著者らは、初期胚発生時にひよこ内耳の解剖学上の専門知識のためのイメージング技術と博士ドリス·ウーとの提案と支援博士キャンディHsieh氏に感謝したいと思います。この作品は、NSF、IOS-0642346、NIH T32-DC010775、NIH T32-GM008620、NIHのR01-DC010796、とDOE GAANN P200A120165によってサポートされていました。

1。以下解剖ツールおよび試薬を準備<ul><li>連続して95％Oを流し込んで、人工脳脊髄液（130mMのNaCl、3mMのKClを、1.2mMのKH 2 PO 4、20mMのNaHCO 3を 、3 mMのHEPES、10mMグルコース、2mMのCaCl 2、1.3mMのMgSO 4を ACSF）室温で2/5％CO 2で 。点滴は、2月3日ふたに穴を開けた500ml広口ナルゲン瓶に記入してください。タンクは瓶のふたの穴に通しACSFを貫通ガラスステムバブラーにチューブで接続されます。液体の約1/3に達するが、リムの上に飛散引き起こすのに十分な説得力がありません泡の一定のストリームを取得するために圧力を調整します。互いから、ガス流の乱れから、個々のサンプルを分離するナルゲン瓶に沈める5ミリリットルガラスバイアル（最大6）。 ACSFは、どの組織のインキュベーションの前に少なくとも20分間酸素化されるべきである。 </li><li>小さなシリコーン解剖皿（35ミリメートル×10小さな六角形のポリスチレンに配置された2つの解剖ピン付きシルガード弾性体キットを使用してmmペトリコーティング）（47ミリメートルの下）ボートの重量を量る。 </li><li>二つ精密チップ·鉗子、1湾曲先端鉗子、50mlビーカー、および組織廃棄用のコンテナ。 </li><li>ガラスマイクロピペット（1.2外径/ 0.9 ID）の先端の開口は約20から50程度に分割して0.4パーセントと6.25パーセント·ソリューションのトリトンX-100、PBS中におけるローダミンデキストランアミン（RDA、MW = 3000、Invitrogen社製）を充填した引っ張ら。マイクロマニピュレーターにpicospritzerして安定化する細かいチューブで取り付けます。 </li></ul> 2。顕微解剖E8 4,5で乳頭基部を明らかにする<ol><li>湾曲したピンセットで、ボートの重量を量る内にシリコーン被覆解剖皿に直接頭を置いて、ちょうど脳幹下E8胚を切った。 </li><li>興味のある側の耳が少し見えるように位置腹望むヘッドは、解剖のピンを使って、頭がわずかに背側に傾けて、CEから10から30度を指しているNTER（ 図2A）。すぐにピンと頭を固定します。二国間のトレースは、中心0度ヘッド、または両側がアクセスできるように、完全な腹ビューを希望する場合は。左側がアクセスしやすいように同様に、左サイド注入のために、中心から-30度〜-10で頭部を固定します。 </li><li> 50ミリリットルのビーカーを使用して、完全に組織を浸漬、皿に酸素化ACSFの30ミリリットルを転送します。 </li><li>そっとつかんで、精密チップ·鉗子を用いて下顎ダウンはがし、次に興味のある側に下瞼を削除します。 </li><li>残りの口蓋と食道を含め、上層の血管組織を削除します。これらの軟部組織が剥がれ、その表面に独特の椎骨動脈と軟骨頭蓋の開発の滑らかな表面を明らかにする必要があります。この時点では、特徴的な白いotoconial質量が見えるはずです。 </li><li>に残したまま、慎重に外尿道口、顎関節の軟骨、中耳の周りの​​皮膚を切開NERの耳無傷。そっとこれらの軟骨構造を切り取るために鉗子を使用しています。 </li><li>椎骨動脈を外し、細かい鉗子のヒントと穏やかな弧を描く動きを用いて血液をプール。血がビューと凝固がインジェクションピペットの開口部を塞ぐことが見えにくくなる場合があります。 </li><li>隣接感覚上皮（乳頭基部）と聴神経節と蝸牛管は軟骨頭蓋6の直下に位置し、前方の近くの最も遠位の先端（頂点）で、腹側内耳から延びる細長い指状の突起として可視化することができる正中線5。視覚化するのを助けることができる蝸牛管（ 図2B）の頂点に解離および/ ​​またはotolithic石灰（白）から少量の血液プーリング（赤）があるかもしれません。頂点にlagenar黄斑ですが、感覚パッチは前庭機能7,8であると思った。 </li></ol> 3。 CN VIII聴覚繊維の選択的標識<ol><li&gt;蝸牛管と乳頭基部領域における胚の表面付近インジェクションピペットを置きます。 </li><li>最初はゆっくり穿刺頭蓋にマイクロピペットを下げます。この頭蓋領域は、周辺地域よりも薄く、小さい力が浸透している必要があります。マイクロピペットは現在、蝸牛管の内側になければなりません。オプション：トレース染料の小さな注射は乳頭基部を視覚化するのを助けるためにここで行うことができます。 </li><li>マイクロピペットの位置を変更せずに、単に侵害それまで蝸牛管（ 図1）の深い境界線を下げ続けている。ここに注射を行うと前庭つぼが置かれている最も近位チップを除く、乳頭基部（ 図2C、2D）の長さ方向に沿って複数の地域で繰り返す。 10から30 psiの間に設定picospritzerで、いくつかの注射が行われます。注入された色素の流体の体積は変化し、所望の標識の程度に依存する。各注射は蛍光色素ラをもたらすべきである約200のbeledスポット- 400μmの直径（ 図2D）。 </li><li>注入が完了すると、脳幹上記サンプルを横断すると、継続的に95％O 2/5％CO 2下で灌流さACSFのコンテナ内に小さな瓶に尾部を配置するためにホールピペットを使用する鉗子を使用しています。 </li><li>各胚については、目的の中央トレースの距離に応じて、移染のために20-30分を許可します。 </li><li>組織を除去し、組織学的切片の準備をします。ここに示す例では、組織は4％パラホルムアルデヒド（1X PBS中）を一晩一晩、30％スクロース（1X PBS中）に浸漬されている。 </li></ol> 4。対比と分析<ol><li>対比は、解剖学的位置に向きをオブザーバを助けるだけでなく、関心のある特定の領域を識別するのに便利です。この製剤における有効対比を強くリットルニューロフィラメント免疫標識（ 図1、図3B、3E）であり、abelsは、軸索と中枢神経の軸索路の区分を可能にします。 </li><li>予測はrostrocaudal軸に沿って数百ミクロン以上を拡張することができますように分析は、標識された地域全体で行うべきである。基本的な分析のいくつかの例は以下のとおりです。ターゲットエラーレート、タイミングおよび/または投影パターンの発散の変化。 RDA-標識軸索は、高解像度（ 図3A、3D）と末梢および中枢神経系において可視化される。 </li></ol>

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利害の衝突は宣言されていません。

VIIIth神経の早期開発の研究があるため、複数の別個の神経節から生じる胚軸索を識別するのに難しさの一部に限られていた。いくつかの研究は、初期の開発中に、聴覚と前庭感覚細胞と神経節細胞の運命を導く分子シグナル、5,11,12を検討されているが、中枢神経支配を規制するプロセスがまだ決定されています。レスがプライマリ核に投射する中央のプロセスについてはほ?...

<table border="1"><tbody><tr><td> 試薬/材料の名称 </td><td> 会社 </td><td> カタログ番号 </td><td> 注釈 </td></tr><tr><td>ポリスチレンは皿を計量</td><td>フィッシャー·サイエンティフィック</td><td> 02-202-101 </td><td></td></tr><tr><td>シャーレ、35 X 10ミリメートル</td><td>フィッシャー·サイエンティフィック</td><td> 50820644 </td><td>シリコーン解剖皿を作るために使用</td></tr><tr><td>シルガードシリコーンエラストマーキット</td><td>ワールド·精密機器</td><td> SYLG184 </td><td>コー​​トペトリは、解剖皿を作る</td></tr><tr><td>解剖ピン</td><td>さまざまな</td><td></td><td>解剖時に所定の位置に胚を保持</td></tr><tr><td> NACL </td><td>さまざまな</td><td></td><td> ACSFレシピの一部</td></tr><tr><td> KClを</td><td>さまざまな</td><td></td><td> ACSFレシピの一部</TD&gt; </tr><tr><td> KH 2 PO 4 </td><td>さまざまな</td><td></td><td> ACSFレシピの一部</td></tr><tr><td> NaHCO 3を </td><td>さまざまな</td><td></td><td> ACSFレシピの一部</td></tr><tr><td>グルコース</td><td>さまざまな</td><td></td><td> ACSFレシピの一部</td></tr><tr><td> CaCl 2を </td><td>さまざまな</td><td></td><td> ACSFレシピの一部</td></tr><tr><td> MgSO 4を </td><td>さまざまな</td><td></td><td> ACSFレシピの一部</td></tr><tr><td> ACSF用のコンテナ。蓋付き透明広口ナルゲン瓶、500ミリリットル（16オンス）を示唆している。 </td><td> CPLabSafety </td><td> QP-PLC-03717 </td><td>液体浸透するガラスbublingステム用蓋の上部の穴の開口部をドリル</td></tr><tr><td>空の5ミリリットルのガラスバイアルまたは同等の透明バイアル</td><td>アメリカの製薬パートナーズ株式会社</td><td> 6332300105 </td><tD&gt;互いにおよびバブリングストリームからサンプルを別々に保管するACSFのインキュベーション中に使用</td></tr><tr><td>バブラーにチューブで接続されたcarbogenのタンク（95％O 2/5％CO 2）で</td><td>さまざまな</td><td></td><td> ACSFへの注入用ガラス幹バブラーに管によってアタッチ</td></tr><tr><td>ガラス幹バブラー</td><td>さまざまな</td><td></td><td> ACSFにcarbogenを注入する</td></tr><tr><td>先の曲がった鉗子</td><td>ワールド·精密機器</td><td> 501008 </td><td>卵から胚の頭部を削除するには</td></tr><tr><td>二つ精密チップ·鉗子</td><td>ワールド·精密機器</td><td> 501985 </td><td>顕微解剖用</td></tr><tr><td> 50mlビーカー</td><td>さまざまな</td><td></td><td></td></tr><tr><td>ローダミンデキストランアミン（RDA） </td><td>インビトロジェン</td><td>さまざまな</td><td>蛍光軸索トレーサー</td></tr><tr><td>トリトンX-100 </td><td> ICNバイオメディカル</td><td></td><td></td></tr><tr><td>リン酸塩は、（1×PBS）、緩衝生理食塩水</td><td>さまざまな</td><td></td><td>標準的な実験用試薬</td></tr><tr><td>薄壁ガラスキャピラリー、外径1.2、0.9番号4 &quot;（100mm）の長さ</td><td>ワールド·精密機器</td><td> TW120F-4 </td><td> RDAを使用したロード。各キャピラリーは、2枚のガラスマイクロピペットを作る</td></tr><tr><td>ニードル/ピペットプラー</td><td>デビッドKopfはインスツルメンツ</td><td>モデル720 </td><td>使用される設定：熱16.4、ソレノイド2.2 </td></tr><tr><td> Picospritzer </td><td>パーカー計装用</td><td>さまざまな</td><td>ガラスマイクロピペットを微管によって取り付け</td></tr><tr><td>極微操作装置</td><td>ナリシゲ</td><td>さまざまな</td><td></td></tr><tr><td>蛍光と解剖顕微鏡</td><td>さまざまな</td><td></td><td></td&gt; </tr><tr><td> 4％パラホルムアルデヒド</td><td>さまざまな</td><td></td><td>標準的な実験用試薬</td></tr><tr><td>抗ニューロフィラメント抗体、オプション</td><td>ミリポア</td><td> AB1991 </td><td>メーカーが推奨する組織学的なプロトコルに従ってください</td></tr><tr><td>クライオスタットとセクショニングの関連材料</td><td>ライカ</td><td>さまざまな</td><td></td></tr><tr><td>イメージングのための落射蛍光顕微鏡</td><td>ツァイスは、様々な</td><td></td><td></td></tr></tbody></table>

selective tracing of auditory fibers in the avian embryonic vestibulocochlear nerve

ニワトリ胚は、末梢および中枢神経節細胞の突起の研究のために広く使用されているモデルです。聴覚系では、VIIIth脳神経内聴覚軸索の選択的標識は、中枢聴覚回路発達の研究を強化するであろう。内耳の複数の感覚器官がVIIIth神経1に貢献するため、この方法は困難である。また、確実に鳥VIIIth神経軸索内の前庭グループに対して聴覚を区別するマーカーが同定されていない。回路が形成される前に、感覚誘発反応が存在していないとして、聴覚と前庭の経路は、初期胚において機能的に区別することはできません。一元的に突出したVIIIth神経軸索は、いくつかの研究でトレースされているが、聴覚軸索標識は他のVIIIth神経コンポーネント2,3からラベリングを伴っていた。ここでは、音響神経節から選択ラベへのトレースを順行するための方法を説明します開発VIIIth神経内のL聴覚軸索。まず、酸素人工脳脊髄液中に浸漬し、8日、ニワトリ胚の前頭部の部分切開した後、蝸牛管は、解剖学的なランドマークによって識別されます。次に、罰金引かガラスマイクロピペットは、音響神経節細胞が配置されているダクトと隣接深い領域にローダミンデキストランアミンを少量注入するように配置されている。注射後30分以内に、聴覚軸索は後脳に集中的に追跡され、後に、次の組織学的準備を可視化することができる。この方法では、中枢聴覚回路形成に周辺の発達研究のための便利なツールを提供します。

VIIIth神経と神経自体の解剖学的構造のコンポーネント（ 図1、図3）、複雑で入り組んである。選択的に音響神経節細胞から生じる繊維をトレースすることにより、脳幹内VIIIth神経だけでなく、一次聴覚求心性神経のセグメントがきれいにトレースすることができるとその前庭の対応（ 図2、図3）とは区別される。同様に、この技術は、音響神経節細胞の周辺の突起?...

Watch this Scientific Journal Video about Selective Tracing of Auditory Fibers in the Avian Embryonic Vestibulocochlear Nerve at JoVE.com

Selective Tracing of Auditory Fibers in the Avian Embryonic Vestibulocochlear Nerve

ここでは、神経と後脳における聴覚軸索線維の選択的なトレースのための初期のニワトリ胚の音響神経節への蛍光色素を注入し顕微解剖法を説明します。

鳥類胚性内耳神経における聴覚繊維の選択的なトレース

The embryonic chick is a widely used model for the study of peripheral and central ganglion cell projections. In the auditory system, selective labeling ...

selective-tracing-auditory-fibers-avian-embryonic-vestibulocochlear

Research

JoVE Journal

Neuroscience

9.1K ビュー.  University of California, Irvine. ここでは、神経と後脳における聴覚軸索線維の選択的なトレースのための初期のニワトリ胚の音響神経節への蛍光色素を注入し顕微解剖法を説明します。

ビデオ: Selective Tracing of Auditory Fibers in the Avian Embryonic Vestibulocochlear Nerve

Tissue Preparation and Immunostaining of Mouse Sensory Nerve Fibers Innervating Skin and Limb Bones

Detection and primary processing of physical, chemical and thermal sensory stimuli by peripheral sensory nerve fibers is key to sensory perception in animals and humans. These peripheral sensory nerve fibers express a plethora of receptors and ion channel proteins which detect and initiate specific sensory stimuli. Methods are available to characterize the electrical properties of peripheral sensory nerve fibers innervating the skin, which can also be utilized to identify the functional expression of specific ion channel proteins in these fibers. However, similar electrophysiological methods are not available (and are also difficult to develop) for the detection of the functional expression of receptors and ion channel proteins in peripheral sensory nerve fibers innervating other visceral organs, including the most challenging tissues such as bone. Moreover, such electrophysiological methods cannot be utilized to determine the expression of non-excitable proteins in peripheral sensory nerve fibers. Therefore, immunostaining of peripheral/visceral tissue samples for sensory nerve fivers provides the best possible way to determine the expression of specific proteins of interest in these nerve fibers. So far, most of the protein expression studies in sensory neurons have utilized immunostaining procedures in sensory ganglia, where the information is limited to the expression of specific proteins in the cell body of specific types or subsets of sensory neurons. Here we report detailed methods/protocols for the preparation of peripheral/visceral tissue samples for immunostaining of peripheral sensory nerve fibers. We specifically detail methods for the preparation of skin or plantar punch biopsy and bone (femur) sections from mice for immunostaining of peripheral sensory nerve fibers. These methods are not only key to the qualitative determination of protein expression in peripheral sensory neurons, but also provide a quantitative assay method for determining changes in protein expression levels in specific types or subsets of sensory fibers, as well as for determining the morphological and/or anatomical changes in the number and density of sensory fibers during various pathological states. Further, these methods are not confined to the staining of only sensory nerve fibers, but can also be used for staining any types of nerve fibers in the skin, bones and other visceral tissue.

Immunocytochemical identification of peripheral sensory nerve fiber subtypes (and detection of protein expression therein) are key to the understanding of molecular mechanisms underlying peripheral sensation. Here we describe methods for preparation of peripheral/visceral tissue samples, such as skin and limb bones, for specific immunostaining of peripheral sensory nerve fibers.

スキンと四肢骨の神経支配マウス感覚神経線維の組織の調製と免疫染色

Detection and primary processing of physical, chemical and thermal sensory stimuli by peripheral sensory nerve fibers is key to sensory perception in ...

神経科学

Viral Tracing of Genetically Defined Neural Circuitry

Classical methods for studying neuronal circuits are fairly low throughput. Transsynaptic viruses, particularly the pseudorabies (PRV) and rabies virus (RABV), and more recently vesicular stomatitis virus (VSV), for studying circuitry, is becoming increasingly popular. These higher throughput methods use viruses that transmit between neurons in either the anterograde or retrograde direction.
Recently, a modified RABV for monosynaptic retrograde tracing was developed. (Figure 1A). In this method, the glycoprotein (G) gene is deleted from the viral genome, and resupplied only in targeted neurons. Infection specificity is achieved by substituting a chimeric G, composed of the extracellular domain of the ASLV-A glycoprotein and the cytoplasmic domain of the RABV-G (A/RG), for the normal RABV-G1. This chimeric G specifically infects cells expressing the TVA receptor1. The gene encoding TVA can been delivered by various methods2-8. Following RABV-G infection of a TVA-expressing neuron, the RABV can transmit to other, synaptically connected neurons in a retrograde direction by nature of its own G which was co-delivered with the TVA receptor. This technique labels a relatively large number of inputs (5-10%)2 onto a defined cell type, providing a sampling of all of the inputs onto a defined starter cell type.
We recently modified this technique to use VSV as a transsynaptic tracer9. VSV has several advantages, including the rapidity of gene expression. Here we detail a new viral tracing system using VSV useful for probing microcircuitry with increased resolution. While the original published strategies by Wickersham et al.4 and Beier et al.9 permit labeling of any neurons that project onto initially-infected TVA-expressing-cells, here VSV was engineered to transmit only to TVA-expressing cells (Figure 1B). The virus is first pseudotyped with RABV-G to permit infection of neurons downstream of TVA-expressing neurons. After infecting this first population of cells, the virus released can only infect TVA-expressing cells. Because the transsynaptic viral spread is limited to TVA-expressing cells, presence of absence of connectivity from defined cell types can be explored with high resolution. An experimental flow chart of these experiments is shown in Figure 2. Here we show a model circuit, that of direction-selectivity in the mouse retina. We examine the connectivity of starburst amacrine cells (SACs) to retinal ganglion cells (RGCs).

A method of tracing synaptically connected neurons is described. We use TVA specificity of an upstream cell to probe whether a cell population of interest receives synaptic input from genetically defined cell types.

遺伝的に定義された神経回路のトレースウイルス

Classical methods for studying neuronal circuits are fairly low throughput. Transsynaptic viruses, particularly the pseudorabies (PRV) and rabies virus ...

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.

聴覚神経の光遺伝学的刺激

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

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.

マウス胎児の脳のトレース条件付き遺伝経シナプス

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

Laser-guided Neuronal Tracing In Brain Explants

We present a technique which combines an in vitro tracer injection protocol, which uses a series of electrical and pressure pulses to increase dye uptake through electroporation in brain explants with targeted laser illumination and matching filter goggles during the procedure. The described technique of in vitro electroporation by itself yields relatively good visual control for targetting certain areas of the brain. By combining it with laser excitation of fluorescent genetic markers and their read-out through band-passing filter goggles, which can pick up the emissions of the genetically labeled cells/nuclei and the fluorescent tracing dye, a researcher can substantially increase the accuracy of injections by finding the area of interest and controlling for the dye-spread/uptake in the injection area much more efficiently. In addition, the laser illumination technique allows to study the functionality of a given neurocircuit by providing information about the type of neurons projecting to a certain area in cases where the GFP expression is linked to the type of transmitter expressed by a subpopulation of neurons.

We describe a technique to label neurons and their processes via anterograde or retrograde tracer injections into brain nuclei using an in vitro preparation. We modified an existing method of in vitro tracer electroporation by taking advantage of fluorescently labeled mouse mutants and basic optical equipment in order to increase labeling accuracy.

脳の外植片にレーザー誘導神経トレース

We present a technique which combines an in vitro tracer injection protocol, which uses a series of electrical and pressure pulses to increase dye uptake ...

Three-dimensional Imaging and Analysis of Mitochondria within Human Intraepidermal Nerve Fibers

The goal of this protocol is to study mitochondria within intraepidermal nerve fibers. Therefore, 3D imaging and analysis techniques were developed to isolate nerve-specific mitochondria and evaluate disease-induced alterations of mitochondria in the distal tip of sensory nerves. The protocol combines fluorescence immunohistochemistry, confocal microscopy and 3D image analysis techniques to visualize and quantify nerve-specific mitochondria. Detailed parameters are defined throughout the procedures in order to provide a concrete example of how to use these techniques to isolate nerve-specific mitochondria. Antibodies were used to label nerve and mitochondrial signals within tissue sections of skin punch biopsies, which was followed by indirect immunofluorescence to visualize nerves and mitochondria with a green and red fluorescent signal respectively. Z-series images were acquired with confocal microscopy and 3D analysis software was used to process and analyze the signals. It is not necessary to follow the exact parameters described within, but it is important to be consistent with the ones chosen throughout the staining, acquisition and analysis steps. The strength of this protocol is that it is applicable to a wide variety of circumstances where one fluorescent signal is used to isolate other signals that would otherwise be impossible to study alone.

This protocol uses three-dimensional (3D) imaging and analysis techniques to visualize and quantify nerve-specific mitochondria. The techniques are applicable to other situations where one fluorescent signal is used to isolate a subset of data from another fluorescent signal.

三次元画像と人間の表皮内神経線維内のミトコンドリアの解析

The goal of this protocol is to study mitochondria within intraepidermal nerve fibers. Therefore, 3D imaging and analysis techniques were developed to ...

Imaging Serotonergic Fibers in the Mouse Spinal Cord Using the CLARITY/CUBIC Technique

Long descending fibers to the spinal cord are essential for locomotion, pain perception, and other behaviors. The fiber termination pattern in the spinal cord of the majority of these fiber systems have not been thoroughly investigated in any species. Serotonergic fibers, which project to the spinal cord, have been studied in rats and opossums on histological sections and their functional significance has been deduced based on their fiber termination pattern in the spinal cord. With the development of CLARITY and CUBIC techniques, it is possible to investigate this fiber system and its distribution in the spinal cord, which is likely to reveal previously unknown features of serotonergic supraspinal pathways. Here, we provide a detailed protocol for imaging the serotonergic fibers in the mouse spinal cord using the combined CLARITY and CUBIC techniques. The method involves perfusion of a mouse with a hydrogel solution and clarification of the tissue with a combination of clearing reagents. Spinal cord tissue was cleared in just under two weeks, and the subsequent immunofluorescent staining against serotonin was completed in less than ten days. With a multi-photon fluorescent microscope, the tissue was scanned and a 3D image was reconstructed using Osirix software.

Supraspinal projections are important for pain perception and other behaviors, and serotonergic fibers are one of these fiber systems. The present study focused on the application of the combined CLARITY/CUBIC protocol to the mouse spinal cord in order to investigate the termination of these serotonergic fibers.

CLARITY / CUBIC技術を用いたマウスの脊髄にセロトニン繊維のイメージング

Long descending fibers to the spinal cord are essential for locomotion, pain perception, and other behaviors. The fiber termination pattern in the spinal ...

In Vitro Characterization of the Electrophysiological Properties of Colonic Afferent Fibers in Rats

Dysfunction of the colonic sensory nerves has been implicated in the pathophysiology of several common conditions, including functional and inflammatory bowel diseases and diabetes. Here, we describe a protocol for the in vitro characterization of the electrophysiological properties of colonic afferents in rats. The colorectum, with the intact pelvic ganglion (PG) attached, is removed from the rat; superfused with carbogenated Krebs solution in the recording chamber; and cannulated at the oral and anal ends to allow for distension. A fine nerve bundle emanating from the PG is identified, and the multiunit afferent nerve activity is recorded using a suction electrode. Distension of the colonic segment elicits gradual increases in multiunit discharge. A principal component analysis is conducted to differentiate the low-threshold, the high-threshold, and the wide-dynamic range afferent fibers. Chemical sensitivity of colonic afferents can be studied through the bath or intraluminal administration of test compounds. This protocol can be modified for application to other species, such as mice and guinea pigs, and to study the differences in the electrophysiological properties of thoracolumbar/hypogastric and lumbosacral/pelvic afferents of the descending colon in normal and pathological conditions.

In Vitro Characterization of the Electrophysiological Properties of Colonic Afferent Fibers in Rats

Abnormal sensory function underlies visceral pain and other symptoms of functional and inflammatory bowel diseases. A protocol for the electrophysiological recording of the colonic afferent nerves in an ex vivo rat colorectum preparation is presented here.

体外ラットの結腸求心性線維の電気生理学的特性の評価

Dysfunction of the colonic sensory nerves has been implicated in the pathophysiology of several common conditions, including functional and inflammatory ...

Retrograde Neuroanatomical Tracing of Phrenic Motor Neurons in Mice

Phrenic motor neurons are cervical motor neurons originating from C3 to C6 levels in most mammalian species. Axonal projections converge into phrenic nerves innervating the respiratory diaphragm. In spinal cord slices, phrenic motor neurons cannot be identified from other motor neurons on morphological or biochemical criteria. We provide the description of procedures for visualizing phrenic motor neuron cell bodies in mice, following intrapleural injections of cholera toxin subunit beta (CTB) conjugated to a fluorophore. This fluorescent neuroanatomical tracer has the ability to be caught up at the diaphragm neuromuscular junction, be carried retrogradely along the phrenic axons and reach the phrenic cell bodies. Two methodological approaches of intrapleural CTB delivery are compared: transdiaphragmatic versus transthoracic injections. Both approaches are successful and result in similar number of CTB-labeled phrenic motor neurons. In conclusion, these techniques can be applied to visualize or quantify the phrenic motor neurons in various experimental studies such as those focused on the diaphragm-phrenic circuitry.

Here, we describe a protocol for identifying phrenic motor neurons in mice after intrapleural delivery of fluorophore conjugated cholera toxin subunit beta. Two techniques are compared to inject the pleural cavity: transdiaphragmatic versus transthoracic approaches.

マウスにおける横隔膜の運動ニューロンの逆行性神経解剖学的トレーシング

Phrenic motor neurons are cervical motor neurons originating from C3 to C6 levels in most mammalian species. Axonal projections converge into phrenic ...

Targeting Alpha Synuclein Aggregates in Cutaneous Peripheral Nerve Fibers by Free-floating Immunofluorescence Assay

To date, for most neurodegenerative diseases only a post-mortem histopathological definitive diagnosis is available. For Parkinson&#39;s disease (PD), the diagnosis still relies only on clinical signs of motor involvement that appear later on in the disease course, when most of the dopaminergic neurons are already lost. Hence, there is a strong need for a biomarker that can identify patients at the beginning of disease or at the risk of developing it. Over the last few years, skin biopsy has proved to be an excellent research and diagnostic tool for peripheral nerve diseases such as small fiber neuropathy. Interestingly, a small fiber neuropathy and alpha synuclein (&#945;Syn) neural deposits have been shown by skin biopsy in PD patients. Indeed, skin biopsy has the great advantage of being an easily accessible, minimally invasive and painless procedure that allows the analysis of peripheral nervous tissue prone to the pathology. Moreover, the possibility of repeating the skin biopsy in the course of the follow-up of the same patient allows studying the longitudinal correlation with the disease progression. We set up a standardized reliable protocol to investigate the presence of &#945;Syn aggregates in skin nerve fibers of the PD patient. This protocol involves few short fixation steps, a cryotome sectioning and then a free-floating immunofluorescence double-staining with two specific antibodies: anti Protein Gene Product 9.5 (PGP9.5) to mark the cutaneous nerve fibers and anti 5G4 for detecting &#945;Syn aggregates. It is a versatile, sensitive and easy to perform protocol that can also be applied for targeting other proteins of interest in skin nerves. The ability to mark &#945;Syn aggregates is another step forward to the use of skin biopsy as a tool for establishing a pre-mortem histopathological diagnosis of PD.

Here, we present a protocol for a free-floating indirect immunofluorescence assay on skin biopsy sections that allows for the identification of disease specific conformation variants of alpha synuclein involved in Parkinson disease and multiple proteins of the peripheral nervous system.

自由浮遊免疫蛍光アッセイによる皮下末梢神経線維におけるアルファシヌクレイン凝集体の標的化

To date, for most neurodegenerative diseases only a post-mortem histopathological definitive diagnosis is available. For Parkinson&#39;s disease (PD), the ...