Yazarlar Bakalorya bilim programı Postane ve Novartis Enstitüleri Bu çalışmada finansmanı için bir bütün olarak Biyomedikal araştırma için teşekkür etmek istiyorum.

1. hücre hazırlanması
Not: NR1 ve NR2A hücreleri kodlama bir baculovirus ile transduced HEK293 hücreleri veri üretimi, dahil olmak üzere bu protokolü kullanır.
<ol><li>HEK293 hücreler uygun sayıda tohum ve NR1 ve/veya NR2A virüs uygun son konsantrasyonları (1.00 her µL) ekleyin. 384-şey plaka için 10.000 30 µL son bir hacim içinde hücre/iyi kullanın.</li>
	<li>Alternatif olarak, tohum HEK293-NR1-NR2A hücreleri uygun cep telefonu numarasını ve birim (384-şey plaka, kullanım 10.000 hücre/kuyuda son hacmi 30 µL için). Tetrasiklin bir konsantrasyon 2 µg/mL NR2A ifade teşvik ve bileşik koruma eklemek için Ekle (100 µM MDL105, 519 veya 5 mikron CGP07066724).</li>
	<li>Not: NR1 ve NR2 kodlama baculovirus 5 x 109 - 10 x 109 bulaşıcı mililitre24birim arasında yaklaşık bir titresi olmalıdır.</li>
</ol>2. NMDA reseptör etkinlik ölçümü
<ol><li>384-şey plaka ya da koruyucu bileşik huzurunda NR1/NR2 veya HEK293-NR1-NR2A hücreleri ile transduced HEK293 hücreleri ile hazır olun. Bir açık alt, siyah çerçeve, poli-D-lizin boyalı tabak kullanın. Not: Koruma 100 µM ile MDL105, 519 glisin, 5 mikron ise duyarlılık görüşmek için kullanılır CGP070667 glutamat duyarlılık görüşmek için kullanılır.</li>
	<li>Plaka 37 ° C ve % 5 CO2 (gece) on altı saat kuluçkaya.</li>
	<li>Plaka da kuluçka kaldır ve yavaşça hücre medya plaka uyumlu Biyoatik konteyner üzerinde saygısız yavaşlatarak atın. Plaka basına kapalı plaka kenarlarını temizlemek ve kalan herhangi bir medya drenaj için kağıt havlu üzerine hafifçe dokunun.</li>
	<li>Calcium6 boya calcium6 boya (1 plaka boyutu) bir şişe çözücü tarafından 10 mL kuluçka arabellek (HBSS pH 7.5, 20 mM HEPES, 1 mM MgCl2, 1 mM Probenesid) hazırlayın. 2 saat 37 ° C ve % 5 CO2plaka kuluçkaya.</li>
	<li>Plaka da kuluçka kaldırmak ve oda sıcaklığında 10 dakika boyunca ayarlamak hücreleri izin.</li>
	<li>Yavaşça 2.3 adımda anlatıldığı gibi calcium6-boya dökmek ve tahlil arabelleği (HBSS pH 7.5, 20 mM HEPES, 1.8 mM CaCl2, 1 mM Probenesid) 30 µL ekleyin.</li>
	<li>2.6 iki kez olmak üzere toplam 3 yıkar, adımları yineleyin. Tahlil arabelleği 30 µL hücreleri üzerinde son yıkama sonra bırakın.</li>
	<li>Oda sıcaklığında 5 dakika dinlenme hücreleri izin.</li>
	<li>Ligand plaka 400 µM glisin ve 400 µM glutamat (100 µM son konsantrasyonu; aşağıda açıklandığı gibi belirlenecek ligandlar en iyi konsantrasyon) 4-fold bir stok yaparak hazırlamak. En az 25 µL ligand stokunun bir V-alt 384-şey plaka aktarın.</li>
	<li>Ligand plaka ve hücre plaka FDSS (fonksiyonel uyuşturucu eleme sistemi) yerleştirin.</li>
	<li>Temel Floresan (Fo) hücre plaka 30 saniye için ölçmek. 10 µL ligand stokunun FDSS dağıtım işlevini ve ölçü kalsiyum akı calcium6-boya floresans 5 dakika kaydederek kullanarak hücre plaka içine aktarın.</li>
	<li>Temel Floresan (Fmax/Fo) tarafından elde edilen maksimal floresans bölerek maksimal floresans oranını hesaplamak.</li>
</ol>3. NMDAR ifade düzey optimizasyon
<ol><li>Baculovirus kullanmak için en uygun miktarını belirlemek için bir titrasyon NR1 ve NR2A virüslerin gerçekleştirin. HEK293 hücreler (10.000 hücre/iyi tavsiye, medya 30 µL) 384-şey plakalı hazırlamak ve 2.1 adımda anlatıldığı gibi koruma bileşikleri içerir.</li>
	<li>NR1 virüs değişen miktarlarda plaka farklı satırları ekleyin (örneğin: 0 µL, 2 µL, 1 µL, 0.5 µL, 0,25 µL satırları AE sırasıyla Ekle). Veri doğruluğunu çoğaltmaları ekleyin.</li>
	<li>NR2A virüs değişen miktarlarda plaka farklı sütunlar ekleyin (örneğin: 0 µL, 2 µL, 1 µL, 0.5 µL, 0,25 µL satırları AE sırasıyla Ekle). Veri doğruluğunu çoğaltmaları ekleyin.</li>
	<li>Plaka 37 ° C ve % 5 CO2 (gece) on altı saat kuluçkaya.</li>
	<li>En iyi oranı ve NR1 ve NR2A virüs miktarı FDSS (yukarı bakın) kalsiyum akı ölçüm gerçekleştirerek belirler.</li>
</ol>4. ligand titrasyon
<ol><li>Hücreleri 2.3. adımda açıklandığı şekilde hazırlayın.</li>
	<li>Her ligand konsantrasyonu (100 µM) doyurarak huzurunda dilutions 4-fold hisse senedi çözüm olarak diğer ligand hazırlayın. Örneğin: bir 10 µM son test konsantrasyon glisin için glisin 400 µM glutamat dahil olmak üzere 40 µM stok çözeltisi hazırlamak.</li>
	<li>2.11. adımda açıklandığı gibi FDSS ölçüm ile devam edin.</li>
</ol>5. test bileşik
<ol><li>1. adımda açıklandığı şekilde hücreleri hazırlayın.</li>
	<li>Son ligand konsantrasyonu tahlil arabellekte bir 5-fold hazır ligand plakalı hazırlayın.</li>
	<li>Bileşikler plaka tahlil arabellekte bileşiklerin istenen son konsantrasyonunun 4-fold hisse senedi ile hazırlayın. Bir son bileşik konsantrasyon tahlil arabelleğinde 10 µM için 40 µM hisse senedi çözüm hazırlamak.<ol>
<li>Dimetil sülfoksit (DMSO) konsantrasyonu daha fazla seyreltme tahlil arabellek içine önce DMSO bahçedeki öncesi bir seyreltme hazırlayarak tüm örnekler üzerindeki sabit tutmak.</li>
		<li>Bahçedeki 3 ve 30 µM arasında değişen son tahlil bir doz yanıt için 1'den 10 mM den kadar DMSO bahçedeki öncesi bir seyreltme hazırlayın. Bu 4-fold hisse senedi toplama için tahlil arabellekte oranında seyreltin. DMSO son konsantrasyonu % 0.5 aşmaması gerekir. Not: Bu triplicates içinde her bir örneği test etmek için tavsiye edilir.</li>
	</ol>
</li>
	<li>Ligand, bileşik ve hücre plaka FDSS yükleyin.</li>
	<li>30 saniye için temel floresans ölçmek.</li>
	<li>Bileşik stokunun 10 µL ekleyin ve 5 dakika floresans ölçmek.</li>
	<li>Ligand stokunun 10 µL ekleyin ve 5 dakika floresans ölçmek.</li>
	<li>Ölçüm son 5 dakika boyunca floresan oranları eğri altındaki alan hesaplayarak floresans oranı integrali belirlemek. Not: Alternatif olarak, floresans ligand ek sonra maksimal oranı analiz için kullanılabilir.</li>
</ol>

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Yazarlar hiçbir çıkar çatışmaları ve ifşa etmek bir şey yok.

Bu tahlil başarısı büyük ölçüde kullanılan HEK hücre sağlık üzerinde bağlıdır. Hücreleri üstel büyüme geçiyor ve düşük geçiş numarası ile kullanılmalıdır. Bu tahlil birçok transferleri içerir ve eklemeler çözümleri, çok dikkatli kullanarak sonuçları daha yüksek doğruluk sağlayacaktır. Bileşikler ve diğer kimyasalları konsantrasyonları da çapraz-hatalarını en aza indirmek için kontrol olmalıdır. Böylece hücreleri değil ayırmak hücre medya kalsiyum akı tahlil için ...

Tıpta güncel gelişmeler ile yaşam süresi önemli ölçüde artmıştır; Ancak, çok yaşa bağlı hastalıkların yaygınlığı var. Şizofreni, amyotrofik lateral skleroz (ALS), Alzheimer hastalığı ve Parkinson hastalığı, diğerleri arasında gibi merkezi sinir sistemi (MSS) hastalıkları bir istisna vardır ve sonraki on yıl1, artırmak için öngörülen 2 , 3. N-metil-D-aspartat reseptör (NMDAR) bilinen ionotropic glutamat reseptörlerinin arıza Alzheimer hastalığı, şizofreni, travmatik beyin hasarı, felç, diyabet ve yasalar tarafından aksi gerekmekdikçe glokom diğerlerinin yanı sıra, bağlı biyolojilerinin etkili, hastalığı değiştirme tedaviler4,5,6,7gelişimi için çalışması gerekir.
NMDARs dört monomerleri veya alt birimleri4,8,9/ oluşur. NMDAR yapısal kompozisyon içinde beyin7,10gelişimsel ve bölgesel değişkenlik gösterir. NMDARs sinaptik plastisite, biliş ve ritimleri oluşturmak için nefes ve hareket11,12,13katılmaktadırlar. Voltaj bir kanal büyük ölçüde sigara-membran potansiyeli dinlenme iletken (-70 mV) ve daha fazla nüfuz iyonlar önlemek için magnezyum tarafından engellenir. Kanal iki ligandlar, glutamat ve glisin/D-serin bağlama tarafından etkinleştirilir ve sinaptik membran, eşzamanlı bir depolarizasyon AMPA reseptör, ionotropic glutamat reseptörlerinin başka bir alt sınıf tarafından aracılık. Depolarizasyon katyonlar, özellikle kalsiyum14,15,16akını etkinleştirme NMDAR, magnezyum tıkanması kaldırır. NMDAR aktivasyonu hücre hayatta kalmak için gerekli olmasına rağmen aşırı harekete geçirmek hücre ölüm17,18,-19 arası excitotoxicity yol açabilir. Bu, reseptör, karmaşık yapısı ek olarak bu çalışmaları gerçekleştirmek için zorlu etkili tedaviler geliştirmek için gerekli kılar.
NMDAR eğitim için farklı yöntemler geliştirilmiştir. Ancak, her biri uyarılar eşlik vardır. Örneğin, yaygın olarak kullanılan tekniklerden biri NMDAR-aracılı değişimler istikrarlı hücre kültürünü tetrasiklin-indüklenebilir organizatörü (Tet-On)20kontrol altında hücre içi kalsiyum ölçer floresans tabanlı bir tahlil olduğunu. Ancak, bu sistemde gerekli ligandlar supramaximal konsantrasyonları ve NMDAR inhibitörleri ölçüm sırasında mevcut gereksinimi yapar rekabetçi antagonist aktivite tespit etmek neredeyse imkansız. Diğer benzer sistemleri, fonksiyonel reseptör ifade toksisite, kanal blokerleri gibi hücre kültürleri korumak için ketamin21,22 gerektiren neden olur. Bu kanal blokerleri reseptör özünde oturmak ve yıkayayım, özellikle bir plaka tabanlı biçiminde, ki onlar reseptör fonksiyonel çalışmalar ile müdahale etmek zordur. Son olarak, yama sıkma gibi elektrofizyolojik ölçümlerde sınırlı işlem hacmi olduğunu ve çok pahalı23büyük ölçekli çalışmalar vardır. Rağmen yukarıdaki sistemleri glisin uyarmaya duyarsız; Bu nedenle, NMDAR glisin bağımlı etkinliği okuyan bir sorun haline gelmektedir.
Burada tartışılan sınırlamalar üstesinden NMDAR çalışmak için yeni bir yaklaşım açıklar. Bizim teknik baculovirus ifade reseptör alt birimleri en uygun bir oranı ile fonksiyonel düzeyde olduğu kadar az 16 saat içinde hızlı sisteme capitalizes. Ayrıca, geniş bir karakterizasyonu alt türlerinden farklı rekombinant NMDAR sağlayan bir basit ve kombinatorik yaklaşım için baculovirus kullanımına izin verir. Diğer deneyleri, bu iletişim kuralını zayıf antagonistleri kullanımı nedeniyle kanal blokerleri gerektirmez. Yöntemin en güçlü avantajı zayıf antagonisti sonra bu fiyasko, modülasyon bireysel glisin ve glutamat bağlama sitelerin yanı sıra çift modülasyon glisin/D-serin ve glutamat reseptör duyarlıdır-ligand taşıması siteleri. Tahlil NMDAR reseptör bilinen Farmakoloji ve bilinen onun pozitif ve negatif modülatörler etkileri beyannamedir. Son olarak, bu vitro hücresel tahlil nesil aşırı kalsiyum akını tarafından neden olduğu hücresel toksisite üstesinden gelir ve fonksiyonel çalışmalar reseptör NMDAR modülatörler keşifler hızlandırabilir yüksek üretilen iş moda sağlar hastalık durumlarında.

<table><tbody><tr><td>HEK-293</td><td>ATCC</td><td>CRL-1573</td><td></td></tr><tr><td>Human NMDA (NR1/NR2A) Receptor Cell Line</td><td>ChanTest Corporation</td><td>CT6120</td><td></td></tr><tr><td>pFastBac Dual Expression Vector</td><td>ThermoFisher Scientific</td><td>10712-024</td><td></td></tr><tr><td>Corning 384-well Clear Flat Bottom Microplate</td><td>Corning Life Sciences</td><td>3844</td><td></td></tr><tr><td>FLIPR Calcium 6-QF Assay Kit</td><td>Molecular Devices</td><td>R8192</td><td></td></tr><tr><td>Glycine</td><td>Sigma-Aldrich</td><td>G7126</td><td></td></tr><tr><td>Glutamate</td><td>Sigma-Aldrich</td><td>49621</td><td></td></tr><tr><td>D-serine</td><td>Sigma-Aldrich</td><td>S4250</td><td></td></tr><tr><td>L701,324</td><td>Tocris</td><td>907</td><td></td></tr><tr><td>HEPES Buffer</td><td>Boston Bio Product</td><td>BB-103</td><td></td></tr><tr><td>Magnesium Chloride Solution</td><td>Sigma-Aldrich</td><td>63069</td><td></td></tr><tr><td>Calcium Chloride</td><td>VWR</td><td>E506</td><td></td></tr><tr><td>HBSS</td><td>ThermoFisher Scientific</td><td>14025-092</td><td></td></tr><tr><td>Probenecid</td><td>ThermoFisher Scientific</td><td>P36400</td><td></td></tr><tr><td>DMEM/F-12, GlutaMAX media</td><td>ThermoFisher Scientific</td><td>10565018</td><td></td></tr><tr><td>MDL105,519</td><td>NIBR</td><td>Synthesized in house</td><td></td></tr><tr><td>NVP-AAM077</td><td>NIBR</td><td>Synthesized in house</td><td></td></tr><tr><td>CGP070667</td><td>NIBR</td><td>Synthesized in house</td><td></td></tr></tbody></table>

a high-throughput calcium-flux assay to study nmda-receptors with sensitivity to glycine/d-serine and glutamate

N-metil-D-aspartat (NMDA) reseptörleri (NMDAR) ionotropic glutamat reseptörlerinin sınıflandırılır ve öğrenme ve bellek önemli rollere sahiptir. NMDAR arıza olarak her iki bitti - veya altında - mutasyonlar, değiştirilmiş ifade, kaçakçılığı veya yerelleştirme, neden activity ifade, merkezi sinir sistemi özellikle çok sayıda hastalık katkıda bulunabilir. Bu nedenle, reseptör'ın biyoloji anlama hem de keşif bileşikler ve küçük moleküller kolaylaştırmak nörolojik hastalıklar ile mücadele için devam eden çabaları önemlidir. Reseptör eğitimi için geçerli yaklaşımlar iş hızı düşük, yüksek maliyet ve NMDAR-aracılı excitotoxicity önlemek için işlevsel yetenekleri kanal blokerleri gerekli varlığı nedeniyle çalışmaya yetersizlik de dahil olmak üzere bazı kısıtlamalara sahiptir. Ayrıca, varolan tahlil sistemleri stimülasyon glutamat sadece tarafından duyarlıdır ve glisin, NMDAR, diğer eş ligand stimülasyon duyarlılık eksikliği. Burada, hem eş ligandlar, glutamat ve D-serin/glisin hassasiyetle NMDA reseptör çalışmaya yüksek üretilen iş gücü ile ilk plaka tabanlı tahlil mevcut. Bu yaklaşım farklı NMDAR alt birim besteleri incelenmesi ve fonksiyonel çalışmalar reseptör glisin - ve/veya glutamat duyarlı modlarında izin verir. Ayrıca, yöntem inhibitörleri varlığı ölçümler sırasında gerektirmez. Pozitif ve negatif allosteric modülatörler etkileri bu tahlil ile tespit edilebilir ve NMDAR bilinen Farmakoloji sistemimizde çoğaltılır. Bu teknik ve varolan yöntemleri kısıtlamaları üstesinden maliyet-etkili. Biz bu roman tekniği NMDAR-aracılı patolojiler için terapiler keşfi hızlandıracak inanıyoruz.

Küçük moleküller etkileri test etmeden önce bir yanı sıra en iyi ligand konsantrasyonu NMDARs en iyi ifade düzeyleri belirlemeniz gerekir. Açıklandığı hücreleri 384-şey plaka bir kuyu başına 10.000 hücre, seribaşı HEK293 huzurunda 5 mikron CGP060667, sonra transduced değişen miktarlarda NR1 ve NR2A virüs. Kuluçka gecede, ligand kaynaklı kalsiyum sonra akı ölçüldü (Şekil 1). Bu deneylerin sonuçlarını en iyi miktar ve her alt b...

Watch this Scientific Journal Video about A High-throughput Calcium-flux Assay to Study NMDA-receptors with Sensitivity to Glycine/D-serine and Glutamate at JoVE.com

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

NMDA reseptörleri glisin/D-serin ve glutamat duyarlılık ile çalışmak için bir yüksek-den geçerek kalsiyum-flux tahlil

NMDA reseptörleri (NMDAR) çalışma daha büyük ölçekli, kolaylaştırmak ve küçük moleküller düzenleyici etkileri muayene ve tedavi uygulamaları izin vermek için bu iletişim kuralını hedefidir.

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

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Research

JoVE Journal

Neuroscience

9.2K Görüntüleme.  Novartis Institutes for BioMedical Research. NMDA reseptörleri (NMDAR) çalışma daha büyük ölçekli, kolaylaştırmak ve küçük moleküller düzenleyici etkileri muayene ve tedavi uygulamaları izin vermek için bu iletişim kuralını hedefidir.

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

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.

Astrositik Transporter Akımlar bir Dekonvolüsyon Analizi ile Glutamat Gümrükleme gün Dersin türetilmesi

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

Nörobilim

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

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

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

Çoklu foton İntrasellüler Sodyum Görüntüleme CA1 piramidal Nöronlar Glutamatın UV-aracılı Odak uncaging ile birlikte

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

A "Dual-Addition" Calcium Fluorescence Assay for the High-Throughput Screening of Recombinant G Protein-Coupled Receptors

G protein-coupled receptors (GPCRs) represent the largest superfamily of receptors and are the targets of numerous human drugs. High-throughput screening (HTS) of random small molecule libraries against GPCRs is used by the pharmaceutical industry for target-specific drug discovery. In this study, an HTS was employed to identify novel small-molecule ligands of invertebrate-specific neuropeptide GPCRs as probes for physiological studies of vectors of deadly human and veterinary pathogens.
The invertebrate-specific kinin receptor was chosen as a target because it regulates many important physiological processes in invertebrates, including diuresis, feeding, and digestion. Furthermore, the pharmacology of many invertebrate GPCRs is poorly characterized or not characterized at all; therefore, the differential pharmacology of these groups of receptors with respect to the related GPCRs in other metazoans, especially humans, adds knowledge to the structure-activity relationships of GPCRs as a superfamily. An HTS assay was developed for cells in 384-well plates for the discovery of ligands of the kinin receptor from the cattle fever tick, or southern cattle tick, Rhipicephalus microplus. The tick kinin receptor was stably expressed in CHO-K1 cells.
The kinin receptor, when activated by endogenous kinin neuropeptides or other small molecule agonists, triggers Ca2+ release from calcium stores into the cytoplasm. This calcium fluorescence assay combined with a &#34;dual-addition&#34; approach can detect functional agonist and antagonist &#34;hit&#34; molecules in the same assay plate. Each assay was conducted using drug plates carrying an array of 320 random small molecules. A reliable Z&#39; factor of 0.7 was obtained, and three agonist and two antagonist hit molecules were identified when the HTS was at a 2 &#181;M final concentration. The calcium fluorescence assay reported here can be adapted to screen other GPCRs that activate the Ca2+ signaling cascade.

In this work, a high-throughput, intracellular calcium fluorescence assay for 384-well plates to screen small molecule libraries on recombinant G protein-coupled receptors (GPCRs) is described. The target, the kinin receptor from the cattle fever tick, Rhipicephalus microplus, is expressed in CHO-K1 cells. This assay identifies agonists and antagonists using the same cells in one "dual-addition" assay.

Rekombinant G Proteinine Bağlı Reseptörlerin Yüksek Verimli Taraması için "Çift İlaveli" Bir Kalsiyum Floresan Testi

G protein-coupled receptors (GPCRs) represent the largest superfamily of receptors and are the targets of numerous human drugs. High-throughput screening ...

Biyokimya

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

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

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

Enzim bazlı biyosensörlerin kullanılması Alzheimer Fare Modellerinde Tonik ve Fazik glutamat Ölçmek için

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

A High-content Assay for Monitoring AMPA Receptor Trafficking

Postsynaptic trafficking of receptors to and from the cell surface is an important mechanism by which neurons modulate their responsiveness to different stimuli. The &#945;-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, which are responsible for fast excitatory synaptic transmission in neurons, are trafficked to and from the postsynaptic surface to dynamically alter neuronal excitability. AMPA receptor trafficking is essential for synaptic plasticity and can be disrupted in neurological disease. However, prevalent approaches for quantifying receptor trafficking ignore entire receptor pools, are overly time- and labor-intensive, or potentially disrupt normal trafficking mechanisms and therefore complicate the interpretation of resulting data. We present a high-content assay for the quantification of both surface and internal AMPA receptor populations in cultured primary hippocampal neurons using dual fluorescent immunolabeling and a near-infrared fluorescent 96-well microplate scanner. This approach facilitates the rapid screening of bulk internalized and surface receptor densities while minimizing sample material. However, our method has limitations in obtaining single-cell resolution or conducting live cell imaging. Finally, this protocol may be amenable to other receptors and different cell types, provided proper adjustments and optimization.

Neuronal excitability can be modulated through a dynamic process of endo- and exocytosis of excitatory ionotropic glutamate receptors. Described here is an accessible, high-content assay for quantifying surface and internal receptor population pools.

AMPA izlemek için bir yüksek-içerik tahlil reseptör ticareti

Postsynaptic trafficking of receptors to and from the cell surface is an important mechanism by which neurons modulate their responsiveness to different ...

An Antibody Feeding Approach to Study Glutamate Receptor Trafficking in Dissociated Primary Hippocampal Cultures

Cellular responses to external stimuli heavily rely on the set of receptors expressed at the cell surface at a given moment. Accordingly, the population of surface-expressed receptors is constantly adapting and subject to strict mechanisms of regulation. The paradigmatic example and one of the most studied trafficking events in biology is the regulated control of the synaptic expression of glutamate receptors (GluRs). GluRs mediate the vast majority of excitatory neurotransmission in the central nervous system and control physiological activity-dependent functional and structural changes at the synaptic and neuronal levels (e.g., synaptic plasticity). Modifications in the number, location, and subunit composition of surface expressed GluRs deeply affect neuronal function and, in fact, alterations in these factors are associated with different neuropathies. Presented here is a method to study GluR trafficking in dissociated hippocampal primary neurons. An &#34;antibody-feeding&#34; approach is used to differentially visualize GluR populations expressed at the surface and internal membranes. By labeling surface receptors on live cells and fixing them at different times to allow for receptors endocytosis and/or recycling, these trafficking processes can be evaluated and selectively studied. This is a versatile protocol that can be used in combination with pharmacological approaches or overexpression of altered receptors to gain valuable information about stimuli and molecular mechanisms affecting GluR trafficking. Similarly, it can be easily adapted to study other receptors or surface expressed proteins.

This article presents a method to study glutamate receptor (GluR) trafficking in dissociated primary hippocampal cultures. Using an antibody-feeding approach to label endogenous or overexpressed receptors in combination with pharmacological approaches, this method allows for the identification of molecular mechanisms regulating GluR surface expression by modulating internalization or recycling processes.

Disanated primer hipokampal kültürlerde glutamat reseptör kaçakçılığı çalışması için antikor beslenme yaklaşımı

Cellular responses to external stimuli heavily rely on the set of receptors expressed at the cell surface at a given moment. Accordingly, the population ...

Single Synapse Indicators of Glutamate Release and Uptake in Acute Brain Slices from Normal and Huntington Mice

Synapses are highly compartmentalized functional units that operate independently on each other. In Huntington&#39;s disease (HD) and other neurodegenerative disorders, this independence might be compromised due to insufficient glutamate clearance and the resulting spill-in and spill-out effects. Altered astrocytic coverage of the presynaptic terminals and/or dendritic spines as well as a reduced size of glutamate transporter clusters at glutamate release sites have been implicated in the pathogenesis of diseases resulting in symptoms of dys-/hyperkinesia. However, the mechanisms leading to the dysfunction of glutamatergic synapses in HD are not well understood. Improving and applying synapse imaging we have obtained data shedding new light on the mechanisms impeding the initiation of movements. Here, we describe the principle elements of a relatively inexpensive approach to achieve single synapse resolution by using the new genetically encoded ultrafast glutamate sensor iGluu, wide-field optics, a scientific CMOS (sCMOS) camera, a 473 nm laser and a laser positioning system to evaluate the state of corticostriatal synapses in acute slices from age appropriate healthy or diseased mice. Glutamate transients were constructed from single or multiple pixels to obtain estimates of i) glutamate release based on the maximal elevation of the glutamate concentration [Glu] next to the active zone and ii) glutamate uptake as reflected in the time constant of decay (TauD) of the perisynaptic [Glu]. Differences in the resting bouton size and contrasting patterns of short-term plasticity served as criteria for the identification of corticostriatal terminals as belonging to the intratelencephalic (IT) or the pyramidal tract (PT) pathway. Using these methods, we discovered that in symptomatic HD mice ~40% of PT-type corticostriatal synapses exhibited insufficient glutamate clearance, suggesting that these synapses might be at risk to excitotoxic damage. The results underline the usefulness of TauD as a biomarker of dysfunctional synapses in Huntington mice with a hypokinetic phenotype.

We present a protocol to evaluate the balance between glutamate release and clearance at single corticostriatal glutamatergic synapses in acute slices from adult mice. This protocol uses the fluorescent sensor iGluu for glutamate detection, a sCMOS camera for signal acquisition and a device for focal laser illumination.

Normal ve Huntington Farelerden Akut Beyin Dilimlerinde Glutamat Salınımı ve Alımının Tek Sinaps Göstergeleri

Synapses are highly compartmentalized functional units that operate independently on each other. In Huntington&#39;s disease (HD) and other ...

Quantifying Spontaneous Ca2+ Fluxes and their Downstream Effects in Primary Mouse Midbrain Neurons

Parkinson&#8217;s disease (PD) is a devastating neurodegenerative disorder caused by the degeneration of dopaminergic (DA) neurons. Excessive Ca2+ influx due to the abnormal activation of glutamate receptors results in DA excitotoxicity and has been identified as an important mechanism for DA neuron loss. In this study, we isolate, dissociate, and culture midbrain neurons from the mouse ventral mesencephalon (VM) of ED14 mouse embryos. We then infect the long-term primary mouse midbrain cultures with an adeno-associated virus (AAV) expressing a genetically encoded calcium indicator, GCaMP6f under control of the human neuron-specific synapsin promoter, hSyn. Using live confocal imaging, we show that cultured mouse midbrain neurons display spontaneous Ca2+ fluxes detected by AAV-hSyn-GCaMP6f. Bath application of glutamate to midbrain cultures causes abnormal elevations in intracellular Ca2+ within neurons and this is accompanied by caspase-3 activation in DA neurons, as demonstrated by immunostaining. The techniques to identify glutamate-mediated apoptosis in primary mouse DA neurons have important applications for the high content screening of drugs that preserve DA neuron health.

Quantifying Spontaneous Ca2+ Fluxes and their Downstream Effects in Primary Mouse Midbrain Neurons

Here we present a protocol to measure in vitro Ca2+ fluxes in midbrain neurons and their downstream effects on caspase-3 using primary mouse midbrain cultures. This model can be employed to study pathophysiologic changes related to abnormal Ca2+ activity in midbrain neurons, and to screen novel therapeutics for anti-apoptotic properties.

Primer Fare Orta Beyin Nöronlarında Spontan Ca2+ Akılarının ve Downstream Etkilerinin Ölçülmesi

Parkinson&#8217;s disease (PD) is a devastating neurodegenerative disorder caused by the degeneration of dopaminergic (DA) neurons. Excessive Ca2+ influx ...

One-channel Cell-attached Patch-clamp Recording

Ion channel proteins are universal devices for fast communication across biological membranes. The temporal signature of the ionic flux they generate depends on properties intrinsic to each channel protein as well as the mechanism by which it is generated and controlled and represents an important area of current research. Information about the operational dynamics of ion channel proteins can be obtained by observing long stretches of current produced by a single molecule. Described here is a protocol for obtaining one-channel cell-attached patch-clamp current recordings for a ligand gated ion channel, the NMDA receptor, expressed heterologously in HEK293 cells or natively in cortical neurons. Also provided are instructions on how to adapt the method to other ion channels of interest by presenting the example of the mechano-sensitive channel PIEZO1. This method can provide data regarding the channel&#8217;s conductance properties and the temporal sequence of open-closed conformations that make up the channel&#8217;s activation mechanism, thus helping to understand their functions in health and disease.

Described here is a procedure for obtaining long stretches of current recording from one ion channel with the cell-attached patch-clamp technique. This method allows for observing, in real time, the pattern of open-close channel conformations that underlie the biological signal. These data inform about channel properties in undisturbed biological membranes.

Tek kanallı bir hücre-bağlı Patch-clamp kayıt

Ion channel proteins are universal devices for fast communication across biological membranes. The temporal signature of the ionic flux they generate ...

Biyoloji

Real-Time Fluorescent Measurement of Synaptic Functions in Models of Amyotrophic Lateral Sclerosis

Before neuronal degeneration, the cause of motor and cognitive deficits in patients with amyotrophic lateral sclerosis (ALS) and/or frontotemporal lobe dementia (FTLD) is dysfunction of communication between neurons and motor neurons and muscle. The underlying process of synaptic transmission involves membrane depolarization-dependent synaptic vesicle fusion and the release of neurotransmitters into the synapse. This process occurs through localized calcium influx into the presynaptic terminals where synaptic vesicles reside. Here, the protocol describes fluorescence-based live-imaging methodologies that reliably report depolarization-mediated synaptic vesicle exocytosis and presynaptic terminal calcium influx dynamics in cultured neurons.
Using a styryl dye that is incorporated into synaptic vesicle membranes, the synaptic vesicle release is elucidated. On the other hand, to study calcium entry, Gcamp6m is used, a genetically encoded fluorescent reporter. We employ high potassium chloride-mediated depolarization to mimic neuronal activity. To quantify synaptic vesicle exocytosis unambiguously, we measure the loss of normalized styryl dye fluorescence as a function of time. Under similar stimulation conditions, in the case of calcium influx, Gcamp6m fluorescence increases. Normalization and quantification of this fluorescence change are performed in a similar manner to the styryl dye protocol. These methods can be multiplexed with transfection-based overexpression of fluorescently tagged mutant proteins. These protocols have been extensively used to study synaptic dysfunction in models of FUS-ALS and C9ORF72-ALS, utilizing primary rodent cortical and motor neurons. These protocols easily allow for rapid screening of compounds that may improve neuronal communication. As such, these methods are valuable not only for the study of ALS but for all areas of neurodegenerative and developmental neuroscience research.

Two related methods are described to visualize subcellular events required for synaptic transmission. These protocols enable the real-time monitoring of the dynamics of presynaptic calcium influx and synaptic vesicle membrane fusion using live-cell imaging of in vitro cultured neurons.

Amiyotrofik Lateral Skleroz Modellerinde Sinaptik Fonksiyonların Gerçek Zamanlı Floresan Ölçümü

Before neuronal degeneration, the cause of motor and cognitive deficits in patients with amyotrophic lateral sclerosis (ALS) and/or frontotemporal lobe ...