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私たちは誘発、自発的な、ミニチュアシナプス活動に応答してシナプス小胞を染色し、脱色用、および脱色段階中の画像化のためのプロトコルを記載している。既存のプロトコルに加えて、我々は小型のシナプス活性に基づいて、FM脱色を観察する新しいプロトコルを含んでいた。これらのプロトコルを使用して、我々は以前に運動障害、ジストニアのモデルマウスから培養ニューロンにお?...

シナプス小胞の機能は、シナプス伝達の重要な決定因子である。彼らは、シナプス前細胞質膜（エキソサイトーシス）と融合すると、これらの小胞は、神経伝達物質を放出し、それらは、細胞膜（エンドサイトーシス）から再生し、神経伝達物質がリロードされた後にリリースの別のサイクルのための準備が。のダイナミクスとシナプス小胞のリサイクルのメカニズムの研究が大幅にスチリルのFM染料1を導入することによって加速されています。積極的に親水性の頭部基と疎水性尾部を充電しているこれらの両親媒性分子は、（ 図1A、図1BにFM1-43の立体像における複数の色素）は、可逆的にそれらを透過することなく、脂質膜を出入りすることができます。 FM色素のグループは、彼らが発する光の範囲に影響を与える類似の特徴を共有しています。例えば、FM2-10、FM1-43、FM1-84は、2つの環状化合物との間の証つの二重結合を有するW緑色発光。両者の違いは、その疎水性を決定し、従って、膜からの出口速度が（departitioning）疎水性尾部の長さである。 FM5-95およびFM4-64の場合では、3つの二重結合は、環式化合物をリンクし、それらは、赤色発光を示す。これらの染料は、それらの親水性の部分に関して異なる。それらは親水性環境に疎水性環境の相対量子収率の増加により、生体膜に挿入されるときに、すべてのFM色素は、蛍光強度が増加する。従ってFM強度の変化は、膜ターンオーバーの変化を表す。異なる色（発光スペクトル）と疎水性は、FMは、シナプス小胞のリサイクリングにおける多目的な研究ツールを染色します。 シナプス小胞のリサイクル（ 図2）を分析する際に、これらの特徴に基づいて、FM色素は、主に以下のスキームに従って使用される。ニューロンsが、それらがエンドサイトーシス（染色）を介して形成するように、シナプス小胞（のSV）中に取り込まれることを可能にする、FM色素を含有する細胞外溶液に浸されている。染料は、その後、色素のない細胞外溶液を適用することにより洗浄されるが、これはすなわちだけ積極的に受けているエンドサイトーシスは、色素（ 図2下）がロードされ、シナプス小胞のクラスターが含まれています機能性神経終末を、明らかにしている。その後のエキソサイトーシスは、細胞外空間に、FM色素の損失と蛍光の付随する損失につながる（脱色;により親水性環境へのdepartitioning離れエキソサイトーシスのサイトからの拡散の両方に）。そのためのFM蛍光強度の変化は、シナプス小胞のエキソサイトーシスとの指標である。 FM色素は様々な生物および製剤2,3におけるシナプス小胞を染色し、脱色するために使用されている。例としては、哺乳動物のneurを含める文化4-9、哺乳類の脳スライス10,11、神経筋接合部12,13、網膜双極ニューロン14,15、および蝸牛16の有毛細胞onal。 通常、このような実験で、染色や脱色の両方を広範囲にニューロン（誘発活性）を刺激することにより誘発される。外部刺激（自発的な、ミニチュアシナプス活性）9,17-19がない場合にリサイクルを持っているとして、最近、しかし、弱い刺激に応答してシナプス小胞のリサイクルも、分析されている。自発的かつ小型のシナプス活動は、活動電位の自然発火（ 図3）を含む前者で、外部刺激の非存在下で発生するものとして定義される。これらの弱いシナプス活動は、広範囲の刺激によって誘発比べFM信号における小さな変化に関連している。測定は、FMの変化ことを必要とfluorescリファレンスの強さを正確にシナプス小胞エキソサイトーシスまたはエンドサイトーシスが、強度の人為的ではない変化を反映する。アーティファクトの原因の一つは、FM色素による細胞膜の非特異的染色の存在である。この成分の漸進的なウォッシュアウトが誤ってシナプスの活動に起因する測定された蛍​​光強度の緩やかな変化につながる。この因子は、（プロトコルを参照）適切な方法によって低減することができる。アーティファクトの最も顕著な原因は、シナプス小胞の内部に保持FM色素の光退色である。 FMの強度の光退色に関連した変化が測定される生物学（シナプス）の変化と比較して小さくなければならない。 例えば、電子増倍電荷結合素子（EMCCD）カメラ感度カメラの最近の開発は、露光時間を短縮し、フルオロフォアを励起するために使用される光の強度を弱めることにより、光退色を最小限にすることが可能となる。アーティファクトのもう一つの原因は、ドリフトIですN光学顕微鏡の焦点のレベル。イメージングセッションの間に焦点ドリフトは、機械的または熱的効果によって引き起こされることができ、誤って測定された蛍​​光強度の変化につながる。 ここで我々はそれが可能で、特に、小型のシナプス活性、微弱または無刺激の文脈においてシナプス小胞のリサイクルを分析するためにFM色素を使用することを可能にするプロトコルおよび装置を記載している。我々は、培養した齧歯類海馬ニューロンを用いて、誘発された自発的シナプス事象中の小胞の染色および脱色の例を示しており、脱色相を撮像する。我々はまた、シナプスの活動へのFM色素の損失がない場合には、FM色素の光退色の程度を評価する方法を示します。

<table border="0" cellpadding="0" cellspacing="0" width="1767">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr>
			<td>Pulse generator</td>
			<td>AMPI</td>
			<td>Master-8</td>
			<td></td>
		</tr>
		<tr>
			<td>Isolated stimulator</td>
			<td>Digitimer</td>
			<td>DS3</td>
			<td></td>
		</tr>
		<tr>
			<td>Inverted microscope</td>
			<td>Nikon</td>
			<td>Eclipse TS100</td>
			<td>This is used for assessing the cell morphology at low magnification.</td>
		</tr>
		<tr>
			<td>Inverted microscope</td>
			<td>Nikon</td>
			<td>Eclipse TiE</td>
			<td>This is used for high-resolution fluorescence and transmitted light imaging, with minimal focus drift.</td>
		</tr>
		<tr>
			<td>Objective lens</td>
			<td>Nikon</td>
			<td></td>
			<td>Water-immersion lens is recommended. Oil-immersion lens is usable unless an imaged structure is deep from the coverslip surface (e.g. &#62;10 &#956;m).</td>
		</tr>
		<tr>
			<td>Filter cube</td>
			<td>Nikon</td>
			<td>77032509</td>
			<td>490/20-nm ex, 510-nm dclp, 520-nm-LP em for FM1-43</td>
		</tr>
		<tr>
			<td>Filter cube</td>
			<td>Nikon</td>
			<td>77032809</td>
			<td>490/20-nm ex, 510-nm dclp, 650-nm-LP em for FM4-64.&#160;</td>
		</tr>
		<tr>
			<td>EMCCD camera</td>
			<td>Andor Technology</td>
			<td>iXon EM+ DU-860</td>
			<td>This EMCCD camera is used for high-sensitivity detection of fluorescence.</td>
		</tr>
		<tr>
			<td>Liquid recirculating chiller</td>
			<td>Solid State Cooling Systems</td>
			<td>Oasis 160</td>
			<td>This is used for continuously perfusing the camera with chilled water for maintaining a temperature of -80&#176;C, and thereby reducing noise.</td>
		</tr>
		<tr>
			<td>LED</td>
			<td>CoolLED-Custom Interconnect</td>
			<td>490 nm&#160;</td>
			<td>This light source is used for rapid on/off control of fluorescence excitation.</td>
		</tr>
		<tr>
			<td>Image acquisition software</td>
			<td>Andor Technology</td>
			<td>Solis</td>
			<td></td>
		</tr>
		<tr>
			<td>Imaging chamber</td>
			<td>Warner Instruments</td>
			<td>RC-21BRFS</td>
			<td></td>
		</tr>
		<tr>
			<td>Fast perfusion system</td>
			<td>Warner Instruments</td>
			<td>SF-77B</td>
			<td></td>
		</tr>
		<tr>
			<td>CNQX</td>
			<td>Tocris Bioscience</td>
			<td>1045</td>
			<td></td>
		</tr>
		<tr>
			<td>D,L-AP5</td>
			<td>Tocris Bioscience</td>
			<td>0106</td>
			<td></td>
		</tr>
		<tr>
			<td>Tetrodotoxin</td>
			<td>Tocris Bioscience</td>
			<td>1069</td>
			<td>Caution: toxic reagent. Handle with care.</td>
		</tr>
		<tr>
			<td>FM1-43</td>
			<td>Invitrogen</td>
			<td>T35356</td>
			<td></td>
		</tr>
		<tr>
			<td>Aldehyde-fixable FM1-43 (FM1-43FX)</td>
			<td>Invitrogen</td>
			<td>F35355</td>
			<td></td>
		</tr>
		<tr>
			<td>FM4-64</td>
			<td>Invitrogen</td>
			<td>T13320</td>
			<td></td>
		</tr>
		<tr>
			<td>Aldehyde-fixable FM4-64 (FM4-64FX)</td>
			<td>Invitrogen</td>
			<td>F34653</td>
			<td></td>
		</tr>
		<tr>
			<td>Ionomycin</td>
			<td>Sigma-Aldrich</td>
			<td>I0634</td>
			<td></td>
		</tr>
		<tr>
			<td>Hanks&#8217; balanced salt</td>
			<td>Sigma-Aldrich</td>
			<td>H2387</td>
			<td></td>
		</tr>
		<tr>
			<td>Minimum Essential Medium</td>
			<td>Invitrogen</td>
			<td>51200-038</td>
			<td>This solution does not contain phenol red that will interfere with fluorescence imaging.</td>
		</tr>
		<tr>
			<td>Paraformaldehyde</td>
			<td>Electron Microscopy Sciences</td>
			<td>15710</td>
			<td>Caution: toxic reagent. Handle with care.</td>
		</tr>
		<tr>
			<td>Sucrose</td>
			<td>Sigma-Aldrich</td>
			<td>S7903</td>
			<td></td>
		</tr>
	</tbody>
</table>

examination of synaptic vesicle recycling using fm dyes during evoked, spontaneous, and miniature synaptic activities

機能的な神経終末におけるシナプス小胞は、エキソサイトーシスとエンドサイトーシスを受ける。このシナプス小胞の再利用を効果的に、膜ターンオーバーを明らかにするスチリルFM色素を用いて分析することができる。 FM色素の使用のための従来のプロトコルは、刺激（誘発）次のニューロンシナプス活性を分析するために設計した。最近では、プロトコルは、このような自発的またはミニチュアシナプスイベントなどの弱いシナプス活動を、同行のFM信号を分析するために利用可能となっている。 FM信号のこれらの小さな変化の分析は、撮像​​システムは、強度の小さな変化を検出するのに十分な感度でありながら大振幅の人為的変化が抑制されることを必要とする。ここでは、誘発するために適用することができるプロトコルで、自発的な、そしてミニチュアシナプスの活動を説明し、一例として、培養海馬ニューロンを使用しています。これは重要なので、このプロトコルは、FM色素の光退色率を評価する手段が組み込まれて成果物のソース強度の小さな変化を画像化する。

一例として、我々は、シナプス小胞の脱染色の時間経過（ 図4）のための代表的な結果を示す。培養海馬ニューロンは自発的シナプス活性（ステップ2.3）を使用して、FM4-64で染色し、染料を含まない溶液（溶液2すすぎ）で洗浄した。イメージングは、自発的な活動（ステップ5.3）、（連続線の最初の部分、 図4A）を使用して、初期の脱色時間経過を示す。これは、120...

Watch this Scientific Journal Video about Examination of Synaptic Vesicle Recycling Using FM Dyes During Evoked, Spontaneous, and Miniature Synaptic Activities at JoVE.com

Examination of Synaptic Vesicle Recycling Using FM Dyes During Evoked, Spontaneous and Miniature Synaptic Activities | Neuroscience | Video

Examination of Synaptic Vesicle Recycling Using FM Dyes During Evoked, Spontaneous, and Miniature Synaptic Activities

私たちは、機能的な神経末端での画像シナプス小胞のリサイクルへのスチリルのFM色素の使用を記載している。このプロトコルは、誘発するだけでなく、自発的な、ミニチュアシナプス活動にも適用することができる。プロトコルは、効果的に評価することができシナプス様々なイベントが展開されます。

誘発、自発的、およびミニチュアシナプス活動中に、FM色素を用いたシナプス小胞のリサイクルの検討

Synaptic vesicles in functional nerve terminals undergo exocytosis and endocytosis. This synaptic vesicle recycling can be effectively analyzed using ...

examination-synaptic-vesicle-recycling-using-fm-dyes-during-evoked

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20.9K ビュー.  University of Iowa Carver College of Medicine. 私たちは、機能的な神経末端での画像シナプス小胞のリサイクルへのスチリルのFM色素の使用を記載している。このプロトコルは、誘発するだけでなく、自発的な、ミニチュアシナプス活動にも適用することができる。プロトコルは、効果的に評価することができシナプス様々なイベントが展開されます。 

ビデオ: Examination of Synaptic Vesicle Recycling Using FM Dyes During Evoked, Spontaneous, and Miniature Synaptic Activities

Studying Synaptic Vesicle Pools using Photoconversion of Styryl Dyes

The fusion of synaptic vesicles with the plasma membrane (exocytosis) is a required step in neurotransmitter release and neuronal communication. The vesicles are then retrieved from the plasma membrane (endocytosis) and grouped together with the general pool of vesicles within the nerve terminal, until they undergo a new exo- and endocytosis cycle (vesicle recycling). These processes have been studied using a variety of techniques such as electron microscopy, electrophysiology recordings, amperometry and capacitance measurements. Importantly, during the last two decades a number of fluorescently labeled markers emerged, allowing optical techniques to track vesicles in their recycling dynamics. One of the most commonly used markers is the styryl or FM dye 1; structurally, all FM dyes contain a hydrophilic head and a lipophilic tail connected through an aromatic ring and one or more double bonds (Fig. 1B). A classical FM dye experiment to label a pool of vesicles consists in bathing the preparation (Fig. 1Ai) with the dye during the stimulation of the nerve (electrically or with high K+). This induces vesicle recycling and the subsequent loading of the dye into recently endocytosed vesicles (Fig. 1Ai-iii). After loading the vesicles with dye, a second round of stimulation in a dye-free bath would trigger the FM release through exocytosis (Fig. 1Aiv-v), process that can be followed by monitoring the fluorescence intensity decrease (destaining).

Although FM dyes have contributed greatly to the field of vesicle recycling, it is not possible to determine the exact localization or morphology of individual vesicles by using conventional fluorescence microscopy. For that reason, we explain here how FM dyes can also be used as endocytic markers using electron microscopy, through photoconversion. The photoconversion technique exploits the property of fluorescent dyes to generate reactive oxygen species under intense illumination. Fluorescently labeled preparations are submerged in a solution containing diaminobenzidine (DAB) and illuminated. Reactive species generated by the dye molecules oxidize the DAB, which forms a stable, insoluble precipitate that has a dark appearance and can be easily distinguished in electron microscopy 2,3. As DAB is only oxidized in the immediate vicinity of fluorescent molecules (as the reactive oxygen species are short-lived), the technique ensures that only fluorescently labeled structures are going to contain the electron-dense precipitate. The technique thus allows the study of the exact location and morphology of actively recycling organelles.

FM dyes have been of invaluable help in the understanding of synaptic dynamics. FMs are normally followed under the fluorescent microscope during different stimulation conditions. However, photoconversion of FM dyes combined with electron microscopy allows the visualization of distinct synaptic vesicle pools, among other ultrastructure components, in synaptic boutons.

スチリル染料の光変換を使用して、シナプス小胞プールの勉強

The fusion of synaptic vesicles with the plasma membrane (exocytosis) is a required step in neurotransmitter release and neuronal communication. The ...

神経科学

Quantitative Analysis of Synaptic Vesicle Pool Replenishment in Cultured Cerebellar Granule Neurons using FM Dyes

After neurotransmitter release in central nerve terminals, SVs are rapidly retrieved by endocytosis. Retrieved SVs are then refilled with neurotransmitter and rejoin the recycling pool, defined as SVs that are available for exocytosis1,2. The recycling pool can generally be subdivided into two distinct pools - the readily releasable pool (RRP) and the reserve pool (RP). As their names imply, the RRP consists of SVs that are immediately available for fusion while RP SVs are released only during intense stimulation1,2. It is important to have a reliable assay that reports the differential replenishment of these SV pools in order to understand 1) how SVs traffic after different modes of endocytosis (such as clathrin-dependent endocytosis and activity-dependent bulk endocytosis) and 2) the mechanisms controlling the mobilisation of both the RRP and RP in response to different stimuli.
FM dyes are routinely employed to quantitatively report SV turnover in central nerve terminals3-8. They have a hydrophobic hydrocarbon tail that allows reversible partitioning in the lipid bilayer, and a hydrophilic head group that blocks passage across membranes. The dyes have little fluorescence in aqueous solution, but their quantum yield increases dramatically when partitioned in membrane9. Thus FM dyes are ideal fluorescent probes for tracking actively recycling SVs. The standard protocol for use of FM dye is as follows. First they are applied to neurons and are taken up during endocytosis (Figure 1). After non-internalised dye is washed away from the plasma membrane, recycled SVs redistribute within the recycling pool. These SVs are then depleted using unloading stimuli (Figure 1). Since FM dye labelling of SVs is quantal10, the resulting fluorescence drop is proportional to the amount of vesicles released. Thus, the recycling and fusion of SVs generated from the previous round of endocytosis can be reliably quantified.
Here, we present a protocol that has been modified to obtain two additional elements of information. Firstly, sequential unloading stimuli are used to differentially unload the RRP and the RP, to allow quantification of the replenishment of specific SV pools. Secondly, each nerve terminal undergoes the protocol twice. Thus, the response of the same nerve terminal at S1 can be compared against the presence of a test substance at phase S2 (Figure 2), providing an internal control. This is important, since the extent of SV recycling across different nerve terminals is highly variable11.
Any adherent primary neuronal cultures may be used for this protocol, however the plating density, solutions and stimulation conditions are optimised for cerebellar granule neurons (CGNs)12,13.

A live fluorescence imaging technique to quantify the replenishment and mobilisation of specific synaptic vesicle (SV) pools in central nerve terminals is described. Two rounds of SV recycling are monitored in the same nerve terminals providing an internal control.

FM染料を用いて培養小脳顆粒神経細胞のシナプス小胞プールの補充の定量分析

After neurotransmitter release in central nerve terminals, SVs are rapidly retrieved by endocytosis.  Retrieved SVs are then refilled with ...

Lateral Diffusion and Exocytosis of Membrane Proteins in Cultured Neurons Assessed using Fluorescence Recovery and Fluorescence-loss Photobleaching

Membrane proteins such as receptors and ion channels undergo active trafficking in neurons, which are highly polarised and morphologically complex. This directed trafficking is of fundamental importance to deliver, maintain or remove synaptic proteins.
Super-ecliptic pHluorin (SEP) is a pH-sensitive derivative of eGFP that has been extensively used for live cell imaging of plasma membrane proteins1-2. At low pH, protonation of SEP decreases photon absorption and eliminates fluorescence emission. As most intracellular trafficking events occur in compartments with low pH, where SEP fluorescence is eclipsed, the fluorescence signal from SEP-tagged proteins is predominantly from the plasma membrane where the SEP is exposed to a neutral pH extracellular environment. When illuminated at high intensity SEP, like every fluorescent dye, is irreversibly photodamaged (photobleached)3-5. Importantly, because low pH quenches photon absorption, only surface expressed SEP can be photobleached whereas intracellular SEP is unaffected by the high intensity illumination6-10. 
FRAP (fluorescence recovery after photobleaching) of SEP-tagged proteins is a convenient and powerful technique for assessing protein dynamics at the plasma membrane. When fluorescently tagged proteins are photobleached in a region of interest (ROI) the recovery in fluorescence occurs due to the movement of unbleached SEP-tagged proteins into the bleached region. This can occur via lateral diffusion and/or from exocytosis of non-photobleached receptors supplied either by de novo synthesis or recycling (see Fig. 1). The fraction of immobile and mobile protein can be determined and the mobility and kinetics of the diffusible fraction can be interrogated under basal and stimulated conditions such as agonist application or neuronal activation stimuli such as NMDA or KCl application8,10. 
We describe photobleaching techniques designed to selectively visualize the recovery of fluorescence attributable to exocytosis. Briefly, an ROI is photobleached once as with standard FRAP protocols, followed, after a brief recovery, by repetitive bleaching of the flanking regions. This 'FRAP-FLIP' protocol, developed in our lab, has been used to characterize AMPA receptor trafficking at dendritic spines10, and is applicable to a wide range of trafficking studies to evaluate the intracellular trafficking and exocytosis.

This report describes the use of live cell imaging and photobleach techniques to determine the surface expression, transport pathways and trafficking kinetics of exogenously expressed, pH-sensitive GFP-tagged proteins at the plasma membrane of neurons.

培養神経細胞における膜タンパク質の側方拡散とエキソサイトーシスは、蛍光回復と蛍光損失光退色を用いて評価

Membrane proteins such as receptors and ion channels undergo active trafficking in neurons, which are highly polarised and morphologically complex. This ...

Deriving the Time Course of Glutamate Clearance with a Deconvolution Analysis of Astrocytic Transporter Currents

The highest density of glutamate transporters in the brain is found in astrocytes. Glutamate transporters couple the movement of glutamate across the membrane with the co-transport of 3 Na+ and 1 H+ and the counter-transport of 1 K+. The stoichiometric current generated by the transport process can be monitored with whole-cell patch-clamp recordings from astrocytes. The time course of the recorded current is shaped by the time course of the glutamate concentration profile to which astrocytes are exposed, the kinetics of glutamate transporters, and the passive electrotonic properties of astrocytic membranes. Here we describe the experimental and analytical methods that can be used to record glutamate transporter currents in astrocytes and isolate the time course of glutamate clearance from all other factors that shape the waveform of astrocytic transporter currents. The methods described here can be used to estimate the lifetime of flash-uncaged and synaptically-released glutamate at astrocytic membranes in any region of the central nervous system during health and disease.

We describe an analytical method to estimate the lifetime of glutamate at astrocytic membranes from electrophysiological recordings of glutamate transporter currents in astrocytes.

アストロサイトトランスポーター電流のデコンボリューション解析グルタミン酸クリアランスの時間経過の導出

The highest density of glutamate transporters in the brain is found in astrocytes. Glutamate transporters couple the movement of glutamate across the ...

Measuring Synaptic Vesicle Endocytosis in Cultured Hippocampal Neurons

During endocytosis, fused synaptic vesicles are retrieved at nerve terminals, allowing for vesicle recycling and thus the maintenance of synaptic transmission during repetitive nerve firing. Impaired endocytosis in pathological conditions leads to decreases in synaptic strength and brain functions. Here, we describe methods used to measure synaptic vesicle endocytosis at the mammalian hippocampal synapse in neuronal culture. We monitored synaptic vesicle protein endocytosis by fusing a synaptic vesicular membrane protein, including synaptophysin and VAMP2/synaptobrevin, at the vesicular lumenal side, with pHluorin, a pH-sensitive green fluorescent protein that increases its fluorescence intensity as the pH increases. During exocytosis, vesicular lumen pH increases, whereas during endocytosis vesicular lumen pH is re-acidified. Thus, an increase of pHluorin fluorescence intensity indicates fusion, whereas a decrease indicates endocytosis of the labelled synaptic vesicle protein. In addition to using the pHluorin imaging method to record endocytosis, we monitored vesicular membrane endocytosis by electron microscopy (EM) measurements of Horseradish peroxidase (HRP) uptake by vesicles. Finally, we monitored the formation of nerve terminal membrane pits at various times after high potassium-induced depolarization. The time course of HRP uptake and membrane pit formation indicates the time course of endocytosis.

Synaptic vesicle endocytosis is detected by light microscopy of pHluorin fused with synaptic vesicle protein and by electron microscopy of vesicle uptake.

培養海馬神経細胞のシナプス小胞エンドサイトーシスを測定

During endocytosis, fused synaptic vesicles are retrieved at nerve terminals, allowing for vesicle recycling and thus the maintenance of synaptic ...

Recording Synaptic Plasticity in Acute Hippocampal Slices Maintained in a Small-volume Recycling-, Perfusion-, and Submersion-type Chamber System

Even though experiments on brain slices have been in use since 1951, problems remain that reduce the probability of achieving a stable and successful analysis of synaptic transmission modulation when performing field potential or intracellular recordings. This manuscript describes methodological aspects that might be helpful in improving experimental conditions for the maintenance of acute brain slices and for recording field excitatory postsynaptic potentials in a commercially available submersion chamber with an outflow-carbogenation unit. The outflow-carbogenation helps to stabilize the oxygen level in experiments that rely on the recycling of a small buffer reservoir to enhance the cost-efficiency of drug experiments. In addition, the manuscript presents representative experiments that examine the effects of different carbogenation modes and stimulation paradigms on the activity-dependent synaptic plasticity of synaptic transmission.

This protocol describes the stabilization of the oxygen level in a small volume of recycled buffer and methodological aspects of recording activity-dependent synaptic plasticity in submerged acute hippocampal slices.

少量循環、血流 - と水没型チャンバー システムで管理急性海馬スライスにおけるシナプス可塑性を記録

Even though experiments on brain slices have been in use since 1951, problems remain that reduce the probability of achieving a stable and successful ...

Culturing In Vivo-like Murine Astrocytes Using the Fast, Simple, and Inexpensive AWESAM Protocol

The AWESAM (a low-cost easy stellate astrocyte method) protocol entails a fast, simple, and inexpensive way to generate large quantities of in vivo-like mouse and rat astrocyte monocultures: Brain cells can be isolated from different brain regions, and after a week of cell culture, non-astrocytic cells are shaken off by placing the culture dishes on a shaker for 6 h in the incubator. The remaining astrocytes are then passaged into new plates with an astrocyte-specific medium (termed NB+H). NB+H contains low concentrations of heparin-binding EGF-like growth factor (HBEGF), which is used in place of serum in medium. After growing in NB+H, AWESAM astrocytes have a stellate morphology and feature fine processes. Moreover, these astrocytes have more in vivo-like gene expression than astrocytes generated by previously published methods. Ca2+ imaging, vesicle dynamics, and other events close to the membrane can thus be studied in the fine astrocytic processes in vitro, e.g., using live cell confocal or TIRF microscopy. Notably, AWESAM astrocytes also exhibit spontaneous Ca2+ signaling similar to astrocytes in vivo.

Culturing In Vivo-like Murine Astrocytes Using the Fast, Simple, and Inexpensive AWESAM Protocol

The AWESAM protocol described here is optimal for culturing murine astrocytes in isolation from other brain cells in a fast, simple, and inexpensive manner. AWESAM astrocytes exhibit spontaneous Ca2+ signaling, morphology, and gene expression profiles similar to astrocytes in vivo.

生体内培養-高速、シンプルで、安価な AWESAM プロトコルを使用してマウスのアストロ サイトのように

The AWESAM (a low-cost easy stellate astrocyte method) protocol entails a fast, simple, and inexpensive way to generate large quantities of in vivo-like ...

Pentylenetetrazole-Induced Kindling Mouse Model

Pentylenetetrazole (PTZ) is a GABA-A receptor antagonist. An intraperitoneal injection of PTZ into an animal induces an acute, severe seizure at a high dose, whereas sequential injections of a subconvulsive dose have been used for the development of chemical kindling, an epilepsy model. A single low-dose injection of PTZ induces a mild seizure without convulsion. However, repetitive low-dose injections of PTZ decrease the threshold to evoke a convulsive seizure. Finally, continuous low-dose administration of PTZ induces a severe tonic-clonic seizure. This method is simple and widely applicable to investigate the pathophysiology of epilepsy, which is defined as a chronic disease that involves repetitive seizures. This chemical kindling protocol causes repetitive seizures in animals. With this method, vulnerability to PTZ-mediated seizures or the degree of aggravation of epileptic seizures was estimated. These advantages have led to the use of this method for screening anti-epileptic drugs and epilepsy-related genes. In addition, this method has been used to investigate neuronal damage after epileptic seizures because the histological changes observed in the brains of epileptic patients also appear in the brains of chemical-kindled animals. Thus, this protocol is useful for conveniently producing animal models of epilepsy.

This protocol describes a method of chemical kindling with pentylenetetrazole and provides a mouse model of epilepsy. This protocol can also be used to investigate vulnerability to seizure induction and pathogenesis after epileptic seizures in mice.

Pentylenetetrazole 誘起キンドリング マウス モデル

Pentylenetetrazole (PTZ) is a GABA-A receptor antagonist. An intraperitoneal injection of PTZ into an animal induces an acute, severe seizure at a high ...

Combining Optogenetics with Artificial microRNAs to Characterize the Effects of Gene Knockdown on Presynaptic Function within Intact Neuronal Circuits

The purpose of this protocol is to characterize the effect of gene knockdown on presynaptic function within intact neuronal circuits. We describe a workflow on how to combine artificial microRNA (miR)-mediated RNA interference with optogenetics to achieve selective stimulation of manipulated presynaptic boutons in acute brain slices. The experimental approach involves the use of a single viral construct and a single neuron-specific promoter to drive the expression of both an optogenetic probe and artificial miR(s) against presynaptic gene(s). When stereotactically injected in the brain region of interest, the expressed construct makes it possible to stimulate with light exclusively the neurons with reduced expression of the gene(s) under investigation. This strategy does not require the development and maintenance of genetically modified mouse lines and can in principle be applied to other organisms and to any neuronal gene of choice. We have recently applied it to investigate how the knockdown of alternative splice isoforms of presynaptic P/Q-type voltage-gated calcium channels (VGCCs) regulates short-term synaptic plasticity at CA3 to CA1 excitatory synapses in acute hippocampal slices. A similar approach could also be used to manipulate and probe the neuronal circuitry in vivo.

This protocol provides a workflow on how to combine artificial microRNA-mediated RNA interference with optogenetics to stimulate specifically presynaptic boutons with reduced expression of selective gene(s) within intact neuronal circuits.

オプトジェネティクスを組み合わせてそのまま神経回路内でのシナプス前機能に関する遺伝子ノックダウンの効果を特徴付ける人工マイクロ Rna

The purpose of this protocol is to characterize the effect of gene knockdown on presynaptic function within intact neuronal circuits. We describe a ...

An Optical Assay for Synaptic Vesicle Recycling in Cultured Neurons Overexpressing Presynaptic Proteins

At active presynaptic nerve terminals, synaptic vesicles undergo cycles of exo- and endocytosis. During recycling, the luminal domains of SV transmembrane proteins become exposed at the cell surface. One of these proteins is Synaptotagmin-1 (Syt1). An antibody directed against the luminal domain of Syt1, once added to the culture medium, is taken up during the exo-endocytotic cycle. This uptake is proportional to the amount of SV recycling and can be quantified through immunofluorescence. Here, we combine Syt1 antibody uptake with double transfection of cultured hippocampal neurons. This allows us to (1) localize presynaptic sites based on expression of recombinant presynaptic marker Synaptophysin, (2) determine their functionality using Syt1 uptake, and (3) characterize the targeting and effects of a protein of interest, GFP-Rogdi.

We describe an optical assay for synaptic vesicle (SV) recycling in cultured neurons. Combining this protocol with double transfection to express a presynaptic marker and protein of interest allows us to locate presynaptic sites, their synaptic vesicle recycling capacity, and determine the role of the protein of interest.

シナプス小胞の培養神経細胞シナプス蛋白質の過剰発現でリサイクルのため光アッセイ

At active presynaptic nerve terminals, synaptic vesicles undergo cycles of exo- and endocytosis. During recycling, the luminal domains of SV transmembrane ...