,沿隔上升,通过筛板和项目的嗅球(AOB)21,22。犁鼻感觉上皮由两层组成:根尖层位于更靠近腔侧和港口都V1R-和所有,但一种类型的FPR-RS-表达神经元。这些神经元共表达的G蛋白α亚单位ģαi2和项目的AOB 23-25 的前部。感觉神经元位于更基底层明示或V2Rs FPR-RS1一起摹αo和发送它们的轴突的AOB 26-28后区。
犁鼻神经元是由相当小的化学信息素29-33(V1Rs)或蛋白质化合物34-38(V2Rs),该被分泌到各种体液,如尿,唾液和泪液可能激活37,39-41 </sup> 原位实验已经表明VSNS也由甲酰化肽和各种抗微生物/炎症联化合物25,42激活。此外,异源表达的FPR-RS蛋白与免疫系统中表达的FPR共享激动剂光谱,说明作为检测器,用于在同种或变质食品来源25疾病中的潜在作用(见附图43)。
从根本上理解受体 – 配体的关系和下游信号通路在特定人群VSN是他们的基本生物物理特性在本地环境的详细评测。在过去,细胞信号的分析,大大从转基因动物,通过共表达的荧光标记蛋白30,44-49标记定义的神经元群体中受益。在这个协议中,(FPR-RS3-I-金星)用来与一个荧光标记物一起表达FPR-RS3的转基因小鼠品系。这种方法举例说明如何使用这样的遗传修饰的小鼠品系进行急性冠状VNO组织切片使用单个神经元的膜片钳记录的光学可识别的细胞群的电生理分析。气压驱动的多管灌注系统的感官刺激和药物制剂可录制时快速,可逆和联络神经元的刺激或抑制作用。在片制剂全细胞记录允许固有特性,电压激活电导在细胞的天然环境中的详细分析,以及动作电位放电图形。
该VNO是化学感受结构检测信息素。迄今为止,大多数犁鼻受体保持为仅少数受体 – 配体对已确定要deorphanized。其中,V1rb2被描述由男性泌尿信息素的2-庚酮30可以具体地激活,V2rp5于由男性具体信息素ESP1 57以及V2r1b和V2rf2由MHC肽激活SYFPEITHI激活48和SEIDLILGY 58分别。理解受体 – 配体的关系及信号转导的先决条件是在天然环境中定义VSN种群的生物物理特性的知识。无源和?…
The authors have nothing to disclose.
We thank Ivan Rodriguez and Benoit von der Weid for generating the FPR-rs3-i-venus mouse line, their constructive criticism and fruitful discussions. This work was funded by grants of the Volkswagen Foundation (I/83533), the Deutsche Forschungsgemeinschaft (SP724/6-1) and by the Excellence Initiative of the German federal and state governments. MS is a Lichtenberg Professor of the Volkswagen Foundation.
Chemicals | |||
Agarose (low-gelling temperature) | PeqLab | 35-2030 | |
ATP (Mg-ATP) | Sigma-Aldrich | A9187 | |
Bis(2-hydroxyethyl)-2-aminoethanesulfonic acid (BES) | Sigma-Aldrich | B9879 | |
Calcium chloride | Sigma-Aldrich | C1016 | |
Ethylene glycol tetraacetic acid (EGTA) | Sigma-Aldrich | E3889 | |
Glucose | Sigma-Aldrich | G8270 | |
GTP (Na-GTP) | Sigma-Aldrich | 51120 | |
(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES) | Sigma-Aldrich | H3375 | |
Magnesium chloride | Sigma-Aldrich | M8266 | |
Potassium chloride | Sigma-Aldrich | P9333 | |
Potassium hydroxide | Sigma-Aldrich | 03564 | |
Sodium chloride | Sigma-Aldrich | S7653 | |
Sodium hydrogen carbonate | Sigma-Aldrich | S5761 | |
Sodium hydroxide | Sigma-Aldrich | S8045 | |
Surgical tools and consumables | |||
Large petri dish, 90 mm | VWR | decapitation, dissection of VNO capsule | |
Small petri dish, 35 mm | VWR | lid for VNO dissection, dish for embedding in agarose | |
Sharp large surgical scissor | Fine Science Tools | decapitation, removal of lower jaw | |
Strong bone scissors | Fine Science Tools | cutting incisors | |
Medium forceps, Dumont tweezers #2 | Fine Science Tools | removing skin and palate | |
Micro spring scissors, 8.5 cm, curved, 7 mm blades | Fine Science Tools | cutting out VNO | |
Two pairs of fine forceps, Dumont tweezers #5 | Fine Science Tools | dissecting VNO out of cartilaginous capsule | |
Small stainless steel spatula | Fine Science Tools | handling agarose block and tissue slices | |
Surgical scalpel | cutting agarose block into pyramidal shape | ||
Name | Company | Catalog Number | Comments |
Equipment | |||
Amplifier | HEKA Elektronik | EPC-10 | |
Borosilicate glass capillaries (1.50 mm OD/0.86 mm ID) | Science Products | ||
CCD-camera | Leica Microsystems | DFC360FX | |
Filter cube, excitation: BP 450-490, suppression: LP 515 | Leica Microsystems | I3 | |
Fluorescence lamp | Leica Microsystems | EL6000 | |
Hot plate magnetic stirrer | Snijders | 34532 | |
Microforge | Narishige | MF-830 | |
Micromanipulator Device | Luigs & Neumann | SM-5 | |
Micropipette puller, vertical two-step | Narishige | PC-10 | |
Microscope | Leica Microsystems | CSM DM 6000 SP5 | |
Noise eliminator 50/60 Hz (HumBug) | Quest Scientific | ||
Objective | Leica Microsystems | HCX APO L20x/1.00 W | |
Oscilloscope | Tektronik | TDS 1001B | |
Osmometer | Gonotec | Osmomat 030 | |
Perfusion system 8-in-1 | AutoMate Scientific | ||
pH Meter five easy | Mettler Toledo | ||
Pipette storage jar | World Precision Instruments | e212 | |
Recording chamber | Luigs & Neumann | Slice mini chamber | |
Razor blades | Wilkinson Sword GmbH | Wilkinson Sword Classic | |
Oxygenating slice storage chamber; alternative commercial chambers are e.g. BSK1 Brain Slice Keeper (Digitimer) or the Pre-chamber (BSC-PC; Warner Instruments) | custom-made | ||
Stereo microscope | Leica Microsystems | S4E | |
Trigger interface | HEKA Elektronik | TIB-14 S | |
Vibratome | Leica Microsystems | VT 1000 S | |
Water bath | Memmert | WNB 45 |